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dlm34077(at)gmail.com
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 Posted: Wed Sep 01, 2021 10:11 am Post subject: Cooling |
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Has anyone made a cowl mod to improve cooling behind the baffling and forward of the firewall?. Living in Arizona leaves me with excess heat in that area, I have an air intake on top portion of baffling near cylinder 5 but the 1 inch line takes in air passing over the clys 1,3,5 before sending it behind the baffling.After shutdown,although I open the oil door , the temps still rise behind the baffling. The result is that the avionics backup battery only lasts about two years when other Odyssey 680s last 5-8 years when installed aft of the baggage closeout.what have others done for excess heat? cowl flaps or vents?
David Mcneill.
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Kellym
Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ
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| Posted: Wed Sep 01, 2021 12:13 pm Post subject: Cooling |
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Dave,
I tried the Anti-splat cowl flaps. They work fine in concept, but are
built with RC actuators using plastic wiring and connectors that cannot
withstand the heat, and the actuators themselves are sensitive to heat.
So I took them off, restored the original louvers, then placed an air
dam about 3/4" tall in front of the louvers, on the outside, which
creates a low pressure area, drawing heat out of cowling. That has
worked for me, but I don't have any batteries or other electronics on
the firewall.
Kelly
On 9/1/2021 11:10 AM, dlm wrote:
| Quote: | Has anyone made a cowl mod to improve cooling behind the baffling and
forward of the firewall?. Living in Arizona leaves me with excess heat
in that area, I have an air intake on top portion of baffling near
cylinder 5 but the 1 inch line takes in air passing over the clys 1,3,5
before sending it behind the baffling.After shutdown,although I open the
oil door , the temps still rise behind the baffling. The result is that
the avionics backup battery only lasts about two years when other
Odyssey 680s last 5-8 years when installed aft of the baggage
closeout.what have others done for excess heat? cowl flaps or vents?
David Mcneill.
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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD |
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carl.froehlich(at)verizon
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| Posted: Wed Sep 01, 2021 1:46 pm Post subject: Cooling |
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A few of thoughts:
- The firewall mounted heat valves will do a lot of conductive heating to the firewall. I use a piece of this stuff between the valves and the firewall, having excess at the top that lays over the front of the valves: https://www.aircraftspruce.com/pages/ep/engineaccessories_heatshields/koolmat.php This does two things, it breaks the heat conduction path and directs the dumped heat muff hot air down toward the cowl exit instead of the engine (and engine mounted fuel pump).
- You can take steps to insulate the engine side of the firewall. There are several options in addition to the above KoolMat such as https://www.aircraftspruce.com/pages/ep/engineaccessories_heatshields/firewall2000.php). On the RV-8 I used FiberFrax https://www.aircraftspruce.com/catalog/appages/fiberfrax.php
then put a piece of 0.005” SS over it. Dan Horton has a lot of excellent VAF posts on how to do this). As he points out, insulation the cabin side of the firewall is not the way to go as insulation off gassing is a danger.
- If you don’t have a couple of muffin fans mounted on the glare shield, you should. In addition to defogging, they pump out a lot of hot air from the avionics.
Carl
| Quote: | On Sep 1, 2021, at 2:21 PM, dlm <dlm34077(at)gmail.com> wrote:
Has anyone made a cowl mod to improve cooling behind the baffling and forward of the firewall?. Living in Arizona leaves me with excess heat in that area, I have an air intake on top portion of baffling near cylinder 5 but the 1 inch line takes in air passing over the clys 1,3,5 before sending it behind the baffling.After shutdown,although I open the oildoor , the temps still rise behind the baffling. The result is that the avionics backup battery only lasts about two years when other Odyssey 680s last 5-8 years when installed aft of the baggage closeout.what have others done for excess heat? cowl flaps or vents?
David Mcneill.
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Dave Saylor
Joined: 11 Jan 2015
Posts: 210
Location: GILROY, CA
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| Posted: Wed Sep 01, 2021 7:22 pm Post subject: Cooling |
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Not exactly an answer to your question but I recently installed the Vans access panels forward of the windshield. That gives great access to the back side of the firewall if you were to consider moving the battery there. I think the kit was $19 for two panels, doublers, and hardware. It was a pretty easy mod.
I had a backup battery on top of the far forward end of the tunnel for many years. It worked fine there.
--Dave
On Wed, Sep 1, 2021 at 1:23 PM Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)> wrote:
| Quote: | --> RV10-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>
Dave,
I tried the Anti-splat cowl flaps. They work fine in concept, but are
built with RC actuators using plastic wiring and connectors that cannot
withstand the heat, and the actuators themselves are sensitive to heat.
