MJD

My Feedback: (1)

That's the theory, but if it delaminates then you are back to square one immediately. If you have enough surface area and modest adhesion I think you're probably better off than sticky hinges that threaten to delaminate and let the surface go for a flight on its own.

I've been thinking about this, and it occurs to me that the big aerodynamic watchword for good hinging - a tight hinge line - is probably the worst thing we can do for these hinges. The tighter the hingeline, the tighter the radius the hinge material is forced to assume per degree of deflection. This logically means that the fatigue rate goes up accordingly, and the likelihood of yielding the material at higher deflection angles increases greatly. So it seems to me the right thing to do is provide some form of relief for the CA hinges, either in the form of a controlled hinge gap and post-sealing, or with a small relief groove along the TE and the LE of the surface, or something of that nature.

Naturally none of this applies to properly installed "real" pin hinges. But they are a pain, aren't they?

MJD

combatpigg

My Feedback: (3)

I agree that focusing the stress on the plastic in a tight gap will accelerate fatigue. The trouble with too much gap is it gives the hinge a chance to develope 2 hinge points and now you have a sloppy, floppy, linkage. The first Demon I built developed this problem and I had to re-do the flaps with real hinges. I've used EZ hinges by the hundreds on dozens of models and they've worked 99.9% of the time.....but there's been a couple of times things didn't work out "perfectly", I'll say.

Installing real hinges can be a pain. I haven't bought the electric hinge slotter. I use the pickle fork tool. The key is wood selection! I don't use anything denser than medium balsa as a rule, and the pickle fork works very slick. If I run into a real tough spot, a Dremel cutoff wheel makes a decent starter slot.

MJD

My Feedback: (1)

I bought a Dremel router table ages ago, and with a slotting blade you can do wonders. Trick is to remember to slot the wood before installing it.. I've failed on that account a number of times. Need a sign on the wall.

MJD

mk1spitfire

ive never heard of delaminated fluffy fuzzy hinges before!

I assume,(bad to assume) the thin cyano would penatrate the light fibers and stick also to the surface of the plastic coated hinge of which the fibres are allready stuck too.

Some kits say to leave gap and check up and travel when you move the hinge up and down.

Previously said, hinge is put under stress if you dont. But then you are damed for leaving an unprofessional drag gap!

Is taping over the gap with a clear tape the answer for support or ironing the main body film over the elevons too, in one go?

MJD

My Feedback: (1)

Depends what plastic the substrate material is though - some materials have absolutely no surface energy and CA will barely stick to them. Typical of this universe, the tougher the material often the worse this problem.

MJD

mk1spitfire

On weston uk tigershark they use a fibre based iron on advesive film covering called soletex, right along the length of the hinge line, which sticks to delta wing and elevon, top and bottom.
The hinge is made by sowing two identical lengths of solatex down the middle leaving about 1'' either side of seam,sticky side to sticky side, kind of like a cross when view from the end and seperated.
The shiny profilm is added on top after, so the hinge is covered completley and further fuel proofed, allthough the evil nitro does have its ways of seeping in and lifting the solatex covering, because the hot exhaust gases location of tuned pipe heats the top covering on that model, if your not careful.

combatpigg

My Feedback: (3)

For years I've hinged the control surfaces where ever possible before covering, then cover the whole works right across the hinge gap in one fell swoop. You have to use very low heat until the film has been nailed down completely, then back track with the iron on a higher heat. Doing it this way takes practice, but I like it because it's functional.
I would iron on the Solartex hinge first, then monokote right over it, if bubbling isn't a problem.

mk1spitfire

your letting your anti drag secrets out now cp.

daisy shoot

I've never owned a model long enough to wear out ca hinges....I torture balsa

Mike Connor

My Feedback: (5)

A lot of these guys do but wont admit it.

Mike Connor

My Feedback: (5)

You are right, according to the RCU "how to" article I posted earlier, that it seems no one has read.
They explain how to get the perfect gap. That ok though, reinvent the wheel.

mike31

My Feedback: (67)

DuBro pinned hinges have been around for a long time. Ever wonder why?

mike31

My Feedback: (67)

Iron on gapless hinges work every time. Apply covering over the top.

combatpigg

My Feedback: (3)

I read the article and it was well presented, but he lost my attention when he said to hit each hinge with 4 or 5 drops of CA.

