Today's Message Index:
----------------------
1. 09:51 AM - Re: Re:Crossover exhaust. (n223b@comcast.net)
2. 10:50 AM - Re: Re:Crossover exhaust. (LessDragProd@aol.com)
3. 02:04 PM - Re: Re:Crossover exhaust. (Hans Teijgeler)
4. 02:05 PM - Re: Re:Crossover exhaust. (Hans Teijgeler)
5. 03:20 PM - Re: Re:Crossover exhaust. (LessDragProd@AOL.COM)
6. 04:00 PM - Re: Re:Crossover exhaust. (Archie)
7. 09:18 PM - Re: Re:Crossover exhaust. (Fiveonepw@aol.com)
Message 1
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| Subject: | Re:Crossover exhaust. |
--> Engines-List message posted by: n223b@comcast.net
Dean,
Generally, the air temp under your engine indicates the effectivness of your baffeling.
Higher temps mean that the air is removing the heat from your engine.
It is highly unlikely that the air that has passed over your engine will ever
get hot enough to do any damage. What does create local temps sufficient to
do harm is the radiant energy from 1600 F. exhaust pipes that are glowing cherry
red. Heat shields are very effective at blocking this radiation from heating
less robust components under the cowl. A thin stainless steel shield between
your crossover pipes and oil sump will keep the heat produced by radiation
from exhaust pipes out of the oil. As I recall, Tony Bingless treats this subject
in his "Firewell Forward" book and shows some examples. Also, you can
get some ideas from other homebuild airplanes. I don't believe I've even seen
one that didn't have heat shields in several locations under the cowl.
Bob
-------------- Original message --------------
> --> Engines-List message posted by: "DEAN PSIROPOULOS"
>
>
>
> Thanks for the explanations everyone:
>
> That does make sense to me (about the power pulses and scavenging). I don't
> know where my Lancair buddy got his info but we'll find out when he flies
> whether it will be detrimental to engine operation. I was mistaken about
> the Q200 builder, he did a 4 into 4 system NOT 4 into 2, I stand corrected.
> But he still claims cooler under-cowl temperatures. Although the crossover
> pipes are several inches away from the sump it still would seem to me that
> some of their heat would end up in the oil. Maybe not, that may be an
> experiment for when the airplane flies. In the meantime I've mounted Larry
> Vetterman's exhaust system on my plane and will fly with it. It's a known
> quantity, I'm not in the mood to do more fabrication at this point and I
> don't have a welder so it's an easy decision. I'm glad Larry is making
> these systems available (so we don't have to do more fabrication),
> especially after 8+ years on the rest of the airplane.
>
> Dean Psiropoulos
> RV-6A N197DM
> Trying to keep the engine cool in the Florida heat....
>
>
>
>
>
>
Dean,
Generally, the air temp under your engine indicates the effectivness of your baffeling.
Higher temps mean that the air is removing the heat from your engine.
It is highly unlikely that the air that has passed over your engine will ever
get hot enough to do any damage. What does create local temps sufficient to do
harm is the radiant energy from 1600 F. exhaust pipes that are glowing cherry
red. Heat shields are very effective at blocking this radiation from heating
less robust components under the cowl. A thin stainless steel shield between
your crossover pipes and oil sump will keep the heat produced by radiation from
exhaust pipes out of the oil.As I recall, Tony Bingless treats this subject
in his "Firewell Forward" book and shows some examples. Also, you can get some
ideas from other homebuild airplanes. I don't believe I've even seen one that
didn't have heat shields in several locations under the cowl.
Bob
-------------- Original message --------------
-- Engines-List message posted by: "DEAN PSIROPOULOS"
<DEAN.PSIROPOULOS@VERIZON.NET>
Thanks for the explanations everyone:
That does make sense to me (about the power pulses and scavenging). I don't
know where my Lancair buddy got his info but we'll find out when he flies
whether it will be detrimental to engine operation. I was mistaken about
the Q200 builder, he did a 4 into 4 system NOT 4 into 2, I stand corrected.
