Today's Message Index:
----------------------
1. 08:31 AM - Exit Fairing (mr.gsun@gmail.com)
2. 09:37 AM - Re: Exit Fairing (Ken Cantrell)
3. 09:54 AM - Re: Exit Fairing (mr.gsun@gmail.com)
4. 10:03 AM - Re: Exit Fairing (Larry Bowen)
5. 11:58 AM - Jig Stiffeners? (Charles Brame)
6. 05:38 PM - Re: Exit Fairing (Charlie England)
7. 05:50 PM - Re: Exit Fairing (Kevin Horton)
8. 10:06 PM - Re: Exit Fairing (Reuven Silberman)
Message 1
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Hey RV posters, In my never ending quest for another ounce of velocity,
I installed a cooling air exit fairing at the bottom of the firewall in my
RV-7. IO-360. 4 into 2 Vetterman Exhaust pipes. The idea is to
straighten the exiting cooling airflow to more closely align with the
slipstream. It was one of those easy to install mods that an experienced
RV builder told me about.
It is a curved piece of aluminum about 4" diameter and approximately 10"
long. The lower surface is in line with the bottom of the fuselage. A
photo is attached.
The question is: Has anyone installed this sort of thing before? Did you
get the same ZERO results? Did it cause increased CHTs? My #3 continues
to be too hot but I can't tell if it was affected by this mod. Haven't
decided if it is worth removing it.
Do not archive
Message 2
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Hello,
I finished my RV6 just over 10 years ago and this was being done by some of
my builder friends at that time and I assume a long time before that. I
never did add the fairing myself but thought I should have. When I saw your
picture, my first thought was to copy your fairing but if you're not seeing
positive results, maybe I won't waist the effort.???
Ken Cantrell
Lodi, CA
1275 hrs
From: owner-rv-list-server@matronics.com
[mailto:owner-rv-list-server@matronics.com] On Behalf Of mr.gsun@gmail.com
Sent: Saturday, May 19, 2012 8:30 AM
Subject: RV-List: Exit Fairing
Hey RV posters, In my never ending quest for another ounce of velocity, I
installed a cooling air exit fairing at the bottom of the firewall in my
RV-7. IO-360. 4 into 2 Vetterman Exhaust pipes. The idea is to
straighten the exiting cooling airflow to more closely align with the
slipstream. It was one of those easy to install mods that an experienced
RV builder told me about.
It is a curved piece of aluminum about 4" diameter and approximately 10"
long. The lower surface is in line with the bottom of the fuselage. A
photo is attached.
The question is: Has anyone installed this sort of thing before? Did you
get the same ZERO results? Did it cause increased CHTs? My #3 continues to
be too hot but I can't tell if it was affected by this mod. Haven't decided
if it is worth removing it.
Do not archive
Message 3
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Ken
I just can't measure any results.
Greg
On May 19, 2012 9:46 AM, "Ken Cantrell" <kcflyrv@comcast.net> wrote:
> Hello,****
>
> ** **
>
> I finished my RV6 just over 10 years ago and this was being done by some
> of my builder friends at that time and I assume a long time before that.
I
> never did add the fairing myself but thought I should have. When I saw yo
ur
> picture, my first thought was to copy your fairing but if you=92re not se
eing
> positive results, maybe I won=92t waist the effort.???****
>
> ** **
>
> Ken Cantrell****
>
> Lodi, CA****
>
> 1275 hrs****
>
> ** **
>
> *From:* owner-rv-list-server@matronics.com [mailto:
> owner-rv-list-server@matronics.com] *On Behalf Of *mr.gsun@gmail.com
> *Sent:* Saturday, May 19, 2012 8:30 AM
> *To:* rv-list@matronics.com
> *Subject:* RV-List: Exit Fairing****
>
> ** **
>
> Hey RV posters, In my never ending quest for another ounce of velocity
,
> I installed a cooling air exit fairing at the bottom of the firewall in m
y
> RV-7. IO-360. 4 into 2 Vetterman Exhaust pipes. The idea is to
> straighten the exiting cooling airflow to more closely align with the
> slipstream. It was one of those easy to install mods that an experience
d
> RV builder told me about.
>
> It is a curved piece of aluminum about 4" diameter and approximately 10"
> long. The lower surface is in line with the bottom of the fuselage. A
> photo is attached.
>
> The question is: Has anyone installed this sort of thing before? Did yo
u
> get the same ZERO results? Did it cause increased CHTs? My #3 continues
> to be too hot but I can't tell if it was affected by this mod. Haven't
> decided if it is worth removing it.