This is the most fundamental error. It caused my very first CA hinge failure. The hinges turned to brittle glass because of the excess glue.

summerwind

[quote]ORIGINAL: combatpigg


Zactly............the ones i just pulled out ranged from still flexable to crumbly at best.

waiting for the Radio South CA hinges to try.

petec

My Feedback: (58)

They sure do. I tried iron on hinging and even did a top hinge using the actual covering on a pattern plane (worked great except for a bit of aileron diferential) and I keep coming back to the Radio South hinges.

My newest toys are Q500 ships, one with a Nelson, one with a Jett and one with a TT Pro 40 and I'm going to try kevlar hinging buried between the core and the skin.

summerwind

LOL...i work with the new BREED of what they call themselves as "Carpenters" (more like Monkey see Monkey do)............. have talent, just lack of good training.

diggs_74

I've not had any issues with CA hinges but I too don't usually have a plane around for long.. The process I do is to first make at crayon mark at the pivot point, on both sides.. This keeps the hinge from absorbing the CA and getting brittle.. As far as the gap goes, I always used the T-pin thickness.. I've done this on speed planes and 3D planes alike.. So far, no failures..

Gooseman240

OOooOOOooOOO!!! NASA music on the flutter test video, so spacy

You should see the one on the A380, just about ripped the entire belly pan off.


So, I test balsa wood too, I don't think my planes will see enough use to cause the fabric to separte like you folks have mentioned [X(]

Iflyglow

My Feedback: (79)

IF you take a hinge from sig or great planes, you can pull the hinge apart with your bare hands if you try. The CA does not bond to the plastic whatsoever. It bonds to the covering on the hinge. The hinge will come out like a shiny piece of plastic. The only way I have been able to break a Radio south hinge is with a Vise grip. I have done many destruvtive tests on CA hinge sampes. If you put a nick in the side of any of them, you can tear them exttremely easy with your bare hands.
I also use as many drops as it takes untill they quit soaking it up (useally about 4), and then quickly dab it with a corner of paper towel to soak any up that does soak in. You have to work fast, but I have never ever had a Hinge fail.

Gooseman240

IF you take a hinge from sig or great planes, you can pull the hinge apart with your bare hands if you try. The CA does not bond to the plastic whatsoever. It bonds to the covering on the hinge. The hinge will come out like a shiny piece of plastic. The only way I have been able to break a Radio south hinge is with a Vise grip. I have done many destruvtive tests on CA hinge sampes. If you put a nick in the side of any of them, you can tear them exttremely easy with your bare hands.
I also use as many drops as it takes untill they quit soaking it up (useally about 4), and then quickly dab it with a corner of paper towel to soak any up that does soak in. You have to work fast, but I have never ever had a Hinge fail.
[/quote]


Hey Motorman!!

You must have looked at my photo's and saw that I have a SS 40 MKII, thanks for pointing out how you figured it out. So all in all, just rip out the old hinges and put the new one's in.

Do you have to use the slot tool to clean the the slot out on the wings, or make new ones?

Mike Connor

My Feedback: (5)

Yep, that is what I said in my first post in this thread, too much CA.

summerwind

looked at the GP Skybolt assembly manual...................."put 6 drops of CA on the hinge, then flip wing over and put 6 drops of CA on the other side"................duh, way too much.
the hinges came out along with sliver of wood, but on most, the hinge plastic seperated and you could see exactly what Motorman was talking about. makes me wonder how the fiber was bonded to the mylar.

like has been mentioned, 3-4 drops of CA is more than enough.

summerwind

got the R South hinges today...........look good and strong.
question, on the GP Patriot plans, they show how many and what locations to put the hinges in, and those are the wider GP hinges........with these being a bit narrower, will i be alright using the same amount?

such as the elevators, there are 2 per..........

DougV

Hi Mike,

On my Patriot I'm using 3 CA hinges on each elevator half and 4 on each aileron half, never had an issue with this jet or with any of the planes I ever have/had using GP CA Hinges.

Regards,
Doug.