Re: Straight exhaust stacks on Rangers.

[hotfoot49]

'I'm not an expert on the subject but over the years I have been told that a straight pipe might cause the exhaust valves to warp or burn due to lack of some back pressure. I knew a guy who had straight stacks on a Ranger but they had a little curve to them at the end. That's my 2 cents for what it's worth.

Mike Kelly
Fairchild Club'

[Airy Millet]

'we got angle cuts at the pipe end!



To: fairchildclub@yahoogroups.com
From: hotfoot49@hotmail.com
Date: Tue, 30 Nov 2010 20:50:32 +0000
Subject: [fairchildclub] Straight exhaust stacks on Rangers.






I'm not an expert on the subject but over the years I have been told that a straight pipe might cause the exhaust valves to warp or burn due to lack of some back pressure. I knew a guy who had straight stacks on a Ranger but they had a little curve to them at the end. That's my 2 cents for what it's worth.

Mike Kelly
Fairchild Club





[Non-text portions of this message have been removed]'

[William Creighton]

'Mike,

Thanks for weighing in. Haven't discovered if there's a 337 out there for the single-stacks yet? Having AMI fab new 3-1 pipes in ss as replacements.

Even less an expert, but understand that the backpressure would be useful (when properly tuned) to increase cylinder scavaging, which improves cylinder filling/power delivery. Never heard the exhaust valve concerns raised in this regard.

Bill C.



To: fairchildclub@yahoogroups.com
From: hotfoot49@hotmail.com
Date: Tue, 30 Nov 2010 20:50:32 +0000
Subject: [fairchildclub] Straight exhaust stacks on Rangers.






I'm not an expert on the subject but over the years I have been told that a straight pipe might cause the exhaust valves to warp or burn due to lack of some back pressure. I knew a guy who had straight stacks on a Ranger but they had a little curve to them at the end. That's my 2 cents for what it's worth.

Mike Kelly
Fairchild Club





[Non-text portions of this message have been removed]'

[Airy Millet]

'

> Even less an expert, but understand that the backpressure would be useful (when properly tuned) to increase cylinder scavaging, which improves cylinder filling/power delivery. Never heard the exhaust valve concerns raised in this regard.
>

important in the 3-in-1 design is the conical shape of the receiver tube! in order to have the right tune at the cruise rpm!
(as the inter-cylinder pitch is fixed, the speed of exhaust gases is only modified by the expansion alo,g the tubing).

[Non-text portions of this message have been removed]'

[BO]

'Hello all

Just a note. Back in the early fifty s when I had my PT 26 I
considered short stacks.

One day I asked a ground crew why he was in such a hurry to put the
plugs in the exhaust holes on our F 51s and he told me it was to keep
the ex valves from fast cooling and prevent warp. Just info.

We gotta keep rebuilding em to keep our history alive. Keep up the good
work all.

BO

On 11/30/2010 4:02 PM, Airy Millet wrote:
> we got angle cuts at the pipe end!
>
>
>
> To: fairchildclub@yahoogroups.com
> From: hotfoot49@hotmail.com
> Date: Tue, 30 Nov 2010 20:50:32 +0000
> Subject: [fairchildclub] Straight exhaust stacks on Rangers.
>
>
>
>
>
>
> I'm not an expert on the subject but over the years I have been told that a straight pipe might cause the exhaust valves to warp or burn due to lack of some back pressure. I knew a guy who had straight stacks on a Ranger but they had a little curve to them at the end. That's my 2 cents for what it's worth.
>
> Mike Kelly
> Fairchild Club
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>
>

'

[BOB DUNN]

'Bill, This from a man who headed up a repair depot for ranger engines during WWll. He ran a private airport in Seagoville, Texas & was the man I went to for info until he passed away. He was very opposed to straight stacks. His explanation was many of those already aired. The Ranger stacks were purpose designed to give the proper back pressure & prevent all the engine maladies already posted. The designed stacks were more expensive & required more time to fabricate so if straight stacks had been O.K. they would have been used if only to save time.

--- On Tue, 11/30/10, William Creighton wrote:

> From: William Creighton
> Subject: RE: [fairchildclub] Straight exhaust stacks on Rangers.
> To: fairchildclub@yahoogroups.com
> Date: Tuesday, November 30, 2010, 3:48 PM
>
> Mike,
>
> Thanks for weighing in.  Haven't discovered if there's
> a 337 out there for the single-stacks yet?  Having AMI
> fab new 3-1 pipes in ss as replacements.
>
> Even less an expert, but understand that the backpressure
> would be useful (when properly tuned) to increase cylinder
> scavaging, which improves cylinder filling/power
> delivery.  Never heard the exhaust valve concerns
> raised in this regard.
>
> Bill C.
>
>
>
> To: fairchildclub@yahoogroups.com
> From: hotfoot49@hotmail.com
> Date: Tue, 30 Nov 2010 20:50:32 +0000
> Subject: [fairchildclub] Straight exhaust stacks on
> Rangers.
>
>
>  
>
>
>
> I'm not an expert on the subject but over the years I have
> been told that a straight pipe might cause the exhaust
> valves to warp or burn due to lack of some back pressure. I
> knew a guy who had straight stacks on a Ranger but they had
> a little curve to them at the end. That's my 2 cents for
> what it's worth.
>
> Mike Kelly
> Fairchild Club
>
>
>
>    
>         
>           
>  
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>     fairchildclub-fullfeatured@yahoogroups.com
>
>
>

