[NSRCA-discussion] Partner set-up question

Thu Oct 19 15:58:23 AKDT 2006

Claude,
I have to confess that most of my opinions are based solely on the empiricle results of building my own designs and finding out through experience what works. I'm sure you're aware that "what works" for one individual is not always going to be "what works" for someone else. To demonstrate, in my opinion, the Eclipse you had with the stab at the 3/8" lowered point was as close to neutral as is possible with the design. If you have a plane that pulls with one rudder and pushes with the other that should be equalibrium and the mixes to trim this out should be in the 2% bracket. You can't see 2% !  When you raised the stab back up, the rudder that was pushing should have seen an amplification of that problem, so I would have to conclude that your "little adjustment" altered something additional to affect the aerodynamic effects involved.
I also like to see a design that requires as close to zero mix as possible, but as you are aware there are many many variables to overcome and aesthetics can often
complicate desirable characteristics to the point of compromise. 
The numbers I quoted are nothing more than good sounding measurements based on the limited info available. It really gets a lot more detailed than can be resolved without actually seeing the airplane and doing some actual measuring, however, the dihedral thing is probably a real close guess.....and yes it's as tough to change as you think especially with plug in wings. Maybe a new set of cores with the proper tube angles would be the easiest......and yeah, I too like bantering the aerodynamic techie stuff (not that I'm all that qualified).
Regards,
Georgie

  ----- Original Message ----- 
  From: Claude Weimer 
  To: 'NSRCA Mailing List' 
  Sent: Wednesday, October 18, 2006 10:22 PM
  Subject: Re: [NSRCA-discussion] Partner set-up question

  Hey George,

  Are the dimensions you gave me what it takes to fix a Partner? Does a Partner roll in knife edge? I thought the Partners were pretty good. I can tell you I lowered the stab 3/8" on an Eclipse and it pushed to the gear with left rudder and to the canopy with right rudder. Dave Guerin just looked at the plane and said "the stab is too low" so I raised it the diameter of the stab tube (about 7/16") and with a little adjustment it fixed it. I don't have any mix in the airplane and it flies great. I am not a fan of mixing problems out if you can fix it with out mixing. Any way this experience really got me interested in these measurements. By the way how do you go about adding dihedral to plug-in wings? Is it as difficult as I think it is? Any way I find this kind of stuff more interesting than interrupting the judging criteria of a figure M.

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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, October 18, 2006 12:02 PM
  To: NSRCA Mailing List
  Subject: Re: [NSRCA-discussion] Partner set-up question

  Hey Claude,

  I don't know how extreme you want to get in fixing the flight anomolies of your Genesis, but if it is indeed exactly the same as the Partner in measurement details, then you can fix it by adding 5/32"dihedral on each panel and lowering the stab to 33mm below the datum line.

  G.

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

    From: Claude Weimer 

    To: 'NSRCA Mailing List' 

    Sent: Wednesday, October 18, 2006 12:00 AM

    Subject: Re: [NSRCA-discussion] Partner set-up question

    Thanks for the effort Tom. I will tell you what I'm doing. A guy in our group has a Genesis ARF and it does some weird things in knife edge. I think the Genesis is a Partner copy and I want to see if the setup is the same. Another one in our group is going to build a Genesis this winter and if the Partner is set up different he is going to set it up like the Partner. Roberts's plane, the guy with the Genesis ARF, will tuck to the gear and roll right with left rudder. It is not as bad with the right rudder. The guys in Chicago have Genesis and some are having problems also. So I thought it would be interesting to compare the two planes. Thanks again, Claude.

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    From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Koenig, Tom
    Sent: Tuesday, October 17, 2006 5:17 PM
    To: NSRCA Mailing List
    Subject: Re: [NSRCA-discussion] Partner set-up question

    Hello Claude and all,

    These are the measurements I came up with. Please-if anyone has other data it would be interesting to compare. First up nothing earth shattering as far as the numbers are concerned. Quite standard actually.

    Partner

    With reference to the canopy floor.

    Datum line/spinner center    56 mm below canopy line

    wing center                        92 mm below canopy line( or 36 mm below datum line)

    stab center                        63 mm below canopy line( or 7 mm below datum line)

    Lazulite

    With reference to the canopy floor.

    Datum line/spinner center    56 mm below canopy line

    wing center                        90 mm below canopy line( or 34 mm below datum line)

    stab center                       57 mm below canopy line( or 1 mm below datum line)

    I presume that with the stab center on the Lazulite, I may have made an error in measurement and that the stab is actually located ON the datum line( it was getting late!)

    The models are actually very similar, with a bit of coaxing the Lazulite Canopy will fit on a Partner and vice versa.

    I have not compared 1/4 chord to 1/4 chord moments-but if these are wanted I'll measure that up as well.

    The Lazulite was disgustingly close ( by millimeters) to my own Merlin design.I'm still kicking myself for the cash that was 'burnt'.

    Hope it is of help.

    Tom

      -----Original Message-----
      From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Claude Weimer
      Sent: Tuesday, 17 October 2006 8:52 AM
      To: 'NSRCA Mailing List'
      Subject: Re: [NSRCA-discussion] Partner set-up question

      Tom,

      No one else has responded.  I would really appreciate if you could give me the information. I can deal with metrics if that's what you use. 

      Thanks, Claude

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      From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Koenig, Tom
      Sent: Monday, October 16, 2006 4:20 PM
      To: NSRCA Mailing List
      Subject: Re: [NSRCA-discussion] Partner set-up question

      Claude,

      Have you had any answers yet?

      If not-I'll measure up my unbuilt one and see what the numbers are. I hope they will make sense with the results from others?

      Tom

      -----Original Message-----
      From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Claude Weimer
      Sent: Monday, 16 October 2006 12:53 PM
      To: nsrca-discussion at lists.nsrca.org
      Subject: [NSRCA-discussion] Partner setup question

      Can some one tell me the distance below the engine thrust line to the centerline of the wing on the Partner? And I would also like to know the distance above the wing centerline to the center of the horizontal stab. Thanks, Claude. 

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