Bantam Instruction Manual

Bantam
tm
Instruction Manual
©2002
These instructions cover the construction of both the Bantam and
the Bantam Bipe. Both aircraft are Slow Flyer/Indoor Flyer aircraft
designed for calm winds outdoor flying or indoor flying. Both have
been very successfully flown in the area of a single basketball court
about 95’ by 75’. As the construction of both kits is very similar,
we’ll refer to both kits as the “Bantam” and note any differences in
construction where necessary.
The Bantam and Bantam Bipe both use the power system and
radio system that's typically used in the GWS Pico Stick, Cub, or Tiger Moth. If you've busted up one of the GWS airplanes, you can
move everything right over to a Bantam or Bantam Bipe. If you don’t
have the necessary parts for a power system or onboard radio system,
we stock them at SR at special prices for Bantam and Bantam Bipe
builders so give us a call.
The Bantam has a 39" wing span and 210 square inches of wing
area. All up weight, ready to fly, is 8 ounces. The Bantam Bipe also
has a 39" wing span, but because of its two wings, it has a wing area
of 380 square inches. All up weight, ready to fly, is 8.8 ounces! Both
ships can be flown very slowly, but the Bantam Bipe is by far the
slower of the two because of its lower wing loading.
No kidding! Please read this!
We know you’ve been told a million times to read the instructions, but this time you really should. The Bantam and Bantam Bipe
employ construction techniques that may be new to you. Nothing
about building the Bantam or Bantam Bipe is difficult, but because of
the lightweight construction and materials you have to be a little more
careful with your building techniques. If you do mess up, give us a
call. We promise not to holler at you. But, why not do it right the first
time and follow the instructions? You’ll save a lot of time if you do.
We used thin, fast setting, CA glue in assembling all of the Bantam and Bantam Bipe prototypes. If you need any of the building
tools or materials shown in this instruction manual, again, give us a
call and we’ll be glad to help select the right tool for the job.
Now, lets get building. We’ve actually built a Bantam, ready to
cover in two hours so this is going to go very quickly!
Bantamm Instruction Manual, Page 1
Recommended Power Systems...
If you already have a GWS DXA motor and gearbox, it’s
perfect for the Bantam and Bantam Bipe. If you don’t already
have a GWS power system, we recommend the MPI EPU6
motor/gearbox. A 9x4.7 prop will work well and a 10x4.7 will
allow you to slow down a little so you might want to experiment with it. We’ve tested a bunch of the micro speed controls and the Jeti 050 is our favorite. It has the smoothest
power response and the least drop in power due to speed control resistance. For battery pack, we suggest an SR 150 Series,
7 cell flat pack with JST connector. We have a special package price on this complete system for Bantam builders.
Recommended Airborne Radio Systems...
Picking the right servo is easy. We’ve recommended the
MPI MX50HP servo for a long time for our Cutie kit. It’s
very fast, powerful, and it only weighs .32 oz. There are a few
lighter servos, but they are no where near as fast and powerful
and they cost a lot more. We like the idea of being able to use
the servos over again in a larger ship later on if you like. For
receiver, the 1/4 ounce MPI 6800 is terrific. It’s extremely
small and light and although it has a short antenna, unlike
other receivers with shorter antennas, it has more than enough
range. Up to 1000’! We also have a special package price on
this complete system for Bantam builders.
Finding the parts...
We’ve included master parts sheets at the end of this instruction
manual that identify each part in the Bantam kit. They will make it a
lot easier to find the part for which you’re looking. There’s a separate
parts sheet for the Bantam and Bantam Bipe. Make sure you’re looking at the right one!
Cutting the parts free...
We’ve left all of the MicroLaser Cut parts for the Bantam in their
sheets to protect them. To make it easier for you, just about all of the
cuts will be with the grain and you’ll notice that the tabs are usually
in a line from top to bottom across the 3” width of the sheet. We suggest that you leave the parts in their sheets until you’re ready for
them. Variations in wood density will sometimes cause parts to not
quite be cut all the way through. If you find any of the parts aren’t cut
all the way, just complete the cut on the back of the sheet.
Bantamtm Instruction Manual, Page 2
Bantam
Bantam Bipe
Sanding...
