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Realms09 · November 22nd, 2007, 01:41

What you've listed mathces weathervaning, the first effect I mentioned. However, the effects of "weathervaning" and "intake momentum drag" are completely separate. Weathervaning will vary with wind velocity and surface area distribution, while "intake momentum drag" will vary with wind velocity and thrust setting. At high thrust settings the engines will be processing a lot of air, all of which is accelerated from moving somewhat sideways to moving purely axially. The resulting force on the intake is downwind, so on for wing mounted engines the yawing moment is away from the wind, opposite the weathervaning tendency. This explains why B767 found the downwind cut more difficult. However, on the business aircraft you likely fly the engines are fuselage mounted with the inlets aft of the CG. The "intake momentum drag" would reinforce the weathervaning tendency and it would be harder to differentiate the effect.

November 22nd, 2007, 01:41	#8
Realms09 Junior Member Join Date: Aug 2002 Posts: 212	Re: Jet Aircraft Critical Engine What you've listed mathces weathervaning, the first effect I mentioned. However, the effects of "weathervaning" and "intake momentum drag" are completely separate. Weathervaning will vary with wind velocity and surface area distribution, while "intake momentum drag" will vary with wind velocity and thrust setting. At high thrust settings the engines will be processing a lot of air, all of which is accelerated from moving somewhat sideways to moving purely axially. The resulting force on the intake is downwind, so on for wing mounted engines the yawing moment is away from the wind, opposite the weathervaning tendency. This explains why B767 found the downwind cut more difficult. However, on the business aircraft you likely fly the engines are fuselage mounted with the inlets aft of the CG. The "intake momentum drag" would reinforce the weathervaning tendency and it would be harder to differentiate the effect.