electric flight uk - British Electric Flight Association

ELECTRIC FLIGHT U.K.
ISSUE No. 71 WINTER 2002
THE MAGAZINE OF THE
BRITISH ELECTRIC
FLIGHT ASSOCIATION
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Electric Flight - U.K.
Issue 71 - Winter 2002
"To Encourage and Further all Aspects of Electric Model Flight in
the British Isles and Elsewhere" - B.E.F.A. Constitution
CONTENTS
BEFA Committee 2002/3 ......................... 4
Chairman's Chatter ................................. 5
Current Lines ......................................... 6
Notification of the 2003 AGM ................ 7
New-2-U ................................................. 8
A “400 Line of Models” ....................... 11
The Airco D.H.2 - Part 4 ....................... 22
Readers' Models .................................. 25
B-24D Liberator .................................... 28
Coversion of a Chris Foss Xtra-Wot ... 31
Birdy .................................................... 37
TLC from your TLO ..............................
Letter s to the Committee .....................
The NEAT Fair 2002 .............................
Electric Eighty ......................................
Electric Piggyback ................................
R.O.C.C.A. ............................................
For Sale / Wanted .................................
Event Calendar .....................................
New to Electric Flight? Start Here ........
BEFA Sales ...........................................
Advertisers Index .................................
47
52
54
62
69
73
77
79
80
82
82
Cover Photo: The cover photograph is of the ‘Birdy’, which is included as a free
plan in the centre pages of this issue. It is a relatively simple design constructed
primarily from Depron and powered by a Speed 400 motor with Günther propeller
on 8 pencells. More details can be found starting on page 33.
NEXT ISSUE. The copy date for the Spring 2003 issue is 1st March 2003, with
the magazine due for publication by 1st April 2003.
DISCLAIMER
B.E.F.A. and Electric Flight U.K. wish to point out that the content, techniques
and opinions expressed in this magazine are those of the individual authors and
do not necessarily represent the views of either the Editor of this magazine or
B.E.F.A. and its committee. All reasonable care is taken in the preparation and
compilation of the magazine, but B.E.F.A. and its committee cannot be held liable
for any error or omission in the content of this magazine or any subsequent
damage or loss arising howsoever caused.
To allow proper appreciation of the photographs used, colour copies of them will
be posted on the B.E.F.A. website after publication of this magazine. If you can,
check them out at www.befa.org.uk
E.F.-U.K.
3
BEFA Committee 2002/3
Chairman
Robert Mahoney
123 Lane End Road, High Wycombe, Bucks. HP12 4HF
EMail: [email protected]
Secretary
Peter Turner
37 Church Street, Horsley, Derbyshire. DE21 5BQ
Email:
Membership Secretary
David Andrews
2 Gainsborough Road, Kibworth Harcourt, Leicester. LE8 0SG
Email:
Treasurer
[email protected]
[email protected]
Roger Winsor
14 Butler Gardens, Market Harborough, Leics. LE16 9LY
Email:
[email protected]
Editor EF-UK
Jan Bassett
111 Plantagenet Chase, Yeovil, Somerset. BA20 2PR
Tel. 01935 472743, E-mail: [email protected]
EF-UK Printing
Brian Boughton
'Red Roofs', Vicarage Road, Thetford, Norfolk. IP24 2LH
Events Co-ordinator
Terry Stuckey
31 Dysart Avenue, Kingston-upon-Thames, Surrey. KT2 5QZ
Competition Secretary
David Beavor
34 Chestnut Close, Brampton, Huntingdon, Cambs.
Midlands Representative
Roger Winsor, details as Treasurer
Northern Representative
Bob Smith. Email: befa@
Southern Representative
Dave Chinery
251 Station Road, Hayes, Middx. UB3 4JD
South West Representative Jan Bassett, details as Editor EF-UK
Indoor & Free-Flight Rep.
Gordon Tarling
87 Cowley Mill Road, Uxbridge, Middx. UB8 2QD
Email:
Technical Liaison Officer
Alan Bedingham
17 Highcliffe Close, Wickford, Essex. SS11 8JZ
Email:
Public Relations Officer
[email protected]
[email protected]
Dave Perrett
10 High Lees, Sharnford, Leicester. LE10 3PW
Tel: 01455 272297, Email: [email protected]
Webmaster
Jan Bassett, details as Editor EF-UK - (www.befa.org.uk)
Safety Officer
Vacant
Please enclose an SAE with all correspondence to the committee.
4
E.F.-U.K.
Chairman’s Chatter
Welcome to the winter issue of your U.K. Electric Flight Magazine. Our next
event is the 2003 AGM at the Royal Spa Centre, Leamington Spa, Warks., on
March 9th (more information on page 7 of this issue).
In the last issue I asked the membership for help re the Treasurer position on our
committee, to date I have received the grand total of ZERO replies (This is getting
a habit). As you may know we cannot function without a treasurer, so please give
it some thought!
After the discussion at the TWS, and receiving e-mails and letters about the electric
thermal "A" and "B" tests (some members thought that the tests had not been
approved by the BMFA). I have now received the approval from the BMFA and
Terry Rounce the Chairman of the Achievement Scheme Review Committee for
our members to take the test at next year's fly-ins. However, we must follow the
rules set out below.
1. If you are a country member of the BMFA, i.e. not a member through an
affiliated club, all you have to do is ask myself or one of the other Silent
Flight (SF) examiners in BEFA for you to take either an "A" or "B" at one
of our fly-ins.
2. If you are a member through an affiliated club, the examiner would have
to have a letter from either your club Chairman or Secretary saying that
it's OK for you to take the tests away from your club environment.
Remember these are for electric thermal type aircraft only! If you are a SF
Chief Examiner and would like to help us please get in touch with me ASAP.
By the way we are not asking for anyone to have an "A" or "B" at our fly-ins, yet.
With the help of Peter Turner, I put on a small display at the BMFA AGM on the
23rd November. The thing that stuck in my mind about the AGM was the talk on
model flying incidents. BMFA members currently make 5 million take-offs and
landings a year. Over 4 years = 20 million, but with only 139 incidents; 50% of
these were models hitting vehicles on fly sites. We were praised for our good
record on flying models, but we can do better.
So what shall we do to lower this? The first thing is either to park further away
from the flight line or move the flight line from the car park. This will be implemented
at the BEFA Fly-Ins this coming season.
If you wish to email me, will you please use the following new address as I am
going away from Hotmail due to spam! [email protected]
That's all for now so KEEP THE WATTS UP!
Robert Mahoney
E.F.-U.K.
5
Current Lines
from the Editor
I’d firstly like to apologise for the mistake I made in the Word Search printed in
the last issue. Somehow I managed to delete one column of names from the page
and failed to notice this during my proof reading. Despite this, Franz Stockinger
managed to email me the correct answer ‘BEFA THE BRITISH ELECTRIC FLIGHT
ASSOCIATION’ only one day after I received my copy of EF-UK, pretty good.
I’d be grateful to know if you like the idea of little quizzes, etc., in the magazine
(or not). I’m quite prepared to include them as a semi-regular feature if your
interested. When prizes are available they may only be small, and I might ask you
to write a short review for a subsequent issue of the magazine. Please do send me
an email, or get in touch by other means, to let me know what you think.
I’m very glad to say that I had a great response to my plea for articles in the last
issue, and this is reflected in the varied content of this issue. I have had so much,
I have had to hold a number of articles over to the Spring issue. This is fortunate
as the Spring issue is the hardest to get content for. Look forward to a bumper
issue in April.
Despite this good fortune, please don’t let this excellent effort subside; keep the
articles & photographs coming in as basically No Content = No Magazine.
You will notice, on page 52, a letter about the scale competition at BEFA fly-ins.
This is the first letter I’ve included in the magazine in this way as I hope it will
spark-off some good ideas.
If you’ve got something that you think the members may be able to help with,
why not drop me a line. If I think it is suitable, I’ll include it for start a discussion.
Hopefully the weather in 2003 is a little kindlier so I can get
more flying in than I did in 2002.
Finally, I’d like to wish you all the best Season’s Greetings.
Jan
6
E.F.-U.K.
Notice is hereby given of the:
British Electric Flight Association
2003 Annual General Meeting
to be held on
9th March 2003
at the
Royal Spa Centre
Royal Leamington Spa, Warks.
The agenda for the meeting is:
1. Minutes of the 2002 AGM.
2. Matters Arising from the 2002 AGM.
3. Annual Reports from each of the Executive Committee Members.
4. Review the Audited Statements of Funds of the Association.
5. To elect a Committee to serve for 2003/4.
The following committee posts are due for election at this years AGM:
Chairman - Robert Mahoney has offered to remain in post.
Treasurer - Roger Winsor is standing down and nominations are required.
It is critical that someone is found to take over the Treasurer’s post as the
Association can not operate if it doesn’t have a Treasurer.
Public Relations Officer - Dave Perrett was co-opted into this post at
the last AGM and is willing to be elected to this position.
Competition Secretary - David Beavor is willing to stay in post.
Technical Liaison Officer - Alan Bedingham was co-opted to serve at
the last AGM and has offered to be elected to continue in post.
Safety Adviser - currently vacant and nominations are requested.
Nominations for members willing to undertake any of the above posts are to
be sent to the Secretary at the address on page 4. All nominations must be
received by the Secretary before 21 February 2003.
6. To set the Annual Subscription for 2003/4.
7. To Appoint the Auditors for 2003/4.
8. To vote on resolutions - No resolutions were received.
9. Any Other Business.
E.F.-U.K.
7
New-2-U
A Brief Round-up of New Items of Interest
By the time you read this the Howard
Metcalfe Models Moonraker,
Chandelle, Vendetta, Phantom F4 and
Focke-Wulf Ta152, which have been
out of production since last year, will
be newly available from Phil Dorren
of Holsworthy, Devon.
Howard Metcalfe who originally
designed and produced the models
handed over the manufacturing and
marketing rights earlier this year to
Phil in a move which will still allow
Howard to continue to design and
develop new models.
Manufacturing is already under way
and Phil who works primarily as a
consultant in computing support will
sell them via mail order as well as at
future shows, you can contact him at
the address below.
Moonraker
Having more of Howard's models back in production is good news as a lot of
instructors as Moonraker was seen as something of a benchmark for trainers
over the last decade or more. It is good to know beginners will still have access to
this outstanding model which can take them right from the novice to their 'B' test.
Those stylish aerobatic
sisters Chandelle and
Vendetta will also be a
welcome return and we
look forward to seeing
out the latest versions
when they are ready.
Vendetta
8
E.F.-U.K.
If you are into slope and
have been looking for
something just that
little bit different then
the models of the Focke
Wulf and Phantom will
make a refreshing
F4 Phantom
change. These are handy sized pocket rockets that won't break the bank.
Phil has been finishing off the work Howard had started on with the Electric
Moonraker and is developing specific electric versions of Chandelle and Vendetta
as well, so watch this space. The new versions will feature pre-painted ABS
fuselages and foam wings. The electric versions will also feature custom made
battery boxes to allow quick changing of packs, with a minimum of fuss. The
battery box moulding for the Moonraker looks extremely good and mounts to
allow the battery pack(s) to be changed through a hatch in front of the canopy.
Full details from Phil Dorren at Treetops Cottage, Week St. Mary, Holsworthy,
Devon EX22 6UH, telephone 01288 341117 or email [email protected]
Editor: Although the models shown here are fitted with i.c. motors, they are all
suitable for electric power.
Focke Wulf Ta152
E.F.-U.K.
9
The new Fun Piccolo takes over the role
of the original Piccolo. It makes it
possible to enter electric helicopter flying
at a reasonable cost. The model is very
manoeuvrable and can be flown in the
house if sufficient room is available. The
Fun Piccolo is intended to be an
extremely durable and simple design.
The installation of the equipment,
including the Piccoboard is extremely
simple. The basic Piccoboard controls
the servos, main and tail rotor motors
and also features a gyro.
They are now available in the UK and
the normal selling price of the Fun
Piccolo is around £70 for the basic kit
or £175 with the basic 4 channel
Piccoboard, 2 servos and a NiCd pack.
The Piccolo Pro is designed as a fully 3D capable machine and features collective
pitch and a G-410 motor to give extra main rotor power. This had also meant an
upgrade the tail rotor motor to allow it to keep control. It uses wooden symmetrical
section blades, with lightening holes and lead tip weights, covered in film (as the
ECO Piccolo collective pitch upgrade). It also features a much racier canopy design
to give an appearance to match the performance.
