RC contra-rotating, variable pitch prop for a Westland Wyvern
https://www.youtube.com/watch?v=1y_acrzgpFo
https://www.youtube.com/watch?v=1y_acrzgpFo
RC contra-rotating, variable pitch prop for a Westland Wyvern
https://www.youtube.com/watch?v=1y_acrzgpFo