The first stock propeller planes only had a single engine as I was trying to get it to even fly. The early propellers were very unstable and couldn't produce enough thrust to takeoff (back in 0.21). After the reaction wheels got buffed again (0.24), I was finally able to get the plane to takeoff. Unfortunately, my lack of experience in wheel bearings meant that they only had rudimentary "dry" bearings, which were much more unstable than the current ones by Sgt_flyer. Nonetheless, it does work, but the propeller would jam if it went too fast or too slow but can usually be unjammed by briefly rotating the propeller the opposite direction. I can post the lastest prototype with Sgt_flyer's latest dry bearing and the original craft.