RE: DLE 20cc Gas
RPM's are like HP ratings, basically there for bragging rights, nothing more.
RPM's will vary with humidity, temp, altitude, fuel/oil mix ratio, and air/fuel mix.
Static thrust will give you much better info for comparisons, but it too changes once airborne.
Here's the thrust figures others have already posted for the DLE20 gas engine;
APC Sport 16x7 9000 RPM 14lbs. 7oz.
JXF Beech 16x8 8300 13lbs. 10oz.
JXF Beech 17x7 7970 13lbs. 12oz.
SY 16x8 8500 13lbs. 5oz.
SY 17x8N 8200 14lbs. 9oz.
Vess 17x6 14lb. 8oz. - Great throttle response and crappy tach showed 8549RPM
Vess 17x8 14lb. 0oz. - Great throttle response only slightly less RPM than 17x6
Vess 18x6 14lb. 3oz. - Above average throttle response, may be perfect when fully broken in
Vess 16x8 13lb. 9oz. RPM through the roof (by ear) and instant throttle response spools up like an electric motor!
Zinger 16x8 - stinks, no power, way low on thrust
APC 17x4W 3D prop - decent but the idle transition was terrible, 9700 rpm!
Xoar 16x8 - Good prop but not as much thrust on the high end as the next one...
Xoar 17x6 - Hands down the best prop so far. Great punch out of hover, great top end, improved low end but more to come on this....
MA K-series 15x8 2 blade- 13lbs 11oz @ 9750 rpm.
MA K-series 15x10 2 blade- 12lbs 13oz @ 8400 rpm.
Xoar 15x8- 13lbs 5oz @ 9000 rpm.
The MA 15x8 and Xoar 15x8 have unbelievable throttle response
MA K-series 15x6 3-blade 13.0lbs @ 9100 rpm