3
$\begingroup$

Eddy current brakes (wiki) --- a.k.a. magnetic brakes --- get quite some attention from train engineers. They are used on Shinkansens, roller coasters, and even (as far as I know) metro trains on Lane C in Prague. They basically consist of a magnet and a rotating disk, where these two never touch. The kinetic energy is converted to heat, as in conventional brakes. While Shinkansens give them up, from what I view it is in favour of recuperating brakes and whence it is irrelevant with respect to aviation.

I wonder whether anyone considered their use in aviation. To me it seems that it could be a good option.

$\endgroup$
  • 4
    $\begingroup$ I can see a couple of major problems with them. One is that the breaking force is going to be proportional to the size of the coil, thus much more weight. The second is that they won't hold at a stop, so you would still need regular brakes. $\endgroup$ – TomMcW Dec 26 '16 at 21:50
  • 1
    $\begingroup$ @TomMcW In that case they could be used on some wheels only maybe? (That's probably added infrastructure that's not worth it...) I understand it's not "all that easy", I just wonder how it is :-) $\endgroup$ – yo' Dec 26 '16 at 22:23
  • 3
    $\begingroup$ Related patent: Electromagnetic landing gear brakes held by Hamilton Sundstrand. $\endgroup$ – mins Dec 27 '16 at 0:23
  • $\begingroup$ Given all the crazy brake designs used over the years, I'm sure someone has tested them. $\endgroup$ – Mark Dec 28 '16 at 3:38
  • $\begingroup$ Advantages of eddy current brakes are that they don't wear and that, in the linear form, they can distribute the heat along the rail, avoiding local heat buildup anywhere. However, they are rather heavy and for larger braking forces need to be electromagnetic, so they need electric energy. Neither is a problem on a train (train engines have to be heavy to have enough traction), but both are problem on aircraft. And without rail, the second advantage can't even be realized. $\endgroup$ – Jan Hudec Sep 10 '17 at 20:58
1
$\begingroup$

Eddy current brake is a misnomer: it's a damper, not a brake as in a device that works on friction forces and can completely stop motion. Eddy current dampers do provide deceleration forces, by inducing whirly electromagnetic currents in a rotating wheel - they could provide extra emergency braking power without installing extra brake pads.

However, aircraft wheel brakes are dimensioned for emergency deceleration, can provide this adequately using friction pads, and their main problem is getting rid of the heat that is created. Eddy current dampers create the same amount of heat...

$\endgroup$
1
$\begingroup$

You are proposing a solution to a nonexistent problem. Commercial jet planes do not ever run out of runway because their brakes get an insufficient grip on their wheels. A report of a "braking failure" is the result of the wheels getting an insufficient grip on the ground.

Eddy current brakes are invariably much heavier than friction pad brakes of the same gripping power. Airline operators would rather monitor and replace friction pads than spend the fuel to carry magnetic coils about. And some kind of friction brake would still be needed, since grip of the eddy current brake fades to nothing at full stop.

If a new technology were ever needed to bring heavy landing aircraft to a stop, operators might consider using an electromagnet on the plane to create eddy currents in a specially prepared metal runway. I don't think this would actually work but the research would be hilarious to watch.

Other potential braking technologies to be considered might include: a robust scoop on the plane that could be lowered into a trough filled with water, a runway graded steeply uphill at the end, and a truly moby version of the good old U.S. Navy standby, the cable trap.

$\endgroup$
-1
$\begingroup$

In my opinion , its an amazing idea to down the speed of an ground running aircraft to a big extend using eddy current braking. The main adavantage of this technology is that ,formation of eddycurrent can be done uniformly and hence it wont create irregular braking impact. Rather thinking about stoping the aircraft it is more relavent to think about reducing the speed within a short time period ,so that , shorter runways will be required for massive aircrafts to land.Hence for takeoff purpose only lenghty runways are required. And its will also make the pilots easy to face the impact of overshooting the runway during landing.

As we know that, there are many accidents taking place now a days in the time of landing (overshooting the runway),which makes the entire flight a bad memmory for the passengers. Like every part of flight , safe landing is also very important to ensure that the entire flight is not life challenging.So it is time to think about an effective braking system that makes the aeronautical industry more safe and less challenging like the "EDDY CURRENT BRAKING SYSTEM".

$\endgroup$
  • 7
    $\begingroup$ more braking will only lead to skidding and blown tires. The limit for today's aircraft brakes is the friction between wheel and ground. How the wheel is braked is less important and disk brakes are the most weight efficient solution. Also, it would be more helpful if you offer less opinion and more facts. $\endgroup$ – Peter Kämpf Sep 10 '17 at 17:29
  • 1
    $\begingroup$ When you quote, link (or cite if you only have paper form) the source. $\endgroup$ – Jan Hudec Sep 10 '17 at 20:53
  • $\begingroup$ @PeterKämpf: I thought the chief challenge for brakes were aborted take-offs due to the high weight. And it appears in those cases fire is a major problem (as you're converting all the kinetic energy into heat). Not that eddy current brakes would solve this, that's just another means of turning motion into heat. $\endgroup$ – MSalters Sep 11 '17 at 7:21
  • $\begingroup$ @MSalters: You're right, I was only thinking of regular landings where too much braking will destroy the tires. Same goes for aborted take-offs, too. $\endgroup$ – Peter Kämpf Sep 11 '17 at 15:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.