Top Flite RC-37 INSTRUCTION MANUAL
Biplane
RC-37 INSTRUCTION MANUAL
INTRODUCTION
The Elder Biplane is the third
design based on the popular
Elder-series of models. This
design is a direct result of popular
demand and it surely is the
largest model of the three. Your
Elder Biplane packs a huge wing
area of 1492 square inches, that's
10.3 square feet of lifting surface!
This means that when the model
is built within the expected
weight range of 7-1/2-8-1/2 pounds,
the resulting wing loading range
would be
square foot! It also means that if
you went with the heaviest engine
available and went crazy in the
detailing and finishing aspects of this model and managed to get the weight up to 10 pounds, the wing loading
would still only be 15.4 ounces per square foot!
All of the above allows your Elder Biplane to be powered
by a very wide range of engines. This design has been
tested quite successfully using 2-stroke engines as small
as .45 and on up to .75's. For 4-stroke work, we suggest
engine sizes of .60 to .90 in displacement. Like its smaller
counterparts, the real "kick" of this design is its extremely realistic flight characteristics. Slow fly-bys are breathtaking without the fear of losing aileron authority. Landings and take-offs are absolutely effortless. In the airyour
Elder Biplane is fully capable of some of the most realistic
aerobatics you've ever seen! You can expect beautiful
loops, stall turns and snap rolls, all at speeds that actual-
ly allow you to watch the airplane instead of a "blur".
Your Elder Biplane is a rugged design that will operate
11.6 - 13.1
ounces per
very nicely out of dirt, grass or paved flying fields. The unique, shock-absorbing landing gear, proto-typical of the
Elders era, really works to smooth out even the bumpiest
of fields. With its thick airfoil section and generous wing
area, your Elder Biplane will not tend to build-up excessive airspeed. This characteristic keeps the relative
inertia low and means that crash damage is kept to a
minimum.
Like otherEIders, the Elder Biplane lends itself to all kinds
of detailing, if you're so inclined. For the beginner,
nothing fancy is needed; just fly it and enjoy. For the
builder with an imagination, the Elder Biplane can be
detailed to such a degree that other pilots at your field will
swear the airplane is a scale model! In the COVERING &
FINISHING section of these instructions there are some
ideas for detailing that might be of interest, please take
the time to read them.
TOP FLITE MODELS INC.
2635 S. WABASH AVENUE • CHICAGO, ILLINOIS 60616
Earlier we touched on engine recommendations. Your
Elder Biplane kit contains a high-quality filled nylon motor
mount that will work with some of the engine suggestions
or this design, but not all. If the engine choice for your
Elder Biplane will not work with this mount, it might be
necessary to visit your local retail hobby shop to obtain
the correct motor mount for your engine.
IMPORTANT NOTE:
TOP FLITE MODELS, INC. Would certainly recommend
the Elder Biplane as a first R/C powered aircraft.
However, if you are a beginner to the sport of R/C flying,
we would urge you to seek and use experienced
assistance in constructing and flying this airplane.
Again, if you are new to this hobby, consider this:
Flying this or any other radio-controlled model aircraft
a
PRIVILEGE and not a RIGHT and this privilege begins
with the utmost safety considerations to others and
yourself as well. An R/C model airplane in inexperienced
hands has the potential of doing serious personal or property damage. These safety considerations start at the
building board by following instructions, seeking com-
petent help when you are confused and avoiding shortcuts. These considerations have to be carried overto the
flying field where safety must come first and limitations
cannot be exceeded. We urge you to:
1.Send for and obtain your AMA (Academy of Model
Aeronautics) membership which will provide insurance for your R/C activities — DO NOT RELY
HOMEOWNERS INSURANCE.
ON
2. Join an AMA sanctioned R/C flying club in your area
where you can obtain competent, professional instruction in trimming and learning how to fly this
model.
Check with your favorite local hobby shop for the required AMA forms or the address where they can be obtained.
WARNING!!!
A radio controlled model is not a "toy." Care and
caution must be taken in properly building the
model, as well as in the installation and use of the
radio control device. It is important to follow all
directions as to the construction of this kit as well
as installation and use of the engine and radio
gear. The advice and assistance of a well ex-
perienced builder and pilot is highly recommended. Don't take chances! Improper building, operation, or flying of this model could result in serious
bodily injury to others, yourself, or property
damage.
