Originally Posted by
1967brutus
Define "touchable"... if they really are touchable, that is rather "cold" to my taste. I prefer my gasoline engines to run between 80 and 120 degrees C. Below that is too cold for my taste.
If I can permanently touch something, it is 55 deg or colder. Don't overcool your engines, lubrication is less good when too cold.
By the way: Nice video, great sound!
An example of a graph with temperature and RPM
Temperature of cylinder 1 (hottest) measured during a cool flight on a modified engine. The sensor is glued to the fin under the exhaust outlet. The difference between the hottest and the coolest cylinder is less than 10 deg C. Air temp 10deg C
On an engine out of the box, the temperature can exceed 150deg C on cylinder 1 and the difference between the hottest and the coolest can exceed 40 deg.
JM