a great way to spend 45 dollars... put together a wing jack stand

[Kofficer]

I know this is older thread, but my concerns is that the question was never answered about whether or not the threaded tie down point is truly strong enough to push up 500lb. Also, if you do use this point, wouldn't it be better to cut the bolt down to where you could screw the cap all the way up to the wing to not be pushing on just the threads? Could possibley put something between the 1" pipe cap and wing to keep it from scarring up the undersurface?

[tmbg]

Originally Posted by Kofficer

I know this is older thread, but my concerns is that the question was never answered about whether or not the threaded tie down point is truly strong enough to push up 500lb. Also, if you do use this point, wouldn't it be better to cut the bolt down to where you could screw the cap all the way up to the wing to not be pushing on just the threads? Could possibley put something between the 1" pipe cap and wing to keep it from scarring up the undersurface?

WAY strong enough. If I remember correctly, those are AN6 size holes, AN6 has a tensile strength of at least 14,000lb. The stripping strength of the aluminum tiedown will exceed the tensile strength as long as you have 3 diameters thread engagement, which is ~1". The tiedown block in the wing is bolted to the spar with 4 AN3 bolts, which are good for 2100lb EACH in single shear. Remember, the tiedowns are designed to prevent the airplane from flying in a high wind. If it's flying, it's lifting the entire weight of the aircraft. The tiedowns easily handle that.

[maniago]

Originally Posted by tmbg

If it's flying, it's lifting the entire weight of the aircraft.

Point of order: If a wind is lifting the aircraft, its lifting at least the aircraft weight, but far more likely to be more as the aircraft is accelerating upwards - ie its in G load. How much? Noone really will ever know except the tie downs.

But the rest of your answer is on point.

[rightrudder]

Originally Posted by tmbg

WAY strong enough. If I remember correctly, those are AN6 size holes, AN6 has a tensile strength of at least 14,000lb. The stripping strength of the aluminum tiedown will exceed the tensile strength as long as you have 3 diameters thread engagement, which is ~1". The tiedown block in the wing is bolted to the spar with 4 AN3 bolts, which are good for 2100lb EACH in single shear. Remember, the tiedowns are designed to prevent the airplane from flying in a high wind. If it's flying, it's lifting the entire weight of the aircraft. The tiedowns easily handle that.

Nice analysis.

[Bill Boyd]

but at the moment a gust lifts the plane off the tarmac, the load on the tie-downs is ZERO, unless you're pre-loading with a ratcheting tie-down where most of us just use a snug taut-line hitch in a rope.

Correct me if I'm wrong.

Good to know the tie-downs are structurally good-to-go for use as jack-points, though.

-Stormy

[jor.ezq]

My doubt is how long is the jack pist?n in orden to lift the -10
, in the pic, it seems about a feet out and the plane is still on the ground.
Can you see it ?

QUOTE=frazitl;624328]made almost exactly the same as Stephens about 6 years ago for our Mooney.
To solve the problem of attaching the support struts at the top, I found a
ring in the electrical isle at Home Depot with an ID big enough to just
swallow the jack body. I think it even had four flats around the
circumference to attach the strut tops with screws. Anyway, they work
great. I countersunk the top of the jack ram to deepen the hole, and just
use two cut off bolts in the tie down holes to provide secure jack points.

Only improvement I might make is to buy some lock rings available from industrial supply houses like McFaddin-Dale. Probably safer if you ever have to leave the plane on the jacks overnight...

[/quote]

[Snowflake]

Originally Posted by jor.ezq

My doubt is how long is the jack pist?n in orden to lift the -10, in the pic, it seems about a feet out and the plane is still on the ground.
Can you see it ?

Note that the nosewheel is off the ground as well. If the nosewheel were lowered the mains would come off the ground with the jacks that far extended.

[JonJay]

I always jack the plane in flight attitude. This keeps side loading off the jack points. As Rob noted, this should raise the mains on a nosewheel RV.
The only jack point failure I am aware of was use of the wrong type of bolt in the jack point and then a gross side load causing the bolts to bend and shear.
This setup is not right.

[vernon smith]

Originally Posted by JonJay

I always jack the plane in flight attitude. This keeps side loading off the jack points. As Rob noted, this should raise the mains on a nosewheel RV.
The only jack point failure I am aware of was use of the wrong type of bolt in the jack point and then a gross side load causing the bolts to bend and shear.
This setup is not right.

They put wheels (with castering) under car floor jacks for a reason

[Plummit]

Originally Posted by vernon smith

They put wheels (with castering) under car floor jacks for a reason

Yeah but when was the last time you saw an aircraft jack with castering wheels....

-Marc