PRE-CONSTRUCTION NOTES
The Elder Biplane, like other Top Flite kits employs the
use of die-cut wood to ease the task of construction,
parts fit and identification. The dies used for this kit
have been rigorously checked for absolute accuracy
and should provide you with excellent fit. Die-cut parts
should be carefully removed from their sheets by first
lightly sanding the back of each sheet of parts and then
carefully removing each part. Use a light garnet paper
for the sanding and keep a sharp hobby knife with an
X-acto #11 blade, or equivalent, handy for assistance in
removing any parts that might not have completely cutthrough by the dies. Parts which oppose one another
and must be precisely uniform—such as fuselage sides,
ribs, etc.—should be carefully "matched" after their
removal from the part sheets. Matching is the process of
holding the opposing pieces together with either pins,
tape or spot gluing and lightly sanding the edges of the
parts until they are identical. A sanding block with light
garnet paper is most useful for this and other phases of
construction.
is
Your building surface should be at least large enough to
accommodate the wing panels. This surface should be
as absolutely flat as possible and yet be able to accept
pins easily. We have found that a product such as
Celotex fiber board works quite well for this purpose.
Anothergood surface can be found in most well-stocked
hardware stores-a 2'x4'fiberboard ceiling tile. These
are quite inexpensive and can be used for several
airplanes before needing replacement.
As with most R/C kits that are constructed from wood, a
selection of tools - most of which can be found in the
average workshop - are a must to do the job correctly:
• Hobby knife and sharp #11 blades
• Single-edge razor blades
•T-pins
• Sanding blocks in assorted sizes
• Sandpaper in various grits
• Hand-held hobby saw, such as an X-acto
• Dremel tool or power drill and assorted drill bits
• Straight-edge, preferably metal, at least 36" long
• 90" triangle
• Soldering iron, flux (silver) and solder
• Carbide cut-off wheel for wire cutting
• Small power jig-saw, such as a Moto-Saw
• Razor plane
• Tapes, such as masking and cellophane
Our Elders were constructed using a variety of
common hobby adhesives including 5-minute epoxy,
cyano-acrylates, and 1-hour epoxy. Since all of us have
our own construction techniques and favorite
adhesives, stick with the ones you are familiar with and
prefer. However, in certain areas there will be callouts for
certain types of adhesives, and we urge you to try not to
substitute since doing so could possibly cause
problems structurally.
The last thing we should touch on before we begin
actual construction is the sequence in which the Elder is
assembled. The sequence given to you in this booklet
has proven to be the most straight-forward and provides
the finished components in the order in which you will
need them to progress to the next assembly phase. Try
to stick with the building order presented here to avoid
mistakes.
2
Spread the plans out on your work surface, cover them
with a clear plastic material, such as the backing from
a roll of MonoKote® or plastic wrap and commence
construction.
UPPER WING ASSEMBLY
Wing construction for your Elder Biplane consists of
building three separate pieces for each wing; the two
panels and the center section. Note that the upperwing
panels will be joined to the upper center section in the
following sequence, without the top, inboard ends
sheeted. This sheeting will be done in the FINAL
ASSEMBLY section of the manual. In this and other
building sequences, be certain that you are working on a
flat work surface. Carefully join the plans for the TOP
LEFT WING and the TOP RIGHT WING, Plan Sheets 5
and 6, at the center line provided and accurately secure
with tape. This provides the full wing plan on which to
work. The wing will be built directly over the plans, so
cover them with MonoKote backing or clear food wrap.
1. Start with the center section first. Locate the die-cut
sheets containing parts W-11 (2, ply), W-12 (2, ply).
W-13 (1, balsa), 4W-1 A's and 4 W-1 B's. Remove these
parts from their sheets and clean up any rough
edges before assembly
2. Using the plans as a guide; measure, cut and butt-
glue
the 1/4" x 1-1/2" lower leading edge, 3/32" balsa
sheet and the 3/32" x 1" trailing edge that makes up
the bottom of the center section. Note grain
direction of these pieces. Measure, cut and glue in
place the 3/8" x 1/2" upper leading edge. Glue one of
the W-11 ply dihedral braces in place against the
inside surface of the leading edge—be sure that it's
centered. Glue the outer W-1A half-ribs in place
against the rear face of the dihedral brace, lined-up
with the edges of the bottom sheeting at right angles
to your work surface. Now glue the two remaining
W-1A's in place, using the "tick" mark locations on
the plan.
