Do planes have brakes on the wheels?
Do planes have brakes on the wheels?
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Discussion

MitchT

Original Poster:

17,114 posts

238 months

Wednesday 1st December 2010
quotequote all
Possibly a silly question, but do planes have brakes on the wheels? I know they use ‘reverse thrust’ and air brakes on the wings to slow down after landing, but do they rely on mechanical braking too? The reason I ask is because I hear of aircraft skidding off the end of the runway in icy conditions, but surely if the braking was 100% aerodynamic then the grip level on the runway would be irrelevant and the plane would stop just as quickly regardless of the condition of the surface.

Roberty

1,180 posts

201 months

Wednesday 1st December 2010
quotequote all
MitchT said:
Possibly a silly question, but do planes have brakes on the wheels? I know they use ‘reverse thrust’ and air brakes on the wings to slow down after landing, but do they rely on mechanical braking too? The reason I ask is because I hear of aircraft skidding off the end of the runway in icy conditions, but surely if the braking was 100% aerodynamic then the grip level on the runway would be irrelevant and the plane would stop just as quickly regardless of the condition of the surface.
Yes they do.

anonymous-user

83 months

Wednesday 1st December 2010
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Yes.

Hard-Drive

4,291 posts

258 months

Wednesday 1st December 2010
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No need to...that's what the conveyor belt is for!

Seriously, yes they do, usually operated by the toes, at the top of your rudder pedals. ABS technology was around in planes long before vehicles. Modern airliners stop via a combination of speedbrakes on the wings, reverse thrust from the engines, and wheel brakes.

xr287

875 posts

209 months

Wednesday 1st December 2010
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Yes I thought ABS was first developed for planes. Which would be a bit silly if they didn't have brakes to apply it on.

Eric Mc

125,600 posts

294 months

Wednesday 1st December 2010
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Of course. In fact, disc brakes were first used on aircraft as were ABS systems.

However, before WW2, most smaller aircraft did not have proper brakes. Aircraft like the Sopwith Camel and SE5A relied on a wooden tail skid dragging in the grass to slow them down. Even into the 1930s this crude method of slowing an aircraft down was common. For instance, the DH82 Tiger Moth doesn't have brakes.

MitchT

Original Poster:

17,114 posts

238 months

Wednesday 1st December 2010
quotequote all
Interesting, thanks smile

dvs_dave

9,040 posts

254 months

Wednesday 1st December 2010
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Carbonfibre braking systems as used by racing cars today were also first used in aircraft.

MOTORVATOR

7,602 posts

276 months

Wednesday 1st December 2010
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Who needs brakes?


knight

5,235 posts

308 months

Wednesday 1st December 2010
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If I remember I'll take a pic of an aircraft brake and post it up in a day or two. Or you could have a quick look at google images to see what a brake unit looks like. And before you ask if you could fit one to your car wink, then I have to say that the weight of a single unit that is fitted to our fleet of A319/A320s is 90kg! And those on an A330 are 158kg!

john_p

7,073 posts

279 months

Wednesday 1st December 2010
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http://www.youtube.com/watch?v=hRzWp67PIMw

This vid is from a "rejected takeoff test" when the Airbus A340 was being certified .. one test for all aircraft is to replicate the maximum load on the brakes (occurs following a rejected takeoff at max weight) and check that the aircraft can safely sit and wait for a period of time before the firefighters can get there. The brakes get so hot that the tyres burst, but this should normally be a controlled event (due to fusible plugs in the tyres).

As you can see, the results of this test were not entirely successful hehe

Following modifications it was fine, of course.

Cupramax

10,999 posts

281 months

Wednesday 1st December 2010
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dvs_dave said:
Carbonfibre braking systems
Dont you mean Carbon ceramic?....

Matt Harper

7,025 posts

230 months

Wednesday 1st December 2010
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Yertis

19,704 posts

295 months

Wednesday 1st December 2010
quotequote all
knight said:
I have to say that the weight of a single unit that is fitted to our fleet of A319/A320s is 90kg! And those on an A330 are 158kg!
Which is about a tenth of the weight of a London bus. smile

prand

6,244 posts

225 months

Wednesday 1st December 2010
quotequote all
xr287 said:
Yes I thought ABS was first developed for planes. Which would be a bit silly if they didn't have brakes to apply it on.
Probably a PH related urban myth, but didn't the Jensen Interceptor have modified aircraft ABS when it was one of the first production cars to have it installed as standard?

Eric Mc

125,600 posts

294 months

Wednesday 1st December 2010
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My Caterham has an airbrake - although it's usually referred to as the windscreen.

aeropilot

40,503 posts

256 months

Wednesday 1st December 2010
quotequote all
prand said:
xr287 said:
Yes I thought ABS was first developed for planes. Which would be a bit silly if they didn't have brakes to apply it on.
Probably a PH related urban myth, but didn't the Jensen Interceptor have modified aircraft ABS when it was one of the first production cars to have it installed as standard?
True, but not the Interceptor as such, it was the Jensen FF which used the aircraft derived Dunlop Maxaret ABS system along with the Ferguson Formula awd system.

xr287

875 posts

209 months

Wednesday 1st December 2010
quotequote all
Yertis said:
knight said:
I have to say that the weight of a single unit that is fitted to our fleet of A319/A320s is 90kg! And those on an A330 are 158kg!
Which is about a tenth of the weight of a London bus. smile
A london bus weighs 900kg or 1580kg? Do you mean a 100th?

Yertis

19,704 posts

295 months

Wednesday 1st December 2010
quotequote all
xr287 said:
Yertis said:
knight said:
I have to say that the weight of a single unit that is fitted to our fleet of A319/A320s is 90kg! And those on an A330 are 158kg!
Which is about a tenth of the weight of a London bus. smile
A london bus weighs 900kg or 1580kg? Do you mean a 100th?
Probably, I can't remember how much a London bus weighs now.

Hang on.

An unladen Dennis Trident weighs 14560kg, apparently.

knight

5,235 posts

308 months

Wednesday 1st December 2010
quotequote all
A nice new brake unit still in it's box



Now not looking quite so good