highflyinguy

Hi, my name is Jerry Bohn , from Longmont, Colorado.
I am starting to build a Sig MidStar 40 and am not familiar wiyh the flat type hinges that came with the kit, they seem that they would be a lot more stiff than a barrel type hinge.
I am getting back to R/C after a 15 year layoff and have heard Klett hinges are of good quality. Unfotunatly my local hobby shops do not stock them and was wodering, 1-weather to use the Sig hinges in the kit, 2- If anyone knows of a source of getting Klett barrel hinges.
How bout them Sig Hinges?

bojangle

Hi Jerry
I'm your neighbor couple hundred miles west of you. As a Square Dance Caller, I used to visit your city regularly.

I used Klett hinges only for 25 years, but Goldberg quit making them. Fortunately Dubro makes a similar hinge. A lot of people use the flat hinges like the ones that came with your kit because they are inexpensive and quick. I won't use them. I always felt real planes deserve real hinges.

Dubro makes 3 sizes, small, regular and large. For the Midstar, you should use the regular, part number 117. If your LHS doesn't have them, Tower Hobbies number is DUBQ2025 for a package of 15. You will need 10 for the ailerons, 6 for the elevators, 3 or 4 for the rudder.

You will also need 3-4 pieces of music wire, size .025 . It's a standard size, your LHS should have it. I buy the size by the full tube. By using the wire as a continuous pin, you can remove/replace moving parts. Also you can have the hinges accurately aligned and installed before you cover. I don't want glue anywhere near my plane after it's covered. I developed this system many years ago, probably the only one that does it. But if you will use my system, you will never touch a "flat" hinge again. Hinge gap is almost zero, and there is no resistance or binding to the servo.

I am working on some drawings/photos and instructions for the system, hope to have it ready in a few days. If you like, I will post it here, or PM you my email address. The procedure is very simple, but a little lengthy to explain here, although others may be interested.

Everyone has their own construction methods, including hinging. The way I do it works for me, I don't criticize others for their methods, which work for them. But I am always happy to share my methods for what they are worth.

Bob

JimTrainor

I just put some Dubro hinges in my LT-40.

I wish I had read bonjangle's advice about the music wire install method to get them aligned. My install is not horrible but there is some small misalignment that I will attemp to avoid next time around.

I'm going to follow bojangles advice when when I hinge my 1/4 scale cub that is awaiting covering.

I think the Dubro hinges look better installed than Robart hinges, if you care about such things.

bojangle

When the Klett hinges were available, I had what I considered the perfect system. The factory pins were .025 exactly, so the .025 music wire was a perfect fit, though alignment was super critical.

When Goldberg discontinued the Klett, I almost cried. [] What to do? I saw the Dubro hinges in the catalog and ordered some. The Dubro factory pins are .028, which is a wire size 22 (Imperial), only available from piano manufacturer sources, not from K&S. However, I found with the extra tolerance, I am able to embed the hinges deeper and still get the wire through later. By wrapping the Monokote over the edge of the surface, any slack is taken up by the covering and their is no slop (and no hinge gap). Just slit and remove covering in the hinge area.

This system is quite exacting, little room for errors. I recommend practicing on some scrap "mock" stab and elevator pieces, including covering the sample. It is extremely important to put a 45 degree taper both sides of slits on the movable surface. I didn't put enough taper on one plane, after it was covered I had a tough time getting the wire through the barrels, and didn't have enough control movement. I had to cut the covering from the movable surface hinge edge, increase the taper then add small strip of covering.

I'm still working on complete instructions, but will add this now. After making the slits, and I make them very wide and pretty loose fit, I make a 3/32" to 1/8" hole all the way through the wood in the middle of the slot area. This is to wick CA in. Assemble all the hinges, both surfaces and continuous wire, with the barrels facing the same direction, push, jiggle, pull, whatever it takes to get the hinges "bottomed out" and perfectly aligned. When it is correct, the wire "pin" will slide very easily, letting you know there is no binding, all barrels exactly in line. Double check everything before gluing. Holding the surface vertical, barrels facing up, apply only one small drop in the hole. Then wait. If the glue wicks in the barrel, the hinge is ruined. After each hole has one drop, pull the wire pin out. Separate the surfaces, then again holding it so the barrels are facing up (on top), apply 2 drops to each hole on both sides. Don't bother pinning the hinge with toothpicks, not necessary. I make the glue holes big, easy to fill with Hobbylite filler. Don't ever apply CA if the barrels are pointing down.....lesson learned.

