Exhaust in the Cockpit?

j ferguson · 8 July 2008, 05:32 AM

Looking at the nice stacks on Koloman's Albatross made me wonder if exhaust in the cockpit can be a problem. With those long stacks and the prop rotation, I would think that he won't have a problem, but what about port-side exhausts? It looks as though the Hisso powered planes use exhaust pipes to get the the discharge point behind the cockpit.

Is there any experience with this problem; if it indeed is a problem?

John

Ransom E. Olds · 8 July 2008, 07:38 AM

The Hiero engines much-used in the Austro-Hungarian air service had stubby exhaust stacks on the left-hand side and apparently were found acceptable. Ransom

j ferguson · 8 July 2008, 08:21 AM

Quote:

Originally Posted by Ransom E. Olds

The Hiero engines much-used in the Austro-Hungarian air service had stubby exhaust stacks on the left-hand side and apparently were found acceptable. Ransom

Same prop rotation?

Ransom E. Olds · 8 July 2008, 08:43 AM

John: I was afraid you'd ask about rotation. Don't know, really, but Austrian aircraft had engines that exhausted on either right or left and it seems reasonable (to me at least) that prop rotation was uniform in all engine types. Maybe someone can answer this one. Ransom

j ferguson · 8 July 2008, 09:03 AM

Quote:

Originally Posted by Ransom E. Olds

John: I was afraid you'd ask about rotation. Don't know, really, but Austrian aircraft had engines that exhausted on either right or left and it seems reasonable (to me at least) that prop rotation was uniform in all engine types. Maybe someone can answer this one. Ransom

This may be a spurious concern because of the breeziness of these open cockpits. I think we're only talking about inline engines, in any case, and it does make you wonder why some installations have simple straight stacks and others have collectors and pipes.

thanks, john

Dan_San_Abbott · 9 July 2008, 10:11 AM

Gentlemen:
Almost all German an Austrian aircraft had no firewall with in-line engines. Any damage to the exhaust system would have exhaust leakage into the cockpit as well.
Blue skies,
Dan-San

j ferguson · 9 July 2008, 10:26 AM

thanks, Dan, for the note. I was astonished about not having firewalls. When we were looking at Spadmaker's build it looked like there wasn't going to be a firewall, which I thought was a bit dicey.

I guess they felt that these planes were like motorcycles.

I think you might assume that without a firewall, the airflow in the cockpit would be mostly out and that there would be enough turbulence for that reason that there couldn't be any eddies with exhaust fumes in them.

It must have been a problem on some German planes with in-line engines because you sometimes see the stacks fed to a vertical stack to get the discharge over the wing. This seems ( I could be wrong, here) mostly 2 seaters. Maybe the problem was in the second seat.

My only open-cockpit time was in a Stearman and I can't remember any fume issue.

best regards, John

j ferguson · 9 July 2008, 12:04 PM

Such as:

http://www.theaerodrome.com/forum/at...1&d=1215633800

or
http://www.theaerodrome.com/forum/at...1&d=1215633868

btw, how do I make these url's invisible?

brisfitworks · 10 July 2008, 04:47 AM

Concerns about breathing exhaust may be exagerated.

Obviously, all rotary pilots suffered this, to some extent.

Lots of variations in pipe design between aircraft and between issues of any type over its design life says there was something up. Noise and flame suppression are two know causes of change. German exhausts definitely seem to be conscious of the prop's swirling of the exhaust around the fuse, but...

I know from standing up in our Strutter, during the first airshow, that we didn't even know we had a very significant exhaust leak in our collector ring until we hit the smoke system - the smoke flooded out the top cooling vents and made the everything disappear and we went IFR for those few seconds. That was even for me in the back standing up!

There is so much airflow in the cockpits we didn't smell the exhaust leak!

Quote:

Originally Posted by j ferguson

This may be a spurious concern because of the breeziness of these open cockpits.
thanks, john

Joe Perkel · 10 July 2008, 05:12 AM

Quote:

Originally Posted by brisfitworks

Concerns about breathing exhaust may be exagerated.

Obviously, all rotary pilots suffered this, to some extent.

Lots of variations in pipe design between aircraft and between issues of any type over its design life says there was something up. Noise and flame suppression are two know causes of change. German exhausts definitely seem to be conscious of the prop's swirling of the exhaust around the fuse, but...

I know from standing up in our Strutter, during the first airshow, that we didn't even know we had a very significant exhaust leak in our collector ring until we hit the smoke system - the smoke flooded out the top cooling vents and made the everything disappear and we went IFR for those few seconds. That was even for me in the back standing up!

There is so much airflow in the cockpits we didn't smell the exhaust leak!

For reference sake, normal background CO in the atmosphere is 0.1 PPM. Symptoms appear @ 35 PPM with a slight headache @ 6-8 hours continuous exposure. Immediate unconsciousness with 2- 3 breaths requires 12,800 PPM.

It's a viable concern in an enclosed cockpit however, that having been said, fatalities have occurred in an open air environment with a boating activity called, "transom surfing." I suspect, a freak set of circumstances on a hot still day while on the ground, could possibly duplicate this.