Northwest727 From United States of America, joined Jul 2005, 491 posts, RR: 0 Posted (3 years 1 month 1 week 1 day 9 hours ago) and read 4550 times:
I noticed on a King Air 350 recently, that around both exhaust stacks on both engines, had some sort of "devices." These appear to be some kind of aftermarket retrofit, consisting of "strakes"...I assume some kind of vortex generators. I've never seen this on any other PT6A powered aircraft. What are the purpose of these exhaust devices? Some kind of performance enhancement?
I was able to trace the tail number and found some pictures of the aircraft online. I cropped out the right side engine to show these devices here:
T prop From United States of America, joined Apr 2001, 1032 posts, RR: 1
Reply 1, posted (3 years 1 month 1 week 1 day 4 hours ago) and read 4422 times:
I've installed those on a King Air, they're part of a kit from Raisbeck Engineering. If I remember, the ones in the picture besides helping with low speed performance, also keep exhaust soot from blackening the rear part of the nacelle.
nws2002 From United States of America, joined Feb 2008, 1032 posts, RR: 0
Reply 2, posted (3 years 1 month 1 week 1 day 4 hours ago) and read 4419 times:
I think they are Raisbeck composite exhaust stack fairings .
Here's a description from the website:
"Small composite fairings over fronts of exhaust stacks on all P&WC PT6A-powered Beechcraft King Air and Super King Air models; prevent power loss from hot air entering forward cowling and engine inlet and reduce drag by streamlining propeller wake; fairing held in place by camlocks; two 'delta-wing' vortex generators on fairings divert high-energy gases between exhaust and cowling, keeping exhaust soot from accumulating on nacelle and wing."