Frank Whiteley
October 7th 08, 02:49 PM
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
> 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