There were a few changes that I initiated on this ship which were. a departure
from the plans. These were not really necessary and nothing the average modeler
couldn't do himself. One was to incorporate the newest Du-Bro flaperon hardware
· to achieve the flaperons that are used on
the full scale Hiperbipe. Thfs change eliminates the bellcranlc: system and u~es torque
rods for aileron coutrol. The second was to
change the windshield pllttern outline.
The plans do not show the newest wiridshield patt.ern·, but if anyone would like it,
simply drop a line to me and I'll be more
than happy t? pass it along.
Many modelers may wish to use foam
core wings in place of the built-up construction. Being that the full scale ship had
fully sheeted wings, this will be fully acceptable but bear in mind that there will
be ll slight penalty to pay in weight. The
built-up construction used is light and very
' strong. One of my faults is to "overkill" on
construction, esp~ially the built-up type.
Foam cores will be mllde available to those
modelers who so desire them. The price is
$9.50 which includes postage. Order them
in care of Mllster Kit.
Remember, before you actually. start
building, it is easy to put on weight (especially the finish) but very hard to take it
off. Try to use as little epoxy as possible and
wipe all joints to remove excess glues. The
best weight for this ship is 5.25-5.5 lbs .
ByFrankM~:a-------~-------------·------~-------------------------------------------------y fascination with· the Hip~~·bipe
. began when I first spotted it on the
cover of Sport Flying Magazine,
Vol. 10, No. 1, Spring 1976. The cover of,
this magazine had a very attractive view of
this most unusual biplane performing
seemingly effortless knife-edge flight. It · ~~~~~~iili~lifp.~iiJ:;:~~~!!
was quite an impressive phbto and very
much characterized the hearty insatiable
aerobatic appetite of this out-of-the-ordinary negative stagger wing ship. As the
arti~le was carefully read and re-read, a
realization emerged that the magazine's
editorial staff was highly impressed with
N774HB and N18,RS showing detail of color deslgn_s. Taken at Bran·
this homebuilt. Nol only was the article
Field, Hartford, Connecticut.
comprehensive but complete with extensive photos .and three views.
From some angles the Hiperbipe is most
unpleasing and cou)d be considered . . .
"uug-a-lee." However, from others it is stubby" the more one has the feeling that Engines-.40-.45, (2) Weight-4 112unusual, and from a preferred few there the ship started out as an abandoned wing 5 l/2 lbs., (3) Construction- basic and
ca,n be no equal to its beauty. After one of which a slice was taken at the thickest straight forward for the average modeler,
looks at this short coupled, wide bodied, airfoiled section. As an afterthought, the (4) Wing alignments-consistent each
two wiuged wonder for any length of time, wings were added for stability. Actually, time the wings were bolted on, 5) As acmany of the seemingly unpleasant views this idea is not so farfetched, for the ori- curate an outline as possible would be
disappear. (This is·due to the phenomenon ginal design was that of an airfoiled fuse- maintained without sacrifice to structural
called angular selection.) It is then that'the lage that had the windshield extended to integrity, (6) Documentation and three
true functionality of the aircraft's design the spinner to achieve this airfoiled shape. views had to be easily obtainable, (7) AmDue _to engine heat and the hot sun on all ple radio space, (8) Wing loading of 18 oz.
becomes increasingly apparent.
The Sorrell family, who originated the that expanse of plexiglass the present sq./ft. at 4.5 lbs. ·
Hiperbipe, did extensive design research windshield shape was arrived ~t . All in all, . A prototype was built and many fine
along with trial and error building of the design is very successful and it was this points were learned about the aerodyseveral biplanes to arrive at the Riper's success that inspired me to immulate this namics of the negative stagger biplane
final configuration. The SNS6 (Sorrell very attractive ship in model form. Beauty configuration. The resuhant plans repreNegative Stagger 6th version) is the cul- is in the eye of the beholder and, to me, this sent the correct incidenCE)s, ·moments· and
minating result of all their hard work and ship is pure in aesthetics aud aerody- construction needed for exacting aerobatic
flight .
devotion to achieving one of the most namics.