In most cases, the SR MicroLaser Cut process leaves the balsa
parts with a honey colored edge that needs no sanding. Unfortunately,
the glues used in making plywood tend to glaze the edges of the
plywood parts when they are laser cut. We use a special plywood that
is designed for laser cutting, but we recommend that all plywood
parts be lightly sanded along their edges before gluing the parts in
place. In addition, like spruce, plywood parts tend to have an oily film
on their surfaces which prevents CA glues from taking a good hold.
For this reason, we recommend that all plywood parts be given a light
sanding on all surfaces before you glue them in place. We strongly
recommend the Midwest permanent, tungsten carbide, sanding blocks
which come in fine, medium, and coarse grits and even include a
brass cleaning brush. We stock them at SR if your hobby shop doesn’t
have them. They’ll make building your Bantam a lot easier and faster.
Midwest permanent tungsten carbide sanding blocks come
in fine, medium, and coarse and include a cleaning brush
Let’s build a wing...
The wings for the Bantam and Bantam Bipe build exactly the
same way. Group all of the parts for a particular wing panel. You’ll
have two groups for the Bantam and four for the Bantam Bipe.
For each half of the Bantam’s wing and upper wing of the Bantam Bipe, you’ll need five R1 ribs, one R2 rib and one R3 rib. You’ll
also need one trailing Edge (TE), top and bottom main spar (the top is
longer), two turbulator spars (the forward one is shorter), two leading
edge (LE) strips that will be laminated together, and the wing tip
plate. Building the Bipe’s lower wing is the same, just one rib bay
shorter.
Tip Plate
R2
R3
R1
LE
TE
Turbulators
Main Spar
Lightly sand the edges...
If you’re going to use transparent covering material, lightly sand
the edges of the parts that will show through the covering. Be gentle.
It’s easier to sand away the brown edges before the piece is glued into
place.
Bantamm Instruction Manual, Page 3
We’re going to build a left (upper) wing panel...
Use wax paper over the plans to prevent the parts from sticking
to the plans. Pin down the Trailing Edge over the plans. A flat building board is nice, but don’t make yourself crazy getting a surface
that’s perfectly flat. You’ll be able to remove just about any warp or
twist during the covering of the wing.
“T” Pins
Trailing Edge
Wax Paper
The Main Spar...
The shorter of the two spars is the lower spar. Its notches should
face upwards. Line up the notches with the ribs on the plan to make
sure you have the notches facing the right way.
Upper Main Spar
Lower Main Spar
Don’t reach for the glue yet...
Slip the ribs into the notches in the lower main spar. Don’t glue
anything to anything, just dry fit the parts. Notice that R3 is marked
with dashed lines that will be cut away later on. R2 is the thicker,
3/32” rib.
R1
R1
R1
R2
R3
No Glue Yet!!!
Bantamtm Instruction Manual, Page 4
Position the upper main spar...
Slip the notches in the upper main spar into the notches in the
ribs. DON’T GLUE ANYTHING YET!!!
R2 is thicker, 3/32”
The root rib, R3, will be
angled back a little
Make sure the spars
are fully seated
The rear turbulator...
Dry fit the rear, longer, turbulator into the notches in the ribs
closest to the main spar.
The rear turbulator spar
is the longer one
The front turbulator...
Dry fit the front, shorter, turbulator into the notches in the ribs
closest to the leading edge of the ribs. Still, no glue!
The front turbulator spar
is the shorter one
Bantamm Instruction Manual, Page 5
The tip...
Here’s what the tip should look like. Remember, no glue yet!
The front turbulator
The upper main spar
The rear turbulator
The lower main spar
The upper main spar
Finally, some glue...
Start gluing at the trailing edge. Hold the rib lined up with the
plans and tack glue the rib to the trailing edge. Do all the ribs. Press
down and back a little for a perfect, gapless fit with the trailing edge.
Now, for the spars...
Keep the ribs lined up over the plans and make sure the spars and
turbulators are fully seated in the notches in the ribs. First, glue the
main spar to the ribs and then the turbulators. Don’t glue the root rib,
R3, into place yet. Just do the rest of the ribs. Press gently on each
joint before you glue it into place. Remember to glue the lower main
spar to the ribs too.
Bantamtm Instruction Manual, Page 6
Now the root rib...
Before you glue the root rib, R3, into place, make sure it’s fully
seated up against the notches in the main spars and the turbulator
spars. The root rib should be laying back at an angle which will later
form the wing’s dihedral. Glue the root rib into place.
Laminating the leading edge...
