Re: [PSUBS-MAILIST] Kittredge Motor Housing help

["Daniel D. Lance" <lanceind@gmail.com>]

Jon, yes that is the modification I was thinking about. Harold added it because he had one open up. Hard to believe but if you are really bearing down on the motors it can happen. The propellors are not ideally matched to the motors and tend to cavitate.
Dan

On 10/29/2011 11:48 AM, Jon Wallace wrote:

Dan, I'm surprised to hear this since those end caps definitely fit snug when tightened up.  The motor bearings are absorbing all the pressure from the seawater so there shouldn't be enough pressure on the mechanical seal to unwind the end cap.  Harold Maynard's modification (see link) http://www.psubs.org/convention/2003/pics.cgi?pics/k350-2/PDR_0073.JPG is better from a number of perspectives however even though it's not as hydrodynamic.

Jon

On 10/29/2011 10:19 AM, Daniel D. Lance wrote:

Alan,
Good point about the thrust bearing issue . I forgot about that. The Kittredge design has its own issue with reverse. If you try to run one in reverse the end cap holding the motor , seal and propeller assembly will unthread from the main housing. This is why if you want reverse on a K-Boat you rotate the side thrusters. Of course some modifications can be made to prevent the housings from coming apart once the o-ring is seated but you still get the occasional leak.
  I brought the minn kotas into the discussion because of how well they worked on Jim K's Bionic Guppy.   Maybe its time for a discussion for an open source thruster design.  The Kittredge thruster pod is a T-Rex waiting for an asteroid.
Dan