Fuse Plugs and Hot Brakes.
This thread has shown that there are a few potentially dangerous myths and misunderstandings floating around concerning aircraft brakes and their limitations in being able to transform enormous amounts of kinetic energy into thermal energy and then dissipate that thermal/heat energy over time.
As stated earlier - ignore the energy already stored in overly hot brake packs, then follow with an aborted take off and I hope you can walk away from the heap off the end.
How many know the XXX millions of ft pnds of energy absorption capability designed into YOUR brakes.?
How many know the melt temperature of YOUR fuse plugs or even whether they are in your wheels.?
Please someone who knows give us a typical listing for a few heavies.
Here is one medium heavy out of the memory bank. F-111 brakes at 15 degrees C are designed to absorb 147 million ft pnds.
But it gets to be a bit complicated if you need to interpolate for a higher temperature start point than 15 degrees C. To enable these calculations you need to know the maximum design end temperature. The modern carbon disk brake pack apparently starts to go pear shaped around 1,000 degrees C
Knowing the numbers gives you the key to calculating how much you have left with brake pack temperatures above 15 C.
As an ageing TP, I seem to recall a figure of around 300,000,000+ ft pnds for a Valiant having 4 brake packs. Did an AUW full braking stop employing the old maxaret antiskid from a ground speed calculated to prove the design specs. Blew two tyres near the end of the roll out as two wheels locked up. Much smoke for 15 minutes or so as firecrew gingerly applied dry powder fire suppressant. Later examination of the disassembled brake units showed the extreme distress of most components. The disks were thick copper heavily chromium plated. Don't remember the peak temperatures reached but around 800 degrees would be a good guess..
Accelerate-stop testing is known by TPs to be extremely hazardous.