Dirt Simple Aircraft Jack

[Tony Spicer]

Seeing an aircraft on wing jacks gives me the willies. This doesn't:

http://picasaweb.google.com/tonyboyt...leAircraftJack

Tony

[videobobk]

Looks simple and safe enough. Should work well. Only thing I wonder about is how you get those 1/4" bolts through 7/32" holes? Must take a big hammer...

Bob Kelly

[Tony Spicer]

Good catch! Every now and then Picasa turns a 9 into a 7.

Tony

[Captain Avgas]

I reckon it would take all the powdercoat off the landing gear leading to corrosion. And if it slips or spins just a little...it will rip out your brake lines. Not a good design in my opinion.

[Andy Hill]

I'm afraid my instrinct is as above... You either need to "grip" the leg very tightly, and/or a slip is v bad news The slightest indent made into the gear leg is the start of a failure mode (as above, even just through the paint allowing a corrosion start point).

There is a vertical up force from the jack, turned through ~45 degreees. Apart from the above issue, this now pushes the leg "outboard", which might cause the jack to topple over?

We have used a scissor car jack with an AL adaptor under the base of the leg / axle, and has fittings onto the fairing bracket to try and avoid a slip. It is not ideal, and again, as you "lift" the gear leg moves outboard, so the initial positioning of thge jack needs to make some allowance. However, at least the vertical jack force is applied vertically to the leg/axle assembly, and over a much larger area.

Just an opinion which may have missed something in the design...

Andy & Ellie Hill
RV-8 G-HILZ

[Tony Spicer]

1. The tire moves up, not out. Less than 2" movement on the jack and the tire will come off.

2. There's flap tape on the gear leg. The paint isn't marred.

3. If the clamp is installed so it makes full contact with the notch on the jack pad, and the jack positioned under the notch, there is no twisting moment possible.

4. The tensile strength of two 1/4" grade 8 bolts is certainly up to more than supporting the weight on the jack, whatever the moment on the pad.

5. It works just fine!

Tony

[RudiGreyling]

Tony I like it!!

[AllanC]

Tony,

Good concept, only thing I would change would be to make the 'hole' in the block circular instead of 'square'. This allows greater clamping force and less chance of an indentation into the gear leg. As the gear leg tapers and gets larger in diameter as you go up, once the 'clamp' is tight, it is unlikely to move up. To resist turning around the leg, the more clamping area the better, so a circular hole is better. As the clamp is aluminum, I don't think it could indent or even scratch the gear leg anyway....FWIW....

[Yukon]

Originally Posted by Captain Avgas

I reckon it would take all the powdercoat off the landing gear leading to corrosion. And if it slips or spins just a little...it will rip out your brake lines. Not a good design in my opinion.

Van's sells a similar device, so how bad can it be????

[Tony Spicer]

Originally Posted by Yukon

Van's sells a similar device, so how bad can it be????

Dang! Well at least I saved $19+$4+$4.

http://www.vansaircraft.com/cgi-bin/...duct=jackpoint

Tony