Leslie R. Thomas - Avid Model B


61 posts in this topic

Posted

Jim,

The closest that I get to this wing is the Avid Flyer Aerobat, which was a C model, but then the ribs should have been at 12 inches.  The aerobat wing was supposed to be undercambered, like the Heavy hauler, has a 125mph VNE, 110 cruise and a 23'11.5" wing.  It called for a 65" prop, 18 gal fuel capacity (I didn't mention that I have two fuel tanks, a header tank and one behind the seat (I presumed that it was after market).  I got the aerobat undercambered information from the wikia and the test of the specs from a 1989 flyer that I got with the plane.

The gross aerobatic was 850, otherwise the gross was 911.

Sounds awfully close to what I have.  Unfortunately it doesn't list the cabin width.

I think the Aerobat had .083 wall spars too.  ??? EDMO

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Posted

Looking at the finer details of the flyer, I think it must be talking about the C model....it is talking about the fuel tanks being in the wing :(

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Posted

Hate to leave this conversation but storms and lightning here - catch up tomorrow.  G'Night, EDMO

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Posted (edited)

I see in Files and Forms, History of Avid, "Speedwings are 6' shorter than STOL or HH wings", so they should be about 23' 7" span.  That's about 3' shorter than I thought they were.   EDMO

Edited by EDMO

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Posted

Yes, that is also where I got some of my information; information about the Aerobat came from the 1989 marketing flyer that I inherited.

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Posted

Was looking for something else in my pictures and ran across this page on what to level for W & B.  Interesting side point that they say to use blocks on the level on the aerobat wing so it doesn't rock in the middle.  (not undercambered then?)  JImChuk 

Leveling Avid wing 001.jpg

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Posted (edited)

Yes, that is also where I got some of my information; information about the Aerobat came from the 1989 marketing flyer that I inherited.

Joey "C5Engineer", one of the Avid "most knowlegedable" (sp?) on here, along with Jim Chuk "1Avidflyer",  posted a lot of the Avid info in Files and Forms, including the different wing drawings.  EDMO

Edited by EDMO

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Posted

Here is a picture that I took when I initially went to look at it.  These wings look undercambered to me, please correct me if I am wrong.  Where I started off with the aerobat wing was here: http://avidflyer.wikia.com/wiki/Models

Which indicates, under Model C:

"The Heavy Hauler wing rib spacing was changed to 12 inches. The Aerobat wing had the same features as the Heavy Hauler but was 6 feet shorter (24 feet vs 30 ft). The Commuter wing was a short STOL wing."

Maybe I just have a Frankenstein wing where the builder thought what happens if I do this?

20170401_160204.jpg

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Posted

Looking at the picture, I would say the wing bottoms were flat.  You were the one who saw it in person though, so I wont argue with you saying they are undercambered.  If one of the wings was folded back, it would be easy to see.  JImChuk

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Posted

I think the same Jim if you look at the picture in the trailer it is easy to see.  

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Posted (edited)

Maybe one way to tell is to put a level or straight board under the spars on a rib - if it rocks, it is probably Speedwings, and if you can lay it flat across both spars and a curved gap shows above it, then it is undercambered and the Commuter Wing, which I had never heard of until now.  But without 12" spacing and maybe .083 wall spars, it is not an Aerobat.

The photo in the trailer sure looks like Speedwing ribs.  EDMO

Edited by EDMO

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Posted

I don't know if this picture helps or not, but it definitely isn't flat across the bottom,

20170405_083529.jpg

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Posted (edited)

That looks a lot flatter than my Kitfox undercambered ribs which are nearly the same as Avids.  Doug Holly "A+" has posted lots of photos of different ribs showing the comparisons.  I put a drawing of the Kitfox 2 and Kitfox 5 ribs overlaid on each other showing the differences and the modifications I made to mine.  EdMO

Edited by EDMO

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Posted

But it definitely look more curved that the flat speed wing in the earlier picture.

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Posted (edited)

I think Doug Holly A+ built one set of wings using a combination of both ribs?  Some people, like me, have made their own ribs which may not be exactly like the factory ribs. EDMO

Edited by EDMO
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Posted

This, I can completely believe.  This is part of the reason why I am having difficulty trying to determine what limitations / specifications to use with this aircraft with lost log books.

So far, I am thinking a 911 gross, unless the plane comes in REALLY light and a VNE of 120.  I would LOVE a useful load of at least 470.

Any thoughts?

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Posted (edited)

There is no "Gross Weight" on Experimentals, just whatever you have the Cahoonas to fly it at!  Maybe with a little "common-sense" as a guide!

