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Invisable aileron and rudder hinges and screws


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One of the appearance items that always bugged me about the canard airplanes, including my own, was the exposed screws and hinges on the ailerions and rudders. They posed a problem during finishing because they are in the way of sanding. My main concern was the apearance.

So, when I built my wings for my new airplane I decided to devise a way to hide the hinges and screw heads. It turned out that the solution was not as hard as it might seem to be. If the hinge line is lowered below the skin surface by .1 inches, the cutout for the hinge can be eliminated. Since the ailerons only move upward 30 degrees this does not cause edge interference if the gap is .06 or more.

The screw heads can be hidden if a small nut plate bracket is used such that the screw heads can be accessed from the underside of the aileron through the ailerion gap when the aileron is deflected upward.

The nut plate bracket is made in a slanted hat section with the nut plate riveted to the top of the hat. The slant of the top of the hat is 30 degrees this gives clearance for the nut plate and screw. The wings or brim of the hat section is about .5 and is used to flush rivet the bracket to the top skin. The only critical part is to make sure that the brackets are placed so that a screw driver has a straight shot to the screw heads.

 

The ailerons are not as easy to remove with this modification because the screws must be removed from under the wing looking up while holding the ailerion up. The smooth unbroken line of the wing and aileron is much more attactive and aerodynamic. The rudders also can use the same brackets. There is no change to the aileron cutouts in the wing or the reinfocement layups that hold the hinges. This means that a completed aircraft or assembly could be modified by adding the brackets and filling in the hinge cutouts.

 

If there is a lot of interest in this mod I will add some drawings of the brackets and installation pictures to our website.

Jack Wilhelmson

www.EZnoselift.com

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I am using Clickbonds. Instead of a head, the screws are attached to round, flat bases. You drill the holes into the aileron spar and rudder spar as per plans, but instead of a screw you flox in a clickbond and glass one BID over that. I wish I had pictures of this on my website. Very clean installation.

 

...Wayne Hicks

Wayne Hicks

Cozy IV Plans #678

http://www.ez.org/pages/waynehicks

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Hi

 

I have seen Jacks hidden hinges on his wings and they really do look good! Add hidden rudder bell horns and it gives the wings a much better (more professional) look.

 

My wings currently have screws on them (but they have not been finished or painted). I am going to go back and mod my wings.

 

I have zipped up all the pdf drawings into one zip file.

 

Enjoy

hidden_hinges.zip

Regards, Nick

___________________________________

Charleston, SC LongEZ, N29TM, 2400 hrs

http://www.canardzone.com/members/nickugolini/

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  • 1 month later...

hi jack, hey I'm working on the hinge brackets and am not quite the metal worker you are, my metal worker is on strike, and I have yet another stupid question.

 

for me, cutting out that shape 56 times seems dificult, but if i make a minor change it becomes much simpler. I would like to ignore the bottom 30 degree angle so that i don't have an "inside" cut(I worried about making this cut 116 times and not stopping perfect and having a weak spot because of a minor overcut).

This would short each side by a triangle that is approx 1/2" x 1/4" x c" squared(too lazy to measure or compute)

 

the plan doesn't show length but it appears to be 1/2"x1"x1/2"(total 2") looking from above

 

could I change the 1/2" to 5/8" to make up for that pesky little triangle's strength?

maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build

 

i can be reached at

 

http://www.canardcommunity.com/

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The brackets can be cut rectangular and trimed after bending if that is easier.

 

Some other comments that may be useful.

 

1. I used AN3 hex hd bolts 3/8" long on the alerions. These can be accessed by using a 3/8" box end ignition wrench on the outboard hinge and a 3/8 " offset box end wrench on the center and inboad hinge. The rudders can use 10-32 pan hd screws 3/8" long.

 

2. on the ailerions the torque tube hole should opened up at the inboard end of the alierion so that the ailerion will have max upward deflection. This makes getting to the bolts easier.

 

I will write up the procedure for mounting the brackets and hinges that I used later.

Jack Wilhelmson

www.EZnoselift.com

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messed around last night and made 1 almost perfect, the ears on my first try were uneven.

 

first I tapped a u shape around a 1" piece of maple, then I clumsily clamped the u shape and the 1" internal maple block and two outside maple blocks at 30 degrees in the vice with my 3 hands. I then tapped with a small hammer and bent the ears over. Had I clamped correctly the ears would have been just fine.

 

I then made a hardwood pocket to hold the u bracket for the last two bends. Will try that out tonight.

 

Piece o cake

 

Well maybe

 

Mike

maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build

 

i can be reached at

 

http://www.canardcommunity.com/

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added a wedge for pocket and sawed a flat opposit for clamping.

