RE: CA Hinges in gassers - Hinge failures
 

rfw1953,
Are you using the Great Planes hinge slotting tool for your large Du-Bro hinges? They have come out with some blades that are for thick nylon hinges (I think they may have three different thicknesses, but I'm not sure). I don't know if these blades are the correct thickness for the hinges you are using, but it sure would be alot easier than the old knife blade method! It's kind of a pain to keep changing the blades back and forth for each project. If you do enough hinging, it might be worth buying a couple slotters to avoid the hassel.

I used the nylon pinned hinges on a smaller plane, and secured them with epoxy (after roughing up the surfaces). They are holding well after four years. On a high stress plane, it might be worth using epoxy then pinning through the bottom of the surface with some tooth picks. I read a good tip to cover the tooth pick holes by punching out a little circle of Monokote with a paper hole puncher, then iron on w/ a trim tool.

I think I will also use the Du-Bro 1/4 scale pinned hinges on my Pitts.

Pilgrim

RE: CA Hinges in gassers - Hinge failures
 

I have used C/A Hinges for years with good results. The question is how long they last. I have a Four Star 120 that I've replaced the in board hinge a couple of times. My Forty size speedsters don't outlast the hinge. Due to seeing the hinges crack and break on my Four Star. I put 1/4 scale Du Bros in my 1/4 scale Giles 202. I pinned them with straigth pins. My F-16 has CA Hinges but the gaps are sealed with Monocote which adds strenth. I don't think I would use them on a Plane I expect to last a long time!

RE: CA Hinges in gassers - Hinge failures
 

I had the elevator hinges fail on my Kyosho Me-109 fortunately it is a split elevator with dual push rods or it would have bought the farm .. this was the 4th flight.

Then a month later the aileron hinges failed on one aileron.. the hinges are the CA type.. they split clean like I used an exacto knife ..

This hasnt happened on any of my other planes yet.. but it sure makes me wary of using em, they are easy to use.. and cheap..

After the 2nd failure I use Robart hinge points

The TF P-51 arf I am putting together uses hinge points for the flaps and ailerons but CA hinges for the rudder and elevator .. makes me real nervous to use CA hinges on a large airplane

RE: CA Hinges in gassers - Hinge failures
 

I guess I've been fortunate! 90% of my planes have the CA hinges including my 31% Edge w/3W75. My first edge crashed but none of the flight controls came off. I've had 0 failures other than crash damage. But... I very seldom use the kit hinges. I usually use the Sonic-Tronic hinges. 2 drops on one side and then when it dries, 2 drops on the other. I also seal at least 1 side with covering(my edge is sealed on both sides!). My Cristian Eagle has the same hinges installed. Now on the 31% I have 11 hinges on each aileron. I usually double the hinges on large flight controls. I probably would not use CA hinges on anything larger than my 31%.
You must also ensure that you have at least a 1/32nd gap between the flight surfaces. If there is no gap then this puts undue stress on the hinge. the 1/32nd gap means that you will always have to seal the hinge line with covering(or tape!).

RE: CA Hinges in gassers - Hinge failures
 

Hey Guy's
I thought I'd chime in on this subject.
I too have seen failures on the CA hinges and have chose not to use them.
I have been using Du-bro or Klett large scale size hinges.
I don't use the cotter pins or the pins that are flattend to retain them.
I remove these and use .047 music wire or the appropriate diameter as a continuous hinge pin thru all the hinges at once.
By bending the wire in a J configuration at the outboard end of the control surface
you can just press it in to the outside edge of the wing, horizontal or vertical and apply a
small drop of thin CA to retain it.
The nice thing with this set up, if by chance you do have a failure you can just pull the wire
out and the leading edge of the control surface and the trailing edge of the wing, vertical stab or horizontal is exposed and a lot easier to take the broken part out.
Good luck.
Bob Hines

RE: CA Hinges in gassers - Hinge failures
 

Really appreciate all the responses on this subject. Been most helpful. Don't flame me for asking this one, but thought I would inquire before trying this. The problem I see with the Robart hinge points is that they are too long and concerned that the ribs won't bite into the wood enough to get a secured fit on the Pitts elevators and ailerons. The size is also pretty wide and the flex point of the hinge appears so large that it will form a huge gap between the two surfaces.

G.P. Makes small hinges points that appear to be the perfect length. My concern is about how strong they are. I could easily mount 5 or maybe 6 of these in each movable surface which combined I would think would provide the strength needed... Yes? No? The reason for asking is because of the length. It appears that I can drill the hole without going through the wood to get a good snug fit and to keep the glue from seeping out the back side. Have any of you used these? Here is a picture and the tech notice.

Tech Notice:The Pivot point hinges are used to connect control surfaces to the airplane,
such as the trailing edge and the leading edge of control surfaces.


FEATURES: The pivot point hinge has four interlocking "fingers" at the joint
instead of the usual three. This ensures an extra strong hip joint.
Locking fingers increase strength and durability.