You can also fit a freewheel unit to allow autorotations, but there isn’t much
mass in the rotor so they could be tricky. It can be flown on basic 4 channel radio
gear, but to optimise the use of collective pitch and for inverted flight, a 6+ channel
computer radio is recommended.
To achieve the maximum performance
they have a brushless motor option,
which improves power in duration.
The Piccolo Pro is also recently available,
and retails for around £160, plus another
£160 for the Piccoboard Pro. See
www.ikarus-modellbau.de for more
details.
10
E.F.-U.K.
A "400 Line of Models"
by Chris Golds
My Father was an electrical engineer for most of his life after serving an
apprenticeship in steam power. My mother, sister and myself never even had to
renew a wire fuse let alone repair a plug. So my 'electricalisation' in September
1996, at my 60th birthday, meant that I had a very great deal to learn with no
engineering background to provide a basic level of knowledge.
Now that I fly only electric powered models - as I do not want to rejoin the oilysmelly-NOISY brigade and gas turbines are beyond my pocket - when I find a
formula that works I tend to stick with it and take it as far as I can. Some while
ago, my model flying friend Ron Laden built a simple all-sheet Hawk from a
magazine free-plan by Nigel Hawes and we went to fly it at a light-aircraft field in
the middle of Devon as the foot and mouth epidemic prevented us from using our
normal site.
So there we were in the back of beyond as I launched this small model and Ron
hung on with great courage and skill as it whistled around the sky for hours on
end - actually about seven minutes. We were both amazed at the model's performance
from a cheap 6 volt 400 size motor with a five-inch Günther ‘toy shop’ prop all
from seven small NiMH cells inside a total weight of 21 ounces! He recharged and
flew it again, this time with better control over the little zipping beast. I was
hooked!
I was looking at a level of electrics
that even I could follow - a small
motor with direct drive push-on prop,
a small pack and a 15A speed
controller flying an all-sheet and
therefore simple semi-scale model
which produced enormous fun at
little cost.
Kyushu 'J7WI' Shinden - My First 400 Model
Back in my workshop I sketched out
a model whose shape I had lusted
after for about fifty years but had
never tried to build - a Kyushu J7W1
Shinden which the Japanese Air
Force had built to test-fly right in the
last few days of World War Two. A
handsome shape but one blessed (or
cursed) with long and stalky
undercarriage legs needed to clear the
large five-bladed pusher prop on take-
E.F.-U.K.
11
Kyushu 'J7WI' Shinden Fly-By (Gordon Whitehead Photo)
off and touchdown.
I decided to go the simple route with a hand-launched model constructed from
sheet surfaces and a sheet box fuselage clad to shape with small sections of blue
foam - a technique which I and many others regularly use to achieve compoundcurve shapes. With 10 x 500 AR cells the model flew very well at a total weight of
24 ounces with a wing loading of 16 ounces per square foot.
The push-on prop 400 system had worked and I immediately designed another
'must-do' model - a Blackburn Beverley of 72 inches span for 4 x 400 motors but
with flaps and giant fixed undercarriage. With 8 x 3000 NiMH cells this finished
at 81 ounces with a wing loading of 19 ounces per square foot and it flew splendidly
with the flaps - when fully down - allowing a really steady descent on finals to an
accurately placed landing. A number of Beverleys built from my plan (Traplet
Plans Service) have been seen around the shows this year and each pilot that I
have spoken to has been very pleased with his model.
Next came a larger model this time of a Russian TB-3 four-engined fixed
undercarriage bomber of the 1930s at 80 inches span weighing 84 ounces for a
wing loading of just 12 ounces per square foot - a real floater of a model which I
have spun frequently as loops and rolls would not really be in tune with such an
aircraft. Again, the 400 motor system had worked well with no fuss and plenty of
performance from 8 x 3000 NiMH cells with one sortie of almost 10 minutes
12
E.F.-U.K.
Blackburn Beverley of 84 Squadron M.E.A.F, static and ‘trundling past’
E.F.-U.K.
13
TB-3 Russian bomber of 1930s period, and below cruising past on a total of 8 Amps!
14
E.F.-U.K.
Blohm und Voss 208/04
duration with no lift around at all!
After an EDF model - my Hawker Sea Hawk - I returned to the single 400 pusher
prop formula with a 32 inch span model of the Blohm und Voss 208/04 single
piston pusher fighter which was designed in 1944 but never turned into metal.
The Blohm und Voss 208 - very tricky to see
E.F.-U.K.
15
Again, I went the all-sheet with foam turtle decking route but this time I tried
hard to come out lighter. At hand-launch she weighed just 20 ounces total running
from 8 x 1600 NiMH cells and has an excellent performance with long sorties - the
best being just over 14 minutes.
However, she had one distinct disadvantage in that the model was capable of
considerable speed and aerobatic manoeuvres but had a quite disorientating "sit"
in the air leading to a couple of unscheduled 'arrivals'.
Being all sheet, repairs were simple and quick but she was an aircraft upon which
you had to keep a firm eye as she often looked as if she was approaching when
actually going the other way. Would have been a good aeroplane in a dog-fight, I
bet!
After the Bv208 came another model of 'my' DH Venom FB Mk4 which I flew as a
young RAF pilot in the 1950s. Again, I employed the Speed 400, push-on Günther
prop system and with 9 x 1600 NiMH cells the 36 inch span very near-scale model
Me and 'my' venom WR441 of XI squadron
of WR441 of XI Squadron RAF weighed just 26 ounces including the knock-off
blue foam tip tanks (which in real life I never flew without).
Meanwhile my friend Ron was continuing the 400 game with a Gloster Meteor
Mk8 (twin pusher) and an A-7 single pusher and a delicious Mk1 Spitfire with a
cunning spinner assembly so that the classic Spit nose profile is preserved.
16
E.F.-U.K.
The venom climbs away at 11 Amps
Currently he is into a twin 400 version of the Me262 which he hopes to put into
plans with one of the 'e' magazines.
After a little house building task I designed and built a twin pusher version of the
Canberra B(I) Mk 8 interdiction bomber employed by the RAF in West Germany
16 squadron Canberra B(I) Mk 8 Bomber (Interdiction)
E.F.-U.K.
17
The Canberra steaming away from a hand launch
in the '60s and '70s. I used the 4 x 20mm belly gun-pack as a convenient finger
hold for hand launching and at 48 ounces carrying 8 x 2000 NiMH cells the model
gave a most spirited performance with its 16 ounces per square foot wing loading.
Truly a satisfying model to fly with no bad habits and plenty of aerobatic
performance way beyond that of the original which was limited to +5g maximum
for its loops, rolls and LABS bombing manoeuvres.
I next wanted to build an inexpensive model to become a plan so that those of the
O/S/N brigade (see above) who wanted to 'come across' to 'e' flight but did not
Twinshooter Mk 1 (no u/c) belts past
18
E.F.-U.K.
know a volt from a micro farad ('ark at me!) could do so with a fully aerobatic
model based upon the twin 400 work that I had done. So was born the Boeing
XP27 "Twin Shooter" for which I used the colour scheme of the Boeing P-26
"Peashooter" in order to be a bright and easily-seen model upon which to learn to
become 'electrolysed'!
At 44 inches span with 42½ ounces gross weight for 2 x 6 volt 400 motors running
from 8 x 2000 NiMH cells the model is VERY aerobatic with splendid performance
with sorties long enough to get you bored into coming down to land. Either handlaunched or with a simple fixed undercarriage the model continues to give me lots
of fun per penny. The only problem is that my eyes and reaction times are not
XP-27 Twinshooter (with u/c and rudder)
really up to the whizzy-pop flying of which the XP 27 is capable. So what next,
something more stately perhaps?
At one of our frequent village parties (we have a GREAT FUN village) I was
speaking to Geoff Baldock, a retired British Airways Captain, about my Canberra
model because he had flown the English Electric bomber as a young RAF pilot
when I was flying fighters - we still wonder whether we ever had met in the air!
He said that of all the airliners he had gone on to fly, the one which stuck most in
his mind was the Comet, the Mk 4c version with pinion wing fuel tanks as flown
by him in DAN-AIR of LONDON airlines.
I have long been in love with the DH106 Comet but had avoided building it because
E.F.-U.K.
19
Dh 106 Comet 4C of Dan-Air, London
of the problems of getting enough Ducted Fan thrust from such small nacelles.
However, with my recent 400 pusher knowledge and experience I reckoned that I
could do one with 4 x 400 Günther and include retracts and flaps, as a fixed
undercarriage version just did not appeal to me. Of course I would have to splay
the jet exhausts quite a bit to accommodate the 5 inch prop discs without
overlapping but otherwise I could go for a very scale airframe at light weight.
Eventually the 86 inch span model tipped the scales at 120 ounces on 4 x 7.2 volt
400s with 5 inch Günther propellers from 10 x 3000 NiMH cells with Spring-Air
retracts; operating nose-wheel doors and four sections of flaps (the real Comet
had 8 sections!). I had to fit an unobtrusive
18 swg piano wire 'prop guard' to prevent the prop tips from touching on rotation
for take-off but apart from that and the splayed exhausts, she really looks the
part in her smart DAN-AIR colour scheme. And the aircraft registration which I
chose, G-APDJ, was one which Geoff flew regularly as Captain. Not only that, but
our friend Ilse (Geoff's wife) was a stewardess on the aeroplane with him! He came
with us on 1st September 2002 to watch the model complete its first two flights
and he was delighted, especially with the realism of its very slow flight speed.
So there we are: the Comet has gone to Flying Scale Models as a plan and my
workbench has an even larger model upon it in final drawn form. It has a total of
10 power units, six of which are pusher-props but it will have eleven units running
on take off. Any ideas what it might be? Keep squeezing the volts and Happy
Flying.
20
E.F.-U.K.
Chris Golds
The Comet's flaps at full (2 per side)
The Comet Cruising past - no spilled drinks!
E.F.-U.K.
21
The Airco D.H.2 - Part 4
by Jan Bassett
I’ve been busy again, but I’ve managed to get some more work done on my Airco
D.H.2. Firstly, the motor mount and rear support plate have been fitted to the
fuselage. I decided that due to the inevitable long drive shaft, coupled with the
heavy propeller and spinning motor, a rear support bearing was essential. This
also allow the motor to be positioned in front of the CofG, which is very useful
when you consider that there is little structure in front of the CofG.
Additionally, the rear support should be as far rear and close to the propeller as
possible. It therefore machined up an aluminium ‘top hat’ with a seat for a ball
race in the top. The front of the dummy engine actually sits over the bearing
support, providing great support.
I decided it was time to trail fit the drive train complete with dummy engine
(shown below). I decided that the rear end was a little too flexible and needed
some stiffening. I therefore added a liteply plate between the rear bulkheads and
sitting on top of the upper fuselage longerons.
The part completed fuselage with motor mount and rear support bearing
22
E.F.-U.K.
The assembled & painted Williams Bros. Inc, Le Rhone Rotary engine kit.
The position of the dummy engine is almost exactly to scale, mainly due to the
‘top hat’ rear bearing. The propeller is spaced a little further from the motor than
it should be due to the propeller adaptor. I could produce a custom adaptor which
would be very near scale, but it looks OK as it is.
My next job was to complete the Le Rhone dummy scale engine from Williams
Bros. Inc. I was planning to reinforce the kit to allow it to rotate at propeller
speed. However, this is a heavy duty polystyrene kit, which when completed is
very solid. I decided that the kit was strong enough without additional strength
(and weight) - well the propeller will only be doing around 4000 RPM.
I modified the centre of the ‘engine’ to have two flanged 1/4” I.D. Phosphor Bronze
(Oilite) bearings fitted (just visible above). This was in case I decide to gear it to
the propeller shaft, or have it stationary.
As it is currently arranged, these bearings are part of the load path from the
propeller to the rear bearing. If I decide to reduce the dummy motor speed, I’ll
have to fit a collet between the dummy motor and the rear bearing to allow maintain
the thrust being taken by the rear bearing.
E.F.-U.K.
23
Having completed the engine, I rigged it up with a 1:4 belt-drive (Yes, increasing
the RPM!) and spun it up using a cordless drill. It took the rotation, at approximately
3500 RPM, with no problems at all.
I decided that the engine only needed to painted in a fairly simple scheme, well it
will be revolving rather fast in flight. I therefore sprayed the motor overall with
Tamiya ‘Flat Aluminum’ Acrylic paint, and then painted the inlet pipes in ‘Gun
Metal’ from the same range.
