New HOW TO Posted: How to Install Robart Hinge Points
#52
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Another plane - CoroCub (SPAD Piper J3 Cub) 86 inches wingspan. I used Robart to hinge ailerons. This time, I used Robart hinge glue. It works. On one note, this glue cures quite fast - you have no more than few minutes before you will have problem with moving a hinge in it's hole.
Pictures:
The plane.
Aileron - coroplast skin, balsa LE and blocks for robart hinges.
Pictures:
The plane.
Aileron - coroplast skin, balsa LE and blocks for robart hinges.
#53

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I'm planning a 1/2A Scale Citabria and the elevator requires an 1/8" hardwood dowel for the leading edge, which forms the radius and is also the solo part that joins each side.
I would like to consider using the 1/2A hinge points that Robart offers, but drilling through the hardwood dowel sounds like alignment trouble without even trying.
Any ideas?
Would I have to stack and drill the parts all at once, and then cut, fit and glue in assembly?
How about drilling the hardwood dowel first and using it as a drill guide for the softer balsa parts?
Are other type hinges better in this application? I'm trying to keep the hinges hidden, and want to keep the round dowel idea in its construction, or something comparable if it works better. I just dont know how well the drill would do through all that material if stacked up.
I have a Dremel table saw and a small drill press if that helps with any ideas and trying to keep it as scale as possible.
I would like to consider using the 1/2A hinge points that Robart offers, but drilling through the hardwood dowel sounds like alignment trouble without even trying.
Any ideas?
Would I have to stack and drill the parts all at once, and then cut, fit and glue in assembly?
How about drilling the hardwood dowel first and using it as a drill guide for the softer balsa parts?
Are other type hinges better in this application? I'm trying to keep the hinges hidden, and want to keep the round dowel idea in its construction, or something comparable if it works better. I just dont know how well the drill would do through all that material if stacked up.
I have a Dremel table saw and a small drill press if that helps with any ideas and trying to keep it as scale as possible.
#54
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Already posted this in the Q&A, apologies for the double post.
Does anyone have a method for removing Robart hinge points? I had one on the rudder of my TF Corsair break (terrain impact event, no fault of the hinge!).
I know I can install new ones near to the old but would prefer to remove if possible. Am consider trying a piece of hot wire to melt a pilot hole then drilling the rest out.
Terry
Does anyone have a method for removing Robart hinge points? I had one on the rudder of my TF Corsair break (terrain impact event, no fault of the hinge!).
I know I can install new ones near to the old but would prefer to remove if possible. Am consider trying a piece of hot wire to melt a pilot hole then drilling the rest out.
Terry
#55
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Hi Redback,
The best way to remove a Robart hinge with the least amount of damage is to use a sharpened brass tube slightly larger than the Robart itself and install the brass tube into a cordless drill. Then, carefully drill into the wood around the hinge and wiggle the hinge out after you are done with the drill. Hope that helps.
Happy flying and soft landings!
The best way to remove a Robart hinge with the least amount of damage is to use a sharpened brass tube slightly larger than the Robart itself and install the brass tube into a cordless drill. Then, carefully drill into the wood around the hinge and wiggle the hinge out after you are done with the drill. Hope that helps.
Happy flying and soft landings!
#56

I melt the hinges out. Use your soldering iron with a very long narrow tip. Make sure you melt into the very center of the hinge. Once you have most of the hinge out and the remaining hole is centered, you can use the appropriate drill for the hinge.
If you try to drill before melting out the center of the hinge the drill will just drift into the softer material surrounding the hinge.
BTW poly glue is the weakest of all of the wood glues. (Check the Fine Woodworking test of glues) The strongest is Titebond III which is a type 2 glue. The exception is gluing wood with a high oil content such as teak then use epoxy. This means to me that if I am doing a repair on wood that had some fuel exposure I would use epoxy rather than Titebond III. For a quicker setup time you can use Titebond II with only a small reduction in strength.
With epoxy or woodglue mix a little chopped fiberglass for added strength. This will also slow the glue from dripping out of the hole.
Always glue the hinges to the control surface first. Then while still wet move the hinge to the fully deflected position. Either visually or with a square make sure the hinges are 90 degrees to the control surface. Then let the hinge dry with the hinge down and the trailing edge of the control surface up. I have seen people do the opposite and most of the epoxy/glue slowly flowed out of the hole and dripped off the tip of the hinge point. Wait overnight before then installing to the vertical/horizontal stab or wing. Do the same here. Allow the glue to flow toward the hinge rather than drip off the end.
If you try to drill before melting out the center of the hinge the drill will just drift into the softer material surrounding the hinge.
BTW poly glue is the weakest of all of the wood glues. (Check the Fine Woodworking test of glues) The strongest is Titebond III which is a type 2 glue. The exception is gluing wood with a high oil content such as teak then use epoxy. This means to me that if I am doing a repair on wood that had some fuel exposure I would use epoxy rather than Titebond III. For a quicker setup time you can use Titebond II with only a small reduction in strength.
With epoxy or woodglue mix a little chopped fiberglass for added strength. This will also slow the glue from dripping out of the hole.
Always glue the hinges to the control surface first. Then while still wet move the hinge to the fully deflected position. Either visually or with a square make sure the hinges are 90 degrees to the control surface. Then let the hinge dry with the hinge down and the trailing edge of the control surface up. I have seen people do the opposite and most of the epoxy/glue slowly flowed out of the hole and dripped off the tip of the hinge point. Wait overnight before then installing to the vertical/horizontal stab or wing. Do the same here. Allow the glue to flow toward the hinge rather than drip off the end.
#57


