Small Thrust_QEFIMAR11.indd

The J-Power Typhoon has
a very fine finish
Small Thrust
The latest electric ducted fan products are examined by John Stennard
O
ver a period of time I have
built and flown quite a few
twin EDF models. Some
were built and flown as
originally intended while others were
brushless conversions of kit models or
RTF models. Some were also models
designed around brushless EDF systems.
Good examples of conversions are the
GWS A-10, the Skymaster and the Fokker
while the SML Learjet and E-flite Airliner
are models that were designed around 64
mm brushless fan units. The models varied
considerably in size but all flew well using
either a single shared LiPo feeding two
58
ESCs or two battery packs one for each
ESC and motor.
Recently I saw the J-Power twin engine
Eurofighter Typhoon advertised by Galaxy
Models and I reckoned that its twin motor
configuration would sound really good in
the air. On the website I liked what I saw,
especially as the Luftwaffe marking scheme
reminded me of my days in Deutschland!
Galaxy Models also had a J-Power version
of the A-4 Corsair so I ordered both models.
The twin engine Typhoon is fitted with a
3-cell EDF system while the A-4 Corsair is a
4-cell type.
Foam at its Best
When the Typhoon arrived I was
absolutely delighted with the quality of the
mouldings and finish. I chose the Luftwaffe
colour scheme and the paint job is excellent
and all the decal markings are already
applied. The EDF units, ESCs and the three
servos (two aileron and one for the nose
wheel steering) are in place. The Typhoon
has a 740 mm (29.125”) wingspan and a
length of 1068 mm (42”). The flying weight
is listed as 840 g (27 oz) and the suggested
battery pack is a 3S 2200 20C LiPo. I now
always spend a little more and buy LiPo
packs for use with EDF models of at least
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Small Thrust
The Skymaster conversion flew
extremely well and looked good in the air
ABOVE: The little Fokker was quite
fast and mildly aerobatic
BELOW: The brushless conversion of
the GWSA-10 was very successful
The E-flite airliner looked
extremely realistic
30C. I find that this improves the flying and
extends the pack life.
The EDF units had been test run and the
results recorded at 429 g, 14.5 A and 420 g,
14.5 A. If we estimate the combined units
at around 300 W using the 100 W per 500
g formula there should be ample power
for a model weighing around 840 g. The
EDF units are held in position when the
under fuselage hatch is screwed in place.
I decided to use a small amount of epoxy
to make sure they don’t move but can be
removed if required. The fuselage is a really
beautiful moulding with a particularly nice
air intake; in addition there are three large
cheater-holes on the underside. One small
concern was the fragility of the plastic nose
cone moulding. This could do with either
being made from thicker plastic or from
solid foam. As it is even light finger pressure
easily deforms it. The two ESCs and the
rudder servo are accessible via a hatch on
the top of the fuselage that uses magnetic
catches. Assembling the model is just a
case of gluing the wings, fin and canards in
place. I painted the aileron servos grey to
match the rest of the model.
The U/C mountings on the wings use the
locking clip method for securing the legs.
Because of the rather narrow track of the
main gear I added a screw to lock the clip
in place.
As usual I fitted a Spektrum Rx and
thought that the finished model looked
rather smart. I was pleased to see that the
cockpit had a crew inside.
A weight check with the supplied 3S LiPo
pack showed the weight to be almost spot
on and a motor run recorded a combined
current of 27 A and 312 W. I was really
looking forward to flying this model and
decided to do the first tests off a hard
surface.
Power Up And Go!
A little taxi around on the concrete resulted
in a couple of nose wheel adjustments so
that the model ran straight and the turning
circle was not too tight. If turned too tightly
the narrow width of the main U/C tends
to make the model tip over and the long
nose cowling can touch the ground. In a
minimal wind I opened up the throttle and
the Typhoon accelerated quickly but took
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The Learjet was possibly even
more realistic and flew very well
ABOVE: The
Kyosho Tornado
uses one motor
and twin ducting
but still flies well
LEFT: The
Typhoon box
art highlights
the attractive
appearance of this
model
ABOVE: The air intake is a very nicely
formed unit. Note the large cheater slots on
the underside
The different parts
are beautifully made
and finished to a very
high standard
The EDF units are actually loose and
designed to be held in place by the hatch
a surprisingly long run to come unstuck.
When it did come off the ground it climbed
at a steep angle until brought under control.
The flight characteristics were excellent
and the twin fan units sounded great and
gave plenty of power for steep climbs,
loops and rolls. Inverted flight was easy
and the Typhoon was extremely stable.
Landing the model proved problem free and
I was really pleased with the performance
and appearance of the model in the air.
Subsequent take-offs showed the same
characteristics and we came to the
conclusion that the three cheater holes were
creating an area of low pressure under the
fuselage. It needed speed and a sharp input
of elevator to lift the nose but once lifted the
Typhoon literally leapt off the ground. As full
60
power was not required for reasonably fast
cruising flight the LiPo pack gave a good
5-6 minutes of good flying.
The next tests were undertaken at our
grass flying field, again in a light wind.
Even though the grass was fairly short the
Tornado could not pick up enough speed to
take-off. As an experiment we tried blocking
off first one and then two cheater holes
but all this appeared to do was decrease
the thrust from the motors. Eventually the
model was hand launched, this is very easy
and it did not require a javelin type launch.
Even without the ability to ROG it’s still
preferable and satisfying to be able to land
the model on its U/C. Maybe with shorter
grass and more wind a ROG take-off
could be done but it does appear that for a
successful take-off there is a specific speed
requirement to ‘un-stick’ the model.
The Typhoon is a really super looking
model and the performance and sound of
those two motors is particularly satisfying.
Foam EDF models have come such a long
way and the better quality types are real
masterpieces of design and manufacture.
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