Density altitude flying....layman's terms.....the higher you fly the easier for the engine to reach a certain rpm becomes, the down side being lower density/thrust. Also as our chamber mixture is fixed some engines can suffer from too lean a burn leading to a flameout situation. I believe this may have been the case with some engines at the WJM in South Africa.

From a manufacturing point of view and having to cater for the engines flying at higher altitude it is probably desirable to have a chamber set up with a slightly richer burn from a reliability point of view.

The full power figure for my Falcon in the Reaper at sea level 122k/22lbs/10kg/15C is 11.8oz/min.

Hope that's all clear enough and does not sound misleading

Rob.