Model & airframe differences

[C150L 6]

Question I asked in another forum. Received no specifics there, just reasons/discussions to use 582s, Jabs or 912s. Thinking about a direct drive auto conversion at this time but don't want redrive either. Maybe Corvair? Helped build one for a friends KR2s and I'm impressed with it.

Perhaps someone here can aim me in the right direction. We're still in the

process of rebuilding what was an Avid before,,, (not by us)

Fuselage has been stretched, wider landing gear made, rudder, elevator and

horizontal pretty well done, still lots to go.

We're still contemplating on a 4 cycle engine. Budget prohibits Rotax or Jab.

Either would be nice, but way out of our price range.

So, I've been reading here and there, but I can not narrow down the differences

in B, C & Mk4 fuselages. I know of some minor changes, such as side and bottom

stringers and a number of other changes, but what I'm wondering about is changes

in the engine mounting and or front end structural changes. I've seen it stated

that from B model on, all the front structures of the fuselage came out of the

same fixture. I don't know how accurate that info is, but read it somewhere.

I've also read there was possible some lower front fuselage reinforcements down

for heavier engines and perhaps Avid supplied 4(?) additional motor mount attach

points which one needed to add to his B or C models for mounting the Soob

engines.

I'm not interested in installing a Soob, but interested on any factory mods to

factory fuselages and/or builder mods done/required for heavier engines.

We have a long way to go, including rebuilding 2 wings to HH spec, but still

want to keep an eye ahead on the engine install/requirements.

Thanks in advance,

Dale

[Av8r3400 1179]

Sent you a private message...

[dholly 718]

Dale,

Steve Winder from [old] Airdale posted the following info to the Yahoo Avid Group some years ago regarding model differences and the changes incorporated into the Mk-IVs. Sounds like you may have found some if this but will repost here to help others.

-Doug

---------------------------------------------

Avid Ser #'s

The Company Light Aero Inc was the original name of Avid Aircraft Inc when it was owned and run by Dean Wilson.

When Dean sold Light Aero to Charlie DeRego, Jerry Matison (owner and founder of Airdale LLC) and Jim Tomash (least said) the name changed to Avid Aircraft Inc. It was around late 1989 and shortly after they moved onto Caldwell airport.

Rule of thumb about ser #'s

A models had Behind Panel Gas Tank, Wheel Barrow type wheels, Cable Brakes, Welded Engine Mount. Wood side and belly stringers

B models had Behind Panel gas tank, Alloy Wheels with cable brakes, Bolt on Engine Mount with Radiator stuck on the outside of fuselage just in front of Passenger door Upto about ser # 250. had a bulge glassed to cowling as air scoop for rad.

C models had wing tanks--some alu some Fiberglass, Matco Hydraulic disc brakes and wheels, Matco Tailwheel with 11/4" tailspring, Bolt on Engine Mount, Radiator inside the cowling at an angle on firewall passenger side. ser #'s 250C-900C Wood belly stringer.

MkIV had Redesigned Vagabond Style Cowling, Front mounted radiators, fiberglass wing tanks, Matco Hydraulic disk brakes and wheels, Maule Tailwheel with 11/2" tailspring, Offset taken out of fin, Offset front mounting taken out of Stabiliser! Steel Tubing Dorsal, Belly, and side stringers. External Baggage Locker.

Ser #'s 900D to around 1550D.

Bandit was a Stripped down MkIV. Ser#'s range as per MkIV BUT suffix"E". There was no difference in Firewall engine Mounting pattern from B models onwards as ALL the frames came from the same jig. Only the firewall back part of the jig changed from B onwards.

Avid sold upgrades from one model to the next, eg Rotax 532 engine Mount/upgrade for A model--as the A model engine mount had to be cut from the A model frame and the Builder welded up the firewall parts some differenes could occur here.