The effect is reasonably good, as can be seen on the previous page, with the engine
looking the part. I may add the spark plug leads to improve the look even further,
but probably not as they would be easily damaged.
I assembled the complete drive train, with shorten shaft, to the fuselage to take
the photograph below. I guess the next thing is to determine the easiest way to
make lightweight fairings for the nose - maybe I should mould them in fibreglass?
Back to the fuselage and I added some rigging cord to simulate the diagonal bracing
between the upper and lower fuselage longerons. This rigging cord is not intended
to be functional, just to improve the look of the fuselage when it is covered.
Hopefully, I can really get down to work on the model this Winter and have it
ready for next season.
Trial fitting of Aveox 1406/4Y, 5:1 Monsterbox, long shaft, dummy motor & propeller
24
E.F.-U.K.
Readers' Models
Your chance to show the members your model(s).
This is Franz Stockinger with his enlarged Pushy Galore, which is still missing
some of the wing stripes. This model is approximately 20% larger and has a 1m
(39”) span and weighs 1.25kg (44 oz.). It is powered by a Mega 22/20/3 motor with
Graupner 8” x 6” CAM propeller and 9 Sanyo RC-2000 cells.
Franz says that it can be hand or bungee launched (when no helper is available).
The flight performance is reported as really ballistic and producing a typical pusher
configuration sound (Editor: is that a good or a bad thing for electric power?).
Editor: In case you’re interested, the Pushy Galore plan was featured in Electric
Flight International May/June 1997. I recently checked and the plan, MW2589, is
still available from the Traplet Plans Service. The original model was 816mm
(32”) span, had a wing area of 11.8 dm2 (183 sq. in.) and a recommended flying
weight of 500g (17½ oz.). It was powered by a 6v Speed 400 motor running on 7 x
Sanyo 700AR cells and a 5” x 5” or 4.7” x 4.7” Graupner CAM propeller.
E.F.-U.K.
25
I had details passed to me of three models built by Rich Flinchbaugh from South
Dennis, Massachusetts , USA.
Above is Rich Flinchbaugh holding his Aqua Sport Floatplane photographed, on
29 July 2002, with the Richmond Springs Fountain for a background. It uses a
geared Magnetic Mayhem motor with a Castle Creations Pegasus 35 controller on
10 Sanyo RC-2000 cells. The weight is about 68 oz. (1.9kg). The floats are from
Kirchner plans and it gets off fast and flies well.
Top right is Rich’s 1/9th scale model of the Italian Piaggio P-136 L2 “Royal Gull”
amphibian. This scratch-built model has a 66” (167cm) span and has a flying
weight of 8 lbs. (2.7kg). It is powered by 2 Astro 15s using a Jomar SM4 controller
and 20 Sanyo 1700 mAh cells. The take-offs are supposed to be beautiful and it
flies very realistically.
Rich says that he is interested in helping others that may be interested, to build
the outstanding model. Anyone wanting advice on these floatplanes can contact
Rich at 7 Avon Lane, South Dennis, MA 02660, USA or Tel.: +1-508-398-0296.
Finally, bottom right, is Rich’s 1941 Taylorcraft Floatplane, which is again scratchbuilt and has a span of 56” (1.4m). It is powered by a Mega 22/20//3E brushless
motor and uses a Castle Creations Phoenix 35 sensorless controller. Eight Sanyo
CP-1700 NiCds provide power for FAST take-offs and provide 10 minute flights.
26
E.F.-U.K.
1/9th scale Piaggio P-136 L2 “Royal Gull”
Scratch-built 56” (1.4m) span 1941 Taylorcraft Floatplane
E.F.-U.K.
27
B-24D Liberator
by Robin Fowler
Those of you who were witnesses to the cartwheel executed by my Liberator on
the windy Sunday afternoon at Middle Wallop this year may be heartened to know
that she still lives! – Although in disguise!
The day was becoming more and more blustery and I was foolish enough to charge
up again for another flight after lunch the Liberator having coped perfectly well
in the morning. Having done so of course I was not disposed to putting it all back
in the van without the flight I had intended to make.
Disaster struck at the point of lift-off when a gust from the port side lifted the
windward wing and I suddenly found that even ailerons and rudders together
didn’t have enough authority to correct what rapidly became almost ninety degrees
of bank. Horrified, I didn’t get around to whacking a dose of down elevator in
before the starboard wing caught the ground and there was nothing to do but
shut the throttles and hope. The airframe disassembled itself and collapsed into
an untidy heap.
On closer inspection the damage, which had at first appeared considerable, was
limited. The outer wing panels had been torn off, tearing the flat brass rods from
the wing centre section but damage to the tips was limited to broken aileron
horns (this disproved my original thought that these might not have been connected
properly to the servo thus explaining the apparent lack of control in roll axis).
Apart from the twin fins having been broken off the tailplane there was no major
damage to the tail section. The locating tube for the fixing pin had been torn away
and was still attached to the wing centre section by its pin.
The bulk of the damage was in the centre section and was not immediately apparent.
The nose glazing had been totally mashed but had saved the structure behind
from any damage at all. The main spars however had all been broken and it was
B-24D Liberator is desert colours
28
E.F.-U.K.
evident once the finish was stripped back that the two wings were only staying
together because of the various control cables and rods. Once these were
disconnected it was possible to get in with glue and splints and make the necessary
repairs.
Having used up every square inch of the grey Profilm for the upper surfaces,
which was too light in tone in any case but the only grey I could find, I was not
about to spent out another eight or nine pounds to get another roll and decided to
completely strip the airframe and start afresh. I had purchased some Diatex (the
material used as the basis for Solartex) and decided to use some of this, thus
allowing myself the choice of any colour scheme I could wish for.
Diatex is Balsaloc attached at the edges and heat shrunk over the airframe then
firmly attached with three coats of non-taut dope, of which the first is thinned.
This accepts paints very readily, but at this point I made a wrong decision. Having
found a cellulose car spray colour that I thought near enough to desert sand
colour I sprayed this on over a coat of grey primer only to run out before the
upper surfaces were complete.
I then found that the car spares shop had no more of the colour and could not say
when they would be restocked, so I had to change proverbial horses in midstream
and buy the authentic Humbrol enamels which I should have done in the first
Detailed shot of the Libertor glazing
E.F.-U.K.
29
place. It then became apparent just how far off the shade the spray paint had
been, but I left some to simulate the staining from oil and the like that streamed
from the nacelles, and augmented this by rubbing some grey on with a cloth.
One of the nice things about Diatex is that if a panel goes slack at any stage it can
be tightened up by a quick application of iron of heat gun. This has come in handy
as I soon noticed that in spite of the 50% thinning of the first coat of dope and
what I thought was a reasonably generous coating I still got a few wrinkles forming
once the model was back in the air. So that first coat of dope is all-important.
The aircraft is now completed in the desert scheme illustrated in the book “Aircraft
of World War 2” by Bill Gunston. According to this book this was the first Liberator
to fall into Axis hands as it had to land at Pachino in southern Sicily having been
damaged by flak over Naples. It was made airworthy and the original markings
painted out by the Italians and eventually went to Rechlin test centre where the
Luftwaffe gave it full German insignia.
I painted it in the Anglo-American colours it wore on the fateful raid, but went a
bit far by adding the splodges of non-matching colour the Italians would have
applied after repairs had been made. Oh well, so much for authenticity. At times
like this I always fall back on my dictum that ‘so long as it looks right on a low
fly-by it’s okay’!
uzzflight
167 Duffield Road, Derby. DE22 1AJ
Telephone: 01332 601693
Email:
[email protected]
Website:
www.buzzflight.co.uk
Hummingbird
the definitive control-line trainer - ideal for youngsters
Deluxe Kit - complete with motor, propeller, prop. adapter, spinner, wheels, balsa,
u/c wire, control-line / power wire, on-off switch, battery connectors, sundries,
building instructions & full-size plan, bellcrank and control handle. The only
other items needed are the covering and a 12v 7AH battery. £39.99 + £2.50 P&P.
Standard Kit - contains balsa, u/c wire, control-line / power wire, on-off switch,
battery connectors, sundries, building instructions & full-size plan, bellcrank and
control handle. Again the covering and a 12v 7AH battery are not included. £24.99
+ £2.50 P&P.
Plans & Instructions - £7.99 including P&P, add £5.99 for control-line / power
wire and switch. Please contact us for Overseas prices.
Please make cheques payable to Buzzflight and allow 14 days for delivery.
30
E.F.-U.K.
Conversion of the Chris Foss
“Xtra – Wot” To Electric.
by Paul Cook
Some of you may remember my article in EFI of the conversion of the Chris Foss
Acro Wot around July 2001 time. The Acro Wot was fitted with a Maxcim 13Y
Brushless motor geared at 3.7:1. It was about that time that the Xtra Wot came to
my attention in various model publications – could I convert this one?
As with all model kits that you build it’s always a good idea to read and re-read
the instructions supplied, I always go through the parts in the kit as well to
familiarize myself with the parts that I will be using – even if some of them may
not get used or modified for an electric conversion of such a model.
Lets Begin To Convert - Fuselage:For obvious reasons the fuselage is where 95% of a conversion takes place, this
model was no different. The basic fuselage is made is the exact way as specified in
the instructions until you get to the firewall installation. My Maxcim 13Y motor
and gearbox was going to weigh about 10 oz. and an engine of Laser 150 size
weighs 2lb or so. It does not take a genius to work out that my conversion would
have a tail heavy tendency to say the least without some good thinking.
As you will see in the firewall pictures a series of blocks have to be made to move
the motor forward to keep weight forward and also avoid having to shorten the
The fuselage with motor mounting arrangement
E.F.-U.K.
31
cowl – thus lightening it, sounds daft on an electric model but nose weight on this
model was going to be needed and I do not add lead in any way shape or form to
any model – unless really stumped!
The 3 dowels you can see inserted into the firewall are to hold the speed controller,
again mounted well forward and in some cold airflow with an air exit behind the
controller going down into the depths of the model, looks fragile with the rubber
bands holding the controller on but it works in practice, the last thing you want
to do is wrap the controller in foam.
The rest of the fuselage is built in the kit specified way, I as you can see added
some lightening holes towards the rear of the model, also I did the same to the
rear flying sections of the model, be sensible with lightening holes, if you are in
any doubt over doing this then don’t, the trick is to lighten the model but retain
strength at all times.
You will have noticed in the Xtra Wot kit that the forward top deck is a fibreglass
moulding, this is very light and aids to the conversion of this model to electric,
this top deck was not made to be removed often, bit I can remove it if I wish. The
20+ cell pack was going to be left in the model. For charging, etc., I made a side
hatch in the model just behind the cowl on the port side of the fuselage.
I should point out to you that the battery is not held in by the top hatch in any
way whatsoever, you will see on the formers the flat plates with Velcro on them,
the battery packs sit on these and then secured down with cable ties or elastic
bands, with such heavy packs I used cable ties on this one. As long as they are
secure and cannot move you will be OK.
The fuselage and tail sections of the model were covered in yellow Profilm, the
cowl and top front decking were sprayed using a Halfords type car body spray to
match the film as close as I could get it.
The tail surfaces of this model are sheet balsa shaped in the normal way, these are
covered in the yellow Profilm. The control surfaces are hinged with normal type
hinges and then I pinned them with cocktail sticks, this is something that I do
with all models, again in particular the larger ones.
Building the wings:This particular section of the article requires very little to discuss, the build is
done exactly as the instructions show utilizing the dual wing servos, I prefer this
on most models in particular the larger types – this model falls into that category!
I also prefer this method from the functional point of view, as with a computer
radio and some of the better non computer sets you can get the ailerons to works
as flaperons to act as landing/braking aids or for in flight aerobatic manoeuvres
whichever you feel you need or both. This also allows the centre section of the
model to house the battery without the risk of fouling the servos in any way that
could lead to a disaster.
32
E.F.-U.K.
The wing and ailerons were also covered in the same yellow Profilm, and the
ailerons are again hinged in the normal way and pinned with cocktail sticks.
Installing The Gear:Once the whole model was built I then began installing the equipment into my pre
prepared positions, you may have your own method of doing this stage of your
models, so I wont go into this stage too deeply.
The rudder servo was a Hitec HS-545BB (high torque), this was linked to the
large rudder by a closed loop system, as many of you know this works very well
on big models particularly on this model where knife edge flight may be used. The
Elevator servo was a Hitec HS-525BB (high speed) and operated the elevator
pushrod supplied in the kit as standard issue. Aileron servos were a pair of Hitec
HS-525BB’s operating standard pushrods.
