Steve Sampson
Well Known Member
Not long ago I was worrying about high CHT on climb out at full power. (I can easily control this by reducing power.) Now, with about 40 hours on the engine, and unusually cool autumn weather in the UK, I am becoming much more concerned about getting the temps up in the cruise! I understand RV4 do tend to run cool, so there must be lots of ideas/experience for bringing the temps (CHT and oil) up. My oil cooler is about 80% shut off. My questions are these:
1. What is considered a realistic lower limit for the CHT in the cruise? (Steady state in the cruise the hottest #4 is at 300F, and the coolest #1 at 290F. with the oil at 140F. Letting down its easy to see these drop back to 250/260 despite trying to keep heat/power in the engine.)
2. What are the pros and cons of reducing the air going in at the front of the cowl .v. reducing the exit to increase CHT?
3. Is there any experience of just blocking one air intake behind the prop completely, with gaffer tape? Does this lead to very asymmetric cooling, or does it in fact provide a very practical low cost solution?
I have looked at the 'Alan Judy' thread - marvelous - but really don't want to redesign the front end of the cowl!
Thanks.
1. What is considered a realistic lower limit for the CHT in the cruise? (Steady state in the cruise the hottest #4 is at 300F, and the coolest #1 at 290F. with the oil at 140F. Letting down its easy to see these drop back to 250/260 despite trying to keep heat/power in the engine.)
2. What are the pros and cons of reducing the air going in at the front of the cowl .v. reducing the exit to increase CHT?
3. Is there any experience of just blocking one air intake behind the prop completely, with gaffer tape? Does this lead to very asymmetric cooling, or does it in fact provide a very practical low cost solution?
I have looked at the 'Alan Judy' thread - marvelous - but really don't want to redesign the front end of the cowl!
Thanks.