lml@lancaironline.net Mailing List Archive

It is true that running LOP will cause the engine to run cooler. As you all know the Legacy doesn't have cowl flaps. I built my Legacy with inlets in the cowl that are 1/4 inch smaller in diameter to reduce cooling drag, tightened up the baffling to make use of all the cooling air and I find that running LOP at altitude my CHT's will run from 278 to 300 degrees. Since I could not find anything published regarding how cool you can run the engine, I asked a tech rep. from Continental how cool you can run the IO-550 engine and what damage would result should I do so. He indicated that that's the reason you don't find a published number. Is that possible?

At the temps mentioned above, my oil temp is 180 degrees.

So, I would like to hear from you regarding your thoughts on this subject. Thanks for your input.

Art Jensen

From: Walter Atkinson <walter@advancedpilot.com>;
To: <lml@lancaironline.net>;
Subject: [LML] Re: How do I run lean of peak?
Sent: Mon, Aug 22, 2011 5:28:42 PM

But what is your actual hourly saving and is it worth the additional stress on your engines for the potentially much lower TBO? You decide and your mileage may vary.

400 million hours of flight data supports the fact that when run ROP, the TC-18 radial on the DC-7s had a TBO of 600 hours. When run LOP it had a TBO of 3600 hours. Yep, 3 thousand 6 hundred vs. 6 hundred hours.