Now this is what you call a brake calliper unit!!

[podge]

Thought you might like to see this, it is a brake unit I fitted to a 747 this afternoon.You can see my hand on one of the 4 rotors(discs) and each one of these is braked by 2 brake discs of the same surface area(unlike car disc pads),all the brakeing areas are pure carbon fibre...they get very hot in service.Each unit has 8 pistons(3000psi), the whole assembly is VERY heavy...don't even ask the price! I had to change this unit as I spotted a siezed brake piston...even 747s have similar brake problems to our cars!As for retarding power, there are 16 such units to an aircraft, swept area...do the sums!!They are very VERY effective, so much so that most crew elect to land on auto-brake, a system that allows you to preselect up to 5 different rate of retardation.This is because if the brakes are applied too hard on landing there is a very real chance of structurally damageing the landing gear.Each wheel has antilock( a superb very sophisticated system),wheel temperature,brake torque applied,tyre pressure,and automatic tyre deflation if too hot and all these parameters(16 main wheels and 2 nose gear) can all be dislayed at once on the flight deck.I hope I have not bored you too much!!...if in the wrong Forum please move it and hope the picture loads after all this. Regards..P.