The main hardware behind the success of this model and many of my big electric
models is the Maxcim Brushless system, this is an American system made by
developed by Tom Cimato, you can visit his website at www.maxcim.com, there
you will see some of the customer applications that have been done with his system.
The motor in this models case is the Max 15 13Y, this is geared through the MEC
monster-box with a gearing of 4.25:1, this is turning a wooden 16” x 10” Zinger
propeller at 6200 rpm on 21 Sanyo 2400 mAh cells. I do intend getting onto the
16” or 17” x 10” APC-E props, but have not yet at time of writing.
The model nearing completion with gear fitted
E.F.-U.K.
33
Another view of the front end, showing the pack installation
The speed controller is the Maxcim 21 cell controller, this is a very well made
controller with BEC facility, counter rotation facility and remote LED display, the
controller is a 35 amp unit but with forced air cooling can handle 65 amps – now
you know why its in the cowl!
This system is very much plug and play when you buy one, they are imported into
the UK by John Swain of Fanfare models, his website is www.fanfare.f9.co.uk
All this equipment that I have listed above plugs into a Futaba 138 PCM Receiver,
I did not use the BEC facility on this model, as I needed the weight of the RX
battery up the front of the model to balance out and give me a good chance of
hitting the CG as marked in the Xtra Wot instructions.
Whenever I use an RX battery I always fit a battery indicator on the model, with
this model as with many of mine I chose to locate it in the cockpit where it can be
viewed very easily.
Setting Up:The models control surface throws were set up as per the instructions, I started
with the maximum throws at 100% of full deflection and then set in 70% of all
these on the dual rates functions in the TX.
The Centre of Gravity position is marked at 112mm back from the leading edge of
the wing at the centre. I picked up the model inverted on the CG as marked on my
fingertips just to see if I was near, I could not believe it I was spot on.
34
E.F.-U.K.
Just to make sure I re checked on my CG balancer rig – again I was spot on. The
model as a matter of interest weighed in at 10 ¾ lbs, this was only ¾ lb. heavier
than the laser 150 powered review article by Neil Tidey last year in RCMW, my
weight of 10 ¾ lbs gave me a wing loading of around 27 oz. per square foot, very
respectable indeed.
Power from the model was very good, the current draw from the 21 Sanyo 2400
cells at full power was 37 amps, the power produced was 811 watts. This gave me
a watts per lb. ratio of 75 watts per lb., not fantastic for such a model but perfectly
flyable.
I did still have the option of re gearing the gearbox, swinging a bigger prop or fit
the 25 cell controller with 25 cells and both of the aforementioned. I decided to
stick with what I had got for at least the test flight of the model.
As a preliminary test I did a range check with 100% success, but I would wait
until I got to the flying field to do thorough power on and off tests before flying.
Flying The Model:It was a Wednesday afternoon when I came to test the model, the model was given
full range checks with aerial down at 50 meters or so, this was with both power
on and off, there were no glitches noticed and the controller behaved impeccably.
It was a nice sunny afternoon with just a gentle NW west here at our field in
Norfolk; the cells were topped up with power for the test.
The electric Xtra Wot in flight
E.F.-U.K.
35
The model on the runway lined up into wind, the throttle was opened very gently
– we were rolling, the big powerful rudder was used to just correct the torque
created by the 16 x 10 prop, easing back on the stick she was off the deck and
climbing, at height I levelled her off, all the trim needed was just 2 clicks of up
elevator trim to get the model to fly hands off. What can you say to that!
The model handles very well with a solid feel to it, I tried out the stall with no
problem, the model in a stall turn kicks over nicely at the top with that big
counter balanced rudder, down from the vertical pull back to level flight and roll
180 to inverted and hold, the model holds nicely with very little pushing to do,
round into an inverted figure 8, roll back 180 to level for a few low slow and fast
passes for the camera, the models slow flying speed in incredibly stable and smooth,
bang open the throttle for a vertical climb – yes vertical with an electric model is
possible, even at this size.
I had set in 6 minutes on the count down timer, this was counting down to zero
and I was still flying. I called landing and brought the model round for the approach,
again no fuss here with a perfectly slow touchdown with no flaps used either, taxi
back and take some more pictures of this fantastic machine. I was happy at doing
another big conversion with success, doesn’t my face just show it!
Paul and his electric Xtra Wot
36
E.F.-U.K.
Birdy
by Mike Payne
Depron is a very interesting material to use, over the last year I have built a few
models and have gained some experience of how to use this foam. I have been
flying this plane from last December, unfortunately Birdy has had to make quite
a few visits to the Vet for help.
My first wing was a straight wing with ailerons stuck on the trailing edge, with a
flat "combat" elevator stuck behind the wing. A fin gave the horizontal stability.
This flew well but after a few weeks I decided to built another plane but with a bit
more style.
This would include ailerons faired into the wing and more bird shaped. The tail
would change to a V-tail supported on a short carbon rod. Birdy was born.
The Mk 2 Birdy under construction
Flying was an immediate success. The pattern was of a plane with very similar
inverted - upright characteristics. Birdy will fly inverted with full confidence,
outside loops from 2m are as easy as loops. The first problem came after multiple
horizontal figure 8's, the wing spar gave way and she dived into the ground. A
long reinforcement was added. Birdy was happy for a few weeks, however while
E.F.-U.K.
37
Birdy wing panel showing failed spar
flying inverted she seemed to see a vole, dived for food and then realised that she
was only foam. A new fuselage was needed. Birdy has had 2 crashes when flying
past other transmitters, this has been resolved by using either a Simprop Indoor
receiver or the new Schulze receiver.
Aileron installation
38
E.F.-U.K.
In Spring a trip to Prague brought back a Mega 16/15/6 motor. A new Birdy was
built with a decent spar. She flew much faster, had a superb climb rate. This Birdy
survived until I went to Middle Wallop, flying in the early mist I did a large bunt
and the V-tail fluttered and broke off, a terminal dive ended this birds life.
A new one hatched complete with glass cloth on her V-tail to increase the rigidity.
I used a ¼" spruce spar to combat the problem of spar failure close to the midsection.
The main problem has been with spar failures, this has often been at the edge of a
centre section joiner / doubler. A balsa wing with film covering seems to have
much greater strength in tension than Depron, the spars seem to have broke
because of a tension failure rather than a compression failure.
I have realised that the spar has to be of sufficient strengthen to withstand all
wing loadings. These foam planes can become great fun and so the wing stresses
go up. My first Depron planes had quite thick wings and a balsa spar was fine
with well curved Depron surfaces.
Having moved to thinner wing sections for greater speed, led to the spar failures.
I have now moved to either using a long central ply reinforcement with or a solid
¼" spruce spar. With this, the join between the tip spar and the main spar becomes
vulnerable.
The ‘tail feathers’
E.F.-U.K.
39
Access to the receiver and elevator servo
Building
Glue - folk have used loads of different glues, including Bison, odourless cyano +
others. I really only use PVA or an aliphatic glue. If you are gluing balsa or ply it
is absorbed into the wood quite quickly especially with warmth, gluing 2 pieces of
foam means that you need a bit of time for the structure to gain some strength.
The glue seems to work by not allowing the parts to separate initially and then the
edge dries and gives the early strength. Further drying makes a good solid joint.
Unless you are in a completely manic building phase try to get to the point of
gluing some major joins and then leaving them to dry overnight.
For the wings it is helpful to have aluminium bars either U or L section - from
DIY stores. I now have both 1m and 500mm long bars to act as clamps. These are
used to hold the trailing edge and LE together.
Cut the wing sheets out, - sand the trailing edge of the lower sheet at an angle to
glue the top sheet to. Stick a 10mm piece of 2mm Depron to the LE. Make the spar
or cut from 1/4" spruce, stick to the Depron, add the tip spars. You can put some
glass cloth over the area of this joint on the Depron sheet.
It may also be helpful to add a tow of carbon on the LE and TE foam joint. Sand the
LE so the top sheet fit smoothly.
40
E.F.-U.K.
E.F.-U.K.
41
42
E.F.-U.K.
E.F.-U.K.
43
44
E.F.-U.K.
The underside of the completed Birdy
Glue the top sheet to the trailing edge and hold with aluminium bars. When stable
add glue to the spar and LE, fold over the top sheet and hold together at the LE
with another set of bars. Then lay down on a flat surface. This should ensure that
the wing is flat.
The following day you can glue the trailing edge for the ailerons. Then do the LE
and wing tip - the wing is almost complete. Cut ailerons from 3, 4 or 5mm foam.
Place this next to the wing, use a 25mm wide piece of glass cloth (1/2oz) and paint
through with acrylic varnish. Dry with a hair drier. This acts as a good hinge.
The V-tail is hinged in a similar fashion.
Make the V-tail from sheet foam. The fuselage is cut out and the sides and top +
bottom parts need to held together, possibly around a blue foam plug until they
have dried. Add an additional bottom sheeting and sheet by the motor.
Add the motor ply support - wound around the motor - tight enough to hold it firm
( use some PVA if it is loose). An option is to add 1/64" ply doubler to the fuselage
sides. Eventually cover the fuselage with glass cloth + acrylic varnish.
The wing needs to have ply supports for the carbon at the trailing edge ( + ply
support against the spar!), and then add a 3" wide glass cloth to the lower centre
wing where the fuselage will join. Glue together.
E.F.-U.K.
45
The wing servos are fixed with clear tape to the lower surface, I fix the elevator
servo below the wing and have a 24-swg wire push rod through the tailplane to
horns on the top surface. This seems the neatest way and avoids the horns getting
damaged on landings. The ailerons do not have the same problems.
Finally paint with acrylic paints, go and fly, try not to annoy too many gulls
please.
The plane uses a 400 motor and 125 x 110 mm (4.9” x 4.33”) Günther propeller. I
think that an ESC that fits on the motor is best, with the connectors fitted directly
to the ESC and then connect the battery to these. This helps keep the motor and
ESC package very compact.
The best batteries are AA pencells, and I use either 8 Sanyo 1700mah Twicells or
Sanyo N-1000 3US cells. These types giving either longer flights or more power,
respectively.
The plan included on the centre pages should be increased to full size by enlarging
with a photocopier from A4 to A3.
Alternatively, you can download a 4 x A4 sheet Adobe Acrobat (.pdf) file or the
TurboCAD plan from my website - www.m.payne.freeuk.com.
The completed Birdy, right side up
If you build a Birdy, please send a photographs and a few shorts thoughts or
comments to the Editor, address on page 4.
46
E.F.-U.K.
TLC from your TLO
by Alan Bedingham
This time some queries on suppression and motors.
Suppression
This from John Anderson:- I will be grateful for some guidance on what values to
use on DC motors bearing in mind some motors come already fitted with internal
capacitors . The MFA kit shows 0.1mfd from each terminal to earth and 0.22mfd
across the terminals. Another set which I think was included with an Xtra ESC
shows 100nF to earth and 47nF across the terminals. These capacitors have
numbers 104 and 473 respectively on them. Are these the same as the MFA but
written differently? - No they're not.
The markings are interpreted as follows -- the first two numbers are multiplied by
the number of noughts in the third number to give a value in pico Farads,
abbreviated as pF. So 473 is 47000 pF, which is .047 mfd, a micro Farad being a
million times bigger than a pF.
Just to confuse the issue a nano Farad (nF) is 1000pF and mfd is also more
correctly written as ì F. Therefore the numbers for the Xtra are 100nF = 0.1ì F or
0.1 mfd, 47nF = 0.047ì F or 0.047 mfd. To confirm these capacitor values, 1ì F (or
1 mfd) = 1000nF = 1,000,000pF = 105
Here's a picture of a typical installation on a 480 motor.
In general, any capacitor is better than none, but I use a set of values that
apparently are optimum for suppression at 35MHz. They are 0.47ì F (marked
474, Maplin part no RA52G) across the terminals and 47nF (marked 473, Maplin
E.F.-U.K.
47
part no RA47D) from the terminals to the can. The 10:1 ratio is important as is
the type of capacitor - they need to work well at high frequencies for best results.
They're also small and a pretty blue colour (!). Don't forget to secure the bodies of
the capacitors to the motor with (say) a dab of Evostick otherwise vibration can
fracture their wires and cause mysterious intermittent interference with associated
brown trouser moments. Don't ask how I know!
What should be used across the terminals with motors where the capacitors are
installed internally?