Several models later I came across
I had been searching for a "sport scale"
classy, ae.robatic, daringly dlfferent designed homebuilts to date.
subject and wanted one that would be photos in Popular Mechan~cs , January '78,
From actual air show spectator com- unique yet allow conventional building of a , full-size Hiperbipe b';lilt by Ray
ments and written magazine coverage of tephniques at the same time. This ship cer- Stephen of California which had an unthe air show circuit, one would have to tainly fits that bill. Some basic design con- usual and most eye-catching paint scheme.
agree that Mark Sorrell (air show pilot of siderations foremost to me and these It almost bordered on being gaudy . . . I
SNS6) does such wondrous maneuvers were initiated in· the actual model con- loved it I Some of the photos reflect my atwith the Hiperbipe that the performance struction. As a first step, the parameters .tempt at duplicating this unusually
leaves the crowds awe-struck and in abso- were established and then the plans were painted Hiperbipe. As. a point of informalute amazement at the ship's aerobatic drawn as close to these as a built-up model tion, I found oul: that this was the first full
would allow. The following are the guide- scale Hiper.bipe completed from the SorT he more one looks at this "chubby- lines that the model centered around: (1) r~lls' kit offering to the E.A.A. home-
flying weight .
On to the construction.
Pre-cut all pieces to malce a semi-kit.
This fllcilitlltes construction and familiarizes one with all the parts.
The wings of a biplane are by nature
more of a chore to build by the very fact
that there are two of them. The bottom
wing being more difficult of the two
s~ould be built first. The wing is built in
three sections and then butt-joined.
Center Box- Pre-glue the four 3/16-in.
ribs. (2) Place the 3/16xl/4x7-in. spar on
the plans (cover the plans with wax paper
first) and place. the pre-glued ribs over
them. (3) Shim the back of the wide ribs
and the two center ribs so that they are
level, when satisfied glue them into position . (4) Clue the top front and top rear
spars to the ribs. Note that the rear spars
,are 1/ Bxl / 4-in. stock. (5) Clue the leading
and trailing edge into place. (6) Next the
webbing is glued into place. (7) Clue the
leading edge sheeting into place (l / 16x7)
after sanding the leading edge and trailing
edge to shape (box is still pinned to the
building board). (8) Add the rest of the top
bay sheeting. (9) Add the trailing edge at
this time. (10) Remove the hold-down pins
and proceed to sand the bottom leading
and trailing edges. (ll) Glue all the
1116-in. bottom wing SQeeting in place at
this time. (12) Dril13/ 16-in. holes for the
dowels and fit them into plllce but do not
glue at this time.
Left half-(1) Pin the 3/16xl/4-in. spar
to the plan sheet (bottom spar). Place the
ribs. and mark the locations. Cut the
1/8-in. rib to accommodate. the tongue of
the wing strut before gluing. (2) Pre-glue
the ribs where the interplane strut will slip
into. (3) Glue ribs into place except the rib
that will butt to the center box. This rib is
only tac-glued till assembly with the center
box. (Make sure the ribs are raised at the
trailing edge to be level.) (4) Glue the top
August 1978
front and top rear spars at this time. (5)
Glue the leading and trailing edges into
position; when dry, sand to shape. (6)
Glue the webbing into place except for the
innermost bay where the tac-glued rib is.
This webbing will be inserted after the
proper dihedral is set. (7) Cut the trailing
edge sheeting from the 1116x3x17 114-in.
stock and use the remainder for the leading
edge. When cut, glue into place. (8) Remove this half from the board and proceed
to sheet the bottom in the same manner as
the top. (9) Carefully pin the center section
level on the board. Establish the correct
height for dihedral · and remove the tacglued rib. With' a sanding block, carefully
sand till the spars of the left half meet the
center box's spars with the correct dihedral. (10) When satisfied with the
dihedral, liberally apply glue to the loose
rib and insert it in the wing, and at the
same time glue the left half to the center
box. (ll) Add capstrips. (12) Epoxy the
bellcrank mounting plate irito position,
noting that it is quite low in the bay. (13)
Add the webbing to this bay before final
. gluing of the bellcrank plate. (14) Glue the
wing tips on and carve to shape. Note the
shape from the plans. Be careful. Only
take off a small amount at a time till the
desired shape is established. You will note
that the curve is formed by a straight line
progressively going from a near vertical at
the leading edge to a near horizontal at the
trailing edge.
Right Half-Follow the same procedure
a~tpe left half. (2) Insert the 1 I 16 diameter
.. -cfuusic wire for the bellcranks. (3) Position
Servo installation showing aileron and flaperon with MRC servos and Du- Bro flaperon hardware .
., the bellcranks noting that the throw is cut
lone star aerobatic cap
down. When satisfied that all is working
free, glue the bay sheeting into position.
