Kevin, you make a couple of points that I never thought about.
1. wing loading. Heavy makes crap flight
2. Prop selection. I have been running a 10 x 6 master airscrew. I am just beginning to learn about the difference that the selection makes. I have been flying for 12 years but never as part of a club till now and am learning lots that I have been missing out on. This site and especially the users, are quite valuable to me.

The royal 40 pulls very hard. I don't think that it is worn out: but rather that I have not been treating it to the right prop. I will have to try different combo's and see what difference it makes.Yes this is verry helpful!! Thanks