COMMENTS: Customer will need to purchase the epoxy separately
Hinges look similar to two christmas trees joined at the bottom.

SPECS: Overall length: 1-1/4"

RE: CA Hinges in gassers - Hinge failures
 

Roger,
The Robart Hinge Points need to be countersunk into the control surfaces to keep the hinge joint snug.

The mini hinge points you posted would probably work as long as you use enough of them. Same principle as the larger ones, need to be countersunk into the surfaces.

I don't like putting so many hinges in, so I think I will opt for the 1/4 scale hinges and just use the same amount as called for in the plans.

Pilgrim

RE: CA Hinges in gassers - Hinge failures
 

Well, just replace them with Robarts ! Here's how : http://www.rcuniverse.com/forum/m_13...tm.htm#1338490

RE: CA Hinges in gassers - Hinge failures
 

Not all CA hinges are created equal...... The typical hinge in an arf is just that typical. Try the blue radio south 1/4 scale ca hinges. I have had them for over a year in my bme powered gp patty. I have had 2 fail on the rudder after a year but I dont think that was there fault. I use the rudder hard in low high alpha KE and figure 8's and time and vibration took it's toll. I have seen robart pins pull clean out of a 35% gasser on the third flight on the rudder. any hinge can have a failure. Just use a quality ca hinge. Of course there is a limit to a ca hinge IMO, I would not use one in anything over 27%. Ohio superstar also makes a giant scale ca hinge (10-20 lbs) I have used them on several fun flys and have never had a failure with them flying them very hard

RE: CA Hinges in gassers - Hinge failures
 

well, I did a little experiment yesterday with a 3/4 " piece of balsa and a robart 1/4 scale hinge point as well as gorilla glue. I drilled a hole with a 1/8" drill bit and then applied some water inside the hole with a toothpick. I then applied the glue spreading it inside with the toothpick and then slowly inserted the hinge point through the balsa. Like expected, the hinge point came out on the other side pushing a little glue out. I left it alone overnight and came back this morning to see how it turned out. It worked great, and I was not able to pull it out with a pair of pliers. I would have torn up the wood before pulling the hinge point out. The gorilla glue expanded nicely and due to this created sort of a plug behind the balsa. It did not expend to the front. Just perfect. The hinge moved freely (I did apply a drop of oil to the center of hinge point prior to gluing in) without any problem. This gorilla glue is some strong stuff. Might even be stronger then epoxy for this application.
After this test I am confident that it will work fine and I will use this technique on all surfaces. Will also go ahead and cut out and replace the aileron CA hinges with hinge points.

RE: CA Hinges in gassers - Hinge failures
 

I have tried the same experiment but w/ epoxy and Robart hinge pts. I tried them w/ a mock up trailing edge of 3/8" so the point would stick way out the back side w/ similar results. I make sure there is epoxy on the hinge pt and in the hole. The barbs on the hinge pt help protect the glue from all being pushed out the back when it is inserted. Also, I stand the surface vertically, so any glue forced out the back will flow back towards the hole.

RE: CA Hinges in gassers - Hinge failures
 

Thanks for the many suggestions and very helpful ideas on both different kinds of hinges and how to install pinned hinges and Robart hinge points. I purchased these and also the Kletts Flexpoint hinges and did a few experiments myself. I just couldn't get past the reality that on the Pitts and most likely the CE, the trailing/leading edge of the fixed surfaces and the ailerons, elevators and rudder just don't have the wood to get a good bite. Also, the size of the Robart hinge points and the lack of rib support lost after countersinking to eliminate the gap just seemed to be another area of concern. Countersinking to eliminate the gap would cause the hinge point to be so deep in what little wood you have that the ribs on the hinge point would provide no added support regardless of the glue used. Even with Gorilla glue it just seems that you have to have wood and rib contact for any kind of glue to add support. The concept of Gorilla glue forming a plug on the backside made perfectly good sense and from the experiment reports this does work as suggested. Conversely, you still need wood to bite into. One option would be to add a hard point behind the trailing/leading edge for added support, but this would require cutting into the covering, which I would prefer to avoid if possible.

So, My good friend Chuck and I looked again at the idea of using Kletts Flexpoints. We used 6 on the rudder and 5 each on all movable surfaces. I didn't want to experiment on this new airplane and so Chuck volunteered to help again after he had already helped me by installing the flexpoints on the rudder. Note: as we removed the recently installed stock G.P. CA hinges we noticed how a few of the hinges on the ailerons and elevators had also broken, but you couldn't tell because at least two each were still holding the moveable surfaces in place. Even when I cut into the others we were amazed at how easily they came apart. Meaning, they were barely holding together. This was a problem waiting to happen had we not replaced all CA hinges.

