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Airbus A400M with tilted engines

Picture: Youtube.

Firstly, are the engines really tilted down? I have tried to check another picture over the net, seems they are really tilted down slightly. But need confirmation from you experts, however.

Second, if it is true, what is the reason?

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    $\begingroup$ In flight, they are probably horizontal. $\endgroup$ – Jeffrey Sep 22 '19 at 3:34
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Just about all propeller driven airplanes big and small have the engine thrust line canted down a couple degrees from the wing chord line (not necessarily the longitudinal axis - that depends on the wing incidence), roughly equal to the cruising AOA, so that the thrust line is aligned a little closer to the free stream at cruise. On the A400 it looks like the nacelles are creating a bit of an optical illusion that exaggerates the effect, although the propellers do appear to be canted a bit relative to the fuselage. Thrust lines may also be offset to mitigate undesired pitching moments caused by thrust.

Single engine airplanes with the engine on the nose also often cant the engine to the side several degrees as well, to compensate for P factor and torque effects, reducing the amount of fin offset required at the tail. Look straight down on a typical single like a 172, with the prop stopped horizontally, and you can see the prop isn't quite parallel to the wings. Once you gain awareness of this you start to notice that most single engine planes you see have engines that are cockeyed, as if they were bent.

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  • $\begingroup$ Canted down several degree from line chord, or several degree from longitudinal axis? $\endgroup$ – AirCraft Lover Sep 23 '19 at 2:19
  • $\begingroup$ Thank you for the info about mount the propeller sideway to overcome the P-Factor. $\endgroup$ – AirCraft Lover Sep 23 '19 at 2:20
  • $\begingroup$ Chord. As I said, "not necessarily the longitudinal axis" which is a different. AOA is related to chord line, not long axis. $\endgroup$ – John K Sep 23 '19 at 3:04
  • $\begingroup$ Thank you John for the nice explanation. $\endgroup$ – AirCraft Lover Sep 23 '19 at 12:03
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As Jeffrey points out in his comment to the question:

In flight, they are probably horizontal.

When that plane is at cruise conditions, it will be in a very slightly nose-up pitch attitude. the thrust line from the props will then be in the direction of travel.

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  • $\begingroup$ That makes sense. But who is Jeffrey? $\endgroup$ – AirCraft Lover Sep 22 '19 at 4:54
  • $\begingroup$ he's the author of the comment that preceded my answer. $\endgroup$ – niels nielsen Sep 22 '19 at 20:31

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