Carbon sump++ for 320/360 engine.

[N360DF]

Folks, I am looking into making my own oil sump and air box / pipes in carbon. However my biggest concern is the carbon less heat transfer compared to aluminum. 10x less. Or even more practical seen. Cools down the oil 10x less efficient. I planning to make storage for 6-7 qt. So less oil mass to carry and heat/cool. I am not the best theory dude, so I would be very happy to hear pros and cons. I guess its the matter of how much the sump normally contribute for cooling.

Thanks for all feedback!

 

[BH1166]

Folks, I am looking into making my own oil sump and air box / pipes in carbon. However my biggest concern is the carbon less heat transfer compared to aluminum. 10x less. Or even more practical seen. Cools down the oil 10x less efficient. I planning to make storage for 6-7 qt. So less oil mass to carry and heat/cool. I am not the best theory dude, so I would be very happy to hear pros and cons. I guess its the matter of how much the sump normally contribute for cooling.

Thanks for all feedback!

What’s your purpose for this? Looking for a gain for your efforts that Im obviously missing. Con… the knows and unknowns , pros I don’t see one.

 

[Scott Hersha]

I think this was done before. My former hangar partner (RV8) had an IO-360 with a composite sump. I think it was a Superior engine - new. His sump developed cracks, and he had to replace it with a standard metal one. Might be worth researching.

 

[N360DF]

What’s your purpose for this? Looking for a gain for your efforts that Im obviously missing. Con… the knows and unknowns , pros I don’t see one.

For the sump part, weight and shape who better fit my install

For the airbox/tubes part: weight, shape, more air and tapered tuned pipes.

 

[N360DF]

I think this was done before. My former hangar partner (RV8) had an IO-360 with a composite sump. I think it was a Superior engine - new. His sump developed cracks, and he had to replace it with a standard metal one. Might be worth researching.

Yes it was years ago made in some plastic, this was not good.
This want happen with carbon. But thanks for info.

 

[Walt]

I think this was done before. My former hangar partner (RV8) had an IO-360 with a composite sump. I think it was a Superior engine - new. His sump developed cracks, and he had to replace it with a standard metal one. Might be worth researching.

A backfire would actually blow the sump off

 

[nzrv8]

I would not use a carbon sump for various reasons - heat transfer being the main one, and you would need to look into any strength component that the standard sump adds to the crankcase. I think you mentioned reduced oil capacity? You don't want to reduce the oil capacity - this will only add to your oil cooling issues.

Carbon intake tubes and airbox sounds like a cool project though!

 

[David Paule]

Might be worth taking a look here. Not carbon but it works and has already been developed.

Carbon can offer high thermal conductivity if done with that in mind. But if done with structural considerations foremost, perhaps not. My own take is that you'd be far better off buying a set of components that fit and work well than attempting to develop your own. The development time will far exceed any achieved value - my opinion, of course.

Dave

 

[hgerhardt]

I think using carbon fiber reinforced plastic (CFRP) is a great idea, but lots of work. The Superior plastic intake plenum is an entirely different animal, and them potentially blowing apart was foreseeable. Dave Anders made a CFRP intake plenum and wrote about it in Kitplanes.

Besides weight savings, a new sump design could be to build a dry sump with an external tank like a Rotax uses. That could be combined with an inverted oil system as well. That way the intake plenum could be mounted higher up, making the engine more compact height-wise if that's helpful for packaging. As to heat transfer out of the sump with CFRP vs aluminum, doubt that would make much difference. There aren't any fins on the Al sumps to aid heat transfer anyway.

The "10x less" heat transfer of CFRP vs Al is a good thing for the intake plenum and helps keep the charge cool. One thing I'd do is add a blow-off valve to the plenum in case of backfire, or make the laminate very thick as Anders did on his plenum. You'll also need to make the intake tubes-to-plenum joints flexible as the cylinders will grow much more than the CFRP.

I designed and made a CFRP intake manifold for my GTO back in the 90's and it's still holding up great.

 

[N360DF]

A backfire would actually blow the sump off

Yes I think it did happen! Known as a good learning.
Carbon is other story and pressure valves is possible to add.

 

[N360DF]

I would not use a carbon sump for various reasons - heat transfer being the main one, and you would need to look into any strength component that the standard sump adds to the crankcase.

The sump is not playing a part of the role as strength to crankcase.

The concern about the heat transfer is one reason I bringing this up,
Possible it would be better values. All depends ?

I think you mentioned reduced oil capacity? You don't want to reduce the oil capacity - this will only add to your oil cooling issues.

Why will it add to cooling issues ?

Carbon intake tubes and airbox sounds like a cool project though!

Thanks!

 

[N360DF]

Might be worth taking a look here. Not carbon but it works and has already been developed.

Carbon can offer high thermal conductivity if done with that in mind. But if done with structural considerations foremost, perhaps not. My own take is that you'd be far better off buying a set of components that fit and work well than attempting to develop your own. The development time will far exceed any achieved value - my opinion, of course.

