Aha! Good point, the l.e. devices are getting the full force of the air flow; therefore, perhaps a heavy duty servo is required. A better choice would be a locking device-but how? I'm also building a Douglas Skyray F4D which had spring operated l.e. SLATS, for high AoA carrier landings, they were problematic in a dogfight, supposedly. The issue here is, I think, how can one calculate, duplicate or measure the force of the airflow against these devices, a home built windtunnel?