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Old Jun 09, 2001, 07:09 AM
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Doc Watson's Avatar
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Home made oleo legs......

I wanted some oleo legs for my X32b Vtol project ( www.awatson1.fsnet.co.uk ) and after spending loads of money on 3 brushless motors, 3 ESC's, fans etc I wanted to build my own.

I used two pieces of brass tube (K&S) with one fitting inside the other. After much dremel cutting and some fine filing I think the results are quite good. I will post some pictures later today to show the results.

The tubes enclose a spring which has a maximum 3kg force (to fully compress it) and I only hope that any heavy landings will be absorbed. The total cost for all the parts required must have been less than $10!!!!

I also made my front wheel attachment from carbon fibre tows with excellent results, again pictures will follow later today.

Doc
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Old Jun 09, 2001, 07:20 AM
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Quote:
Originally posted by Doc Watson:

The tubes enclose a spring which has a maximum 3kg force (to fully compress it) and I only hope that any heavy landings will be absorbed.
Doc
When we used to make our own oleos for GDF, we used a spring rate of 6xmodel weight per in.

So a 5lb model would use a 30lb/in spring on each main leg.

Cheers

Gordon
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Old Jun 09, 2001, 07:33 AM
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My expected (or should I say planned) AUW is 9lb!! so do I need stiffer springs?, remember its not landing 'conventionally' its the VTOL thing. I also have three UC legs which will spread the load, this makes a difference, right?

I just calculated that my spring compresses fully to about 1/2 inch so thats about 13lb/inch stiffness. Still dosent sound as if its stiff enough using your figures.

Doc

[This message has been edited by Doc Watson (edited 06-09-2001).]
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Old Jun 09, 2001, 11:21 AM
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Springs alone make for rather poor energy absorption characteristics. Dampening of some sort would be required to prevent 'bounce back'.. perhaps the coil- over units from RC cars might be worth considering as an alternate.. barring price considerations some of the available units are adjustable for compression/rebound as well as spring rate... wieght and bulk might be a consideration tho... certainly worth exploring.
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Old Jun 09, 2001, 12:17 PM
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For damping you can stuff the oleo tube with a foam like EPP that can compress with a slow full recovery. You can actually use the foam instead of springs. This would be similiar to what is often used in bicycle suspensions.
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Old Jun 09, 2001, 07:37 PM
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Hear is the one I made earlier.......



Doc

[This message has been edited by Doc Watson (edited 06-09-2001).]
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