ZANL188 From United States of America, joined Oct 2006, 3247 posts, RR: 0 Reply 1, posted (6 years 4 weeks ago) and read 3012 times:
I'll hazard a guess and say the exhaust was interfering with a sensor or was being recirculated into the cabin thru what appears to be a large opening in the fuselage bottom.
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KELPkid From United States of America, joined Nov 2005, 5929 posts, RR: 4 Reply 2, posted (6 years 4 weeks ago) and read 3006 times:
Quoting ZANL188 (Reply 1): or was being recirculated into the cabin thru what appears to be a large opening in the fuselage bottom.
I'll second that vote...I wonder why the Mounties need a large trap door in the floor? Did they get the plane from the department of fish & wildlife, who used it for re-stocking lakes and streams?
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Lowrider From United States of America, joined Jun 2004, 3220 posts, RR: 11 Reply 3, posted (6 years 4 weeks ago) and read 2997 times:
Quoting ZANL188 (Reply 1): I'll hazard a guess and say the exhaust was interfering with a sensor or was being recirculated into the cabin thru what appears to be a large opening in the fuselage bottom.
Since this is the case in other aircraft, I assume it is here, too. All that hot exhaust could screw up an IR picture.
KELPkid From United States of America, joined Nov 2005, 5929 posts, RR: 4 Reply 4, posted (6 years 4 weeks ago) and read 2986 times:
Quoting Lowrider (Reply 3): Since this is the case in other aircraft, I assume it is here, too. All that hot exhaust could screw up an IR picture.
However, most law enforcement aircraft that I've seen equipped with a FLIR (Forward-looking Infrared) system use a pod with a dome that houses a camera that swivels on a gimbal...sure it knocks a few knots off the top cruise, but it works. I wonder if that's what's behind trapdoor #1
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N231YE From , joined Dec 1969, posts, RR: Reply 7, posted (6 years 3 weeks 6 days 23 hours ago) and read 2973 times:
Could be for an aerial photography company (exhaust gasses produce that "heat blur," a no-no in professional photographs of the ground).
There is an aerial-photography company based at my university's airport, and all of their C172's have a weird looking exhaust stack extension that empties at the pilot's side of the a/c, further than the rear window.
Tomorrow, when I am out at the flight line, I will try to get a photo of one of these aircraft.
KELPkid From United States of America, joined Nov 2005, 5929 posts, RR: 4 Reply 8, posted (6 years 3 weeks 6 days 23 hours ago) and read 2973 times:
Quoting N231YE (Reply 7): Could be for an aerial photography company (exhaust gasses produce that "heat blur," a no-no in professional photographs of the ground).
Do the Mounties (Royal Canadian Mounted Police) regularly engage in aerial photography?
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
Uscgc130 From , joined Dec 1969, posts, RR: Reply 13, posted (6 years 3 weeks 6 days 22 hours ago) and read 2923 times:
Is the Caravan the only PT6-powered aircraft that uses an under-fuselage exhaust instead of those lateral "horns," as on King Airs and T-34Cs?
I read an article in one of the avgeek magazines a year or so ago about the owner of a gorgeous Caravan on amphibious floats, and how he uses the plane for both business and pleasure. The Caravan's exhaust is mounted at a slight angle, and he takes advantage of this when taxiing up to a dock. He'll place the prop in flat pitch and wind up the engine; the thrust from the exhaust will provide enough of a lateral vector to move the plane sideways to the left. Nifty.
Lowrider From United States of America, joined Jun 2004, 3220 posts, RR: 11 Reply 14, posted (6 years 3 weeks 6 days 21 hours ago) and read 2898 times:
Quoting KELPkid (Reply 4): However, most law enforcement aircraft that I've seen equipped with a FLIR (Forward-looking Infrared) system use a pod with a dome that houses a camera that swivels on a gimbal...sure it knocks a few knots off the top cruise, but it works.
That works great for tactical "live" situations, but developing a large scale IR map of an area has its uses. For example it is one method to locate drug operations.
Quoting 2H4 (Reply 5): Actually, I think it was originally used for tactical flannel drops and Molson replenishment in remote locations.
