Conference vmszoo::rc

        Re:< Note 464.0 by TARKIN::HARTWELL "Dave Hartwell" >

                I would  not  worry about a 1/8 inch on a trainer.  For a
        pattern ship I would.  I have seen amazingly crooked aircraft fly
        just fine.  Alsom  breaking  up  and  regluing is likely to cause
        other problems, such as horizontal alignment.
        
        Anker

    I agree with Anker, completely.  Removing the stab will require
    dynamite and you'd likely cause yer'self other problems in the bargain.
    As Anker says, being off only 1/8" should cause no serious flight
    problems whatever [I frankly doubt you'd feel any problem at all]
    and this slight a misalignment [probably] can't even be seen.
    
    If you feel you just have to fix it, use Dan's approach: either
    add some stock to the lead edge of the side that's too far back or
    sand a little off the side that's too far forward, then re-square
    the trail edge perpendicular to the fuse centerline.
    
    Adios,	Al

    
    One last thought before we abandone a straight plane is to try a
    heat gun. YES in most cases heat will liquify(sp) epoxy glue.
    Careful heating of the epoxied area with a covering heat gun
    might liquify(sp) the epoxy sufficiently to allow you to get the
    stab off.
    
    
    						Tom

    I would go with the majority here and just leave it alone.  Try
    to get the fin straight if you have not attached it yet.  This has
    more impact on flight trimming than the stab being a little crooked.
    On a high wing trainer, I don't think you'll notice.  Next time,
    give yourself time to set it up and mark it before glueing.  Use
    slow epoxy to allow some time for adjustment.  Pin it and recheck
    the allignment.  I ususlly put a weight on the stab to keep it seated
    on the saddle.  I then check the height on both sides and the distance
    from the tips to the fuse centerline before the glue sets up.  I
    also found an excellent way to measure long distances without the
    usual problems of bowing or stretching.  I use 30 guage wire wrap
    wire tied to a pin on the fuse centerline near the nose.  The stuff
    is light and strong, so you can pull it tight and use it to guage
    the distance to the two stab tips.  I use this for getting the wing
    straight also.  Now I wish I could figure a way to set up large
    planes that are too big to fit on my small bench.  I don't have
    any floors in my house that I trust to be flat enough.
    
    Charlie
    

    Charlie, If you can fit the plane on the bench to support it even
    though you can get the entire plane over the bench there is a way
    of measuring the stab, and wing realative to the bench. At any local
    building contractor you should be able to purchase a water level.
    I just happen to have one and have used it a number of times on
    my house and on my planes. It's kind of a specialty item but I think
    it will come in handy. What it is is a small bucket with a long
    length of clear flexable tubing. You add colored water into the
    pail and emerse the tube into the liquid to fill the tube. Set the
    pail on the bench and with the open end of the tube you mark the
    water level and the height above water level to the stab. With this
    you can then measure the opposite end of the stab and adjust until
    both sides measure the same. 
    
    
    						Tom

    Tom,
    	I like it!!  I have seen this used for construction, but I never
    thought about measuring planes with it.  I'll make something up
    and give it a try.  This should be a way to set up large planes
    on an uneven surface. (My floors)
    
    THanks,
    	Charlie
    

    
    	Dan, Down thrust fights wing lift. Often a ship which needs
    considerable down thrust to fly level will balloon when power is
    reduced. This is because the thrust downward counteracting the 
    lift has been deleted and the forward velocity creates the added
    lift to ballon the ship. You are seeing this in the wind because
    you not only have the engine creating forward velocity but also
    the velocity of the wind.
    
    Q: Do you have to run any down elevator when the engine is running?
    
    Q: What is the incedence reading of the wing?
    
    Q: what in the incedence reading of the horizontal stab?
    
    
    						Tom

    Dan,
    
    Au contraire, just the opposite.  On flat-bottomed and/or high lift
    winged ships, downthrust is used to _prevent_ rapid climb (ballooning)
    under power.  If yer' experiencing ballooning under power, my guess
    is that you need _more_ downthrust, not less!  This is especially
    true on very light and/or lightly wing loaded birds.
    
    Ballooning into the wind is common to virtually any/all aircraft
    since airspeed is higher upwind than it is downwind, even though
    _ground_ speed is lower.  Therefore lift is higher when flying upwind.  
    
    This effect is _not_ related to, but is aggravated by, [lack of
    adequate] downthrust.
    
    What you need to do is keep adding downthrust [or reducing positive
    wing incidence, or both] `til, on a calm day, no pitch change is
    observed between power on, power off conditions.  At this point,
    ballooning in the wind can/should be dealt with using elevator trim
    or by holding _slight_ down-stick when flying upwind.    

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

    
    Dan, tell me how your measuring the wing incedence? if memory serves
    me the Pilgram has a flat bottomed wing platform. here is my
    suggestion.
    
    Set the wing incedence up ( by experimenting) so that the ship needs
    no up elevator when the engine is switched off and the plane is
    in essence a glider. Once this is accomplished then adjust the engine
    down thrush down until at full power no up or down elevator is required
    for the ship to fly on the level.  Done this way there should be
    no need for an elevator trim change between engine on and engine
    off.
    
    							Tom

    I am building my first Aerobatic model ( a WOT-4 ) having already
    flown an Aileron trainer from the start. 
    
    Having fitted the fin/tailplane and rechecked the (uncovered) fuselage,
    I have discovered a twist in the front end, forward of the wing seat.
    In other words viewed from the front the wing and tailplane are
    parallel, the fin at 90 degrees but the datum on the front bulkhead is 
    slightly skewed.  If the datum is vertical then the difference in
    hieght at the tailplane tips is about 1/2" 
    
    Hope all that makes sense.
    
    My question is does this matter ? If it does, should I make any
    ( and what ) allowance in the remainder of the building or the 
    trimming.
    
    Thanks in advance

    Mr Conway ( is that Richard? ),
    
    There are a lot of experts around this notesfile who, I am sure,
    can give better advice than I but I am prone for some reason to
    this sort of problem myself -- I wish I understood why!
    
    From your description, your flying surfaces are all in alignment
    with each other -- this is the most important thing.
    
    I can't remember how wide the horiz stab is but 1/2" difference
    tip to tip in relation to the firewall datum does not sound like 
    much to worry about.
    
    Being something of a perfectionist I would normally cut the fuse 
    apart and re-glue -- of course this may not be too easy at the front 
    of the fuse -- I usually make the mistake at the rear -- the type
    of glue used may also make a difference to how easy this is.
    
    So my opinion is it will be OK but I would try to correct it if
    practically possible.
    
    I wait with bated breath to see if I get shot down by the more 
    knowledgeable of our colleagues.
    
    Good luck
    
    Brian
    
    P.S. will you be able to make the meeting at Hampshire House on
    the 31st?