But he still claims cooler under-cowl temperatures. Although the crossover
pipes are several inches away from the sump it still would seem to me that
some of their heat would end up in the oil. Maybe not, that may be an
experiment for when the airplane flies. In the meantime I've mounted Larry
&
gt; Vetterman's exhaust system on my plane and will fly with it. It's a known
quantity, I'm not in the mood to do more fabrication at this point and I
don't have a welder so it's an easy decision. I'm glad Larry is making
these systems available (so we don't have to do more fabrication),
especially after 8+ years on the rest of the airplane.
Dean Psiropoulos
RV-6A N197DM
Trying to keep the engine cool in the Florida heat....
,
Message 2
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| Subject: | Re:Crossover exhaust. |
--> Engines-List message posted by: LessDragProd@aol.com
Hi All,
Massey Aircraft Services in Shafter, CA. had a HR2 with a close fitting cowl
right next to the exhaust pipes. The paint on the outside of the cowl was
getting blisters from the heat of the exhaust pipes.
By visual inspection, they determined that the cowl paint was not blistered
during the flight, the taxi back to parking, or with the engine idling while
parked.
However, within 10 to 20 seconds after engine shutdown, the paint would
blister.
IMHO, perhaps knowing when a problem occurs can lead to better solutions.
Regards,
Jim Ayers
In a message dated 11/24/2005 9:52:59 AM Pacific Standard Time,
n223b@comcast.net writes:
--> Engines-List message posted by: n223b@comcast.net
Dean,
Generally, the air temp under your engine indicates the effectivness of your
baffeling. Higher temps mean that the air is removing the heat from your
engine. It is highly unlikely that the air that has passed over your engine
will ever get hot enough to do any damage. What does create local temps
sufficient to do harm is the radiant energy from 1600 F. exhaust pipes that are
glowing cherry red. Heat shields are very effective at blocking this radiation
from heating less robust components under the cowl. A thin stainless steel
shield between your crossover pipes and oil sump will keep the heat produced
by radiation from exhaust pipes out of the oil. As I recall, Tony Bingless
treats this subject in his "Firewell Forward" book and shows some examples.
Also, you can get some ideas from other homebuild airplanes. I don't believe
I've even seen one that didn't have heat shields in several locations under
the cowl.
Bob
Message 3
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| Subject: | Re:Crossover exhaust. |
--> Engines-List message posted by: "Hans Teijgeler" <hans@jodel.com>
On a similar note:
Initially, I had problems with the exhausts being too close to the cowling,
with the cowling sometimes giving off the very distinct smell of burning
fiberglass.
I solved this by purchasing a $3 roll of aluminum tape from the local
hardware store and taped the inside of the cowling that came closest to the
exhaust. The difference is truly amazing! The cowling stays cold, as if the
exhaust is not even there! The parts farthest away from the exhaust, where I
did not tape, were significantly warmer than the parts that were less than
an inch away from a very hot exhaust pipe, but with the tape in place.
Heat shielding definitely works!
FWIW,
Hans
> -----Original Message-----
> From: owner-engines-list-server@matronics.com [mailto:owner-engines-list-
> server@matronics.com] On Behalf Of n223b@comcast.net
> Sent: donderdag 24 november 2005 18:51
> To: engines-list@matronics.com
> Subject: Re: Engines-List: Re:Crossover exhaust.
>
> --> Engines-List message posted by: n223b@comcast.net
>
> Dean,
>
> Generally, the air temp under your engine indicates the effectivness of
> your baffeling. Higher temps mean that the air is removing the heat from
> your engine. It is highly unlikely that the air that has passed over your
> engine will ever get hot enough to do any damage. What does create local
> temps sufficient to do harm is the radiant energy from 1600 F. exhaust
> pipes that are glowing cherry red. Heat shields are very effective at
> blocking this radiation from heating less robust components under the
> cowl. A thin stainless steel shield between your crossover pipes and oil
> sump will keep the heat produced by radiation from exhaust pipes out of
> the oil. As I recall, Tony Bingless treats this subject in his "Firewell
> Forward" book and shows some examples. Also, you can get some ideas from
> other homebuild airplanes. I don't believe I've even seen one that didn't
> have heat shields in several locations under the cowl.
>
> Bob
>
> -------------- Original message --------------
>
> > --> Engines-List message posted by: "DEAN PSIROPOULOS"
> >
> >
> >
> > Thanks for the explanations everyone:
> >
> > That does make sense to me (about the power pulses and scavenging). I
> don't
> > know where my Lancair buddy got his info but we'll find out when he
> flies
> > whether it will be detrimental to engine operation. I was mistaken about
> > the Q200 builder, he did a 4 into 4 system NOT 4 into 2, I stand
> corrected.
