Conference vmszoo::rc

    
    Dan, A couple of degrees of positive shouldn't hurt you. 
    
    One thing to do is to allow for plenty of air flow over the
    batteries.  From what little I've read or seen this is one of your
    major problems that you face.
    
    					Tom

    Dan,
    
    There are a few mentions of incidence in topic 246 but I think what
    yer' lookin' fer' is discussed in the pattern topic, specifically
    notes 279.25-thru-.31. We probably should've created a topic specific
    to incidence/trimming...oh well.
    
    Adios,	Al

    Would an expert (Tom or AL?) please author a trimming topic?
    
    Also, if a plane has positive (or Negative) incidence in the wing,
    would this not affect the trim of the plane greatly while inverted?
    
    Chris

    Chris,
    
    Re: .-1..., Yes, positive incidence will have an effect on the plane
    in inverted flight but the effect is not detrimental.  A degree
    or two of positive incidence merely means a small amount of down-
    elevator must be held to keep the nose up and the angle of attack
    in such an attitude that level flight can be maintained.  My MiG-3
    is set up 0-0-0 and requires only the slightest "breath" of down
    to keep it level in inverted flight, probably necessitated by the
    semi [rather than full] symmetrical airfoil of the wing.
    
    As a general rule, you'll find that almost "any" ship will require
    "some" geater or lesser amount of down-elevator to maintain level,
    inverted flight so the incidence thing is really a minor consider-
    ation as it only changes slightly the amount of down required. 
    
    As to negative incidence..., I don't know why anyone'd want negative
    in a monoplane but the effect would be to diminish the amount of
    down required in inverted attitudes...just the opposite of positive
    incidence.
    
    Adios,	Al 

    Al,
    
    I had a feelin' it was something like that.  My PT40 requires lots
    of down to fly inverted.  Yes, I know it is because of the flat
    bottom wing.  The Skooter II that I flew only needed a "breath"
    to maitain level flight.
    
    Please excuse my ignorance when it comes to negative incidence,
    I realize now the effect it would have on a monoplane.  Do Bi/Tri
    planes use negative?  If so, WHY?
    
    

    Chris, Al and I have had a constant agreed upon disagreement on
    this one but our common ground is that difference in wing  incedencs
    in multiwinged planes is done to effect the planes stall
    charactoristics.
    
    
    
    						Tom

    I see, you agree on disagreeing.  Shoot, I better stay outa' this'n!
    
    Then two negatives equal a positive, so... when the wing and stab
    are both negative the effect is positive! ;-}
    
    Hah,
    
    Chris
    

    For those of you who don't have a incedence meter you can and should
    still check the incedence of your wings. Here is a method how.
    
    Start by tracing the airfoil of your wing on a piece of tracing
    paper. This the the airfoil including sheeting. Not just the rib.
    
    Now cut a rectangle out of card stock larger than the tracing.Make
    sure that all sides are as parallel and perpendicular as possible.In
    the center of this card (long ways) draw a line parallel to the
    bottom edge of the card. Now transfer the tracing of the wings airfoil
    onto the card. Cut out this airfoil and make sure that it will fit
    over the wing yet still be snug.
    
    Place the plane on a flat surface and level the thrust line. Install
    the card on the wingtip and measure from the surface to the rear
    bottom corner of the card. Repeat this measuring but to the front
    bottom corner. Subtract the lesser measurement from the larged.
    You now know the length of one side of a triangle produced by the
    angle of incedence in the wing to the thrust line. Use trig. to
    determine the small angle of the triangle. If you can't see this
    in your mind draw it out and it will make sence.
    
    
    						Tom

A couple of weeks ago my venerable Eaglet suffered some damage to
its tail feathers that dictated I rip the whole mess off and
start over.  This I did, taking the stabilizer off right down to
its platform on the fuse.  I built and covered new tailfeathers
in a (for me) record time of 3 evenings.

So last Saturday I went to the field and got an instructor to
take it up for its trim flight.  The first thing he spotted was
that I had an excessive gap at the stab hinge of about 3/16-inch.
He said that he didn't think it would fly.  Sure enough, it
wouldn't get off the ground.  So he told me to fix the gap and
come back again.

OK.  So I go back to my field box and decide that since I can't
fly the plane,  I might as well run the fuel out to see if I've
solved the tank problem (I haven't been able to get a consistent
full tank run out of the plane because of the tank position). 

