Old School Model Works Lark Instructions for use

CONSTRUCTION
MANUAL
www.oldschoolmodels.com
Using the Manual
Be sure to read each step thoroughly before you start
the step. Test-fit the parts together to make sure they
fit properly. If necessary trim to fit.
Beside each step you will notice a check box (or two).
These are so you can keep track of your progress
while building your kit. For steps that have two boxes,
as in the construction of the left and right wing halves,
these steps must be performed two times.
• Your Old School Model Works aircraft should not be
considered a toy, but rather a sophisticated, working
model that functions very much like a full-size airplane.
Because of its performance capabilities, this model, if not
assembled and operated correctly, could possibly cause
injury to yourself or spectators, and damage to property.
• You must assemble this model according to the
instructions. Do not alter or modify this model, as doing
so may result in an unsafe or un-flyable model. In a few
cases the instructions may differ slightly from the photos.
In those instances the written instructions should be
considered as correct.
• You must take time to build straight, true and strong.
• You must use a R/C radio system that is in first-
class condition, a correctly sized power system and
components (electronics, batteries, wheels, etc.)
throughout the building process.
• You must correctly install all R/C and other components
so that the model operates correctly on the ground
and in the air. (Installation shown in the manual is a
suggestion. You may have to adjust the mounting steps
to accommodate the size of your radio equipment.)
• You must check the operation of the model before every
flight to insure that all equipment is operating and that
the model has remained structurally sound. Be sure to
check clevises or other connectors often and replace
them if they show any signs of wear or fatigue.
• If you are not an experienced pilot or have not flown this
type of model before, we recommend that you get the
assistance of an experienced pilot in your R/C club for
your first flights. If you’re not a member of a club, your
local hobby shop has information about clubs in your
area whose membership includes experienced pilots.
• While this kit has been flight tested to exceed normal
use, if this model will be used for extremely high stress
flying, such as racing, or if a power system larger than
one in the recommended range is used, the modeler is
responsible for taking steps to reinforce the high stress
points and/or substituting hardware more suitable for the
increased stress.
Remember: Take your time and follow
the instructions to end up with a well-
built model that is straight and true.
Specifications:
Wingspan: 56 in.
Wing Area: 560 sq in.
Airframe Length: 42.5 in.
Weight: 3.75 - 4.5 lb.

Page 2 www.oldschoolmodels.com Construction Manual
WARNING
READ THROUGH THIS MANUAL
BEFORE STARTING CONSTRUCTION.
IT CONTAINS IMPORTANT WARNINGS
AND INSTRUCTIONS CONCERNING
THE CONSTRUCTION AND USE OF THIS
MODEL.
A Radio-Controlled aircraft is not a toy!
If misused, it can cause serious bodily harm
and damage to property. Fly only in open
areas, preferably at AMA (Academy of Model
Aeronautics) approved flying sites, following all
instructions included with your radio, powerplant,
electronics and batteries.
• Inspect your model before every flight to ensure it is airworthy.
• Be aware of any other radio frequency user who may present an
interference problem.
• Always be courteous and respectful of other users in your
selected flight area.
• Choose an area clear of obstacles and large enough to safely
accommodate your flying activity.
• Make sure this area is clear of friends and spectators prior to
launching your aircraft.
• Be aware of other activities in the vicinity of your flight path that
could cause potential conflict.
• Carefully plan your flight path prior to launch.
• Abide by any and all established AMA National Model Aircraft
Safety Codes.
IMPORTANT!!! Two of the most important things you can
do to preserve the radio controlled aircraft hobby are to avoid flying
near full-scale aircraft and avoid flying near or over groups of people.
INCLUDED ITEMS
Wood parts included in this kit:
• 1 - LP1 - laser cut 1/8” x 5" x 24" ply
• 1 - LP2 - laser cut 1/8” x 5" x 24" ply
• 1 - LP3 - laser cut 1/8” x 2" x 24" ply
• 1 - LP4 - laser cut 1/8” x 5" x 24" ply
• 1 - LP5 - laser cut 1/8” x 5" x 24" ply
• 1 - LP6 - laser cut 1/8” x 2" x 24" ply
• 1 - LP7 - laser cut 1/16” x 5-3/4" x 3" ply
• 2 - BP1 - laser cut 1/8” x 4" x 24" balsa
• 1 - BP2 - laser cut 1/8” x 1" x 24" balsa
• 2 - BP3 - laser cut 3/32” x 4" x 24" balsa
• 2 - BP4 - laser cut 3/32” x 4" x 24" balsa
• 1 - BP5 - laser cut 3/32” x 4" x 24" balsa
• 2 - BP6 - laser cut 3/32” x 4" x 24" balsa
• 2 - BP7 - laser cut 3/32” x 4" x 24" balsa
• 2 - BP8 - laser cut 3/32” x 4" x 24" balsa
• 1 - BP9 - laser cut 3/32” x 4" x 24" balsa
• 1 - BP10 - laser cut 3/32” x 4" x 12" balsa
• 1 - BP11P - laser cut 1/8” x 4" x 12" balsa
• 1 - BP11S - laser cut 1/8” x 4" x 12" balsa
• 1 - BP12P - laser cut 1/8” x 4" x 12" balsa
• 1 - BP12S - laser cut 1/8” x 4" x 12" balsa
• 1 - BP13 - laser cut 1/8” x 4" x 12" balsa
• 2 - BP14 - laser cut 1/16” x 4" x 24" balsa
• 2 - BP15 - laser cut 1/16” x 4" x 24" balsa
• 1 - BP16 - laser cut 1/16” x 4" x 24" balsa
• 2 - BP17 - laser cut 1/16” x 4" x 12" balsa
• 2 - BP18 - laser cut 1/16” x 4" x 12" balsa
• 1 - 1/16” x 4" x 12" balsa sheet
• 2 - 1/2” x 1/2” x 36” balsa strips
• 2 - 1/4” x 1/2” x 36” balsa strips
• 2 - 1/4” x 1/4” x 36” balsa strips
• 4 - 3/16” x 3/16” x 36” balsa strips
• 4 - 1/8” x 1/8” x 36” basswood strips
• 4 - 1/4” x 1/4” x 36” basswood strips
• 2 - 5/16” x 1-1/4” x 36” tapered balsa strips
• 1 - 1/4”x 6” wooden dowel
• 1 - 3/16”x 6” wooden dowel
Hardware parts included in this kit:
• 8 - magnets
• 2 - pre-bent main gear wires
• 1 - nose gear assembly
• C/A type hinges for control surfaces
• 4 - control horns
• 2 - wheel collars 5/32” I.D.
• 4 - plastic gear straps
• 8 - 2-56 x 1/2” machine screws
• 20 - 2-56 x 3/4” self tapping screws
Other items included in this kit:
• 2 - Rolled plans (fuselage and wing)
• 1 - Construction Manual
• 1 - Formed Canopy
ITEMS NEEDED
Hardware needed (not included in the kit)
For some of these items there is more than one option which will
require a bit of decision making ahead of time. There isn’t a right or
a wrong choice, so choose the items that work best for you.
We strongly recommended supporting your local hobby shop.
• Powerplant: .25-.40 sized 2-stroke glow engine (or similar
electric system)
• Propeller
• Engine/Motor mount and mounting hardware
• 4-6 ounce fuel tank and fuel tubing (if glow)
• Receiver - (4 channel minimum)
• 4 servos (electric) or 5 servos (if glow) - we recommend standard
servos all around, although you can use a smaller servo on the
throttle, if using glow power).
• “Y” servo harness (for ailerons)
WARNING: This product can expose you to chemicals including lead, which
is known to the State of California to cause cancer and birth defects or other
reproductive harm. For more information go to www.P65Warnings.ca.gov.

