2H4
Topic Author
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

Very Strange PT-6 Exhaust

Tue Apr 24, 2007 8:52 am



So I ran across these photos of a Caravan:


View Large View Medium
Click here for bigger photo!

Photo © Michael Durning
View Large View Medium
Click here for bigger photo!

Photo © Peter Stuhlmann - CYOW Airport Watch



...and I can't figure out why the exhaust has been extended. Here's a shot of the same aircraft with the standard exhaust:


View Large View Medium
Click here for bigger photo!

Photo © Jean-Luc Poliquin



If anyone knows the purpose of this mod, I'd love to hear it.


2H4


Intentionally Left Blank
 
zanl188
Posts: 3443
Joined: Sat Oct 21, 2006 9:05 pm

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 8:58 am

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.
Legal considerations provided by: Dewey, Cheatum, and Howe
 
KELPkid
Posts: 5247
Joined: Wed Nov 02, 2005 5:33 am

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 9:07 am

Quoting ZANL188 (Reply 1):
or was being recirculated into the cabin thru what appears to be a large opening in the fuselage bottom.


 checkmark 

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?  confused 
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
 
lowrider
Posts: 2542
Joined: Wed Jun 30, 2004 3:09 am

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 9:14 am

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.
Proud OOTSK member
 
KELPkid
Posts: 5247
Joined: Wed Nov 02, 2005 5:33 am

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 9:22 am

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  Smile
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
 
2H4
Topic Author
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 9:29 am



Thanks for the input, guys. Good stuff.

Quoting KELPkid (Reply 2):
Did they get the plane from the department of fish & wildlife, who used it for re-stocking lakes and streams?

Actually, I think it was originally used for tactical flannel drops and Molson replenishment in remote locations.  Wink


2H4


Intentionally Left Blank
 
KELPkid
Posts: 5247
Joined: Wed Nov 02, 2005 5:33 am

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 9:33 am

Quoting 2H4 (Reply 5):
Actually, I think it was originally used for tactical flannel drops and Molson replenishment in remote locations. Wink


2H4

Or maybe it was the aircraft used to drop Dudley Dooright into the backwards-facing position on his faithful horse, Faithful Horse  duck 
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
 
N231YE
Posts: 2620
Joined: Tue Jul 25, 2006 9:24 am

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 9:34 am

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
Posts: 5247
Joined: Wed Nov 02, 2005 5:33 am

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 9:37 am

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 :-)
 
N231YE
Posts: 2620
Joined: Tue Jul 25, 2006 9:24 am

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 9:43 am

Quoting KELPkid (Reply 8):
Do the Mounties (Royal Canadian Mounted Police) regularly engage in aerial photography?

Maybe to make sure that the United States military isn't secretly mobilizing to invade Canada?  mischievous 
 
zanl188
Posts: 3443
Joined: Sat Oct 21, 2006 9:05 pm

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 9:53 am

Quoting KELPkid (Reply 2):
I wonder why the Mounties need a large trap door in the floor?

Maybe...

A large format camera..

Lidar

Mysterious WMD sensor
Legal considerations provided by: Dewey, Cheatum, and Howe
 
KELPkid
Posts: 5247
Joined: Wed Nov 02, 2005 5:33 am

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 10:06 am

Quoting ZANL188 (Reply 10):

Mysterious WMD sensor

Or the deployment thereof...  Wink Maybe it's for the planned Canadian invasion of the USA (and we're not talking Celene Dion or Rick Moranis here...)  Smile
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
 
zanl188
Posts: 3443
Joined: Sat Oct 21, 2006 9:05 pm

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 10:38 am

Quoting KELPkid (Reply 11):
planned

"planned"? Alex Trebek, Paul Shafer, and William Shatner are already here...  Smile
Legal considerations provided by: Dewey, Cheatum, and Howe
 
USCGC130
Posts: 201
Joined: Sun Apr 22, 2007 8:30 am

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 10:45 am

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
Posts: 2542
Joined: Wed Jun 30, 2004 3:09 am

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 12:06 pm

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...
Proud OOTSK member
 
2H4
Topic Author
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 12:11 pm




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.

That's great.  biggrin 


2H4


Intentionally Left Blank
 
L-188
Posts: 29881
Joined: Wed Jul 07, 1999 11:27 am

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 12:20 pm

Quoting 2H4 (Reply 15):
The Piper Cheyenne 400 and Casa C-212 have rear-mounted exhaust.

Both those aircraft are also powered by TPE-331's not PT-6's.

As far as the pipe, don't know but I bet it works great for keeping soot stains off the airplane.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
 
2H4
Topic Author
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 12:41 pm




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.


2H4


Intentionally Left Blank
 
User avatar
zeke
Posts: 9849
Joined: Thu Dec 14, 2006 1:42 pm

RE: Very Strange PT-6 Exhaust

Tue Apr 24, 2007 8:48 pm

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.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
KELPkid
Posts: 5247
Joined: Wed Nov 02, 2005 5:33 am

RE: Very Strange PT-6 Exhaust

Wed Apr 25, 2007 9:51 am

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 Big grin

Beaut, eh?  Wink My apologies to the forum members from the Great White North...
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
 
lowrider
Posts: 2542
Joined: Wed Jun 30, 2004 3:09 am

RE: Very Strange PT-6 Exhaust

Wed Apr 25, 2007 1:08 pm

Quoting KELPkid (Reply 19):
Beaut, eh?

Careful, the punishment for such offenses is death, by Celine Dion.
Proud OOTSK member
 
LJ35
Posts: 17
Joined: Thu Nov 23, 2006 2:08 am

RE: Very Strange PT-6 Exhaust

Wed Apr 25, 2007 5:46 pm

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
Posts: 5247
Joined: Wed Nov 02, 2005 5:33 am

RE: Very Strange PT-6 Exhaust

Thu Apr 26, 2007 12:13 am

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?  Smile
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
 
airfoilsguy
Posts: 3485
Joined: Sun Oct 09, 2005 7:28 am

RE: Very Strange PT-6 Exhaust

Thu Apr 26, 2007 4:10 am

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.
It's not a near miss it's a near hit!!
 
Fly2HMO
Posts: 7207
Joined: Sat Jan 24, 2004 12:14 pm

RE: Very Strange PT-6 Exhaust

Thu Apr 26, 2007 11:16 am

OK guys seriously you're all thinking WAY too deep into this.  sarcastic 

That's the test plane Flowmaster just started using for inflight tests for their new aircraft sport exhaust line. Big grin

 duck 
 
2H4
Topic Author
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Very Strange PT-6 Exhaust

Thu Apr 26, 2007 12:24 pm




Quoting FLY2HMO (Reply 24):
That's the test plane Flowmaster just started using for inflight tests for their new aircraft sport exhaust line.

Not shown are the "Trucknutz" hanging between the gear legs:










2H4


Intentionally Left Blank

Who is online

Users browsing this forum: No registered users and 18 guests