Conference vmszoo::rc

    Maybe we should call this "Sequel to Just for the Wreck-ord".
    
    I've always been amazed at how easy many repairs are despite how
    gruesome they look at the field after the crash.  Since most of my
    repairs seem to be the wings, I'll offer a few comments about some
    techniques I've developed.
    
    Wing repairs (those worth repairing) come in three basic types for me. 
    First is where the leading edge and maybe several ribs are smashed. 
    This is the easiest to repair.  Next is where the spar has suffered a
    crack or is totally separated.  This is a bit more work.  Last is where
    the wing is entirely severed in two from LE to TE.  This is the biggie,
    and I just did one on my Super Aeromaster.
    
    My favorite technique for repairing the LE is to cut it off just beyond
    the broken/crushed area at 45 degree angles.  Then I cut a matching
    piece of LE with the mating angles, sand until it fits just right, and
    CA in place.  I then glue a small ply doubler behind each joint for
    extra strength.  ALso repair and reglue any ribs adjacent to the
    repaired area that were damaged or knocked out of alignment.  Then its
    time to put on the covering and basically its done.
    
    When the spar has suffered a crack or separation, I try to push
    everything back together while the wing is kept flat on a building
    surface.  Assuming this can be done successfully, I CA the joint(s)
    that are so reunited.  Then, using an Exacto knife, I cut out a new
    spar slot on the ribs adjacent to the repaired area so I can add a
    section of spar as a doubler over the re-glued section.  I make these
    about 4 inches long.  After they are CA'd to the original spar and to
    the ribs, the joint is very strong.
    
    SOmetimes it is also necessary to replace damaged or missing shear
    webs.  I find this to be easy to do as part of the above procedure,
    except that where you have put a doubler on the original spar, the
    shear webbing can only be placed  on the other side of the spar, so
    some planning is required to get everything in the right place.
    
    The last technique, that of repairing a completely severed wing is
    really a combination of the previous two techniques.  I start by
    pinning the biggest "good" section of the wing over the plans as it was
    when building the wing for the first time.  Then I pin down the other
    section so it alligns well with the other one.  Next I start cutting
    and disecting portions of the LE, TE, ribs, spars, etc, until I have a
    way or rejoining each broken piece.  This entails lots of added spar
    pieces strengthened with spar doublers, new shear webbing, new sections
    of LE and TE with doublers, etc.  SOunds gory, but in reality, I found
    it to be rather straight forward, and it resulted in a very strong
    repair.  
    
    The alternative to doing all this is to build a new wing, and I always
    find the repair to take considerably less time to do compared to
    rekitting the whole wing.  ALso, its a lot cheaper.
    
    Regards,
    Joe 
    
    
    

    
    This all brings to mind the question I've been asking myself with
    increasing regularity lately:
    
    Why do the d**n manufacturers insist on kitting planes made from sizes
    of wood that I can't buy? For those of us not blessed with a band saw
    this can be a real pain. I've had to order a couple of pieces of wood
    by post in the past, because I couldn't get even close locally, and on
    one occasion I couldn't get the size I needed *anywhere*. This resulted
    in a simple repair becoming major surgery.
    
    Maybe I'll write to the offending manufacturer, and ask if there is a
    real reason!
    
    Cheers
    
    Nigel (who feels better now he's got that off his chest!)
    

    The first thing I do when building a built-up wing is to turn the plans
    over and trace each different rib profile on the back. Then when (not
    if) I  need a replacement rib, it's a simple matter to transfer the
    profile back to balsa.

    Re: .1
    
    That's almost exactly what I go through when rebuilding built-up wings!
    Maybe there's only one good way to skin this cat...
    
    >>>This entails lots of added spar
    >>>pieces strengthened with spar doublers, new shear webbing, new sections
    >>>of LE and TE with doublers, etc.  SOunds gory, but in reality, I found
    >>>it to be rather straight forward, and it resulted in a very strong
    >>>repair.  
  
    True. But the drawback is: added weight. Not so bad for a power plane,
    but if it's a light weight glider, like a handlaunch, all those
    reinforcements add up quickly. I effectively transformed my handlaunch
    thermal glider into a slope soarer by continually fixing the wing
    rather than just building a new one.
    

    First thing I do when I start building a kit is make templates of all
    of the preshaped parts.  It's much easier to make a new one in the
    future if you have accurate templates and it only takes a minute to
    trace the real parts.  I write the type of wood and grain direction on
    the template also.  I have them for most of my planes.  
    
    Charlie
    

Hi,

	re.3 & .5 Yep..I wished I'd done that!! 

	I recently went through a lenghty re-kit, the
trace idea is now firmly embedded.

	re .1 I have been lucky so far only wing tip and
wing seat area repairs..no broken spars TE or LE etc.

	re .2 Nigel I know how you feel, noone seems to
stock all sizes...I end up having to go all over. I also
find it annoying that some thicknesses only come in 4 
inch widths...when I need it wider!!(another joint to
fill and sand!).

Cheers

-Trev (Whose trying to keep battle scars to a minimum).