Per Strommen

On my 1/4 scale Kerner Vampire the main wheels are 6 inch and heavy. The 5/8 in Robart leg and wheel weighs 580 grams(22oz)!
This has given me trouble with consistent gear retraction. The Robart 635 would sometimes be unable to lift the assembly, worked in the shop but could fail when flying.
I tried a hydraulic system, but apart from the WOW factor things did not improve as the maximum pressure was the same as in the pneumatic system. Scale factor improved considerably however.
So I needed stronger rams. Reading about electric retracts here on RCU drove me in the direction of LADO actuators, and after some e-mails the order for 3 ea 666 electric actuators was placed. I also ordered the programmer and the die tap for the 6-32 thread. Very positive experience with LADO, Christope and Stephane answer mails promptly and even tested my weight and published the video of the test on uTube for me to see. Excellent service!