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goosepool

Member
I have just got my new 4 airborne after 9 years of building (flatpack no P/P skins version).

I have fitted a new Superior XP-IO 360 and because the 4 is tightly cowl'd I was wondering about EGT, Oil and cylinder head temps. What sort of temp ranges should I expect to see in the 4.

Obviously with only 5 hours on a new engine she will be a little tight to start with so I need to watch the temps evan more closely. Has anyone crunched the numbers?

Happy landings

Stan
 
Temp 2

Wow that was quick, thanks for your prompt reply.

My cooler is stuck on the baffles at the rear of #4 cylinder.

I live in the northeast of England (35 miles north of York). We don't get very good weather here (ever). 07 has been the coldest year on record in our neck of the woods, with serious flooding, semi perpetual x winds and cool with it. Do you remember the film "The Day after Tomorrow"? I think they must have shot that in my home town (Darlington). It must have saved them having to spend a whole load on special effects.
We usually get 9 months of winter here, followed by 3 months of bad weather, compared with London, some 200 miles to the south, where it is usually sunnier, calmer and much warmer (often +10 to15 degrees warmer in the summer). I have a question about global warming -WHEN!

Sorry about that. I can't miss any chance to bitch about our lousy weather.

Seriously, you can count on one hand the number of real hot sunny days
we get in a year, so that will give you some idea of my flying environment.

Incidently, can you tell me what flap positions you use and for what. I have the Vans autoflap system, fixed at 10, 20 and 40 degree auto settings. Due to a C/S prop it would seem that full flap could be a real option for landing. In the UK an average strip could come out at around 600 metres (or less), so three pointers are the usual arrival technique, although I am based at an international Airport with a 7,300ft hard runway. The airfield itself is 120 ft above sea level.

I have little experience yet as MUMY only flew for the first time on October 1 and you guessed it, the weather has not been kind so I havn't done much, due to work commitments.

My 4 came out at 1117lbs empty weight as I have stuffed every aeronautical gadget known to man on it (fast tourer), but the C of G is in the right place, just aft of the forward limit. So,I can stuff anything I like in the back and not come even close to the aft limit. My only problem is gross weight. My measured top speed at 2,000 feet, 2700 x 27" (due to cloud cover) came out at 186kts
(214mph GPS).
Any tips on taming the beast would be well received.

happy landings
Stan

 
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Too hot to handle?

I test flew my 0-320 powered RV4 in the 95+ degeree heat of LA (lower Alabama) back in 96' and pegged all the needles. My oil ran 245, cyllinders 380+. There was no "RV list" or Doug Reeves site back then so I played around with my baffling, oil cooler lines (#6 to #8) to no avail. Finally I measured the inlet area of my cowl vs the exit area (with vetterman 4-pipe) and found I needed to get more air out. I sliced 3 inches off the lower cowl lip and lowered the oil to 195 and cyllinders to 325 in cruise. I also moved my oil cooler forward. This combination proved worthy for over 1400 hours. I have flown alot of RV4's and found that 325-350 CHT in 2450 RPM cruise is average with 180-195 oil temps in 75F OAT.
In contrast my buddy Slim put an IO-360 in his RV4 with 10.4:1 Lycon flowed cyllinders. With a Van's stock cowling with slightly more exit area than inlet and Vetterman 2 pipe it ran very cool from the start. My Rocket (10.4:1 Lycon as well) also runs very cool even in the hot summer of FL with my cowling mod on the HR2 cowl lower lip. I like to "putt" around my strip in the evening at 20 squared in my HR2 (7 gph at 150 knots)which yields 165 oil and 285 CHT's. 24 squared on the mighty IO-540 yields 195 knots at 12 GPH 330-340F CHT's. Firewall it to 27 squared down low and achieve 205 knots in level flight at 17 GPH 345-355 CHT.Woo Hoo! The cool part is landing 2 minutes later on a 1800' grass strip with the same airplane. What a great machine!

Might be worth taking a measurement on your cowl intake/exit if heat is an issue...

Your mileage may vary...

Rob Ray
 
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RV-4's are cool

goosepool said:
I have just got my new 4 airborne after 9 years of building (flatpack no P/P skins version).

I have fitted a new Superior XP-IO 360 and because the 4 is tightly cowl'd I was wondering about EGT, Oil and cylinder head temps. What sort of temp ranges should I expect to see in the 4.

Obviously with only 5 hours on a new engine she will be a little tight to start with so I need to watch the temps evan more closely. Has anyone crunched the numbers? Happy landings Stan
Click to expand...
Stan the RV-4 is one of the coolest running RV's. After break-in, assuming nominal ambient temp, you RV CHT's whould be in the mid/high 300's and OT may be down in the 190F or less. In fact many RV-4's have issues getting OT high enough. Why no one knows but it does run cool.

As far as a new engine being tight, yes it will run hotter but not for the reason you think. Most of the HOT temps, CHT and OIL on a new engine is from the fact the combustion chamber, valve face and piston top are CLEAN of all carbon deposits. Carbon acts as a thermal barrier. It takes something like 30-50 hours to get that coating. The "tightness" is not really the issue.

As far as temps during Break-ion who knows, but you want (must have it) with in limits. Although these are not red lines or limits I like to see CHT = 400F or less, OT = 210F or less. EGT is not really relevant, only relative to where you put the probes. Lyc does not issue EGT limits. However once you know what is normal EGT, clearly its a great way to analyze issues between cylinders.
 
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