Advice on changing to Airframes Alaska Wing Strut

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CRAZEDpilot
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Advice on changing to Airframes Alaska Wing Strut

Post by CRAZEDpilot »

Ordered the struts.... couple quick questions:

1. Does anyone have a handy list of the AN hardware needed? I should install new bolts I think. If no one has such a handy list, it should be the SAME BOLTS listed in the parts book given the Airframes Alaska struts are PMA part right????

2. If no one knows the bolts off hand, anyone know which sheet in the parts book shows the hardware required? I can't find it.

2. Any ADVICE on how to most safely swap in the new wing struts and how to make sure they are adjusted correctly? I can only assume dong it wrong could change the dihedral in the wing, etc.

-Brendan

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gdflys
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Re: Advice on changing to Airframes Alaska Wing Strut

Post by gdflys »

CRAZEDpilot wrote:Ordered the struts.... couple quick questions:

1. Does anyone have a handy list of the AN hardware needed? I should install new bolts I think. If no one has such a handy list, it should be the SAME BOLTS listed in the parts book given the Airframes Alaska struts are PMA part right????

2. If no one knows the bolts off hand, anyone know which sheet in the parts book shows the hardware required? I can't find it.

2. Any ADVICE on how to most safely swap in the new wing struts and how to make sure they are adjusted correctly? I can only assume dong it wrong could change the dihedral in the wing, etc.

-Brendan
I'm not aware of any differences in hardware sizes but you can always get a few extra bolts longer and shorter. Drawing is Wing group 2076F Wing to Fuselage Assembly. You can try and measure exact lengths of each strut and make sure the replacements are the same. That method assumes the rigging is done correctly and you were having no rigging issues. I would recommend redoing the rigging from step one anyway.
Greg Delp
1979 M-5-235C
CT
ATP, CFI, A&P/IA

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Andy Young
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Post by Andy Young »

If your plane flies well now, it is well worth the effort to try to duplicate the current strut lengths. Doing so, if you do an accurate job, should negate the need to re-rig afterwards. I’ve done this on a few planes, with excellent results.

You can remove and replace one strut at a time without having to support the wing, as the wing is stiff enough to hold itself when supported by either strut.

Don’t rely on measuring the struts end-to-end, as these dimensions may vary slightly between old and new struts, and it’s the bolt hole positions that matter.

You can (and I have) do this successfully by very careful measuring of the hole-to-hole distance, but it’s tricky, tedious, and prone to error.

My suggestion is to make a simple jig, as follows:

Lay the old strut flat on a long piece of sturdy lumber, like a 2x10. Make a quick U-shaped bracket for the upper end. Attach it securely to the lumber, then drill holes to match the hole on the strut, and insert a bolt. At the lower end of the strut, drill a hole in the lumber, using the hole in the strut fork as a guide (Drop drill bit through fork, into wood). You should now be able to drop a bolt through the fork and into the lumber. You now have your jig.
Remove the old strut, place the new one in the jig, install the top bolt, and adjust the fork until the lower bolt will drop into the hole in the lumber. Remove the new strut, mount it on the plane, and repeat for the other three struts. To compensate for different positions of the bottom hole for different struts, you can screw a different piece of thin scrap plywood onto the lumber for each subsequent strut.

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Mog
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Post by Mog »

Why not just use some all thread through the ends of the old struts with nuts on both sides to lock the all thread. Then position the new strut so it easily slides on and off the all thread as it’s still tight to the old strut. That way you don’t have to make a new wood jig for each strut.

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Andy Young
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Post by Andy Young »

Mog wrote:Why not just use some all thread through the ends of the old struts with nuts on both sides to lock the all thread. Then position the new strut so it easily slides on and off the all thread as it’s still tight to the old strut. That way you don’t have to make a new wood jig for each strut.
The holes on the ends are in different planes (geometry planes, not airplanes); so I’m having a hard time visualizing how that would work.

maulecan
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Re: Advice on changing to Airframes Alaska Wing Strut

Post by maulecan »

Installed new one too id took same Hard ware than original and adjust same lenght than old one,They fitted ok but not Fairaing must fitted.
i thing lost Cruising Speed by 4to5 kts.ty Christ
onwer to m7235 floatplane since 1996

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