Alright, now with all the preamble, we start on the meat of this
tale.  As I was carrying it over to the run-up pad one of the
more respected pilots in the club came over and asked me to hold
the plane level.  He pointed out that the wing is set at a
negative incidence, and this was probably why it wouldn't fly. 

Since I 1) don't own an incidence meter, and 2) am skeptical of
advice at the field anyway, I went by my model junkie Phlyin Phil's
shop on the way home and asked him to check it.  Yup, it was a
whopping 3 1/2 degrees negative!  But Phil said to not worry,
because it was probably built in that way.  He said that Goldberg
did this sometimes on his flat bottom wing ships to minimize
floating.

Then Phil said something that made my ears perk up: he said that
a side effect of negative incidence is that the plane will tend
to drop its nose severely in a turn.  Boy, if that isn't the
truth with this bird!  He also showed me how to wedge the wing up
to reduce the incidence, and we found that it would take a 1/2
inch wedge under the wing leading edge to bring the wing back to
0 degrees.

So just to verify that the Old Master (Goldberg, not Phil) knew
what he was doing, I measured the incidence off the plan and it
came out to around 4 degrees.

Now, to the point of this:

1) If you've got an Eaglet, assuming you can keep the engine
running, have you noticed an unusual tendency for it to drop its
nose in a turn?  I'm running 3 channels, and to turn the plane I
give it about halfway over on the rudder to get the yaw-induced
roll, then pull the elevator back sharply and neutralize the
rudder.  The plane will continue turning with zero rudder and
heavy back stick on the elevator. Lighten up a bit on the
elevator, or hold that rudder over too long, and down, that's
DOWN, she goes!   I go to this elaborate detail because, if
you're a student, your instructor is probably yelling at you
about overcontrolling, when its both an incorrect sequence of
commands to the plane, and undercontrol of the elevator that's
the problem.  Think yaw-induced roll; that's the key.  But I'm
getting off into my instructor diatribe again... 

2) What's the consequences of reducing the incidence to let's say
2 degrees, or even zero?  I can do this with wedges under the
wing leading edge.  

3)  Because I've been practicing approaches lately, I've dinged
the nose gear back a few times.  I've had to remove the gear to
straighten the wire.  In resetting the gear, I've carelessly put
it in all the way to the spring.  While measuring the incidence I
noticed the little note on the plan that said if you fly off a
grass field, to set the spring about 1/2 inch off the mount.
Well, I don't fly off grass, but I do fly at 7200 feet, and
that's just as bad.  I've noticed that it takes an abnormal
amount of roll to lift off, and figured its the altitude; now I
think its been my habit of setting the spring in.  I've reset it
now, and will try that theory out this weekend.

    John,
    
    I was teaching a guy on an Eaglet a coupla' years back and I also
    noticed its propensity for dropping the nose and "tucking-in," that
    is, increasing the angle of bank and tightening up, in a turn.  Damned
    uncomfortable, I thought, and not a great characteristic for a supposed
    trainer.  Of course, you and everyone else knows my opinion of
    flat-bottom winged trainers, but that's another story.  Point is, 
    this student became so discouraged that he quit from not being able 
    to predict/control the airplane in the turns.  He was a little low
    on the "aptitude-scale" anyway but the Eaglet completely unnerved
    him and, finally, caused him to throw in the towel.  Aptitude notwith-
    standing, I believe he _could_ have learned on a better airplane.
    
    As to changing wing-incidence, I can predict that you may correct
    the nose-dropping and tucking in the turns but the price (with a
    flat-bottomed wing) may be ballooning out of the turns and increased
    elevator sensitivity, not a desireable trait for a trainer.  My
    suggestion would be to experiment with it, shimming the wing
    leading-edge a little at a time until no further improvement is
    realized or undesired behavior is  exhibited.  Question: Where is
    the stab/elevator incidence in relationship with the wing (decolage)?
    This will definitey have an impact on how changing wing-incidence
    affects flight.                                                  
    
    Yer' supposition on length of the nosewheel strut is basically correct.
    Ideally, the nosewheel length on most ships should be such as to place 
    the angle of attack of the wing (with respect to the ground) at zero-
    degrees.  For a trainer, just a tad negative, say -1 degree, might
    help the plane "stick" on landings but this increases the length
    of the takeoff run as the airspeed over the elevator must achieve
    adequate power to overcome the airflow holding the wing in the
    negative angle-of-attack dictated by the nose-strut length.  The
    usual result is that the airplane suddenly _leaps_ into the air,
    rather steeply at times, causing a situation that must be reacted
    to quickly to prevent stalling.
    