I fit a 47nF between the terminals to motors that just have two internal capacitors
from brush to can. You can usually tell if they have internal capacitor by the
wires emerging alongside the terminals. Most Cobalt and Neodymium motors
have three internal capacitors and don't need any more added. You can often see
these capacitor through the cooling slots in the can beside the brushes.
7 Cell Motors
These questions from Nick Fitton:- First comment is more of an observation really,
and it is that in most sport E/F applications using highish Kv motors, geared
systems will usually give better results all round - motor longevity, performance
(thrust), duration and system efficiency. Would you agree with this observation?
Yes, I would, if you're talking about ferrite magnet motors. A bit of digging in
your Physics text books will tell you why. The speed of an electric motor is
proportional to the voltage applied, but is inversely proportional to the strength
of the field magnets. So motors with weak magnets (e.g. ferrite) want to spin
faster than motors with strong magnets (e.g. Cobalt), they also have a much
narrower speed band where the efficiency is high enough to be useful. If you do it
right, a geared ferrite can get close to rare earth in efficiency, the limitation usually
being the brush gear on cheap motors that may not like high current and high
speed.
Recently I purchased an Irvine 0507 Cobalt motor. Do you know if this is a Maxx
(MPI) product (it certainly looks like one) and if so which one? Their website lists
a 1507 but not an 0507, If they are one and the same thing I have no problem as
MotoCalc has the constants. If not, do you know the constants.
The constants I've got for the Irvine 0507 are - Kv 1834, Io 3.5A, Rm 49 mOhm. I
may be odd, but I won't buy a motor unless I know the constants, mainly because
I use tools like Electricalc for choosing which motor to use for any project. I know
it's not perfect, but you'll get close to where you want to be, all that's then left to
do is to experiment with propellers to get the performance you want and propellers
are cheap!
This motor is mounted in my Crossfire, on 7 cells with a CAM 8 x 4,5. Performance
is quite good, with the motor pulling 22 - 24 amps. To liven things up a bit, I might
go to a CAM 9 x 5, (I have no room for 8 cells).
48
E.F.-U.K.
Really? Mine has eight cells and they fit easily, maybe because all my packs are
side by side layout rather than end to end with caps. I also think that the Crossfire
is actually a ten cell model based on my rule of thumb that aerobatic models
should have one cell per 35(ish) sq. in. of wing area. Mine has had two rib bays
chopped off each wing and is now much more fun! If I ever build another, I'd keep
it the same size, put wheels on it and use ten cells.
MotoCalc is predicting 30 amps at full throttle. My view is that this motor should
not be subjected to more than 25 amps, but that as it will unload in the air by some
15%, and one is not on full throttle all the time, this should be OK - would you
agree?
No, I would be happy drawing much more current than that, a rough guide being
not to pull more than twice the max efficiency current (22A for the Irvine 0507) so
I would happily set it up for 40A static and reap the benefit of longer flight times
that high power systems and good throttle management always seem to give. I
know it's counter-intuitive, but trust me. If you don't, then think about F5B
'planes drawing 120A and flying for fifteen minutes or more.
How do you measure Rm?
Rm is the armature resistance. In theory, you stop the armature rotating, put a
low voltage across the brushes (an oily fan glow plug battery works well), measure
the current and voltage and then apply Ohm's law. In practice you get a whole
series of different currents depending on where the armature is relative to the
brushes and how hot the motor is getting and you then have to estimate an
average. I prefer to use the motor test feature in MotoCalc or run the motor with
different propellers and fiddle with Rm in ElectriCalc until everything ties up.
Kv (the motor constant expressed as RPM/Volt) and Io (idle current) are relatively
easy to measure as you've no doubt found, but be careful to measure them with
the motor neutrally timed.
(Lastly). I intend to stay as a sport EF modeller only, i.e. 7 to 8 cells max. in
Crossfire type models. Money is limited, but if I were to take the plunge and go
brushless, which one would you go for? Criteria are not less that 10 mins duration
and sport style aerobatics. Because of efficiency considerations, I would like to use
a geared system, or a low Kv motor with no g/box.
Assuming 2400 cells, you've got 144 Ampere minutes to play with, so, for a ten
minute flight , the average current would be 14.4A, peak should be twice that, so
prop for 30A static. A Kyosho Magnetic Mayhem and 8x4 would be happy at that
with an estimated efficiency of 72%. Your Irvine 0507 on an odd size of 8.5x4
(Bolly?) ups the efficiency to 74%. A Jeti Phasor 15-4 on the same 8.5x4 prop ups
the efficiency to 80%. The Magnetic Mayhem costs £25, the Irvine 0507 costs £55
and gives you 2 more Watts into the propeller, a much more durable commutator
and brushes and ball races. The Jeti costs around £175 with controller, gives you
7 more Watts into the propeller and saves what may be a critical couple of ounces
E.F.-U.K.
49
of weight. Please don't take these examples as recommendations, I can't be asked
to recommend motors I haven't personally tried, but you get the picture I hope.
Only you can decide if it's worth going brushless! It's an easier decision when you
get up to the fourteen plus cell range since the cost difference between brushed
and brushless is much less.
Speed 400 Timing
This from Michael Pirie:- I've read about adjusting the timing on re-timeable motors
but have not come across anything on carrying out an adjustment on motors of the
basic 'Speed' type, although I did come across a reference by Bob Smith which
speaks about 'forcing the rotation of the end-bell' which doesn't sound too promising
- but it might be easier than it sounds.
It certainly is. You need to hold the motor very firmly (I use an aluminium plate
to which the motor is bolted and clamp it in a vice) insert something like a pair of
circlip pliers into the two holes in the backplate and twist. You'll need a fair
amount of effort to make it move at first and it will probably go too far, so mark
the original position and the final advanced position before you start. You won't
need more than about 3mm of advance -- against the direction of rotation of course!
This is the set-up I use to recklessly vandalise (sorry - time) Speed 400 motors
using a rather nice tool I got from Hillcott some years ago.
So why bother with this timing nonsense? Well, the main reason is to get rid of
sparking at the brushes which will do two things. - one, produce interference,
and, two, change the commutator from a lovely shiny copper colour to something
more reminiscent of coal; you'll also get more revs for the same current draw.
Timing a 400 motor using a commericcial timing tool
50
E.F.-U.K.
The theory behind it is rather similar to the reason that your car ignition timing
is advanced. The fuel mixture in the cylinder of your car takes time to get burning
fully so you have to light it a bit before TDC, the parallel in an electric motor is
that the current in each of the coils of wire in the armature has to reverse direction
every time the brush moves from one commutator segment to the next and this
takes a small, but significant, time. Advancing the timing gives the coil of wire a
head start so to speak.
Get it wrong and the coil is still trying to change direction when the brush moves
from one commutator segment to the next and the result is a spark. Too little
advance results in sparks at the trailing edge of the brushes and rapid wear of the
positive brush. You can calculate the correct advance if you know enough about
the characteristics of the motor and the operating conditions, but for our purposes,
some simple rules of thumb will get you close enough.
• Speed 400 - advance 3mm measured at the edge of the end bell. Speed 600 about 5mm.
• Use Bob Boucher's rule - advance until the idle current rises by one tenth of
the proposed operating current. Take the Irvine 05/7T as an example, idle
current at neutral timing is 3.5A and you want to operate at 25A, advance
the timing until the idle current rises to 3.5 plus 25/10 = 6A.
• A practical method (if you can see the brushes) is to nail the motor to
something really solid, put on a propeller about 10% less in diameter than
you're proposing to use and increase the advance until you get no sparks
from the brushes. Great for clearing out all the dust and cobwebs in the
workshop and also a good way to get your fingers chopped off, so be careful!
For the real technophiles out there, hook an oscilloscope across one of the
motor leads to act as a current shunt and advance until the ripple is at a
minimum. They'll know what I'm talking about!
Be aware that some rare earth motors have the advance built into the armature
winding and don't have moveable brush housings. Don't try to run them in reverse
- serious pain in the wallet time. Some ferrite can motors (like the Magnetic
Mayhem) are timed for one direction as well. You can tell by measuring the idle
current in one direction and then the other. If it's the same, then the timing is set
at neutral, if they're different, then use the direction that gives the lowest current
and/or highest revs.
You don't need to fiddle with modern sensorless brushless motors, they've still got
to have advanced timing (because they've got coils of wire inside) but the magic
computer in the speed controller does all the work for you.
I think that's enough blathering for this time, next time I want to deal with some
queries about somewhat heavier metal.
Don't let the smoke out!
E.F.-U.K.
51
Letters to the Committee
The following letter was received from Colin Prior.
What ever happened to the "BUILDER OF THE MODEL RULE"?
At several of the Electric Fly-Ins I have attended this year I have been
very surprised and angry at the organisers awarding the First Prize in
scale to ARTF models. A number of competitors are understandably
aggrieved, as I would be, after building a model from scratch or a plan or
completely from a kit. The model built in this manner should always achieve
higher marks than a ready-built, covered and finished model.
In your last issue it was reported that Bob Mahoney's 'Spirit of St. Louis'
was built from a kit. In fact, this was a ready built model costing close to
£800. I have heard fellow-modellers say, "What is the point in entering a
competition if you are going to be beaten by a 'chequebook' model?" The
feeling is why bother next year.
I have been modelling for around sixty years, twenty of them flying electric.
I have won RM Trophy twice, the MFA Trophy, Middle Wallop Scale,
Walsall, Baldock, Hayes, Chester and several others in the last few years.
If I turned up with an ARTF I would declare it and would not expect to
enter it for judging.
If you attend an aerobatics competition with an ARTF it does not matter
as the judging is on flying skills, although at the British Nationals
Championships you always had to declare if you were the builder of the
model.
To make it clear for those readers who are not familiar with the scale competition
arrangements at BEFA fly-ins, the following is the basic system.
Judging is normally undertaken by the BEFA committee members. No
committee member can be involved in the judging for a class they have
entered. The committee can request others to undertake the judging, e.g.
at the Norfolk event the responsibility was passed to the Phoenix Club.
Any number of models can be entered, it no additional charge, by any pilot
who has registered to fly on that day. The model only has to meet two
requirements; that it looks like a scale model of a full size aircraft and
that is seen to fly, by the judges, on that day. That’s it!
Gordon Tarling was requested to consider the letter and the following comments
are made.
I know BEFA has not had a ‘Builder of the Model Rule’ for some time now,
but I do have to agree with Colin's sentiments. Somebody could spend
hundreds of hours building a model from scratch and then get beaten by
an ARTF model from the Philippines! <G>
52
E.F.-U.K.
I know there are people who either don't like building or don't have the
time. So the ARTF's are about the only way these people can get to fly a
nice model, but entering competitions with them and beating scratch-built
models with them isn't really cricket, is it?
Frankly, I'm not sure what the answer is - two classes, one for Scratchbuilt and one for ARTF's? Where would that leave a model like my Storch
where Tim built the airframe and I did all the rest? How about the Moth
I'm doing where it IS an ARTF model, but I'm stripping it down and
recovering it and doing lots of other work besides?
Sorry, but I can't offer a better answer than to have some sort of declaration
signed by the owner / pilot on competition entry to declare whether or not
model is an ARTF and they are then scored accordingly.
I (the Editor) also gave this considerable thought. The following are my thoughts.
The intention at the fly-ins is to run informal competitions that do not
interfere with the general sport flying. Currently no formal recognition is
given to the effort expended in actually ‘producing’ a model for a
competition. However, as Gordon says, this is a difficult nut to crack and
is probably why this is only included in some FAI competition classes.
The BEFA fly-in scale event could be likened to the most informal of club
scale competitions. In my experience of the club scale competitions I’ve
been involved there have been no restrictions on entering ARTF models.,
in fact they have been welcomed as it increases the number of entries..
More formal club scale competitions have a declared marking system. In
these the scoring bias is always towards the flight realism and performance.
In this respect an ARTF is quite probably at a disadvantage as I’ve yet to
see one lighter than a well-designed home-built scratch-built model.
The current competition has no requirement for scale documentation. The
addition of this requirement may be more difficult to comply with for an
ARTF model, but I doubt it is significant. I am sure that, most likely, it
would just deter a few that currently enter from doing so, in future, due to
the extra nausea of creating and producing the required documentation.
Picking up Gordon’s suggestion of running two separate classes, this is a
possibility. However, the main drawback is that at BEFA events during
this last season we only had a few entries per event at best, and on one
occasion only one - the Ryan NYP ‘Spirit of St. Louis’ of Robert Mahoney.