Construction Manual www.oldschoolmodels.com Page 3
• Pushrods (two 5” for ailerons, two 26” for elevator & rudder,
one 14” for nose gear steering, one 10” for throttle if glow.)
• Clevises for the pushrods.
• Wheels: one 2-1/4" for nose, two 2-1/2” for mains.
Sure there are a lot of wheels out there, but let's face facts.
It's DuBro Chromies for the win here - it's just the right look.
• Covering (2 rolls typically)
• Optional 2-1/4" or 2-1/2" spinner
Additional Required Building Tools and Adhesives
• Drill & assorted drill bits
• Hobby knife and #10 blades
• Sandpaper: coarse (80 or 100 grit) & medium (150-200 grit)
• Pencil or pen
• Ruler
• T-Pins
• Waxed paper
• Building board
• 2-part epoxy (6 or 15 minute)
• Epoxy brushes and mixing sticks
• Wood adhesives of your choice. We use medium viscosity CA
(cyanoacrylate) , but aliphatic resin and/or carpenter’s glues (used
correctly) will work just as well and give longer working time.
• Thin CA for attaching the included hinges
Although an easy to build kit, our Lark kit is not for the novice
builder. We are assuming the builder is used to constructing balsa
kits and has the techniques and skills necessary to do so.
Closely inspect the supplied laser cut parts for damage. If you find
any damaged or missing parts, contact us immediately.
When removing the laser cut parts from their sheets, you’ll notice
the parts are held in place by several small “tabs”. These tabs
are uncut pieces of wood and can sometimes make it difficult to
remove a part. Rather than breaking and/or splintering the wood
by forcing out the part, we recommend removing any laser cut
parts from their sheets by using a hobby knife with a #10 blade.
A quick cut of the tab will allow the piece to be removed with no
damage. Sand any tab remainders flush with the part so there will
be no problem aligning them later.
It’s best to not remove parts from their sheets until they are needed.
Refer to Appendix A of this manual as a reference to what all the
laser cut parts look like and are called.
You’ll notice a check box next to each step. Check these off as
you go along so you don’t miss a step. Note that some steps (in
building the wing) have two boxes - this means that the step will be
done twice - once for each wing half.
There could be a step or two which leaves you a bit puzzled. If this
happens, step back and study the photo(s) for that step - both in
this manual and online.
All photos shown in this manual are of different Lark prototypes.
Several pieces may have changed slightly with improvements
we’ve made so parts may look a little different in some steps.
Online Supplementary Photos
We realize that the smaller black-and-white photos in this manual
might not show some of the steps as
clearly as you might want. So we’ve
anticipated this and made these photos
available on our website. You can either
scan the QR code or type this address
into your browser:
www.oldschoolmodels.com/mpics/lark/
IT IS VERY IMPORTANT THAT YOU ASSEMBLE THE LARK
KIT IN THE ORDER DESCRIBED. SKIPPING FORWARD IN
THE STEPS COULD LEAVE YOU WITHOUT THE PROPER
LENGTHS OF WOOD TO FINISH THE KIT.
WE’VE INCLUDED ENOUGH WOOD TO EASILY COMPLETE
THIS KIT, BUT YOU MUST TAKE CARE TO PROPERLY
MEASURE AND NOT WASTE WOOD WHEN CUTTING.
Let’s begin construction by working on the starboard (right)
wing of your Lark.
n Prepare your work area
You’ll need a flat building surface
that is a minimum of 36” long.
Position the starboard wing
plan over the surface and tape
into position. Tear off a length
of waxed paper long enough to
cover the port wing plan and tape that into position, over the plan.
n Alignment triangles
Pre-cut into LP1 is a 90° triangle. This can be
used to vertically align any of the parts in the
construction of your Lark. LP1 also includes a
foot piece that can be used with the triangle to
hold it vertically (hands-free).
n n Step 1 - Wing Assembly (front spar)
These next few step will create the front spar. It is recommended
that you use a long, straight edge during these steps to ensure that
the finished spar is straight and true.
Locate one of the 1/4” square
x 36” lengths of basswood,
and one SP2 from BP1. Glue
the longer edge of SP2 to
the basswood as shown here,
with them lined up at one end.
Make sure that SP2 is pressed
up against the basswood along it’s entire length, and is also held
flat against your building board as shown in this photo.
n n Step 2 - Wing Assembly (front spar)
Locate one SP1 from BP1. This is glued in place to SP2 and the
basswood by lining up the modified scarf joint pre-cut into the
pieces. Again, make sure this is
aligned straight with the straight
edge, and flat along the entire
length where it contacts the
basswood strip.

Page 4 www.oldschoolmodels.com Construction Manual
n n Step 3 - Wing Assembly (front spar)
Locate another SP2 from BP1
and this is now glued on top of
the SP1 you just installed. This
will allow the lower and upper
scarf joints to overlap, rather
than be aligned. Again, make
sure that this SP2 is glued to
the SP1 (and the overlapping portion of SP2) below it, as well as
where it contacts the basswood strip. Make sure this joint is straight
as shown here.
n n Step 4 - Wing Assembly (front spar)
Now locate another SP1 and glue
in place, aligning the laser-cut scarf
joints and making sure it is properly
positioned as the glue cures.
n n Step 5 - Wing Assembly (front spar)
To complete this spar, locate another
of the 1/4” square basswood strips.
Glue this to the edge of the spar
assembly, to the edges of the SP1
and SP2 pieces as shown here. Make
sure it’s flat and straight along it’s
entire length.
n n Step 6 - Wing Assembly (front spar)
Once the glue has cured in the spar assembly, remove it from the
building board and lightly sand it’s surfaces to make sure they are
flat and smooth, removing any glue bumps that may have formed
during the assembly and curing. Don’t go overboard - just make
sure that you have a piece that is flat on all sides so it will slide
smoothly into the ribs during the upcoming steps.
n n Step 7 - Wing Assembly (rear spar)
Now locate two of the 1/8”
square basswood strips, one
SP3 and one SP4 from BP1.
Using these pieces you’ll
make the rear spar, using the
same techniques as you did
for the front spar. Start by
gluing the long edge of SP3
to the basswood strip, making sure it’s straight along it’s length.
Then glue SP4 in place, lining up the scarf joint. Follow it all up with
the other length of basswood glued to the exposed edges of SP3
and SP4. Lightly sand it flat in preparation for the upcoming steps.
n n Step 8 - Wing Assembly (R2/R2A, R4/R4A)
Now locate one R2 from BP1, one
R4 from BP3, one R2A from LP3
or LP5 and one R4A from LP3 or
LP4. Pay careful attention to the
orientation when doing this as
you'll be gluing R2A to the outside
face of R2 (towards the wing tip)
and R4A to the inside face of R4
(towards the wing root). When glued in place, R2A and R4A need to
be perfectly aligned with top and bottom edges of their respective
ribs. Also the rear edge should be just on the edges of R2A and
R4A should be aligned with the rear spar cutouts in each rib.
n n Step 9 - Wing Assembly (wing ribs)
Now locate one complete
set of wing ribs. Stack them
up in order by referring to
the plans. Starting at the
root: R1, R2, R2/R2A, R3,
R4/R4A, R5, R6, R6, R5, R5,
R5, R5 and R7. Make sure
you align them correctly with
the under-side tabs all in the
same direction. Double, triple, and quadruple check that you have
them in the correct order, then when satisfied, push the front spar
into the larger rectangular hole in each rib. The rear spar is pushed
through the smaller rectangular hole towards the rear of the ribs.
n n Step 10 - Wing Assembly (wing ribs)
Now place this “assembly”
onto the wing plan on your
building board and start
to carefully space the ribs
apart so they align with the
plans. Take your time and
use a light touch so you
don’t break off any of the
underside tabs, or crack any
of the ribs. They don’t need to be perfectly aligned yet, but get
them close. Double check that all the ribs are in the right order one
more time as in the next step everything is locked in place, making
this the last time you’ll be able to easily fix any mix-ups. It’s worth
one more look now - trust me.
n n Step 11 - Wing Assembly (wing ribs)
Starting at the tip rib (R7), it’s
time to start gluing things in
place. I like to put a small drop
of medium CA on the bottom of
the underside tabs of this rib to
help lock it in place to the waxed
paper (or you can use pins if
that’s your thing). Also make sure
to use the enclosed triangle that you should have at hand from the
first steps of this build. This ensures that this rib is perfectly aligned
at 90° to the building surface.
Also make sure that the front and rear spar protrude a little from
R7 - maybe an 1/8” or so.
When satisfied, glue the two spars to R7.
n n Step 12 - Wing Assembly (wing ribs)
Now, slowly and methodically work your way towards the root rib,
one rib at a time. Make sure each rib is precisely aligned - the
spars are aligned, and that you firmly glue each rib to both spars.
As you go along, you also might want to place a drop of glue on
the underside tabs on every third or fourth rib to keep everything
aligned with the plans. Continue with this until you have glued the
R2/R2A rib in place. Stop there and move on to the next step.