The "normal" Modified Eppler undercambered wings which were used on the Avids and early Kitfoxes seem to hit a "wall" at about 90 mph with the long wings.  Your short wings should do better than that. 

The Avid guys can tell you more about empty weights on them.  I think some have been built under 500 lbs.   I am trying to stay under 800 lbs empty on my "Cross-Alaska Heavy" with larger wings, Four 12 gallon tanks and Subaru engine, Grove tri-gear.   It is definitely not a "Lite Kite"!   ;<)  EDMO

Edited by EDMO

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Posted

The undercambered STOL wing is very dramatic with the curve. There is no guessing if they have the curve or not. I've never heard of a 23' wing with undercamber. You've got an interesting machine. A side note I for appreciate that you are reading the info that is already out there and published and then asking specific questions to the group. This helps to keep the thread on track. When people pop in demanding to be spoon fed info that is easily found with a google search I get frustrated. This forum is great about it but some of the car ones are terrible. 

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Posted

This thread has some really good wing info with pics. Attached is the best I could find with a quick search to compare a bare speed rib to a STOL. 

IMG_7582.JPG

IMG_7583.JPG

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Posted

Because the F/R spar carry-thru bushing measure on all Avid models is 27-1/2", the different style wings are interchangeable (ie., can swap between HH and Speed wings on the same fuselage). Provided, however, that the lift struts match. Early Avids (A and maybe B, JimC would know) had shorter lift struts, while later models moved the lift strut brackets at the spars outward).

Gross of the aircraft would be determined primarily by the wing and lift strut configuration, although other items such as bolts, rod end bearings, landing gear all come into play. See more info on MTOW  HERE. Many (most?) Avids have been modified during their lifetime out of necessity due to lack of factory support, it is entirely possible that a prior owner retrofitted wings of a different rib profile and length than what the original kit was sourced with. Remember, big diff in E-AB world where most anything goes and often does. 

Note: the Aerobat and Speed wing used flat bottom ribs, not undercambered as you stated in a earlier post. The Heavy Hauler and STOL wing ribs were undercambered. See the attached pics of my HH and Speed wing builds, easy to see the rib profile differences when uncovered (just so you don't get any more confused than necessary lol, just be aware that I custom built my Speed wings to HH specs with 12" o.c. rib spacing vs. 18"). For more detailed wing descriptions go HERE
Welcome to AvidFoxFlyers, are you having fun yet? :BC:

 

CIMG5185.JPG

CIMG5965.JPG

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Posted

I think Doug Holly A+ built one set of wings using a combination of both ribs?  Some people, like me, have made their own ribs which may not be exactly like the factory ribs. EDMO

Not exactly Ed... but there ARE (6), yep six!, different rib pieces in an Avid Speed wing. More info and pics HERE

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Posted

Doug,  Kitfox 1 and 2 have shorter liftstruts than later Kitfox models.  Don't think the length was changed on Avids.  Diameter was increased on both makes  as they got heavier. 

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Posted

I am pretty sure the VNE change is more related to the fabric coming off the ribs than gross weight related.  From what Steve Winder had told me at the time I was rebuilding my C HH he said if I rib stitched the wings I could get away with the 120 VNE.  The big caveat here is that in order to get the undercambered wings to 120 MPH you have to have the nose pointed way down hill and lots of power in :lol:  No real reason to ever get to the 120 VNE.  My guess is that you got an early model "cross over" fuse right at the time major changes were being made to the plane.  Some upgrades got in with the package, some did not.  My Mod C has most of the MK IV upgrades done to it but it is still a C...

AS far as the needing to be spoon fed comment.... I can tell from first hand experience that when searching for info you can get inundated with information on a search and talk yourself into thinking something that you maybe shouldn't, hence people asking questions that perhaps the information is out there for someone with more knowledge... Ask all the questions you want here, the search function sucks sometimes and its damn sure not in the good way either!

Wing measurement differences.. could easily have been mistakes by the builder.  Had one wing tip on and realized that he had it shoved to far onto the spar... to make things easy he just did the other wing tip the same and hence yours is a little shorter than most. 

The aerobat had the speed wing ribs for sure..

 

:BC:

 

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Posted

I was just going to start calling this the Johnny Cash Avid....of course no one has gotten the joke yet until I explained it.

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Posted

Jim, I thought someone somewhere had posted the Avid A struts were shorter (and I thought maybe the B as well because of the KF history). I'm sure you're right, you know the early models better than I! Does anyone have the A manual or A wing drawings to post onsite?

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