So I took them off, restored the original louvers, then placed an air
dam about 3/4" tall in front of the louvers, on the outside, which
creates a low pressure area, drawing heat out of cowling. That has
worked for me, but I don't have any batteries or other electronics on
the firewall.
Kelly
On 9/1/2021 11:10 AM, dlm wrote:
> Has anyone made a cowl mod to improve cooling behind the baffling and
> forward of the firewall?. Living in Arizona leaves me with excess heat
> in that area, I have an air intake on top portion of baffling near
> cylinder 5 but the 1 inch line takes in air passing over the clys 1,3,5
> before sending it behind the baffling.After shutdown,although I open the
> oil door , the temps still rise behind the baffling. The result is that
> the avionics backup battery only lasts about two years when other
> Odyssey 680s last 5-8 years when installed aft of the baggage
> closeout.what have others done for excess heat? cowl flaps or vents?
>
> David Mcneill.
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rjones560xl@gmail.com
Joined: 29 Jul 2015
Posts: 64
Location: Las Vegas, NV
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| Posted: Thu Sep 02, 2021 7:37 am Post subject: Cooling |
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What kind of battery are you using for avionics backup? Is it the Odyssey 680 as you seem to infer without actually saying so? I am running an EarthX ETX900 on the firewall as my main ships battery. I have a Dynon 3 screen EFIS setup with a Dynon backup battery on each screen. My ETX900 ran hot until I modified the battery box and put a blast tube on it. I live in LAS and I have flown when the temp was 110F with no problem. You might consider one of the vented EarthX batteries behind the firewall for a backup to avoid the heat. You get a lot of power for the weight. I might ask, what avionics package do you have, and have you installed a second alternator on the vacuum pad. I did and consider it a better deal than another battery. I set the alternators up with a 3 position switch. Only one alternator can be selected at a time.
Heat buildup behind the baffles after shutdown is an unavoidable problem as latent heat from the engine is going to heat up that area. The problem is not how hot it gets in flight because there is constant air movement. The problem is latent heat after shutdown as I am sure you are well aware. Additional cooling during flight is probably not going to help.
I would love to hear anyone else’s ideas on this as I do not consider myself an expert at all. However I did get an award for Outstanding Workmanship at Airventure this year for N810RK so I did manage to learn a little during the 10 years I took to build it.
Robert Jones
| Quote: | On Sep 1, 2021, at 11:15 AM, dlm <dlm34077(at)gmail.com> wrote:
Has anyone made a cowl mod to improve cooling behind the baffling and forward of the firewall?. Living in Arizona leaves me with excess heat in that area, I have an air intake on top portion of baffling near cylinder 5 but the 1 inch line takes in air passing over the clys 1,3,5 before sending it behind the baffling.After shutdown,although I open the oil door , the temps still rise behind the baffling. The result is that the avionics backup battery only lasts about two years when other Odyssey 680s last 5-8 years when installed aft of the baggage closeout.what have others done for excess heat? cowl flaps or vents?
David Mcneill.
|
| | - The Matronics RV10-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV10-List |
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Robert J Jones
702-521-1840 |
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Ceengland
Joined: 11 Oct 2020
Posts: 393
Location: MS
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| Posted: Thu Sep 02, 2021 9:43 am Post subject: Cooling |
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Congrats on the award!
Slight detour from the subject, but I noticed that you are using one
switch to control both alts. It may be a very reliable switch, but a
multi-position switch in that application *is* a single point of failure
for the whole charging system. Probably not a big deal in a VFR,
conventional engine'd a/c, but for IFR or an electrically dependent
(electronic injection) engine, it's something to think about.
Charlie
On 9/2/2021 10:36 AM, Robert Jones wrote:
| Quote: |
What kind of battery are you using for avionics backup? Is it the Odyssey 680 as you seem to infer without actually saying so? I am running an EarthX ETX900 on the firewall as my main ships battery. I have a Dynon 3 screen EFIS setup with a Dynon backup battery on each screen. My ETX900 ran hot until I modified the battery box and put a blast tube on it. I live in LAS and I have flown when the temp was 110F with no problem. You might consider one of the vented EarthX batteries behind the firewall for a backup to avoid the heat. You get a lot of power for the weight. I might ask, what avionics package do you have, and have you installed a second alternator on the vacuum pad. I did and consider it a better deal than another battery. I set the alternators up with a 3 position switch. Only one alternator can be selected at a time.