3. As shown, the main dihedral brace system is a
composite made by laminating the two W-12's (ply)
to each side of W-13, which results in a 1/4" thick
part—do this now. Glue the completed dihedral
brace in place to the bottom sheeting and up against
the rear edges of the fourW-IA's. Be sure this part is
centered.
4. From your kit box, locate a piece of 1/4" x 1/2" spar
stock and cut two 5" lengths. Glue one of these
pieces in the top rear slots in the W-1 A's and against
the top forward face of the center dihedral brace.
Glue the other on the bottom sheeting against the
bottom rear face of the dihedral brace.
5. Now glue the fourW-1B rear half-ribs in place behind
the main dihedral brace. Glue the remaining W-11
(ply) dihedral brace in place on the bottom sheeting
and against the rear edges of the four W-1 B's. Locate
the 1/4" x 3/8" trailing edge material in your kit box
and cut a 5" length. This is now glued in place
against the rear face of the rear W-11 brace and to
the bottom sheeting.
TOP WING CENTER SECTION
CAP STRIPS AND
3/32" x 1" TRAILING
EDGE NOT SHOWN
3
6. Internally, the center section is done and all that
remains is the addition of the top 33/32"
sheeting—note grain. From the sheeting stock
provided, cut, fit and glue the sheeting in place.
When dry, remove the center section from your work
surface. Useyoursanding block tosmooth it'souter
W-1A and W-1B sides for mating to the outer wing
panels. The top, bottom and leading edge can now
also be sanded to shape. Set this assembly aside
now.
7. In this step we want to prepare each of the required
components—the top and bottom spars, the 3/8" x
1/2" front L.E. and the rear 1/4" x 3/8" T.E.—with the
proper dihedral angle at their inboard ends. The
cross-section of the wing that is shown on the plans
is ideal forthis purpose. Simply lay, for instance, the
bottom 1/4" x 1/2" balsa spar in place over this
drawing. Note that the outboard end is cut at 90
degs.; but that the inboard end must be cut at an
angle to achieve the required 3/4" per panel dihedral
angle. Make two of these bottom spars. Now repeat
this process with the top spars, the leading edges
and the trailing edges (note that the length of the
leading edges is developed from the top view of the
wing plan). The inboard edges of the
lower leading edges should be first cut at 90 degs.
and then slightly chamfered to match the needed
dihedral angle.
8. Start construction by first
lower leading edges in place, directly overthe plans.
Note that the inboard edges of these two parts
terminate at the out edges of the two outboard
W-1A's. Now pin the 3/32" x 1" bottom trailing edge
planking in place. Glue the 1/4" x 3/8" trailing edges
in place on the top, rear of the 3/32" trailing edge
bottom sheet. From your kit box locate two 28"
lengths of the tapered
on the plans that the inboard ends of the tapered
trailing edges have been scalloped to blend into the
center sections, using the plans as a guide, do this
now. Glue the tapered trailing edges in place—pin
securely. From the 3/32" x 1/4" x 36" stock provided,
cut, fit and glue each of the bottom capstrips in
place—pin to secure. Using the 3/32" sheet balsa
provided, measure, cut and glue the inboard bottom
wing sheeting in place—note grain direction.
Locate the two required W-6 wingtips, clean their
edges and glue in place. The bottom 1/4" x 1/2" spars
(angled ends inboard) are now glued in place to the
bottom wing sheet and capstrips. Now glue all
required W-2A, W-2B, W-3 and W-4 ribs in place,
making sure they are vertical to the work
surface—DO NOT glue W-3P's in place yet.