You know, if we went up there and got cases of the good Molson, then drop it after we cross the border, before we clear customs, and use a GPS to go back to it later...
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 15, posted (6 years 3 weeks 6 days 21 hours ago) and read 2897 times:
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Quoting Uscgc130 (Reply 13): Is the Caravan the only PT6-powered aircraft that uses an under-fuselage exhaust instead of those lateral "horns," as on King Airs and T-34Cs?
With the obvious exception of helicopters, I think that's correct. The Dash-7 and Basler BT-67 have exhaust mounted on top of the nacelles. The Piper Cheyenne 400 and Casa C-212 have rear-mounted exhaust. The Caravan, however, appears to be the only one that utilizes a single under-fuselage exhaust.
Quoting Uscgc130 (Reply 13): He'll place the prop in flat pitch and wind up the engine; the thrust from the exhaust will provide enough of a lateral vector to move the plane sideways to the left.
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 17, posted (6 years 3 weeks 6 days 20 hours ago) and read 2882 times:
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Quoting L-188 (Reply 16): Both those aircraft are also powered by TPE-331's not PT-6's.
Blast. You're right. I was thinking of the -300P variant of the 212, which has the PT6A-65s, and I think I got the Cheyenne III and 400 mixed up. Clearly, it's time for bed.
Zeke From Hong Kong, joined Dec 2006, 7725 posts, RR: 73 Reply 18, posted (6 years 3 weeks 6 days 12 hours ago) and read 2806 times:
Quoting Lowrider (Reply 14):
That works great for tactical "live" situations, but developing a large scale IR map of an area has its uses. For example it is one method to locate drug operations.
Exactly what is would be for, IR photos are good for finding drugs in a forest or for taking high altitude photos of a fire.
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KELPkid From United States of America, joined Nov 2005, 5929 posts, RR: 4 Reply 19, posted (6 years 3 weeks 5 days 23 hours ago) and read 2655 times:
Quoting Lowrider (Reply 14): You know, if we went up there and got cases of the good Molson, then drop it after we cross the border, before we clear customs, and use a GPS to go back to it later...
Yeah, then we could call you D. "Beer" Cooper
Beaut, eh? My apologies to the forum members from the Great White North...
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
Lowrider From United States of America, joined Jun 2004, 3220 posts, RR: 11 Reply 20, posted (6 years 3 weeks 5 days 20 hours ago) and read 2604 times:
LJ35 From Canada, joined Nov 2006, 21 posts, RR: 0 Reply 21, posted (6 years 3 weeks 5 days 15 hours ago) and read 2574 times:
To answer 2H4's question,the extended exhaust pipe is only mounted on this plane when the FLIR is in place.If you look at the first photo attached(select the large format)the FLIR is mounted underneath the port wing directly on the "U" in the aircraft registration(it is black in colour).In case your wondering why I know this,I fuel this aircraft on a daily basis given that it is based at CYOW(Ottawa,Ontario).The other cool thing about this Caravan and the other 2 that the RCMP operate is that they are configured for single point refuelling in addition to the standard overwing method.The single point hook-up is located port side right behind the main gear.Interesting fact about the single point fuelling system on this aircraft is that it won't completely fill the tanks(about an hour's less flying time when fully fuelled via the single point method).This system has been a godsend when they show up with their amphib caravan once in a while.
KELPkid From United States of America, joined Nov 2005, 5929 posts, RR: 4 Reply 22, posted (6 years 3 weeks 5 days 9 hours ago) and read 2529 times:
Quoting LJ35 (Reply 21): To answer 2H4's question,the extended exhaust pipe is only mounted on this plane when the FLIR is in place.If you look at the first photo attached(select the large format)the FLIR is mounted underneath the port wing directly on the "U" in the aircraft registration(it is black in colour).
Do you know anything about the mysterious trap door on the bottom of the fuselage, and why that's there?
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Airfoilsguy From , joined Dec 1969, posts, RR: Reply 23, posted (6 years 3 weeks 5 days 5 hours ago) and read 2478 times:
Would the extension cut down on some of the noise inside the cabin? Also, what kind of performance penaltys does this aircraft experience when the extension is mounted.
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