Heat buildup behind the baffles after shutdown is an unavoidable problem as latent heat from the engine is going to heat up that area. The problem is not how hot it gets in flight because there is constant air movement. The problem is latent heat after shutdown as I am sure you are well aware. Additional cooling during flight is probably not going to help.
I would love to hear anyone else’s ideas on this as I do not consider myself an expert at all. However I did get an award for Outstanding Workmanship at Airventure this year for N810RK so I did manage to learn a little during the 10 years I took to build it.
Robert Jones
> On Sep 1, 2021, at 11:15 AM, dlm <dlm34077(at)gmail.com> wrote:
>
>
> Has anyone made a cowl mod to improve cooling behind the baffling and forward of the firewall?. Living in Arizona leaves me with excess heat in that area, I have an air intake on top portion of baffling near cylinder 5 but the 1 inch line takes in air passing over the clys 1,3,5 before sending it behind the baffling.After shutdown,although I open the oil door , the temps still rise behind the baffling. The result is that the avionics backup battery only lasts about two years when other Odyssey 680s last 5-8 years when installed aft of the baggage closeout.what have others done for excess heat? cowl flaps or vents?
|
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| | - The Matronics RV10-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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Charlie |
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rjones560xl@gmail.com
Joined: 29 Jul 2015
Posts: 64
Location: Las Vegas, NV
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| Posted: Thu Sep 02, 2021 4:00 pm Post subject: Cooling |
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The switch is a very high quality switch that provides a very small ground signal to a terminal on the VPX PRO, which turns on the field for one alternator, or the other. Running both alternators at the same time is generally not a good idea. My lithium iron battery has a tendency to really suck up the amps after startup (it goes right to 60 amps) and the battery I have is only rated for a 60 amp alternator. That is one reason for a single switch. However, I can turn on either field through the VPX PRO even if the switch fails, which is true for everything else also so I do have a backup. It’s a serious IFR aircraft. I have 3 GPS receivers, 2 DYNON and one Garmin, and a VOR receiver.
Robert Jones
| Quote: | On Sep 2, 2021, at 10:48 AM, Charlie England <ceengland7(at)gmail.com> wrote:
Congrats on the award!
Slight detour from the subject, but I noticed that you are using one switch to control both alts. It may be a very reliable switch, but a multi-position switch in that application *is* a single point of failure for the whole charging system. Probably not a big deal in a VFR, conventional engine'd a/c, but for IFR or an electrically dependent (electronic injection) engine, it's something to think about.
Charlie
> On 9/2/2021 10:36 AM, Robert Jones wrote:
>
>
> What kind of battery are you using for avionics backup? Is it the Odyssey 680 as you seem to infer without actually saying so? I am running an EarthX ETX900 on the firewall as my main ships battery. I have a Dynon 3 screen EFIS setup with a Dynon backup battery on each screen. My ETX900 ran hot until I modified the battery box and put a blast tube on it. I live in LAS and I have flown when the temp was 110F with no problem. You might consider one of the vented EarthX batteries behind the firewall for a backup to avoid the heat. You get a lot of power for the weight. I might ask, what avionics package do you have, and have you installed a second alternator on the vacuum pad. I did and consider it a better deal than another battery. I set the alternators up with a 3 position switch. Only one alternator can be selected at a time.
>
> Heat buildup behind the baffles after shutdown is an unavoidable problem as latent heat from the engine is going to heat up that area. The problem is not how hot it gets in flight because there is constant air movement. The problem is latent heat after shutdown as I am sure you are well aware. Additional cooling during flight is probably not going to help.
>
> I would love to hear anyone else’s ideas on this as I do not consider myself an expert at all. However I did get an award for Outstanding Workmanship at Airventure this year for N810RK so I did manage to learn a little during the 10 years I took to build it.
>
> Robert Jones
>
>>> On Sep 1, 2021, at 11:15 AM, dlm <dlm34077(at)gmail.com> wrote:
>>
>>
>> Has anyone made a cowl mod to improve cooling behind the baffling and forward of the firewall?. Living in Arizona leaves me with excess heat in that area, I have an air intake on top portion of baffling near cylinder 5 but the 1 inch line takes in air passing over the clys 1,3,5 before sending it behind the baffling.After shutdown,although I open the oil door , the temps still rise behind the baffling. The result is that the avionics backup battery only lasts about two years when other Odyssey 680s last 5-8 years when installed aft of the baggage closeout.what have others done for excess heat? cowl flaps or vents?
>>
>>
--
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| | - The Matronics RV10-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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Robert J Jones
702-521-1840 |
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