How to suspend a glider?

On Oct 7, 6:49*am, Frank Whiteley wrote:
On Oct 7, 5:49*am, "Paul Remde" wrote:



Hi Don,

Great idea! *I can't wait to see it! *I'd be glad to help.

Take a look at how the ASK-21 is hung at Stanton Airport. *My guess is that
the system used is over-designed by a factor of 10.

Without doing any calculations, I would recommend seat belt material rather
than canvas. *2 to 4 straps should do the job easily - I think. *They could
meet at the top of the glider where a cable could attach. *You should be
able to get strength ratings for it the material. You'd want to use a safety
factor of 4 or so (only use 1/4 the of the weight they can handle). *I'm not
giving you engineering advice, just my quick thoughts. *I imagine that
putting knots into the seat belts would reduce their strength dramatically.

Paul Remde

"Pete Smith" wrote in message

...

It is very common in continental Europe to suspend gliders from the hangar
roof to make full use of the space available. I'm sure someone who does
that will be along soon.

I have seen a Nimbus 3/4 strung up at a Swiss club.

At 06:28 07 October 2008, wrote:
Hi all,
Has anyone out there ever suspended a glider in the air without
resorting to the conventional method of airflow over the wings? I have
an opportunity to hang both of my Grob 103's in two malls over the
holiday season. I am pushing for having a Santa in the back and a
Rudolf leaning forward in the front, scarf trailing. Both canopies
will be off. I will have a Glider Ride Gift Certificate booth [not
quite directly] underneath. Some of you may have seen my Mall
Experiment article in the June 2008 issue of Soaring. Well, I'm
experimenting some more!
My first thought, unencumbered by either engineering training or good
advice, is to fabricate a heavy duty, white canvas sling, maybe 2 feet
wide, that would go where the fuselage dolly goes, in front of the
wings and as far aft as possible. The CG hook mechanism could be used
to attach to it also to protect against slippage. The sling would be
sewn proffessionally, providing a pair of rip-free, foolproof,
attachment points on each side. The remaining 50 lbs on the tail could
be handled with a wire running from this central sling support cable
45 degrees down to the horizontal stab attachment bolt at the top of
the verticle stab. The wings could have wires running from the wing
tip skid/tie downs to this central sling support cable at about 45
degrees also.
Thoughts?
Clearly the mall engineers and their insurance underwriters are going
to have the last word, but if any of you have advice/experience/
thoughts, I'd sure appreciate hearing from you. Oh yeah, the 103
weighs in at 850 lbs.
Thanks in advance,
Don Ingraham
http://www.crosscountrysoaring.com

Working load is normally 1/6 of breaking strength (except for winch
ropes);^).

Frank Whiteley

You will definitely need a design and sign-off from a Professional
Engineer (Civil / Structural). Not only for the lifting hardware, but
for the capacity of the attachment point above. I have a number of
colleagues in MN that may be able to help or direct you to another
professional that can help. Please email me directly if you would like
some contacts.

Best Regards,
Craig Funston, P.E. , S.E.