    BTW, the incidence discussion(s) are in a topic called "Get It In
    Trim" or something close to that.  Do a DIR/TITLE="topic_title"
    to find it...wildcards will help when unsure of the exact title.
    
     

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

Al, thanks for the reply; I knew you'd come through on this one.
You just saved me a ton of fretting by relating your experience
with the student; that guy coulda been me for the way you
described him. 

I've blamed myself for the plane tucking, and as I've said
elsewhere,  the instructors haven't been much help either.
Yes, its uncomfortable, and unnerving to say the least.  I credit
a fanatical learn-to-fly attitude to keeping me going--and I'll
also admit that there were a couple of times when I'd just as
soon stomped the whole thing to sticks! 

One thing I had in mind by posting this was that there are
probably other students out there who are having just as hard a
time with the Eaglet and don't know why.  Just knowing that the
bird is quirky has helped me 100%. 

For the record, I do not recommend the Eaglet as a trainer.  It
is difficult to fly, and the instructors, who fly aileron and .40
sized ships 99% of the time do not understand the plane.  They
will blame the Eaglet's small size and the student's inaptitude
for something that seems now to be due to the plane's
characteristics.  I do however, recommend the Eagle; I've seen it
flown and soloed many times in my year and some month's quest for
Learning To Fly, and it is very good indeed.  The hitch is in
expecting the same of the Eaglet -- they only look alike!

Ok so on to incidence.  You asked me what the stab/elev was with
relation to the incidence.  I thought that the difference between
the stab/elev and the wing was the definition of incidence.
Anyway, the 3 1/2 degrees negative that I measured was between
the wing and stab/elev. The engine is given a slight down and
side thrust, but with a little imagination you could say that the
stab/elev is on the thrust line. 

Let's say that I put a shim under the wing after the plane has a
trim flight -- will that change the trim substantially?  The
reason I ask is that I'm still pretty marginal in terms of
keeping the plane in the air, and I don't want any more
surprises.  If it changes the trim I'll have an instructor test
fly it again.  Phil said that a good rule of thumb is to figure
about 1 degree of incidence change with each 1/8-inch shim, and
on the Eaglet that is about right.  A 1/8 inch shim puts the
incidence meter at about 2 1/2 degrees negative. 

Your comment about increased elevator sensitivity kind of bothers
me -- but on the other hand, it does seem to need a lot of back
stick to hold it level now; something between 1/2 and 3/4 of the
stick's travel.  So maybe a little more sensitivity will be ok.
In any event, I think that I have enough experience to handle it
after a few minutes flying.

Does "ballooning in the turns" mean that it kind of tracks
unsteady as it goes around?  I've noticed that it is very
difficult to get the upwind and downwind turns alike -- beyond
what I've learned to expect due to the wind (oh have I opened a
can of worms here?).  Also, it drops its nose when you pull the
power back for an approach; this is what it did when I munched
the tail feathers a couple of weeks ago.  Maybe a little floating
would be good? 

Yes, I've noticed that the plane will roll for about 200' before
popping up, and I've figured that was due to the altitude and my
overcontrol.  Most instructors have been able to lift it fairly
smoothly after an equivalent roll.  We'll see where that
adjustment gets me this weekend.  I've seen the plane jump up in
less than 50 feet and questioned why, but never pursued it
further.   The thing that's saved my butt is that the OS .25 in
the nose will pull that thing up at a very steep angle.

John,

>Al, thanks for the reply; I knew you'd come through on this one.
>You just saved me a ton of fretting by relating your experience
>with the student; that guy coulda been me for the way you
>described him. 

*  Exactly what I was thinking.

>For the record, I do not recommend the Eaglet as a trainer. 

*  Neither do I...or any other flat-bottom winged bird!!  But, as I said, that's
another subject and I'm sure there are those who disagree with me on that point
for their own valid reasons.

