Where is the APU in the case of an S-duct (like the L-1011)? This question asks about the S-duct of the L-1011 Tristar. Fooot's answer shows a cut-out of the L-1011. Looking at this cut-out, I'm wondering:
If the engine is at the 'normal' location of the APU, where did the designers of the L-1011 put the APU?
I did a search, and found this site which mentions

The APU is located in a compartment in the aft fuselage.

Another site mentions

Its still in the &quot;tail&quot;. Its mounted below the #2 engine. Just forward of the tail skid.

But I don't see how you could fit the APU in the small available space.
(Source via aircraft.wikia.com)

APU is number 134 on the cutaway, which you can find near root of left stabilator leading edge. It is ahead of the engine, below the intake duct, on the left side.

By Reedy (Own work) [CC BY-SA 3.0], via Wikimedia Commons

Its exhaust is on the right side close to the stabilator's leading edge.