Alex7403

Hello,

i'm building 60 size airplanes.

The hinges I know so far, and the unique difficulty I have with every kind of them.

• Sig CA hinges (my favorites)
- they are getting stiff – hours to break them in later

• Robart hinge point
- hard to keep one line axis for all hinges => You know you did a mistake and one hinge was 1 [mm] off line when every thing is already glued… (bending with a knock..) []
- most TE’s I met are ¼ width – not much flesh
- because of length the hinge tend to emerge out from the ailerons side
- fear that they are not perpendicular to the surface while gluing
- there is a gap between the surfaces
- hard to keep the epoxy from the axis


• Dubro Nylon Hinges
- Hard to get the epoxy into the slot without gluing the axis
- need to be pined from the outside
- My least favorite


+ I like to hinge first and cover later, this way i cover the gap between the surfaces with monokote => I’m seriously thinking not to use hinges at all and let the monokote be the hinge, well maybe just a small stripe of CA hinge for alignment. already forgot about this!

+ Tips techniques and pictures would be appreciated.

+ I have the GP slot machine, works fine for me.


Thanks
Alex

Chevelle

My Feedback: (2)

Personally, I prefer the Robart style hinges. I build 60 size or 1/4 scale planes and the family of Robart hinges works fine given the amount of "meat" in typical trailing hinges.

I find them easier to use than flat hinges because there is not need to make a flat slit. Just a round hole works just fine. After the parts are built up, I drill small holes where the hinges are going to go and use the very small Robarts but don't glue them in. There is enough grab to hold every thing together and I can take the hinges in and out. Since larger hinges are going to be use and therefore a larger hole, I don't have to worry about the hole when the smaller hinges are taken in and out. I use the smaller hinges right up to covering time.

Yes, I do have to make notches for the pivot point but that notch is much narrower than for the pinned flat hinges. It is easier to make too. Once finished off with a few strokes of my tiny flat file, I enlarge the hole for the final hinge and then cover. I don't use CA for hinges. I use epoxy. When gluing the hinges in, I cover only about 3/4 of the hinge length with the glue. This keep it away from the pivot point itself. I don't glob it on either. I glue one side first, say the aileron. When the hinges are set, it is easy to see if they are aligned by just having them point down (or up). Then can be adjusted before the epoxy is set. Then I glue the aileron into the wing and bend it back and forth. That sets the final depth for the hinges on the wing side.

If a little bit of epoxy gets to the pivot point, that's OK. I don't try to remove it. That just gets it into the hinge more. When the epoxy dries, moving the surface snaps it clear.

I would not recommend using covering as a hinge except for the lightest of planes like some of the park fliers.

vicman

My Feedback: (10)

I use the dubro hinges mostly. I take a paper punch an put a large hole in the center that intersects with many of the smaller ones already there. Then fold the hinge in half to dip the actual pivot point in melted vaselene incase glue gets in there. The biggest diffrence is I use gorilla glue or similar for the hinge. When it kicks off it foams into the large hole forming a rivet and not requireing pinning.

Most of my planes are racers or for high speed. 160 hasn't hurt this type of hinge at all.

Covering for a hinge works fine on small models as already mentioned.

Alex7403

Chevelle,
interesting idea with the smaller Robart hinges, but how do you line all the pivot in one line?


vicman
how do you put the glue into the slot, from my experience its only small amount of glue gets in, and there is a big portion left outside to interfere with the pivot. i know about the vaselene method.