>Ok so on to incidence.  You asked me what the stab/elev was with
>relation to the incidence.  I thought that the difference between
>the stab/elev and the wing was the definition of incidence.
>Anyway, the 3 1/2 degrees negative that I measured was between
>the wing and stab/elev. The engine is given a slight down and

*  Nope!  Both the wing _and_ the stab, even the engine has incidence, defined
as the angular difference measured from the fuselage centerline.  The angular 
difference measured between the wing-and-stab is called "decolage."  Based on
what you describe, your airplane does _not_ have 3 1/2-degrees of incidence; it 
has 3 1/2-degrees of _decolage_ and the difference in terms is significant.  For
example, if the wing has 3 1/2-degrees positive incidence with respect to the 
fuselage centerline, and the stab is set at zero, then the decolage is 3 1/2-
degrees also.  However, in the same example, if the stab is _also_ set at 3 1/2-
degrees positive incidence, then the decolage equals "zero."   Sticking with
the same scenario, if the stab were set at 3 1/2-degrees _negative_ incidence
relative to the fuse-centerline, then the decolage would equal _7-degrees_.  
The key question at this point is; what is the wing incidence?

>Let's say that I put a shim under the wing after the plane has a
>trim flight -- will that change the trim substantially?  

*  Quite possibly.  making the wing more positive will increase lift requiring
either down-elevator trim or less up-trim.

>.........................A 1/8 inch shim puts the
>incidence meter at about 2 1/2 degrees negative. 

* Relative to the fuse-centerline?  This sounds like incidence to me where your
earlier comment said the 3 1/2-degrees was measured between the wing and _stab_.
I'm confused, John...which is it??

>Your comment about increased elevator sensitivity kind of bothers
>me -- but on the other hand, it does seem to need a lot of back
>stick to hold it level now; something between 1/2 and 3/4 of the
>stick's travel.  So maybe a little more sensitivity will be ok.

*  I agree.

>Does "ballooning in the turns" mean that it kind of tracks
>unsteady as it goes around?  

*  No!  Ballooning means that when you roll out of a turn and release yer' back-
pressure (up-elevator), the aircraft balloons (climbs), perhaps requiring a 
touch of down to resume level flight.  This is _not_ a desireable behavior for 
student to have to cope with with a trainer.  Reduction of power may cause a 
similar effect on landing approaches.

>.................................I've noticed that it is very
>difficult to get the upwind and downwind turns alike....

*  This is a function [mainly] of pilotage and it gives enev the pros fits.
That's why the horizontal figure-8 is a mandatory maneuver in the flight pat-
tern for scale...it challenges the pilot to compensate/adjust for various wind 
conditions throughout the maneuver in an attempt to make both 360-degree turns 
appear the same.  This maneuver is almost universally considered as _the_ most
difficult one in the scale pattern.

>Yes, I've noticed that the plane will roll for about 200' before
>popping up, and I've figured that was due to the altitude and my
>overcontrol.....The thing that's saved my butt is that the OS .25 in
>the nose will pull that thing up at a very steep angle.

*  This is definitely a function of the plane (wing) sitting too negative rela-
tive to the ground.  Lengthening the nosewheel strut will dramatically improve 
this characteristic.  Don't depend on that engine saving the bacon; one day 
it'll quit immediately after one of those leapin'-lizards takeoffs and you'll
lose the whole enchilada!!!  Properly set up the ground stance/attitude and 
practice gentle rotations and shallow climb-outs after takeoff.  Not only is 
this a heck of a lot more realistic and pleasing to the eye, it's one _helluva_
lot safer, should the engine falter or quit.
    
      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

Well, in much the same way as has been described in other notes,
we blocked up the fuse until a level placed on the stab showed 0.
Then we put the incidence meter on the wing and got -3 1/2
degrees.

Thanks for clearing up my confusion about the definition of
incidence.  Figured that if it was measured with an incidence
meter, it must be incidence! :-)  I'll check it again tonite, but
I believe that the Eaglet's stabilizer is parallel with a line
drawn down the center of the fuse.

    John,
    
    Ok, what you describe does, indeed, sound as if the stab is set
    to zero respective of the fuse centerline.  This being the case,
    yer' dealing with the wing being 3 1/2-degrees negative to the fuse-
    centerline which validates all the suppositions I made earlier.
    This seems a peculiar force-arrangement to me, even considering a
    flat-bottom wing.
    
    I know, I had a coupla' occasions with my student's Eaglet where,
    as I rolled out of my turn onto final approach, the nose pitched
    down severely enough to make me think I may've experienced a radio
    "hit."  This guy's radio was an archaic Futaba which didn't exhibit
    the best of care and maintenance, so I sluffed it off to radio and
    never thought about it much more.  With this negative-incidence
    revelation, however, I can readily see it was the airplane's
    force-arrangement causing the [apparent] glitches, not the radio.  
    Beats me how they can pass this plane off as a trainer with such
    built-in eccentricities as these.       
    
