Please place everything wing related in this thread. The following is from Doug Holly.   I built a custom hybrid 'long heavy hauler speedwing' for my Avid+, hoping to have the best of both worlds. I used and followed the Mk-IV Heavy Hauler material and construction method (see both Leni's .pdf drawings and the wing difference explanation below), however, I substituted the flat-bottom Speedwing ribs instead of the under-cambered Heavy Hauler/STOL ribs. The root rib on Avid Speedwing/Aerobat planes is a special 'transitional' rib that matches up to the butt rib (which was always HH/STOL shaped to allow folding wing clearance). In the attached pictures, you can clearly see the differences between the speed and under-cambered rib profiles both on and off my wing.

Also keep in mind, 'Heavy Hauler' was the name attached to several Avid models. A Heavy Hauler B or C model was 1050lbs M.T.O.W. A Heavy Hauler MkIV was originally 1150lbs and then, to compete with the Kitfox 1200, "re-marketed" as 1200lbs. This is the reason one has to be careful around Avid gross weights and wings. In addition to wing length, material and construction differences, the under-cambered HH rib profile was very different from the flat-bottomed Speed rib profile.

In general, Avid Flyer wing differences extend to spar thickness, spar length, lift strut o.d. diameter, airfoil, rib spacing and drag tubes. All wings called for (2) nose ribs between wing ribs, though an additional nose rib per bay is often added on the Speed and STOL wings due to their wider rib spacing. Here are the basic differences between the (4) Avid Flyer wings explained:

  Speedwing: .065" thick 2-1/2" o.d. spars; 108-1/2" spar length; 3/4" dia. lift struts; Avid flat bottom airfoil; (7) ribs ~ 18" o.c.; (3) 1/2" dia. W-2 alum drag tubes; (3) W-3S Short 5/16" dia. alum root rib brace tubes; (1) W-4 Short 1/2" dia. alum root rib brace tube; (1) W-3L Long 5/16" dia. alum tip rib brace tube*; NOTE: Wing tank replaces (1) W-2, (3) W-3S and (1) W-4 alum rib brace tubes at the root end of wing; Key rib dimensions (long rib flaperon hinge) are 35-1/2", 71" and 106-1/2" o.c. from tip rib

Mk-IV HH: .083" thick 2-1/2" o.d. spars; 144" spar length; 7/8" dia. lift struts; Avid undercamber airfoil; (13) ribs ~ 12" o.c.; (1) 1/2" dia. W-2A steel drag tube; (3) 1/2" dia. W-2 alum drag tubes; (3) W-3S Short 5/16" dia. alum root rib brace tubes; (1) W-4 Short 1/2" dia. alum root rib brace tube; (1) W-3L Long 5/16" dia. alum tip rib brace tube*; NOTE: Wing tank replaces (1) W-2A, (3) W-3S and (1) W-4 alum rib brace tubes at the root end of wing; Key rib dimensions (long rib flaperon hinge) are 35-1/2", 71", 106-1/2" and 142" o.c. from tip rib

STOL: .065" thick 2-1/2" o.d. spars; 144" spar length; 3/4" dia. lift struts; Avid undercamber airfoil; (9) ribs ~ 18" o.c.; (4) 1/2" dia. W-2 alum drag tubes; (3) W-3S Short 5/16" dia. alum root rib brace tubes; (1) W-4 Short 1/2" dia. alum root rib brace tube; (1) W-3L Long 5/16" dia. alum tip rib brace tube*; NOTE: Wing tank replaces (1) W-2, (3) W-3S and (1) W-4 alum rib brace tubes at the root end of wing; Key rib dimensions (long rib flaperon hinge) are 35-1/2", 71", 106-1/2" and 142" o.c. from tip rib

Mk-IV Aerobat: .083" thick 2-1/2" o.d. spars; 108-1/2" spar length; 7/8" dia. lift struts; Avid flat bottom airfoil; (10) ribs ~ 12" o.c.; (1) 1/2" dia. W-2A steel drag tube; (2) 1/2" dia. W-2 alum drag tubes; (3) W-3S Short 5/16" dia. alum root rib brace tubes; (1) W-4 Short 1/2" dia. alum root rib brace tube; (1) W-3L Long 5/16" dia. alum tip rib brace tube*; NOTE: Wing tank replaces (1) W-2A, (3) W-3S and (1) W-4 alum rib brace tubes at the root end of wing; Key rib dimensions (long rib flaperon hinge) are 35-1/2", 71", and 106-1/2" o.c. from tip rib

* Applies to wings with wire trailing edge only, not required with metal trailing edge.
  Be aware that wings with the exact same descriptors, ie., STOL wings, may have different Gross ratings depending on when they were sold/built. One thing is certain, there were so many combination of fuselages and wing components bought, built, or cobbed together over the years it can be very difficult to determine exactly what Gross you have unless you physically measure spar thickness, tubing diameter, or even cut a tube to verify wall thickness.
  Wing contruction.pdf