Today's Message Index:
----------------------
1. 04:55 AM - Re: Louvers (rveighta@comcast.net)
2. 05:28 AM - Engine Hesitation - Update (rveighta@comcast.net)
3. 09:51 AM - Re: Engine Hesitation - Update (Larry Bowen)
4. 11:24 AM - Re: Louvers (Greg Young)
5. 12:23 PM - Re: Louvers (John Danielson)
6. 01:23 PM - Re: Louvers (Tailgummer@aol.com)
7. 01:57 PM - Re: Louvers (Tracy Crook)
8. 08:59 PM - Re: Louvers (charlie heathco)
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| Subject: | Engine Hesitation - Update |
Guys, I really appreciate the outpouring of advice I received concerning my
engine "hesitation" problem. I've been
on this list since 1998 and seen some flame wars that almost consumed us, b
ut somehow we always seem to
get our bearings and get back to providing building advice to those in need
.
To recap, I have an IO-360 B4A engine in my RV8A that exhibits a "hesitatio
n" or "stumble" after taxiing in from
a flight on warm days (doesn't happen in winter). My gut feeling from the b
eginning was that this had to be due
to fuel vaporization, but being unsure, I tried a number of things to corre
ct the problem:
(1) Reset idle mixture
(2) Removed and cleaned injection nozzles in a sonic cleaner
(3) Experimented with tie wrapping insulation on the lines from the flow di
vider
(4) Oiled the fuel selector valve
(5) Cleaned and gapped sparkplugs
(6) Checked for air induction leak using soapy water then starter fluid
None of the above action has corrected the problem, although after celaning
the injectors the stumbles seemed
to occur less often.
Yesterday, as a result of an email by Kevin Horton, I called Don Rivera (re
ally nice guy and very knowledgable) at
Airflow Performance. I described my symptoms and right away he said the fue
l in the flow divider and capillary lines
was boiling due to the lack of adequate airflow under the cowl after landin
g. He recommended I go to=C2- smaller
diameter nozzles which would increase the pressure and reduce the possibili
ty of vaporization. After some
calculation, Don decided on the best size nozzle ( I believe it was .022"),
and I ordered the nozzles ($40/ea).
I should have the new nozzles by tomorrow afternoon or Monday. I'll install
them and let you know how this works
out. I should point out that Don does NOT guarantee the problem will be ent
irely gone. But he said it should
greatly improve engine smoothness. We shall see.......
Thanks again for all your help, guys!
Walt Shipley
Chuckey, TN
Message 3
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| Subject: | Re: Engine Hesitation - Update |
Good news.
Is there an expected trade off? Otherwise why not go with the smaller
from the start?
On 9/17/09, rveighta@comcast.net <rveighta@comcast.net> wrote:
>
>
> Guys, I really appreciate the outpouring of advice I received concerning my
> engine "hesitation" problem. I've been
>
> on this list since 1998 and seen some flame wars that almost consumed us,
> but somehow we always seem to
>
> get our bearings and get back to providing building advice to those in need.
>
>
> To recap, I have an IO-360 B4A engine in my RV8A that exhibits a
> "hesitation" or "stumble" after taxiing in from
>
> a flight on warm days (doesn't happen in winter). My gut feeling from the
> beginning was that this had to be due
>
> to fuel vaporization, but being unsure, I tried a number of things to
> correct the problem:
>
>
> (1) Reset idle mixture
>
> (2) Removed and cleaned injection nozzles in a sonic cleaner
>
> (3) Experimented with tie wrapping insulation on the lines from the flow
> divider
>
> (4) Oiled the fuel selector valve
>
> (5) Cleaned and gapped sparkplugs
>
> (6) Checked for air induction leak using soapy water then starter fluid
>
>
> None of the above action has corrected the problem, although after celaning
> the injectors the stumbles seemed
>
> to occur less often.
>
>
> Yesterday, as a result of an email by Kevin Horton, I called Don Rivera
> (really nice guy and very knowledgable) at
>
> Airflow Performance. I described my symptoms and right away he said the fuel
> in the flow divider and capillary lines
>
> was boiling due to the lack of adequate airflow under the cowl after
> landing. He recommended I go to smaller
>
> diameter nozzles which would increase the pressure and reduce the
> possibility of vaporization. After some
>
> calculation, Don decided on the best size nozzle ( I believe it was .022"),
> and I ordered the nozzles ($40/ea).
