Problem for bored engineer types

[raytork]

You had mentioned earlier that you were considering some kind of support to the ground. This brings up the issue of lateral stability. A pickup is sprung and you are proposing to add a long bar and cables terminated fairly close together. The addition of the new hung weight from the back of the pickup introduces the risk of side to side oscillation of the structure when there is any disturbance.

 

[WHY]

Hey Chuter

A good source of "Strong" light weight tubing is drive shaft material, don't know what it is as far as alloy but it is good stuff. You will probably need two pieces per leg

Tony

 

[chuter]

raytork,

I think I know what you're saying, and hopefully there would be someone close by to steady the gyro while it's hanging. I sure wouldn't hang it in much wind.

Toni,

Thanks, I hadn't thought of that.

 

[chuter]

zeeoo,

I would like one of those; I think they'd be better overall. I was just trying to keep it as simple to make and cheap as possible, and it seems like a single boom with 2 cables would be the best way to meet that criteria.

 

[Victor Duarte]

zeeoo,

I would like one of those; I think they'd be better overall. I was just trying to keep it as simple to make and cheap as possible, and it seems like a single boom with 2 cables would be the best way to meet that criteria.

That's right Michael, if simplicity and cost are the goal, then you're on the good track.
Thank you

 

[Dean_Dolph]

Michael, you may understand what raytork is saying but I'm not clear.

I think he is saying, that along with clearance at the top, that the side of the gyro might hit the boom when the gyro is raised. If he isn't saying that then I would think that it this would have to be taken into consideration. The wider the gyro the more likely the problem. Flattening the boom angle where the top of the lifting cable is more than 4' from the base would help.

The lateral stability that raytork mentions could be mitigated by a wide boom base on the ground as you have mentioned. I don't know the nomenclature but something similar to the outriggers that back hoes use.

You need to know that there are some gyros that, when lifted, hang down so much that there can be a problem getting the nose wheel off the ground. During the double hang part of a Cg determination hang test at Bensen Days '07, C. Beaty's gyro hung at such an angle that Chuck was almost standing in the rudder pedals. See the attached picture. He was swift enough to know that the seat belt needed to be fastened!

A SportCopter couldn't be lifted high enough to get the nose wheel off the ground. But I can't remember if this was during the teeter bolt hang test or during the double hang test. So be prepared to short couple between the teeter bolt and the lifting cable so you can use all the lift height. If you do Cg determination hang tests then you need to be aware that there may be a problem selecting the hang point for the 2nd part of the test. A well thought out bridle would help. They had to improvise at Bensen Days.

 

[chuter]

I think I'm on the same page with you Dean. It probably won't accomodate a side x side gyro, but it seems most gyros are pretty narrow at the top.

I'm not really counting on it working for the double hang test; I doubt that it could raise the gyro high enough. But it should be good for the basic hang test of most gyros (I think).

I just tried making B = 5 ft in Udi's spreadsheet, this would give it more side clearance, and the forces may still be doable.

Hmmm...........I may do that.

(I notice Chuck has a beverage in his hand; probably caused it to be more nose down)

 

[Udi]

You had mentioned earlier that you were considering some kind of support to the ground. This brings up the issue of lateral stability. A pickup is sprung and you are proposing to add a long bar and cables terminated fairly close together. The addition of the new hung weight from the back of the pickup introduces the risk of side to side oscillation of the structure when there is any disturbance.

A simple solution to that may be to support both sides of the back of the truck instead of supporting at the hitch. All drivable cranes have at least 4 external supports, so they don't have to rely on the truck suspension.

Udi

 

[GyroRon]

The easiest solution is to find a good tall oak tree and park the gyro under one of the branches and lift it with a chainfall.......................

 

[ezeddie]

GOD, I love Oak Trees, with or without yellow ribbons........... :>))

 

[chuter]

I used my new trailer-hitch-mounted hoist today! Thanks to all who gave input.

I ended up using a 3 inch square steel tube; 14ft long, .125 wall. I imagine I could have used half that wall thickness but I wanted to over-build.
The down side of that is: that boom is a little heavy!

I had a trailer ball mount that I welded a piece of square tube to so the square beam fits over the piece on the ball mount, and a bolt goes through them both.

I used 2 3/16” cables that go over the tool box on the front of the bed, down between the bed and the cab and attach to eye bolts that are mounted to the frame rail. The other end of the cables ties to the top of the boom.

I have ¾” angle going from the top of the bed on each side to a piece of angle welded to the boom. This is for side-to-side stability.

I put a jack stand under the ball mount so the truck suspension doesn’t sag.

I had a chain hoist hanging from the top of the boom.

Works great! Lifted about 600lbs of me and gyro with no problems.

Sorry the pics aren’t better; it was cold and we were working in the hangar, and the light coming through the door sort of washed out.

Thanks again everyone!