May you explain to me why precisely...
Sorry - can't.
That's from my proposed USHPA Aerotowing Guidelines document. In compiling some of it I used material from previous versions and whatever else relevant I could get my hands on. If it was something about which I had no expertise but with which I could see nothing obviously wrong I included it. That's the case with those dolly specifications. And it appears that whoever wrote it put some thought into the issues.
What do you think about the position of the basetube...
My first thought was that I liked it because it would be more pitch stable and the only downsides would be storage and transportation issues. I didn't even think about yaw stability until I read your sentence. So I'd say your assessment is gonna be better than mine.
Yeah, like just about everything else we do in aviation design it's a tradeoff - better pitch stability, worse yaw stability.
If I were going to build a conventional cart I would probably just copy the specifications of the ones I used at Ridgely because it seems to be a good, efficient design and they've each individually had tens of thousands of launches without any problems.
However, if the design of the one in your photo doesn't exhibit any yaw stability problems in actual use - fine. If there's a nasty surprise on a runway somewhere someday it could save somebody a broken neck. And - as long as that somebody isn't Davis or Rooney - that would probably be a good thing.
The T-dolly...
See above.
Also...
- Since the basetube brackets aren't supported at the aft end, the farther aft you position the basetube the more torque/stress you're exerting on the (welded) bracket supports.
- I'm not sure I like the basetube brackets design. Seems like the cutout on the top is backwards and would make the liftoff rather sticky.
But again, if this design is working fine in the field... fine.
P.S.
Five years ago I intended to build a T-dolly and purchased the plans from John Pop but never got beyond the stage of purchasing wheels and a few materials.
The photos were good but text was such garbage that it took me a couple of days to decipher it and edit it into something intelligible.
I think it's probably a good design and I agree that setting a glider on a conventional dolly is a royal pain in the ass but I've also heard that it's not that hard to damage oneself walking into the dolly's keel if one isn't careful.
Emergency Procedures