 

made a band saw curf 1/2 thickness of aluminum for registration and clamping.

 

tap-tap-tap---piece o cake

 

Mike

maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build

 

i can be reached at

 

http://www.canardcommunity.com/

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  • 2 weeks later...

Some more comments that may be useful.

 

I found that the hinges on the ailerons worked better with the hinge brackets if they are not reversed as called out in the plans.

 

I also found that the hinges on the rudder worked better if they are reversed as called out in the plans.

 

The method I used for mounting the hinges and brackets is as follows:

 

1. Trial fit the hinges and brackets on the aileron or rudder lip. The hinge pin should be directly under the edge. File off some of the front of the bracket to lower the hinge if needed. Check to make sure the brackets will fit on the aileron or rudder lip. If they hit the shear web and are held out too much you can file off the back of the bracket or cut out the shear web in the hinge area and reglass it.

 

2. Place the brackets on the hinge evenly spaced and with the small end of the bracket against the other half of the hinge. Mark the screw holes with a drill inserted through the plate nuts. Drill the hinge with a #10 drill. Fasten the brackets to the hinge brackets and make a final trial fit of the hinge bracket assemblies. The lip edge should be chamfered to .02-.03 thickness( in the hinge area only)fits against the chamfered edge and the hinge pin center line is in line with the edge.

 

3. Put some 3 mil plastic sheet between the hinge and the brackets and reassemble with the screws/ The 3 mil sheet shout be larger than the hinge by .5" on all sides.

 

4. Put a thin coat of flox on the lip in the hinge areas and clamp the hinge bracket assemblies to the lip. Adjust the position so that the Center line of the hinge pin is in line with the edge and below it about the radius of the hinge joint plus .03. Clamp and cure.

 

5. After cure, the problem is how to drill the rivet holes in line with the holes in the brackets. I did this by shinning a small fiber optic light on the holes in the brackets and drilling with a under size drill from the outside where the light spot could be seen through the composite glass lip. After getting the small drill though

the glass in the aluminum hole then the hole can be realigned slightly and then drill out to the 1/8" dia. A penlight and a inspection mirror can also be used to shine a light directly behind the holes.

 

6. The holes then can be countersunk and pop rivets installed. be sure the counter sink is deep enough to allow one layer of bid over the rivet heads.

 

7. The brackets should covered with one layer of bid with flox filling the spaces in between the brackets and at the ends. Wax the screws and hinges and install them over the wet flox and bid and let cure.

 

The aileron/rudder installed by putting some flox on the hinge and putting some foam rubber behind the hinge held in by pushing it down

behind the hinge and clamping the rudder in place until cured. then the hinge can be permanently riveted to the rudder lip.

Jack Wilhelmson

www.EZnoselift.com

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  • 1 month later...

Hi there, Builders,

How about some updates on the hidden hinge screws process? I'd like to hear about your respective progress, in order to evaluate suitibility for my project. Thanks.

 

Terry Winnett

#792

San Antonio, TX

Terry Winnett, Capt, USAF

Cozy MkIV #792

RAF Lakenheath, U.K.

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  • 3 months later...

Well, we have officially given up. The brackets and installation were quite simply taking up way too much time. Making the brackets was time consuming. for us 108 brackets to shape(i made 56) and drilling the holes etc took allot of time. The other problem was i made the brackets slightly wrong! They looked fine, but when we went to install the first set they were too high.

 

The double bend gave me trouble, I didn't think it was a problem, but until you try to install them you don't know. For those of you planning to do it the slope down side has to go to zero. If you made a u piece first then you HAVE to reverse the bend so that the slope ends up flat against the bench.

 

Thanks jack, I'll stick to foam/fiberglass and wood for now

maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build

 

i can be reached at

 

http://www.canardcommunity.com/

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it's not a matter of the attachment process, it's the matter of the forming, it is hard and has to be near perfect on the downward side where there are two bends that meet, there is no room for misforming at this point. Beyond my skill or the moment, if i thought it was important enough, i could start over again and do it right, but it has cost too much time already.

maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build

 

i can be reached at

 

http://www.canardcommunity.com/

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The Clickbond method worked quite nicely. I reported my successes in the Chapter 19 topics area. I've also posted a picture. A more complete "process" write-up with additional pictures is on my website.

 

http://www.maddyhome.com/canardpages/pages/waynehicks/index.html

 

...Wayne Hicks

Wayne Hicks

Cozy IV Plans #678

http://www.ez.org/pages/waynehicks

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