The biggest problem with this is that we would need a significant increase
in the number of entries to make it practical. Unless this were to occur,
there is no merit in splitting the competition.
There is also an additional work load and cost for the organisers if two
separate classes are to receive prizes and/or certificates. This increase in
E.F.-U.K.
53
costs would have to be passed on in the form of any entry fee for the
competitions or an increase in the pilot registration fee.
One possible solution would be to give every pilot, that registers at an
event, a voting slip to select the best Scale and Vintage model in their
view. This has some merits, but history suggests that it takes considerable
effort, by the organisers (again), to get even half the entry slips back.
Further, unless there is some guidance in selecting the winners the system
is just as likely to select an ARTF model as the winner. If guidance is
produced, this deters pilots from completing the forms - Catch 22!
I have stated a few options and the pitfalls of each. I believe that the
Committee shouldn’t have to provide all the answers.
Therefore it is over to you, the BEFA members, to consider this problem
and potential solutions. Please send your comments / solutions to the
Editor at the email or postal address on page 4.
I will ensure that all responses are considered by the committee at the
earliest opportunity.
The NEAT Fair 2002
by John Anderson
Again this year I was able to attend this show that is now probably the biggest in
North America for electric flight devotees. By lunch time on Saturday there were
270 pilots checked in at the Tx compound. This has its downside as the lines for
frequency pegs and flight line access become unduly long. There was a time limit
of 10 minutes put on all pilots after arriving at the flight line whether the battery
was exhausted or not. If the charge did not last 10 minutes then the slot was over
as no second battery was permitted. This kept the lines moving.
To try to minimise accidents slow fly were kept to one end of the flight line and
faster models to the other, which generally worked well. Dual conversion receivers
were recommended after one or two accidents last year which may have been due
to transmitters on adjacent channels being some distance apart on the flight line.
During the course of the weekend two well known electric flyers were presented
with their plaques on being entered into the AMA Hall of Fame. Tom Hunt has
brought about the NEAT Fair after the demise of KRC. He leads his colleagues
from SEFLI to produce the venue and organisation for this vast number of flyers.
He is the designer of Modelair-Tech drives and several kits using only stick balsa.
The other entrant was Dr Keith Shaw. (He is a research professor at Michigan
State University). His scale models are exceptional and flown with skill and
precision and vary from quarter scale to small 020 brushless powered "park flyers".
They join a select band of modellers and the awards are well deserved.
54
E.F.-U.K.
King Crimson by Keith Shaw. 4 x Astro 035G. Well known Horton inspired flying wing.
Also a recipient of a plaque marking his entry into the AMA hall of fame.
Now on with the show itself. The weather was pretty kind on Friday and Saturday.
Occasionally a strong gust would sweep through Pleasant Valley taking with it
sun shades and canopies that were not firmly fixed to terra firma. These conditions
only occurred two or three times, but without warning, from midday onwards
causing severe turbulence and catching some models with disastrous results.
Sunday morning saw conditions reminiscent of UK at a weekend. Light rain and
low cloud. For an hour or so it brightened up but before midday the heavens
opened and this was enough for the few remaining to pack up and head home.
It is worth mentioning that this show is run like BEFA events. If you have correct
insurance then you can fly. The AMA has no schemes to assure that pilots are
competent to fly, the only restriction placed on pilots is that the model must have
successfully flown before the event.
The traders line was almost the who's who of electric flight in North America. I
counted at least 25 stalls but along the pilots line there were several "cottage
industry" manufacturers showing their wares.
One new trader to the show is a machine shop owner from California displaying
gear drives called Inner Demon and Mini Demon. I have copied the picture off the
pamphlet (overleaf) which shows the size of each compared with a quarter dollar
piece. The workmanship is first class and substantial.
The Mini Demon is designed for motors with 5/8” (16mm) bolt hole spacing which
includes the 400/480 range and equivalent brushless sizes. The Inner Demon takes
motors with 1in (25mm) bolt hole spacing and can handle 1200W of power using
E.F.-U.K.
55
Inner Demon (left in both shots) and Mini Demon (Right)
two brushless motors. Have a look at the web site for more information
(www.InnerDemon.com)
With so many pilots I expected to find a glut of new and exciting models. Many
flown during the demonstration at lunch time each day had been displayed before.
One new model was by Gary Wright from Florida. This is in the mould of fun fly
models with wide chord and light weight. Gary is a very skilful pilot so I expect he
got a lot more out of the model than the average flyer. Kits are available at around
$100, check out his web site at www.gwmp.net. There were several others flying
E3Ds at the meet.
Hobby Lobby from Tennessee showed a selection of ARTFs mostly using Jeti
Phasor 45/3 motors. The eye catching one from my perspective was the Bucker
Jungmeister (sorry no photo). This has fibreglass fuselage with wooden wings
Dave Grife’s quarter scale Mystery Ship.
Weighs 17lbs and is powered by Astro 60 with superbox on 40 cells
56
E.F.-U.K.
and tail feathers. It flew on 10 cells with 12” x 8” APC'E' propeller. They also have
a Tiger Cat which looks to come from the same source as the one SoMoSo retail.
More on their web site www.hobby-lobby.com
The ornithopters from Kinkade brought some light hearted flying to the slow fly
end of the line. These 'birds' use Speed 300 motors geared to a cam which through
links to each wing causes the wings to flap and generate lift. They are great to
watch but rather pricey at around $200. RCMW has a review in the October issue.
Since I began this report I have received my latest UK magazines in which many
of the models at NEAT were featured having been shown at earlier fly-ins in USA
and Canada.
The large attendance did not detract from the convivial atmosphere that has been
a feature of the NEAT meetings. Whoever you find yourself next to, be it as a
spectator watching the flying or at the bar afterwards, you are always treated as
a friend.
I would guess about 200 attended the buffet dinner on Friday evening. This year
it was held at a restaurant about 14 miles from the flying site. Even the Americans
thought this was rather a long way, but it did have a bar!
Keith Shaw and Bob Kopski walking together after Bob had giver a demonstration of
“Galloping Ghost” radio control.
E.F.-U.K.
57
E3D of Keith Wright, the designer.
Geared Hacker B40 on 10 cells. Has 48” span and weighs 57 ozs.
Birds at Rest. The Ornithoptors from Kinkade R/C in Florida. Good fun factor.
58
E.F.-U.K.
Beautiful Sikorski S38 powered by 2 x Astro 05G motors driving 10 x 6 3 blade props on
8 cells. Weighs 91/2lbs. ROG from short grass.
Nick Ziroli with his scaled down Rudder Bug.
56in span with cobalt 05 + 3:1 gear on 7 cells. Covering is silk with Airtronics radio.
Plans are expected to be published in late 2002.
E.F.-U.K.
59
I can never resist taking a photo of this large B17. Originally built by Joe Basher (he
was a B17 pilot in the war) but now owned and flown by Dave Barron. 10.5ft span with
4 Astro 05s direct drive on 32 cells. Dave will fly the model 3 or 4 times each day when
the weather allows. Says has over 200 flights logged
This PV4Y “Privateer” is converted from a Multiplex Cargo by Everett Rubendunst. The
fuselage has been inverted to provide the high wing seat. Everett said he trimmed a little
from here and there and added a little here and there to produce this very good
rendition. Standard Cargo power system provide good slow scale like flight in the
capable hands of Dave Barron. Don Belfort provided the initial urge.
60
E.F.-U.K.
Nick Ziroli picked up this Kyosho Lear Jet a couple of years ago.
Standard fan system with two packs of 7 cells 2400.
1914 Hass-Von Dickenson powered by an Astro 05G on 7 cells,
which flew in calm air, wing loading 4.39 oz. /sq. ft.
E.F.-U.K.
61
Electric Eighty
by Brian Squelch
I'm always impressed by the skill and techniques shown by other modellers.
However, I'm sure that the 'modelling stars' are outnumbered by the 'run-of-themill' types and being one of the latter I thought that a lower level article might not
come amiss. For interest, I'm a member of the Tunbridge Wells Model and the
Tonbridge Radio Flyers Clubs.
I don't want to lower the tone too much but I'm starting from the point where I
had done a bit of I/C modelling, mostly with balsa rather than ARTF and although
I am an MIEE my knowledge of electrics and electronics as applied to electric
flight was about zero.
I had looked at the Electric Page in the BMFA News, and was grateful for that,
but I knew nothing of the 'rules of thumb' such as 50 watts / pound or wing
loading of 20 - 30 ounces per sq. ft. Even now I haven't yet got into MotoCalc.
As always things seem to happen by accident. Having made a bit of a rash purchase
at the model shop I had to renegotiate our financial arrangements. At the time my
credit status was good, and after an indecently brief period, I deemed it an
appropriate moment to buy a few electric knick-knacks. The shopping list seemed
to grow rapidly and pretty soon I was running out of credit but at least I had a few
things with which to get started.
I have always fancied a twin-engined model and had the idea that electric power
would be a relatively painless way to satisfy this ambition. Having an old Precedent
High-fly glider to hand I had a go at modifying it. The wings were stretched and
engine mounts and ailerons incorporated.
The underside of the fuselage was modified to house the battery. It flew - just, but
the wings were of far too high an aspect ratio for the structure. After a reasonable
number of flights, and in a moment of rashness, too much up-elevator was applied
and the inevitable happened - the wings folded. It may be noted that in these
circumstances the plane plummets rather than flutters down!
Clearly I needed a much deeper and potentially stronger wing. It occurred to me
that the wing of a Super Sixty was deep enough to form the basis of a strong spar.
Moreover, it was a plane that could be flown off the ground and landed rather
than hand launched. Conveniently, a friend of mine, Roan Logan, had, for reasons
best not gone into, a couple of sets of plans.
The fuselage was a simple structure mainly of 6mm balsa and the wing was straight
forward with a constant chord. Thus it seemed suitable for a scratch build over
modified plans.
The reasoning / modifications thought necessary are described below.
62
E.F.-U.K.
Fuselage:
-
Fit a ply bed in the front part of the fuselage to support the battery. This
would need to be fairly long to allow for C of G adjustment.
-
Delete the engine mount and round out the front of the fuselage. The top
of the nose section was to be removable to allow access for the battery.
-
Strengthen the front end of the cockpit to support the heavier wing.
-
It wasn't going to be the fastest thing on the ground, so to help keep
control, a steerable tail wheel would be fitted. Furthermore, to reduce the
chances of 'ground-looping' the main wheels were shifted aft by about 12mm.
-
To accommodate the new tail wheel arrangement, the tail plane was raised
and incorporated in the fuselage. On the original design it was held on
with elastic bands.
Other than the above, the fuselage was pretty much standard. The servo tray was
in the same place as for the i.c. version and sat over, and towards the back-end of,
the battery. Now it would carry the motor controller instead of the throttle servo.
The small battery for the radio control was retained for security and to energise
the model without the presence of a main battery. The tray lay-out was arranged
to keep high and low current areas as separate as possible. The aerial and receiver
The revised nose design of the Electric Eighty
E.F.-U.K.
63
The revised tail arrangement
using micro-amps were to the rear, the servos using milli-amps in the centre and
the heavy-duty battery and controller currents to the front. So far this seems
satisfactory without any further screening.
Wing:
64
-
To carry the expected extra weight of batteries and motors, it was thought
to be prudent to increase the span from the standard Super Sixty to eighty
inches. To keep the alliteration going the model just had to be called the
Electric Eighty.
-
The upper and lower elements of the main spar would, in the centre section
of the wing, use 6mm spruce rather than balsa. Standard lengths were
used, 36 inches as I recollect. The outer part of the wing would continue
to be of balsa construction.
-
The maximum relative movement of the upper and lower elements of the
main spar would be at the outboard ends. Accordingly, to construct the
strongest possible beam, the webs joining the upper and lower spruce
elements were concentrated at the outboard ends. This would lock the
two elements together most rigidly. The webs were made from ply rather
than balsa and were epoxied in place both on the front and rear of the
main spar.
-
In the centre of the wing, between the engine mounts, the lower part of
the 'D' section between the spruce spar and the leading edge was made
from a 6mm balsa sheet. The adjacent engine mounting bays were of 6mm
E.F.-U.K.
ply. The remainder of the construction outboard of the motors was fairly
standard.
-
The centre section located above the fuselage, and behind the secondary
spar, was built on 3mm ply. This was to strengthen the wing where it
rested on the fuselage.
-
A hatch was made in the underside of the wing between the main and
secondary spars for wiring access. Plastic tubing was installed through
the wing ribs from the hatch bay out to the engine bays on either side.
