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Building Tips and technical articles. => Building techniques => Topic started by: Dennis Toth on July 06, 2017, 04:49:03 PM
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Guys,
Working on my Barnstormer and getting to the point of putting the elevator/stab together and was wondering what others have used for hinging the thin 1/8" stab/elevator? I have used small R/C plastic pin hinges. These are tricky to get in but work. I have also used the sewn iron down, this gives a sealed hinge line but I get nervous about them holding together in stronger winds (like we always get here in FL at second round in contests). There is the old fabric hinges and tube/wire types.
What have you used?
Best, DennisT
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Dennis,
I used the Klett flat hinges on these models with only 1/8" balsa elevators.
Du-Bro also makes them and they are available although the Klett hinges are NLA.
If you elect to use this hinge I'll get them to you.
As you can see from these photos, they just about disappear. Takes a bit of doing to recess them as I have, but the look and results are worth it.
Charles
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For get those plastic hinges, go with the old tried and true cloth over and under hinges. Go full span with them and you don't have to worry about sealing the hinge line.
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For get those plastic hinges, go with the old tried and true cloth over and under hinges. Go full span with them and you don't have to worry about sealing the hinge line.
I agree! y1
Jerry
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The few times I've tried cloth hinges I always felt that I was juggling too many things. I'd probably either gird my loins and go ahead and do cloth, or I'd do sewn hinges.
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If you have access to a CAD program & laser cutting, make a center layer from 1/32" with the hinge pockets already cut out, and put 1/16" top & bottom for a total thickness of 5/32". Hinges absolutely aligned, plus you can make lightening cutouts wherever else you need them.
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Guys,
I have considered the full length cloth over under but am not sure if I feel confident they can handle the high forces on the hinge line in higher winds (that we almost always have in the second round of contest day). I like the built up approach with the hinge pockets, here since its stab/elevator is very thin seems the weight of the glue the top/bottom sheeting could be significant and may be to much.
Has anyone used brass tubing sections with a cloth/fiberglass tape warp? This would look a little like cloth hinges but would also create a sealed hinge line and allow the elevator and stab to be finished apart. With most OTS ships you need some tail weight so the brass tubing and wire should not be problem. It will take a bit of planning to secure each section to it's respective part without gluing the tubes to both sides. I'm thinking that strips of wax paper behind the side not being glued. Maybe I can set it up and if each section of tubing is say 1" could put a single drop of epoxy on each tube to set them in place. After they are set the pieces could be separated and final gluing could be done with the glass tape strips.
Best, DennisT
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I had that sew continuous sewn cloth hinge. Tried it on one plane and after wards when I needed hinge material I would remove the sewn thread from the material and cut for individual hinges. The secret to them even though time consuming is to put several coats of dope on the hinge lines of both surfaces. Thin put the hinges in place with very, very thin dope. You not only seal the hinge line , you fuel proof it also using butyrate dope from start to finish on your plane. I have no nitrate in my shop as I got it mixed up one time and what a mess it makes when you put nitrate over butyrate. If you do a search on some of my construction photos you will see my way of hinging control surfaces.
I did the Nylon hinges on the B-25 because of the lucky boxes as they are called. Nothing like tapered wings wit dihedral breaks. D>K
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the fuzzy Mylar plastic strip hinges work fine on smaller, lighter planes such as the Barnstormer. About 8-9 evenly spread along the stab with CyA glue. No problems with aligning hinge pins. The plastic always bends along the hinge line.
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Phil,
I tried the Mylar hinges but they are a little stiff for a light ship and causes some hunting.
I am going to use the tube and wire type hinge. So the question is brass or copper tubing? I have both that the 0.014" wire fits. It seems to me that the brass is a tougher material for the bearing. The objective is to have a very smooth sealed hinge (without tape) that is long lasting. So what material?
Best, DennisT
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Phil,
I tried the Mylar hinges but they are a little stiff for a light ship and causes some hunting.
I am going to use the tube and wire type hinge. So the question is brass or copper tubing? I have both that the 0.014" wire fits. It seems to me that the brass is a tougher material for the bearing. The objective is to have a very smooth sealed hinge (without tape) that is long lasting. So what material?
Best, DennisT
Dennis,
Myself and other guys have used brass with aluminum tube inserts the full length for ailerons in R/C.