Ailerons-Fit the ailerons. There should
be 3/ 16-in. travel each way on the throw. does not move with the rudder.
Remove the ailerons till after glassing.
Glassing-Remove the 3/~6.-in. dowels
before glassing. It makes it much easier.
(1) Carefully build the fuselage frameUse no less than 4-oz. cloth and if the cloth
work over the plans. When dry build anweave becomes broken during sanding
other set on top of the first separating the
add another piece and feather it in. The
two halves with wax paper. (2) Add the
wings' center sections must be glassed at
bottom 114-in. wing saddle to each half.
the butt joints. Upon completion of the (3) Trace the cabin outline on a piece of
glassing, install the dowels and give them a paper and proceed to trace that outline on
coat of resin for fuel-proofing.
three 118-in. sheets. The cabin sheeting
covers the landing gear place and the sadTOP WING
dle blocks which are placed into position
upon the drying of the cabin sheeting
· The top wing is built in the same way as
(pre-glue the cabin sheeting). (4) Glue the
the bottom except that there is no sweep framework to the plywood pieces at this
and no dihedral. If you prefer, use the spar time. The two cross pieces at the tail are
full length without cutting it except for a
te the fuselage shape. Add all cross
Rearview of the frame. Note before and after landing gear fairing.
scarf joint which will come at the last bay planed
pieces. (7) Add the fuselage bottom sheetwhere there is little strength required. The
only exception to the building of the top ing at this time. (8) Fit the bottom wing - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - and upon the s&tisfaction of proper wing
wing will be the following: The thick ribs incidence," drill and tap holes for the hold- shown, or send for the ABS pants offered Aviation. See the references for their ad(built-up) are trimn:Jed slightly before the down bolts. (9) The bottom fairing can by Master Kit at $5.98 a pair. It is recom- dress .
gluing of the 1/8-in. plywood at the center now be glued to the bottom wing box. (10) mended they be glassed with 3/4-oz. cloth
Trim- The full size Hiperbipes to date
box, and before the sheeting goes on, the Add the landing gear plate and upon the (two layers) and K&B resin. Use Fox wheel have used Randolph Buterate Dope paints.
1 /8-in. plywood center brace must be cut installation of the gear,· cover the plate collars to fasten them to the-gear.
Sorrell's was Datona White and Montego
into the ribs behind the webbing. This
with 5/ 16-in. sheet. Do not sand this sheet
Green . Ray Stephen's was Pontiac red,
wing must also be gla~~ed. Please note that
till the cowl is made and fitted. (ll) Add
Creme Yellow, Ocala Orange, white and
the 118-in. ribs where the interplane struts
bakota Black. Top and side windows were
plug into should be notched on the bottom the 11 4-in. dash sheets (three pieces). (12)
with black Monocoat Trimcoat.
to accept the strut. Note: Pin all hinges
and, prior to installation, scuff them with top. (13) Install the horizontal stab and terial after shaping from 114-in. material. The decals that are availabl~ from Master
Cowl-'- The built-up balsa cowl can be Kit are for Sorrell's original paint scheme.
#80 paper. Use epoxy for gluing. Center vertical stab at this time. Check for proper
fairing is epoxied to the bottom wing's alignments. Recheck for proper align- fiberglassed with 4-oz. cloth and then the Flying wires can be simulated with elastic
center box upon completion of the ments. (14) Establish the proper incidence balsa hogged out. Use Goldberg brackets thread found in most fabric stores.
of the top wing and install bolts by drilling or a similar type for attachment. A fiberFlying- The Hiperbipe flies like no
and tapping the 11 4x20 bolt holes. If shim- glass cowl is available from Master Kit at other biplane in its category. It is fully
aerobatic, grooves beautifully and will do
ming is. necessary, Sig Epoxolite is a good . $12.95.
wayofdoingit.(15)AddF3atthistimefitCovering-The prototype was mono- any maneuver that you can concoct . . .
Pre-glue the pieces that make up the ting it to the indentation of the top wing's coated and weighed 4lbs. 3/4 oz. If other and then some. It is a pattern oriented type
stab. The use of epoxy is recommended center box. Glue 114-in. plywood braces coverings are used that require painting ship and landings may require a bit of power. This can be overcome by using the
here because it minimizes warping. Use it and dowels to F3 and add the windshield keep the primer coat light.
Flaperon hardware, torque rod
carefully being sure not to use too much.
