Hi guys,
I finally built a dolly that gives consisently awesome launches with my Clipped Wing Diamond Dust (will launch with 20-30 foot take-off roll everytime).
Parts:
1 Piece of 1/4" by 12" by 24" Poplar Plywood Micro-Lite (Birch is too heavy, Balsa is too weak) (from Hobby People)
4 Extra-light wheels (2-1/4 inch Diameter) (Part # HLFK1612) (
http://www.hobby-lobby.com/wheels.htm )-- these have to be drilled out a little to spin-freely on the axle (the axle is 4mm in diameter)
2 sets of 16" Inexpensive Wire Main Landing Gear (Part # RA1094) (
http://www.hobby-lobby.com/landinggear.htm )
8 Nylon Landing gear straps (5/32 inch) (
http://www.hobbypeople.net/gallery/567545.asp ) (Use 4 for each landing gear--they come with mounting screws)
8 Wheel collars (3/16 inch) (Hobby People) (I used 2 per wheel-- one spinning free on the inside and one locked on the outside--use Loc-Tite)-- do NOT use 5/32 inch wheel collars, they won't fit on the axles, I know this from experience!!
1 Dubro 4-40 Threaded Coupler (to go into the rear of the Dust-- between the ailerons) -- Super glue it in!
http://www.hobbypeople.net/gallery/866286.asp
1 U-shaped nail -- Hammer and Super glue it in! (Placed on longitudinal centerline, 1.25 inches from rear of plywood)--The threaded coupler from the rear of airplane goes in here
One 3/4 inch nail --Hammer and Super glue it in! (Placed on longitudinal centerline, 13 7/8 inches from rear of plywood)-- this position can vary, but near the part of the dust that lies flush with the plywood behind the fuel tank. This nail will go into the bottom of the plane.
Each landing gear had 2 wires. I placed the main wire (the one with the axle) on the inside for both the front and rear landing gear.
For the front landing gear, I placed the inner wire (closest to the center) 3 inches from the front of the plywood.
For the rear landing gear, I placed the inner wire (closest to the center) 3.5 inches from the rear of the plywood.
The 3 main things I discovered while trying out various launch dollys was:
1) Keep them light!! (Don't go heavy-duty, or the plane won't build up enough speed to take-off)
2) Make sure the wheels can spin freely and that the dolly goes somewhat straight.
3) Make sure the lite-plywood is wide enough to keep the plane from torquing off the dolly to the left. The torque of the engine will twist the plane off of a too-narrow dolly.