wrote:
Does anyone have a
source for this type of screw jack in the USA? I have seen similar
jacks used in some older European cars. My web searches on "screw jack"
only return very large capacity equipment.

http://www.cobratrailer.de/english/index.html
The illustration opposite shows different versions of lift ramps for
the fuselage: ...a version with screw jacks, especially useful for
gliders with low fuselage..

Mark,

In my opinion, the screw jack is definitely the best design. A
scissors jack suffers from the fact that the lift vector is at a
miniumum when fully compressed - ie. just when we need it most in
gliding. Hydraulic jacks are always requiring maintenance and run the
risk of a "rapid decompression" if you accidentally flip the valve,
leading to a nasty fuselage tip over. The screw jack provides
linear lifting, so the amount of lifting is always directly
proportional to the amount of turning you do on the handle.

I had the screw jack from Anschau Komet, and it was great. I think you
can find the parts you need if you search on "acme threaded jack"
instead of just "screw jack". McMaster Carr sells a line of "light
duty" Acme Threaded Jacks that might be just the ticket. You need a
mechanism to drive both worm gears uniformly, so there is some
engineering involved. It may just be easier to spend the money and buy
one from Cobra or Komet.

http://www.mcmaster-carr.com and type in Acme Screw Jack in the search
window.

Regards,

Erik Mann
LS8-18 (P3)