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Flaperons not lined up

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Posted

The weather was beautiful here yesterday and I was finally able to pull the (new to me) old Avid out of the garage to start working on it. After cleaning the carbs out and checking the coolant an and gear box oil, I got the engine running. I was amazed by how well it starts and runs.

One thing I found is the flaperons are not lined up when the wings are folded and the left flaperon sits higher above the fuselage than the right. IMG_20180421_082627205.thumb.jpg.b263572

IMG_20180421_082635794.thumb.jpg.cb42dde

IMG_20180421_082738591_HDR.thumb.jpg.b85IMG_20180421_131033981_HDR.thumb.jpg.7f1

IMG_20180421_131103939.thumb.jpg.6248666

The right flaperon is about 3/8" above the bearing mount tab and the left is over an inch above the tab.

I don't believe the plane has ever flown and I have not found any bent tubes or other signs of damage in the fuselage. Does anyone know what might be going on here?

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Posted

Hey, the first thing I would do is unfold the wings, level the aircraft (fuselage horizontal & wings level) and then measure (use a water level or an electronic angle ind.) under the third rib inboard, the difference Rh/Lh wing incidence. On your Lh wing strut (wing side, rear fitting) there is an eye bolt you can adjust  to increase/decrease incidence of the Lh wing. I suspect it is adjusted wrong (when new, the wings should be adjusted more or less the same)..This adjustment is there mainly to correct stall behaviour (stall wings level without tendency to roll) I understand. The other thing I would do is a symmetry check where you measure from your wing tips to fuselage tail and see if you get the same measurements. Last and not least you can measure the height above ground (level ground) of your wing tips and compare. All this you do when the aircraft is absolutely levelled.

My 2 cents

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Posted (edited)

I'm editing my post completely.  When I first read it, I thought you were talking about the ends of the flaperons, now I realize you're talking about both ends of the flapeons.  Do like flywise said, set the plane up level in flying attitude, and get out your 4' level.  Swing the wings out.  Check the wings at the fuselage to see if there is a difference, if there is, are both wings the same distance vertically from the wing carry through, or is the top of the fuselage twisted?  Then check the difference in the wings with the level at the rib just inboard of the lift strut attachments.  The plane in the picture flew about 200 hrs, with no problem, and you can see the flaperons are not the same height when folded.  JImChuk

 

Photo0441.jpg

Edited by 1avidflyer

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Posted

Whats with all the washers on that flaperon control Linkage?

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Posted

Good catch TJay, I didn't see that.  Wonder if the angle of the horn on the flaperon is correct??  It is odd also, if the back of the left wing at the fuselage is high, you would expect the end of that flaperon to be higher than the other as well, wouldn't you? Interesting...... JImChuk

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Posted

The left wing definatly appears high,does the turtledeck even fit?Dont be tempted to fly without a good fit with the top and Bottom in the support bearing.

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Posted

looking closely at your installation it looks like the flaperon hinges are not installed on the flaperon hangers the same LH/RH wing (holes drilled wrong in the flaperon hangers...). As a result your LH flaperon sits lower than the RH....

This might also explain the series of washers in the LH linkage to compensate (get the "zero" flaperon setting on both sides).

 

Just another thought.

 

P.s it looks like your craft needs a real good look over  and TLC before flight...

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Posted

They are speedwing ribs, so the mounting would look a bit different from STOL or HH wings.  They are mounted in the center of the rib tail, so I'm guessing that's not the issue.  JImChuk

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Posted

You guys are great! Thank you for all the ideas.

It does appear to me that the left rear spar is too high but I am assuming the fuselage never would have left the Avid factory this way. Like I said before, the fuselage doesn't appear to be twisted or bent but I have not actually measured anything yet.

The stack of washers in the flaperon control rod are to make up for the flaperon being too high.

Dusty, I have a LOT of work to do and intend to completely go through the plane before I fly it. It was inspected and has an airworthiness cert. and I wouldn't think it would get signed off the way it is. I bought the plane with no logs or and information about the history so it might have a story to tell once I dig into it a little more.

Hopefully I will get a chance to measure the fuselage this week and see what is going on.

