Not having much luck with my SLEC Huntsman. First time out, the prop fell off after a minute. I think I forgot to check the locknut after the bathtub test.
Second time out, with a new prop and a drop of Loctite, it was making some horrible noises. A club member suggested it might be because the front end of the propshaft tube was not supported enough.
Third time out today, with a wooden fillet epoxied in place to support the tube, it was, if anything, even noisier. Fine at low RPM, bag of nails at midrange RPM and at fast cruise speed. Nice and quiet when flat out.
When I got home I tried running it on the bench - 2 distinct RPMs where it sounded horrible, a screeching/rattling sound. I tried swapping the motor, coupling and ESC to no avail.
I removed the rudder and pulled the shaft out, gave it a wipe down, and noticed some traces of brass where the shaft runs in the front bearing. I polished the marks off, relubed, and tried again. Still very noisy, and the front end of the tube was getting warm! Obviously excessive friction on the front bearing.
I pulled the shaft out again, and checked by rolling on a flat surface (old plate glass shelf). Shaft was bowed in the middle by a couple of mm. Spent an hour trying to straighten it, gave up, and pinched the inner shaft that I was going to fit in my current build - an SLEC Huntress. This one was actually straight, and after cutting a bit off the end, the Huntsman is running much quieter.
Moral of the story - check propshafts for straightness before fitting.