Construction Manual www.oldschoolmodels.com Page 5
n n Step 13 - Wing Assembly (SPACER)
Locate SPACERs from LP1. These
are just as the name implies -
simply spacers and should NOT
be glued into the airframe at any
point.
Notice that the pre-cut rectangular
spars holes in R3, both R2’s and R1
are wider than the spars that are in
them. This is to allow for the dihedral braces that will be attached
later on. But you need to make sure the spacing is correct when
gluing the spars in place, hence the use of the SPACERs.
Use one SPACER piece as a substitute for the front dihedral brace
first, by sliding it into the holes on the R1, R2 and R3 ribs. This
should push the spar towards the rear of the pre-cut slots. Then
do the same with the other SPACER for the rear spar holes - again
pushing the spar towards the rear of the cutouts in each rib.
n n Step 14 - Wing Assembly (R3)
With the SPACERs in place, carefully align rib R3 and the outermost
R2 rib, then tack them in place to the spars (best to tack glue on the
back side of the spars). Make sure that the SPACERS are not glued
to spars or any of the ribs as they will be VERY hard to remove.
n n Step 15 - Wing Assembly (WH3)
Locate one of the WH3s from LP1.
It’s outer tabs fit into the pre-cut
slots on the back of the R2 ribs as
shown here. Glue it to the outer
R2 rib first, then properly align the
inner R2 rib. Once aligned, glue
that R2 rib in place by tacking it in
place to the back of the spars, and
then glue the WH3 to it as well.
n n Step 16 - Wing Assembly (WH1, WH2, WH4)
Locate WH1, WH2, and WH4 from LP1. Note that
WH1, WH2 and WH4 have a small circle engraved
on one side. This designates the side that should
face R1 because it has a small angle pre-cut into
it. Glue each WH1, WH2 and WH4
to R2 making sure their tabs are
completely inserted into the holes
on the innermost R2 rib.
n n Step 17 - Wing Assembly (R1)
Locate DH-JIG from LP1. This is used to help
align R1 in this step. WH1, WH2, and WH3
already have this angle cut into them, but
you can also use this DH-JIG to further aid
the R1 alignment. Slide each of the tabs from
those WH pieces into the pre-cut holes of R1,
making sure they are completely inserted. When properly aligned
you should be able to double-check it with the DH-JIG.
After everything is aligned, tack glue R1 to the back of the spars,
then also glue R1 to WH1, WH2 and WH3.
n n Step 18 - Wing Assembly (SPACER)
With the ribs all in place, carefully remove the SPACER pieces and
then glue ribs R3, R2 and R1 to the spars. Make sure you do NOT
have any extra glue fouling the holes where the dihedral braces
will slide into.
n n Step 19 - Wing Assembly (R1A)
Locate two of the R1A pieces from
LP1. These are glued into the center
rectangular cutout in WH4 and WH3 as
shown here, pointing towards the trailing
edge of the wing. Make sure they are
firmly seated as the glue cures.
n n Step 20 - Wing Assembly (trailing edge)
Locate one 1/4” square length of balsa
strip. This will be the trailing edge of
the wing. Measure and trim it to length,
leaving about an extra 1/4” or so. Then
carefully slide it on to the back of each
of the ribs and it should be held in place
between the two “fingers/fangs/points”
on the back of each rib. Working from one side to the other, glue
the trailing edge to each of the ribs, making sure that the alignment
of each rib is still spot on.
n n Step 21 - Wing Assembly (leading edge)
Locate one length of 1/2” square
balsa strip. This is the leading edge
of the wing. Measure and trim it to
length, again, leaving about a 1/4”
extra. Working from one end to
the other, glue the leading edge in
place to each of the ribs, making
sure it is firmly seated into the pre-cut, angled slot of each rib.
n n Step 22 - Wing Assembly (trailing edge sanding)
You'll now need to very lightly sand the
trailing edge. Refer to this diagram to
show what I'm on about. The trailing
edge needs just a little sanded off the
rear edge it so it will continue the airfoil
shape. Do this for the top and bottom
surface of the trailing edge.
n n Step 23 - Wing Assembly (CS1, CS5)
Locate one CS1 from BP15 and one CS5
from LP7. CS5 fits into the pre-cut notch
of CS1 as shown here. Before gluing
it place, lightly sand the edges of CS5
where it will contact CS1, so you’ll have
a good fit. When happy with the fit, carefully apply glue to the
two contacting edges of CS5 and attach it to CS1. Apply a bit of
downward pressure along the seams to make sure the joint is flat
along the edges as the glue cures.
n n Step 24 - Wing Assembly (CS1, CS2, CS3)
Take CS1 from the previous step, and locate one CS2 from BP15
and one CS3 from BP16. After trimming, these will all be glued
together to form the top sheeting of the wing’s center section.
Place the CS1 assembly in place on the rear section of the wing,
then place the CS2 on the front edge, simulating how it will wrap
around the leading edge rib curve (temporarily tape in place if that
Sand this lip to
match airfoil

Page 6 www.oldschoolmodels.com Construction Manual
helps). CS3 has purposely been cut
a little long, so you'll need to trim
it to get a perfect fit filling the gap
between CS1 and CS2.
Also note that CS3 has a pre-cut hole in
it. This is to allow the aileron servo wire
to exit. This hole should be positioned
so it’s closer to the root rib (R1).
When satisfied with how it all looks,
remove the pieces and it’s time to
glue them together into a single sheet.
When edge gluing the sheeting pieces together, first make sure
the edges are flat (give a quick, swipe or two with a sanding block).
Then tape the two pieces together with a piece of masking tape.
As you lift the sheeting from the board you’ll see that the tape will
act as a hinge allowing you to put a small amount of adhesive into
the joint. When the adhesive is applied, place the sheeting back
down on the waxed paper, so that it’s flat and apply pressure to
the joint while it cures to make sure it’s flat along it’s entire length.
When cured, you’ll now have a single, longer piece of sheeting.
It’s easier to join the shorter lengths
of sheeting together on a flat
surface. Then when the glue has
cured, glue the sheeting in place
on the wing. Start at the leading
edge and gluing a little at a time.
Press the sheeting firmly against
the ribs and wait for the glue to
cure before gluing the next section
of sheeting - slowly working your way back to the trailing edge,
being careful not to put a bend (warp) in the wing.
n n Step 25 - Wing Assembly (TE)
Locate one TE from BP14. This is
the trailing edge sheeting. Glue
this in place into the “groove”
pre-cut into the rear of each rib as
shown here. Be sure it is glued to
each of the ribs, to the top of the
trailing edge and to the center
sheeting you just applied.
n n Step 26 - Wing Assembly (LE)
Locate one LE from BP14. This is
the leading edge sheeting. Glue
this in place into the “groove”
pre-cut into the front of each
rib as shown here. Be sure it is
glued to each of the ribs and to
the leading edge, and the center
sheeting.
As the sheeting we get can vary in density, you might have to apply
a bit of Windex® glass cleaner to loosen up the grain and allow
it to bend without cracking. Soak the outer side of the wood to
expand the fibers. Now hold it to curvature needed, then use a
hair dryer or covering heat-gun to help “set” the balsa’s bend as it
dries. Once dry, then you can glue it in position.
n n Step 27 - Wing Assembly (remove under-side tabs)
Once the glue has cured it’s time to carefully remove the wing
assembly from the board. Once removed, flip it over and it’s time
to remove all the underside tabs that helped hold the ribs in place.
There’s one in the front and one in the back of each rib. On ribs
R2-R7, these are balsa and easily cut away with a hobby knife. R1
ribs are lite ply and might need a bit more persuasion to remove.
When trimming these tabs, make sure you cut them away just
enough so that the airfoil shape of each rib is not interrupted. On
the trailing edge, this will mean that each tab will be cut away so
the trailing edge sits 1/16” proud of each rib.
n n Step 28 - Wing Assembly (LG1, LG2)
Locate one LG1 and three LG2s from
LP1, LP5 and LP6.
The three LG2s are glued together,
one on top of the other. Make sure that
their pre-cut holes are lined up, and
the three pieces are perfectly aligned
while the glue cures.
Now LG1 is glued to this LG2 assembly.
Before gluing in place, note that the
slot in LG1 is offset and the end of that
slot will align with the hole in LG2, only if correctly positioned. When you
know how it correctly aligns, apply glue to the back side of LG1, then glue
it in position, making sure to keep excess glue out of LG1's slot.
Finally, test fit the LG assembly into the pocket between R2 and R4. Lightly
sand LG's edges as necessary to insure a good fit, then glue it in position.
Make sure it is fully inserted and resting on the cutouts of the R2A and
R4A pieces.
n n Step 29 - Wing Assembly (wing dowels)
Locate the 6” length of 1/4” dowel from the
hardware bag. Cut it in half and round one end
of each dowel, as shown in the photo. An easy
way to do it is to chuck the dowel into a drill,
then spin it against sandpaper, rounding it to a
nice shape.
Now mark and cut a hole into the leading
edge of the wing where the dowel should
be inserted, making sure it is centered on
the leading edge strip. Cut the hole a bit
undersized, then gradually enlarge it until
you get a nice, snug fit. Test fit the dowel
and make sure that it also slips through the
internal WH1 piece.
Place glue on the lower part of the dowel and insert the dowel
through the leading edge and into WH1, leaving approximately
1/3”-1/2" of the dowel exposed.
n n Step 30 - Wing Assembly (CS1, CS2, CS4)
Locate one CS1 one CS2 and one
CS4 from BP15, and one CS6 from
LP7. These are used to create the
center sheeting for the underside of
the wing.
Use the same techniques that you
used when forming the upper
sheeting a few steps back. You’ll
need to trim CS4 to fit between the
gap of the CS1 and CS2.
Also note that CS6 has a pre-cut hole in it. This is where the wing bolt will
go through to attach the wing later on. This hole should be positioned so
it’s closer to the root rib (R1). When this assembly is completed, glue it in
place using the same techniques as applying the top sheeting.

