mburch

mburch

Well Known Member
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Hi folks,

Although I don't want to rehash the many previous discussions on the issue of oil cooler mounting location, I wanted to throw out some photos of one proposed location that will fit in my RV-7 and see if anybody has any thoughts.

I happen to have a great big Stewart Warner 8432R cooler already, and I don't think I'm going to be able to be able to mount it on the baffle (although it has been done before). Since I'm building a taildragger, I've got extra engine mount structure up front, which complicates where I can put that giant oil cooler, and rules out any locations on the firewall. But here's some bad cellphone photos of one possible location on the engine mount - click to see full size:





The roll of duct tape in the last photo is 4 inches in diameter, showing that I have room for 4" SCAT hose and a diffuser here. I can probably attach four corners of the mounting flanges to the engine mount with adel clamps and aluminum angle. The bottom of the oil cooler is about 3" from the #4 exhaust - too close? Anything else I should watch out for here?

Another possible option, of course, is to call up Pacific Oil Cooler and try to trade this thing on a smaller 8406R, which will fit on the baffle. That is definitely something I'm thinking about!

thanks,
mcb
 
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Well Matt, i know you've done your homework here already, and have probably read more about RV oil cooler installations than I have, so I'll just give you my take on it. Remember that most of the time, when you come to a forum and read about the issues folks have with something like oil temperature, you are reading about the PROBLEMS that folks have - which are completely valid by the way, for their installation, not putting them down at all. But you don't see anyone posting "I flew with my stock installation and had no issues!" Despite the fact that a huge number of RV's fly with the stock setup without issues. I have found that the stock FWF kit cooler, mounted on my rear baffle, gives me adequate cooling about 95% of the time - the only time I get hot is during extended slow flight on a hot summer day, or climbing out of Phoenix after a quick-turn fuel stop with OAT's above 100 degrees. During those conditions, yes, the cooling is marginal, so I have to adapt - stop flying slow or shallow my climb rate for instance.

The issues with a custom installation, of course, is determining in advance if you're going to get better cooling or not - plus all of the unknowns of vibration, mounting issues, and the many little bits and pieces you'll have to fabricate. Are those time sinks and the unknowns that you might encounter worth the effort to improve cooling above stock for those times you need it? Depends on how hot it gets where you live, and your need to operate in the hot corners of the envelope.

I have found that Van's design is usually a pretty good place to start and go fly. Most of the time, you can modify later. You might just check on trading for a cooler that will fit....

Paul
 
Ironflight said:
Well Matt, i know you've done your homework here already, and have probably read more about RV oil cooler installations than I have, so I'll just give you my take on it. Remember that most of the time, when you come to a forum and read about the issues folks have with something like oil temperature, you are reading about the PROBLEMS that folks have - which are completely valid by the way, for their installation, not putting them down at all. But you don't see anyone posting "I flew with my stock installation and had no issues!" Despite the fact that a huge number of RV's fly with the stock setup without issues. I have found that the stock FWF kit cooler, mounted on my rear baffle, gives me adequate cooling about 95% of the time - the only time I get hot is during extended slow flight on a hot summer day, or climbing out of Phoenix after a quick-turn fuel stop with OAT's above 100 degrees. During those conditions, yes, the cooling is marginal, so I have to adapt - stop flying slow or shallow my climb rate for instance.

The issues with a custom installation, of course, is determining in advance if you're going to get better cooling or not - plus all of the unknowns of vibration, mounting issues, and the many little bits and pieces you'll have to fabricate. Are those time sinks and the unknowns that you might encounter worth the effort to improve cooling above stock for those times you need it? Depends on how hot it gets where you live, and your need to operate in the hot corners of the envelope.

I have found that Van's design is usually a pretty good place to start and go fly. Most of the time, you can modify later. You might just check on trading for a cooler that will fit....

Paul
Click to expand...

Matt is coming off a Subaru adventure where oil cooling was an issue on most every flight except in the dead of winter. Having come down the same road, I did not want a repeat of that problem with the Lycoming.

FWIW my 8432R is mounter up higher, horizontal, with a 4" scat tube robbing air from #4 aft baffle, and provides excellent cooling in any weather. I have not seen 200F oil temp yet. This also helps keep CHT's cooler on a hot day.

ls it overkill? Perhaps, but it does provide reliable oil cooling any day of the year.
 
Paul - Excellent recommendations, as always. I almost certainly wouldn't even be thinking about an alternate installation except that due to unforeseen circumstances I just happen to have the bigger oil cooler already sitting here, and it will cost me a nonzero amount to swap it out. But since I do have it already, I believe I will spend a day and see what kind of mounting arrangement I can come up with... and then it's likely I'll end up either heeding your sensible advice anyway, or wishing I had. :)

David - Good to hear from you again, hope you're doing well. You're not kidding, with those engines we had, the oil/coolant temps only had two positions in the summertime: "off" and "overheat". I'd love to see a picture of your cooler installation, if you have one handy you can post or email.

mcb
 
I don't think there is any issue to remote mounting the cooler as long as it is well thought out.

Other have commented good results with a 4" scat coming off the baffle as you plan to do. Use a nice smooth hose route, to a good transition duct, make an outlet duct that take it to the cowl exit and I think things will work out fine.
 
I have not seen 200F oil temp yet.
Click to expand...

I have. But I had to close the Van's oil cooler -- slider door to do it.

My cooler is the stock configuration.... behind the #4 baffle.

L.Adamson --- RV6A/ Lyc 0360
 
David-aviator said:
Here is a view from the top. The whole thing was made from scrap aluminum except the 4" scat tube flanges came from Van's. (same ones used with the 10)

Click to expand...

Thanks David - gives me something to compare to. Too bad the taildragger has all those extra tubes in that location, it looks like a dandy place for an oil cooler!

mcb
 
I give up

Okay Paul, you were right... I spent a day trying to figure out how to get it to fit, but there's too much stuff in the way. It wouldn't be too hard to mount it on the firewall in an A-model, but the extra tubes in the taildragger are in the way, plus my engine control cables are taking up the only other spot on the firewall it could fit.

So, anybody want to buy an oil cooler? :)

mcb
 
I've seen some pictures of people mounting the cooler on the right side on the firewall instead of the left side. I've looked at doing that on my -8 but decided to improve the baffles first. Just getting the front sealed up better lowered CHTs and oil temp a lot so I'll keep working on the baffles for a while.

As a data point, my cooler is on the left rear baffle with a 1/4" spacer. This weekend I climbed to 7500' from Midland TX in 85F surface temperature. About 1000 fpm for the first couple of thousand feet and then 500 fpm cruise climb and oil temp topped out at 195.
 
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