Stef wrote: >The temp in the cowlings is a bit > high, so I will modify the intake for the oil cooler a bit.
The first engine runs on N56ML's Corvair were done in my driveway, I ran it at full throttle for about five minutes, to prove that the engine would last long enough to get at least get to pattern altitude and back around again for landing. In that brief period of time, I overheated the engine to the point that it softened the aluminum head, allowing the collapse of a head gasket, resulting in a complete loss of compression on one cylinder. This required replacement of the entire cylinder head. Clearly, the engine can't get enough air at sustained full throttle on the ground to cool it. Once airborne, the engine cooled quite well, far better than a VW, with CHTs that rarely exceed 370F, even in a sustained climb to 10,000' on the hottest of days. 300-320F is a more usual cruise temperature for the Corvair during the summer months. The moral of the story is that cooling is far better with 160 mph air forced down the inlets, than it is sitting on the ground. My point is don't go too crazy trying to improve cooling based on ground run temperatures, or you'll be giving away a lot of speed and efficiency (due to drag) in an effort to keep your engine cool while on the ground. One data point I eventually learned is that auto fuel will vapor lock while refueling on a hot summer day, due to high under cowl temperatures while the engine is off. Idling doesn't help a lot, but revving the engine up to about 1300 RPM will gradually drop the under-cowl temps and eliminate the vapor lock. I learned this from the carb temp throat temp sensor and the under-cowl temp sensor, while at various RPMs during the summertime. Much higher throttle settings will increase the under-cowl temperatures instead. This varies with different airplanes due to cowling an baffling design, but that's the way mine works. Mark Langford, Harvest, AL ML "at" N56ML.com www.N56ML.com _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/[email protected]/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to [email protected]
