I am putting a DA 50 on a Dave Patrick Extra 330. The Extra comes with CA hinges but the DA 50 is way more engine than Dave recommends. The DP Edge 540 comes with Robart Hinge Points and it is a similar size to the Extra. I am trying to decide if I should put forth the extra effort to install Robert Hinge Points instead of the CA hinges that came with the kit. I would like responses from those that have experience with this topic.

hi Specman

I dont have exp with this exact plane but I have a 25% Giles that im re-doing for the 2nd time

My rudder now has Robarts installed and my other surfaces have the Radio South CS hinges. I feel these to be safe for anything up to 25% or so. If I had the time I would def go with all Robarts on all the surfaces and finish them with Gorilla Snot glue.

just my thoughts, good luck with your project


matt

I will not use ca hinges on anything bigger than 60 size anymore. They don't seem to hold up to the vibration of the big stuff.

Randy

They only put Ca hinges with arf's or kits above the .60 size so you'll have to buy a replacement plane. Good business practice.

This probably doesn't apply to your plane as I've never flown anything as
large as you have, BUT ::: I have had a Robart hinge point break on the
aileron on one of my pattern ships but have never had a problem with
Radio South ca hinges.
Came loose at the pin. Helluva flutter but no crash.

tommys

I have a DP extra from the 2nd run. I have not flown it yet, been working on it for over a year. Yes, Im a bit slow! I did make a lot of mods, due to remarks here on line and also mfg. mistakes. My DP Extra has Zenoah G-45 on the nose, and I know someone that used to have a Fuji 50 on one that flew just fine. You see, if you want to mount the elevator servos in the tail, you need a heavier engine in the front. I did not want to install pull pull for the elevators. This aircraft has had flutter issues, at least alot of people have complained. There were many reasons discussed, from "twisty" or flimsy ailerons, to needing two servos and the list goes on. Here is my setup:

Robart hinge points for ailerons
Robart hinge points for rudder
B&B 1/4 scale CA hinges for elevators
Hanger nine titanium rod links
Rocket city hardware
Hitec 945 metal gears aileron, elevators, and a Hitec 5645 digital for rudder.

The reason for The CA hinges in the elevators is due to the stab tube limits installation of the robart points. The robart points need to be cut down, at least two of the points. It leaves little hinge in "meat", and no room to add a hinge block. This is why I went with the heavy CA hinge for the elevators


I also modified for Rocket city hardware. You will need to add a hard points on all surfaces on the top if you use Rocket city hardware and run the screw from the top through the bottom. DP has only a hard point installed on the bottom as stock. The rocket city hardware may not be necessary, but I feel better about it. The rudder already has two hardpoints installed, and does not require mod. I also sheeted my ailerons with 1/32 sheeting top and bottom to "stiffen" the ailerons. I have made many mods, some needed and some well I feel better about. Also, I had a warped right panel out of the box. I fixed that problem, and relized one wing was sanded very heavily compared to the other. It was quite thinner than the other panel. It was really weird. Needless to say, I fixed all the problems, (as it still was quicker than trying to get a replacement from DP ha! ha!) which required me to recover the wing panels. Thus the reason I went ahead and added the hinge blocks ect. So it depends on what you want to do. If you use CA hinges, you should probably try the B&B 1/4 scale CA hinges or the Radio South 1/4 scale. Seems like people like those. I know the B&B hinges are very strong and thicker than most I have seen. Its a beautiful plane, and it will fly this spring! Whew hoo!!! Oh yes, be sure to seal the gaps in the surfaces!

I used ca hinges on mine and have had no problems! Although I did add an extra hinge as they recommend. Powered by O.S. 1.60FX, used pull/pull on elev. and rudder 2 servo's in each wing. 12.6 lbs. I have one of the newer releases also, laser cut they were able to shave almost a pound off compared to older model. Don't know exactly how many flights on it but no problems what so ever. I did find that they were a little conservative with c.g, I believe that I'm a little past 6".

I posted a thread on this very subject a while back. There was a poll done and roughly 50% had a failure of some type with CA hinges and 50% didn't. The difference in the post I started centered exactly around the very question you are asking. I have a DA 50 on a Pitts 1/3 scale. I used the stock G.P. hinges that came with the kit. After only four flights two of the three hinges cut clean through on the rudder. I got the plane down with no damage. I had never had a CA hinge fail in the past, so I felt confident in using them. Now the question why did they fail? No binding so let's get this out of the way. I have always doused CA hinges with CA so this may have contributed. It was cold which may have made them brittle. Add to this the vibration form a gasser this size and I think you are setting up a problem to happen. Regardless, a 50% success ration is not a good plan when there are alternatives. Granted this wasn't a scientific poll but........ I replaced all the hinges in the Pitts with Kletts Flexpoint hinges. I used these because there wasn't much wood to bite into, or I would have used Robart Pinned hinges. The Kletts are pretty easy to install.

I continue to use CA hinges but have converted to the blue Radio South hinges and won't ever again use any CA hinges in a 1/4 scale up with a gas engine. Some guys use a crayon on the flex line and maybe not as much CA as I did. Not sure if there is a perfect answer but think too much CA, combined with cold weather and vibration from this engine all caused the failure. Yes it's more difficult to take the time to install them now and even then there isn't a guarantee, but it's easier to do it now then later, especially if you lose an airplane in the process. Now no doubt others will say they have used CA hinges in a gasser and never had a problem. Hey, thats fine. I did have a problem and simply sharing what I learned from the experience. IMHO.

I used DuBro 1/4 scale hinges all around on my DP Extra. I'm completely off CA hinges these days. It is true that the elevator joiner tube can get in the way and you must consider this in your hinge installation.

Good luck.