Putting my money where my mouth is.

Well, since I opened my big mouth and suggested it, here’s my unofficial tether car design.  It’s my day off, so I went ahead and started.  Digging in my plywood supplies yielded up a 1/8”x6”x12” piece of ply.  I printed off a picture sort of like what I want and cut it out.  Then I taped it onto the 1/8” ply that I had marked the wheel locations on.  That went over to the scroll saw and the profile got cut out.  My camera is pretty lousy at close up shots, so if anything looks crooked or bent, it’s the crappy lens.





Putting some wheels in place for some perspective.




Once I had the general shape, I drew a base for the car out of more of the 1/8” ply and marked the slots for alignment tabs.  Again back to the scroll saw.





Then a quick test fit of the plate to make sure everything was good.




Then I glued the pieces together with a triangle to ensure alignment.





Next I cut and glued in place an axle bearing tube.




With the axle cut to length and wheels mounted.




Finally for the day, I drilled mounting holes for the drive gear.  I decided first that I would use wheel drive instead of prop drive.  For ease, I went with direct drive.  A tanked Bee didn’t appeal to me, so I figured I’d use the product engine that I used for the Hobbico 1/2A fuel test.  I’ll make up an appropriate tank tomorrow.  To make things symmetrical, I used another product case for the other side.  Besides, if the performance isn’t good I might want to try making a twin engine tether car by putting a piston and cylinder into the idle case.







After assembling everything, I think the wheels I used are just too small.  I picked smaller wheels because I didn’t want to overload the engine when it first starts its run.  Maybe after the first runs I’ll try larger wheels.  Also, I think 12 inches is just a little too long.  I might chop off 1” from the front and another from the back, then squish it down tomorrow.  I think this model is going to be my most expensive 1/2A model to date.  I bought wheels, collars, 5/32" rod, tubing, and landing gear hold-downs today.

The Foot In Mouth Mark