Hinges?

[ADW 123]

I have been doing more work with hinged control surfaces and was wondering what everyone uses for their hinge material. Keep in mind that the control surfaces are constantly being moved back and forth as they are for U control and R/C. I have used the following-

Cloth- works well as long a you keep glue and dope off of it, but it is a pain to slide the cloth into a hinge slot

clear plasic- works well, easier to slide into the slot, but is even easier to crack if small amounts of dope and glue find their way in

aluminum (can material)- sucessful but had it break due to some glue and or dope

1/64" ply- cracked too easily, very stiff but would work for a heavier duty hinge with a small range of motion

going to try twisty ties soon.. hear those work well too

any others I should consider?

[Phugoid]

Hi Alex,

I don't think that the alumimium would be subject to any effect of glue or dope. What you are seeing is more likely to be "plastic fatigue". What I mean by that is once you subject the hinge material to a stress greater than it's elastic limit (when you bend it), it will deform plastically and more or less "stay put". A number of reversals of this stress (bending the hinge back and forth) will see the material fatgue - and break off.

One way to mitigate this is to make sure the bits of can you are using have smooth edges and no sharp corners. Both act to be areas of stress concentration and will reduce the life of your hinge considerably.

I only use the twisty ties on free flight models, knowing that I will not be constantly making "reversals" so they are fine for that but I think that they would suffer the same fate as the can material.

However one thing that I do, is fully cover and then dope everything BEFORE I fit the hinges, doing this really opens up the use of the best material for the job - the plastic that you mention (as long as you select the right glue I suppose). These materials are ideal as hinges as they are stiff but not too stiff and do not suffer from the fatigue problem as do the metals of the can and wire tie. In fact the use of such "plastic hinges" is very common in many "non critcal applications" from lunch box lids to plastic file holders etc....

Andrew

[Bill Gaylord]

I use the GWS thin white mylar hinge material for all my micro models. From what I hear, the old floppy disks are similar. This GWS material does not suffer from fatigue failure, and can be first inserted and then touched with a drop of thin CA. The thin CA will not make it too stiff. It is nice to fully assemble control surfaces, set the hinge gap, and then glue.
This is the stuff below used in my Guillows 16" Stuka, seen in the rudder and aileron hinging.

[Wildpig]

For my current project, which is my first miniature r/c aircraft, I was going to use fishing line for hinges. I don't think it will fatigue fail any time soon. Bends very easily. Not sure what pound test I have. I think it's 5 lbs. Anyway, the plan is to drill small holes in the balsa that are slightly undersize. Insert the line and secure with CA. Not sure if CA will actually bond but, I will experiment with different adhesives.

[Xanadu]

The ones you are looking for are called CA hinges, and you can buy them at your LHS.

http://www3.towerhobbies.com/cgi-bin/wt ... XK110&P=ML

They last almost forever, stay flexible, and easy to install. You cut a slit in the balsa, slide it in, and then wick thin ca into it. It pentrates though the hinge body and down into the balsa forming a bond.
What I do is cut slots into both the trailing edge, and operating surfaces. Do a test trial fit on all before gluing so you can adjust as required. I then remove the hinge, and poke a t-pin through the centre of it. I leave the pin and reassemble the pieces. The pin acts like a spacer when fitting for gluing.
When I am satisfied with the fit, I remove the t-pins and then wick thin CA onto the hinge making sure it gets to both pieces. Having the space ensures you do not glue the 2 pieces together.

How to video.......http://www.youtube.com/watch?v=QpwEvmhpAjY
Another one with more detail.......http://www.youtube.com/watch?v=skD-nql1 ... re=related

I use these on my small ones, right up to my .60 Nitro planes. No failures ever, work very well, and cheap!

[slopemeno]

Ever tried Silicone, or Goop hinges?

They work well- generally they're used with a 1-sided bevel. Use low tack brown masking tape as a temporary hinge on the side without the bevel, and leave a 1/32nd" gap. Fold the control surface as far as you can to open the bevel up, and use a small syringe to lay a 1/32nd" bead inside the bevel. Use a small popsicle stick to scoop out the excess- you don't need much. Let the surface return to it's neutral position, and let it cure for 48 hours. Carefully peel off the masking tape, and you have a very tough hinged surface.

The silicone you want is 100% silicone, or aquarium grade, *not* GE silicone II. If you decide to try Goop or E-6000, remember that these glues have strong solvents in them that attack plastics or most foams. E-6000 is actually a pretty amazing glue if want to try something that stays really flexible for 10 years or so, even when subjected to direct UV.

While fast planes use the Silicone or Goop hinges the full length of the control surface, with light rubber power or electric you can likely get away with two small spots per control surface.

Before you say that it's too heavy and meant for larger planes, I use this system with Goop adhesive on my Baby Jart, which is a small 36" sloper ( the smaller one in the pic). This little rocket weighs 20 ounces, and has been clocked at 94 mph on radar. The elevator on this plane is only 6" across, and the Goop hinges has held up on several cartwheeled landings.

[BillParker]

1/2A 3/32" Hinge Points (15 pkg.)

Hinge Point Hinges are truly unique. Instead of trying to chisel a slot, as with ordinary hinges, simply drill a hole, add some glue and insert the hinge point. Simple, perfectly straight hinging can be done quickly. The hinges are available in three sizes 3/32", 1/8" & 3/16"

.



http://www.robart.com/products/12a-332-hinge-points-15

or...

what I use:

Mini Hinge measurements: 7/16 (11mm) Wide X 1 1/8 (28mm) Long. Precision molded, inspected and assembled with locked in hinge pin. Flash free, simple to install. Hinges have 6 holes on each side for maximum holding power.

http://shop.dubro.com/products/productd ... commended&


try em, you'll like em...


bp


...

[Mitch]

Bill,

I have not used these yet, but with my last order from SIG, I got these...



A pack of 24 for 3.99. On the back of the pack is 5 easy steps for instillation.

The last sentance says "...the hinges are almost indestructile."

Mitch

[BillParker]

Oh yeah, you'll like those, plenty...

I would like to see a photo of one of em next to a penny for scale... When I looked at the SIG site, all the hinges looked to big for 1/2a planes... I order all my Butyrate directly from SIG, so it'd be kewl to add hinges to my order...

thanx!

bp

[Mitch]

Bill,

They are 1 inch x 3/4 inch, I plan to use for Spirit of Saint Lewis. Basically you cut a slot, insert the hinges, add a drop of CA glue on hinge and capillary action wicks it into the slot... your done! These feel like a plastic cloth and can easily be cut smaller.



Mitch

[Xanadu]

Yup, those are the CA hinges use by lots of folks. Thye work great and are easy to use.