I finally flew the Sea Fury the other day. The wind was gusting up to about 12 mph, so not ideal for a maiden flight, but I had waited too long already. She flies well, though I would prefer a little more power to turn that big prop. Here's some video of the flight.
After the flight, I decided I would try to step down the gear ratio a little to squeeze out a few more RPM's. I have two heat sinks installed on the little 20 mm Himax, so hopefully I can push it a little more. Before swapping out the gears, I decided to run it up on the watt meter to see exactly what I'm pulling with 7.33:1 gear reduction. I got it up to WOT and 22 amps, then about 2 seconds later the RPM's dropped and the gears started making a terrible grinding noise
I shut her down and took out the motor. The spur gear is shot! I have a feeling that the Himax gearbox is not quite up to the task. I was pushing 260 watts at the point that the gear failed, so my guess is that it's designed for about 200. I thought about ordering a Cobri gearbox, but it has a 4 mm shaft and my VarioProp is drilled for 3mm. Then I found the Hyperion gearboxes. It has a nice beefy spur gear, comes with either a 3mm or 4mm shaft, and is rated for 300 watts. Perfect! It's also half the price of a Cobri. Item ordered and on the way from allerc.com. I'll try it at 6.8:1 to start.