Electric retract sweep

[ericrw]

I'm wanting to order a pair of electric retracts for my FMS 74" wingspan Mustang (weight 1600 grams). I'm thinking of getting 15 to 25 size but I don't know which to choose in respect of the choice of 85 or 90 degree. I don't understand without looking at a pair what the difference would be . Can you help ?? Eric.

[David Ashby - Moderator]

Hello Eric, the P-51 has some dihedral so you'd only need 85-degree retracts otherwise the legs will move round too far and point outwards diagonally, if you see what I mean.

Having said that, I don't have my FMS P-51 at the moment and assume the model follows scale form in this respect?

 

That's a 57" span isn't it?

 

 

 

 

 

Edited By David Ashby - RCME Administrator on 27/02/2011 14:08:26

[ericrw]

Thanks for that David;yes it should have read 57". Your reference to the 85 degree retracts. In one of the build blogs that I've seen recommended putting a 4mm ply shim to increase the rake forward. I did this and it did help in landing and stopped it going nose-up. So does this make any difference in your advice ?? Eric.

[David Ashby - Moderator]

No difference Eric, that's a common ploy where warbird retracts are concerned and to stop a nose-over.

[Tim Mackey]

Posted by David Ashby - RCME Administrator on 27/02/2011 14:07:26:

Hello Eric, the P-51 has some dihedral so you'd only need 85-degree retracts otherwise the legs will move round too far and point outwards diagonally, if you see what I mean.

Having said that, I don't have my FMS P-51 at the moment and assume the model follows scale form in this respect?

 

That's a 57" span isn't it?

 

Or, as its known in the motoring world - negative camber