Kitplanes Article-Sam James Cowl

My wife Amy wrote about the latest mod we have made to our SJ cowl and plenum setup. I have done some local and cross country flights and are happy with the results.
My biggest problems before the new plenum and larger rings was I could not do a quick turn in warm conditions that we have in FL. without climbing out at a fast airspeed 140-150 kias with full power and keep #5 and #6 CHT under 400f and oil temp under 220f.
After a stop with 100 OAT, we were able to climb at 130 kias and keep the CHT's around 390f and the oil at 205f. At cruise at 8000-10,000' ROP or LOP I could
keep CHT's 380-390f and oil temp at 195f, burning 16gal/hr ROP at 184 ktas and LOP at 11.5 gal/hr at 173 ktas.
As Amy stated, we have louvers on the bottom and sides of the cowl and have opened up the bottom of the cowl for more exit area. It is very important to seal around the plenum and the engine, and have a smooth transition from the rings to the ramp for the baffles.
I have 1 slick mag and 1 EIS EI. I feel the EI is a must for running LOP smoothly.
Sam is all about helping out if ya have a problem so give him a call; and call or email me if ya have any questions. Blue Skys Barry

CHT and oil temp

I too have been battling high CHT and oil temps since OAT have gotten higher with my SJ cowl and plenum. I cancelled our family trip to the Bahamas with Jim Baker and group because flying in hotter OAT (90) caused my oil temp to peak out at 244 before calling off the trip.

I have changed out the original 5" cooling inlet cowl with Wills' new 6" inlet cowl and just finishing up re-locating my oil cooler, (SW 10631S) directly behind #6 and will hopefully be back in the air this week to continue flights and testing cooling of CHT's and oil.

I give Will and Sam James praise and credit for their attention, concerns and efforts to help with all of the RV10 builder with issues. Most of the installations and HP are different which makes solving this problem a challenge and less science more like black magic.

I read the article in Kitplanes yesterday and I hope that my troubles will be behind me. I have a Barrett cold air, 9:1 pistons that dyno'd at 275 without the dual Lightspeed installed. I have 77 hrs on my 10.

Kenny Gene
RV10-484TC;77 hrs
RV7a-294TC;650 hrs

Confused About the Issue

Barry,

I have been watching the issue as I am also planning on a rebuilt IO 540 C4B5. People with the IO 540 D4B5 do not seem to have as many issues with temps. Is my perception correct? Does anyone know why? Does the roller cam not generate as much heat? Seems logical that less friction generates less heat. Is it significant?

Amy had written a previous article about the overheating issue and I understood from that article that the Airflow oil cooler had corrected the problem, or at least had made large improvements. In the latest article the Airflow oil cooler was not mentioned, just extra vents. I was planning on substituting the Airflow cooler for the Vans but do not understand it not being mentioned in her latest article. Did you find that the airflow cooler helped the temps?

Is the SJ cowling contributing to the overheating problem? There seems to be some pattern between the SJ cowl and higher temps. Is my perception true about the SJ cowling causing high temps correct and you are just not pointing fingers?

Do you know if the new SJ plenum is only designed to be installed with the SJ cowl or can it effectively be installed on the Vans cowl? I could not figure for sure the intended application from the article, RV-10 or RV-10 with SJ cowl owners.

I thought I had a plan to control the temperature issue with the Airflow cooler, stay with the Vans cowling, care with the baffling, and just the two louvers, but the latest article confused me.

Please give a little more insight.

Thanks,
Eulice Curington
RV-10 Fuselage #40596

If SJ issue, then RV10

My cooling on my 7A with SJ cowl and plenum is too good. Dick Martin's RV8 has smaller than standard "holes". I notice all the posts above are for the -10. Just trying to clarify the issue. I have no answers about the -10.

SJ Cowl

Hi Eulice, we still have the Airflow oil cooler and it does help to lower temps. My problem was cooling after a quick turn and a heat soaked engine; with the new plenum and larger intakes I can now control oil and CHT temps. The SJ plenum is formed to fit the SJ cowl and to use it with Van's cowl would require a lot of rework. I think you have a good plan to control the temperature issue with the Airflow cooler, stay with the Vans cowling, take care with the baffling, and just the two louvers. I went with the SJ cowl because at the time I built the Van's fiberglass parts were pretty bad, and I wanted to try for some better performance. If I was building today I would go with your plan. Blue Skys

I have a rebuilt IO-540-C4B5, stock Van's cowl, and a cooling plenum from Steve Dinieri at iflyrv10.com. I also have the 2006X Airflow oil cooler. I had no cooling problems at all for the first 200 hours. (I also have the Flightline AC air conditioning). At about that time, I had a problem with the AC compressor mount and elected to install a new and different compressor/alternator mount from Flightline. That required reworking my front ramps. Now, I still have very acceptable CHT's (low 300's in cruise and mid to upper 300's in climbs to altitude in Florida heat) My oil temp is not quite as good as it was, but is still OK. A couple of days ago, after a quick turn at KFPR on a very hot day, I saw 220 degrees during the climb. Once I leveled off at 9000', oil temp immediately dropped to 195 and was at 185 within a few minutes. Prior to the inlet change, I would not see the higher oil temps during climb. I am sure this is due to the compressor and it's mount interrupting some of the airflow in the left inlet.
Long story, but my main point is that I had very nice CHT and oil temp right out of the chute with my rebuilt C4B5, stock Van's cowl, cooling plenum from iflyrv10.com, 2006X oil cooler, and the stock Van's louvres on the bottom of the cowling.
I agree with Barry. Your plan sounds fine. I would not install extra louvres unless flight test shows the need for them.

Thanks for the Input

I appreciate the experience and willingness to share knowledge this forum offers.

Eulice