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Well, Hartmut, you certainly aren't the first person to tell me that I don't make sense...VBG. In the early 50's in Korea, I was partnered up with a guy from Austria. He frequently made the same observation. He also noted that I had very little discipline. However, in this instance, I speak from experience. I almost ruined the back jugs in my Yankee and Cheeta back in the early eighties. My job kept my away from home weeks at a time, and when I came home, I would spend a lot of time just flying around California. There was a gasoline crisis at the time, so as I was only flying for pastime, I would save fuel by flying at reduced RPM (prolonged slow flight). As I later learned, this was false economy, considering the cost of the repairs. In our typical light aircraft, we do not have controllable cowl flaps. The cowl and internal baffles are designed to keep each cylinder at operating temperature during cruise, or at nearly level flight. Normal climbout isn't that long, and we are taught to run at full power, full rich mixture, which is (usually) sufficient to keep the engine from overheating. Conversely, in a power off descent, our engines can get very cold. The two main factors that cause overheating of the rear jugs during prolonged slow flight are the reduced airflow caused by the low airspeed, the high angle at which the air is striking the intakes and the resulting reduced airflow to the rear cylinders. The baffles require a certain air pressure to allow sufficient air to flow over the rear jugs for cooling. Cheers, all...... Gordon Tanner [EMAIL PROTECTED] ----- Original Message ----- From: "Hartmut" <[EMAIL PROTECTED]> Cc: <[email protected]> Sent: Wednesday, December 04, 2002 3:41 PM Subject: Re: [COUPERS-FLYIN] Slowest Cruise Speeds > ----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]---- > > > That does not make sense. > When flying slow , the engine does not generate much heat, the cowl flaps on a Coupe are wide open all > the time and I doubt a extreme nose high attitude is given at speeds at around 85 MPH.... > I find my Coupe extreme nose high with 45 MPH, but would not consider this a practical low speed flying > technique. > All other Speeds should allow for sufficient cooling in regard to the power setting. > > Hartmut > > Gordon Tanner wrote: > > > ----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]---- > > > > One aspect of prolonged slow flight is insufficient engine cooling due to > > the extreme nose high attitude. Aircraft with cowling flaps are generally > > OK if the cowl flaps are open during this type of operation. Without extra > > cooling capacity, the back cylinders will slowly cook. It can result in > > excess carbon in the cylinders, due to the lack of cooling & slow RPM. One > > of the first indications is excess "varnish" on the inside of the valve > > covers. > > > > If you would like to join your friends, I have a nice Challenger II here in > > northern California.....that is for sale, or trade for a coupe. > > > > Gordon Tanner [EMAIL PROTECTED] > > > > ========================================================================== == == > > To leave this forum go to: http://ercoupers.com/lists.htm > > ========================================================================== == == > To leave this forum go to: http://ercoupers.com/lists.htm > > > > ========================================================================== ==== To leave this forum go to: http://ercoupers.com/lists.htm
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