9. From your kit box locate the die-cut sheet
containing the four "light ply" W-3P wing ribs. Both
the upper and lower wings use two of these special
ribs for attachment of the interplane struts. Note
that each of these ribs have indentions on them for
location and placement of the nylon mini horns,
used for attachment of the interplane struts. On the
1-1/2"wide
pinning
the
trailing stock. Note
balsa
for
1/4" x 1-1/2"
1/4" x 1-1/2"
upper wing, the location of these horns is shown on
the lower left side of plan sheet #5. Route or cut a
slot between the two lower sets of front and rear
indentions to allow the base of the mini horn to fit.
As long as you're doing this now, go ahead and cut
the slots required for these ribs for the bottom
wing—these are the top front and rear set of
indentions. Once the ribs have been properly
slotted, place the two required for the bottom wing
back in your kit box for later assembly. The two
appropriate W-3P ribs for the top wing are ready for
installation. First, cut, fit and glue in place the 3/32" x
1/4" lengths of capstrip stock shown on the plans as
fitting directly beneath each of the mini
locations. Glue W-3P's in place.
10. Locate and remove 14 W-5 rear angled ribs from their
die-cut sheets. Note on the plans that the forward
ends of these ribs are chamfered to fit against the
W-3 rib sheets and that their placement does not
interfere with the placement of the top spar slots.
Also note that the innermost W-5 rib must be
trimmed slightly so as not to interfere with the
placement of the main dihedral brace. GlueW-5's in
place. Glue all of the wingtip braces (W-7, W-8, W-9,
W-10, and W-15) in place on the W-6 wingtips. Note
that W-7, W-9 and W-10 need to have their inboard
ends chamfered with a sanding block to fit flush to
the outer face of W-3.
11.
From your hardwood parts bag, locate the four 1/2" x
5/8"" x 1-1/2"
epoxied in place as shown on the plans, against the
inboard faces of W-2A and W-2B and to the bottom
3/32" bottom center wing sheeting—we suggest
use of a 1-3 hour-type epoxy for this step.
12. Now take the center section which was assembled
earlier and fit it to one of the wing panels. Tilt it until
the two arms of the W-11 ply dihedral braces fit flush
to the front and rear bottom sheeting and the center
brace assembly is correctly positioned against
the bottom spar. Check this fit to be sure all
components fit nicely. Trim as needed to get proper
fit. Prop and/or pin this center section in this
position as you will use it as a guide for the
remaining wing panel parts. Remember not to glue
anything to the center section yet; it's only in place
for spacing purposes.
13. Glue the front 3/8" x 1/2" leading edge in place on top
of the lower
front of each full and half rib (angled end inboard to
fit against tilted center section). Glue the top 1/4" x
1/2" spar in place (angled end inboard). Cut, fit and
glue the 3/32" x V leading and trailing edge planking
in place—pin or tape to hold. Remove the center
section from the wing panel and repeat the above
steps on the remaining panel.
14. Cut, fit and glue all top 3/32" x 1/4" capstrips in place
on all of the ribs and half ribs.
15 Remove the wing panels from the work surface.
Inspect them for any dried globs of glue, remove
cabane support blocks. These are now
1/4" x 1-1/2"
leading edge and against the
horn
the
4
these with a #11 X-acto knife. Tape or hold the two 2.
wing panels together with the bottoms of each
facing the other—align carefully. Use your sanding
block to now shape the forward wingtips identically
with each other and the curves shown on the plans.
With the exception of the inboard ends, use your
sanding block to carefully 'match' the wing panels,
leading edges, tips and trailing edges. Separate the
panels and use a sand ing block with light paper over
all of the panel's surfaces to smooth them for later
covering.
16. Firmly pin and/or weight the center section over your
protected work surface and epoxy the left and right
wing panels in place to it, with the tips of each panel
supported off the work surface by 3/4" to impart the
correct dihedral. Do not use so much adhesive that it
drips or runs but enough to adequately coat the
parts required. Using a 1-3 hour type epoxy will give
you plenty of time to position all of the components. 3.
Allow the structure to cure.
Remove the wing from your work surface and
inspect your work. Do any touch-up sanding or filling
as needed. The upper wing is now complete with the
exception of the upper panel sheeting over the
hardwood blocks.