Several of you mentioned there is a difference in various brands of CA hinges. These had the fuzzy felt fabric on what appears to be a plastic type core. Very brittle and broke in two very easily. Since this was such a new model it's hard to believe that UV rays from the sun or exhaust vapor had anything to do with the failures. We can only surmise that vibration from a large gas engine was the culprit. That and possibly too much CA. Chuck has much more experience than I. Over 30+ years. I have four years. We both have never had a CA hinge of any type fail before and we both douse CA hinges in CA glue. Speaking for myself only, it just seems that more CA is better than not enough. I'm not talking about so much CA that its running all over the place, but certainly enough to make sure the wicking effect gets plenty of CA into the wood. Then again, maybe this causes the hinge to become too brittle. Add vibration from a gas engine and, SNAP they go.............

Installing the Flexpoints in all movable surfaces took about five hours. We shot the bull a good bit so it can be done faster. The weather in Al. was terrible today so this was the perfect time for this project. Two friends solving an RC problem together. It sure helps to have someone holding on to things when using a dremal saw bit to make the cuts so the flexpoints fit snug to avoid any gaps. Using so many flexpoint hinges will add additional strength, but this also makes the installation more challenging, especially when cutting into previously hardened CA hinge slots, which is hard to avoid. Getting the alignment perfect is key to installing multiple flexpoints to avoid binding. Chuck did this perfectly. We used think Zap CA for the flexpoints. This was tested in an elevator I had from Pitts-1 so this was as real as you can get for testing without flying. We removed the covering so we could see behind the leading edge of the test elevator. I drilled all the way through the test elevator wood and then used thick Zap CA to see if there would be any problem from the glue being pushed out the backside of the hole. I had done this test a few days earlier so the CA had plenty of time to cure. We couldn't pull the flexpoint lose with pliers so we felt confident this was a strong solution. Next thing to do is get the bird back in the air to see how these hold up. One thing for sure. While this may not be as strong as a Robart hinge point with a metal pin in the middle, we feel the snug fit with the wood available and the number of Flexpoint hinges used will certainly be much stronger than using any CA hinge.

I think the Robart Hinge Points would be a great solution when you have plenty of wood to bite into. If not, using Kletts Flexpoints and more of them seems to be a good alternative.

RE: CA Hinges in gassers - Hinge failures
 

from what i have read here i will never use a ca type hinge.cost of ca hinge vs cost of pinned hinge< cost of total plane engine and radio.how lomg a ca hinge last is a moot point in referencing murphys law the hinge will only last till the worst possible momment for it to break.i have a 33 year old falcon 56 that gas dubro pinned hinges in all surfaces and have not ever failed or replaced,same with my 30 year old stafford p-39.
i have a 29 year old skyglass cutlass that also has not had any problems with engines.i have used pinned hinges in a robinhood 80 with a maloney 125 for 12 years and no problems.they may take a bit longer to install properly but i believe the longetivity is worth the effort.

RE: CA Hinges in gassers - Hinge failures
 

There is a poll in the ARF category on this subject that generalizes the question about the use of CA hinges. I think this poll is very misleading. This thread was very specific about the use of CA hinges in larger gas powered airplanes. Read not only my comments from this experience but those from others to make your own decision. [b]IMHO CA hinges are not a good alternative for larger gas powered models.

RE: CA Hinges in gassers - Hinge failures
 

I have use CA higes on up to 80" airplanes and have never had a problem. (these airplanes are abused!!!!!!!!!!!!)

I take a crayon and draw a centerline on all of the hinges, both sides, then stick them in the center with a T-Pin for installing. Once installed, I cover the gap with monocoate on the bottom.

The wax from the crayon keeps CA out of the hinge point and and leaves it very flexible.

I do minimal hinging, 3 for rudder, 3 per elevator and 6 for aileron. I turn the hinge sideways for the point at the tip of the elevator and aileron instead of adding a extra hinge at these stress points. It cuts down on rotational weight and helps to prevent flutter.

RE: CA Hinges in gassers - Hinge failures
 

Darrinc,

I certainly can't knock your success on the topic. I too had felt confident until mine failed. I'm still not certain as to why they did, but feel possibly too much CA combined with cold temp. and the vibration from a 50 CC gasser all created a volatile combination for failure. The only point I have been trying to make in this thread and concerning the poll is that several people have experienced failures, not only in larger gas powered models but in smaller ones as well. In the poll 67 of 136 votes have had some kind of CA hinge failure. 69 have never had a problem. This is basically like flipping the coin with a near 50/50 chance of failure or success. I don't like the odds regardless of how you install them. If I thought my engine , servos, Rx. or Tx. would work only 50% of the time I would find an alternative. I wonder what the response to the poll would have been had the topic been limited to 1/4 scale airplanes and up with gas engines? I would venture to say the vast majority would not use CA hinges of any type.

In the end, you and I are both confident we have a solution which is really what it's all about. I just hope we are both right and the odds of success improve with each solution.