TravisHamblen
Active Member
I have received a bunch of requests for performance of my IO-390 from Barrett Precision Engines. I'm not a professional test pilot, and the data that follows was not meant to be a comparative analysis between ROP and LOP. The data below is just to samples I took during a recent flight test. As far as Barrett Precision Engines go, I would not buy an engine anywhere else. I can call them at anytime and get on the spot advice and answers from the top! Although I haven't needed any work or modifications, I know that with a phone call they will 100% stand behind the engine and do whatever needs to be done to make sure I am 100% satisfied. So I hope that answers your questions about doing business with the Barrett family.
I started off with the Van's provided Niagara 20002A cooler, which is great for a 160hp engine, not so great on 215 HP!! At 6.4 hours I upgraded to a much beefier cooler, still mounted on the back of the baffles and everything is just perfect! With the new oil cooler (Stewart Warner 10599R) I have NO oil temp problems, everything is just perfect. I experimented with leaning to best power setting and also LOP operation. LOP obviously results in MUCH better operating conditions; I can dial the engine in to almost perfect operating conditions! I have Airflow Performance fuel injection & Dynon EFIS & EMS with CHT and EGT probes on all cylinders. I have always run carbureted engines, so this ability to extremely fine-tune all the settings to almost down to a degree of change is just amazing!
If you are looking at the performance numbers, keep in mind that with the fairings installed I would get about 20 knots better performance on the RV-7A. Below are the results:
Test #1 (ROP):
47 degrees F OAT @ altitude
8600 MSL
9590 Density Alt
155 knots corrected TAS (NO FAIRINGS AT ALL)
2410 RPM
21.2" MP
1485 was approx peak EGT
Peak EGT at this setting results in 8.8 GPH
I leaned to 50 degrees ROP which results in 10.3 GPH
CHTs were 391, 393, 408, 353
EGTs I didn't record EGTs for some reason
Oil temp 198F
Oil pressure 72
Test #2 (LOP):
52 degrees F OAT @ altitude
6280 MSL
7100 Density Alt.
144 corrected knots TAS (NO FAIRINGS AT ALL)
2300 RPM
23" MP
I leaned to 50 degrees F LOP which results in 8.7 GPH
CHTs were 366, 367, 369, 334
EGTs were 1435, 1410, 1412, 1423
Oil temp 185F
Oil pressure 72
Obviously I could run much higher power settings such as increasing the RPMs up to 2600 or so at altitude, but I didn't have time to get into experimenting with these settings very much. I did check, and at 6500 MSL with 23" MP and 2700 RPM (very briefly) I saw 165 corrected KTAS (with no fairings). The speeds all seem right, with fairings it looks like I will see a top speed of 215MPH. But the beauty of the 390 is the climb!! I climb out at 100 kts and usually see at least 2400 fpm. At best rate of climb I would guess that I will see 3000 fpm, but I haven't got to that part of the flight testing yet. Oil consumption seems okay, but I don't have definitive results on that yet. After replacing the oil cooler at 6.4 hours, I went ahead and changed the oil, so that I would have pristine oil that has never been ran at high oil temps. So far it looks like I have burned/lost about 1/2 a quart after 3.5 hours of tach time. So probably about 1/2 a quart in 4.2 hobbs hours or so, I'm thinking this is normal for the break in period of the engine.
In the near future I will start doing some comparative testing and be a little more scientific in the way I perform the test and record the data. I'll report back with the more scientific data in the next couple weeks. In past testing I was just happy to finally be flying, but now I want to answer a bunch of my own questions about performance and do some apple to apple comparisons of LOP/ROP for range and such. I hope this helps you guys on the fence about the IO-390, if not keep your eyes open for my next data sampling; it may cause you to take the IO-390 plunge!
Travis
RV-7A w/ 10.2 hours on the Hobbs!
I started off with the Van's provided Niagara 20002A cooler, which is great for a 160hp engine, not so great on 215 HP!! At 6.4 hours I upgraded to a much beefier cooler, still mounted on the back of the baffles and everything is just perfect! With the new oil cooler (Stewart Warner 10599R) I have NO oil temp problems, everything is just perfect. I experimented with leaning to best power setting and also LOP operation. LOP obviously results in MUCH better operating conditions; I can dial the engine in to almost perfect operating conditions! I have Airflow Performance fuel injection & Dynon EFIS & EMS with CHT and EGT probes on all cylinders. I have always run carbureted engines, so this ability to extremely fine-tune all the settings to almost down to a degree of change is just amazing!
If you are looking at the performance numbers, keep in mind that with the fairings installed I would get about 20 knots better performance on the RV-7A. Below are the results:
Test #1 (ROP):
47 degrees F OAT @ altitude
8600 MSL
9590 Density Alt
155 knots corrected TAS (NO FAIRINGS AT ALL)
2410 RPM
21.2" MP
1485 was approx peak EGT
Peak EGT at this setting results in 8.8 GPH
I leaned to 50 degrees ROP which results in 10.3 GPH
CHTs were 391, 393, 408, 353
EGTs I didn't record EGTs for some reason
Oil temp 198F
Oil pressure 72
Test #2 (LOP):
52 degrees F OAT @ altitude
6280 MSL
7100 Density Alt.
144 corrected knots TAS (NO FAIRINGS AT ALL)
2300 RPM
23" MP
I leaned to 50 degrees F LOP which results in 8.7 GPH
CHTs were 366, 367, 369, 334
EGTs were 1435, 1410, 1412, 1423
Oil temp 185F
Oil pressure 72
Obviously I could run much higher power settings such as increasing the RPMs up to 2600 or so at altitude, but I didn't have time to get into experimenting with these settings very much. I did check, and at 6500 MSL with 23" MP and 2700 RPM (very briefly) I saw 165 corrected KTAS (with no fairings). The speeds all seem right, with fairings it looks like I will see a top speed of 215MPH. But the beauty of the 390 is the climb!! I climb out at 100 kts and usually see at least 2400 fpm. At best rate of climb I would guess that I will see 3000 fpm, but I haven't got to that part of the flight testing yet. Oil consumption seems okay, but I don't have definitive results on that yet. After replacing the oil cooler at 6.4 hours, I went ahead and changed the oil, so that I would have pristine oil that has never been ran at high oil temps. So far it looks like I have burned/lost about 1/2 a quart after 3.5 hours of tach time. So probably about 1/2 a quart in 4.2 hobbs hours or so, I'm thinking this is normal for the break in period of the engine.
In the near future I will start doing some comparative testing and be a little more scientific in the way I perform the test and record the data. I'll report back with the more scientific data in the next couple weeks. In past testing I was just happy to finally be flying, but now I want to answer a bunch of my own questions about performance and do some apple to apple comparisons of LOP/ROP for range and such. I hope this helps you guys on the fence about the IO-390, if not keep your eyes open for my next data sampling; it may cause you to take the IO-390 plunge!
Travis
RV-7A w/ 10.2 hours on the Hobbs!
