Robart hinge pockets
 

Hey guys im building a 35% cap and im having problems with my hings pockets ive never used them before just the hinges i have multiple wing and ailerons to be interchanged with this plane and every time i try to install the pocket dry into both the wing and the aileron and then put the hinge into them my hinge gap is like 1/2 inch please give me some tips or trick im missing i thought of enlarging the hole but then i cannont get to the set screw??? please help>>>>

RE: Robart hinge pockets
 

Just my 2 cents worth and I'll give you change if I charged to much.

I just switched to the Robart hinges. I'll never go back the the flat pinned hinges I had used. I did look at the hinge pockets and the first question that came to mind was WHY. It is an additional level of complexity, read another failure point. Are you really going to switch ailerons on a regular basis?? If so, you don't want soft plastic locked with a set screw in a soft plastic pocket, but at least an aluminum but more likely a steel hinge setup. Plastic doesn't take kindly to repeated screw clamps. Aluminum is a little more forgiving, but to have someting you will change regularry, you need hardened steel.

As for the holes being off, either in alignment or depth, it means you have to have a more precession setup to install them, and make the changes in the air frame to accomidate them. IE a hole in the surface to get to the set screw.

I guess it all comes back to my first question, WHY?

Don

RE: Robart hinge pockets
 

As for the why, it seems that hinge failures seem to happen at the hinge pin or knuckle. Drilling out what's left isn't easy. Popping out a couple of set screws and replacing a hinge seems superior and can be done in minutes instead of hours. This assuming the weakest link is still the pin/knuckle and not the set screw.

I too have questions about installation. I have models with these types of hinges, but I've never been faced with drilling for the hinges. Is it done with a standard drill bit or is there some sort of special tapered tool or jig to do this?

RE: Robart hinge pockets
 

I ask the question of the group on what methods were used to cut the seats. I tried a few of them, but the small file seemed to work the best. I use a little jewelers rasp for wax vs one of the metal files. It is more agresive on the balssa. I use a brad point drill with the drill guide to drill the holes. I've had a couple drift just a bit and to get them back in line, I use a Roto Zip 1/8" wood bit in a pin vise and use it as a broach to nudge the hole back in place. The key is to keep the hole as small as possible, but you have to put a flat taper in to get the hinge deep enough. It all looked quite intimindating at first, but once I got the work in my head, it goes quite fast. I looked at using a cone shapped bur to cut in the taper, but that cuts an oversize hole. The small barrette file is the best way to go. It gives the best seat, support all the way to the hinge line.

As for drilling out a broken hinge, I would be more inclined to cut them flush and move the hinge a 1/4" away. New wood, and with the exception of the little notch in the LE, it would be good as new. I've used this method with the flat pinned hinges, but there you usually have to move them an inch or more to get fresh wood.

Don

RE: Robart hinge pockets
 

it seams as if the pocket would have to be recessed in the leading edge? i tried one last night and to ge thte hinge point to line up anywhere close you have to recess them and then what about the set screw do you drill an acess hole? i love the hinges and drilling them are a pain in the rump ive used just the hinges before and if your doin alot of 3d work as I am the multiple wing and aileron setup would rock if I ever had to use them. There is a Jig according to robarts website i measured out all of mine before hand both wing and aileron i also have multiple rudders and elevator halfs. well any input on recessing the pocket?

RE: Robart hinge pockets
 

I use nothing but Robart hinges but I've never used the pockets. But I think the idea with the pockets is to put a pocket in one surface and glue the hinge into one surface. Only one pocket per hinge. You might see if that lets you get a smaller gap.

Dave

RE: Robart hinge pockets
 

Unless you are doing some scale mountings, you will set the hinge point into the wing so the center line of the hinge pin is just a couple thousandths off the TE of the wing. Then you seat the hinge point in to the aileron so the gap between the LE of the aileron and the TE of the wing is as close to zero as you can get. This will always require that the hinge seat in the aileron will be deaper. You will have to cut a notch in the LE of the aileron to allow for movement. I use a 1/4" bur in my Fordom Flex shaft and cut it deep enough so the hing can swing 90 degree either way from straiht forward. The pocket in the TE of the wing should also allow the hinge point to swing 90 degrees in either direction. This applies no mater wheather you are using the pockets or not. It is the geometry of the hinge. The pockets complicate the setup. In my opinion, they don't offer a benifet to ofset the complacation, so why bother.

My suggestion is to set up you first plane with the hinge points without pockets and then see if you really need the pockets on your next one. One step at a time.

Don

RE: Robart hinge pockets
 

My questions would be why install hinges that have a record of failing and so therefore have prompted a "fix-it" produce by the manufacturer?

http://www.robart.com/how_to/hinge_points.aspx

I'm sure that Robart hinges are great from some uses. However, the size that's suitable for use on smaller models seems extremely flimsy to me and I'd definitely prefer flat (metal pin) hinges, though pinning them in place is a hassle.