Drag Chutes

[a1]

What up with these drag chutes? I see some fighter aircraft like the Eurofighter use them when they touch down when it isn't necessary.


Also can drag chutes be modified for commercial jetliners in case of runway over run?

[Hagar]

I don't think they would use them when it isn't necessary. Not using the chute would save a lot of bother collecting & re-stowing it.

Braking chutes are fitted to military aircraft without reverse thrust. The alternative would be an arrester hook as used on several US types. Then you would need runways fitted with arrester wires.  Never seen chutes used on civil aircraft except for the anti-spin chutes fitted during testing.

[beaky]

It's true- sometimes needing a drag chute is just a design compromise, in order to get the cruise performance you're after. It's similar to the reality of some large aircraft having a higher acceptable takeoff weight than landing weight.

As for fitting airliners with drag chutes: I think by the time you realize you need it, it'd be too late for it to help. Airliners don't generally go very far when they overrun; in fact, that's what causes the damage and danger. They're not made for "off-roading".

[a1]

I thought military fighter aircraft have breaks to brake them during landing.

[Hagar]

I thought military fighter aircraft have breaks to brake them during landing.

You mean brakes. The chutes are used to save wear & tear on the brakes & tyres. Much like reverse thrust is used on the heavy airliners.

[C]

Indeed. It's best to lose as much energy by aerodynamic methods (chutes, reverse thrust etc) then apply the brakes at a much lower speed (around half to three-quarters of the actual landing speed perhaps). This saves a lot of wear on the brakes, and for safety's sake, keeps the brake and wheel units a lot cooler.

[beaky]

I thought military fighter aircraft have breaks to brake them during landing.

You mean brakes. The chutes are used to save wear & tear on the brakes & tyres. Much like reverse thrust is used on the heavy airliners.

Again, it's about compromise, I think... some aircraft have brakes that, due to weight or space restrictions, are perfectly all right for stopping, but not good for slowing down just after landing at high speeds with a massive aircraft. Definitely saves wear and tear, but chutes and reverse thrust are simply a way to provide initial decelleration without having massive wheels and brakes (relative to the size of the aircraft).

The bogeys on an A380 are huge, mostly just to support the machine's weight... but imagine how big they'd need to be to do all the work of stopping one!!

[expat]

Reverse thrust is just an alternative method of slowing down. All aircraft with reverse thrust are capable of stopping on any runway that they are designed for using brakes only. Reverse thrust is used to extend the life of a heat pack (brake unit). Carbon brakes for example, one unit costs more than a very nice family car with every accessory it can come with. The longer you can use one, well the $$$ saving speaks for it's self. The same goes for Drag chutes, a Euro Fighter that cannot stop after chute fails to deploy, could get rather expensive (however I would not be at all surprised if the chute was a weight and balance thing with the EuroFighter or even a back hander when it was designed )


Matt

[C]

The same goes for Drag chutes, a Euro Fighter that cannot stop after chute fails to deploy, could get rather expensive (however I would not be at all surprised if the chute was a weight and balance thing with the EuroFighter or even a back hander when it was designed )

With the Typhoon of course it wasn't always expected to be operating off 9000ft NATO standard runways.

[DaveSims]

There is a tremendous amount of energy in an aircraft moving over 100 mph on landing.  That is why aircraft designers have created drag chutes, thrust reversers, and spoilers, all to use other methods to diminish that energy and slow the aircraft.  At work, if we a jet coming in without thrust reversers, flaps, or spoilers, we go on alert for a hot brake situation.

[chornedsnorkack]

Which civil planes operate drag chutes? Tu-104 does, but which others?

[expat]

[quote]There is a tremendous amount of energy in an aircraft moving over 100 mph on landing.

[beaky]

I guess I stand corrected... but only about reverse thrust, not drag chutes.

[Hagar]

This is what you call a braking parachute.