Construction Manual www.oldschoolmodels.com Page 7
n n Step 31 - Wing Assembly (LE & TE)
Locate one LE and one TE from BP14. These are the lower leading
edge and trailing edge sheeting and should be applied in the
same way as you applied the top side sheets.
n n Step 32- Wing Assembly (root, tip sanding)
Take a few minutes to carefully sand away any extra wood that
extends past the root (R1) and tip (R7) ribs. Cut and/or sand as
necessary until any extra spar or sheeting material is perfectly flush
with those ribs.
n n Step 33 - Wing Assembly (TP1)
Locate one TP1 from LP1. This
is glued in place to R7 as shown
here. It should be at 90° to R7
(perpendicular) and all the TP1
tabs should fit completely into
the pre-cut slots in R7.
n n Step 34 -Wing Assembly (T2, T3, T4)
Locate two T2s and T4s from
BP11S as well as two T3s from
BP12S.
Make sure you're using BP11S
& BP12S for the starboard
wingtip - NOT BP11P & BP12P.
Glue the two T2s together to
make a thicker T2 - perfectly
aligned of course. Then do the
same for the T3s and T4s.
Note the etched lines on T2 and
T3. These are alignment guides
for the piece that fits on top of
them. With the wing sitting up-
right, glue T2 on top of TP1 and
up against R7. Then glue T3 on
top of T2, aligning T3 with the
edges guides and up-against R7. Then finally T4 on top of T3,
aligned and up-against R7.
n n Step 35 - Wing Assembly (T5, T6)
Locate both T5s and T6s from
BP11S. Glue both T5s together,
then both T6s together. Then
these are glued to the underside
of TP1, T5 first, then T6 using T5's
etched lines as a guide.
n n Step 36 - Wing Assembly (aileron box)
First we’ll create the mounting
rails for the aileron hatch by
using leftover 1/4” square
basswood you trimmed when
creating the forward spars.
Measure and cut two lengths
that will span the distance
between the forward and arf
spars. With the wing half laid on it’s top, glue these two strips to
the R6 ribs as shown on the plans. These strips should be flush with
the lower-most pre-cut edges of the R6 ribs.
n n Step 37 - Wing Assembly (aileron box - SH1)
Next locate two SH1s from BP15. These are glued to R6’s small
ledges just behind the front spar and ahead of the rear spar. Glue
these, centered across the two R6 ribs as shown on the plans.
n n Step 38 - Wing Assembly (aileron box - SH)
Locate one SH from LP5. This should now fit in the area between the
SH1’s you just installed. If not, lightly sand as necessary to obtain a
good fit. Note that there are 4 holes precut into the corners. With
a 1/16" bit, use SH as a guide to drill the 4 holes that will be used
to attach SH to the wing using 4 of the supplied 2-56 self-tapping
screws. Temporarily attach the hatch in place using these screws.
n n Step 39 - Wing Assembly (aileron box)
Now locate some of the scrap 1/4” square balsa stock trimmed
away from the trailing edge pieces. Cut two lengths that will run
between the front and rear spars. Glue these in position as shown
on the plans - flush with the top surface of SH1, and against the
1/4” square basswood mounts. Do NOT glue them to the SH hatch
as that needs to be removable.
Set the starboard wing half aside and begin work on the port
wing half. Tape the port wing plan and fresh wax paper on
your board. Then follow steps 1 through 39 to complete the
starboard wing half. Once finished, then move on to step 40.
Note that when building the port half that many of the parts will
need to be glued to the opposite side (the WH1, WH2, and the
wing tip pieces for instance). Always refer to the plans to make
sure you’re gluing the parts together in the correct way.
n Step 40 - Wing Assembly (D1, D2)
Locate D1 from LP3 and D2 from LP2. These are the dihedral
braces. Test fit these by sliding them into both of the wing halves,
as shown. They should smoothly push into the gap in the R1, R2
and R3 ribs until each brace is half way inserted. Also make sure
that you insert them both in the same orientation - so they both
point “up” when the wing is held upright.
Carefully sand as necessary so they both slide in as they should,
and allow the root (R1) ribs on both halves to fit flat against each
other, along their entire length.
Once satisfied with the fit, take the wing halves apart and remove
D1 and D2.
Now it’s time to mix up some epoxy and use it to coat the areas
where the D1 and D2 pieces will contact the spars and ribs. Also
coat the entire face of one of the R1 ribs.
When coated, slide all these
pieces back together to form
the completed wing assembly.
Hold these together with some
tape and/or clamps until the
epoxy has cured completely.
While waiting for the glue to
cure, wipe away any excess
with a paper-towel soaked in a bit of denatured alcohol.

Page 8 www.oldschoolmodels.com Construction Manual
nStep 49 - Vertical Fin Assembly (VF8)
Locate VF8 from BP13. Glue VF8 to VF7 and
VF9.
nStep 50 - Vertical Fin Assembly (VF15)
Remove the pins from the vertical structure and
lightly sand the surface to make sure it's smooth.
Now, locate one VF15 from BP18. Glue it in place
over the rear section of the structure, making sure
that it's perfectly aligned as shown here.
nStep 51 - Vertical Fin Assembly (VF16)
Locate VF16 from BP17. Glue this in place
over the front of the structure, again,
making sure it's perfectly aligned and fully
inserted into the VF15 tab.
nStep 52 - Vertical Fin Assembly (VF15, VF16)
Remove the vertical fin assembly and
flip it over. Again, lightly sand the
structure so it's flat.
Then locate the other VF15 from BP18
and VF16 from BP17. Glue these in
place over structure, just as you did for the fin's port side, making
sure the pieces are perfectly aligned.
nStep 53 - Rudder Assembly (VF10)
Locate VF10 from BP13. Pin it in position.
nStep 54 - Rudder Assembly (VF12)
Locate VF12 from BP13. Glue it in place to the bottom
part of VF10.
nStep 55 - Rudder Assembly (VF11, VF13)
Locate VF11 and VF13 from BP13. Glue them
in and pin them in position.
nStep 56 - Rudder Assembly (VF14)
Locate VF14 from BP13. Glue it in position between
VF10 and VF11.
nStep 57 - Rudder Assembly (VF17)
Remove the pins from the rudder structure and
lightly sand the surface to make sure it's smooth.
Now, locate one VF17 from BP17. Glue it in place
over the rear section of the structure, making
sure that it's perfectly aligned as shown here.
n Step 41 - Wing Assembly (ailerons)
Locate the two lengths of 5/16” x 1-1/4” tapered balsa sticks.
These are used as the ailerons. Refer to the plan for the correct
length, then cut one aileron from each piece. Also note the slight
angle on the aileron tips and cut/sand that in as well.
Note - if you prefer to make your Lark a 3-channel system (without
ailerons), you can glue these strips to the trailing edge of each wing
to continue on the airfoil shape of the wing. We’ve not done this
with any of the prototypes as we prefer ailerons, but there could
be a couple of you out there that are aileron-phobic, so here’s your
chance to go really “old-school”.
This completes the assembly of the wing. Now it’s time for the
tail surfaces, starting with the vertical fin.
nStep 42 - Vertical Fin Assembly (prep)
Position the vertical fin plan
over your building surface and
tape into position. Tear off a
length of waxed paper long
enough to cover the plan and
tape that into position.
nStep 43 - Vertical Fin Assembly (VF1, VF5)
Locate VF1 and VF5 from BP13. Pin
VF1 in position, then glue VF5 to
VF1 and pin it in position.
nStep 44 - Vertical Fin Assembly (VF2)
Locate VF2 from BP13. Glue VF2 to VF1 and pin
it in position.
nStep 45 - Vertical Fin Assembly (VF3, VF4A, VF4B)
Locate VF3, VF4A, and VF4B from BP13. Glue
VF3 to VF2 and pin it in position. Then glue
VF4A and VF4B into position as shown.
nStep 46 - Vertical Fin Assembly (VF6)
Locate VF6 from BP13. Glue VF6 to VF3 and pin it
in position.
nStep 47 - Vertical Fin Assembly (VF7)
Locate VF7 from BP13. Glue VF7 to VF6 and
pin it in position.
nStep 48 - Vertical Fin Assembly (VF9)
Locate VF9 from BP13. Note that it has a
small circle engraved, noting it's top edge.
Glue VF9 to VF7 and pin it in position.

