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

I didn't change a thing ...

I built one identical to the original poster's, including the pipe cap/carriage bolt arrangement, and it works great. When one of my flying buds saw the pipe cap/bolt arrangement, he did the same.... replacing an inferior approach he had used for the wing connection. He too is delighted with the pipe cap method. :D
 
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http://mindermanmarine.com/boatyard_frame1.htm
 
I built a set of jacks this week. The bases are 4" channel with 1"x1.5" rectangular tubing for the diagonals. The jack fits through a piece of 3" ID tubing at the top with a hole drilled and tapped for a bolt that takes up any play between the jack and the tubing. One of my first projects with the MIG welder and they turned out pretty nice.

IMG_0773.JPG
Very nice. :) They look sturdy enough to change the wheels on an A380!
 
You guys are making it harder than it needs to be.

Grab a 12 point socket that is nicely bigger then the jack ram (so it doesn't bind up).
Put some HDPE tape on a big washer (to protect the wing paint).
Put a bolt through the socket and washer and into the tie-down hole and snug up.
Put the ram of the jack into the socket.
Jack it up!
Won't slip off. Ever. If it does, you seriously messed something up!
No mods to the jack ram necessary
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I use something similar to what fl-mike suggests. However......

OK, So I need opinions on jacking like in the photos.

Quick and easy. Flat tire repair on a friend's RV-8. He taxied off runway with the flat. The line guys came out. Jacked the plane using the foam block. Said they use it all the time. Never a problem.

Seems like the ideal solution and allows for "creep" on a tail dragger. Seems like it would work great for general maintenance, bearings, tires, wheel pants, etc.

What can go wrong? Just asking because I don't know.

Rule out "foam block can crush or break" because it ain't happening. Very tuff stuff.


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Got mine done!

Harbor Freight's cylinder jacks are now red. I got my platform legs cut and welded, and I had the support legs top attach bracket plasma cut. I am very pleased with the final product. Getting the steel platform legs welded and the top bracket made, ended up costing a little more but it still came in at about $150. much cheaper than ordering one online. I only jack one side at a time so one is all I need.

IMG_00132.jpg
 
Bob, I like your design. Do you have any close-up shots of the top bracket?

Is anyone having any trouble with the length of the jack under a RV-7 wing. When I had my flat recently, I took a quick measurement of the space between the bottom of the wing at the tie-down point, and the ground and at best it was 24". But it looks like everyone else is having no trouble even though the jack is 23" or so itself???
 
I'll try to get you a picture next time I'm at the hangar. It worked out great!
Just found this one, if that helps:
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Here are mine, built sometime ago . They were very expensive but they come with a mig welder. :) I have since been learning to use it. Larry

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jack stands

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?
 
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.
 
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.
 
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. :):)
 
not that it matters for jacking load analysis

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
 
RV 10 jack at the wing

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...

IMG_4049.jpg
[/QUOTE]
 
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.
 
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.
 
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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 :)
 
RV-10 Jack Points

I wasn't happy with an unsupported bolt as a jackpoint, so I added a shim riveted to the inside of the skin. The shim contacts the bottom of the threaded T section that attaches to the spar. When the jackpoint is screwed into the wing in place of the tie-down ring, it's snugged up against the skin, shim and wing structure, so any bending load on the threaded portion is virtually eliminated.

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The jackpoint itself is made of a bolt with a cone attached with a set screw and tapered to a 90 degree profile. It sits into a 100 degree countersink in the top of the Harbor Freight bottle jack, so there's some tolerance for wing dihedral. The arrangement works well and is quite stable. By the way, there's plenty of extension on the Harbor Freight jacks to comfortably lift a -10 in a level flight attitude.

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