-
This was to carry both the power and the aileron wiring. The wiring runs
are close together inside the tube for about 30cm but the power does not
seem to cause interference to the aileron control.
-
Plywood, 6mm sheet, was added between the main and secondary spars
behind the engine bays. These pieces were cut to carry aileron servos.
-
Ailerons, about 70cms long and 6cms wide were let into the trailing edges
of the wings. These are hinged at the upper surface of the wings and
directly coupled to the servos behind the engine bays.
The port motor, mount and securing arrangement
E.F.-U.K.
65
The rear of a motor mount
-
The ailerons are probably rather larger than need be, but my test pilot,
one Peter Beeney, told me at an earlier experimental stage that the originals
were not worth zip. The next time I thought I would make them the size of
Dumbo's ears.
Now, like Mr Kipling's cakes they are exceedingly good.
That pretty much covers the changes to the wing. Since the wing uses uncut
spruce elements at its centre there is of course no dihedral.
Engine Mounts:
-
The ply wing plates were drilled for captive threads to carry Olympus
mounts beneath the wing. After a good deal of experimentation these were
superseded by direct drive 600 ferrite motors using 8" x 4" Slim Props.
-
A short length of round plastic tube, about 7mm OD is glued into a piece
of square plastic tube about 65mm long. The square tube is drilled to suit
the positions of the captive threads and the round tube is cut to leave
about 5cm protruding in front of the wing.
-
The ferrite motor is lightly taped in place on the protruding plastic tubes.
A short length of heat shrink, 72mm tube, is slipped over the motor and
plastic tubes and shrunk down to give a snug fit.
This arrangement seems quite firm but in the event, heaven forbid, of a heavy
landing, the plastic tube breaks rather than the heavy ferrite motor tearing a
section out of the wing.
66
E.F.-U.K.
The power and servo connnections to the wing
Powering, Props and Electrical Connections:
The electrical motors used are cheap ferrite standard 600 motors. Various sizes of
propellers, both geared and direct drive have been tried. The latest arrangement
is using 8" x 4" Slim propellers, direct drive.
Sanyo 2000mAh cells are used. Combinations of between 7 and 12 cells were tried
in parallel and series configurations. However, nothing seemed to give enough
power and / or duration.
A series configuration was preferred since a failure of the circuit would not produce
an imbalanced flying condition. The motors, which were nominally 9.6v, required
8 cells to give a reasonable performance. Thus, to connect the motors in series a
different controller capable of handling 16 cells was required. A Fleet controller
for up to 20 cells is now installed. This set-up gave an acceptable performance.
My inexpensive charger is capable of mains fast charging up to 9.6 volts so two,
double 8 cell packs, can be prepared fairly quickly.
Checks with a watt-meter indicate that the 19.2v, 16 cells source, delivers, through
the controller, about 440 watts at 25amps to the motors. Presumably, losses in
the controller and watt-meter account for the loss of a few watts. The current
E.F.-U.K.
67
falls-off reasonably quickly from a high initial peak but after taking-off the model
is throttled back in any case to reduce the current drain. It will fly comfortably on
two thirds throttle estimated to be a load of about 15amps.
The take-off run is about 20 metres in reasonably quiet conditions. Flight duration
is 5 minutes or so thus allowing a few trial approaches before landing. It has
flown for a little over 8 minutes but with not enough power left to taxi-in.
Now that reasonable flight has been achieved, how does it sit with the 'rules of
thumb'?
Weight:
- Airframe =
5lb 10oz
- Battery
=
2lb
3oz
Total
=
7lb 13oz = 7.813 lb
=
125oz
Wing area
=
77” x 10.4” = 800.8 sq in = 5.56 sq ft.
Loading
=
125oz / 5.56 sq ft = 22.5 oz / sq ft.
Power to Weight =
440/7.813 watts/lb
=
56.3 watts/lb.
Thus after considerable experimentation the inescapable 'rules of thumb' have
been vindicated yet again.
The completed Electric Eighty
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E.F.-U.K.
Electric Piggyback
©©by John Stennard
I’ve had great fun flying my 920mm (36¼”) span Scorpio threedee400 and my
review of it was published in Quiet &Electric Flight International (Q&EFI) as
was my follow up detailing its conversion to AXI brushless power.
With this AXI motor and an 8 cell pack of the latest HV 4/5 AVP 1700 NiMH cells
I reckoned that there was enough power to spare for lifting a small RC hand
launch glider aloft, piggyback style.
Not only did I think this would be fun but also an ideal way to give novice pilots
some useful extra training.
This is just a summary of the system as a full feature on it was published in the
December Q&EFI.
A suitable small hand launched glider was available from Flitehook. It is an ARTF
model of 980mm (38½”) span called the Zip. Assembling the Zip was problem free
and test flights showed it to be very easy to fly, and the AUW is 183g (6.5oz).
As can be imagined the pylon mount for the glider took a while to perfect. It
involved a number of modifications before the system was safe and reliable. The
pylon is constructed from 1.5mm ply plus 6mm dowel rod and balsa.
The mount fitted to the threedee400
E.F.-U.K.
69
The release mechanism uses a servo operating on an auxiliary channel (in my
case channel 5). The movement of the output arm releases the two rubber bands
that hold the glider in place on the pylon.
The test flight program initially involved flying the threedee400 with the pylon in
place. This replicated the post launch situation and was fully successful.
The second series of test flights took place with the glider in position for both take
off and landing. This replicated a non-functioning launch situation. These flights
resulted in several changes to the pylon to stop the glider rocking in turns.
The final test was to release the glider in flight. This test was successful and the
piggyback system has now been operated on numerous occasions. The threedee400
climbs very well with the Zip on top, I guess the extra wing area more than
compensates for the extra weight.
I am sure the brushless powered threedee400 could easily lift a larger and heavier
glider. Piggybacking is an easier option than towing although I am confident that
the use of an electric powered ‘tug’ is entirely practical.
This has been an interesting project and demonstrates yet again how far electric
power has come.
70
A close-up of the piggyback mount in use
E.F.-U.K.
The combination takes to the air
Have you got an electric powered model that others might be interested in hearing
about. If so, please send a photograph (or more) a details to the Editor, using the
contact details listed on page 4.
E.F.-U.K.
71
R.O.C.C.A.
by Mike Pitchers
There was quite a lot of interest in "Rocca" last Sunday at Pillerton Hersey, so I
thought that you would like to know more. "ROCCA" is an acronym for Remotely
Controlled Camera Carrying Aircraft. It was started as a design project by my
Grandson while at school (with a lot of help from his Grandad).
It was based on the general dimensions of "Heron" and build around the very
efficient "Master Airscrew" power train. It is 5' 6" (2 m) span and 4' 10" (1.5 m)
overall length, the wing chord is 9" (23 cm).
The ROCCA airframe completed, but uncovered and covered
The build weight was kept down as much as possible without compromising the
airframe strength. In flight it has exceeded expectations; it will take off with the
camera, a Canon Ixus weighing 8ozs. (227 g), on board and without the camera
has thermalled in good lift.
Another view of the covered ROCCA
72
E.F.-U.K.
“Rocca's" first job was to carry out an aerial survey to see if it was possible to find
my "Sportwagon". The "Sportwagon" a vintage design which suffered radio (?)
failure and disappeared into very deep bracken, many hours of searching has
failed to locate it. I was not surprised to see nothing but bracken, I had expected
that the aircraft had dived through the canopy and would be out of sight.
The missing Sportwagon (before the disappearance)
This is the foam mount
used to hold the Canon Ixus
digital camera in position.
This camera is a 2M pixel
camera giving images of up
to 1600 x 1200 pixels.
The camera is mounted
upside down, so that the
trigger button is easily
operated. It is held in place
by a hook and loop strap to
allow speedy removal.
E.F.-U.K.
73
Above is a photograph of Newtown Linford village & part of Leicestershire. Below is a
shot of part of the Pillerton Hersey flying site showing the cars (pits) and patch (just).
74
E.F.-U.K.
Left - a more
complete view of
Pillerton Hersey
patch with
several
modellers stood
around the
bottom corner.
Below my house
and garden.
E.F.-U.K.
75
Conclusion:The power from the geared Maxcim 13Y brushless motor is quite astonishing as
some of you may be aware, this model at the present is not quite as powerful as
my smaller Maxcim 13 D powered Acro Wot, but then my Acro has 103 watts per
lb. and climbs at 90 degrees from take off with a 45 amp current at full.
I am very confident that with a few more cells and re gearing of the MEC Monster
box I can push the 100+ watts per pound mark, this is the first Xtra Wot I have
seen fly and as you might expect this must be the first electric one ever!
That’s all for now from me - Paul Cook. Should you wish to contact me on any
relevant details with this model you can Email me at [email protected].
JUNE 28TH & 29TH 2003
at North Weald Airfield, Essex
(Just off Junction 7 - M11 motorway)
The largest RC Model Show in the South
Flight Line directed by The Ghost Squadron
Electric Model Display Pilots welcome, pre booking required.
Please contact us if you are interested in displaying your model.
Other attractions include:- Large Model Boat Pool,
Model Car displays, Over 70 Model Trade Stands,
Gigantic Modellers Bring & Buy, Bar, Refreshments, Saturday Night
Entertainment plus lots more!!
See all about the 2002 Show on our web site
www.wingsnwheelsspectacular.com
Tel./Fax: ++ 44 (0) 1480 462265
email: [email protected]
Designaction Limited, Wings & Wheels, PO Box 284, HUNTINGDON. PE28 9AE
76
E.F.-U.K.
FOR SALE / WANTED
Member's Sales & Wants
For Sale on behalf of the estate of the late Sqn Ldr Ken Wood, MBE. The models
are all fully built & shipping is difficult, but delivery and/or viewing can be arrange
at any of the BEFA fly-ins or the AGM. For more details (or digital photographs),
contact Jan Bassett on 01935 472743 or [email protected]:
• Goldberg Electra powered sailplane with modified nose shape (78” span
single-piece wing of 663 sq. in.). Fitted with 1 Hitec HS-80 & 1 Futaba
S143 servo. The motor mounting is designed for a Keller 22/12 motor, but
would fit a 600 motor & compact gearbox with little or no modification.
Covered in SolarFilm, the fuselage, fin & wing centre are red, with the
tailplane, elevator & rudder in white and yellow outboard on the wings.
Intended for 7 Sub-C cells, but would take 8 Sub-C or 10 4/5 Sub-C. Price
for a quick sale to a good home at £40 ono.
• Goldberg Electra powered sailplane with modified nose shape as above.
Fitted with Fleet FPS-24A speed control, Micron Mini Rx and 2 Fleet
FPS-18 mini servos. Covered overall in Fibafilm with the fuselage, elevator
& rudder in white and the wings, tailplane & fin in red. Intended for 7
Sub-C cells, but would take 8 Sub-C or 10 4/5 Sub-C. Price for a quick
sale to a good home at £40 ono.
For Sale by Neil Stainton, telephone him on 01926 314011 or email at
[email protected]
• New Aveox 27/26/2Y high efficiency motor - £69
• New Jeti 40-3P brushless controller - £59
• New Jeti 70-3P brushless controller - £78
• Ceto 35Mhz receiver with 2 WES Technik 2.4g servos (see photograph
below). Complete weight is 10g. Rx xtal not included - £60
E.F.-U.K.
77
For Sale by Eric Cable, the following motors which are boxed and unflown.
Contact Eric on telephone 01935 478974 (Yeovil).
• Plettenberg HP 200/20/12 motor - £75
• Astro 05 FAI, 6 turn motor, geared 2.2:1 - £95
• LRP Super 400 - £25
For Sale by Dave Chinery, a Aveox 1406-2Y and controller - £120 ono. Contact
him on 020 8573 4687 or at email [email protected]
For Sale by John Deeming, a considerable number of electric flight motors, too
numerous to list, including MaxCim, Astro, Graupner and Permax. Most are boxed,
new and unused. Also some miniature 35MHz receivers and a Multiplex ‘Brick’,
all boxed, new and unused. Please telephone John for details on 01395 233102
(Exmouth, Devon).
Wanted by the Editor (contact details on page 4) any of the following:
• Articles.
• New products.
• Event write-ups.
• Photographs of models (preferably with dimensions, equipment installed
and flight performance please).
• New items of interest for inclusion in this magazine.
• Photograph prints supplied will be returned if you supply a return address,
unless you specify otherwise.