Upon gluing, press flat till dry and wipe all the top wing and carefully fit the wind- .40 FSR and it had plenty of power. It was system, and keeping the model to the
seams and joints. Round off all eages and shield. Note the. small piece of material at. very dependable an~ possessed excellent weight limits mentioned earlier. Takeoff
requires a little right rudder. Elevator is
bring the elevator and HS4 to a point. The the top of the windshield at the top of F3. idle. A 10/6 propeller was used.
slightly up till takeoff speed is
elevator throw should be 3/8-in. each
Stuff or Eastman 910 to hold the acetate in found it to be responsive, very reliable, achieved, then neutralized. After the tail
place and then run a bead of epoxy around and it had the servo power I liked. We raises off the runway and the elevator
the windshield. Place pinholes all along would recommend it to all sport and scale neutralizes, a slight up elevator will proVERTICAL STABILIZER
.duce a beautiful lift-off. Do not "horse" it'
the edges of acetate to help adhere the contest oriented flyers.
Scale accessories such as the spinner and · off, for it will snap with insufficient airPre-glue the pieces and proceed to build epoxy.
wheels are standard store bought items . .. speed. It was designed for the most exactup the stab with the indicated lumber
The plans list them and we have found ing pattern and scale flyers. Once the ship
sizes. Round off the leading edges and sand
them to be as near scale as possible. Three . is flown and its unique characteristics exthe trailing edges to shape. The sub-fin
Shape the· pants from balsa and ply as views and photos can be had from Sorrell perienced, you won'dind its equal. Knife
August 1978
edge is a simple matter of rolling it on its
side and then maybe feeding a little bit of
rudder. Point rolls are absolutely beautiful
and crisp. It will track and groove as
though on a tightwire. Crosswind takeoffs
are no real problem if the tail is kept on the
ground as long as possible while awaiting
eluded in their kit. Write them for prices.
If you have any questions about the
building of the Hiperbipe, I would be
more than happy to answer them for you.
However, please be quite specific in
nature. Greatflyl Frank Massa, c/o Master
Kits-RCS, 6 Fox Rd., Plainville, CT 06062.
"It will track and
groove as though on a
tigh_t wire~"
"If you have any questions ... I would be ...
happy to answer them."
correct lift-off speed. The design is so unusual "that loops will thrill even the most
uninterested parties around.
Master Kit offers the kit to modelers
along with.the optional fiberglass cowl and
decals. ABS wheelpants and decals are in-
Three views of an ugly duckling. Ugly? Well ... "One man's ceiling is
another man's floor!"
Flying, Vol. 10, No. 1.
Spring 1976. Sport Aviation, March
1977. Sorrell Aviation, Rt. 1, Box 660,
Tenino, WA 98589. (Photo package
and large three views available.)
August 1978
By Patricia T . Groves
Hiperbipe: High PERformance BIPlanE.
Right now kind of rare. But getting less so
all the time.
A trio of the biplace, biwinged birds
gathered over the recent Memorial- Day
weekend . The reason? A form of summer
madness called "the fly-ln." This one was
at Watsonville along the shoreline of California's Monterey Bay.
From Tenino, Washington, Mark Sorrell flew down in the factory demonstrator, N774HB. And from Seattle, Ray
Wainscott piloted Dr. Wight Reade's
N775HB. When they arrived at the field,
they were met by Ray Stephen and his
polychromatic N18RS.
ABOVE: Swing low sweet chariot. BELOW: N18RS sits in line.
. Sorrell is 'delighted' about modelers building the H iperbipe."
" ... They perform as
pretty an air show as
you 're likely to -see."
Besides being a comfortable cross country airplane, the Sorrell Negative Stagger
biplane is an outstanding aerobatic aircraft. During daily demo flights, Sorrell
and the SNS-7 Hiperbipe displayed a partnership not often seen. Theirs is not a matter of man over machine, but an alliance of
two flyers. One, human. The other, not.
Together, they perform as pretty an air
show as you're likely to see. Though S~>rrell
credits the airplane: " It flies like it's on
rails. If you're going to do the knife edge,
you come in across the field, roll it 90 degrees, and if you've got the nose up when
you roll it, it'll climb. So you bottom rudder it down a little bit, and it just goes
st:eaini~g right along with no help from its
Most air show pilots use high power settings-rnnning 2700 rpms and 26-28
inches of manifold pressure. Mark does his
entire show at 2500 rpms and 25 inches.
