The place for technical discussions about GA and flying.
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By andyhill296
#1911390
Hi all.
I'm looking at replacing the lower undercarriage legs on my jodel D112.
Sandalwoodservices sell one. The other POA.
Not sure if they are still trading.
I want to replace the legs as the toed in one's fitted are chewing up my very expensive tyres as I mainly fly from tarmac.
Any pointers on new straight legs or where to get the engineering drawings would be much appreciated.
By thegasguy
#1914066
Andyhill296;
Hi; the toe- in is a design feature and very necessary, you won’t buy ‘straight’ legs.

My tyres - luckily very cheap !- also get worn out on tarmac, so I use grass runways whenever possible.

You will hear many theories on the toe- in ;
Here is mine.

Imagine landing; imagine swinging to the left on the landing run; the left tyre gets straighter - in line with the runway, so there is less rolling resistance.
The right tyre turns even more ‘sideways’ and offers more resistance -result, a natural turn to the right back onto the runway.
And the of course the reverse in the other direction.

Other opinions are available.

I bought a spare new outer and sundry used legs as insurance- never needed any of them. Accept the cost of tyres as part of flying and crack on without worrying too much is my advice.
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By rf3flyer
#1914076
@thegasguy I always assumed it was because the point of contact between the tyre and the ground being outboard of the centreline axis of the u/c leg would result in a slight twist or straightening of the wheel upon landing.
Please note my use of the word 'assumed'. I don't know.
#1914114
thegasguy wrote: Accept the cost of tyres as part of flying and crack on without worrying too much is my advice.

There speaks the man who doesn't have to buy 420 x 150 tyres!! I remember weeping a couple of years ago when I had to buy a pair. The cheapest I can find online now are £299 each :(

If I remember correctly, the Jodel aircraft built by Wassmer had round legs with a scissor arrangement to prevent the wheels rotating. I was told that it was possible to adjust the toe in by varying the number of washers between the two halves.

Alternatively I saw the legs in the photo at Friedrichshaven which are available for Jodels and it looks like it may be possible to alter the toe in. However be prepared to pay 4000 Euros for a pair.

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