Composite-ARF IMPACT question

Richard Strickland richard.s at allied-callaway.com
Wed Mar 30 13:39:41 AKST 2005


Jim,

You reminded me--you know you're doing a lot of building when you start recognizing the characteristics of each of your T pins.

Richard
  ----- Original Message ----- 
  From: Jim_Woodward at beaerospace.com 
  To: Derek Koopowitz 
  Cc: discussion at nsrca.org ; discussion-request at nsrca.org 
  Sent: Wednesday, March 30, 2005 3:52 PM
  Subject: Re: Composite-ARF IMPACT question



  Hi Guys, 

  Just been through the alignment process of the Impact.  Although many are using 'zero-engine downthrust, zero stab, 0.25 wing, I decided to jig the fuse such that the nose gave 1 degree downthrust. Then measured for a zero stab and 0.25 wing.  At the top of the rudder, just measure the width and split it with a small hole for a T-pin.  I then temporarily insert a small section of balsa for the bottom of the T pin to stick in.  I then used some extra control line wire looped around the T pin, to take measurement to the wing tips and stab tips. 

  Thanks, 
  Jim 




        Derek Koopowitz <derekkoopowitz at earthlink.net> 
        Sent by: discussion-request at nsrca.org 
        03/30/2005 04:33 PM Please respond to
              Derek Koopowitz <derekkoopowitz at earthlink.net> 


       To discussion at nsrca.org, discussion at nsrca.org  
              cc  
              Subject Re: Composite-ARF IMPACT question 

              

       



  Jim,

  Based on the discussions I've read on RCU... don't rely on the seams to provide you with a measuring point for the stab or wings.  I've read that these can be off as much as 3mm.   I would take some other measurements - perhaps from the bottom of the rudder post to the trailing edge of the wingtip, for instance.

  -----Original Message-----
  From: "J.Oddino" <joddino at socal.rr.com>
  Sent: Mar 30, 2005 1:03 PM
  To: discussion at nsrca.org
  Subject: Re: Composite-ARF IMPACT question

  Lance, I hope you are right.  I've spent days trying to determine where the
  centerline (top view) of the fuse is.  Then I read where Erik said his was
  set up per the instructions so that is what I did.  I set the wing
  perpendicular by measuring from the top center of the vertical fin to the
  wing tip trailing edges and from the fin to the corner of the ailerons.
  Then I set the stab perpendicular by measuring from the seam at the spinner
  ring to the stab tips at the trailing edge.  The distance from wing tips to
  stab tips is the same on both sides but I can measure some other stuff that
  says something is wrong. If it tracks okay I won't care because I can't see
  a problem without all my jigs and tools.
  The bottom line is if you don't like spending a lot of time to get it
  perfect buy an ARF.  Having said that, I have never checked any of my ARFs
  to see how good they are in the plan view.  If it was easy we wouldn't be
  doing it.
  Jim O
  ----- Original Message ----- 
  From: "Lance Van Nostrand" <patterndude at comcast.net>
  To: <discussion at nsrca.org>
  Sent: Monday, March 28, 2005 7:51 PM
  Subject: Re: Composite-ARF IMPACT question


  > Eric,
  > Glad the plane is a winner.  I'm curious about something.
  >
  > A while back there was a thread on this plane that discussed a bit of a
  > bannana bow in the fuse.  I assume yours has this, like the others, and it
  > is inconsquential.  right?
  >
  > My curiosity on this stems from an even earlier thread about how flat a
  > table you need to make wings and how much wing bow is too much.  >From what
  I
  > remember, the conclusion was that if you can't use your wing trailing edge
  > as a reference line for laser optics than you are doing something wrong.
  >
  > This struck me as funny since I've flown some excellent planes that had
  some
  > wing warp and am of the radical opinion that there is a true error band
  > where a little wing bow (I'm talking maybe 1/8" over 32") is unnoticeable.
  > Yes, it is measureable but if no one can tell the difference than No
  flatter
  > is not inherently better.  There's always a point on the way to perfection
  > that we consider as good enough and another point where we say that our
  > tools will not allow us to measure any smaller deviations.  They are not
  > necessarily the same point!
  >
  > I've never done an engineering study but I would love to know when the
  > wing/fuse is straight enough, so that after that point I am only pursuing
  > the perfection of the craft, or to impress my friends, or to see if I can,
  > or whatever.
  >
  > --Lance
  >
  > ----- Original Message ----- 
  > From: "Grow Pattern" <pattern4u at comcast.net>
  > To: <discussion at nsrca.org>
  > Sent: Sunday, March 27, 2005 5:46 PM
  > Subject: Composite-ARF IMPACT
  >
  >
  > > Yesterday was good enough for testing pattern planes in southern NJ.
  > >
  > > I am pleased to report that if you have not yet flown your new IMPACT
  you
  > > should be pleasantly surprised.
  > >
  > > I was delighted with mine from the moment it left the ground. It took a
  > > while to program the OS mixture carb due to the cooler temperatures and
  a
  > > new liner and piston/ring.
  > >
  > > After the first flight the only mix that I could see that will be needed
  > > will be a tiny bit of  roll correction in one direction. After a
  > > length-of-the-field knife-edge KE test you could get about 1/4 of a roll
  > > in the opposite direction to the right rudder input. There was no
  elevator
  > > trim required at all.
  > >
  > > Thanks to a first class incidence-setting job by George Asteris the
  plane
  > > flew great from the outset. Some planes just feel right as they leave
  the
  > > ground. This is one of them. Thanks to all of the throw-setting advice
  in
  > > the thread there was no real need to change anything. Spins were solid
  > > with rudder and elevator only, The 2-turn reverse was as good as the
  > > pilot's timing.
  > >
  > > Because it is an IMPACT with top ailerons it has the signature
  Pterodactyl
  > > "screech!" when you snap. You just add your own "whooping!"....
  > >
  > > Regards,
  > >
  > > Eric.
  > >
  > >
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