>
>
> I should have the new nozzles by tomorrow afternoon or Monday. I'll install
> them and let you know how this works
>
> out. I should point out that Don does NOT guarantee the problem will be
> entirely gone. But he said it should
>
> greatly improve engine smoothness. We shall see.......
>
>
> Thanks again for all your help, guys!
>
>
> Walt Shipley
>
> Chuckey, TN
>
--
--
Larry Bowen
Larry@BowenAero.com
http://BowenAero.com
Message 4
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The sides might be better. I heard a report (I think it was an RV-10) that
had bottom mounted louvers that did not help much but moving to the side
did. The theory was that high AOA on climb pressurized the bottom of the
cowling preventing the louvers from being as effective as they were in level
flight. Something to consider.
Regards,
Greg Young
_____
From: owner-rv-list-server@matronics.com
[mailto:owner-rv-list-server@matronics.com] On Behalf Of Tracy Crook
Sent: Wednesday, September 16, 2009 8:17 PM
Subject: Re: RV-List: Louvers
Excellent! Direct before & after results with all else being the same is
the best kind of data.
I'd be interested in exactly where you mounted the louvers. I've been
assuming that on an RV-8 they would go on either side of the cooling duct
'trough' on the lower cowl. Is that where you put them? I'm assuming you
used a pair of the Avery type louvers?
I'll be happy to deal with the low temperatures in winter.
Tracy Crook
On Wed, Sep 16, 2009 at 8:51 PM, <rveighta@comcast.net> wrote:
I guess I started the latest thread on louvers, so let me throw my two cents
in: I installed them on my 8A after experiencing
high oil temps. Prior to the louvers, I was running 225 or so on a hot day.
Now, I rarely see in excess of 190. So, then I built
an RV8 and having similar temperature issues, I installed a pair of louvers
in it as well. Same results, oil temps went down
dramatically. The only problem with both the planes was getting the oil
temps HIGH enough in winter (I solved that by making
blanks to install between the inside of the cowl and the louvers).
So, I can only say what worked for me. Maybe louvers won't work for you.
Walt
Message 5
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I had a problem with higher oil temps back in 2002.
I installed vortex generators at the aft end of the cowl opening.
This did wonders for my oil temp. and have never had any problems since.
John Danielson
-----Original Message-----
From: owner-rv-list-server@matronics.com [mailto:owner-rv-list-server@matronics.com] On Behalf Of Charlie England
Sent: Wednesday, September 16, 2009 7:50 PM
Subject: Re: RV-List: Louvers
Tracy,
Have you seen the stuff on the CAFE web site?
http://cafefoundation.org/v2/main_home.php
Click the 'research' tab, then 'cafe reports', then 'local flow I, II, &
III.
II discusses louvers & 'bluff bodies'.
Charlie
Tracy Crook wrote:
> Excellent! Direct before & after results with all else being the same
> is the best kind of data.
>
> I'd be interested in exactly where you mounted the louvers. I've been
> assuming that on an RV-8 they would go on either side of the cooling
> duct 'trough' on the lower cowl. Is that where you put them? I'm
> assuming you used a pair of the Avery type louvers?
>
> I'll be happy to deal with the low temperatures in winter.
>
> Tracy Crook
>
> On Wed, Sep 16, 2009 at 8:51 PM, <rveighta@comcast.net
> <mailto:rveighta@comcast.net>> wrote:
>
> I guess I started the latest thread on louvers, so let me throw my
> two cents in: I installed them on my 8A after experiencing
>
> high oil temps. Prior to the louvers, I was running 225 or so on a
> hot day. Now, I rarely see in excess of 190. So, then I built
>
> an RV8 and having similar temperature issues, I installed a pair
> of louvers in it as well. Same results, oil temps went down
>
> dramatically. The only problem with both the planes was getting
> the oil temps HIGH enough in winter (I solved that by making
>
> blanks to install between the inside of the cowl and the louvers).
>
>
>
> So, I can only say what worked for me. Maybe louvers won't work
> for you.
>
>
>
> Walt
>
Message 6
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Ingenious, John! Did these have any effect on your CHT's?
John D'Onofrio
Message 7
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I thought the higher pressure on bottom of cowl might be a problem as well.
Latest test would seem to verify that. I keep changing my mind about what
to try first and settled on hinging the -8 cooling exit ramp on the bottom
cowl and make it a movable cowl flap. I cut the ramp out starting about 15
inches in front of the aft edge. Before doing the movable flap I did a
test flight with the big gaping hole (about 13 X 15") in the bottom cowl
just to see what would happen. It ran about 15 degrees cooler than the
stock cowl opening but nothing like the 60 deg. drop I got with the cowl
off.
