Fat Avid

[Marshawk]

Thanks Jim ,I'll check that info out when I go look at it, I believe he says it is a heavy hauler registered as a Model C, thats were I came up with the 1050 ibs gross

Thanks Willis

[dholly]

Willis,

1.) Please do take Jim's advice. There were so many combinations of Avid fuselages and wing components bought, built, or cobbled together over the years it can be very difficult to determine exactly what M.T.O.W. you have unless you physically measure spar thickness, tubing diameter, or even cut a tube to verify wall thickness.

Again, for anyone interested in the Fat Avids, it bears repeating for safety sake... when Airdale LLC sold an Avid Plus frame as a Fat Avid upgrade, they clearly stated that the gross weight of the upgraded model was as per the existing Avid wing construction. So, while the Avid Plus frame etc. was designed for a gross weight of 1250lbs., if you fit a STOL wing from an Avid A model gross weight of the Fat Avid would be 850lbs., fit a HH wing from Avid B/C model and gross weight of the Fat Avid would be 1050lbs., fit a STOL wing from Avid MkIV or Bandit and gross weight of the Fat Avid would be 911lbs-1000lbs. Fit a Avid MkIV HH wing and gross weight of the Fat Avid would be 1150-1200lbs.

In case anyone is confused by all this... the Avid Flyer wing differences that affect M.T.O.W. extended primarily to spar thickness, spar length, lift strut o.d. diameter, airfoil, rib spacing and drag tubes. In general, the STOL and Heavy Hauler wings used long spars with under cambered ribs, while Aerobat and Speed wings used short spars with flat bottom ribs. All wings called for (2) nose ribs between wing ribs, though an additional nose rib per bay was often added on the Speed and STOL wings due to their wider rib spacing.

The name ‘Heavy Hauler’ was attached to several Avid models but actually came about with the later Avid B and C models. Those kits only had the .083” spars and larger 7/8” lift struts. Ribs were spaced every 18" o.c. which meant only one short rib between the long ribs acting as flaperon hinges. The M.T.O.W. of these B or C model HH’s was 1050lbs. Very late Avid C models could be ordered with HH wings which had .083” spars and two short ribs between the long ribs. Ribs were spaced every 12" o.c. but M.T.O.W stayed the same. The Avid Mk-IV HH also had .083” spars, ribs 12" o.c. with two short ribs between the long ribs plus other changes, and was originally 1150lbs. and then, to compete with the KF 4-1200, "re-marketed" as 1200lbs.

Here is a little more detail from a post I made on the Avid Group a few years back:

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.

2.) Finally, I can't help but add my .02 cents on the deal. For all you mention, that sounds like a very good price IMHO. And -bonus- it's 85% done?! IIRC, the Fat Avid upgrade package was priced somewhere around $5-6k, and the complete Avid Plus kit around $15-16k without FWF and instruments (I bot my complete kit second hand).

Personally, I would buy it and sell off all engines and the Avid frame with wings, together or separately. Heck, that's a fair chunk of change and somewhere there is a need for those parts. Then I would buy new HH wings and struts from Airdale to bump the M.T.O.W. to 1250lbs. (or, a bit more with simple spar stiffener mods) and start a new engine penny jar. Keep an eye out for a used 912ul while you build the wings, or buy some Lotto tickets if you want a new one. Or, sell everything and put a used 912 on the nose now to pick up some useful load and fly with the 1050lb. wings while you can locate or build new 1200lb. wings.

Lotsa options! With a little effort you could have a 90% new, wide cabin LSA with higher gross than a KF 4-1200, all in relatively short order for a net investment of ~$20k. Perhaps well under if you luck into a really good used engine bargain. OK, going to take off my cheerleading skirt now. If you still have my tel# and want to talk just give a shout.

Good luck!