airbrakes: how to use and how they work

[osvep]

In the checklist of a mig 29 fulcrum model I read "use them (on flight in the context of the explanation)to reduce speed to 150 knots... I follow the instruction at about 400 knots whe I saw the plane trembling but speed does not modifies and the amount of N1 remains
at 44% even I tried to reduce pushing f2 continously.A few seconds after repeating both commands the plane began to dive and I could'nt stop till it crushes!Anyone can explain how all this airbrakes works and must be used.Thanks a lot.    Osvep (novice pilot)

[Mobius]

I use them to slow down when I'm on approach or when I'm landing once I'm ready to touch down and I'm going a little too fast.  You could also use them in a steep dive if you're going too fast.

If you decrease your speed too much you won't be going fast enough to create lift and you will stall (fall out of the sky and crash ).

If your airplane starts to shudder, you should increase the throttle and nose down to help increase your airspeed and decrease your angle-of-attack so you don't stall.

Hope that helped.  Other people might know better than me too though.

[beefhole]

Never use airbrakes when you have more than 15 flaps in.  In RL, it is basically forbidden to use full deployment of them while you're in the air, they would probably get sheared off if you were going to fast-but in FS, we don't have the luxury of the "flight detent" setting, so you should only deploy the speedbrakes for very short periods of time, and never when you have A/T (autothrottle engaged), because it'll just throttle up and cancel out any speed reduction.

In short-don't leave them deployed for too long.  They "spoil" lift.  Ya know, that great thing that makes the airplane fly.  Only for short periods of time while in flight.

EDIT: Oops.  Just read that he was refering to fighter jets, I always automatically think commercial.

Someone else would be much better qualified to explain fighter ops than me, but everything I wrote still applies to the big(ger) jets.

[C]

All depends on what type of aircraft you're flying - look at a Tornado or Alpha Jet for example, and you'll see they have the airbrakes deployed until they're on the ground...

[jrpilot]

All depends on what type of aircraft you're flying - look at a Tornado or Alpha Jet for example, and you'll see they have the airbrakes deployed until they're on the ground...

Maybe that is true, I don't know military aircraft, but when a commercial aircraft lands it automatically deploys its speed breaks, so maybe that is what you saw, I don't know


But in reference to the air breaks, they have nothing to do with speed, well atleast they aren't supposed to be used to drop speed.  Their purpose is to allow the pilot to increase his vertical speed on descent.  They work by disturbing wind flow over the wings

[C]

Maybe that is true, I don't know military aircraft, but when a commercial aircraft lands it automatically deploys its speed breaks, so maybe that is what you saw, I don't know

As I say, those are two military aircraft which do it as part of their standard procedure. As you say on commercial aircraft they deploy on touch down to "lift dump"...


[quote]But in reference to the air breaks, they have nothing to do with speed, well atleast they aren't supposed to be used to drop speed.

[Staiduk]

Some people are confusing 'airbrakes' with 'spoilers'.

'Airbrakes' are basically big whompin' pieces of metal that get turned into the airflow; create drag and slow the aircraft down. (Like the one on the F-15. Now there's a big whompin' piece of metal! )

'Spoilers' on the other hand are placed on the top and frequently bottom of an airfoil. Their goal is to - as has been stated - 'spoil' lift; increasing the descent rate.

Easy to confuse the two; but they're very different in design and use.