Wing Jacks

[isaacpr7]

Any effect on the cylinder due to welding?

What is on the other side of the heated surface?

Just wondering, I have no welding experience or skill beyond simple spot welds in an orthodontist office.

Best regards,

-a-

It's better to show you rather than try to explain. Check the link below for an Xray of how the jack works:

https://www.google.com/url?sa=t&source=web&rct=j&ei=ppKMVJbdK4aSyQTVmYDoCw&url=http://m.youtube.com/watch%3Fv%3D5jtLpt0u8vw&ved=0CBwQtwIwAA&usg=AFQjCNFpaHv26s16NHy9kyJWR0XZvOA59g&sig2=4EqXZrL6UMHRtiAE3dj_3Q

[isaacpr7]

The outer chamber holds the fluid while the jack is down. As you pump, fluid (which is non compressible) moves from the outer to the inner chamber that holds the shaft. When you release the valve, fluid goes back to the outer chamber allowing the shaft to come back down.

[carusoam]

That's a great explanation!

Thanks for posting it.

Best regards,

-a-

[isaacpr7]

When we designed the connection between the jack and the jack point we were extremely concerned with the possibility that jack point could slip off of the jack. It's difficult to tell from the photos, but there's a socket and ball connection between the jack point and the top of the hydraulic ram. In addition, there's a brass fitting sitting on top of the ram that would make it even more difficult for the jack point to slip off of the jack.

If the third point (tail weight or an engine hoist) fails, I would expect any wing jack to go through the wing as did in that photo. Wing jacks are only designed to lift the plane- balancing the plane on the jacks is another matter altogether.

Smccray,

I'm done building my jacks; however, I still have not build the connection between the jack and the airframe jack point. Do you have any more pics and a list of materials you would be able to share?

[isaacpr7]

When we designed the connection between the jack and the jack point we were extremely concerned with the possibility that jack point could slip off of the jack. It's difficult to tell from the photos, but there's a socket and ball connection between the jack point and the top of the hydraulic ram. In addition, there's a brass fitting sitting on top of the ram that would make it even more difficult for the jack point to slip off of the jack.

If the third point (tail weight or an engine hoist) fails, I would expect any wing jack to go through the wing as did in that photo. Wing jacks are only designed to lift the plane- balancing the plane on the jacks is another matter altogether.

Smccray,

I'm done building my jacks; however, I still have not build the connection between the jack and the airframe jack point. Do you have any more pics and a list of materials you would be able to share?

[isaacpr7]

I found this solution for the jack point. It looks pretty sturdy. I think I might give this one a try.

http://www.vansairforce.com/community/showthread.php?t=82111

What do you guys think about that design? Do you think it will have any issues?

[Guest]

I would not trust raising my airplane on a cheap hardware store bolt screwed into the wing as shown in the picture.

Clarence

[N601RX]

I cut the jack shaft off just below the cross hole and then made a large diameter deep countersink into the top of the jack shaft. I made the countersink as deep as I could so that when the lasar jack point was placed in it there would be just a small amount of clearance between the top of the jack shaft and the wing skin.

I'm pretty sure the jack is going to be too hight to go under the wing if you do it the way the RV guy did his. The RV is also a much lighter plane.

[Andy95W]

I would not trust raising my airplane on a cheap hardware store bolt screwed into the wing as shown in the picture.

Clarence

Agreed, and a little scary to even look at. That is a lot of weight to suspend from merely the THREADS of a 1/4-20 bolt.

[DaV8or]

I found this solution for the jack point. It looks pretty sturdy. I think I might give this one a try.

http://www.vansairforce.com/community/showthread.php?t=82111

What do you guys think about that design? Do you think it will have any issues?

 

No f'in way I would use that. There is frugal and there is stupid. That one looks stupid too me. YMMV.

[DaV8or]

Agreed, and a little scary to even look at. That is a lot of weight to suspend from merely the THREADS of a 1/4-20 bolt.

 

In all fairness, it is bigger than 1/4-20. It think it is either 3/16-18, or maybe even 1/2-13. I can't really tell. Either way, I would not use that rig on a Mooney.

[isaacpr7]

This one also caught my attention and seems sturdy.

http://mail.lancair.net:81/lists/lml/Message/68751-02-B/image001.jpg

http://www.trade-a-plane.com/search/show_image?listing_id=2043275&width=140

The only bad thing is that they cost 100 bucks a pop. Ouch!

Or these from spruce:

http://www.aircraftspruce.com/catalog/topages/jackpointsmooney.php?clickkey=9555

[carusoam]

Or known Mooney parts from Lasar...

[isaacpr7]

Or known Mooney parts from Lasar...

I called LASAR this morning and left a message. I like the fact that it comes in an installation that you could leave in and includes tie down rings. Hopefully it's not too expensive.

[Yetti]

Since I need to change tires soon, I was thinking about this, I would like to have some sort of positive mechanical locking between the jack and the plane.  This morning I started with a piece of steel with a hole big enough to fit over the head of the jack.  You could cross drill the hole to run a pin though the hole on the top of the jack.  Tap and run a cap bolt through to screw into the plane.  Cut a piece of rubber mat to protect the finish.

 

But I realized that there should be some swivel between the plane and the jack.   So currently looking at Impact swivel socket cross drilled to pin a bolt for the plane and then drilled out for the top of the jack that can still be cross drilled to pin the swivel socket to the jack.

[carusoam]

Isaac,

I was looking on the Lasar web site...

But couldn't find them...

They used to be called tie downs and jack points.

They are on the west coast, so it may take a few hours before anyone is there...

The jack points are threaded to keep them in place.

Best regards,

-a-

[mooniac15u]

For some reason they are listed with the wheel covers. http://www.lasar.com/mod-details.asp?id=27

[carusoam]

Web site error....!

-a-

[Bob_Belville]

Commercial jacks are not all that expensive. MooneySpace has a thread or two with jacks sticking through wings. Penny wise, dollar foolish? I also have the lasar jack point/tie down combos. I think that's the way to go. 

[Yetti]

Pennywise or pound foolish would depend on if they were commercial jacks through the wings. Which it appears they are.  Fixing the interface point is how to prevent a jack through the wing.

[Bob_Belville]

Pennywise or pound foolish would depend on if they were commercial jacks through the wings. Which it appears they are.  Fixing the interface point is how to prevent a jack through the wing.

Just saying there could be engineering details a Rube Goldberg designed jack might miss. Baling wire and duct tape didn't go into space. 

[DonMuncy]

I agree Bob. Anyone building their own jacks should carefully consider the design and construction techniques.

[Yetti]

I thought they fixed the Apollo 13 makeshift air filtration system with duct tape.

[RobertGary1]

I thought they fixed the Apollo 13 makeshift air filtration system with duct tape.

 

With a room full of super smart engineers designing it in real time. 

 

-Robert

[mooniac15u]

I agree Bob. Anyone building their own jacks should carefully consider the design and construction techniques.

 

You mean like the fact that all the commercial ones have 3 legs?