Strantor inspired post...

WBahn

Joined Mar 31, 2012
24,700
So they do what in the air now? o_O

Having been developed for craft that work in near frictionless environments is that why they don't work so well on the ground with machines that actually need to stop in a specific distance before crashing into something? :oops:
They were developed for aircraft because of the desire to takeoff and land in shorter distances on questionable surfaces. They were first developed in 1929 and by the late sixties nearly all large or fast aircraft used them. On the F-15, for instance, if you lose utility hydraulics you still have the JFS bottles that can provide hydraulics to the brakes, but you do not have ABS capabilities. As a result, any pilot that loses the utility hydraulics (Utility-A, IIRC) is extremely hesitant to land where they will have to use the brakes because it is very difficult to keep the plane on the runway and a high-speed departure off the side of a runway seldom ends well. So the preferred method is to divert, if possible, to a field that has arresting gear or other barricade equipment.
 

cmartinez

Joined Jan 17, 2007
6,469
They were developed for aircraft because of the desire to takeoff and land in shorter distances on questionable surfaces. They were first developed in 1929 and by the late sixties nearly all large or fast aircraft used them. On the F-15, for instance, if you lose utility hydraulics you still have the JFS bottles that can provide hydraulics to the brakes, but you do not have ABS capabilities. As a result, any pilot that loses the utility hydraulics (Utility-A, IIRC) is extremely hesitant to land where they will have to use the brakes because it is very difficult to keep the plane on the runway and a high-speed departure off the side of a runway seldom ends well. So the preferred method is to divert, if possible, to a field that has arresting gear or other barricade equipment.
:eek: 1929!
That was waaaaayyyy before electronics got involved in aircraft control...
How where they able to sense and control it? Hydraulics, pneumatics?
 

WBahn

Joined Mar 31, 2012
24,700
:eek: 1929!
That was waaaaayyyy before electronics got involved in aircraft control...
How where they able to sense and control it? Hydraulics, pneumatics?
They used a drum and flywheel system in which the speed of the drum (mounted on the wheel) was compared to the speed of the flywheel (which, I'm assuming, was air driven) and if the drum was rotating more slowly than the flywheel a valve would open reducing the pressure to the brakes. As primitive as this system was, landing distances were reduced by about 1/3 and flat-spotted tires were virtually eliminated.

It's actually quite amazing how many quite sophisticated things were done in the days before electronics.
 

#12

Joined Nov 30, 2010
18,076
It's actually quite amazing how many quite sophisticated things were done in the days before electronics.
That's part of what frustrates me about the Arduino Effect. Nobody tries to do clever or elegant designs, they just start on the logic diagram for a microprocessor program.

Right now, my central air conditioner is running on a board with 2 relays and a microprocessor. I can replace all its functions with 2 relays and 2 time delay circuits which can be done 3 different ways (designed around J201 j-fets, 555 timers, or old, Klixon style time delay relays). The only differences are that their board requires more space and is not repairable. Guess what I'm going to replace it with when it fails. :rolleyes:
 

BR-549

Joined Sep 22, 2013
4,936
Post #4.............so Euclid proved that X3 + Y3 = Z3.

Interesting.

So what was Fermat’s theorem?

I guess I mis-understood.

Is there anyone here who could state Fermat’s theorem for me?
 

BR-549

Joined Sep 22, 2013
4,936
That’s what I thought. So the #4 post............Euclid proved that X3 + Y3 is not equal to Z3,..........which proves Fermat was right.

Ok, thanks.

I believe Fermat proved that there are only 3 physical dimensions.

When n=2, you use all of them. If we had more dimensions, then n could equal 3.

I’m sure he knew that, and I’m sure his solution was simple.
 
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