[PSUBS-MAILIST] props

[Alan James via Personal_Submersibles]

I thought Gamma had an internal motor.Or is this for something else?You could run a propeller fore & aft of the motor, & the brushless motors I'm looking at have provision for that.But you would need two shaft seals & have that additional friction.It would make it more complicated bolting the motor can together.If you had the propeller that was back the front, trailing, then the flowcreated by the forward propeller might help compensate for the inefficienciesof the propeller for reversing.A lot of the thruster manufacturers ( of which there aren't many ) publicizethe forward & reverse thrust. That might be interesting reading.Alan
      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Monday, December 15, 2014 2:09 PM
 Subject: Re: [PSUBS-MAILIST] props
   

Alan,
Another idea, make a thruster with a prop at each end of the motor, what do you think?
Hank--------------------------------------------
On Sun, 12/14/14, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Subject: Re: [PSUBS-MAILIST] props
 To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
 Received: Sunday, December 14, 2014, 8:04 PM
 
 
 Alan,
 Maybe it is better to make a prop that works in
 both directions.  I can afford to loose efficiency, that is
 better than mounting two thrusters in my case.
 Hank--------------------------------------------
 On Sun, 12/14/14, Alan James via
 Personal_Submersibles <personal_submersibles at psubs.org>
 wrote:
 
  Subject: Re:
 [PSUBS-MAILIST] props
  To: "Personal
 Submersibles General Discussion" <personal_submersibles at psubs.org>
  Received: Sunday, December 14, 2014, 7:04
 PM
  
  Hi
 
 Hank,I guess
  you would be getting the same
 thrust in both directions,
  butyou would
  be doubling the pitch of the propeller by
 doubling up, &
  there maybe a lot
  of turbulance between the propellers.There
 are
  propeller calculators that take a
 number of input variables
  like hp, revs,
 boat size,intended
  speed, diameter of the
 propeller & pitch. You leave one
  input
 out & it calculatesthat for
  you. You
 could call the two propellers one (add the two
  pitches together) & see what diameter
  it calculates for you at a given pitch &
 play around
  till you get the most
 efficientdiameter /
  pitch combination; then
 use the diameter but halve the
  pitch.I
  don't think I made a lot of sense, but if
 you go down
  that path I will explain a bit
 better.However
  given that submarines
 operate better with bigger diameter,
  lower
 pitch propellersit
  probably isn't a
 good idea going to two smaller higher
 
 pitched propellers.Alan
      
     From: hank pronk via
 
 Personal_Submersibles
  <personal_submersibles at psubs.org>
  
  To:
  personal_submersibles at psubs.org
 
   Sent: Monday, December
 
 15, 2014 10:38 AM
   Subject:
  [PSUBS-MAILIST] props
    
 
  Hi All,
  If I build a
 thruster
  with an extra long shaft, then put
 two props on back to
  back, one prop
 reversed.  Will the thruster perform equally
  in both directions?
  Hank
 
 _______________________________________________
  Personal_Submersibles mailing list
  Personal_Submersibles at psubs.org
  http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
  
  
   
    
  -----Inline
 Attachment Follows-----


  
 
 _______________________________________________
  Personal_Submersibles mailing list
  Personal_Submersibles at psubs.org
  http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
  
 
 _______________________________________________
 Personal_Submersibles mailing list
 Personal_Submersibles at psubs.org
 http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles

_______________________________________________
Personal_Submersibles mailing list
Personal_Submersibles at psubs.org
http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles

  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20141215/3ceaec4f/attachment-0001.html>