Could work for elevators.
CB
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Quick answer is APC sourced Carbon tube
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Longer answer
Denis I compared a full length tubing method I saw here on SH on a relatively narrow width Ringmaster Stab/Elevator by comparing the raw wood, cloth hinges, klett style, music wire and brass tube, music wire and aluminum tube, and music wire carbon tube.... as can be guessed each variation has a different weight of the raw materiel
I ended using the carbon tube and wire once I determined I did need a LITTLE tail weight ( semi scientifically predicted)....if the planning has suggested tail heavy I would have chosen the cloth or sewn hinge method
The biggest problem I had was jigging up the carbon tube so all were centered and aligned and NO Glue could foul the whole shebang...like my first attempt
In essence I put a 1/64th shim under the tube to set center, put the tubes and wire in place and taped top side, flipped, set back on shim to re-establih center, then carefully tacked each (every other) tube to the stab or elevator in only the very center of the tube with a 1/4" lay of SigMent ( fairly easy to sand)
Carefully took it all apart.... then CA each tube in place, and let cure...flat bar sanded down the semi proud thicker SigMent glue spots
At this point the tubing I used was a smaller diameter than the thickness of the stab/elevator... epoxy micro balloon mix and each tube second gluing blended as a sort of fillet in the tube to wood contact...
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Hope it holds up for you. As if you had seen some of the early tube and wire set ups there was cloth wrapped around the tubes to hold them solidly against the surface they were attached to. D>K
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I also use the tube and wire system. I like the looks and the hinge is very free. I use 3/32" dia aluminum tube cut into 1" lengths to cover the length of the hinge line. Tip pieces are approximately 1/2" long. I align all the tube pieces on a piece of 1/16" diameter music wire. After scribing a slight center grove along the hinge line with a pencil or ball point pen, I position the tubes and wire assembly along the hinge line of the stab and tack every other tube in place with medium CA. I then position the elevator and do the same. After gently pulling out the wire, I separate the stab and elevator and CA the tubes permanently in place. I then glue a piece of polyspan over the tubes with Sigment. The Polyspan grain needs to be perpendicular to the tubes. After finishing, the polyspan is invisible. I use 0.047 music wire for the final hinge wire. Sounds more complicated than it is. This picture is from my Ringmaster.
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Jim,
I think this is the approach I was looking for. I had been thinking about how to secure the tubes so that it is a strong hinge for those second round winds. I like the polyspan wrap, its easy to cut cleanly, thin and strong. I had thought about fiberglass tape or silk or cloth, these seemed a little thick or would fray around the edges. Thanks for sharing those details.
Fredvon4,
I like the carbon tube approach, let us know how it holds up. Your process is well described and I think it is the simplest way to get this attach. I think that Jims polyspan wrap seals the tube a little stronger. Your 1/64" shim is what I was dry fitting yesterday to get a idea of how to center the tube on the 1/8" stab/elevator, worked well good idea.
Best, DennisT
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On all of my small things like that now, I like and prefer a sewn hinge. Lightweight, very flexible and very easy I find.
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Jim, Fredvon,
How did you secure the wire and to which part? I think it should be a small L on the inside side with the non moving tube against it. I would like to keep it removable to allow easier painting.
To cut the tubing I picked up a 2" Drillmaster cutoff saw from Harbor Freight item 62136 I think is was $39. I found a cutoff wheel with the 3/8" shank at http://www.foredom.net/ad11.aspx, Item Number A-D11 $3.20. Once I cut the tube to 1" pieces I cleaned off and smoothed the edge to have smooth movement.
Chancey,
I have used the sewn hinge on my 30 year old ringmaster and it has worked well, gives a totally sealed hinge without tape. My concern is that at contests here in FL when you get to late morning for the last half of round one flights and into round two the wind comes up to 12 plus mph. The ship starts to get pushed and this puts a lot of stress on the elevator hinge. I feel that the hinge could fall so that's why for OTS contest ships with the 1/8" stab/elevator I like the tube/wire/wrap approach.
