Composite-ARF IMPACT question

Wed Mar 30 13:23:01 AKST 2005

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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>
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