Conference vmszoo::rc

    I'd look at high frequency vibrations and flutter. Even it you
    can't hear it it's probably there. I use a sig hinge material
    on all of my birds and have never had one fail. It's a mylar
    strip app. 12" long. You cut hinges out to the required size.
    CA and a toothpick do the trick. I'd also suggest you check for
    any movement(slop) in the control linkage and seal the hinge 
    line with clear packing tape or trim monocote.
    
    
    Tom

    Rather than remain ignorant I'd like to ask a related question.
    I think I saw a note which talked about pros and cons of different
    hinge techniques, but can't seem to find it now.
        
    I'm recovering (monokote) a U/C stunt plane, and would like to avoid
    future problems.  I've heard of locking in the hinges with a 
    toothpick but have never tried it.  Does it require installing the 
    hinges before covering, or is there a way to hide the hole made by 
    installing the toothpick?

    
    There are two ways I know. The first being to cut msall circles
    to cover the holes. The second I use is to iron on a strip ti the
    leading edge of the surface and the trailing edge of the wing or
    stab. This strip is just wide enough to cover the edge and overlay
    onto the surface app. 1/4 inch. Then install all hinges and toothpicks.
    Sand smooth and then cover the top and bottom of the wing trimming
    at the control surface.
    
    
    Tom

My thought on this subject of "ripping hinges" is if you keep the gap between 
the control surface and the rudder/stab/ etc as small as possible (ie: less 
than 1/32) there should not be sufficient exposed hinge to rip.

I used to use the tooth pick method as described by Tom in -.1 for years but
for the last 3-4 models have only used white glue (PVA, Carpenters glue. etc.)
as a holding force. The only reason it is simple and quick. The tooth pick is
probably better but I personally feel over kill for the task. 

John

    
    Not familiar with the hinges you mentioned.  Are they the kind with
    a pin in the middle?  If so, here's one thing that I've seen happen.
    When you install the hinge you get some epoxy on the middle pin,
    preventing it from turning.  So when the hinge flexes, it is actually
    stressing the plastic instead of pivoting around the pin.  Eventually
    it snaps in half.
    
    Bill

    These hinges are like the Sig hinges, one piece so I am told..
    
    Rick,

>    These hinges are like the Sig hinges, one piece so I am told..

Careful here.  Sig sells several types of hinges.
I'd be willing to bet a six pack of Colorado coolaid that he is not
ripping Sig "Easy" hinges (or is that EZ hinges?).

Bye          --+--
Kay R. Fisher  |
---------------O---------------
================================================================================

    Sounds like a case of flutter.  It is not often that you are able
    to see or hear flutter, it is more of a high frequency vibration
    than anything else.  There are two things you can do in addition
    to sealing the gap.  First, balance the ailerons using counter 
    weights.  Second, I would guess that you have the tip or end of
    the aileron ending flush with the wing tip.  This exposes the tip
    of the aileron to the rush of air coming from the bottom of the
    wing where the beginning of the tip vortex is.  This can cause a
    twisting motion on the tip of the aileron which the aileron resists
    at some value which induces a form of flutter from torsional 
    vibration.  The way to cure this is to build a tip onto the wing
    and extend the point at which air rushes up from the bottom of the
    wing to somthing that is stable or fixed on the wing.  
    
    Good Luck,
    
    Will

    
    
        I had a close call with my Panic last Friday night. I had flown 3
    flights, and was finishing up for the day. I was wiping the plane down,
    and while wiping the ailerons off, I discovered that 2 of the 4 SIG
    Easy Hinges had ripped clean through on the right aileron. I then
    examined the left aileron and found one ripped clean through. These
    were all inboard hinges, and since I have a one servo/aileron 
    configuration, I didn't have any torque rods to hold the inboard
    section on.
        I have used Sig easy hinges exclusively, and have never had a
    problem before. My Ace-4-90 had 100 flights on it, and the hinges were
    still in great shape. The Panic had 60 flights on it when they ripped
    through. The 2 major differences are that the Panic's ailerons have
    significantly more throw, and the ST-90 vibrates the plane a lot more
    than the 91 Surpass on the Ace 4-40. I replaced all the aileron hinges
    with the new Robart flat hinges, and this seems to have fixed the
    problem.
            
        As a rule of thumb, I would not recommend using the SIG Easy
    Hinges in high throw applications, as they seem to fatique rather
    quickly. They do seem to be fine, and have a long service life
    ( and are much less hassle ) on any application with normal deflections.
    This might seem to be common sense, but I had overestimated the
    strength of these hinges, and some one else may do the same.
    
    
    

    I have been using radio south pro hinges (CA) exclusively for the past
    several years. I have NEVER had any failures even after severe crashes.
    These in my estimation are better than the Sig hinges, as I have used
    both (though no in my planes). Try'um, you'll like'um.
    
    
    
    						Dave