Best, DennisT
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On my hinge wire--- I bent about a 1/4" 90 degree leg. The wire gets inserted from the inboard side and the little leg gets secured to the elevator with a small piece of tape during testing, then MonoKote.... I did not bother to inset the wire leg into the stab or elevator tip.... so it just sits a bit proud and is very easy to remove and stays put for each flight so far
I actually got this idea from jfv above; back when I was searching around the site for RingMaster ideas. I did one exactly like shown above with CF. I added the CF after the hinge tubes were glued and carefully formed the CF over or between each hinge tube. BUT I screwed up the reliefs between every other tube and after glue, sanding, filling, dopeing, and final finish--- the offset of each tube made for a not so free swinging hinge line...pretty stiff
The one shown without any attachment other than CA and Epoxy is on a RM that I fly only about twice a year and I do not have the ability to do much more than simple sport flying with any of the more violent maneuvers like square corners
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Same way as Fredvon. About a 1/4" bend on the inboard side, secured with a small piece of scotch tape. If the hinge gets a little tight after finishing, just use a smaller diameter wire. I have used as small as 1/32" diameter wire without any issues.
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Always a handy video Dubro's Kwik Hinge Slotter https://www.youtube.com/watch?v=ApVHQgNvstU
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Guys,
OK, have decided the wire/brass tube hinge with the polyspan wrap is the way to go. A few observations if you use this approach. First the cutoff tool (see below in this thread for details) is great, it gives a clean cut with the cutoff wheel (not the saw blade it comes with). Once you select a length for the tube sections (for mine it is 1") make a gauge that you can use to get the same length on each cut (I used a 1" sq piece of scrap). Once you cut the tube pieces clean off the edge on either the cutoff wheel or a piece of sand paper to take off any roughness. Use your finger to check the smoothness of each edge. Slide each tube on the wire and check that they roll smoothly against each other with a little pressure pushing them together (this is a pain but if there is any sticking it will cause the ship to hunt).
To install follow JFV's process outlined earlier in this thread.
Best, DennisT
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Are you using brass? I use aluminum.
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JFV,
Yes, I am using the brass, I had it on hand. I can use the tail weight.
Since this is a take-a-part I plan on doing another fuse with electric and might do a new elev/stab might use aluminum on that one since I can position the battery to adjust the CG and would need to save all the weight I can as the battery is the heaviest part.
Best, DennisT
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Brass works fine especially if you need the weight. Just finished my new Ringmaster and did the hinges the same way. Very happy with the results..
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Are you guys leaving space between the tubes length wise? Is that the 1/64" spacer spoke of?
I have a 1/8" stab/elevator to do on my .15 Magician and I think that a tube type hinge, be it aluminum or carbon, and secured with glue and covered with Mono-Kote might be a good way to go.
Thanks in advance
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I don't do anything specific about the spacing between pieces along the length of the hinge line. I just put the pieces on the wire and glue in place. Also, I think the glue and monocote should work. Just get the monocote nice and tight around the tube. I'm assuming you are going to have separate pieces around each tube then a final piece over the surface.
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I thinkyou are way over thinking and over engineering a simple part of the Ringmaster. I have never seen a sewn hing fail, nor have ever heard of one failing. If we are talking about a 1/8" stab/elevator on a Ringmaster, if the balsa doesn't fold on a maneuver, the sewn hinge will hold. Just use good strength carpet thread. I have read where 1/2A flying line is the favorite choice. I think four decent sewn hinges on each side will out last the rest of the airplane! Barrel hinges on 1/8" balsa , no matter how neatly installed, doesn't leave much meat left for stress and strain. One tweak on a cartwheel from a rough landing and they will rip out. If you are entering OTS contests, you can't change the thickness as per the rules. If you go with the tube hinges, I would recommend a slight gap between the tubes. Space them with little bits of paper or card stock that can be torn out after assembly. Sitting in the sun, you may be surprised how much they may grow and bind. Dust and dirt will get in no matter what you do, and a decent gap will allow it to work it's way out also or allow you to clean it. If you fly this model a lot, I will be interested in know how much vibration affect the wire/brass joint and if any metal gets hammered and they get sloppy over time.
Type at you later,
Dan McEntee
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If you go with the tube hinges, I would recommend a slight gap between the tubes. Space them with little bits of paper or card stock that can be torn out after assembly. Sitting in the sun, you may be surprised how much they may grow and bind. Dust and dirt will get in no matter what you do, and a decent gap will allow it to work it's way out also or allow you to clean it. If you fly this model a lot, I will be interested in know how much vibration affect the wire/brass joint and if any metal gets hammered and they get sloppy over time.
