[PSUBS-MAILIST] MK 2 Brushless Thruster

Thu Mar 24 17:55:04 EDT 2016

Alan,You will be glad you bolted it together, it will be a lot easier to machine .    I am only in Holland for a few days then strait to Slovakia.   Hank 

    On Thursday, March 24, 2016 3:13 PM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 OK Hank I will bolt the front section on.I had problems machining the bearing seat on the first thruster as the front section was one piece & I needed a long boring tool. I will have the same trouble if I have to machine these after welding. I will probablyloc-tite everything in on the front section as it doesn't need to come apart.The whole thruster housing (2000W) is only 80mm x 174mm (3&1/4" X 7")& there is very little to it.Are you planning any other submarine events in Europe apart from visiting Emile?I went up to Cherbourg & had a look at the submarine museum. You could spenda day there, I am sure your wife would love it.Cheers Alan

      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Friday, March 25, 2016 9:05 AM
 Subject: Re: [PSUBS-MAILIST] MK 2 Brushless Thruster

Alan,I like the two seals also and now that you mention you are putting in a fill plug to vent air-I am with you.  I would get it welded before you machine the bearing seats etc, if possible.I would still make both ends bolt together-there is nothing like having it come apart to work on it.  My Perry thrusters break down into a million pieces and it is real nice to work on.Hank 

    On Thursday, March 24, 2016 1:55 PM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Hank,I left out some details on that drawing. The back end fits the sameas the front & has a radial o-ring seal on the end housing & 6 cap screws thatbolt in to the central housing. Alan

      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Friday, March 25, 2016 1:31 AM
 Subject: Re: [PSUBS-MAILIST] MK 2 Brushless Thruster

Hi Alan,It wouldn't hurt to clamp the end cap tight but you do have a nice shoulder for the end cap to sit on.  Any time I make a part that can and usually does warp, I make it oversize and machine it true after welding.  I am curious why you want to weld it-that big shoulder has room for an o-ring.   I would also ditch the second seal-it is an air trap.    Great project!Hank 

    On Thursday, March 24, 2016 12:27 AM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

  This is my latest brushless thruster design for scrutiny.The last thruster I made was 2 piece with one seal.I machined the last version out of aluminum rod, which was expensive & difficult.The end pieces in this design are from solid rod but the mid section is from a stock tubethat I intend to have welded to the propeller end. The back end is bolted on.Am I likely to get distortion when welding the two sections together? There is a sleevepress fitting to help give it some rigidity for welding. Should I make a jig to clamp it infor welding?The thruster is for 500ft depth & is oil filled with a slight over pressure above ambient. Oil filled mainly for cooling purposes, but also as a secondary defense against any leaks,& for lubrication of bearings & seals. I am using low pressure lip seals & have a double seal redundant arrangement. The outboard seal is orientated to keep the oil in & with theinternal overpressure should keep the water out. The outboard seal should fail first as it is exposed to abrasives, especially in sea water. The inboard seal is oriented so that it keepsany water out that may get past the outboard seal. The tube coming out of the seal cavity is for pressurizing it & for collecting any water thatmay get through & come out of suspension. I am thinking of putting a water sensor in there.Any comments welcome.Alanp.s. if image isn't big enough keep hitting ctrl & + TO ENLARGE.

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