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Realms09 · November 21st, 2007, 20:04

While this may or may not affect which engine is termed "critical," it is generally relavent to what y'all are discussing. In a crosswind jet engine takeoff there are two opposing directional effects going on.

1. A weathervaning effect due to the rudder and surface area aft of the CG.

2. An anti-weathervaning or downwind steering effect due to engine intake momentum drag. Imagine the aircraft when it is sitting still on the runway in a crosswind. The air enters the engine moving left or right (the direction of the wind) and exits the engine heading straight back. The air has changed directions as the result of a force exerted on it by the engine intake. The reaction of that force causes the aircraft to yaw downwind since the intakes are generally forward of the CG.

This explains why loss of the downwind engine can be worse than the upwind, or vice versa.

November 21st, 2007, 20:04	#6
Realms09 Junior Member Join Date: Aug 2002 Posts: 212	Re: Jet Aircraft Critical Engine While this may or may not affect which engine is termed "critical," it is generally relavent to what y'all are discussing. In a crosswind jet engine takeoff there are two opposing directional effects going on. 1. A weathervaning effect due to the rudder and surface area aft of the CG. 2. An anti-weathervaning or downwind steering effect due to engine intake momentum drag. Imagine the aircraft when it is sitting still on the runway in a crosswind. The air enters the engine moving left or right (the direction of the wind) and exits the engine heading straight back. The air has changed directions as the result of a force exerted on it by the engine intake. The reaction of that force causes the aircraft to yaw downwind since the intakes are generally forward of the CG. This explains why loss of the downwind engine can be worse than the upwind, or vice versa.