Thanks
Alex

Deadeye

If you are trying to glue in both sides of the robart hinge at the same time, then you will have alignment problems. Here's how I do my Robarts:

1) Plane is built, uncovered, and the holes are made with the Robart jig. Once all 1/8 (or 1/4) holes are drilled, I open a tapered hole for the hinge knuckle to sit in with a dremel sanding cone.
2) test fit the hinges
3) Cover the plane.
4) using a old soldering iron, I poke the hot tip through the covering into each hinge hole spinning it between my fingertips, so it doesn't get melted Monokote all over
5) When ready to glue, drip one drop of water into each hole ( I like to do ailerons, then elevator, etc. Don't get too far ahead of yourself)
6) wait a minute for two for the water to spread.
7) Holding the surface (or plane) so gravity is helping, drip a single large drop of Elmer's polyurethane (or Gorilla) into each hole.
8) let the glue run into the hole. Coaxing it in with a toothpick helps sometimes.
9) Let the glue sit in the hole for 5 minutes of so.
10) Swab out the knuckle area of the hole with a q-tip
11) insert the pre oiled hinge (oil the hinge only!) into the hole so the hinge is exactly half way in. Bend it down 90 degrees to make sure it is perpindicular to the surface. This ensures all hinges are lined up the same.
12) when cured, repeat the process with the mating surface. You may have to tape it in to place.

All done!

vicman

My Feedback: (10)

Alex,
I use a syringe. I heated the end to make it flat, then filed it down a bit to allow it to squeeze into the slot.
Clean-up is pretty simple wipe most of the unused glue from the body and put a small wire in the bottom followed by spritzing some water in there to make it kick. When it dries just snap it out.
The plunger needs to be wiped clean with paper towel. I've been using the same syringe for about two years or so.

The glue will foam out of the slot as it kicks off but won't stick to covering or the hinge with vaselene on it. I use pliers to snap off the big globs and a pointy awl to chip out the remainder leaving a nice clean hinge.

Rcpilot

My Feedback: (78)

Check my build thread on the Midwest Citabria. Aileron hinging begins on page 2 at post #42.

http://www.rcuniverse.com/forum/m_77..._2/key_/tm.htm

I made a jig that rides on the trailing edge. It's got a spacer and guide so the drill bit enters the trailing edge exactly in the middle. If you can use a pencil to mark the holes on the wing and aileron, you can't screw this up.

After all the holes are drilled, I also use a cone shaped dremel tool and run it in enough so the knuckle of the hinge has a place to sit. This is an important step if you don't want 1/4" wide hinge gaps.

I like to glue the hinges in AFTER it's covered. You ever tried to cover a wing with 2 ailerons flopping around? [:-] I usually just use an exacto to cut the holes after the parts are covered. The soldering gun works good too because it seals the edges as it melts the hole.

I glue one side at a time. I rarely try and glue the entire control surface onto the wing all at once. I usually glue the hinges into the wing first. Let them dry overnight and then put the ailerons the next day.

Alignment with Robarts is EASY. Put the glue in the holes on the wing. Slide all the hinges in. Set them at the right depth. I try and set the pivot point about 1/16" from the trailing edge of the wing. This gives a 1/8" hinge gap, which is fine for most 60-120 size birds. Slip the aileron on, but not all the way. Leave 1/4" or more in the hinge gap. Remember, you're only glueing the hinges to the WING right now. There shouldn't be any glue in the holes for the ailerons.

Here's the easy part:
Flex the aileron back and forth to full deflection a couple times. The Robart hinges will naturally swivel around and line up all by themselves. Nothing can bind up. Just flex the control surface a few times to full deflection and watch the Robarts turn to line up perfectly.

When it comes time to glue the aileron onto the hinges, Just drop some glue in the holes and slip it on. Flex to make sure there is no binding. If you did it right yesterday they will not bind. Slide the ailerons all the way onto the hinges and adjust your hinge gaps. Use blue masking tape to secure the control surfaces to the wings until the glue sets. Usually overnight. Next day, take the tape off and test them by flexing. Usually works pretty good.

Alex7403

WOW,
Thanks Deadeye, vicman and RCpilot im learning it now.

