SORRtrLt HIPtrRBIPE

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SORRtrLt HIPtrRBIPE
N?1AHB
AIRCRAFT DESCRIBED No. 233
SORRtrLt HIPtrRBIPE
Described by Ron Moulton, drawn by A. A. P. Lloyd
THE IDEA of utilising fuselagebulk as a lifting surface
is not new, nor is negativestagger,or full span flaplailerons, or composite construction. But throw this combination of less orthodox approaches together in a home
built designlike the Sorrell SNS-7 and the result is something that takes a while to get used to. We saw it perform
at the Abbotsford Air Show and it rates along with the
Colomban Cri-Cri and Rutan VariEzeas a showstopper.
Each of its featureshas purpose.The slab ofan aerofoil
fuselageis as wide as a car, so the seating is decidedly
more roomy than average.It is easily made, with tackwelded steel tube sides separated by constant length
crossbraces,and it feathersdown to the powerful elevator
which acts like a deflector. Tail surfacesare ogival delta,
curvy in outline and somewhatplain in the way they butt
to the fuselage.One might haveexpecteddeepfairings, but
Mark Sorrell assuredus they are not needed.The wings
follow the traditional 'swept and straight' pattern, only
upside down I The forward (lower) wing is the swept one,
and it fits snugly out of the way for easydoor accesswhile
the straight (top) wing has a transparentcentreto form the
large cabin roof. Unlike the rest of the airframe the wings
are wooden, with ply ribs wrapped by an $in. mahogany
ply skin. Symmetrical and th.in,they are clean as a whistle
and having the top surface extend over the lower allows
the fabric to form its own concavetip section.Flaperonsrun
from fuselageto tip on all panels.Each has a torque tube
leading edgeso that leverageis direct and all four control
surfaces can be drooped while still permitting aileron
action. It is this feature that makes the Hiperbipe an
aerobatictourer with docile landing speedsand short field
characteristics.Spring steel rod landing gear and sleek
spats couple with a very neat cowl to complete what has
already become a 'modeller's subject' for scale flying.
As an aerobatic mount, it has few peers.Mark showed
us vertical rolls, the famous Lomcevak, prolonged inverted
and loops with a snap roll at the top. For the tail slide
and stall turn it pours smoke to show a perfect pattem.
Its shapemakesit the talk of any show,and its performance
confounds any critic.
Hobie Sorrell designed the Hiperbipe (nrgh rnnformance srpnlane)in '73 when with sons John Mark, and
Tim, he formed Sorrell Aviation. That year the SNS-6
won the OutstandingNew Design award at Oshkosh and
Heading, the simple yet eff€ctiYe tip
curvature is achieved by having fabric find its own
ohape between ex.
tended
top, and
clipped lower ply
covering.
Wings
are very clean, as
also 3een at right
w i th
fl aper onr
downforslow land.
ing. There are no
external horns, a3
torque tubes are
c ontr ol l ed w i th
fuselage, Mass bal'
ances fair into tip
profile when neutral,
OF
R EPR IN T S
T H IS
F EAT U R E,
I l 24T t{
PLU S
SCALE DYE.LINE
AR E
PR IN T S
AS
AVAILABLE
PLAN PACK 2990,
PLU
S
PR IC E 35P
IOP PO ST AGE
FROM
AER OM O D ELLER
PLAN S SER VIC E,
P.O.
BOX
35,
BR ID GE ST R EET ,
H EM P.
H EM EL
ST EAD ,
H ER T S
H PI IEE.
The tooled leather seats and wall trim
together with the plush fabric lining and
cuperb mahogany veneered instrument
panel, combine to make the Hiperbipe a
very comfortable and roomy tourer more akin to the interior of a luxury
limousine, Flight shots of a stall-turn and
knife-edge pats rhow thG larSe untapered
fuselage and general rtral3ht-line rttllng,
far from resting on their laurels they set about improvementsfor the SNS-7.
Seldomhasa homebuilt prototypemadesuchan impact
in a scenewhere the radical or unorthodox approach is
the norm. One can so easily find home built aeroplanes
at the EAA fly-inswhich are bizarreto the point of being
jusl deliberately'different'.But the Hiperbipeis in a class
of its own. It rivals the Pitts for aerobatics.tours better
than a commercial 180 'spamcan',is more comfortable
than a quality car, and is better made than even those
glossy 'specials'. Only the steerabletail wheel is incongruous but that's an essontial for the excellent ground
handling.
All of which addsup to a DGA (Darned Good Airplane)
The port-side carries the door, which fits
so well it ir very hard to detect! Tubular
landing gear legs are cleverly faired over
whilc the use of a long spinner suits the
clean, smooth, cowling lines. Excellent
a l l - r o u n d vi i i b i l i ty i s a vailable, thanks to
the fact that the narrow chord lower wing
obrcurer only a small zone. All the glazinS
ir tinted black for anti.dazrl€ purpo3es.
in the American vernacular, which has already attracted
scalemodellersand kit manufacturers.
The originalcolour schemeof glosswhite with turquoise
blue trim and registrationis not the easiestto reproduce
in small scalepin striping, nor are the streamlinewires
simple for the purist but otherwise it's a perfect subject
for pointsscoringin scalecompetitions.
SPECIFICATION
Span:
Chortl;
Area;
Length OA;
Tailspan;
Propcller;
lllrceltrack;
Weight;
22ll lOin
3fi 3.9i n
150 sq.ft
20ft loin
9ft 5in
6ft 4in dia
/r r t tn
1236lbs
Cruise;
Max level speed;
stall(withflaps);
CeilirttE:
Take o./f run (SlL):
Landing run;
Rqnge;
150 mph
172 mph
49mph
20,000f1
4o0ft
595ft
502 miles
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