>
> Do not archive****
>
> *
>
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> *
>
>
Message 4
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That's the same ramp that is on the RV8, per plans and prefabricated, as
you probably already knew. Not sure why the 7 is different.
-
Larry Bowen
Larry@BowenAero.com
http://BowenAero.com
On May 19, 2012 12:56 PM, <mr.gsun@gmail.com> wrote:
> Ken
> I just can't measure any results.
>
> Greg
> On May 19, 2012 9:46 AM, "Ken Cantrell" <kcflyrv@comcast.net> wrote:
>
>> Hello,****
>>
>> ** **
>>
>> I finished my RV6 just over 10 years ago and this was being done by some
>> of my builder friends at that time and I assume a long time before that.
I
>> never did add the fairing myself but thought I should have. When I saw y
our
>> picture, my first thought was to copy your fairing but if you=92re not s
eeing
>> positive results, maybe I won=92t waist the effort.???****
>>
>> ** **
>>
>> Ken Cantrell****
>>
>> Lodi, CA****
>>
>> 1275 hrs****
>>
>> ** **
>>
>> *From:* owner-rv-list-server@matronics.com [mailto:
>> owner-rv-list-server@matronics.com] *On Behalf Of *mr.gsun@gmail.com
>> *Sent:* Saturday, May 19, 2012 8:30 AM
>> *To:* rv-list@matronics.com
>> *Subject:* RV-List: Exit Fairing****
>>
>> ** **
>>
>> Hey RV posters, In my never ending quest for another ounce of
>> velocity, I installed a cooling air exit fairing at the bottom of the
>> firewall in my RV-7. IO-360. 4 into 2 Vetterman Exhaust pipes. The
>> idea is to straighten the exiting cooling airflow to more closely align
>> with the slipstream. It was one of those easy to install mods that an
>> experienced RV builder told me about.
>>
>> It is a curved piece of aluminum about 4" diameter and approximately 10"
>> long. The lower surface is in line with the bottom of the fuselage. A
>> photo is attached.
>>
>> The question is: Has anyone installed this sort of thing before? Did
>> you get the same ZERO results? Did it cause increased CHTs? My #3
>> continues to be too hot but I can't tell if it was affected by this mod.
>> Haven't decided if it is worth removing it.
>>
>> Do not archive****
>>
>> *
>>
>> t="_blank">http://www.matronics.com/Navigator?RV-List
>> tp://forums.matronics.com
>> _blank">http://www.matronics.com/contribution
>> *
>>
>> *
>
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> *
>
>
Message 5
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Hey guys,
Its been nearly 12 years since I built the elevators and rudder for my
RV-6. I recently damaged my right elevator and need to replace the
skin and stiffeners. My feeble memory seems to recall I made a small
jig that greatly sped up shaping and drilling the stiffeners, but I
cannot recall how the jig was made and/or how it was used. Can anybody
help?
Charlie Brame
RV-6A N11CB
San Antonio
Message 6
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| Subject: | Re: Exit Fairing |
On 05/19/2012 10:30 AM, mr.gsun@gmail.com wrote:
> Hey RV posters, In my never ending quest for another ounce of
> velocity, I installed a cooling air exit fairing at the bottom of the
> firewall in my RV-7. IO-360. 4 into 2 Vetterman Exhaust pipes.
> The idea is to straighten the exiting cooling airflow to more closely
> align with the slipstream. It was one of those easy to install mods
> that an experienced RV builder told me about.
>
> It is a curved piece of aluminum about 4" diameter and approximately
> 10" long. The lower surface is in line with the bottom of the
> fuselage. A photo is attached.
>
> The question is: Has anyone installed this sort of thing before? Did
> you get the same ZERO results? Did it cause increased CHTs? My #3
> continues to be too hot but I can't tell if it was affected by this
> mod. Haven't decided if it is worth removing it.
>
> Do not archive
There's a very long and on-going discussion on the VAF forum about cowl
exit experiments (with not much useful info).
As someone else said, the firewall treatment is standard on the -8. I
think that all the really fast RV's have something similar to that, or
something much more elaborate (ramps that extend all the way up to the
cylinders, in a lot of cases).
One thing to think about in your installation is the horizontal brace on
the exhaust pipes. It's round (plus the hose clamps), meaning that
you've got a really draggy structure directly in the exit path. Could
you run separate braces from each pipe outward, instead of across the exit?
Charlie
Message 7
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| Subject: | Re: Exit Fairing |
A smooth, rounded ramp like that should lead to a decrease in CHTs, in theory.