Dave

Thanks for your reply! I know about the Sky Dynamics system. Very nice, but as I understand not available and non sold in years.
However this will not suit my needs, but this is actually one system I have used in my brainstorming.

I know Dave used the system and runners from SD but made the airbox custom in carbon for his project. Very interesting projects.. Loads of respect for his project!

Regards thermal HT and strange, both may be able to get. Same systems as carbon brake disk.. ($$)

 

[Southern Pete]

You are making a lot of statements that are based on supposition rather than facts. People are trying to help you but you're not listening. Sky Dynamics equipment is available, the lead time might be quite long but probably not as long as building your own components from cloth and resin.

 

[N360DF]

I think using carbon fiber reinforced plastic (CFRP) is a great idea, but lots of work. The Superior plastic intake plenum is an entirely different animal, and them potentially blowing apart was foreseeable. Dave Anders made a CFRP intake plenum and wrote about it in Kitplanes.

Besides weight savings, a new sump design could be to build a dry sump with an external tank like a Rotax uses. That could be combined with an inverted oil system as well. That way the intake plenum could be mounted higher up, making the engine more compact height-wise if that's helpful for packaging. As to heat transfer out of the sump with CFRP vs aluminum, doubt that would make much difference. There aren't any fins on the Al sumps to aid heat transfer anyway.

The "10x less" heat transfer of CFRP vs Al is a good thing for the intake plenum and helps keep the charge cool. One thing I'd do is add a blow-off valve to the plenum in case of backfire, or make the laminate very thick as Anders did on his plenum. You'll also need to make the intake tubes-to-plenum joints flexible as the cylinders will grow much more than the CFRP.

I designed and made a CFRP intake manifold for my GTO back in the 90's and it's still holding up great.

View attachment 52686 View attachment 52687

Thanks for your detailed feedback..

You have all the thoughts what I want try achieve except the inverted,
however I think it should bee easy added if wanted
One of the main drivers is to get the intake higher up..

The system will two pieces for more easy changes and prototyping.
And even the sump may be other material than airbox..
I did not think about it actually that its HT for normal resin is good
for the airbox.. thanks!

Regards the cooling in sump, I would believe its some but I am not sure.
Is like you say, the are not fins on. Except the sky-dynamics. They have
fins outside sticking up in the inside bottom.. But again this my biggest
concern but may be overcome with the right resin.
But possible its not needed.. Or maybe better for some.. all depends
of the cowling ?

If I go for carbon sump, I will design for weight reduction but pressure tested
for backfire..

I did not understand quite with what you mean with the cylinders will grow much more.. Do you mind explain ?

You manifold for your GTO looks badass.. a lot of kudos.

Best regards

 

[hgerhardt]

Thanks for your detailed feedback..

You have all the thoughts what I want try achieve except the inverted,
however I think it should bee easy added if wanted
One of the main drivers is to get the intake higher up..

The system will two pieces for more easy changes and prototyping.
And even the sump may be other material than airbox..
I did not think about it actually that its HT for normal resin is good
for the airbox.. thanks!

Regards the cooling in sump, I would believe its some but I am not sure.
Is like you say, the are not fins on. Except the sky-dynamics. They have
fins outside sticking up in the inside bottom.. But again this my biggest
concern but may be overcome with the right resin.
But possible its not needed.. Or maybe better for some.. all depends
of the cowling ?

If I go for carbon sump, I will design for weight reduction but pressure tested
for backfire..

I did not understand quite with what you mean with the cylinders will grow much more.. Do you mind explain ?

You manifold for your GTO looks badass.. a lot of kudos.

Best regards

You're welcome!

Definitely make the sump and plenum as two separate parts. Would be extremely difficult/impossible to make in one piece with simple tooling.

As for material, I used Hysol EA 9396 epoxy resin and vacuum bagged every layup. EA 9396 can be room temperature cured with 350F working temp. For the CF cloth, I used a fairly heavy twill weave, which allows good draping over complex geometry, and the weave is really pretty to look at later.

I wouldn't worry about heat transfer for either part. The low heat transfer of CFRP is good for the intake plenum to keep the charge cool and for the oil sump it won't matter since you're going to do the cooling with a heat exchanger. One thing you'll have to figure out is the oil passageway for the oil pump inlet as well as the sump screen. Maybe make a machined threaded insert to hold the screen plug and bond it into the finished laminate with EA 9394 epoxy (a thick, filled version of EA 9396). Or could do a stainless tube with an external coarse screen and a fitting to mate with the accessory housing where the oil passageway connects.

The backfire valve is only possibly necessary in the intake plenum, not the sump.

As to the cylinders growing: the cylinders/heads are metallic and will expand in length when hot. CFRP expands very little in comparison. So, you just need to make the intake runners separate and connect to the sump with short sections of hose, like Lycoming already does with the parallel-valve engines.

Thanks about the GTO... it's still entertaining to stand 10' from the car with the hood up at a car show and watch people do double-takes when they see the manifold. 25 years after I built it it's still pretty exotic.