In Escape to Witch Mountain (1975), around 1h 19m, there is scene with helicopter (Hughes MD500) in inverted flight which lands upside down and keep spinning. While flight itself is visibly "fake" after landing it looks too real for 40 year old movie, especially with humans running around heli.
Aviation.SE answers can be summarized shortly as: Helicopter rotating upside down will break rather fast and "physics" of scene are not mach with real machine. This lead to common opinion that scene was filmed using some prop/model.
- Are there any information available about this prop?
- Was it made from gutted out real helicopter or fully custom made?
- Are there "behind the scenes" materials available?