Alex

squeakalong

My Feedback: (8)

Being from the "old school; I still use the Sig flat hinges for all my builds. This is so I can cover the hinge line on both mating surfaces with a strip of Monokote prior to covering the entire airframe. I measure the centerline and mark it on both surfaces, say the rudder and fin. Using a #11 blade I cut the slit where required for each hinge. Taking a strip of appropriate size Monokote I apply to the control surface mating edges. Then I cut the corners off each hinge, about 1/8", to facilitate hinge insertion and mark the centerline of each hinge across the short dimension. Insert hinges up to the marked center line on, say, the rudder. Mark two location points centered on the wood over each hinge location and drill completely through the wood and through the hinge with a 1/16" drill. Take round toothpicks and cut each in half; insert each half through the wood and hinge and push down the toothpick until about 1/8 " sticks up. Take a TOENAIL clipper (it makes a clean and straight cut) and carefully cut off the toothpick flush to the wood on both sides of the hinge. I usually use a small hemostat to grab hold of the extra length of the toothpick to keep it from flying around the shop or into my face..BE careful! Now, doing one side of the control surface at a time and one hinge at a time you add a drop or two of thin CA to each toothpick spot and go over the area with some fine sandpaper. The sanding will usually fill any small imperfections and make the area smooth. Flip the control surface over and do the same on the other side.

Now, take the completed rudder that you have toothpicked the hinges into and insert that into the fin which you have previously slotted for hinges, Monokoted the hinge line (which is what I use), and re-slit the hinge locations in the Monokote. I use a metal 6" shop scale placed between the mating rudder and fin for spacing. Push the rudder up to position against the metal scale and mark the two toothpick locations, drill as above, insert the toothpick halves to hold everything in place and finsish off as above. Repeat for all hinges. When finished you will have a very nice, small gap, mating between the control surfaces that will not only look great when you finish covering the model, the hinges will stay where they belong.

In truth it takes longer to describe the process than to actually do it. If you like to use the flat hinges give this method a try for a neat way to install these hinges. Hope this helps.

Soft landings.

Alex7403

sqeakalong, lets see if i got it,
you are drilling through the dry sig CA hinge when its sitting inside the surface and using a toothpick to secure it in place.
Then you add a drop of CA to the tooth pick, and not through the line between the surfaces.

Thanks
Alex

squeakalong

My Feedback: (8)

Alex,

Corrrect. I'm drilling completely through the wood and dry flat hinge, twice on each hinge half. So there would be four drilled holes with toothpicks through them when each hinge assembly is finished; two on the rudder hinge side and two on the fin side x however many hinges you use. I add thin CA a drop at a time per toothpick location and it will wick down and into the hinge and surounding wood. Add CA until it no longer wicks in and wait about thirty seconds. Go over it with the fine sandpaper and presto! Everything works smoothly and stays in place. I do not add the CA through the actual hinge line. I'll try to get a picture of this posted as I have a 4-40 that is done like this and awaiting the Monokote finish. (Got side tracked on my Astro-Hog build)

Be sure to add the CA to both sides of the hinge/toothpick location; that is top and bottom of each aileron or elevator piece and to both left and right side of the rudder, as examples.

Added Edit: a hint...you'll be working with each separate control piece and then the control combinations. When drilling the holes for the toothpicks I always use a piece of scrap 3/4" or so ply or lumber and place that hardwook directly underneath the drilling location so that the 1/16" dia. drill will emerge into that hardwood as it drills through each wood/hinge/control surface. In this way you'll avoid a "ripout" situation in the balsa and the completed holes will be much cleaner with minimal work to smooth them out when finishing each hinge.

Soft landings.

Joe

vicman

My Feedback: (10)

Here is what is left of my T-6 wing after a mid-air that gives you a good idea of what happens in the hinge as the glue kicks.

CRFlyer

The best hinges are IMO the old iron on hinges that are no longer available. However, these can be made out of fabric covering. To make these hinges, get some fabric covering and cut into strips about an inch wide. Then take two strips and run through a sewing maching back to back so that the sticky side faces out on each one. Now all you have to do is pull the glue backing off and iron them on. These hinges are very strong, easy to make, easy to apply, and of course seal the gap.

squeakalong

My Feedback: (8)

I've never seen that on any of my hinge applicatons. Wow! What kind of hinge and glue did you use, Vic, and how did you apply the glue, through the hingeline gap?

