Too Much Cooling?

[N890GF]

I'm 11 hours into phase 1 and I'm pretty sure I've completed break in several hours ago (oil consumption stabilized and I've not consumed any oil in the last 4 hours). I started to do some endurance and max range testing, and my question is if I'm over cooling my engine/oil. As a note: I don't have my fairings or wheel pants on the plane yet. Engine is a Superior IO-360-B1HD2 180hp 8.5:1 dual PMAGs & 3 blade MT Prop

The information below is just from the cruise portion of each flight, and they were performed at different altitudes (the hot day testing is for comparison).

Here are the parameters (with charts):

Cold Day Testing​

OAT (at altitude): 46F
GPS Altitude: 4500ft
CHTs:

• Cyl 1: 323.6
• Cyl 2: 318.6
• Cyl 3: 312.8
• Cyl 4: 336.2

EGTs: Peaked at 1407-1427 -> LOP between 1380 and 1409 (~20deg LOP)
Oil Temp: Decreasing from 172F -> 153F over 15 minutes of cruise
Fuel Flow: 7.3 GPH
Percent Power: 61% - 62%
TAS: 130kts

I did another flight a few weeks back when we had an unseasonal heat wave and OAT was between 95 and 105. Parameters from that flight for comparison

Hot Day Testing​

OAT (at altitude): 97F
GPS Altitude: 1500ft
CHTs:

• Cyl 1: 390.2
• Cyl 2: 390.1
• Cyl 3: 381.2
• Cyl 4: 386.6

EGTs: 1350-1380 (ROP)
Oil Temp: 199F
Fuel Flow: 12.3 GPH
Percent Power: 76% power
TAS: 147Kts

My question to the experts out there - do I need to do anything? Oil Cooler is attached to the #4 rear baffle, and I don't currently have any way to block air to it, but have looked into adding a shutter or some other valve.

 

[RNB]

I am not an expert.
What engine and cylinders?
What does you manual say for break in time?
If you are worried, why are you changing your break in?

 

[Desert Rat]

Is this an IO360? I don't see anything wrong with those numbers.

 

[N890GF]

Updated original post with engine info - Its a Superior IO-360-B1HD2 180hp 8.5:1 with dual PMAGs and a 3 blade MT prop

 

[Norman CYYJ]

Updated original post with engine info - Its a Superior IO-360-B1HD2 180hp 8.5:1 with dual PMAGs and a 3 blade MT prop

Those temps look good to me. Continue breaking in

 

[Mikeyb]

Hmmm
7.3 GPM should deliver 49 percent power on a IO360.
12.3 GPM should make 82 percent power.
The airspeeds seem low no? I have an RV8 and I would be going a lot faster at those power settings.
What was the MP and RPM.

 

[N890GF]

Hmmm
7.3 GPM should deliver 49 percent power on a IO360.
12.3 GPM should make 82 percent power.
The airspeeds seem low no? I have an RV8 and I would be going a lot faster at those power settings.
What was the MP and RPM.

23" 2300 for the cold day and 25.5" 2500 for the hot day. I also don't have my wheel pants and landing gear fairings installed. so I expect to see much lower airspeeds

 

[D-Dubya]

147 knots down low on a hot day and 199 degrees F oil temp without your pants on seems about right to me. We don't have all the engine parameters, but that doesn't seem out of line.

Van's says the gear leg fairings and wheel pants are worth about 12 knots in speed. A little more speed will bring the temps down a bit more.

 

[Mikeyb]

7.3 GPM is off the charts lean for 2300 RPM. Is 130K or even 142K at 4500 ft the right cruise speed for those planes?

 

[N890GF]

7.3 GPM is off the charts lean for 2300 RPM. Is 130K or even 142K at 4500 ft the right cruise speed for those planes?

i'm not sure how to interpret this? i was about 20 degrees lean of peak when i pulled back my mixture on this flight

 

[Mikeyb]

i'm not sure how to interpret this? i was about 20 degrees lean of peak when i pulled back my mixture on this flight

Probably you can ignore it. But I don’t think there is any way you can make 120 hp on 7.3 GPM. It might just be your fuel flow indication. There is no indication you have cooling problems.