But, the devil is in the details. I can't tell from the picture, but is it possible
that the bottom of that fairing extends down far enough to decrease the
exit area from what it would be if the fairing was not installed? If so, it
is quite possible that you have less air flowing than before, and thus may see
an increase in CHTs. Normally, if there is less air flowing, there should be
less cooling drag, and a speed increase. But, the decrease in air flow, with
the same frontal area from the part of the cowling that is dropped down where
the exhaust pipes exit, would give extra wake drag which may cancel out the
decrease in cooling drag.
Ideally, the rounded radius would end on a tangent to the bottom of the fuselage.
If the radius keeps going so there is a sharp corner where it meets the bottom
of the fuselage, there May be some flow separation behind the radius, leading
to extra drag.
Kevin Horton
Sent from my iPad
On 2012-05-19, at 11:30 AM, mr.gsun@gmail.com wrote:
> Hey RV posters, In my never ending quest for another ounce of velocity, I
installed a cooling air exit fairing at the bottom of the firewall in my RV-7.
IO-360. 4 into 2 Vetterman Exhaust pipes. The idea is to straighten the
exiting cooling airflow to more closely align with the slipstream. It was one
of those easy to install mods that an experienced RV builder told me about.
>
> It is a curved piece of aluminum about 4" diameter and approximately 10" long.
The lower surface is in line with the bottom of the fuselage. A photo is attached.
>
> The question is: Has anyone installed this sort of thing before? Did you get
the same ZERO results? Did it cause increased CHTs? My #3 continues to be
too hot but I can't tell if it was affected by this mod. Haven't decided if it
is worth removing it.
>
> Do not archive
> <exit fairing RV7.jpg>
Message 8
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| Subject: | Re: Exit Fairing |
Cooling is an art, science, and black magic all rolled into one.- If your
looking for efficient cooling read LoPersit or Lazlo Pazmany's stuff.- Y
ou can also-Google aircraft piston engine cooling and you will get pages
of stuff.=0A-=0AIf you having problems with one cyl- look from the top
down between the cooling fins in and around the spark plug and top the the
cyl and clean out all the casting slag.- =0A-=0AReuven Silberman--
=0A=0AEnjoy life now=0AIt has an expiration date.=0A =0A=0A________________
________________=0A From: Kevin Horton <khorton02@gmail.com>=0ATo: "rv-list
@matronics.com" <rv-list@matronics.com> =0ASent: Saturday, May 19, 2012 5:4
9 PM=0ASubject: Re: RV-List: Exit Fairing=0A =0A--> RV-List message posted
by: Kevin Horton <khorton02@gmail.com>=0A=0AA smooth, rounded ramp like th
at should lead to a decrease in CHTs, in theory.- But, the devil is in th
e details.- I can't tell from the picture, but is it possible that the bo
ttom of that fairing extends down far enough to decrease the exit area from
what it would be if the fairing was not installed?- If so, it is quite p
ossible that you have less air flowing than before, and thus may see an inc
rease in CHTs.- Normally, if there is less air flowing, there should be l
ess cooling drag, and a speed increase.- But, the decrease in air flow, w
ith the same frontal area from the part of the cowling that is dropped down
where the exhaust pipes exit, would give extra wake drag which may cancel
out the decrease in cooling drag.=0A=0AIdeally, the rounded radius would en
d on a tangent to the bottom of the fuselage.- If the radius keeps going
so there is a sharp corner where it meets the bottom of the fuselage, there
May be some flow separation behind the radius, leading to extra drag.=0A
=0AKevin Horton=0A=0ASent from my iPad=0A=0AOn 2012-05-19, at 11:30 AM, mr.
gsun@gmail.com wrote:=0A=0A> Hey RV posters,- - In my never ending ques
t for another ounce of velocity, I installed a cooling air exit fairing at
the bottom of the firewall in my RV-7.- - IO-360.- 4 into 2 Vetterman
Exhaust pipes.- The idea is to straighten the exiting cooling airflow t
o more closely align with the slipstream.- It was one of those easy to i
nstall mods that an experienced RV builder told me about.=0A> =0A> It is a
curved piece of aluminum about 4" diameter and approximately 10" long.- T
he lower surface is in line with the bottom of the fuselage.- A photo is
attached.=0A> =0A> The question is:- Has anyone installed this sort of th
ing before?- Did you get the same ZERO results?- Did it cause increased
CHTs?- My #3 continues to be too hot but I can't tell if it was affected
by this mod.- Haven't decided if it is worth removing it.=0A> =0A> Do no
=
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