VF84sluggo

My Feedback: (55)

I need to repair the 'live hinge' for the flap on my SM L-39. Any suggestions on where to get Kevlar tape for the repair? Any suggestions on the best way to install the tape?

Thanks!

f106jax

My Feedback: (16)

Hey Randy,

The live hinge on my SM F-4 right flap tore at First in Flight this year. After researching several threads on RCU about live hinge repair, I ended up installing Robart hinge points. I know that this doesn't answer your question, but I throw it out there as an alternative. The change was easy and I never have to worry about a live hinge tearing again.

It was good meeting you at Super Jets South.

wojtek

My Feedback: (73)

I agree with what Mike said .. with a flap where the hinge pivot is usually on the lower skin of the wing and not visible, a Hinge point becomes a lot cleaner or a repair ...

I personally miss ofset hinge-point type of surface mounting ... its more reliable, and is actually more scale. Whats marketed to consumers as easier and more reliable for them to install, is juts something just cheaper for the manufacturer to produce ... [&o] I dont mind it on a sport Jet, but on Scale planes id rather not have live hinging myself ..


~V~

RCISFUN

My Feedback: (44)

+3
When I was rebuilding a Reaction wreck that I picked up, one of the live hinges was torn, Robart to the rescue!

VF84sluggo

My Feedback: (55)

Ok, I'll consider Robart. Is there a particular Robart hinge part # that y'all would recommend?

Woj, could you expound on this "I personally miss ofset hinge-point type of surface mounting"? I'm not sure what you mean.

Thanks,

Randy

JRSmith

My Feedback: (47)

Randy,

If you do need some kevlar tape for the repair if you decide to go that route, I have plenty of kevlar tape here at the house. Take care.

Jason

VF84sluggo

My Feedback: (55)

Great Jason, thanks! I probably shoud have you take a look at the wing and see what you think.

Randy

rhklenke

My Feedback: (24)

I have used a piece of the the Radio South 1" X 36" mylar hinge material to re-install a live-hinged aileron that got ripped off my GJC F4D in an off field landing. It worked well and was easier to install than replacing the live hinge with Robart hinge points. I would probably not use it on a surface for a large aircraft, but for an L-39 flap, I think it would do fine.

The problem with replacing the original kevlar hinge with another strip of kevlar on the back side of the surface is getting it to attach to the back of the surface all the way up to the edge, but not having any adhesive in the very narrow area where you want the hinge to flex. Using a mylar hinge, you don't have that problem as the mylar hinge material doesn't absorb adhesive.

You can find it here:

http://www.radiosouthrc.com/closeup....d=806&offset=0

Bob

Wclays

My Feedback: (85)

A live hinge is acutally peel ply sandwiched between Fiberglass. (This the only way I have seen a live hinge made and peel ply is what I use on layups) Since it is done on the orginal layup I do not know really anyway of repairing it.

I would install blocks and use Robart hinges. I would trust this type of repair.

Hope this helps

Clay

TheTick

I had a live hinged flap come off of one of my sailplanes. I used a bead of silicone glue and it held just fine at very high speeds. It makes for a very clean and super solid repair. Would this be an option for your l-39?

DelGatoGrande

My Feedback: (23)

Randy

i hada etter look on the L39 flaps .The robart hinges wont work.They r too short.

The support woods of each side are just too far apart from the hinge line so the robart hinge will be exposed.For a flap this size its not good.

Just repair the live hinge with kevlar cloth.sand down,glue it..and brake free the hinge line.

IMHO stay away from peelply.once the epoxy will cure like a glass,its will cut off after 5 or 50 hinge moves.It WILL fail.

Just take a small cloth of peel ply and kevlar cloth.Get a good pair of scissors and try cut them...then you will know what i mean..


....build to last

MaJ. Woody

My Feedback: (28)

Mike,
Did you replace all the hinges for every surface with hinge points or just the one for your right flap?
Thanks!

JRSmith

My Feedback: (47)

I can take a look, no problem. Just give me a call. Take it easy.

Jason

Nhalyn

You can have a good description on this web page on how to add an hinge to a live-hinged wing.

This is for a Krill IMAC model, but it's the same for our jets...

Please scrool down the page : [link]http://krill-model.com/download/manualyak55m_33/language/Tuning.htm[/link]

f106jax

My Feedback: (16)

Dom,

I put Robart hinge points on both flaps. The ailerons I left live hinged.

MaJ. Woody

My Feedback: (28)

Thanks Mike.