RE: Going electric!
Per
This is a very informative post and useful for me. I have 3 planes with large wheels. I anticipated having similar problems to you. I have used Behotec C50 retracts which have been very strong and reliable so far. My Horten has a 6 inch nose wheel and a long leg. However it has a second long air ram to assist the noseleg. The mains are 4 inch. This arrangement has worked without any problems. The mains wheels and brakes were made by me.
Recently I made the Arado 555 which has a 4 wheel bogie. I used very light weight wheels on the inside and on the outside I made my own 4 inch wheels and brakes using Dubro tyres. So far this works in the workshop but it has not flown. It is asking a lot though of the pneumatic system.
I have just finished the wheels on the Boulton Paul P111 which are 6 inch mains (scale 1: 4.2). Again they are made by me using the dubro tyre I ended up at a weight of just under 300 grams for the wheel hub and axle. My tests showed that the wheels would lift up at 60 psi leaving plenty in hand. The wheel rims are as thin as I thought sensible so there is no chance of making them lighter.
If I have problems with either the Arado or the P111 I was planning to install electric retract motors in place of the cylinders so your post is very helpful.
I love the Vampire and especially like the nose leg you have used.
John