Wing Removal

Discussion for builders, pilots, owners, and those interested in building or owning a Sonex.

Wing Removal

Postby Paul Johnson » Tue Jan 23, 2018 2:04 pm

Today I have been trying to remove the wings on the Sonex I bought last year, as I am going to paint it. I did not build the aircraft but have built several metal aircraft before. The wing removal process seemed very straight forward except for the removal of the cotter pins on the flap attachment push rods. The starboard side was not too difficult, but the port side is another story with its limited access due to the flap lever, after two hours of trying I have decided to unbolt the flap torque tube and remove it with the wing and do the same in reverse when I attach the wing again. Other than increasing the size of the nose rib lightning hole which would require approval here in the UK (difficult) are there any other tips or tricks.
Paul Johnson
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Re: Wing Removal

Postby SonexN76ET » Tue Jan 23, 2018 5:47 pm


Like you, I have the original sized lightening hole in my outboard forward wing rib. I wish that I had done the mod to make it larger. Like you, it takes me about two hours to remove or install the bolt, nut, and cotter pin connecting the flap push pull tube to the torque tube on the port side. It takes a lot of patience. Sometimes you just have to walk away, gain your composure and try again. Next time I have to take my wings off I am going to do the mod to make the access easier. I know this would be difficult for you to get approved in the UK, but some people have actually put an access/inspection panel on the bottom of the wing to have easier access. Anyway, with the standard lightening hole for access, here is how I do it.

To remove the cotter pin and bolt connecting the flap to the torque tube, I recommend the following:

1. Position the flap to a point that gives you the most room in reaching through the lightening hole.
2. Support the flap by placing a cardboard box or something similar under the flap. This should just be a gentle lift to take some of the weight off the pushrod.
3. Remove, if necessary, the flap handle from the torque tube.
4. Use a small pair of pliers or a very small pair of vise grips to grab and remove the cotter pin. I use a tiny, palm sized set of vise grips. Pull and twist the cotter pin to remove it. Discard the used cotter pin.

To reinstall, again support the flaps, put a little bit of grease on the hole in the torque tube where the bolt penetrates it and put a little bit of grease on the bolt. Insert the bolt through the torque tube and the push pull tube. Ensure that the bolt has gone through both the torque tube and the push pull tube (very important). Use your fingers to put the nut on the bolt. Use a small piece of wire to ensure that the castle nut has aligned with the hole in the bolt for the cotter pin. Then insert the cotter pin and gently spread the two legs of the pin and flatten them against the castle nut.

One thing that may help, is to get someone to help you who is relatively small who can squeeze their hands into the access hole easier.

Under the UK regulations, are you able to increase the size of the lightening hole at all? Could you increase the size of the lightening hole and then put a cover over it with the original sized lightening hole in the cover?

Please let us know how this works out for you.

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Re: Wing Removal

Postby wlarson861 » Wed Jan 24, 2018 1:29 am

If the builder installed the bolt with the head towards the cabin and the nut towards the wing tip it is much harder to access than if the bolt is reversed. The lightening hole in the root rib can be enlarged to encompass the two lightening holes to maximize the work room. The factory told me (don't remember who) that some builders have replaced the bolts with hitch pins and spring clips. The bolts carry all their stress in shear but none in tension.
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Re: Wing Removal

Postby Paul Johnson » Thu Jan 25, 2018 12:50 pm

Hi Guy's

Thank you for the replies. I took the wing off with the torque tube attached that gave good access to the split pin also it will be easy to put back together.
Paul Johnson
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Joined: Sat May 21, 2016 1:02 pm

Re: Wing Removal

Postby Ad Eves » Wed Feb 07, 2018 1:05 pm

Hi Paul

What colour scheme are you going for?

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