Take-off dollys
05-21-2007, 10:47 PM
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Take-off dollys
Has anyone in this forum designed / used a successful take-off dolly for their aircraft?
At times there are some models I'd like to try WITHOUT an undercarriage - hand launching will be ok for some models but those with higher wing loadings can cause problems. Enough forward speed & release at the correct angle of attack are 2 of the issues for hand launching.
I would guess that with take-off dollys there would also be some issues to overcome - wheel layout (what's best? tricycle, 4 wheels etc) steering ("bump" steering would be an issue on its own), premature rise from the dolly & maybe even not releasing at all from the dolly.
I've read many accounts from WWII about the take off dolly used by the Germans for the ME163 - their system was problematic to say the least.
All info - including success & failures - will be appreciated
At times there are some models I'd like to try WITHOUT an undercarriage - hand launching will be ok for some models but those with higher wing loadings can cause problems. Enough forward speed & release at the correct angle of attack are 2 of the issues for hand launching.
I would guess that with take-off dollys there would also be some issues to overcome - wheel layout (what's best? tricycle, 4 wheels etc) steering ("bump" steering would be an issue on its own), premature rise from the dolly & maybe even not releasing at all from the dolly.
I've read many accounts from WWII about the take off dolly used by the Germans for the ME163 - their system was problematic to say the least.
All info - including success & failures - will be appreciated
05-22-2007, 12:13 AM
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RE: Take-off dollys
I don't have any pictures of them but I have made a couple of them.
One was for a SiG Wonder (flying wing) and consisted of two flat beams (1/2" x 1/2" pine) with two 4" long dowels upright in the front. It had two wheels on the front and 1 fixed wheel at the back. It works well. As the plane gets enough speed up to fly (not very far in the case of the Wonder) it just lifts off from the dolly.
The other one I made is for larger planes (40 sized speed planes). It's similar but it consists of a "Vee" shaped former at the front and a tricycle undercarriage. it carries it's own battery pack, Rx and Servo and the nosewheel is steerable.
These were all made from scrap items I had laying around. Wheels from deceased planes, Rx was an old one that I don't trust in a plane anymore, Servo from a deceased plane, battery pack was an old one that I removed when doing my annual major maintenance.
I've also seen these things done with bushings in the plane (Taildragger configuration) and pins (instead of bolts or screws) on an undercarriage - in that case, the undercarriage simply fell away as the plane took off.
You don't want to leave too much stuff on the runway after takeoff though - the other fliers sometimes get a little upset.
One was for a SiG Wonder (flying wing) and consisted of two flat beams (1/2" x 1/2" pine) with two 4" long dowels upright in the front. It had two wheels on the front and 1 fixed wheel at the back. It works well. As the plane gets enough speed up to fly (not very far in the case of the Wonder) it just lifts off from the dolly.
The other one I made is for larger planes (40 sized speed planes). It's similar but it consists of a "Vee" shaped former at the front and a tricycle undercarriage. it carries it's own battery pack, Rx and Servo and the nosewheel is steerable.
These were all made from scrap items I had laying around. Wheels from deceased planes, Rx was an old one that I don't trust in a plane anymore, Servo from a deceased plane, battery pack was an old one that I removed when doing my annual major maintenance.
I've also seen these things done with bushings in the plane (Taildragger configuration) and pins (instead of bolts or screws) on an undercarriage - in that case, the undercarriage simply fell away as the plane took off.
You don't want to leave too much stuff on the runway after takeoff though - the other fliers sometimes get a little upset.
