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Old 20th Jul 2011, 08:31
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Trim Stab
 
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Yes, I can see that the C130J would have asymmetric problems as all four props rotate clockwise - presumably it was too expensive to make props 3 & 4 rotate anticlockwise.

But if the designer has the luxury of choosing the direction of prop rotation on a multi, you generally make the props supra-convergent to minimise P-factor*

What I don't understand on the A400M is that 2 & 3 are supra divergent. I guess I'll have to ask on the Flight Test forum.





* Exceptions being multis designed as ground attack aircraft such as P-38 Lightning, Henschel 129 & OV-10A Bronco where supra divergent props gave greater stability as a gun platform.
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