Take a piece of wax paper, about 1” wide and the length of the
leading edge, and fold it in half down its length. Run the fold through
your fingers forming a sharp crease.
Position the wax paper...
You’re going to use your building board and the trailing edge to
form a fixture for laminating the leading edge pieces together. The
wax paper will prevent you from gluing the leading edge pieces to the
wing’s trailing edge.
Position the “L” shaped piece of wax paper up against the trailing
edge. Use pins to hold the two leading edge pieces up against the
trailing edge, but don’t put the pins through the leading edge pieces.
Just position the pins up against the leading edge pieces. Make sure
that the wax paper is between the leading edge pieces and the trailing
edge and building board. The joint between the two leading edge
pieces should be facing up.
Two leading edge pieces
with the joint facing upwards
Wax paper “L”
Bantamm Instruction Manual, Page 7
Glue the leading edge pieces together...
Press down on the leading edge pieces and press them up against
the trailing edge. Tack glue the two pieces together a few inches
apart. If everything looks good, wick glue into the joint down the entire length of the leading edge. When the glue has set, remove the pins
and leading edge from the building board.
Position the leading edge...
If at all possible, turn your building board around so that you’re
facing the leading edge of the wing. Line up the leading edge with the
outer edge of the tip rib. Make sure the joint between the two leading
edge pieces is facing downwards so that it can’t be seen from the top.
Don’t worry about any overlap at the root rib because you’ll be able
to sand it flush a little later on.
The joint is
underneath
and hidden
Glue the leading edge into place...
Start at the tip and glue the leading edge into place as it meets
each rib. Make sure the leading edge is seated properly in the
“mouth” of each rib before you glue the leading edge into place.
Bantamtm Instruction Manual, Page 8
The leading edge is
flush with the tip rib
Prepare the tip...
Sand a bevel on the wing tip plate so that it will make better contact with the bottom edge of the tip rib. MAKE SURE YOU SAND
IT THE RIGHT WAY! Shown, is the tip plate for a LEFT wing tip!
Dry fit the wing tip plate...
After beveling, position the wing tip plate. It should be flush
against your building board, the lower edge of the tip rib, and with the
trailing edge of the wing. Carefully, fit the main spar and turbulator
spars into the notches in the tip plate. Raise the outer edge of the tip
plate until it lines up with the top surfaces of the spars. The spars
should extend past the edge of the tip plate. Don’t panic if you break
something. Try not to, but if you do, just glue it back together. Also,
don’t worry about the gap at the leading edge. We’ll take care of it in
a moment.
Glue the wing tip plate into place...
When you’re happy with the fit, press downward on the tip plate
so that it makes good contact with your building board and glue the
tip plate to the tip rib.
Next, glue the upper main spar and turbulators to the tip plate.
Bantamm Instruction Manual, Page 9
Let’s see if you can avoid gluing your fingers together...
Gluing small pieces together is tough. To make it a little easier,
line up three of the small triangles that will make up the leading edge
filler block at the tip and put a pin through them to be used as a handle. Use a little glue to glue the three pieces together.
Position the leading edge filler block...
Again, using the pin as a handle, position the block so that it’s
almost flush, but not quite, with the leading edge of the leading edge
and so that it’s seated between the tip rib and tip plate as shown. The
sharp point on the leading edge will be sanded back so there’s no
point in lining up the filler block with the very front edge of the leading edge.
Glue it into place...
When you’re happy with the fit, glue the filler block into place.
Bantamtm Instruction Manual, Page 10
Sand the tip...
Remove the wing half from the building board and sand the spars
flush with the wing tip.
Shape the leading edge...
Sand the leading edge to shape.
Shape the leading edge at the tip...
With your sanding block, blend the wing tip up into the leading
edge as shown.
Sand the root rib...
With your sanding block, sand the root rib so that it is flat and
none of the spars, leading edge, or trailing edge are protruding past
the face of the rib.
Bantamm Instruction Manual, Page 11
Trim the root rib...
You’ll notice that we’ve already started the cuts for you in the
root rib. Just follow the dashed lines and remove the narrow strip in
the root rib.
Prepare the wing joiner...
Sand the edges of the plywood wing joiner to make sure there are
no burrs and that they are smooth.
Position the wing joiner...
Insert the wing joiner into its slot in the root rib. Make sure the
bottom of the joiner is flush with your building board, the top of the
upper main spar, and rib R2.