When Subaru installed on ANY Avid, due to extra weight and power extra mount bushings and plates were offered to Avid builder to ADD 4 more engine mount attach points along bottom of firewall. On A,B,C, Models for Subaru extra pieces of tubing had to be welded to the front bottom of firewall to attach these extra bushings / plates.

BUT REMEMBER AND BEWARE----it appeared to the builder that the upgrading of models by adding extra bits of tubing was relatively easy so it was done-- B,C, models are regularly advertised as MKIV's when they are actually "upgraded" earlier versions---there's a lot more to a MkIV than an A/ B/C model and hence increase in Gross weight with MKIV.

Hope this helps clarifies things somewhat.

Regards,

Steve at Airdale

------------------------------------------

Theoretically MkIV's came into effect at kit ser # 1000 BUT it was more like 1100---have the details somewhere.

Anyway....some work for you ---tee hee heee.

Does it have the Taildragger gear legs with the step?

Does it have a 1/1/2" Tailspring necked down to take a MAULE Tailwheel?

Does it have Elevator with inset trim Tab?

Does it have Round Rudder?

Does it have Dorsal steel stringer---i.e Fin tube goes to the T'Deck

FIN NOT OFFSET

Does it have a baggage locker?

Does it have Gas strut fixings just behind left shoulder in fuse frame?

Does it have Triangular steel welded gussets in EACH corner of the "quarterlight window" one gusset is Seat Belt Anchor point.

Does it have Fiberglass seat?

Does it have Spring Loaded Door latches?

Does it have Gusset from Top rear carry thru tube, L&R, outside the fuse side frame, welded to the rear Spar Bolt attach bushing---a bit like a shelf bracket.

Does it have two Strap like Plates welded on Rear Wing Carry thru tube to inside of rear door post?

Are ends of Wing Carry thru tubes welded closed?

Does it have two plates for Fuel Tap behind Vernier Throttle mounting plate?

Are there "glue plates" welded at rear of fuse where inspection plate could be fitted for the elevator Push Pull Tube Clevis Fork end they go from Fuse to Fin Spar.

Are fuselage tubes at this point sort of splayed /opened out for greater Bolt clearance?

There are a couple of other subtle points that can't be checked unless tubes cut -- as Avid upgraded some Tube wall thicknesses to get Gross up to 1150/1200lbs.

BUT These should keep you busy for a short while--- and Send everybody with a "MKIV" running to check!!! heee heee..

Have fun.

Regards,

Steve at Airdale...

Edited 26 Oct 2011 by dholly

[C150L 6]

Thanks for the info Steve, This was definitely a C model. Side stringers metal, belly stringer wood. Tail was offset, it's now straight along with a 16" fuse extension.

Looking at the picture at the bottom of your post, I see the additional 4 motor mount attach points. Is that a MKIV? Have more front end pix? How many of those 10(?) attach points did they actually use for the Sube?

All we started with was bent fuse and wings. Rudder(New) is now rounded. Wings are going to be rebuilt to HH specs and larger dia wing struts. (7/8" I believe VS 3/4 originals.)

It's likely we'll be installing a Corvair. Very close to a Continental but surely less than a Sube.

Thanks again, (everybody)

Dale

[C150L 6]

Doug,

Sorry, didn't notice you posted Steve's other post. Thanks for the info.

Dale

P.S. I dropped you a PM.

[Av8r3400 1179]

Ah, yes. Smilin' Douggy is our keeper of copious amounts of trivia on Avids and Kitfoxes.

I doubt that McKinney (current owner of Avid/Airdale) or McBean (current owner of Kitfox) have as much information on hand as Doug does...

[dholly 718]

Lol, my wife said if there was a 'Hoarders' show for info I just might make the cut!

[lostman 198]

Really good information! Thanks for posting it up. Now that I'm seriously looking to buy one of these birds it is really helping to have this info on hand!

 

Kenneth

[wypaul 448]

Hey Doug that photo shows the plywood inserts in the Seat/landing gear truss rather nicely also.