These Robart Hinges may be ok for very large airplanes. I just installed some, but I see a drawback already. If damage is going to happen near hinge it is going to be a hard fix. Also I like the flatt klett type of hinge that can be removed easy if you want to change or repair the control surface. Also a electric a slotting tool makes it fast to install them. Capt,n

#58
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I'm bailing on my first attempt at using Robart hinge points. It's on a 40/60 (SIG LT-40) size plane with 1-piece balsa control surfaces (rudder, elevator and ailerons) that are tapered from 3/8" to 1/8". Both the elevator and the ailerons are pretty narrow - about 1 1/4". I'm using standard 1/8" hinge points. I've stumbled over all of the aforementioned hole alignment screwups and have chalked them up to "time served". The reason that I'm bailing is that the tapered control surfaces are significantly weakened by hole drilled for the hinge point. For grins (evil grins) I held the elevator by the tips (27" long) and very gently pushed out with both thumbs. Crack - broke at 2 hinge point holes. The length of the hinge point from the center of the knuckle to the tip is 1" and with the depth of the control surface being 1 1/4" there is very little room for any error. Yea, and I've had difficulty aligning the drill and have blown out the side of several holes.
This might fall in the "inappropriate application of hinge points" but I would like your feedback as to how to use hinge points or just bail and use either CA hinges or nylon pinned hinges (Dubro std. stuff).
TIA for your feedback.
This might fall in the "inappropriate application of hinge points" but I would like your feedback as to how to use hinge points or just bail and use either CA hinges or nylon pinned hinges (Dubro std. stuff).
TIA for your feedback.
#59
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After reading all of the debate in the previous posts about the proper adhesive for hinge point installation, I decided to do a little experiment. I was preparing for my first installation of the hinge points and decided to practice on some scrap balsa prior to screwing up my new arf. I used a piece of 1/2" square balsa stock and followed the techniques described above including dampening the holes for the gorilla glue prior to installation and using a toothpick to make sure the glue is completely coating the inside of the holes. Picture one shows the setup I made. The two types of glue used was titebond III, and gorilla glue. After putting the setup together I left it alone for approximately 18 hours. After the setup time you can see in picture 2 and 3 what the dried glue looks like on the outside of the holes. Obviously I did not baby sit the installation or clean away the excess glue because I wanted to see how much foam would really occur. The theory on the gorilla glue foaming up and creating a big blob on the backside of the hole doesn't happen, and I would consider this glue to be negligible in the holding strength of the hinge. Picture 4 shows the straps (dog leashes) that I used to pull on the hinges. I stood on one end and pulled on the other with my arms until something failed. As you can see in the 5th picture the tite bond hinge pulled out of the wood, and the Gorilla glue failed at the actual hinge. Upon closer examination of the titebond hinge it appeared that I did not have much glue if any in the hole so I tried again. The results of the retrial can be seen in the last picture as the titebond held as well and the actual hinge failed itself.
Soooooo.... after all of this I learned it doesn't matter what glue is used; it is all in how careful you are in the installation. I was surprised at how strong these things were. Even in the first titebond failure I had to pull very hard to get it to fail. After this experiment I completed the hinging of my ARF, and the process went very smooth and resulted in a good strong free moving hinge with almost no gap at all.
Soooooo.... after all of this I learned it doesn't matter what glue is used; it is all in how careful you are in the installation. I was surprised at how strong these things were. Even in the first titebond failure I had to pull very hard to get it to fail. After this experiment I completed the hinging of my ARF, and the process went very smooth and resulted in a good strong free moving hinge with almost no gap at all.
#60

