[SPAM] RE: 3-bladed props for OS160FX

[Bob Pastorello]

It would be fun, just to see who holds the torch and who twists the prop....

Bob Pastorello
NSRCA 199  AMA 46373
rcaerobob at cox.net
www.rcaerobats.net


  ----- Original Message ----- 
  From: Dean Pappas 
  To: discussion at nsrca.org 
  Sent: Wednesday, November 17, 2004 2:23 PM
  Subject: RE: [SPAM] RE: 3-bladed props for OS160FX


  Dave and I are trying to decide if he sings and I dance, or the other way around. Either way, bring ear-plugs!
  Sounds reasonable, though.

  Dean Pappas 
  Sr. Design Engineer 
  Kodeos Communications 
  111 Corporate Blvd. 
  South Plainfield, N.J. 07080 
  (908) 222-7817 phone 
  (908) 222-2392 fax 
  d.pappas at kodeos.com 

    -----Original Message-----
    From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of randy10926 at comcast.net
    Sent: Wednesday, November 17, 2004 9:45 AM
    To: discussion at nsrca.org
    Subject: [SPAM] RE: 3-bladed props for OS160FX


    How about a demo/seminar from the Dave and Dean show at the NATS next year?

    Randy

      -------------- Original message -------------- 

      And now, the Dave and Dean show have spoken ...

      Dean Pappas 
      Sr. Design Engineer 
      Kodeos Communications 
      111 Corporate Blvd. 
      South Plainfield, N.J. 07080 
      (908) 222-7817 phone 
      (908) 222-2392 fax 
      d.pappas at kodeos.com 

        -----Original Message-----
        From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of DaveL322 at comcast.net
        Sent: Wednesday, November 17, 2004 9:22 AM
        To: discussion at nsrca.org
        Subject: RE: 3-bladed props for OS160FX


        ...and a further variable....

        It is quite difficult to measure the pitch of the prop without knowing the zero angle of attack of the airfoil used on the prop (which often changes along the span of the prop).  So the pitch reading from a pitch gauge is really just a reference.  For the most part, I've found that reducing the pitch of an APC close to the root results in a fairly equal reduction along the span of the prop (as measured on a Prather pitch gauge).

        Regards,

        Dave

          -------------- Original message -------------- 

           I guess if you want to maintain a true helical pitch, if you are reducing the pitch then you will need to add some pitch back towards the tips. Higher pitch props have more twist along the blade than lower pitch props. So if you depitch at one point towards the root, then you end up with a blade that effectively has washout. Correct? That may be good for our purpose.

          Bob.


          Dean Pappas <d.pappas at kodeos.com> wrote:
            Claudio,
            Ideally you would twist the prop at several places to acheiv helical pitch. In practice, this is entirely unnecessary. Twist once, as close to the hub as practical, and that will work just fine. I see that Dave L added more detail to the procedure.

            until later,
            Dean Pappas 
            Sr. Design Engineer 
            Kodeos Communications 
            111 Corporate Blvd. 
            South Plainfield, N.J. 07080 
            (908) 222-7817 phone 
            (908) 222-2392 fax 
            d.pappas at kodeos.com 
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