If I remember correctly, to start up old fighters such as F-4s, you need an ASU but it looks new fighters do not need an ASU. Today, I was watching this video. It's a so cool video to know how new fighters start their engines. From 2:38, something starts and make a sound just like woooooooooooooooooo... you think a wolf is howling. From 3:06, the sound becomes stronger but, the question is what kind of starter is used by P&W F100 that makes such a sound?

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    $\begingroup$ Well, the F-4 normally used an Auxiliary Power Unit, APU (or ASU as you call it), but it also had the capability to use *Start Cartridges" which were pyrotechnic cartridges the size/shape of a gallon can that were inserted into slots in the auxiliary air doors, and when fired, produced high pressure gas to drive a turbine that rotated the engine fast enough to get it started.. But they were prone to misfire and so were used infrequently. $\endgroup$ Jul 9, 2021 at 12:51
  • $\begingroup$ @CharlesBretana That sounds like an answer! $\endgroup$
    – 0scar
    Jul 12, 2021 at 9:14
  • $\begingroup$ Except that it doesn't speak to how F-15s and F-16s do it, which, I think, (but don't know for sure), is because they have an internal APU. $\endgroup$ Jul 12, 2021 at 13:06

1 Answer 1


Aha! finally found the answer. Based on this and this F-15 uses an APU named Jet Fuel Starter (JFS) which is fitted centrally between the two engines. See 15 on the figure below

Position of JFS

Another figure of the intake and exhaust of the JFS from bottom of the fighter:

JFS from bottom of the fighter

The below figure shows the danger area of the JFS:

the danger area of the JFS

And finally here is an image of this JFS:

enter image description here

Hope this helps.


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