    Experiment with reducing the wing's negative incidence and you just
    might get a better flying ship as a result.  (It wouldn't be the
    first time the so-called experts were proven wrong.)

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

Glad to see that note; the next time my heart goes to my throat
as I pull power on downwind and the nose heads for the ground,
I'll feel better.  Actually, I expect it now; wonder what it'll
be like to fly a real model!

I did measure the plan last night, and found that it is the wing
that is set to the fuse center line; the stab is at 3 1/2 degrees
positive.  Does this foul up the arithmetic?  Also, I checked
with Goldberg's 1982 article in RCM on the Eagle and found that
the drawings show a similar arrangement.  I noticed that while
the Eagle construction article was in the magazine, and Goldberg
said that the kit would be available soon, the Eaglet was being
advertised as a new trainer.  (Also in that mag, was an
"new" advertisement for my current favorite covering material
Micafilm)

Since I know that the Eagle flies fine, maybe keeping the same
force arrangement with the Eaglet was a design mistake?  I mean,
when scaling a plan between sizes, do you normally keep the same
incidence/decalage/decolage settings?

I consulted my star charts and hexagrams, did some dowsing, and
spit to windward, and decided that a 3/32 shim under the wing
leading edge should be about right to make a noticeable change,
but not cause a serious problem.  We'll see this weekend.

    John,
    
    The arithmetic stays pretty much the same; you _still_ have 3
    1/2-degrees of "decolage" between wing and stab.  But, with the
    wing (not the stab) set to zero with the fuse-centerline, increasing
    the incidence of the wing will do all the things we want it to with
    an added bonus(s): effective engine down-thrust.  This may-or-may-not
    be a desireable by-product.  Only experimentation will tell but
    I tend to believe it will be a plus.
    
    Yes, force-arrangements can change when scaling up or down.  I don't
    pretend to know the why's of it but it has to do with Reynolds Numbers
    and other such sorcery.  Suffice to say it does happen.
    
    Good luck this weekend and let us know how things turn out.  
    
    WHOA!  HOLD IT!!  DID YOU SAY THE STAB IS SET "POSITIVE."  Are you
    sure??  The leading-edge of the stab is positive (above) the fuse
    centerline??  If this be the case, you effectively have built-in
    down-elevator trim.  Hmmmmmmmmmm, I'd guess that's to control/limit
    the ballooning out of the turns that flat-bottom wings are notorious
    for.  Lemme' thin a moment....yep! the rules should stay the same
    as described above and, if the birds tucking/dropping the nose in
    turns now, a little ballooning might be just the ticket.  BTW, in
    response to yer' musing, yer' gonna' love flying a good airplane
    once you've left this "pile-of-compromises" behind.

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

Yes, the leading edge of the stab is raised with respect to the
fuse centerline.

Now that some of the smoke is cleared, I'd like to ask an
additional question that I've been holding: You're referencing
everything to the "fuse centerline"  This seems to be a rather
arbitrary reference point, since it can only be described
mathmetically by a wavy line down the center of each point.  It
would start at the center of the nose, go up a bit at the cabin,
and then curve downward as it follows the taper to the tail.

Obviously, this is useful only in describing the forces from a
non-mathemetical viewpoint, or from the viewpoint of very complex
math!  Why is something as important and as exactly stated as
incidence referenced to such a line?

    Yes, determining the fuse-centerline can be a rather tenuous
    proposition.  I normally work from only a station or two at the
    nose and a like number at the tail to make this determination.
    The reason the centerline is used (where the thrustline would be
    much easier to determine) is that engine thrust is another variable,
    just like wing and stab incidence and it (the thrustline) too must
    be related to _something_ and that something is the fuse-centerline.
    
    As you point out, the centerline cannot be determined by plotting
    the centers at each fuse station then connecting-the-dots.  You
    correctly identify the result of this process as a very irregular,
    anything but straight line.  This is why I use only a coupla' points
    plotted at the nose and at the tail (usually the rudder-post.  The
    resulting centerline (also called fuselage datum line) is then used
    merely as a reference to tie all aspects of the force-arrangement,
    i.e. wing/stab incidence and engine thrust, to a common denominator.
    
    If we simply eyeballed a datum and the resulting angles came out
    sounding absurd, e.g. +6-degrees wing incidence, +5-degrees stab
    incidence and +4-degrees engine thrust, the resulting forrce
    arrangement would sound (and be) quite normal/acceptable: decolage
    = 1-degree with 2-degrees downthrust.  See what I'm getting at??
    The centerline (datum line) is merely a point of reference and,
    of itself, is not critical in the least.
    
