I've noticed that it seemed to run better after an oil change but always assumed it was psychological. Same thing happens when freshly washed.
I did notice that when freshly washed the airplane actually did go 5mph faster than when dirty at the same power setting. But north of 120 mph lots of dirt particles will start to produce measurable drag.
I did notice that when freshly washed the airplane actually did go 5mph faster than when dirty at the same power setting. But north of 120 mph lots of dirt particles will start to produce measurable drag.