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Question for varieze owners/builders concerning wing attach plates


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Are the wing attach plates supposed to be tapered?


And what is the diameter for the holes?


I have a varieze project and just noticed the holes for the wing attach plates are all just over 1".

The tapered pins are 1". So this arrangement doesn't work.


Any information provided would be greatly appreciated.

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Here are some pictures of the problem.


The pins are tapered the holes are not.


The pictures show the top of the pin and the bottom of the pin going through the attach plate.


I suppose bigger wa-4 pins could be made but, will the holes be a problem since they are not tapered?



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... will the holes be a problem since they are not tapered?

Yes. Get new plates. The pins must fit in the holes precisely. This was one of the reasons Burt went away from this wing attach design to the Long-EZ method.
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Drop the pin in from the opposite side and double-check - in the picture, you are putting the pin in from the "wrong" side of the fitting. Contact me offline if you wish to discuss options if the bores are truly not tapered. I have a 10-degree included angle mill for cutting the tapered bores (a machine shop would have to do the work), and if there is adequate edge distance ("meat" between the edge of the plates and the closest approach of the final bore), you may be fine.


-Joe Person

EAA Tech Counselor 4418

VariEze N79JN

Bothell, WA (KPAE)

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Uh oh. Chalk me up for a "DUH!". Of course, if the .125 plates did not have tapered bores, the pin installation from the bottom side would not have ended up as the pic showed.


Back up the truck...


If you can acquire a virgin set of wing fittings, you can accurately match drill them to the existing composite spar structure. This entails making some drill jigs using potted drill bushings. Based on the previous post, a good soul has a ste of fittings. If you go this route, email me for specific instructions on ensuring you accurately match all the existing .250 holes in the spar structures. You do not need a machine shop to do this, and I probably have sufficient .250 drill bushings to loan you for the task.


email: ezejoe@comcast.net


-Joe Person

EAA Tech Counselor 4418

VariEze N79JN

Bothell, WA (KPAE)

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  • 1 month later...

He Terry,


Bad situation :envy: , BUT.... :rolleyes:


I mean a recovery/salvage can be performed.:confused:

30 years ago I machined myself thoses wing attaches. Not so difficult.


Here is my suggestion ==> with a conical milling-tool rework manualy the cylindric holes to correct conicity.


Per plans :

Pins taper are 5° (10° included), SIN (10°) = 0.1736

Pins diameter is 1" at maxi (conical),

Total Wing attach tickness is 0.625"

That is to say that diameter difference from top to bottom is

(0.625 * 0.1736) = 0.1085" (= 2.76 mm), very few. 0.0592" on radius !

This diameter increase will not decrease the attach resistance/strenght.

Make new pins, according to larger diameters in plates. Don't worry w 125 000 psi; it's easy to get in mechanical shopflors. My suggestion is to not use tapped pins, all 4 the same, drilled, and use longer bolts w nuts. (so I did)

Have to use "larger" tubing for WA-7 (may be not....).


That all can be performed manualy "in situ" (MUST BE...) They are 4 assemblies: 2 on top and 2 for bottom. Each one will be reworked inependently, but all parts together, that is: (WA-1) + (WA-3) + (WA-1).

To facilite job, it's helpfull to remove WA-3 from wings.....

New pins have to be available first, to "lock" first hole as soon as milled to proced to second.... (not mandatoty, but safer...).

Plans are in section I page 6-17.

Conical milling-tool : 10° (included) suggested. Slightly more is possible (I'm 13°) according to avalaibility.... Avoid less, as you can get an "auto-block" cone system !.......


I hope that can help.







VE 1736

F-PMPZ @ LFPK (France)

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