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TAIL ASSEMBLY
The elevators and rudder are both built in one piece. The leading edge
is constructed from 2 strips of 1/32 x 3/32 soft balsa and
formed together with a strip of 1/32 x 3/32 basswood on the outside. I
like white glue to glue the three strips. interior wood is 1/16 x 3/32. Cover both sides of frame.
FUSELAGE
Build each side from 1/16 square hard balsa or 3/32 medium for the
longerons. The length of the longeron is 18 inches with 4 bays of 1 1/2
inches and 6 bays of 2 inches. The fuselage is shown short on the plan to
accommodate an 11 x 17 sheet. The first bay is filled with sheet balsa as
is the last to accommodate the motor peg. Form the box using a square
former at the nose, landing gear and at 6 inches station. let dry them add
remaining cross pieces. You may reduce the cross sections from 1
inch to 3/4 as you move to the rear from station 12 inches if you like,
otherwise keep it square. Once the fuselage is dry and has been solidified
assemble the tail unit. The nose is built up. I like to laminate a piece
of wood (strawberry boxes are excellent sources) to one or two pieces of
1/16 sheet. Once this is dry cut out hole for thust
button. Install your motor (1/4 inch wide at 150% fuselage length is a
good starting point). Torque it up 350 turns and see
how much your fuselage twists. If it twists, ADD
DIAGONAL BRACING ON TOP/ BOTTOM AND SIDES AS NECESSARY.
LANDING GEAR ASSEMBLY
Bend wire as per Charles H Grant's original plan (click
here for the original plan) and then mount it on the balsa strip that runs from the nose to the landing gear station. Add
additional hard balsa top and bottom of this strip
to provide strong stable mount for gear. Assemble to
bottom of fuselage.
WINGS
The wings are built up except where they join at the center.
Leading edge is 1/8 x 3/32 hard, Trailing Edge is 1/16 x 18
or 3/16 medium. Ribs are 1/20 shaved to fit over a
1/16 x 1/8 spar which runs the entire span. Rbs at 2
inches and 10 inches are full ribs while those at 4, 6, 8, are shaved.
Assemble and let dry. The center section is flat to remain true to CH
Grant's original design. The wing butt-joint is 1/8 square as is the rib
at 1/2 inch ( this mates to the fuselage longerons)
a 1/16 piece runs from the leading edge to the first wing
rib at the max height then from there to the training edge. Set the
Dihedral angle of 3 inches per panel and let dry. At a flat wood plate
between the 2 ribs at 1/2 inch to form a stable platform which rests
on the bottom of the fuselage.
COVERING
Bright colours please as your plane can and will climb trees and hide
in long grass.
FLIGHT
ELEVATOR DECLAGE
I mounted the main spar of the elevator to the back of the fuselage so that I could shim the elevator at the LE if I needed
negative declage on the tailplane.
WING ANGLE OF ATTACK
I mounted the wing with a rubber band to permit the wing to be adjusted
forward backward and at angle of attack by shimming the TE as required.
My results were flat tail (0 degrees) and 1/8 shim at TE worked good.
FLIGHT
YOU"LL NEED A FOOTBALL FIELD to fly this plane or say goodby to
it!!!!! It will fly in a breeze although still air is better. Plane will
circle nicely and can fly tail heavy with good
recovery (that's why wing should be adjustable).
Flights of 35 to 40 seconds are expected on 1200 to 1500 turns.
Flight
times 37, 37, 37, 55 and 32 seconds (tree strike on
last time).
Pics on my webshots by end of month
(August 2001).
JIM
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Cloud
Tramp II Construction Notes
