Talk:Takeoff

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Contents 1 Limited to fixed-wing aircraft? 2 Rotation 3 Removed text 4 take-off, take off, or takeoff 5 Take off versus weight 6 fuel consumption during take off 7 Pictures - too many?

[edit] Limited to fixed-wing aircraft?

This article only deals with fixed wing takeoffs. If it isn't limited in the tile it should cover all forms of flight including helicopters, birds,aircraft carrier takeoffs (steam catapult and skijump), V/STOL... balloons and carrier takeoffs are illustrated but not covered inthe text. Cyclopaedic 19:26, 28 April 2007 (UTC)

[edit] Rotation

When rotated, an aircraft will NOT "continue to rotate" unti it stalls. Rotation is typically applied until the nose is at a specified position. Mike Stramba 16:43, 1 Nov 2003 (UTC)

Also, rotation does not take place "about the aircraft's centre of gravity" - it rotates around the axles of its main wheels! Think about it. These are behind the centre of gravity (unless it's a taildragger), otherwise the plane would tip over on the ground. Once actually flying, then things are different, but rotation is something that occurs below flying speed. GRAHAMUK 11:31, 8 Nov 2003 (UTC)

Graham, hmm interesting thought about c.g. vs wheels. I don't have the technical answer, but I think I'll look into it. I disagree that it occurs "below flying speed". Ok, I guess you mean the speed neccessary to get the plane off the ground, but *some* speed is neccesary over the wings to generate enough force to get the plane to rotate. So since it *is* in fact the lift of the wings that is causing the plane to rotate, I would (guess ??) that the plane is actually rotating about the c.g. This is more or less a trivia question anyway <g>, but I guess it *is* important for anyone designing an aircraft !

I know this is a very old discussion now - one I haven't come back to until now. Yes, there is lift, probably not enough to fully support the aircraft's weight at this stage however. But rotation is definitely about the wheel axle, not c.g. - if it were about the c.g. it would require that the wheels sank some distance into the concrete, which can't happen. Thus the aircraft nose is actually levered upwards by the lift force acting against the fulcrum of the main wheels. But yes, you're right that really it's a small point. Graham 22:31, 8 December 2005 (UTC)

Two items... It's a common misinterpretation of the equations of motion that all objects rotate about their center of mass. We typically write those equations for the mass center because it allows us to decouple the translational and rotational equations. It's just a mathematical convenience, and shouldn't be interpreted as anything else. Think of any pendulum you've ever seen. It's rotational center is about as far from the mass center as you can get. Also, takeoff rotation for a fixed-wing transport category aircraft is calculated to occur such that three seconds after rotation is initiated the airplane is in the liftoff attitude and at the liftoff speed. (Take a stopwatch on your next commercial flight if you don't believe me.) So the whole question of whether or not the airplane is at 'flying speed' is irrelevant as well as poorly stated.

[edit] Removed text

In cost controls a take-off is the action of counting and measuring from drawings or specifications key words: estimating, construction, building, civil engineering, architecture, engineering Ref: Jose R. Teres 26/Oct/2005 http://www.mikeholt.com/news/archive/html/master/electricalestimatingandpm4.htm

- Ste|vertigo 19:36, 8 December 2005 (UTC)

"Autorotation is where an aircraft will do this by itself when it reaches some speed." I think you have this confused with autorotation of a helicopter. An autorotation is used when the engine fails, or when a tail rotor failure requires the pilot to effectively shut down the engine. It is very similar to gliding in an airplane. I know of no aircraft that will make an automatic takeoff.

removing reference to autorotation, as not relevant Cyclopaedic 19:26, 28 April 2007 (UTC)

[edit] take-off, take off, or takeoff

article mentiones takeoff but also take-off . Is it takeoff, take off, or take-off? i need this for an article. thank you.

Take off when a verb. Takeoff or take-off when a noun. Cyclopaedic 19:02, 28 April 2007 (UTC)

[edit] Take off versus weight

"The take off speed is directly proportional to the aircraft weight; the heavier the weight, the greater the speed needed."

this seems rather misleading and perhaps outright wrong. ive always been under the impression that take off speed is proportional to the effectiveness of the aircrafts wings, the effectiveness itself being determined by the wing surface area primarily, and also by left-generating devices, geometry, etc. this is why planes as varied as a 737 and a 747 and an antonov 124 all have comparable take off speeds, but a concorde has a much higher take off speed.

at best, this statement would need to be amended to say that take off speed is directly proportional to aircraft weight and inversely proportional to the effectivensss of its wings. but arguably, the wing configuration is the overwhelmingly important criterion. Downward machine 18:45, 24 December 2006 (UTC)

For any given aircraft, the quote from the article is 100% true. Comparing unlike aircraft is not the intention of this statement, so perhaps it should be written more clearly ;)--chris.lawson 00:39, 26 December 2006 (UTC)

[edit] fuel consumption during take off

I have heard that airplanes consume 50% of the fuel during take off. Is that a myth? Or is it real?

59.93.41.59 08:03, 26 April 2007 (UTC)mohan (mohans@msn.com)

Myth, for anything resembling a normal flight. A perversely clever performance engineer might be able to construct a flight plan for which this statistic is true, but you would have a very hard time selling tickets for that flight.

In a normal flight the engines are at the highest power setting during takeoff. So while it's true that the rate of fuel burn is highest at takeoff, the total fuel consumed getting to your initial climb altitude isn't even remotely half of the total fuel load.

[edit] Pictures - too many?

Having four pictures of mid-sized Boeing and Airbus passenger jets taking off seems a bit excessive. Can we perhaps have some pictures of some smaller, non-military, planes taking off - maybe a microlight? 217.155.20.163 19:53, 5 June 2007 (UTC)