• Digital photographs should be at least 1000 pixels wide, in colour and
uncompressed wherever possible.
Requests for inclusion in the For Sale & Wanted pages can be made by email, post
or by telephone, to the Editor using the contact details on page 4. Entries can also
be submitted on-line from the For Sale & Wanted page on the BEFA website at
www.befa.org.uk
If you wish to have pictures included with your for sale or wanted entry, post
photographs, or email graphic files, to the Editor. Graphic files should be in colour
and uncompressed were possible.
Adverts will be included in both E.F.-U.K. and on the BEFA Website unless
instructed otherwise.
78
E.F.-U.K.
Electric Flight Calendar
If you would like details of your event to appear in these pages please send full
details to the Editor EF-UK, contact details on page 4. For last minute info check
out the events list onthe BEFA website at www.befa.org.uk
Dates, times and, even, locations of events can change at the last minute. You are
strongly advised to check on events with the given contacts before setting out on
your journey to any event.
You are asked to please check with the organisers of non-BEFA events for their
qualification requirements before the event.
All BEFA flying events require proof of BMFA or equivalent insurance
to fly. Additionally, all models must have been satisfactorily test flown
prior to the BEFA event to fly - NO TEST FLIGHTS ON THE DAY.
The BEFA has not yet set minimum qualifications to fly at our events, i.e. no
BMFA certificates are required to fly. Currently all that is expected of pilots is a
reasonable level of flying competency.
January 2003
11th
Unfornuately, due to lack of interest, the BMFA Northern
Area Indoor fly-ins for this winter have all been cancelled.
March 2003
9th
BEFA Annual General Meeting - see the details on page 7.
June 2003
28th / 29th Wings and Wheels Model Spectacular at North Weald Airfield,
Essex. All the usual attractions of this annual event. Please see the
advert on page 72 for more details.
July 2003
27th
Bath SpaRCS Fly-In at Colerne. Just to let you note it in your
diaries, more information to follow.
August 2003
16th/17th
Greenacres Fun Fly at Walsall Airport. Cost per frequency £2.50.
The usual arrangements for camping, trade, etc. For further
information contact Andrew Moult on telephone 01922 724311 or
email [email protected] or alternatively Peter Hubbard,
on 07754 058872 or email [email protected]
E.F.-U.K.
79
New to ELECTRIC FLIGHT?
START HERE . . . . .
You may be taking up Electric Flight for the first time, you may be converting
from another discipline. Whatever your situation, help and advice is available.
BEFA has prepared an information sheet which details further sources of
information which you may find useful when just joining the hobby. To receive a
copy, please send a Stamped Addressed Envelope (SAE) to Robert Mahoney, address
on page 4.
BEGINNER'S GUIDE
A Beginner’s Guide to Electric Flight is available, which explains many of the
'Mysteries' of Electrics’ and will, hopefully, set you off on the right foot. Please
send £3.00, per copy required, to The Editor of EF-UK at the address on page 4.
Please add £1.00 extra for overseas postage and remit in Sterling, cheques payable
to BEFA.
TECHNICAL HELP SERVICE
Technical help is now available again for the use of all members. We regret that
no telephone service is available, but all questions in writing (or email) will be
answered by our new Technical Liaison Officer (TLO). Please refer your queries
to our TLO, to the postal or email address on page 4. Please ensure that you
include an SAE for a reply.
CONNECTIONS SERVICE
Requests are frequently received from members who wish to be put in contact
with other members living in the same area. The easiest method of doing this is
to place a free 'wanted' advert in the classified section of this magazine.
Alternatively, a request may be made IN WRITING to the Membership Secretary
who is allowed to divulge such information to members ONLY. Please supply as
much information about your location as possible and please remember to include
an SAE for your reply.
B.E.F.A. MEMBERSHIP
Membership of the Association is open to all members of the BMFA. Those who
are not members of our national controlling body may only subscribe to EF-UK
with no other benefits of membership. Overseas members are very welcome and
will be classed as full members if they belong to their own national controlling
body.
CONTACT
For full details, please send an SAE to the Membership Secretary (address on page
4) requesting a membership application form. Those with Internet access may
visit the B.E.F.A. website at http://www.befa.org.uk, where you will find all the
membership application form & information you should require.
80
E.F.-U.K.
MAIL ORDER MODEL SUPPLY
GOLD PLUGS Ideal for Speed 400/600
2mm plug 75p; cuts into two giving one plug/socket
2mm solder socket 43p. 2mm plug and a 2mm socket £1.15
Lightweight 2mm plug and socket 55p; Max 15A motor current draw
Spares. 2mm light plug 40p. 2mm light socket 20p
Pack of red/black shrink: 3.2mm or 4.8mm 50p
GOLD PLUGS 600 or larger motor
4mm plug 90p; cuts into plug/socket. Very low resistance
4mm hollow plug and a separate 4mm solder socket £1.15
Spares. 4mm hollow plug 85p. 4mm solder socket 43p
Lightweight 4mm plug and socket 75p; Max motor current 35A suggested
Spares. 4mm light plug 55p. 4mm light socket 25p
Pack of red/black shrink: 6.4mm £1.25: 4.8mm 75p
Providing that you bear in mind the suggested amp ratings all the 2mm and 4mm plugs are
interchangeable. All fit any of the same size.
EXTRA FLEXIBLE WIRE. 0.5mm2, 129 strands, Max 10A, 35p/metre
Red or Black or White. Park Flyers etc. or servo extensions.
EXTRA FLEXIBLE WIRE
Supplied in packs of 1 metre of red and 1 metre of black, i.e. 2 metres of wire
0.75mm2, 196 strands; ideal for weight saving, Max 15A, £1.00/pack
1.00mm2, 258 strands; ideal for weight saving for speed 400, Max 19A, £1.40/pack
1.50mm2, 378 strands; ideal for speed 400, £2.00/pack
4mm2, 1036 strands; £3.50/pack
SILICONE INSULATED WIRE. Pack of 1 metre of red and 1 metre of black
1.5mm2, 378 strands. £2.50
2.5mm2, 651 strands. £3.00
All wire can be cut off the roll, in longer lengths if required.
CELL HEATSHRINK metre lengths
25mm 50p; suits single AAA or AA cells or any same size
48mm 75p; suits single sub C cells/sticks or packs of dumpy 600
65mm 85p; suits 1700 or 2000 packs, also RC oblong sticks etc.
94mm 95p; suits double deck packs (1700 etc.)
All sizes layflat width, supplied in clear. 48mm available in opaque blue also.
WIRE HEATSHRINK metre lengths
1.6mm 50p; 2.4mm 60p; 9.5mm £1.00. Black only
3.2mm 75p; 4.8mm 80p; 6.4mm 95p. All in red or black.
ALL ORDERS PLUS POSTAGE: 60p UK; £1.10 Europe; £1.70 World
M. E. DONKIN, 37 WYDALE ROAD, OSBALDWICK, YORK, YO10 3PG
Tel/Fax 01904 414738. Mobile 0771 202 8329.
E-mail: [email protected] or [email protected]
All messages - an attempt will be made to contact you. (I work shifts)
Computer faxes must send start signal before my fax will respond!
E.F.-U.K.
81
B.E.F.A. Sales
BEFA Round, Coloured Rub-down Decals - 50p each
BEFA 2000' Millennium Decals - £1.00 each
Back Issues of EF-UK - No's 38, 40, 41, 44, 52, 53, 55 to 63 (inclusive) at £1.00
each for BEFA members, or £2.00 each to non-members. Issues 64 to 70 are also
available to BEFA members at £3.00 each, or £5.00 each to non-members. These
prices include UK P&P, overseas rates on application.
Please Note these are the ONLY back issues now available.
EF-UK Index. A comprehensive index of EF-UK from issue 28 to 59 is available
by sending a £1 coin to cover copying and postage cost.
Binders:- are available to hold eight issues of Electric Flight U.K. Produced in
dark blue with gold lettering on the spine, these cost £4.50 each including U.K.
postage. Please add £1 for European postage and £2 for Worldwide postage.
Sweat Shirts & Tee-Shirts: Stock of these is now almost all gone - please
contact Robert Mahoney regarding remaining stock, sizes and prices.
Please send all orders to Robert Mahoney at the address on page 4.
PLEASE REMIT IN STERLING ONLY,
WITH ALL CHEQUES MADE PAYABLE TO B.E.F.A.
Advertisers Index
BEFA Sales .................................................................. 82
Buzzflight .................................................................... 30
E-Zone ...............................................Inside Front Cover
Fanfare ............................................... Inside Back Cover
For Sale / Wanted ........................................................ 77
Mail Order Model Supply............................................ 81
New-2-U ........................................................................ 8
Traplet ............................................. Outside Back Cover
Wings & Wheels .......................................................... 76
E.F.-U.K. advertising rates are £20 per full page, £10 per half page, per issue.
Please contact the Editor for further information (see page 4).
82
E.F.-U.K.
– MAIL ORDER –
SPORTS ELECTRIC FLIGHT
FANS AND GEARBOXES
www.fanfare.f9.co.uk
GEARBOXES
FANS
Morley ‘Jet Elec’ Fan .............................. £15.00
Adaptors for
480 & 410 motors .................................... £3.00
WeMoTec MiniFan 480 .......................... £28.00
MidiFan for 540’s, 600’s 930’s .............. £38.00
MOTORS
WEP Turbo 10 ........................................ £55.00
Speed 500 E Race ................................. £13.00
Speed 600 8.4v BB SP .......................... £15.00
Speed 600 8.4v Race ............................ £18.00
Speed 650 9.6v BB Race ...................... £33.00
Speed 700 ............................ £14.00 to £22.00
Neodym ..................................... £38.00
RE 380 / Rocket 400 ................................ £4.50
Speed 480 PB .. £14.00 BB ................ £21.00
Pro 400 ............... £5.00 Pro 480 .......... £7.00
Master Airscrew 2.5, 3, 3.5:1 ............... £16.00
TAB Inline 2.65 540/600’s .................... £40.00
TAB Inline 2.08 & 3.05 480’s ............. £40.00
TAB Inline 2.1 700’s .............................. £50.00
Mini Olympus ....... £8.00 Olympus ...... £12.00
MOTORS / GEARBOXES
MFA 2.5:1 N.I.L. with 540 ...................... £21.00
Speed 400 FG3 ..................................... £17.00
SpeedGear 400 4:1 Inline ...................... £35.00
SpeedGear 480 3.45:1 .......................... £48.00
SpeedGear 500 2.8:1 ............................ £40.00
SpeedGear 600 2.8:1 ............................ £41.00
SpeedGear 700 2.7:1 9.6v .................... £60.00
SpeedGear 700 Neo .............................. £82.00
Mini-Olympus & RE380 .......................... £12.00
Olympus & 540 ...................................... £19.00
Robbe 410/35/45 ................................... £36.00
MAXCIM BRUSHLESS
Max Neo 13Y 1430 rpm/v ................... £160.00
Max Neo 13D 2470 rpm/v .................... £160.00
21 Cell Controller ................................. £140.00
25 Cell Controller ................................. £180.00
Superbox 1.6 to 4.28:1 ......................... £50.00
Monsterbox 4 to 6.8:1 .......................... £60.00
Motor Mount ........................................... £12.00
CHARGERS
Speed 1 Pulse / Pk
Det 4-8 cells ........................................... £27.00
Speed Ex Digital
as above with discharge ...................... £55.00
Simprop 25 cell .................................... £100.00
PROPS
M.A. Folding
12x8 ............... £14.00
15x12 ............. £15.25
M.A. Wood Electric
10x6/10x8 ........ £4.00
11x7/11x9 ........ £4.25
12x8/12x10 ...... £4.50
13x8/13x10 ...... £5.00
Carbon Folders
7x4 ................... £6.00
(Perkins)
8x4.5 ................ £6.00
11x8 ................. £9.00
Slimprops 8x4, 8x6, 9x5, 9x6 .............. £3.50
APC Electric
6” - 12” dia. .............. £4.00
(full range available) 13 ” - 18” dia. ..... £5 to £10
Selection of Graupner & Aeronaut
folding & fixed props.
Wheels, Wire, Servos, Fuses, Caps,
Powerpole, 4mm & 2mm gold conns.
FANFARE • 18 HILLSIDE ROAD • TANKERTON • WHITSTABLE • KENT • CT5 3EX
‘Sports Electric’ Helpline - Phone / Fax: (01227) 771331 - E-mail: [email protected]
Now online at - www.fanfare.f9.co.uk