Bantamtm Instruction Manual, Page 12
Glue the wing joiner into place...
Make sure the wing joiner is flush up against the main spars and
rib R2. When you’re happy with its positioning, glue the wing joiner
into place.
Listen up...
!
If you’re building the Bantam, it’s time to build the other wing half. If you’re building the Bantam Bipe, it’s time to build
the second half of the upper wing and both halves of the lower wing. Naturally, only one plywood wing joiner will be used
for each comp lete wing, so just leave the slot in the second wing half empty until we join the wing halves in the next step.
Now, experience has shown us that no matter how many times we tell you not to build two left wing halves instead
of one right and one left, you’re going to do it anyway! If you’ve read this before starting the second wing half, you have a
fighting chance at getting it right. If you’re reading this after you’ve already made the mistake, you can’t say we didn’t
warn you (we have wing kits available so if you’ve built two rights. You can now order a wing kit and build two lefts so
that you’ll at least end up with two usable wings. The only thing that makes a wing a right or a left is the way the main
spars are located in the very beginning of the building process. As before, dry fit the entire second wing panel and take a
good look at it before you start gluing anything and make sure you’re doing what you want to do!
Joining the wing panels...
Hold the wing panels vertically. Carefully insert the plywood
wing joiner into the second wing half. Use your finger tips to feel
how the wing halves are lining up with one another. Are the leading
and trailing edges lining up with each other? Do the two root ribs fit
snuggly up against one another. If you’ve been careful, it should be a
perfect fit.
Start gluing the panels together...
Hold the wing panels together so that they fit snuggly up against
one another. The plywood wing joiners will hold everything in alignment. Tack glue the panels together only at the edge of the trailing
edge.
Bantamm Instruction Manual, Page 13
Tack the wing halves at the leading edge...
Line up the root ribs so that they are a perfect match to one another. When you’re satisfied with the fit, tack glue the two together at
the leading edge.
Glue the wing joiner to the spars...
Now that the wing halves are aligned at the leading and trailing
edges, you can pull the wing halves together in the center. Make sure
the plywood wing joiner is flush up against the main spars in the second wing half and that it’s flush up against rib R2 in the second wing
half. When you’re happy with the fit, glue the plywood joiner to the
main spars and rib R2 in the second wing half.
Glue the root ribs together...
The two root ribs should be flush up against one another so it’s
now time to run some glue around the edges of the ribs, both top and
bottom.
Bantamtm Instruction Manual, Page 14
Your wings are done...
If you’re building a Bantam, your wing is done. If you’re building a Bantam Bipe, join the two lower wing halves just the way you
did with the top wing. When you’re done, this is what you’ll have
It’s time to listen up again...
At this point you only have about an evening of building time into your Bantam or Bantam Bipe. As you’ve found out, the
wings build very quickly. The fuselage goes together just as quickly so let’s get building so that you can get to flying!
Just as with the wing halves, the fuselage sides have a right and a left. Don’t build two right fuselage sides! We’ve
labeled the balsa sheets that hold the fuselage sides to help you tell the right from the left. Another way to tell them
apart is that the hole in the tail for the pushrod to exit through is higher in the right fuselage side. Please take your time
and do it right.
!
Layout and identify the parts...
It’s not a bad idea to lay out all of the parts before you begin.
Identify all of the parts for a right or left fuselage side and keep them
separate.
Right
Left
Bantamm Instruction Manual, Page 15
Prepare the fuselage sides...
Using a sanding block, clean the mating edges of the upper and
lower fuselage sides where they meet. Don’t remove a lot of material,
just clean the edges.
Join the upper and lower fuselage sides...
Working on your building board covered with wax paper, trial fit
the upper and lower fuselage sides together. If they are positioned
properly, they will meet at the windshield and form a perfect straight
line. Have the inside of the fuselage side facing up so in the photo,
we’re working on the right fuselage side.
Tack glue the parts together and then run a very thin bead of glue
down the seam between the fuselage halves.
Left
Right
Add the wing saddle...
Be careful lining up the wing saddle with the top edge of the fuselage and the windshield area. In the photo, we’re working on the
left fuselage side.
Left
Bantamtm Instruction Manual, Page 16
Here’s what you’ve got...
If you’re building a Bantam, at this point you have a right and
left fuselage side, each with a wing saddle glued in place. If you’re
building the Bantam Bipe, you have one extra piece on each fuselage
side, a lower wing saddle. Again, be careful lining it up before you
glue it into place.
