BUILDING THE STEALTH PLATTER 1/2 A TRAINER
Designed by Heman Lee Engine: Cox Black
Window .049 or Norvel Bigmig Startup .049
You
may use these plans freely for non-profit use only!
Parts List
1
Foam
Board 3/16"
1
Lead-out
Guide
2
Plywood
1/16 X 1 1/4 X 12
1
4-40
X 1/2" screw, #6 Washer and blind nut
1
Balsa
Sheet 1/8" X 3" X 36"
7
Screws
2-56 x 3/4 and washers
1
.055
(1/16") music wire, .078 (5/64") music wire and 3 Plastic Wheels
9
Nuts
2-56
1
T-Angle
Motor Mount
1
Control
Horn
1
Lead
Weight 1/4 oz
1
Bell-crank
& Spacer
1
.055
X 9" Pushrod Wire
1
Cox
Black Widow with Cox 6 X 3 prop.
Tools Needed
Titebond Wood Glue
or Epoxy.
Model airplane dope (clear and black).
Xacto Hobby Knife
or Razor Knife.
Sand Paper - 150, 220, 400.
Ruler and 60/30 Triangle.
Pliers
with wire cutter.
C-Clamps and some heavy weights (Brick or frying pan).
Electric
or Cordless Drill.
Black paint.
Updates:
I moved the leadouts and bellcrank 1" further back from previous plans.
Add
more tip weight from 3/8 to 1/2 oz.
Removed 1/2" area from left elevator
to prevent model from rolling inward.
I would put a bigger wheel on the
front nose to prevent tipping over on takeoff.
How to Outline the
Stealth Platter
Tail Fins
Building Instructions
Step 1. - Cut Parts
Cut the foamboard and all balsa parts according to the outline directions. Cutting
2 plywood doubles 1/16 X 1 1/4 X 12" in length. Cut
the tail fins and elevator part from the 1/8" sheet of balsa.
Step 2. Fill Foam Edges Use the flat edge of a scissors
to crimp the edge of the foam to create a slight taper airfoil. Fill
all of the edge of the foam with Titebond glue. This will seal the foam
from being exposed when painting.
Step 3. - Elevator Epoxy a connecting
rod using 1/16" steel wire, so both elevators move as one piece. The
center elevator will remain stationary. Use scrap of nylon or fiberglass
tape and epoxy to reinforce the connection.
Step 4 Center Section
The center triangle section does not move!
Bevel the center triangular
elevator so the connecting wire is not in the way of the movement.
Step 5 Elevator Assembly Assembly the elevator as shown.
Do not hinge or glue anything at this point.
Step
6 - Doublers
Glue the plywood doublers to the top and bottom. Make
sure the doublers are exactly in the center on both side. Use a clamp
or heavy object to clamp down the doublers and let it dry over night.
NOTE:
The elevator connecting rod is sandwich between the top and bottom plywood doublers.
Step 7 Hinge the Elevator Use the FastCal tape hinge or Scotch
Crystal Clear Packing Tape, to join the elevator to the main body. Un-like the
Platter, only apply the hinge to the top side.
Make
sure that both elevators moves from neutral to the up position simultaneously. The
center triangle section does not move. The Stealth Platter does not require
any down elevation. Neutral flight for this airplane will be slightly up.
Step 8 - The Tail Installing the Stealth
Fins at a 60 degree angle.
Step 9 - Lead-Out Guide
You can use strip of scrap plastic or 1/16" plywood. Make a slot
into the foam board and glue it into the slot.
On any new or untested
designed model, it is a good idea to make the guide adjust adjustable. You
can do this easily by drilling addition holes. If the airplane come in at
you while you are flying, you can move the lead-out a little farther back.
Step 10 - Paint the Platter You can used
any fuel proof paint although model airplane dope is the best. If you can not
get dope, use Rustoleum brand paint will give you enough fuel proofing. Epoxy
paint is very fuel proof but don't apply too heavy a coat. You should not use
more that 2 coat on this model. One good coat should do it. If you want a smoother
job on the rudder section, apply a few coat of clear dope and sand it smooth before
spray the final color coat.
Step 11. - Control Horn & Pushrod Install all hardware.
Drill holes for the control horn first. Bolt on control horn with 1 washer on
the bottom.
Make the Pushrod from 1/16" piece of steel music wire.
Make a Z or J-bend and one end. Make an adjustment Z-bend in the middle.
Install the Control Horn and attach the pushrod to it. Make a bend 90 degree
up and attach it to the bell-crank. Position the bell-crank
in a neutral position.
Adjust the bell-crank, so the neutral position
is slightly up. This is because the Stealth Platter does not actually have
a true air-foil and require a positive incidence to fly level.
Step 12 - Bell-crank Assembly
Drill the hole
for the bell-crank and install it according to the instructions diagram.
Install lead-out assembly. Make lead-out wires from scrap .015 or .018
cable or music wire.
Step
13 - Leadout Wire
Here is an alternate method of making the leadouts from
a solid steel wire rather than using the crimp and sleeve method for stranded
steel cable.
You
can make a leadout wire from .025 music wire. Do the same on the bellcrank
end and connector end.
Step 14
- Landing Gears
Make the gear with high quality steel music wire.
Install landing gear assembly and wheels. Install the rear landing gear
8" back from the nose. Use the 440 X 1/2" bolt and number 6 washer
to fasten the gear in place.
Notice
that the washer is bend in a concave shape. This will help to secure the
gear better.
15 - Nose Gear Do not make
the lower bend for the wheel yet. This will allow you to install the nose
gear from the top.
The nose
gear is made with heavier gauge or wire. Use 5/64" or 3/32 music wire.
Step 16. - Install Engine Mount If
you can not find the aluminum T-bar for the engine mount, use 2 L-bar on each
side or construct a wood mount using 1/8" plywood for the firewall.
Plans for this mount is on the Platter Plans.
Install 1/2 oz of weight
offset on the outboard wing tip. If the outboard wing is too high or model
come in during flight, you may need to add more weight.
Install
the engine mount and do not over tighten the screws on the mount. It's only
foam-board, and over tightening can make the mount more fragile.
17 -
Your Finished
You Stealth Platter should now look like this, right?
click on picture for more detail
Step
18 - Flying
The Stealth Platter can be flown on 30' to 35' dacron string
lines. Set the control neutral with the elevator slightly up. You
may have to adjust this to determine the actual neutral position.
This airplane was designed so that a beginner can fly it off the ground.
I recommend a Cox 6 X 3 propeller. Adjust the landing gears, so that the
airplane is banked slightly to the right with the right wing down and away from
the circle. This will prevent the airplane from come in.
Step 19 - Flight Trimming
When
the airplane is in the air, watch to see if the inboard or outboard wing is dipped.
It may become necessary to adjust the tip weight so the airplane flies level.
If the airplane flies with the inboard wing down, one method is to cut down the
outboard elevator or twist them the opposite way giving the outboard more up elevator.