Why? "I don't like to fly an airplane
br!ltally," he says. And you can tell. Together, their maneuvers flow gracefully,
one to the other.
Whether you're interested in building a
12-inch =- 1-foot Hiperbipe or a 2-inch =
1-foot \(ersion, you can obtain an information packet ($5.00) from Sorrell Aviation,
Rt. 1, Box 660, Tenino, WA 98589.
For history and technical background
on the airplane, see: Fall/ Winter 1966/67
• Copyright ~1.978 Patricia T. Groves
Homebuili Aircraft; February 1976 Aero•
plane Monthly; November 1971 Sport
Aotation; Spring 1976 Sport Flying;
March 1977 Sport Aviation; September
1977 Avtation News.
Like any manufacturer in the business
today, Sorrell is "delighted" about modelers bui[dingthe Hiperbipe. So, when you
finish yours, send him a photo.
Modelers will be particularly interested
in knowing that the paints on all three aircraft flown at Watsonville are standard
aircraft finishes m-anufactured by Randolph Products Company, P.O. Box 67,
Carlstadt, NJ 07072. Randolph is an old
line manufacturer of industrial and aircnift finishes, and local suppliers will have
August .1978
1''w o of three. visiting Hiperbipes prepare for a fly-by at ·
Wa.fs'on.ville. Tbe fuselage, tail group, engine/landing
gear m.o unt,. inferplane struts and flight control systems
are a'll welded 4\130 steel tube. Wings are ~I woodspruce spars• and_plywood ribs beneath a l/8-inch ply
slCin, fabric. covered.
Flaperons in aition, Ray Stephen comes in for a landing at
Watsonville (CA) over Memorial Day.
Nl8RS also spins a Hartzell prop, but spinner is );liper
Comanche. All three aircraft have 180 hp 10-360-BlE
Both N774HB andN775HB have Hartzell props and Hartzell spinners.
Fadorydem:oostrator here receives some TLC from Mark
SoJII'eU. Colott ~£ N774HB are overall Daytona White
trimmed in M'Oilitegii> Green. (See text.)
N175HB and N774HB have trim tab on rudder. None on
etevatar. No.te da~.pening weight on tail wires. (Also
pr~at· on N'Z'l4HB, but not on Nl8RS.)
Por~ side _
o f N774HB. Note word "Experimental" on flaperon. Not prese~t on N775HB. On all three aircraft, wings
have no filets; they butt right up against the fuselage:
LEFT: Panel of N77 4HB with Sorrell's wristwatch hanging from mixture control. Additional throttle (o.n the left) allows Sorrell to keep
his.right hand on the stick during aerobatics. CENTER: Panel of N775HB. About all that's really identical to N774HB is the position of
tile: nameplate! RIGHT: Instrumental panel of Nl8RS displays the Stephen's touch.
/ '
calor cllarts availabie.
Th<~ugb alike in mos{ ways, the three
a~rcraft visltiug; Watsonville are different.
N774HB: (Hiperbipe 12), the factory demonstr-ator, was' builtin 1975. The Stephen's
ab:craft, completed. in Aprill977, was the
U.liSt produced from the kit. Reade's
N715•H B can. be oo,nsidered, for· all practi'cal pw:poses. a. p10dluction aiq>lane be'in~
completed at tb.e. factory in November
. UJ'77.
sign, they w~nt through all .the agony and flight in your Hiperbipe then beeome8 as
frustration of getting the kits and campo- eagerly antiCipated as any family "birt~.':
nents approved under .FAR.Part 21, s~~
According to Sorrell, there are some 00_
tion_2Ll9l(g). So, when you buy -a kit, in Hiperbipes in various stages of construction. Most are · no doubt proceeding 'in
home garages here and there. So, if you've
:----~-:-::---~:-:-----::-~----~---::-------=~­ been wondering why your neighbor's car
·factory product (but you'll have to stand in . -essence you buy a license to manufacture has been standing outside recently, it could
line!). The only thing-the compBfly doesn~t one-:eaeh Hiperbipe. And-like -some-aero- be he's ~ hatchin' a Hiperbipe. Hmmm,
do is just sell the plans.
nautic adoptive parents, the Sorrells take wonder what kind of paint job he'S going
Because they had such faith in their de· you under wing. Your success ... your-first .to have~
In kit form, the Hiperbipe comes in all
stages of completion from ra~ pieces an4
parts 'to completed sections. Or, as in the
case of N775HB, Sorrell can build up a