> > But he still claims cooler under-cowl temperatures. Although the
> crossover
> > pipes are several inches away from the sump it still would seem to me
> that
> > some of their heat would end up in the oil. Maybe not, that may be an
> > experiment for when the airplane flies. In the meantime I've mounted
> Larry
> > Vetterman's exhaust system on my plane and will fly with it. It's a
> known
> > quantity, I'm not in the mood to do more fabrication at this point and I
> > don't have a welder so it's an easy decision. I'm glad Larry is making
> > these systems available (so we don't have to do more fabrication),
> > especially after 8+ years on the rest of the airplane.
> >
> > Dean Psiropoulos
> > RV-6A N197DM
> > Trying to keep the engine cool in the Florida heat....
> >
> >
> >
> >
> >
> >
>
> Dean,
>
> Generally, the air temp under your engine indicates the effectivness of
> your baffeling. Higher temps mean that the air is removing the heat from
> your engine. It is highly unlikely that the air that has passed over your
> engine will ever get hot enough to do any damage. What does create local
> temps sufficient to do harm is the radiant energy from 1600 F. exhaust
> pipes that are glowing cherry red. Heat shields are very effective at
> blocking this radiation from heating less robust components under the
> cowl. A thin stainless steel shield between your crossover pipes and oil
> sump will keep the heat produced by radiation from exhaust pipes out of
> the oil.As I recall, Tony Bingless treats this subject in his "Firewell
> Forward" book and shows some examples. Also, you can get some ideas from
> other homebuild airplanes. I don't believe I've even seen one that didn't
> have heat shields in several locations under the cowl.
>
> Bob
>
> -------------- Original message --------------
>
> -- Engines-List message posted by: "DEAN PSIROPOULOS"
> <DEAN.PSIROPOULOS@VERIZON.NET>
>
>
> Thanks for the explanations everyone:
>
> That does make sense to me (about the power pulses and scavenging). I
> don't
> know where my Lancair buddy got his info but we'll find out when he flies
> whether it will be detrimental to engine operation. I was mistaken about
> the Q200 builder, he did a 4 into 4 system NOT 4 into 2, I stand
> corrected.
> But he still claims cooler under-cowl temperatures. Although the
> crossover
> pipes are several inches away from the sump it still would seem to me
> that
> some of their heat would end up in the oil. Maybe not, that may be an
> experiment for when the airplane flies. In the meantime I've mounted
> Larry
> &
> gt; Vetterman's exhaust system on my plane and will fly with it. It's a
> known
> quantity, I'm not in the mood to do more fabrication at this point and I
> don't have a welder so it's an easy decision. I'm glad Larry is making
> these systems available (so we don't have to do more fabrication),
> especially after 8+ years on the rest of the airplane.
>
> Dean Psiropoulos
> RV-6A N197DM
> Trying to keep the engine cool in the Florida heat....
>
>
> ,
>
>
>
>
>
Message 4
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| Subject: | Re:Crossover exhaust. |
--> Engines-List message posted by: "Hans Teijgeler" <hans@jodel.com>
Sorry Jim, I had not read your email yet before sending out mine.
Massey should really try my trick with that tape. It genuinely works, and
that for $3 and twenty minutes of work.
Hans
> -----Original Message-----
> From: owner-engines-list-server@matronics.com [mailto:owner-engines-list-
> server@matronics.com] On Behalf Of LessDragProd@aol.com
> Sent: donderdag 24 november 2005 19:50
> To: engines-list@matronics.com
> Subject: Re: Engines-List: Re:Crossover exhaust.
>
> --> Engines-List message posted by: LessDragProd@aol.com
>
>
> Hi All,
>
> Massey Aircraft Services in Shafter, CA. had a HR2 with a close fitting
> cowl
> right next to the exhaust pipes. The paint on the outside of the cowl
> was
> getting blisters from the heat of the exhaust pipes.
>
> By visual inspection, they determined that the cowl paint was not
> blistered
> during the flight, the taxi back to parking, or with the engine idling
> while
> parked.
