I installed CA hinges on the elevator of my LT-40. The elevator seems to "snap" between the up and down position, that is there is not a smooth transition as the elevator passes over center. The more I work the hinge, the smoother it gets, but still not perfectly smooth. This also appears to create a small flex in the stabilizer at the same time.

Did I get the hinges misaligned or could this result from a warped elevator or both? And should I pull it apart and try to fix it or will this be ok in flight? I dread trying to pull apart CA hinges.

V- Just use your exacto knife, and cut the old hinges off flush on both sides. Re- install new ones beside them, and make sure everything lines up good before you put the glue in. Don't try to fly it like that.
A pack of Sig EZ hinges cost about 2.29 at the hobby shop.

Jetts

I'm with ya. I may have done the same with my ailerons. I'm interested in seeing who chimes in and their responses. Good luck.

Jetts, would a slot machince be needed or can an exacto #11 do the trick?

The problem is, that i believe that the elevator is a bit warped and that may be the main contributor to the problem. Prior to installation I tried and managed to get most of the warp out, but there still remains a slight bend. I may have to replace the entire elevator

Cruzomatic, either will work, but personally, I'd go with the exacto. better fit, just be sure to make the slots as flat as possible.


V-while your at the Hobby shop getting hinges, take the elevator with you, and for another 2 bucks, you can get a piece if balsa to replace the elevator. I built a Pt 40 for my Dad, and the elevator was slightly warped, not as bad as you are saying though. After 5-6 flights the hinges started to give out, and I ended up replacing the whole works.

Also, when you install the new hinges, put them all in, push the pieces together, move the elevator up or down about 45 degrees, hold there, and apply your thin CA. this will help keep everything square.


Jetts

The elevator is fine with a warp in it. Your hinges will take care of the problem.

Your problem is that your hinge slots are crooked. This causes the stab to flex when you move your surfaces.

Get a slot cutting jig, they really help eliminate this problem. I've heard that the slot machine is very nice as well, but it is overkill for solving this problem.

Slot cutting jig? Sorry, but don't know what that is? Where can you get one?

At your LHS (Local Hobby Shop)

Here is what I have...
http://www.hobbiesr.com/dub/dub-fiel...ols/dub660.htm

V

your plane will probly fly like it is , but if you choose to leave the elevator as it is , be sure and check those hinges often , failure will not result in anything good , if you know what I mean .


Highlander

I think at this point I will try replacing the hinges. I would hate to see the elevator leave the plane during flight, or in the alternative, lock in the full up or down position. In either case, it would not be pretty.

Thanks for your input. I will let you know how it turns out.

V

Good decision!!!

there are some good threads on replacement of ca hinges.

tips and techniques forum.

let us know how things go,

Highlander

I replaced the hinges last night and problem solved. It was much easier than I thought it would be. Just cut off the old hinges, trimmed them flush and installed new hinges adjacent to the old. Worked like a charm. Upon disassembly, I found that one hinge had be installed a bit out of alignment causing it to flex.

Just a few observations. As this is but the first of what I hope to be many planes, I bought the GP hinge slotting tool. Man did this make the job easier. Almost made me want to recut all the hinge slots. The GP and guide cut dead on straight slots. Also, I used GP CA hinges instead of SIG easy hinges. The Gp hinges have the corners cut which really make installing the hinges much easier.

Thanks for all the help and suggestions, now once I get the radio will be ready to fly. Wife bought me a Futaba 6XA for my 40th birthday which is 6 days from now. I begged but she won't give it to me early.

Victor

Congrats on the hinge fix. As for the radio, find it, use it and then rewrap it.

She'll never know.

Glad to hear that everything went good and turned out right,

try hanging the plane from the cieling in the living room , maybe she will give up the radio

but really just sounds like she is having some fun with you, and your new hobby, and believe me thats a good thing much better than the alternative .

Highlander

And, sometimes, a solid balsa control surface that has a slight bow and is covered with a "monokote" film can be straightened by applying a covering iron to the convex surface to re-shrink the covering. Care needs to be used since the film can still de-gas and bubble (if it does, reduce the heat, ***** the bubble with a pin and work it out with the iron).

At any rate, a control surface that catches or snaps needs to be corrected since that surface will not consistently re-center. As we found on this plane, the hinges are likely mis-aligned and can be easily replaced.

I did remove most of the warp by heat shrinking the monokote. It took most but not all of the warp out. The elevator wsa my first covering attempt and ended up with a few bubbles that I took out with a pin. The woodpecker and patience made the rest of the job turn out not so bad for a first attempt. Am looking forward to starting ym next project, a Tiger .60 and working with my son to build his Something extra.

Highlander:

Don't think hanging the plane from the living room ceiling is a good idea. Out-of-sight-out-of-mind. It is much better that she not know what I have . While we are each generous to the other, I don't look in her jewelry box, she dosn't look in my workshop.

V

Guess you will just have to wait till your birthday then ,

really I admire the respect , was just joking ,

much the same way my house works .


Highlander

V

I almost forgot , when you and your son finish the Something Extra would you be interested in selling the plans?

I was given 2 of the arf versions that have been crashed , I want to fix them ,the plans would come in handy .

the wings on both are intact as are the tail sections but both have been damaged back to the radio compartment .


just about Identical damage .both from the same person.


Highlander

If I sell the plans I would be out of luck if/when the Somethng extra goes down. As a Patent Attorney, I am kinda sensitive about the whole copyright issue and would not feel right selling you a copy and retaining one for myself, sorry. I am sure SIG would be more than willing to either provide you with plans or, alteratively sell you a set.

Best of luck.

Hmmmm, patent att.

Ok well , I will continue looking . Im ay be able to get one thru sig ,but probly cost me 80 dollars for the kit .

I understand your position , having a file full of non discloser forms and date of conception letters to myself . even some dated knapkins from coffee shops that I frequent. LOL

Highlander

SIG should be willing to sell you just the plans. Explain your position and ask, at worst they can say no.

As for the napkins, save them they can be as good as any legal document. I had a situation where plans drawn out on a chinesee resturant placemat saved my a client thousands.