Random thoughts from an old guy:

A really-really good trailer is a joy. Cobra's are just good.

Tubes are inherently stiffer and stronger - if they're well engineered.

Most problems with tubes are related to a too-small cross section. If the tube is tilted to roll the fuselage off, the wing trailing edges hits the roof when rolled off. Raise the roof - eliminate that problem. Make it wider and get better access.

One-man riggers:

They're great but could be better with some trailer mods. Most problems are related to stumbling past the dolly carrying the wing tip and then sashaying out past the fin and back to get the wing aligned with the fuselage - sometime tricky in wind, on rough ground or in tight quarters.

Possibilities: (No lifting whatsoever.)

(1) Since most new gliders these days have detachable tips or winglets, build a wingtip dolly resembling a tail dolly that attaches to the tip using the existing fittings so as to eliminate carrying the tip weight as the wing is rolled off the trailer. Tip dolly should be jack-able with a castering wheel. Attach-jack-roll out.

(2) Make wing root dolly in trailer swing like a gate so the wing with tip dolly can be swung out roughly 45 degrees to the fuselage before fitting the one-man rigger. Then, remove tip dolly, pick up root and walk directly to fuselage as wing aligns rotating about the one-man rigger as you go. Advantage, one-man rigger rolls only about a meter so far less smooth surfaced space is needed. Safer in wind.

Swaying trailer:

Single-axle Cobra trailer swayed even with hulking SUV towing it and hitch loaded with more than 10% of weight. Tried inflating trailer tires to max allowed - towed dead straight afterward.

Tilting trailer:

Running front-to-back again and again to get the tilt just right is a pain in the feet. The boat guys use electric tongue jacks with the up-down switch at the back of the trailer.




On Wednesday, May 22, 2013 2:08:11 PM UTC-6, Bob Whelan wrote:
On 5/22/2013 1:29 PM, Steve Leonard wrote:

On Wednesday, May 22, 2013 1:35:24 AM UTC-5, GC wrote:

Aberdeen Angus, I think - or maybe Poll Hereford. Is that the trailer

where the fuselage and wings go in from the hitch end, not the number

plate end? Or is it the one with the door at the hitch end where the

wigtips go in first on a strop which runs in a track on the roof - until

it jams halfway in and you can't get past the wing and fuselage to

disgorge it (or whatever you need to do with jammed wheels in tracks).

GC



Ugh. Yes, the early Schleicher trailer has you hang the tip in a strap

that runs in a track along the roof, tip went in first, and you carried the

root out. Great fun with an AS-W12. Not as bad with a 15. Some US Made

Sailplane Associates trailers do this, too. But, a lot of them load

through the number plate end. Early Schleicher loaded over the hitch.

Then, there were the ones that had the hitch that got un-pinned from one

side and swung out of the way for loading from the hitch end.



Thank goodness we have evolved as we have. Those old trailers were a royal

pain in the Arse!





Haw! They were a PITA even "way back when (I was young and stupid)!!!" They

haven't improved with age - theirs OR mine.



Sailplane trailer evolution is a classic case of darwinism in

action...combined with intelligent design...uh oh, I may be in trouble with

some portions of society here.



Bob - I'll be leaving now, my work here is done - W.



P.S. For the life of me, I've NEVER been able to imagine even a

half-baked-rationale why anyone would have EVER designed a glider trailer to

load/unload over the tongue. I owned one once. I let the neighbor kids destroy

it with sledgehammers, then burned the resulting splinters. Both events were

immensely soul-satisfying for all concerned.