    Frequently, the centerline simply describes the desired in-flight
    attitude of the aircraft, i.e. tail-high, level or tail-low.  Incidence
    and thrust angles then are simply constructed from this line to
    achieve this flight attitude.    

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

    One of the few things I learned in college:
    
    	Positive decollage is _very_ important if the ship is going
    to survive a stall!  Reason works like this:
    
    
    	Stall occurs when angle of attack is too large.
                  
    
        If wing has higher angle of attack than stabilizer, then
    	wing stalls first, stabilizer continues to "fly" and ship
    	remains controllable (though the nose falls due to stall).
    	As soon as the nose dips, airspeed increases and the wing
    	unstalls.
    
    	If stabilizer has higher angle of attack, then stabilizer 
    	stalls first, tail falls out of sky, wing continues flying,
    	ship points itself toward sky _BUT CANNOT BE CONTROLLED_ 
    	because the elevator is stalled!  Angle of attack then 
    	increases and the wing starts to stall too- but the entire
    	ship is now tumbling in it's own turbulence and completely
    	out of control.
    
    	The only way to get out of this situation is to get enough 
    	throttle/slipstream up to get the stabilizer out of stall
    	BEFORE the wing stalls.  Otherwise the controls become 
    	ineffective and an uncontrolled tumble to the surface 
    	is likely.
    
    
    Make sense?
    		-Bill
    

    Another phenomenon related to tail surface stall is called "Deep
    Stall".  It is a condition in which the tail stalls when the
    attitude of the plane is such that the tail is in the slipstream
    of the wing when the wing stalls.  When this happens, the attitude
    of the plane cannot be adjusted and it stays in the stall unless
    an act of god saves it.  Very often, this condition means the
    destruction of the aircraft.  I can't remeber the name of the
    plane, but one fairly popular passenger plane designed in the late
    50's suffered from this problem, killing quite a few test-crews,
    before the aerodynamic engineers finally figured out what the
    problem was. 

Well, I got a chance to fly my reworked Eaglet this weekend.  I
asked the chief instructor to trim it up for me, so he took it
off and trimmed it.  He commented that the rudder needed an awful
lot of left trim, more on that later, handed me the box, and
walked off!  So I got my first all-alone flight on an active club
day (previously, I flew it alone, but there was noone there).
Anyway, after shaking down a bit I landed it just fine.  There
was a small bit of micafilm lifted off the tail surfaces, so that
ended my flying for the day.

The plane did seem easier to hold level in the turns, but that
could've been my imagination.  Anyway, I'm leaving it that way,
since its more important now to get the time in.

On the rudder trim. This kind of surprised me. Its almost exactly
the left trim I had in originally with the old surfaces.  When I
recovered the wing, I checked it and it seemed straight (this was
following my first all-alone flight mentioned above).  At that
time I figured the trim came from the tail feathers, since they
were a mess.  But the new surfaces are requiring the same trim,
so I guess that wasn't the problem.  Any ideas?  The engine has a
small downthrust and some right thrust, think that might be it?

The amount of rudder trimmed in is about 1/8 inch left from dead
center.

Also, along the same lines, I asked an Eagle owner what his
settings were and he said that he measured +2 on the wing, and -1
on the stab, which is what I would've expected for a normal
plane.  Maybe Goldberg saw an error in his ways?  There are lots
of Eagles in the club, so I'll ask a few more folks.  

I kind of buried this question in the previous reply; could
someone answer:

>time I figured the trim came from the tail feathers, since they
>were a mess.  But the new surfaces are requiring the same trim,
>so I guess that wasn't the problem.  Any ideas?  The engine has a
>small downthrust and some right thrust, think that might be it?

>The amount of rudder trimmed in is about 1/8 inch left from dead
>center.

    John,
    
    It's possibile.  Do you require greater/lesser amounts or rudder-trim
    at various throttle settings?  If so, it might pay to experiment
    with the thrust-setting to square away the rudder.  If no appreciable
    trim change is noted, however, leave things be...yer' merely piddling
    with cosmetics if the latter is the case.
    
    1/8" really isn't very much and, to be honest, if it were me, I'd,
    quite frankly, leave it alone, adjust the rudder linkage such that
    flight trim is centered on the transmitter and go about the business
    of getting all the stick time I could.  Don't sweat the cosmetics.  

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)