Construction Manual www.oldschoolmodels.com Page 9
nStep 63 - Stab Assembly (leading edges)
Locate the other length of
1/4” x 1/2” balsa strip to
use as the leading edge of
the stab. This will need to
be cut to length, and the
root edges beveled slightly
to join correctly at the stab’s
center. Again, using the
“step” cut into the front of
each rib, place these pieces in position and glue them to each of
the ribs, and to each other.
nStep 64 - Stab Assembly (center sheeting, top)
Using the uncut sheet of 1/16th balsa,
it’s time to measure, cut and form
the center sheeting strips that will be
attached to each side of the vertical fin.
These sheets run from the top of the S1
ribs (up against the vertical fin), to cover
the tops of the S2 ribs.
Using the same techniques that you
used when forming the wing’s center
sheeting, measure and cut 3 total
pieces to make each sheet. Take your
time when measuring and cutting -
especially against the tapered edge of the leading edge. What
you want is a piece that fit snugly against the leading and trailing
edges as shown here.
Once you have made a pair of these, glue these in place on each
side over the S1 and S2 ribs, up against the vertical fin as we’ve
shown here.
nStep 65 - Stab Assembly
Remove the stab assembly from your building board and flip it
over. Remove all the underside tabs by trimming them away, just
as you did on the wing. Make sure to continue each of the rib’s
aerodynamic shape.
nStep 66 - Stab Assembly (center sheeting, bottom)
Using the same techniques as you
used on the top sheeting, measure,
cut and form the two strips of 1/16th
sheeting used on the bottom side.
When you are satisfied with their fit,
glue them in position as shown.
nStep 67 - Stab Assembly (ST)
Sand the both ends of the stab assembly
so there’s no extra trailing edge, leading
edge or spar material protruding past
the S7 ribs.
Now locate 6 STs from BP12P and BP12S.
Make 2 tip assemblies by gluing 3 of
them on top of each other, aligned
with each other. Then lightly sand
the long edge so it’s flat, then glue
one assembly to each tip of the stab,
making sure you’ve properly aligned
and centered it on the S7 ribs.
nStep 58 - Vertical Fin Assembly (VF16)
Remove the rudder assembly and flip it over. Again, lightly sand
the structure so it's flat.
Then locate the other VF17 from BP17 and glue this in place over
the front of the structure making sure it's perfectly aligned.
nStep 59 - Stab Assembly (S1 ribs)
Locate both S1 ribs from BP16.
These are glued to the bottom
of the vertical fin assembly from
the previous step, one on each
side. Using the pre-cut holes as a
guide, glue one S1 to the vertical
fin piece, then flip it over and glue
the other S1 to the other side.
Make sure these are properly aligned, and straight with each other.
Refer to the drawing of this section shown on the side view of the
fuselage plans.
Remove the fin plan from your building surface, then cutout and
attach the plans for the horizontal stab and elevator. Cover it
with wax paper and tape everything into place.
nStep 60 - Stab Assembly (SP5, S2-S7 ribs)
Locate SP5 from BP2, and both sets of S2-S7 ribs from BP16. Slide
the vertical fin assembly on to SP5, all the way to the middle.
Then, slide one S2 on each side of SP5, noting the orientation (all
underside tabs pointing the same way, and the leading edges also
oriented correctly. Continue on with both S3s, S4s, S5s, S6s, and
finally S7s. Place this “assembly down on to the plans and begin to
carefully slide the stab ribs into their proper position.
nStep 61 - Stab Assembly (stab ribs)
Using the 90°alignment
triangle, it’s time to
start gluing the stab
ribs to SP5. Start with
the vertical fin, with it
perfectly centered, 90°
to the building surface
and straight. Then
work your way through
one side of the stab, then the other. Take the time to make sure
everything is aligned properly BEFORE you glue it in place, as it’s
just about impossible to fix if things are out of order and glued in
place. When finished, you should have something that looks just
about like this photo.
nStep 62 - Stab Assembly (trailing edge)
Locate one length of the 1/4” x
1/2” balsa strip. Measure and cut
this to length to form the trailing
edge of the stab. Leave an extra
1/4” or so, then glue this in place,
using the pre-cut “step” on the
rear of each rib to help hold it
correctly in place. Make sure you
glue this piece to each of the stab’s ribs.

Page 10 www.oldschoolmodels.com Construction Manual
nStep 68 - Elevator Assembly
Locate the two extra pieces of 5/16” x 1-1/4” tapered edge stock,
as well as the length of 3/16” dowel. Cut the dowel to length, as
shown on the plans. Now measure and cut one elevator half from
each tapered edge balsa piece. Mark and cut the notches into the
leading edge of these elevator halves as shown on the plans. Then
glue each elevator half to the dowel, making sure the entire piece
is perfectly straight and flat.
This completes the assembly of the tail surfaces. Now it’s
time to assemble the fuselage. You won’t need to tape down
the fuselage plan to the board - simply use it as a reference.
However, you may need to put down some fresh waxed paper as
you’ll need it for a few of the steps.
nStep 69 - Fuse Assembly (WH5)
Locate four WH5s from LP4. These are glued
together as shown here, one on top of the
other and properly aligned.
nStep 70 - Fuse Assembly (F3, F3A)
Locate F3 from LP2 and F3A from LP1. Glue
F3A to the bottom of F3 as shown here,
making sure it is properly aligned.
nStep 71 - Fuse Assembly (F5, TR1)
Locate TR1 and F5 from LP2. F5 is
inserted into the slots on each side
of TR1 as shown here, then rests
against the cross-bar in F5.
When satisfied on how this fits,
glue this in place, making sure F5
is perpendicular to TR1.
nStep 72 - Fuse Assembly (FSP, TR1 assembly)
Locate FSP from LP4. The
TR1 assembly from the
previous step is now attached
as shown here. There are
several tabs on the TR1
assembly that need to fit
into the various slots cut into
FSP, so test fit this first. When
satisfied on how it all goes
together, apply glue to the edges of the TR1 assembly, everywhere
it will contact FSP. Glue these two pieces together, making sure
that the tabs are fully inserted in each of FSP's slots.
nStep 73 - Fuse Assembly (FSS)
Locate FSS from LP5. Just as you
did for FSP, test fit this in place
on the other side of the TR1
assembly.
When satisfied, remove FSS,
apply glue and then make sure
it is properly affixed to the TR1
assembly as shown here.
nStep 74 - Fuse Assembly (F4, WH5)
Locate F4 from LP2 and the WH5
assembly you made earlier. These
are both attached towards the rear
of the fuselage box you are creating.
You will have to carefully bend the
sides a little to get them to fit into
the pre-cut slots on the box sides.
Glue these in place.
nStep 75 - Fuse Assembly (F1/F2)
Locate F1 and F2 from LP4. These are glued
together as shown to form the firewall. Make
sure F1 is aligned with F2 and that the etched
nose-gear alignment lines are visible. We
recommend epoxy for this step.
nStep 76 - Fuse Assembly (TR2)
Locate TR2 from LP2 and F2 from
the previous step. Note that TR2
has a small circle engraved on the
top surface - this designates the
starboard side of the fuselage.
Both tabs on the front of TR2
should be inserted into the pre-
cut holes in F2 as shown here. Also
note that this piece is NOT glued
perpendicular to TR1. Instead, use
the DH-JIG guide you used during the wing construction to give
the needed downthrust angle that will become apparent in the
next few step.
nStep 77 - Fuse Assembly (TR2)
The TR2 assembly is now
glued in place inside the front
of the fuselage box, between
the fuselage sides and into
F3A. To do this carefully bend
the fuselage sides apart a bit,
allowing the assembly to slide
into place. When properly
aligned, all of the tabs should
pop into the pre-cut holes on
both FSP and FSS.
When satisfied with this dry fit, remove the tray, apply glue, and
put in back in position. Make sure it’s held in place and that the
fuselage sides continue their gentle curvature that is cut into TR2.
nStep 78 - Fuse Assembly (nose gear block)
This might seem like a strange time to do this, but it’s actually the
perfect time. Inside the hardware
bag is a smaller bag which has all the
components needed to make the nose
gear assembly. In this group of parts is
the nylon nose block, the 4 mounting
screws, and the 4 t-nuts.
Using the etched lines on F1, you can
easily locate this nose-block so it’s
straight, as the lines should appear
inside each of the 4 block’s four
mounting holes. Using a 3/32” bit, drill

Construction Manual www.oldschoolmodels.com Page 11
these four mounting positions into F1.
Then use the 4 screws and t-nuts to fasten this in position. You might want
to use a bit of thread lock and cut away the extra length from interfering
with the tank and/or battery installation later on.
nStep 79 - Fuse Assembly (FS1, FS2, FS3, FS4)
Locate both FS1s
from BP8, both
FS2s from BP7, as
well as both FS3s
and both FS4s
from BP6.
Glue one FS1 to
one FS2, making sure that all the tabs on FS1 are completely seated
into the notches cut into FS2. Also make sure that the pieces are
flat along this entire joint.
Then glue FS3 and FS4 together using the same technique.
Make 2 matching fuselage assemblied.
nStep 80 - Fuse Assembly (fuse side prep)
Now glue one FS1/
FS2 to one FS3/FS4
to make a completed
fuselage side. Again
make sure that all the
tabs are completely
seated into the
notches. Also make
sure that the pieces are flat along this entire joint.
Make the two fuselage sides.
nStep 81 - Fuse Assembly (FS5, FS6)
Position the fuselage sheets next to each other, one mirroring the
other as shown here.
Lightly sand the center joint on
each sheet, then locate FS5 and
FS6 from BP9. These pieces act
as supports for the fuselage
side joints.
Note there are etched lines on
these pieces. These lines are
meant to line up with the joint
lines of the fuselage sides and
they will only align properly one way (FS5 port, FS6 starboard).
When satisfied on how they align, glue them in place to the
fuselage sides.
nStep 82 - Fuse Assembly (STS)
Locate four STSs from BP12S. Glue two STSs together to form a
thicker STS, then do the same for the remaining two STSs so you
end up with two thicker STSs.
These stab supports are glued
in place on the inside of the
fuselage sides to “beef-up”
those areas. Pay attention to
the orientation and make sure
that the curved edges of the
STS pieces are matched up
to the cutouts in the fuselage
sides.
nStep 83 - Fuse Assembly (fuse sides)
Take both fuselage sides and align
them. Using pins and/or tape,
temporarily attach the rear of these
two sheets together as shown here.
This will guarantee that the alignment
of the fuselage doesn't shift as work
will now move towards the front of
the fuselage.
nStep 84 - Fuse Assembly (lite ply box install)
With the fuselage pinned
together, it's now time to offer
up the inner lite-ply box to the
fuselage sides for a test fit.
It's best to do this on your
work surface to make sure box
and fuse sides are all flat with
each other when doing this.
Test fit this first and use the
wing saddle as one of the main
alignment aids. Once you’re
satisfied how these pieces go together, remove the plywood box
and it’s time to glue it in place. If you’re using CA for this step, use
slower curing viscosities as you might need a bit more working
time to properly align the pieces. This is one step where you might
want to use a different glue - aliphatic resin and/or carpenter’s glue
could give you a LOT more working time. Epoxy could be used,
but it can add a bit too much weight with the amount of surface
area to cover on each side of the fuselage box.
Take your time and you might want to use clamps as shown to aid
in getting everything held firmly in place, and making sure that the
fuse sides conform to the gentle curvature designed into the front
of the fuselage.
nStep 85 - Fuse Assembly (F6, F7, F8)
Locate F6, F7 and F8 from BP5.
If you choose to, you can cut long-grain 1/4" wide strips from the
scrap of BP17 and BP18 sheets. Then you can use glue a strip to each
vertical side of these formers to strengthen them. Alternatively, you
could use some thin C/A to wick into these pieces as well. Honestly,
I didn't need to do either on the prototype builds, but if you think
you might break these, now's the time.
Also note that these formers have pushrod guides pre-cut into them.
It makes absolutely no difference which way you choose to mount
them inside the fuse, but whichever way you start with F6, make sure
F7's and F8's holes are aligned the same way.
nStep 86 - Fuse Assembly (F6, F7, F8)
Now, carefully insert F6 into the
fuselage first, making sure the "F6"
etching is towards the top of the
fuselage.
Do the same with F7 and F8. Glue
these 3 formers in place, making sure
that the fuselage remains aligned,
with no twists or bows.
Again, make sure the pushrod guide
holes are aligned for all formers.

