Craig[_2_]
October 7th 08, 09:23 PM
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.
> 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.