I have never realised that there were 2 'holes' at the very end of a B737. I assume that the biggest hole is the outlet for the APU, but what is the first, smaller hole for?
BTW, Very nice picture Lee!
Man's flight through life is sustained by the power of his knowledge.
Avioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11
Reply 1, posted (11 years 6 months 2 weeks 2 hours ago) and read 2295 times:
In the NG 737's the APU cooling air is provided by an eductor system. The air is drawn in by venturi (for lack of a better term) action and flows across the oil cooler and through the compartment before being extracted through a jacket surrounding the exhaust duct. The upper hole is the air inlet. (I might add that it is exactly the size prefered by the pigmy barn owl for its nest.)
Here's a link
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533