A380900 From France, joined Dec 2003, 1110 posts, RR: 1 Posted (4 years 1 month 4 hours ago) and read 2216 times:
In all the videos I've seen on youtube about the A400M at Farnborough, I've been struck by a strange effect: it looks like the propeller is moving at very slow motion. I guess this has to do with the frequency of the movie cameras and the number of blades. Can anyone shade light on this amazing effect? (or is it: 24 pics per seconds with 8 blades => three times slower?)
I think it's the first time there is a propeller with that many blades. Does that explain it? It could be the speed of rotation as well but it does not seem to change in different flight configuration (landing, take-off etc...).
A380900 From France, joined Dec 2003, 1110 posts, RR: 1
Reply 2, posted (4 years 1 month 3 hours ago) and read 2146 times:
Ok, now this beats the A400M hands down! So I guess it is not a matter of the number of blades. Can someone explain. I vaguely remember studying that in physics when I was 15 but I could definitely use of refresher. Also, I don't remember seeing that during first flight. Different video equipment?
Also with a close-up, one could see pitch variation be it for the helicopter or the propeller... I guess people testing turbo prop engines have been using that for a while. Or turbo fans for that matter.