Sorry about the mid-air!!

Soft landings.

Joe

squeakalong

My Feedback: (8)

CRFlyer...are telling your age? I used hinges like that in the old CL days and on my early RC planes like the Midwest Tri-Squire in the early '70's. Now that idea brings back a few memories...

Soft landings.

Alex7403

Vicman, from the picture of the aileron the glued section is “beautiful” it makes the disadvantage of 1/4” TE into an advantage.
Maybe from the wing side you don’t need to secure it with toothpicks drilled through?

Thanks
Alex

vicman

My Feedback: (10)

Joe,
If you look at the pics I posted above you will see that I use a syringe and gorilla glue. Any polyurethane glue will work fine. I use gorilla glue since they have little bottles that seem to last longer than the big ones. I wrote a newsletter article detailing the whole process a little more but you should be able to get the idea from my previous post.

Alex, like I said most of my planes are for all out speed or pylon racing so they see some unique action and I haven't had any issues with this method. On most of my faster ships I seal the hinge with covering just for flutter insurance not so much for hinge integrity. I don't pin them either.
The CA hinges are a total pia and I never feel like I get the proper amount of glue on them. I've had them break over time and also seen many of them just plain old pull out, never a good thing.

I thought that pic would make a good point about how well it works. The glue does the same thing in a blind slot sometimes puffing up the aileron or whatever with the foaming action. You may want to use a credit card or something just to spread the glue around but it pretty much fills all the gaps.

squeakalong

My Feedback: (8)

Here are a couple of shots showing my hinging method. As you can see there is not much space within the hinge line...the 6" metal scale is held in place by the control surfaces. Have not had any come loose with this method.

EDIT: WOW!!!! My first photo uploads!!! It works....

Soft landings.

Joe

vicman

My Feedback: (10)

Someone give him a cigarette I think he needs one LOL

squeakalong

My Feedback: (8)

Hey....that's a BIG accomplishment for an OLD F#@T!!! Taking a couple of pics AND showing them all in the same day YEEEEEHAAAWWWWW!

....okay....back to the building......

Soft landings.

vicman

My Feedback: (10)

I didn't know they even had electricity up in Interlochen yet to be honest. You are indeed way ahead of the curve sir!

squeakalong

My Feedback: (8)

LOL!!!! I'll have you know,Mr. Vic, that I, having lived in Alabama for about nine years, was appointed an Honorary Southern Boy 'cause I was told I wasn't "yankeefied" (whatever that means) and the "boys" down there were VERY IMPRESSED that the word "electricity" was even in my vocabulary!!! Told them I drank it all the time from an old Mason jar....[8D]

Soft landings.

Joe

vicman

My Feedback: (10)

Guess you didn't know I grew up in South Lyon, Mi. and didn't have many problems when I moved down here 22 yrs ago. Thats how hickified South Lyon was back then...nowadays all those old farms are bagillion dollar houses.
Learning the trade in Detroit gave me huge street cred when I came here though.

Vic
I got plenty of gojuice in mason jars too.[sm=wink_smile.gif][sm=tongue_smile.gif]

abufletcher

Of course you can always do your hinges the old-fashioned way. The REAL old-fashioned way!

squeakalong

My Feedback: (8)

Hey, Vic, I just KNEW you were an all right guy!! I grew up in Ionia, now THAT was a small town...

abufletcher: VERY COOl BUILD!...those hinges are really nice built like that. Is that a scratch project or kit and what did you use for the nice stab/elev outline? And that little radius piece above the washer in the middle pic is a nice touch. I'm wondering if you are building up one of those "museum scale" non-flying models for display? Nevertheless, what a nice start on your project.

Soft landings.

Joe