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Any success with cold air plenum on RV-10

F

falcon900guy

Well Known Member
i'm not there yet, but i am looking around for successful cold air plenums on RV10's. why aren't there many out there, and what is the challenge with a cold air plenum on an RV10?

thanks for the input
 
Because if you get the standard baffle right, the downgrade to any plenum is ??well?.a downgrade.

:)
 
Cold air plenum a

Those that I have worked on just don't fit. You have to remake them. They offer no better cooling than baffles and they restrict access to the top of the engine. Plus you get to pay lots of $$$ for no benefit. Just one guys opinion.

Gary
 
What Oz said

Because if you get the standard baffle right, the downgrade to any plenum is ??well?.a downgrade
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Put another way, when the wheel is round you can't make any rounder.

Standard baffles properly installed work very well on the RV-10.
 
Gary 40274 said:
Those that I have worked on just don't fit. You have to remake them. They offer no better cooling than baffles and they restrict access to the top of the engine. Plus you get to pay lots of $$$ for no benefit. Just one guys opinion.

Gary
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I have a plenum on my RV-8, and while it works very well, it is a pain to get to the top of the engine.

When I build a 10, it'll be with baffles. Plenums, while they look cool are just a lazy alternative to well done baffeling.
 
Sig600 said:
Plenums, while they look cool are just a lazy alternative to well done baffeling.
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Unless, of course, you have a really well done plenum....but that's not going to be a lazy man's path, as there doesn't appear to be any worth buying.

Returning to the OP's questions...

There is no wide selection of readily installed plenum lids for any model.

The design/build challenge is, in addition to the usual best practices, two-fold. No1 is coupling to the cowl inlet in a way that seals 100%, and does not screw up the conversion of dynamic to static pressure. No2 is working out a good seal around the 540's dipstick.
 
falcon900guy said:
i'm not there yet, but i am looking around for successful cold air plenums on RV10's. why aren't there many out there, and what is the challenge with a cold air plenum on an RV10?

thanks for the input
Click to expand...

It is very hard to quantify "success".

Just data from my experience.

Took approx. 200+ hrs to design/build additional

Appears to have gained several knots (airplane cruises 178-180knots TAS at 10,000msl on 11.8-12.0 gph with a parallel valve IO-540) There were several other mods made during the build to help the efficiency so like i said, its hard to quantify.

CHT is running 370-390 avg during cruise and no more than 410 on a long climb hot day with a heat soaked engine.

Personalty I think it was a success.
 
Not saying you shouldn't try it, after all even the RV-10 is an experimental aircraft.
If you are looking to improve cooling it'll be hard to beat the stock installation.
CHT is running 370-390 avg during cruise and no more than 410 on a long climb hot day with a heat soaked engine.
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I don't see Weasel's temp out of line but 200 hours of extra work to get temps that are almost 100F higher than a good stock installation is something to think about. Not to mention the restricted access to the top of the engine.

My Cylinders are probably too cold and if I closed up the exit area I'd probably pick up the extra 2 or 3 knots that you seem to have over mine.

BMP%25202.jpg
 
It's definitely not the lazy man's alternative. It took me a lot of time to get that sucker to fit. It's far from just bolting it on.
Sam James actually recommends rolling your own aluminum baffles to go with it. More work. As Dan mentioned you need a way to seal off the dipstick. Then the plenum inlet rings don't line up with the cowl inlet rings...
Then it's not tall enough in the back so your oil cooler hose will be sucking hot air from between the #6 cylinder fins.

A lot of people who have the James cowling+plenum did it because of installing a high compression engine with a cold air sump, (maybe even ceramic coated Forsling exhaust pipes) which does not fit in the standard cowling. Those engines produce 40+ more hp (depending on who you ask), and a bunch more heat, so you cannot really compare that setup to standard engines with standard baffles.

I have the James cowl+plenum, the bigger cowl intake rings, standard D4A5 engine. I got sucked into it cause I like the look of the round cowl inlets.
I'm in Florida and I don't have heat issues.
My oil temps are in the 180s in cruise, and CHTs in the low 300s. So I don't think it's a downgrade as has been said before but it's definitely a ton more work for just looks...

Lenny
 
Lenny Iszak said:
It's definitely not the lazy man's alternative. It took me a lot of time to get that sucker to fit. It's far from just bolting it on.
Sam James actually recommends rolling your own aluminum baffles to go with it. More work. As Dan mentioned you need a way to seal off the dipstick. Then the plenum inlet rings don't line up with the cowl inlet rings...
Then it's not tall enough in the back so your oil cooler hose will be sucking hot air from between the #6 cylinder fins.

A lot of people who have the James cowling+plenum did it because of installing a high compression engine with a cold air sump, (maybe even ceramic coated Forsling exhaust pipes) which does not fit in the standard cowling. Those engines produce 40+ more hp (depending on who you ask), and a bunch more heat, so you cannot really compare that setup to standard engines with standard baffles.

I have the James cowl+plenum, the bigger cowl intake rings, standard D4A5 engine. I got sucked into it cause I like the look of the round cowl inlets.
I'm in Florida and I don't have heat issues.
My oil temps are in the 180s in cruise, and CHTs in the low 300s. So I don't think it's a downgrade as has been said before but it's definitely a ton more work for just looks...

Lenny
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Ok maybe lazy was a bit harsh, but I would still contend getting a plenum to fit, vice building proper well sealing baffles, the former is easier. I've seen more cooling problems and discussions though for builders using plenums however.

As a data point, at 1500' @ 75 deg OAT, running 25/2300 @ 7.5-8 GPH I see 145kts IAS with CHTs running 295-320 on the hottest. This is a 10.5:1 IO-360 parallel valve.

I don't know that I can attribute that to the plenum I have, and I think it would run cooler with an equally well sealed baffle job as the volume is almost double.

As you and Dan have alluded to, it really comes down to the builder. Either can have problems.

Plenums do look cooler though :D

15plx1j.jpg
 
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