Long-EZ/COZY/etc. Wing Bolt Retention


Marc J. Zeitlin
 

Folks:

We've discussed this type of thing before, but a Long-EZ I'm working on had a particularly nice outer main spar wing bolt retention scheme that makes it very simple for one person to remove and install the wings. All it requires is one small c'sunk drilled hole in the center between the two outer wing bolts.



After the wing bolts are installed in the main spar, this piece is slid over them and a 1/4-28 flathead screw is used to retain the bolt heads; preventing them from turning or pushing back into the spar. The center hole is tapped so the screw pulls it tight against the bolt heads.

The inner bolt still needs to be held in place manually - I install it and wedge it in place with a piece of blue foam until I get the nut started. It might be possible to build a 1/2 version of this part to retain the inner wing bolt - haven't tried that, since wedging with a piece of foam works reasonably well.

While installing the bolts in the spar is reversed from the plans, this scheme makes it far easier to install the wing.

FYI.

--
Marc J. Zeitlin                      marc_zeitlin@...
                                            http://www.cozybuilders.org/
Copyright © 2016                     Burnside Aerospace


Kevin Kelly
 

Neat🌞


On Sat, 14 May, 2016 at 4:10 PM, 'Marc J. Zeitlin' marc_zeitlin@... [canard-aviators]
wrote:
 

Folks:

We've discussed this type of thing before, but a Long-EZ I'm working on had a particularly nice outer main spar wing bolt retention scheme that makes it very simple for one person to remove and install the wings. All it requires is one small c'sunk drilled hole in the center between the two outer wing bolts.



After the wing bolts are installed in the main spar, this piece is slid over them and a 1/4-28 flathead screw is used to retain the bolt heads; preventing them from turning or pushing back into the spar. The center hole is tapped so the screw pulls it tight against the bolt heads.

The inner bolt still needs to be held in place manually - I install it and wedge it in place with a piece of blue foam until I get the nut started. It might be possible to build a 1/2 version of this part to retain the inner wing bolt - haven't tried that, since wedging with a piece of foam works reasonably well.

While installing the bolts in the spar is reversed from the plans, this scheme makes it far easier to install the wing.

FYI.

--
Marc J. Zeitlin                      marc_zeitlin@...
                                            http://www.cozybuilders.org/
Copyright © 2016                     Burnside Aerospace


Marc J. Zeitlin
 

David Froble wrote:
 
As with many things, it's the "idea" or "concept" that is most important.

Precisely.
 
And I agree, it's a great idea.  However, that clunky piece of metal weighs how much?

It's AL - it's a few oz.
 
It seems to me that this part is not structural, and could be much more "flimsy".

This particular one could be, yes - it's machined from billet. Redmon's piece is an extrusion, so is lighter.
 
Perhaps even something removable, just like your chunk of foam?

That wouldn't prevent bolt rotation, which is 1/2 of the purpose of the thing. If you need a second wrench, you need a 2nd person.

--
Marc J. Zeitlin                      marc_zeitlin@...
                                            http://www.cozybuilders.org/
Copyright © 2016                     Burnside Aerospace


Burrall Sanders
 

We've done this a few times since we built our first Berkut and realized that it is a good idea.  Be careful not to use too flimsy of material, we discovered one retainer on a Berkut that let the bolt head spin (half inch all metal lock nuts turn pretty hard) we had to use a handheld hacksaw blade to cut the bolt to get the wing off, trust me you don't want to do that.  But otherwise, yes its a good way to retain a  wing bolt and eliminate the holes in the wing needed to gain access to the bolt heads  ACS sells an extruded AL. channel that is strong enough but needs a small amount of material machined away from the inside to fit the bolt head.
Burrall

www.freeflightcomposites.com


On 5/14/2016 9:32 AM, 'Marc J. Zeitlin' marc_zeitlin@... [canard-aviators] wrote:
 
David Froble wrote:
 
As with many things, it's the "idea" or "concept" that is most important.

Precisely.
 
And I agree, it's a great idea.  However, that clunky piece of metal weighs how much?

It's AL - it's a few oz.
 
It seems to me that this part is not structural, and could be much more "flimsy".

This particular one could be, yes - it's machined from billet. Redmon's piece is an extrusion, so is lighter.
 
Perhaps even something removable, just like your chunk of foam?

That wouldn't prevent bolt rotation, which is 1/2 of the purpose of the thing. If you need a second wrench, you need a 2nd person.

--
Marc J. Zeitlin                      marc_zeitlin@...
                                            http://www.cozybuilders.org/
Copyright © 2016                     Burnside Aerospace