Hi Dennis,
I'm very interested. I have an SV-11 with an E-Flight 25. It weighs just over 68 ounces ready to fly, (is very draggy as we all know )and uses a 4S 3900 TP pack with a Hubin FM-9 and Phoenix 45. The first 10-12 outings were flown using the APC 13x 4.5 EP. The motor bit the dust( bearings, armature scuff) due to oscillation and resulting heat. The plane flew a 5.4 lap on .018 x 63' ( eyelet to eyelet) @ approx. 9,450 RPM. The replacement E-25 has been incremently ( read slowly) advanced along ( Governor Gain & PWM rate reduced). However, I then had to increase the RPM to nearly 9,900 RPM to a achieve 5.8 lap which was too slow for this ship and me. Yesterday, I tried a 12x6 EP " old style" and was able to get 5.3 at just over 8,200 RPM, so I feel I'm getting closer to my target 5.4-5.5 lap time with the all important side benefit of reduced RPM and heat.
Okay, I think a 12x7EP would be about right- I could lower the RPM more , get a lap time to my liking, and perhaps get more punch for the verticals and overheads.
For me, it would need to have a hub no thicker than the "old style"12x6 EP because there isn't much thread left on the shaft for the nut with a GP E- plastic Spinner.
Do you think a 13X 4.5 cut to 12 or 12 1/2 might work. I'm afraid that the new 13x 5.5 might be a bit much; even if cut.