Using the plans as a guide; measure, cut and buttglue the
sheet and the 3/32" x 1" trailing edge that make up
the bottom of the center section. Note grain direction of these pieces. Measure, cut and glue in place
the 3/8" x 1/2" upper leading edge. Glue one of the
W-11 ply dihedral braces in place against the inside
surface of the leading edge—be sure that it's
centered. Glue the two outer W-1A's in place against
the rear face of the dihedral brace, lined-up with the
edges of the bottom sheeting at right angles to your
work surface. Now glue two W-1A's in place just in-
board of the outer ones—note "tick" marks on
plans. The two remaining W-1A's are now glued in
place, at the center of the structure, spaced 1/4"
apart to allow later dowel insertion.
As shown, the main dihedral brace system is a composite made by laminating the two W-12's (ply) to
each side of the W-13, which results in a 1/4" thick
part—do this now. Glue the completed composite
dihedral brace in place to the bottom sheeting and
up against the rear edges of the six W-1A's. Be sure
this part is centered.
1/4" x 1-1/2"
lower leading edge,
3/32"
balsa
LOWER WING ASSEMBLY
The lower wing for the Elder Biplane is almost identical in
constuction to that of the upper wing, just built. Part
numbers and wood sizes are also the same. However,
there are some differences, primarily in the center section structure and in part counts. Carefully join the plans
for the BOTTOM LEFT WING and the BOTTOM RIGHT
WING, Plan Sheets 3 and 4, at the center lines provided
and accurately secure with tape. This provides the full
wing plan on which to work. The lower wing, like the top,
will be built directly over the plans, so cover them with a
MonoKote backing or clear food wrap.
1. Start with the center section first. Locate the die-cut
sheets containing parts W-11 (2, ply), W-12 (2, ply),
W-13(1, balsa), 6W-1A's and 4W-1B's. Remove these
parts from their sheets and clean up any rough
edges
before assembly.
4. From your kit box, locate a piece of 1/4" x 1/2" spar
stock and cut two 5" lengths. Glue one of these
pieces in the top rear slots in the W-1A's and against
the top forward face of the center dihedral brace.
Glue the other on the bottom sheeting against
bottom rear face of the dihedral brace.
5. Now glue the four W-1B rear half-ribs in place behind
the main dihedral brace. Glue the remaining W-11
(ply) dihedral brace in place on the bottom sheeting
and against the rear edges of the four W-1B's. Locate
the 1/4" x 3/8" trailing edge material in your kit box
and cut a 5" length. This is now glued in place
against the rear face of the rear W-11 brace and
the bottom sheeting.
the
to
5
BOTTOM WING CENTER SECTION
6. In this step you are going to assemble the 5" length
of shaped hardwood trailing edge stock and the
aileron torque tubes and wires to the wing center
section. Also locate and remove from their die-cut
sheets, parts W-14 and W-14B (due to the die-cut process, you have been provided with two sets of these
parts, you will need only one set). Please refer to the
detail drawing provided to understand the relationship of these parts.
Start by glueing W-14A to the front face of the
tapered hardwood trailing edge piece. Make sure
W-14A is centered and that the bottom edge of the
part coincides with the bottom surf ace of the trail ing
edge piece. As shown, the trailing edge must be
notched a little to allow rear movement of the threaded linkage arms. Do this now with either a rat-tail file
or a Moto-Tool and router bit. Note that there is a
right and a left aileron drive assembly. Hold one of
these assemblies (it makes no difference which one)
in place to the trailing edge/W-14A assembly in it's
proper location. Apply glue to the rear face only of
one of the tapered W-14B's (tapered end outboard)
and glue it in position to the front face of the trailing
edge, thus providing a "nest" for the aileron drive
assembly. Repeat this process for the opposite side.
Remove the aileron drive assemblies and use a
sanding block to true-up each side of the trailing
edge assembly (top and bottom) and each end. Insert the two aileron drive assemblies into their appropriate "nests" and hold this entire assembly to
the trailing edge of the wing center section. Note
that you now must slightly notch the center
section's 1/4" x 3/8" trailing edge to allow forward
movement of the threaded linkage arms—do this
now. Remove the two aileron drive asemblies and
usesandpapertorough-upthesurfaceofeachofthe
assemblies' brass tubes. Mix a small amount of 1-3
hour epoxy and carefully glue only the torque rod
6
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