Page 12 www.oldschoolmodels.com Construction Manual
You'll need to remove any pins/tape holding the rear of the
fuselage together for the next few steps.
nStep 87 - Fuse Assembly (top stringers)
Place the fuselage upright on your work
surface. Locate two of the 3/16" square x
36" balsa sticks.
These will be glued to the
inner edges of the fuselage sides, starting
at F3 all the way to the back to F8. Trim
them to length and glue them in place,
making sure they are not only glued to the
fuselage sides along their entire length,
but also pressed down onto the plywood
fuselage box and formers.
nStep 88 - Fuse Assembly (bottom, rear stringers)
Flip the fuselage over to work on the
bottom side. Locate two of the 3/16"
square x 36" balsa sticks.
These will be
glued to the inner edges of the fuselage
sides, starting at F4 all the way to the back
of the fuselage sheets. Trim them to length
and glue them in place making sure they
are not only glued to the fuselage sides
along their entire length, but also pressed
down onto the plywood fuselage box and
formers.
nStep 89 - Fuse Assembly (bottom, front stringers)
Using leftover 3/16" square x 36" balsa
sticks, measure and trim two lengths to fit
between the back of F2 to cover the notches
in F3. Glue them in place making sure they
are not only glued to the fuselage sides
along their entire length, but also pressed
down onto the plywood fuselage box and
formers, following the gentle curvature of
the fuselage.
nStep 90 - Fuselage Assembly (creating rear taper)
Work now moves to the rear of
the fuselage to shape the fuselage
sides so they taper together. To
do this, you’ll need to sand away
equal amounts of balsa on the
internal stringers.
Using a ruler and straight-edge, measure and draw sanding-guides
starting at the rear of the top and bottom stringers, tapering in
about 1-1/2”. These marks will show roughly how much wood
should be sanded away on the insides of each fuselage side, so
they will taper correctly. Although you can cut this with a saw or
hobby knife, sandpaper makes quick work of this, but use caution
not to remove too much.
nStep 91 - Fuse Assembly (sand the tail surfaces)
It’s time to attach the tail surfaces, but before you do, take the time
to sand the leading edges of the stab and vertical fin as they’ll be
much easier to do now, than after installation. Make sure that the
leading edges are nicely rounded, and you might want to test fit
them to the rear of the fuselage a few times as you sand, to get
an idea of where you might need a bit more shaping. However, do
NOT round the bottom edge of the fin as this is used to align the
tail assembly to the fuselage.
nStep 92 - Fuse Assembly (attach the tail surfaces)
Once sanded, it’s
time to trial fit the tail
surfaces to the fuselage.
With the fuselage
sitting upright and flat
on your building board,
you can then slip the
tail surface assembly
in place, making sure
that the front of the
stab is inserted into the
cutouts in F7 and F8.
Now, if you take a measurement from the flat of the building board to tips
of the trailing edges, they should be the same distance (giving you a nice,
horizontal stab). If adjustment is needed, lightly sand the taller fuselage
side to lower the higher side.
Once satisfied with the positioning, glue this in place. Again, use the
proper amount of glue, but NOT too much as a little extra weigh there
makes a huge difference when balancing the model later on. Slower
curing CA, aliphatic resin and/or carpenter’s glue is a better choice here.
nStep 93 - Fuse Assembly (pushrods)
Before installing the top and bottom sheeting, now might be a good
time to think about installing the elevator and rudder pushrods. We
typically use Dubro's Laser flexible pushrods the outer red tubing
fits nicely into the pre-cut pushrod guides into each of the formers,
as well as pre-cut pushrods exits on the rear of the fuselage sides.
If you use Dubro's (or a similar type of pushrod system) don’t forget
to glue these tubes in place so they won’t move.
nStep 94 - Fuse Assembly (TS1)
Locate TS1 from BP10. Cut a 1/2"
wide strip of 1/16th balsa (from
the scrap of BP17/18) that's about
2-1/2" long. Glue this as shown
here - half off and half on the rear
edge of TS1.
This will help strengthen TS1
as well as support TS2 (to be
installed later).
Now test fit TS1 in
place on top of the
fuselage, and note
how it fits into the tabs
on F4 and F5, as well
as resting on top of
F3. The side tabs will
fit into the notches cut
into the fuselage sides
and should be flush
with the sides when
installed correctly.
When satisfied on how this fits, remove, apply glue and then attach
in place.

Construction Manual www.oldschoolmodels.com Page 13
nStep 95 - Fuse Assembly (TS2)
Locate TS2 from BP5. As
you've done before, test fit
this in place making sure all
the tabs fit into the notches
and all is flat, clean and neat.
When satisfied with the fit,
remove it, apply glue and
attach it to finish the top
sheeting.
nStep 96 - Fuse Assembly (rudder pushrod exit)
While you still have access to
the inside of the rear part of the
fuselage, it's a good time to cutout
the exit for the rudder's pushrod.
Again, the side it exits will be
dictated by how you installed the
formers and pushrods earlier.
nStep 97 - Fuse Assembly (rear cap sheeting)
Locate scrap 3/32" balsa sheet, make
a small cap piece to cover the upper
part of the fuselage, just aft of the
stab. Glue this in position.
You will need to cut a relief in this
piece to allow the elevator joiner
clearance. It can be done now, or later
on when you are ready to hinge.
nStep 98 - Fuse Assembly (BS1)
Locate BS1 from BP9. As you did
earlier, cut a 1/2" wide strip of
1/16th balsa (from the scrap of
BP17/18) that's about 2-1/2" long.
Glue this as shown here - half off
and half on the rear edge of BS1.
This will help strengthen BS1 as
well as support BS2 (to be installed
later).
Now test fit BS1 in place on top of the fuselage, and note how it fits
into the tab on F6, as well as resting on the bottom of F4. The side
tabs will fit into the notches cut into the fuselage sides and should
be flush with the sides when installed correctly.
When satisfied on how this fits, remove, apply glue and then attach
in place.
nStep 99 - Fuse Assembly (BS2)
Locate BS2 from BP9. As you've
done before, test fit this in place
making sure all the tabs fit into
the notches and all is flat, clean
and neat.
When satisfied with the fit,
remove it, apply glue and attach it
to finish the aft, bottom sheeting.
nStep 100 - Fuse Assembly (lower, front sheeting)
While you have the fuselage on it's back, it's time to install the
sheeting between F3 and
F2. This you will need to cut
yourself from 3/32" sheeting
scrap (plenty to choose from the
various BP sheets).
This sheeting should be cross
grained and will fit snugly
between the fuselage sides - resting on the 3/32" square balsa
longerons.
You can do this in sections, or make up a wider piece and do it all
in one if you want.
When you're satisfied with the fit, glue this in place.
nStep 101 - Fuse Assembly (H2, H3, H4)
Locate four H4s from LP4, as well as H2
and H3 from LP5.
Note the way the pre-cut holes in H2
and H3 are angled. They "pinch/angle"
inward to match the slight curvature of
the fuselage sides. Also H2 has a more
significant angle because it also takes
into account the right thrust built into
the F1/F2 firewall.
Glue two H4 pieces into H3, making sure they are fully inserted into
the slots, as well as being 90° to the surface of H3.
Now the same is done with H2, but H2 also has a top and bottom.
The "H2" etching is the top, so flip it over and glue the H4 pieces
in on the bottom side - again making sure they're completely
inserted and at 90° to the surface of H2.
nStep 102 - Fuse Assembly (hatch notch cutouts)
Use a hobby knife to cut a notch on
each side of the fuselage just in front of
F3 and just aft of F2. These notches are
already pre-cut into the inner plywood
box, but need to be cut into the
fuselage sides. We don’t to this in our
laser-cutting to give a bit more support
to this area while building.
When you've done that, you can then test fit the H2 and H3
assemblies in their proper spot and make sure they fit somewhat
snugly. Lightly sand as necessary to get a proper fit. BUT STEP
AWAY FROM THE GLUE BOTTLE. DON'T PUT ANY GLUE ON
THESE, or it's gonna be trouble.
nStep 103 - Fuse Assembly (H1)
Locate both H1s from BP12P.
Glue one on top of the other
so they're perfectly aligned.
Then you can test fit H1 into
the hatch area, taking note that
it will only properly fit one way.
Lightly sand the front and aft
edges of H1 to get a good fit,
but don't worry about the port
and starboard edges - those
will be attacked later.
When satisfied with the fit of H1, put a few drops of glue on the
top surfaces of H2 and H3 (which should have been sitting in the
fuselage this whole time). Then press H1 down onto these pieces,

