[NSRCA-discussion] Motor Mount

[George W.Kennie]

Thanks Dave !




  ----- Original Message ----- 
  From: Dave 
  To: 'General pattern discussion' 
  Sent: Wednesday, June 03, 2009 2:04 PM
  Subject: Re: [NSRCA-discussion] Motor Mount


  George,

   

  Motors designed to be mounted on one end only in airframes with structure strong enough to handle the substantial cantilevered rotating mass work just fine.  Several years ago, several planes (different designs and manufacturers) with several motor types had problems with "whirl flutter" and motors broke loose, departed the plane, or tore the nose off the plane.  Having run softmounted, hardmounted, firewall mounted, nosering mounted, and mounted on both ends, I've found it easiest to control resonances in the plane when the mount is at both ends, and even better when a softmount is used.  A number of guys in D1 are running the Hacker A60 hardmounted to the nosering with a hardmounted aft bearing support - which the motor is designed for (Hacker sells a mount, or you can buy a flange bearing and setup your own aft support mechanism).

   

  Regards,

   

  Dave

   


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  From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of George W.Kennie
  Sent: Wednesday, June 03, 2009 12:48 PM
  To: General pattern discussion
  Subject: Re: [NSRCA-discussion] Motor Mount

   

   

  Hi John,

   

  Sorry to have to tell you that I received no replies to my inquiry.

   

  I have the feeling that most people are just not addressing this issue.

   

  It would make a great product for somebody like Jerry or Chris to produce.All that would be required is 

  an X brace with an oversize receptacle at center to receive plastic inserts (like props) sized to fit shaft

  bearings.

   

  Georgie

   

   

   

   

   

   

    ----- Original Message ----- 

    From: John Ferrell 

    To: General pattern discussion 

    Sent: Wednesday, June 03, 2009 8:50 AM

    Subject: Re: [NSRCA-discussion] Motor Mount

     

    FWIW:

    I am interested in an answer to your question too! It sure looks to me like some kind of nose bearing would be prudent...

     

    John Ferrell  W8CCW
     
    "All that is necessary for the triumph of evil is for good men to do nothing." -- Edmund Burke
    ...."The problem with socialism is that you eventually run out of other people's money."  
       MARGARET THATCHER 
    http://DixieNC.US

      ----- Original Message ----- 

      From: George W.Kennie 

      To: NSRCA Mailing List 

      Sent: Monday, June 01, 2009 4:54 PM

      Subject: [NSRCA-discussion] Motor Mount

       

      Hey Guys,

       

      I have a new project in the works and it involves mounting a 2K watt motor. This will be my first larger motor install so I felt that some advice from the Pros

      would probably be appropriate.

       

      The Motor is an outrunner and I can mount it from the back side directly to the firewall OR I can use standoffs and mount it from the front side of the motor.

      I keep feeling that there needs to be some kind of a stabilizing bearing on the free end as there portends to be a significant amount of rotating mass if I just 

      bolt the thing to the firewall while a pound of motor whirls around with a large prop exerting inertial rotating energy beyond the front of the cowl. It seems like 

      If I use the stand-offs, there will be a more rigid area between the prop and the motor, but then I worry about the back end. Should I figure out some kind of a 

      bearing mount on the firewall?

       

      Somebody set me straight on the accepted procedure please. 

       

      Thanks for you help,

       

      Georgie 

       


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