I haven't seen them do that, in limited experience, seem to be pretty reliable.
Brett
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I don't do anything specific about the spacing between pieces along the length of the hinge line. I just put the pieces on the wire and glue in place. Also, I think the glue and monocote should work. Just get the monocote nice and tight around the tube. I'm assuming you are going to have separate pieces around each tube then a final piece over the surface.
My intent was to wrap one piece of monokote from top to bottom of the elevator, around the tubes, and then seal and overlap the elevator trailing edge.
On the stab, the same thing, but overlap the leading edge.
Then go back, trim the film with a split where there isn't a tube, and tack it down there.
The only issue i can see possibly happening, is the film causing binding on the other tube by adding thickness. If i use a wire (or another tube) a good amount smaller than the hinge tube ID, then it should allow for this extra thickness.
There is a way to make a slick, non-beveled, gapless and free monokote hinge that I've never seen done, but it's labor intensive, and two layers of film are needed.
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My intent was to wrap one piece of monokote from top to bottom of the elevator, around the tubes, and then seal and overlap the elevator trailing edge.
On the stab, the same thing, but overlap the leading edge.
Then go back, trim the film with a split where there isn't a tube, and tack it down there.
The only issue i can see possibly happening, is the film causing binding on the other tube by adding thickness. If i use a wire (or another tube) a good amount smaller than the hinge tube ID, then it should allow for this extra thickness.
There is a way to make a slick, non-beveled, gapless and free monokote hinge that I've never seen done, but it's labor intensive, and two layers of film are needed.
Right, you take two strips, stick them together at the edge with about 1/8" overlap, and iron them adhesive-to-adhesive. Then cut them into 3/4 wide strips, and apply them like over/under cloth hinges. It's shown on the Tutor plans, among other places. I don't recommend it.
Brett
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So, you've done that, and it doesn't work? In theory it should work well, but I've never tried it. I don't like that it doesn't end up with the parts covered completely, and that I'll have to add another layer of monokote on top of that.
With what i was going to do with the tubing, one layer gets it all done.
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The Monokote over/under hinge method was popular in my early R/C sailplane days. It was a way to get a sealed hinge the same color as the rest of the surface. it was tricky to apply, as you have to have heat just right, and keep in mind that he material can and will shrink. This caused problems if not corrected. I never tried it just because it looked so tedious. It kind of went away when speeds on sailplanes started climbing and full flying stabilators became the norm. I don't think I have ever seen anyone use it on a stunt model.
Type at you later,
Dan McEntee
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I've used the over/under moneycote hinges on profiles & 1/2A's and plan to use it on my Barnstormer - if I ever finish it. I cut the hinges 1" wide and place them side by side for a continuous sealed hinge. Works very well on thin surfaces, seems very free and very durable.
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Guys,
Working on my Barnstormer and getting to the point of putting the elevator/stab together and was wondering what others have used for hinging the thin 1/8" stab/elevator? I have used small R/C plastic pin hinges. These are tricky to get in but work. I have also used the sewn iron down, this gives a sealed hinge line but I get nervous about them holding together in stronger winds (like we always get here in FL at second round in contests). There is the old fabric hinges and tube/wire types.
What have you used?
Best, DennisT
Hello Dennis
I use plastic hinges and to do hinge slots I made a small tool with a #11 blade glued to 1/16 balsa so about 3/8 of the blade would stick out the I glued another piece of 1/16 to sandwich the blade. I practiced on a piece of scrap balsa to make sure I was making the slot in the middle of the edge,I had to sand one side of the 1/16 balsa to get the blade centered. I placed both the elevators and tool flat on my working board and did some shallow passes until all the tool blade was in. I deepened the slot as necessary with my xacto. they came out nice but needed some enlargement to be able to fit my plastic hinges. I took a piece of 1/64 plywood and using scotch double sided tape I stuck a piece of 400 grit sand paper only on one side. With that I sanded the slot to get the hinge to slide in to avoid having a bump where the hinge is on the elevator/flaps. The advantage of having the sandpaper on one side is that it slides in easier plus if you have to move the slot to center it in the surface it will only sand one side. Here are pics.