I know one guy that always tried to push epoxy down in the slot with a toothpick. I suggested the hole method, but he said he didn't want to drill holes in his new plane. OK

If you don't want to leave the continuous hinge pin, you can also make individual pins from soft dressmaker pins or t-pins. Just caliper the diameter, most pins are about .026 to .027. Make a small bend, insert the pin, then bend the other end with tiny needle nose pliers. If you ever need to remove the piece, the soft wire lets you straighten the bend and pull it out. I just like the continuous wire since it helps to seal the gap. If you use the full wire, make a bend on one end, twist it sideways and poke the bend into the edge of one surface, it won't come out by itself that way. I forgot to do this on one plane, when I landed the wire had almost vibrated out.

More later, wife needs the phone
Bob

MinnFlyer

My Feedback: (4)

Jerry, the hinges you got with the kit are fine. I use them on everything except Giant Scale. They are extremely easy to use to, but they must be done right.

Take 5 minutes and read this "How To" article:

http://www.rcuniverse.com/magazine/a...?article_id=55

bojangle

Yes, the flat hinges work fine, properly installed. And as I said, if that works for you and others, great. If you re-read my first post, I didn't say "Don't use them", I said, "I won't use them". All I am trying to do is help those who want to use the pinned hinges do it properly, based on my past successes (and failures). Granted, my method is very complicated, tedious, and takes a lot of patience. Not to mention the few hours it has taken me to explain it lol......

I think I've covered the system well enough. If anyone is interested in more detail, just PM me. No need to hammer it further here.

It's up to Jerry to decide. I am not trying to influence him, only help him.

Bob

highflyinguy

bojangle, Ive been searching the webs and found Klett is still alive and will sell on line. They are under a search of Klett Plastic products. http://www.klettplastics.com/pages/3/index.htm
Thanks for the tip on installing hinges with your method.

bojangle

A final note, something I forgot. Before trying to insert the continuous wire pin through the hinges, sharpen the end to a fine point with a file or emory board. After the parts are covered, the point will guide the wire through each hinge barrel.

For the rudder wire, I bend the wire over the fin about 1/2", make an upward bend, then a 180 degree small loop, cut off leaving about an inch, sharpen the end and push it down into the fin, capturing a small rubber band for the antenna.

Bob

Tired Old Man

My Feedback: (1)

Way too much work unless it's a scale project. The ca hinges will work fine with the mud star. Just add a couple to each surface to make yourself feel comfortable. Non scale large planes work well and look good with Robart hinge points if you install them right. Scale is another story.

spokman

My Feedback: (2)

The whole model is a lot of work. I think taking some extra time to do hinging is a good idea. Unless CA hinge manufactures post MTBF and other test specs on their hinges I'm not inclined to use them unless necessary. If you put a plastic, IE Robart hinge on properly you will have confidence that it will not fail. There are to many stories on this board about CA hinges failing.

CCRC1

My Feedback: (13)

Highflyinguy is correct. Klett plastics is still in business, they just sell direct instead of through a distributor. I just bought some tailwheels from them a month or so back.

bojangle

I never considered any part of building planes actual "work". Work is what I do so I can afford to build planes.

Way I figure, if I'm going to spend several weeks, sometimes months building a great looking plane, why take shortcuts on the hinges. A small sport plane deserves just as much time and effort as a scale project. If I were not willing to make the effort, I would just buy an ARF and go flying.

Most of my planes are my own design. After test flights, I may decide to alter a component. Or a rudder gets broken on a not so perfect landing. It's so nice to be able to just pull a few pins and make the change.

Most modelers seem to consider hinging one of those dreaded tasks that just has to be done. I fine the task enjoyable. When you find a system that works for you, whether it be CA hinges or pinned, you stay with it.

To all, thanks for the info about Klett. I just ordered 200, that should last me awhile.

Bob.......Different strokes for different folks...