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Posted

You need to inspect your rib tails very very closely for rot. 

 

E972D263-E4FE-418A-89D6-61C5442AAA9B.jpeg

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Posted

C5, something else I should have mentioned is there is a lot of corrosion on the fuselage tubing. From what I have found so far, it appears to be all surface rust but I will need to go over it with a pick to check for thin spots. The builder did a terrible job painting. I checked the ribs and they felt solid but I will be taking a closer look.

I was really hoping to not have to re-cover the plane but it is probably the best choice so I can do a thorough inspection. 

I'll dig into it more this week and let you guys know what I find.

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Posted (edited)

Several builders have worried about the wingtips or flaperons not being the same when folded - This is not nearly as important as how everything matches when the wings are unfolded in the flying position.  A minor difference of only 1 degree at the rear spar pivot point can make as much as 2.5" difference at the wing tips when they are folded.   I think that the Magnum with Finch tips needs a little difference to keep the tips from touching when folded?

(.017" per degree x inches of length)   .017"x144"=2.448"   EDMO

Edited by EDMO

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Posted

Ed, I was thinking the same as I was working on the plane yesterday, but the problem is the wing and flaperon are 1" off at the wing root where everything should be fixed to the fuselage and square. You are correct though what really matters is how everything measures up when the wings are unfolded.

My other worry with this plane is there is corrosion on the fuselage, and poor workmanship throughout and I am not able to fully inspect the wings as they are covered. I will need to find a good A&P to help inspect the plane but I need to see if it is even worth going that far.

If all else, it makes a great lawn ornament. I had three random people stop by as I was working on it. Not one of them had any desire to fly with me :)

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Posted (edited)

"a good A&P" must be one familiar with tube & fabric planes, preferably Kit-Planes - lots of them only know about factory spam cans.  Another Avid/Fox builder might be as good or better than an A&P.  Take your time to evaluate it - it may not be as hard to fix as you think.  Good Luck,  EDMO

Edited by EDMO
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Posted

I took some pictures of the Avid A model today, and while I was at it, I snapped a couple of pics of where the rear spar attaches to the wing carry through.  Notice that the tops of both of the verticle tubes that the rear wing spar attaches to.  When you were showing the picture of your flaperons being different heights, I wondered if one of your tubes is higher than the other.  That would lift the back of the wing and the flaperon if one side was higher than the other.   Anyway, something to look at.  JImChuk

 

Photo0496.jpg

Photo0497.jpg

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Posted (edited)

Jim, thanks for taking those pictures. I don't believe that is the problem with mine.

I spent some time last night with a water level to get some measurements. Here is what I have so far:

Airplane_Measurements_Snip.thumb.PNG.935

I leveled the fuselage and used the water level with a yard stick with 1/16" precision to get the measurements. I need to re-measure the flaperon bearing plate again, but otherwise the measurements should be fairly accurate.

 

Part of the problem is the flaperons were not mounted correctly and the left flaperon is mounted higher than the right. You can see it in these pictures.

IMG_20180423_215128276.thumb.jpg.70bed46

Right flaperon mounting at wing root

 

 

IMG_20180423_215144262.thumb.jpg.99dbc95

Left flaperon mounting at wing root

 

I'm thinking I might fill the holes with thickened epoxy and remount both flaperons. I looked through the construction manuals and found the flaperon mounting instructions. The instructions in the C-Model and MK-4 differ.

Model_C_Flaperon_Mounting.thumb.PNG.7974

This is from the C-Model instructions. It specifies 54 degrees from the top surface of the wing.

 

 

Mk_4_Flaperon_Mounting.thumb.PNG.901e57e

This is from the Mk-4 manual. It looks like they say to measure the 54 degrees from the extended wing rib. Maybe the measurement is not critical as long as they are the same on all of the ribs?

 

Anyway, I believe the reason the flaperons do not line up when the wings are folded is a combination of the improper flaperon mounting and the left wing trailing edge is a little higher than the right. I should be able to fix the flaperon mounting but is the difference in the trailing edges on the left and right wings a cause for concern?

 

 

 

 

 

 

 

Edited by cr125r847

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Posted

Sent you a private message.  JImChuk

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