'

[Airy Millet]

'of course!

and I could add that having exhaust stacks is better than single pipes, in case of nuts going loose during flight...as you may loose one pipe, but not a full stack!!

))

(power output, sound level, engine roughness should be slightly better with exhaust stacks and reliability as well).
(but single pipes are so easy to fabricate and weld yourself...and cheaper....but you get what you buy).
Airy



To: fairchildclub@yahoogroups.com
From: bobaviator@yahoo.com
Date: Wed, 1 Dec 2010 06:07:15 -0800
Subject: RE: [fairchildclub] Straight exhaust stacks on Rangers.






Bill, This from a man who headed up a repair depot for ranger engines during WWll. He ran a private airport in Seagoville, Texas & was the man I went to for info until he passed away. He was very opposed to straight stacks. His explanation was many of those already aired. The Ranger stacks were purpose designed to give the proper back pressure & prevent all the engine maladies already posted. The designed stacks were more expensive & required more time to fabricate so if straight stacks had been O.K. they would have been used if only to save time.

--- On Tue, 11/30/10, William Creighton wrote:

> From: William Creighton
> Subject: RE: [fairchildclub] Straight exhaust stacks on Rangers.
> To: fairchildclub@yahoogroups.com
> Date: Tuesday, November 30, 2010, 3:48 PM
>
> Mike,
>
> Thanks for weighing in. Haven't discovered if there's
> a 337 out there for the single-stacks yet? Having AMI
> fab new 3-1 pipes in ss as replacements.
>
> Even less an expert, but understand that the backpressure
> would be useful (when properly tuned) to increase cylinder
> scavaging, which improves cylinder filling/power
> delivery. Never heard the exhaust valve concerns
> raised in this regard.
>
> Bill C.
>
>
>
> To: fairchildclub@yahoogroups.com
> From: hotfoot49@hotmail.com
> Date: Tue, 30 Nov 2010 20:50:32 +0000
> Subject: [fairchildclub] Straight exhaust stacks on
> Rangers.
>
>
>
>
>
>
> I'm not an expert on the subject but over the years I have
> been told that a straight pipe might cause the exhaust
> valves to warp or burn due to lack of some back pressure. I
> knew a guy who had straight stacks on a Ranger but they had
> a little curve to them at the end. That's my 2 cents for
> what it's worth.
>
> Mike Kelly
> Fairchild Club
>
>
>
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
> fairchildclub-fullfeatured@yahoogroups.com
>
>
>





[Non-text portions of this message have been removed]

'

[Craig]

'Just to muddy the waters a bit, the Ranger VL-770 as used in my AT-21 and in the Seamew seaplane, ran individual stacks.. When I get mine restored and in the air, it ought to sound pretty wild with a pair of 770's and 24 short stacks in full song.

Craig C.





[Non-text portions of this message have been removed]'

[Don Harvie]

'On 1/12/2010 7:50 AM, hotfoot49 wrote:

> I'm not an expert on the subject but over the years I have been told that a straight pipe might cause the exhaust valves to warp or burn due to lack of some back pressure. I knew a guy who had straight stacks on a Ranger but they had a little curve to them at the end. That's my 2 cents for what it's worth.
>
> Mike Kelly
> Fairchild Club

Hi All,

I'm not Fairchild owner & just lurk here, but thought I'd add my 2bits
on this.

A few years back my Dad had an engine failure in an Auster. This
aircraft has an inverted 4cyl Gypsy. The cause of the engine failure was
the exhaust valve head separating from the valve stem.

One of the observations made during the subsequent major overhaul, by
the Gypsy guru here in Aus was that the short straight stacks were not
good for the exhaust valves due to lack of backpressure. Whether that
was a contributor to the failure I don't know.

I think there is also something about replacing exhaust valves on the
Gypsy every 400 hours, and the failure occurred on No.2 Cyl which is
also the hottest in that engine. We don't know how many hours that valve
had been in service, but we suspected it might have been more than 400.

The aircraft is still flying with the single exhaust per cylinder as are
a number of other Auster's in Aus.

Don H
Sydney, Aus'