 

[N890GF]

Probably you can ignore it. But I don’t think there is any way you can make 120 hp on 7.3 GPM. It might just be your fuel flow indication. There is no indication you have cooling problems.

at 23" and 2300 RPM with that fuel flow fluctuating between 7.3 and 7.4 my EFIS showed 61% power or about 109 hp. I think that seems about right? I do see 100% power on takeoff with about 16.4 GPH at 2700 RPM and 29" or so.

 

[dmattmul]

Recommend getting your wheel pants on and fairings. Besides better cooling phase 1 is about determining critical metrics and testing flight envelope. How can one do that with air speeds different by 12 knots? Congrats on current temps and speed, look good !

I like having an oil damper door on my parallel valve 540. Allows me to reduce CHT's in climb and get the OT to the 190 F range before I open it.

 

[N890GF]

Recommend getting your wheel pants on and fairings. Besides better cooling phase 1 is about determining critical metrics and testing flight envelope. How can one do that with air speeds different by 12 knots? Congrats on current temps and speed, look good !

I like having an oil damper door on my parallel valve 540. Allow me to reduce CHT's in climb and get the OT to the 190 F range before I open it.

Definitely agree, I'm not planning on exiting phase 1 until the fairings and wheel pants are on. But I'm having to much fun flying to stop and work on the plane. I guess I need to have some discipline still

 

[Mikeyb]

at 23" and 2300 RPM with that fuel flow fluctuating between 7.3 and 7.4 my EFIS showed 61% power or about 109 hp. I think that seems about right? I do see 100% power on takeoff with about 16.4 GPH at 2700 RPM and 29" or so.

I I spend too much time looking at charts. To get that efficiency you need specific fuel consumption of 0.4 lb/hr/hp which I didn’t know you could do but the internet says you can. Coupled with my experience flying an RV8 with wheel pants at that power setting burning 8-8.5 gph I would be going closer to 155K and looking at the two Lycoming charts I wondered if you were too far lean. Sorry

 

[dmattmul]

I I spend too much time looking at charts. To get that efficiency you need specific fuel consumption of 0.4 lb/hr/hp which I didn’t know you could do but the internet says you can. Coupled with my experience flying an RV8 with wheel pants at that power setting burning 8-8.5 gph I would be going closer to 155K and looking at the two Lycoming charts I wondered if you were too far lean. Sorry

Pretty close, 260 hp rated: 0.40(260*.59)/6.02= 10.2 GPH theoretical, probably could have gone a few more % LOP.



0.40(260*.63)/6.02= 10.88 GPH, again probably could have gone a little more LOP but like the TAS !



IO390 non EXP: 0.40(210*.64)/6.02= 8.93 GPH

 

[Desert Rat]

A couple of reasons that justify (at least to me) why a guy might want to fly the first couple of flights without wheel pants is that in my case I hadn't ever taxied the plane and the brakes were't seasoned. It was nice to not have to worry about trapping all that heat in the pants during that first taxi. It was also nice to know that the plane flew straight without that stuff hanging of off it, so that when I put them on later if the ball wasn't in the middle it would be pretty obvious what was causing it.

Honestly, it was also because I didn't have them done yet and I was just sick of fiberglass work at that point.

My first flight was with the gear leg fairings but no pants, and yeah, when I added them a couple of flights later I picked up around 7-8 kts I think that Vans is pretty much spot on when they say all the fairings down there are good for about 12 kts.

 

[DanH]

George, your temperatures are fine for now. Bite the bullet and finish the airplane so you can see what you really have.

The decent cruise performance figures are found between 7500 and 10500. They're all slow down low.

Honestly, it was also because I didn't have them done yet and I was just sick of fiberglass work at that point.

An honest man.

Too late for George, but wheel pants are best done in the comfort of the home shop. The -8 and all the models with motor mount legs can be jigged up and completed early in the game. I've done 'em on my knees in a hangar, and the difference is night and day.