>
> However, within 10 to 20 seconds after engine shutdown, the paint would
> blister.
>
> IMHO, perhaps knowing when a problem occurs can lead to better solutions.
>
> Regards,
> Jim Ayers
>
> In a message dated 11/24/2005 9:52:59 AM Pacific Standard Time,
> n223b@comcast.net writes:
>
> --> Engines-List message posted by: n223b@comcast.net
>
> Dean,
>
> Generally, the air temp under your engine indicates the effectivness of
> your
> baffeling. Higher temps mean that the air is removing the heat from your
> engine. It is highly unlikely that the air that has passed over your
> engine
> will ever get hot enough to do any damage. What does create local temps
> sufficient to do harm is the radiant energy from 1600 F. exhaust pipes
> that are
> glowing cherry red. Heat shields are very effective at blocking this
> radiation
> from heating less robust components under the cowl. A thin stainless
> steel
> shield between your crossover pipes and oil sump will keep the heat
> produced
> by radiation from exhaust pipes out of the oil. As I recall, Tony
> Bingless
> treats this subject in his "Firewell Forward" book and shows some
> examples.
> Also, you can get some ideas from other homebuild airplanes. I don't
> believe
> I've even seen one that didn't have heat shields in several locations
> under
> the cowl.
>
> Bob
>
>
>
>
>
Message 5
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| Subject: | Re:Crossover exhaust. |
--> Engines-List message posted by: LessDragProd@aol.com
Hi Hans,
Massey Aircraft did try the aluminum tape. Unfortunately, they only had
about 1/8" of clearance between the exhaust pipe and the front of the cowl. It
didn't help enough.
Sometimes you just have to create your own room, to get the 1" of clearance
so the aluminum tape will work. :-)
Regards,
Jim Ayers
In a message dated 11/24/2005 2:06:19 PM Pacific Standard Time,
hans@jodel.com writes:
--> Engines-List message posted by: "Hans Teijgeler" <hans@jodel.com>
Sorry Jim, I had not read your email yet before sending out mine.
Massey should really try my trick with that tape. It genuinely works, and
that for $3 and twenty minutes of work.
Hans
Message 6
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| Subject: | Re:Crossover exhaust. |
--> Engines-List message posted by: "Archie" <archie97@earthlink.net>
We use a thermal barrier tape wrap on all NASCAR,
and some other racing exhausts for several reasons.
The tape keeps the driver heat down by reducing radiation.
Keeps heat within pipes, which produces a minor increase in hp.
Protects other parts from excessive heat.
We buy in bulk, but small quantities are available from speed shops.
The only drawback is if used with mild steel tubing in humid areas,
can trap moisture and lead to premature corrosion.
Archie
==========================================
----- Original Message -----
From: <LessDragProd@aol.com>
Subject: Re: Engines-List: Re:Crossover exhaust.
> --> Engines-List message posted by: LessDragProd@aol.com
>
>
> Hi Hans,
>
> Massey Aircraft did try the aluminum tape. Unfortunately, they only had
> about 1/8" of clearance between the exhaust pipe and the front of the
> cowl. It
> didn't help enough.
>
> Sometimes you just have to create your own room, to get the 1" of
> clearance
> so the aluminum tape will work. :-)
>
> Regards,
> Jim Ayers
>
> In a message dated 11/24/2005 2:06:19 PM Pacific Standard Time,
> hans@jodel.com writes:
>
> --> Engines-List message posted by: "Hans Teijgeler" <hans@jodel.com>
>
> Sorry Jim, I had not read your email yet before sending out mine.
>
> Massey should really try my trick with that tape. It genuinely works, and
> that for $3 and twenty minutes of work.
>
> Hans
>
>
>
Message 7
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| Subject: | Re:Crossover exhaust. |
--> Engines-List message posted by: Fiveonepw@aol.com
In a message dated 11/24/2005 4:05:26 PM Central Standard Time,
hans@jodel.com writes:
I solved this by purchasing a $3 roll of aluminum tape from the local
hardware store and taped the inside of the cowling that came closest to the
exhaust. The difference is truly amazing!
>>>
Same experience here, Hans- chuck the fancy "heat shields"- the aluminum tape
from Lowes Depot works just fine...
From the PossumWorks in TN
Mark Phillips -6A N51PW 250 hrs.
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