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nStep 108 - Electric firewall (E2)
If (and only if) you are powering
your Lark with an electric power
system, now is the time to
install the electric firewall. It is
glued into position as shown
in the photo. You may want to
slightly bevel the left and right
edges to have a better fit to the
curvature of the fuselage sides.
We recommend epoxy for this
step.
nStep 109 - Electric cooling scoop
If (and only if) you are powering
your Lark with an electric power
system, you may want to add an
air-flow scoop to the bottom of the
fuselage, just behind the firewall.
Refer the photo for how we did it.
Simply mark and cut the bottom
sheeting on the three sides. Gently
lift the front edge and then fit two
small triangles to support the sides. You can cut the side triangles
from scrap 3/32” balsa sheet.
Note that we found this sample scoop to be too large. It did a
great job of cooling the batteries and ESC, but it also did a great
job of providing enough airflow to consistently blow the hatch off
at high speeds. Reducing the opening down to about a 1/3rd this
width seemed to be the right size to keep this from happening and
still keep everything cool.
nStep 110 - Electric air exits
If (and only if) you are powering your Lark
with an electric power system, you’ll also
need to cut a few holes in the bottom of
the fuselage for the cooling air to exit.
We recommend this be down on the
underside of the fuse, in the area between
F7 and F8. Refer to this photo as how we
setup our prototypes.
nStep 111 - Tank / Battery compartment fuel proofing
If you're using a glow engine to power your Lark, it is strongly
recommended that you fuel proof the inside of the battery
compartment. As you know, fuel has a nasty way of penetrating
wood, causing it to disintegrate over time. Spray (or brush) this on,
also remembering to protect the underside of the hatch and the
engine compartment (firewall and inside of the fuselage cheeks).
nStep 112 - Sanding
Now is the time to get quite familiar with the sanding tools of your
choice. Take the time to perform a good sanding, rounding the
wing’s leading edge and blending it into the wingtips. Go over the
entire wing, making sure the sheeting is smooth, continuing the
curvature of the wing. Pound out the extra time on those wing tips
to make sure they are smooth, perfect works of art and match each
other exactly.
Push the hatch in place then smooth out the edges of the fuselage.
Because of the 3/32” sheeting and the 3/16" balsa supports
and when the glue cures, you can lift the finished hatch assembly
away from the fuselage.
nStep 104 - Fuse Assembly (magnets)
Locate the 8 magnets from the hardware bag, as you'll use 4 of
them in this step, and 4 in the next.
Inside the tank/battery area, you'll see 4 pre-cut holes in the
plywood side-frames - two on the port side, two on the starboard.
Place a drop of glue inside one of the holes, then push in a magnet
- making sure it is completely flush the plywood side frame, but
take care that you don't damage the outer balsa skin. Do the same
for the other 3 pre-cut holes in this area.
Don't worry about positive/negative poles and attraction - that's
in the next step.
nStep 105 - Fuse Assembly (H4)
Using the 4 left-over magnets, snap each one in place to the
magnets already installed in the fuselage.
Hold the hatch assembly in the same orientation as the fuselage,
then working with 1 magnet at a time, slide it away from it's
matching magnet, already installed in the fuselage. Take care of it's
orientation and push it into the corresponding H4 on the bottom of
the hatch assembly. Each should be a nice, press fit that will hold
them in place fairly well.
Once each of the magnets are pressed in place, dry fit the hatch to
the fuselage and make sure each of the magnets are attracting, not
repelling each other. Fix magnet orientation as necessary.
When you're good with everything, remove the hatch, then carefully
glue each magnet in place, by noting it's orientation, removing it,
applying glue, then pushing it back in to place.
nStep 106 - Electric firewall spacer (E1)
If (and only if) you are powering your
Lark with an electric power system,
you’ll need to also install the electric
firewall pieces which position the
motor a bit further out than a glow
engine needs to be. Locate both
E1s from LP2.
The E1's are probably a little long
for most motor installations, but we
wanted to make sure we covered
as many options as possible. In
the case of using the recommended Innov8tive Designs' Tempest power
system, after measuring from the motor's cross plate to the back of the
spinner, we ended up cutting about 1/2" off the length of each E1. Your
mileage may vary, so do your homework before mounting these in place.
Position these on each side of the front fuselage cheeks as shown in the
photo. When gluing these in place, their notches should be fully inserted
into the slots cut into the sides of F1. Both E1s should be clamped firmly
up against the fuselage sides as well.
nStep 107 - Electric firewall (E2)
If (and only if) you are powering your Lark
with an electric power system, you’ll now
need to locate both E2s from LP3 and
LP5. These are glued together to form a
thicker firewall.
Also take the time to drill and temporarily
install whatever type of mount came with your
motor. It's easier to install the t-nuts now, than
after the firewall is installed.

Construction Manual www.oldschoolmodels.com Page 15
installed inside the fuselage’s rear perimeter, you can put in a little
effort to round the edges of the fuselage if you’d like. Just take
care not to sand off the finger catches on each side of the hatch.
Round the trailing edges of the ailerons, elevator, and rudder. Sand
bevels into the leading edge of both elevator halves, the rudder,
and the ailerons. And speaking of the ailerons, round off the back
outer corners with a nice radius.
The idea is to spend some time caressing this airframe you've
created, smoothing the rough edges until it's something so smooth
that it will flow through the air with ease.
This completes assembly of the Lark airframe. These next few
steps can be done in most any order - up until it's time to cover.
nStep 113 - Fuse Assembly (attach main gear)
Locate both pre-bent main
gear wires, two landing
gear straps and four 2-56
self-tapping screws. Using
a 5/32 bit, run those down
through the holes in LG1
and LG2 to clear out any
excess glue, then push the
main gear wires into place.
To hold them in place,
install the landing gear
straps as shown in the photo. Use a 1/16” drill to make the mounting
holes for the screws, and then attach the straps in position.
nStep 114 - Fuse Assembly (nose main gear)
Everything you need to
assemble the nose gear is in
one package. The nose gear
wire is partially pushed up
through the white mounting
block. Slip the steering arm
in place, then push the nose
gear wire all the way through
the arm and the block. Stop
when the wire is flush with the
top of the mounting block.
With the nose gear positioned
so the coil is towards the rear
of the plane, position the steering arm at a 25-30° angle, then
tighten the set-screw in the steering arm just tight enough so it
should make a mark on the nose gear wire. Loosen the screw and
remove the wire. Grind a small flat on the nose gear where the
screw made a mark, then re-attach. Use a touch of thread-locking
compound on the screw to make sure it doesn't vibrate loose later
on down the road (or more to the point - down the runway).
Power system
Installing your power system of choice is up next. Here's a couple
photos showing sample electric and glow installations. Note that
these are suggestions only as your power system might vary from
our examples.
Glow power
Mounting the engine is a fairly
simple thing. It should mount
upright and use the thrust
lines on the fuselage plans as
a general guide. With the nose
gear block in place, things are
a little tight, so plan this out
before drilling any holes. What
you see in our prototype is an
O.S .30 mounted on a Dave
Brown Products engine mount (now available from Ohio Superstar
as of the time this manual was written). Other mounts will work just
as well - use what's best for you.
A 4-6 ounce tank works well and gives a nice flight time. Again,
plan this out before committing to anything permanent.
Electric power
There's a lot of choices out
there for electric power,
but we've reached out to
Innov8tive Designs for their
recommendations on power.
You'll see those on our
website for both their Cobra
and Tempest brands. What's
pictured here is their Tempest
setup one of our prototypes.
Also, we're big believers in
having an arming switch/
plug when using electric
powerplants of this size.
There's plenty of options out there and it's something to think
about. Remember, in case of an accident, your fingers probably
don't grow back!
Battery Tray (TR4, TR5, TR6) - Optional
Located on LP6 are three parts that make up an optional battery
tray. These pieces can be assembled to "raise" the tank tray up
to the level of TR1. This allows for longer batteries to be installed.
Glue the tabs in TR5 and TR6 into the precut slots in TR4 (they only
fit one way), making sure they're 90° to TR4's surface.
Then this assembly can be glued to the top of TR2, with the tabs
fitting inside TR2's circles (again, only fitting properly in one way).
Before gluing this in place, we chose to install the ESC on TR2 first,
then installing the TR4 tray.
nControl horns, servo & pushrod installation
Although you can install the servos and control hardware after covering
your Lark, we find it easier to temporarily mount everything in place
before covering. This way you have unblocked access inside the
fuselage and wings to get the servos,
extensions, and pushrods in place.
Shown in the following photo if an
example of servo installation in one of
the Lark prototypes. Glue TR3 strips
(from LP2, LP4 and LP5) where the

