What temperature do you get on your gas motor in flight? I've now got an Eagle Tree Seagull data recorder / telemetry system that measures in-flight data (altitude, engine rpm, airspeed, temperature, voltage, etc. ) I have two thermocouples - one on each cylinder of my DA 100. I'm getting 230F - 290F inside the cowl of my 35% Yak. I have the sensors mounted to the cylinder fin nearest the sparkplug - slightly to the rear of the engine. The 290 reading is after 15 seconds of full throttle climb. the ambient temperature is about 85 degrees. I have good ducting inside the cowl, but the round cowl itself blocks air from going over the hottest portion of the heads. I have three times exit area as input area.