you can cut the hinge point down to just 2-barbs if needed per the instructions from robart. using their drill jig takes all the guess work out of the placement, but for most trainers and sport planes CA hinges work fine. I only use the robarts when I'm building scale warbirds.
#61
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Where can I order some Hysol for Robart hinges? It looks to be almost the same as Aeropoxy. I have never used either and this is my first attempt at these hinges. The reason I ask, is because if it is made by Loctite than it is probably available at more locations than BVM Aeropoxy at specailty type hobby places. Do I really need to buy the $60.00 dollar gun to push it out of the tubes as well? thanks in advance.
Stangevil29
Stangevil29
#62

Prior to gluing can the hinge be installed and removed as needed during building of the model and to check for proper alignment or does this widen to hole to much?
Is the hinge pin installed mostly flush with the surface or does it stick out some so as to pivot the control surface around the edge?
skeeter
Is the hinge pin installed mostly flush with the surface or does it stick out some so as to pivot the control surface around the edge?
skeeter
#63


A lot of the problems expressed here is alignment of holes for the hinges. I'm a builder and I have learned alot about hinge points and the centering jig that I don't use any more.I don't use points on 40 size planes or some 60 size because they were not intended for those planes in the first place. When building I take all trailing and leading edge feathers, in some cases each one will consist of one or more pieces and I glue the indivdual leading and trailing pieces together (straight) and stack and nail the pairs together with T pins. After they are shaped to their finished size a line is drawn down the center and hinge location marked they are drilled in drill press with proper size bit. Mark ends for identafacation and add them to your build parts. Are you starting to see where I'm going?.
In the end. you use those holes for guide to drill any blocks installed per plans Hense perfect alignment every time. and not only that you use dowles in them to put parts together to finish sanding your mateing parts for perfect fit all around and they can't be made better any other way. In the case of the build is done? just do your best and good luck
Leroy
Plenty here on the glueing.
In the end. you use those holes for guide to drill any blocks installed per plans Hense perfect alignment every time. and not only that you use dowles in them to put parts together to finish sanding your mateing parts for perfect fit all around and they can't be made better any other way. In the case of the build is done? just do your best and good luck

Plenty here on the glueing.
#64

ORIGINAL: skeeter_ca
Prior to gluing can the hinge be installed and removed as needed during building of the model and to check for proper alignment or does this widen to hole to much?
Is the hinge pin installed mostly flush with the surface or does it stick out some so as to pivot the control surface around the edge?
skeeter
Prior to gluing can the hinge be installed and removed as needed during building of the model and to check for proper alignment or does this widen to hole to much?
Is the hinge pin installed mostly flush with the surface or does it stick out some so as to pivot the control surface around the edge?
skeeter
Bob
#65

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Some may find this site helpful on Robart Hinges (hinging):
Also, here are three (3) videos to get you started....
Part. 1
http://www.youtube.com/watch?v=VnBCelaWyP8
Part 2.
http://www.youtube.com/watch?v=R_IKon3CiDM
Part 3.
http://www.youtube.com/watch?v=sny6BT14Zwo
Don't forget to click on each section.... I would have used "Steps(s), but it still works.
BTW: I could not get to the video either????????????

Also, here are three (3) videos to get you started....
Part. 1
http://www.youtube.com/watch?v=VnBCelaWyP8
Part 2.
http://www.youtube.com/watch?v=R_IKon3CiDM
Part 3.
http://www.youtube.com/watch?v=sny6BT14Zwo
I hope that is helpful.... it helped me be most successful with the Robart Hinge.
Regards,
Don
Regards,
Don
#67


Robart suggests useing white glue on theres and I have used 30 min. epoxy also. Alignment is important doing these hinges and I pre-drill all my holes prior to assembly for perfect alignment every time. Holes in both pieces are counter drilled for the pivot head and the tapered surface has a cross sanded relief so hinge will operate without binding. Prior to install I put a drop of 3 in one oil on hinge and work it in then small dabs of vasaline at sides of hinge wiping off any on the post then install all the way in to hinge pin center of the moving part. Glue is put in hole first and spread with a tooth pick and just enough on hinge to fill the barbs. I have never had one bind up from glue getting in the hinge.