currently flying a stretched E5 with 605 mains and 105 tailblades (I run a bit lower headspeeds, so wanted more tail). Although higher cellcounts are of course better (can gear and motor for lower currents with the higher voltage for efficiency), mine's flying on 6S/5500 packs and has more than enough performance with headspeeds of 1500/1700/1900.I do however use a lot of pitch for the lower revs (16/16 collective). I use telemetry for mah consumption to land at 4500 used, and a timer at 7 minutes. The timer always goes off before the telemetry says I'm done. Average 8 to 9 minutes. I even fly it on 5S/5500 sometimes, at 1500 and 1600, and love that configuration. If you go moderate to low rpms, of course the speedup in the tail is needed, but you can get more with a simple mod. I use the 20 tooth gear on the rear end of the torque tube (from E7) which results in 5.45 to one on the tail. No this is NOT a mod that's "approved" by Matt, but it's been working in my two stretched E5's for a long time with no issues. You have to turn off the raised portion just below the actual bevel gear so it will fit, then space out the left plate on the gearbox a couple mm, and add the same amount of shims to the spacer tube on the output shaft, but it's worth the effort. If you're going to run higher revs than I do, I wouldn't do it. 2K and above, the 4.9 ratio is fine. Oh, I also use the tail output shaft from the 766. It's 3.7mm longer (If I remember correctly), so it gives you back the pitch slider movement you lose when spacing out the gear box plates that 2mm to accomodate the higher ratio.
