Thanks Chris I think I get it now. So for a given RPM, that is the part I didn't catch on to, the higher pitch prop will give higher thrust, assuming the motor is already up to speed.
But considering taking off, the higher pitch prop will not generate the speed of the motor as easily and so won't develop thrust as well as a lower pitch prop.
Thanks, I just love this forum. There is so much information available it makes me like a kid again.
I really love flying or anything that flies and at the moment I am building a new solar home. It is a huge job and getting a plane in the air will be a wonderful temporary diversion from all of the work.
Here is one more question.
Is there any way to calculate the stall speed of a plane or do you just have to find out by flying?