11

Possible? Yes! But not recommended. There is nothing technical that would stop you from doing it. Thrust Reversers can be selected any time on the ground and there is enough thrust available to move the aircraft backwards. It is also not technically prohibited to do so: Reverse Thrust Intentional selection of reverse thrust in flight is prohibited. (Boeing ...


9

As always, it is a trade-off. On the positive side, thrust reversers allow you to slow down faster and reduce brake wear. On the negative side, there are costs to install and maintain them. They add weight, which increases the required take-off length reduces the maximum payload and increases fuel consumption. Dassault found the optimum for their design in ...


5

There's a lengthy paper on the NASA web site that investigated this. There's a lot of detail covered in that paper so I'm not going to reproduce any of it here, but the main positive points that emerge are: Improved safety margins on landing1 Reduced wear on brakes and tyres Reduced brake temperature leading to faster aircraft turn around. Even when ...


4

The ambient air will only move through the engine from back to front when the aircraft is on the ground. Even then, the engine would have to be off for that to happen. Otherwise, the thrust from the engine would be too great. Even the electric or air starter should have enough torque to overcome the ambient air pressure before fuel ignition is achieved. Go ...


4

Only when on the ground, and at the inlet end, where a strong wind from the side and behind could influence the engine's ability to draw air in the front at low power settings. Some engines have limitations or restrictions on how power is applied during takeoff in strong tail or quartering winds, because of initial flow disruptions at the front from air ...


4

Yes. Most of the noise you hear from aircraft is not mechanical noise from engines but disturbances in airflow around the airframe and engine outlets and inlets. The airflow from reversing jet engine is much more turbulent than when the engine is forward pushing and thus more noisy.


3

"Possible" as in, "last flight out of Saigon, we'll try anything because the alternative is worse," maybe. But Boeing doesn't publish any procedure for it, as far as I've ever seen, and they generally take a very dim view of using T/R's at low speed. It isn't in any published non-normal procedures. I've also heard, anecdotally, of one ...


3

To generate a given thrust, a turbofan accelerates less air but faster than a turboprop. This means that turbofans can fly faster. However thermodynamically it is more efficient to accelerate a greater mass of air slower, so turboprops are more efficient and that translates into lower fuel burn.


2

It’s all dependent upon what operating speeds your aircraft will be in. Propellers can move a great volume of air at slow speeds but accelerate the gas to a lower exit speed than does a turbojet or a turbofan. This is the principal reason that a helicopter is the most efficient means of VTOL flight out there for a heavier than air aircraft. But as speeds ...


2

If I may paraphrase the Wikipedia article on the accident... The Fokker 100 aircraft had a safety feature to throttle back an engine in the case its thrust reverser deployed during climb or cruise. Unfortunately, there was no indicator or alarm to notify the crew of the unintended thrust reverser deployment. On the accident takeoff, a faulty switch cause ...


1

An aircraft approaching to land with a reverser deployed or unlocked, particularly one that's deployed unintentionally, will be at idle power, or shut down on the deployed reverser. A go-around or missed approach is conducted in the same manner as if the engine is shut down for any other reason.


1

Whereas an airplane with a tailwind is moving at it's true airspeed (or EAS) plus the wind value, the airplane never actually experiences the tailwind, other than as expressed by its speed over the ground. An airplane on the ground during engine start, with a tailwind, can experience a slightly elevated start temperature up through about 35% during the ...


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