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Back a bit I had seen a photo essay or video on the monokote hinge... perhaps from Dane Martin but really can't remember.... I followed the fiddly method and thought dang this looks very good and NO gaps.... BUT on a 17" wide Ring Master Stab and Elevator it was self leveling...not very fall free at all
Perhaps not a problem with that bird, but I did not like it and saw jfvs method...tried it.... and I guess lucky cuz it is gapless, very very loose, and has so far survived every one of my early arrivals....not so other parts of the plane
I did do one other of the tube type with CF veil for better tube to balsa support and only issue was my method was as noted above, made the offsets between the Stab and Elevator create a slight bind with the correct sized wire... smaller diameter wire solved that, but what I used was a bit too small...what I had on hand.... so a little too sloppy but good enough for my hack flying
What I do know is that all CA type hinges are much too stiff for my liking, and I do not have the ability to make sewn hings look pretty ....same with over under cloth
Way back in the 60s my Dad had a brilliant idea cuz cloth hinges what were in all the kits--- but like me ---he hated the look.
So he set to use the entire length of provided hinge materiel by drawing a crayon mark down the center of the strip both top n bottom then candeling the wax carefully into the fabric.... not so much for keeping glue out but the later dopeing
He then built a 1/2" Stab trailing edge and Elevator Leading edge from Balsa strips that equaled the thickness of the real stab and elevator minus 1/8th with the lengthwise cloth only glued to the balsa inside about 1/8th inch of the front and back edge of the cloth... The Stab and Elevator were cut out of thinner Balsa and then 1/16th sheets of balsa top and bottom to include the depth of this captured continuous cloth hinge
Hard to describe and a lot of work back then but his Tail sure was pretty with no obvious hinge
Not sure I will ever try it but Roberts video on Pocket hinges looks pretty trick
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I know for a fact that PW used 1/16" OD aluminum K&S tubing for all the hinges on his 2nd B-17 stunter, with 1/32" wire pin for each moveable surface. I believe he attached the tubing to the surfaces with CA, using micro-balloons and more CA to build up a fillet to strengthen the attachment. I haven't noticed him use this type of hinges since then.
Regardless of surface thickness, it makes tons of sense to simply laminate the hinge slots into the TE/LE as appropriate. If you use the Utah method (CA and strips of silkspan) of installing the pinned hinges, 1/32" sheet core will give a nice pocket. If you can get some 1/20" sheet, a sandwich of two layers with a 1/32" core gives a theoretical total of .131", so you're real close to 1/8" with just a light sanding on both sides. I'd make the "hinge pocket strips" the same width as the hinge tabs or slightly wider...no big deal if a bit wider. D>K Steve
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This is the method I've been using for the last twenty years - NEVER had a failure.
The material is dental floss - Dacron, UV resistant and very strong. Ever try to beak a piece of dental floss?
I've used it on surfaces from 1/16" up to 3/16.
The photos show my Viking setup with well over 1000 flights.
Bob Z.
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CA hinges will work great for this application if you do this.
The material is really tough, so cut two V-notches as shown to reduce the amount of material that has to flex. Sonics' instructions says to wick in the thin CA at the slot in the hinge line, DO NOT do that, that will stiffen the flex area of the hinge. Instead make a pin prick on bottom surface where I show the 4 dots and wick in the CA there. Recently experimented with this on an ARF S1 and it works great. You could also make 2 hinge points out of each one by cutting in half at the wick slot and then still notch that. 1/8" material is plenty strong for each hinge point. The one I notched here, you cant break it by pulling on it..
I intend to try and identify the material they are using here. It's about .011" thick and like I said it's super-tuff. If I can locate some large sheets or rolls I think it can be laminated into balsa structures (same as carbon tow) to add lots of stiffness at minimal weight.
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So just one late(!)comment on
an earlier post expressing doubt about cloth hinges:
I've seen too many violent encounters with terra firma, and in none of them have I ever seen a cloth hinge fail. There were a lot of fancier hinges torn and split out of stabilizers, elevators, and flaps though. I like cloth hinges. Their only drawbacks are (sometimes) hiding them and a bit more control friction.
SK