Originally Posted by
JamesNoBrakes
Haha,remember using one on a cold morning and noting after a few min that there was no heat. Looked to my right and noticed it was pouring fuel all over the ramp out the exhaust. I think I got lucky on that one, if it ignited it would have been messy. Otherwise, they usually work damn well and it's nearly instant heat. I think we used similar ones in the army running off of jp5 or something, THOSE never worked, but the aviation ones I've used have worked well.
Janitrols are located in the nose and I doubt that one could light off without at least one engine running. But it is an excellent systems question for an exam and I'll check on it. They also have thermocouples to prevent fuel flow to the unit in the absence of exhaust heat.