Checked out the CAFE data that Charlie suggested and have a few ideas from
there I want to try as well.
Tracy
On Thu, Sep 17, 2009 at 2:23 PM, Greg Young <gyoung@cs-sol.com> wrote:
> The sides might be better. I heard a report (I think it was an RV-10)
> that had bottom mounted louvers that did not help much but moving to the
> side did. The theory was that high AOA on climb pressurized the bottom of
> the cowling preventing the louvers from being as effective as they were in
> level flight. Something to consider.
>
> Regards,
> Greg Young
>
>
> ------------------------------
> *From:* owner-rv-list-server@matronics.com [mailto:
> owner-rv-list-server@matronics.com] *On Behalf Of *Tracy Crook
> *Sent:* Wednesday, September 16, 2009 8:17 PM
> *To:* rv-list@matronics.com
> *Subject:* Re: RV-List: Louvers
>
> Excellent! Direct before & after results with all else being the same is
> the best kind of data.
>
> I'd be interested in exactly where you mounted the louvers. I've been
> assuming that on an RV-8 they would go on either side of the cooling duct
> 'trough' on the lower cowl. Is that where you put them? I'm assuming you
> used a pair of the Avery type louvers?
>
> I'll be happy to deal with the low temperatures in winter.
>
> Tracy Crook
>
> On Wed, Sep 16, 2009 at 8:51 PM, <rveighta@comcast.net> wrote:
>
>> I guess I started the latest thread on louvers, so let me throw my two
>> cents in: I installed them on my 8A after experiencing
>>
>> high oil temps. Prior to the louvers, I was running 225 or so on a hot
>> day. Now, I rarely see in excess of 190. So, then I built
>>
>> an RV8 and having similar temperature issues, I installed a pair of
>> louvers in it as well. Same results, oil temps went down
>>
>> dramatically. The only problem with both the planes was getting the oil
>> temps HIGH enough in winter (I solved that by making
>>
>> blanks to install between the inside of the cowl and the louvers).
>>
>>
>>
>> So, I can only say what worked for me. Maybe louvers won't work for you.
>>
>>
>>
>> Walt
>>
>> **
>>
>> *
>
> *
>
>
Message 8
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John, could you give some details, maybe pix of those V G's? Charlie
----- Original Message -----
From: "John Danielson" <johnd@wlcwyo.com>
Sent: Thursday, September 17, 2009 14:22
Subject: RE: RV-List: Louvers
I had a problem with higher oil temps back in 2002.
I installed vortex generators at the aft end of the cowl opening.
This did wonders for my oil temp. and have never had any problems since.
John Danielson
-----Original Message-----
From: owner-rv-list-server@matronics.com
[mailto:owner-rv-list-server@matronics.com] On Behalf Of Charlie England
Sent: Wednesday, September 16, 2009 7:50 PM
Subject: Re: RV-List: Louvers
Tracy,
Have you seen the stuff on the CAFE web site?
http://cafefoundation.org/v2/main_home.php
Click the 'research' tab, then 'cafe reports', then 'local flow I, II, &
III.
II discusses louvers & 'bluff bodies'.
Charlie
Tracy Crook wrote:
> Excellent! Direct before & after results with all else being the same
> is the best kind of data.
>
> I'd be interested in exactly where you mounted the louvers. I've been
> assuming that on an RV-8 they would go on either side of the cooling
> duct 'trough' on the lower cowl. Is that where you put them? I'm
> assuming you used a pair of the Avery type louvers?
>
> I'll be happy to deal with the low temperatures in winter.
>
> Tracy Crook
>
> On Wed, Sep 16, 2009 at 8:51 PM, <rveighta@comcast.net
> <mailto:rveighta@comcast.net>> wrote:
>
> I guess I started the latest thread on louvers, so let me throw my
> two cents in: I installed them on my 8A after experiencing
>
> high oil temps. Prior to the louvers, I was running 225 or so on a
> hot day. Now, I rarely see in excess of 190. So, then I built
>
> an RV8 and having similar temperature issues, I installed a pair
> of louvers in it as well. Same results, oil temps went down
>
> dramatically. The only problem with both the planes was getting
> the oil temps HIGH enough in winter (I solved that by making
>
> blanks to install between the inside of the cowl and the louvers).
>
>
> So, I can only say what worked for me. Maybe louvers won't work
> for you.
>
>
> Walt
>
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