Left Bantam
Left Bantam Bipe
Prepare the right angle gauge...
Because of the small uncut tabs that hold the pieces into the larger sheets, you’ll have to lightly sand the inside edges of the right angle gauge before you can use it. Just remove any rough spots.
Insert formers F2 and F3 into the notches in the fuselage sides.
Don’t forget to slide the servo rail into the holes in the formers. The
uncut surface of the servo rail should be up against the fuselage side.
Because of variations in wood thickness, you may have to do some
adjusting to make everything fit snuggly.
Notice how the formers are oriented. Don’t glue them in upside
down! F2 has the smaller hole near the bottom of the fuselage and F3
has a “V” cut in its upper edge for the wing’s dihedral. Use the gauge
to hold the formers square to the fuselage side and tack glue the formers in place. See the next page for information about the Bipe.
Left side
“V” notch for dihedral
Servo Rail
Add the firewall...
Just as with F2 and F3, use the gauge to align the firewall and
glue it in place. Notice that the hole for the battery pack is near the
bottom of the fuselage side.
Bantamm Instruction Manual, Page 17
All formers in place...
Here’s what the Bantam and Bantam Bipe should look like at this
point with all three of the formers in place.
Bantam
Bantam Bipe
Add the other fuselage side...
Turn over the fuselage side you’ve been working on and insert
the tabs in the formers into the notches in the other fuselage side.
DON’T FORGET TO INSERT THE SECOND SERVO RAIL
INTO THE HOLES IN THE FORMERS! Add a weight to hold the
assembly together, but don’t glue anything yet.
Notice that we’re using the right angle gauge to check how close
the two fuselage sides are to being perfectly parallel to one another.
There’s more detail in the next step.
Check the fuselage alignment...
Use the right angle gauge to check the fuselage alignment. With
the gauge standing on your building board, how close are the fuselage
sides to the gauge? With the gauge touching one of the fuselage sides,
the other should be no more than 1/16” away from the gauge. If it
isn’t, twist the fuselage assembly until it is. When you get it right,
tack glue the second fuselage side to the formers. If everything still
looks good, do a final gluing of all of the formers to both of the fuselage sides.
Bantamtm Instruction Manual, Page 18
Organize the top and bottom sheeting...
The bottom sheeting consists of constant width pieces which are
positioned forward on the fuselage bottom and tapered pieces which
start around the middle of the fuselage and go to the tail. The fuselage
top sheeting is all made up of tapered pieces. For the Bipe, the bottom
sheeting is different with constant width pieces in front of the bottom
wing and tapered pieces behind the wing. At his point, you want to
separate the sheeting groups and get them in the right order.
The beauty of laser cutting is that the right side edge of one piece
will exactly match the width of the left edge of the piece adjacent to
it. Carefully put the parts in order and make sure they are right before
you continue. Check the edges where the sheets will mate and use
your sanding block to remove any protrusions, but try not to sand the
edges much as they are perfect the way they are.
Bottom Sheeting
Top Sheeting
Glue the landing gear plate in place...
Position the plywood landing gear plate between the fuselage
sides and up against former F2. Make sure it’s flush with the bottom
edge of the fuselage sides. When it’s right, glue the plate into place.
Attach the first piece of bottom sheeting...
Position the first piece of constant width bottom sheeting so that
it lines up with the fuselage sides and the forward face of the firewall.
When you have it positioned properly, glue the sheet into place.
Bantamm Instruction Manual, Page 19
Poke holes through the bottom sheeting...
From the inside, make sure the plywood landing gear plate is
glued to the bottom sheeting. Then, using a pin or piece of wire, poke
a hole through the bottom sheeting under each of the six holes in the
landing gear plate. Use a drilling motion rather than just forcing the
wire through so that you don’t rip big sections of the bottom sheeting
out.
Open the holes up from the other side...
Turn the fuselage over and open up the holes so that they are
easy to see. Just put the wire or pin in the hole and work it around in a
circle
Add the top forward cowl sheeting...
Position the top forward cowl sheeting. If you want to be neat,
glue it into place from the inside so that it won’t show through transparent covering. If you don’t use a lot of glue, you can glue it from
the outside too. Make sure you glue the sheeting to the top edge of the
firewall too.
Bantamtm Instruction Manual, Page 20