Page 16 www.oldschoolmodels.com Construction Manual
servos are mounted to thicken the mounting surface for the servo's
screws. If using standard size servos for the elevator and rudder, you
may need to stack the TR3's two-high so the servos will clear things that
might interfere with the servo arms.
Take a bit of time to plan things out, including how you'll run the
throttle and nose gear steering pushrods.
When mounting the servos to each of the SH's you'll need to cut
eight 3/4" lengths of the 1/4" square basswood scrap. Make four
thicker mounting posts by laminating two pieces together then
sand the ends flat.
Position your aileron
servo on the inside of
the aileron hatch so the
servo arm output shaft is
centered in the opening.
On the inside of each
aileron hatch, glue one
post on each side of the
servo as shown in the photo.
Note that the left hatch is a mirror
image of the right hatch.
Now fit the servo hatches into
position on the bottom of the wing.
Using the pre-cut holes as a guide,
drill four 1/16” mounting holes into
the basswood mounting posts you
just installed. Harden the wood with
a bit of thin CA and you can use the
supplied 2-56 x 3/4” self tapping screws to secure the hatches in
place.
Finish the layout of your radio gear by adding the receiver, flight
pack battery and the switch. We mounted the receiver to the
tray by using a bit of self-adhesive hook-and-loop (not included).
The radio's switch should be mounted to the opposite side
of the muffler (to help keep the goop out of it). Or, for an even
cleaner installation, it could be installed inside the tank/battery
compartment - hidden under the hatch - VERY NICE!
Covering
Now it is time to cover the Lark. Remove the powerplant, main
gear, nosewheel assembly, pushrods, and any other components
that would get in the way of applying the covering.
Double check that all surfaces are smooth and ready to cover. Sand
as necessary, then cover the entire airframe with the covering/finish
of your choice.
Note that if you’re powering with an electric motor, you’ll need
to make a hole for the cooling air to escape the bottom of the
fuselage, near the rear.
When the covering is complete, re-attach all the components you
removed earlier in this step.
Logos, numbers, etc.
If you want to use graphics similar to the
ones we used, Old School Model Works
has teamed up with Callie Graphics as a
supplier for pre-cut vinyl. They are a very
well known provider of custom graphics for
R/C models.
We have supplied them with the artwork
needed to cut the correct size logos. You can order straight from
them, choosing the colors that work for you.
Contact Callie Graphics at this link: https://callie-graphics.com or scan
the QR code.
Note that Callie Graphics is not affiliated with Old School Model
Works, nor does Old School Model Works generate any income
from this partnership.
Attach the Control Surfaces
Now is the time to attach all the control surfaces to the airframe, by
gluing the hinges in position with thin C/A. We've noted suggested
hinge locations for each of the control surfaces on the plans.
When using the CA hinges, first push a
pin through on side, at the center of the
hinge as shown here. This will keep the
hinge centered as it's pushed into the
surfaces. When you've got all the hinges
for a surface in place, then remove the
pins and glue the hinges.
Make sure that you attach the elevator
first, and make sure you cut away some
clearance to allow the elevator joiner to rotate freely and not
interfere with the fuselage.
When the elevator's in place, then attach the rudder.
And don't forget the ailerons.
Attach wheels
Use the included 5/32” i.d. wheel collars to hold each wheel (not
included) on the axles. For a maintenance free installation, file
a small flat on the axle where the set screw of the wheel collar
touches. Also use a touch of thread-locking compound to keep the
screw from loosening over time.

Construction Manual www.oldschoolmodels.com Page 17
Optional canopy
Included is a canopy and
though it's certainly up to you
if you choose to use it, the
canopy is just a defining part
of the Lark's' outline, so why
not use it?
The following steps will
describe how to properly prepare and attach it.
• Trim along it’s flat edge. You’ll want to trim away the excess
plastic and leave a smooth lip, roughly 3/16” wide around the
it’s perimeter.
• Place it on the fuselage and make sure it's lays flat on the top of
the sheeting. Not all canopies are exactly identical, so a bit of
trial and error is needed to get a good fit.
• If you’re going to add a pilot figure (not included), now is the
time to test-fit, then glue it in place.
• Give the canopy a quick wash in warm, soapy water.
• If you're going to tint or paint the canopy, do this on the inside
now and allow it to try.
• Use a bit of canopy glue to attach the canopy. So it doesn't
move while the glue cures, hold it in place with a bit of low-tack
masking tape.
This completes the assembly of the Lark. Now you’ll need to
adjust the control throws and check for balance.
Recommended C.G. setting:
An important part of preparing the aircraft for flight is properly
balancing the model. This is especially important because of the
various motor/battery combinations that can be used.
CAUTION! DO NOT SKIP THIS STEP!
The recommended Center of Gravity (CG) range for the Lark is 3.1"
from the leading edge of the wing, and you’ll see this marked on
the fuselage plan with this symbol.
If necessary, move the battery, receiver,
and/or add weight to either the nose
or the tail until the correct balance is
achieved. Stick-on weights are available
at your local hobby store and work well
for this purpose.
We recommend balancing it at the
forward point for the first flights, then moving it backward if you'd
like it to be a little more maneuverable.
Recommended Control Throws:
The amount of control throw should be adjusted as closely as
possible using mechanical means, rather than making large
changes electronically at the radio.
By moving the position of the clevis at the control horn toward
the outermost hole, you will decrease the amount of control throw
of the control surface. Moving it toward the control surface will
increase the amount of throw. Moving the pushrod wire at the
servo arm will have the opposite effect: Moving it closer to center
will decrease throw, and away from center will increase throw. Work
with a combination of the two to achieve something relatively
close to these throws that are good for everyday sport flying. If
competing in pattern, you'll probably want to dial these down a bit
to give a smoother appearance to your maneuvers.
Aileron 3/8” up/down (25% expo)
Elevator 1/4” up/down (20% expo)
Rudder .75” left/right (15% expo)
(Expert tip: Once the control throws have been set, cut a few
pieces of medium silicone fuel tubing (or heat shrink tubing) to
go around each of the clevises. This will keep them from opening
during ight.)
Preflight:
Charge both the transmitter and receiver pack for your airplane.
Use the recommended charger supplied with your particular radio
system, following the instructions provided with the radio. In most
cases, the radio should be charged the night before going out
flying.
Check the radio installation and make sure all the control
surfaces are moving correctly (i.e. the correct direction and with
the recommended throws). Test run the engine and make sure it
transitions smoothly from idle to full throttle and back. Also ensure
the engine is tuned according to the manufacturer’s instructions,
and it will run consistently and constantly at full throttle when
adjusted.
Check all the control horns, servo horns and clevises to make
sure they are secure and in good condition. Replace any items
that would be considered questionable. Failure of any of these
components in flight would mean the loss of your aircraft.
Range check your radio before flying
Before each flying session, range check your radio. This is
accomplished by turning on your transmitter with the antenna
collapsed. Turn on the radio in your airplane, but do not attach the
arming switch.
With your airplane on the ground, you should be able to walk 30
paces away from your airplane and still have complete control of
all functions.
If not, don’t attempt to fly! Have your radio equipment checked
out by the manufacturer.
Warranty Information
Old School Model Works guarantees this kit to be free from defects in both
material and workmanship at the date of purchase. This warranty does not cover
any parts damage by use or modification. In no case shall Old School Model
Works’ liability exceed the original cost of the purchased kit. Further, Old School
Model Works reserves the right to change or modify this warranty without notice.
In that Old School Model Works has no control over the final assembly or
material used for the final assembly, no liability shall be assumed nor accepted for
any damage of the final user-assembled product. By the act of using the product,
the user accepts all resulting liability.
Limit of Liability
In the use of this product, our only obligation shall be to replace such quantity
of the product proven to be defective. The user shall determine the suitability
of the product for his or her intended use and shall assume all risk and liability in
connection therewith.
If the buyer is not prepared to accept the liability associated with the use of this
product, the buyer is advised to return this kit immediately in new and un-opened
condition.
As of this printing, you are required to register with the FAA if you own this product.
For up-to-date information on how to register with the FAA, visit
https://registermyuas.faa.gov .
For additional assistance on regulations and guidance of UAS usage, visit
http://www.knowbeforeyoufly.org .

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