2Meter sailplane - Hinges?
07-13-2007, 04:57 AM
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2Meter sailplane - Hinges?
I have been out of this hobby for 20 years and now I have returned, this time to fly sailplanes. I'm sure some things have changed in the past 20 years in regards to building supplies and techniques. I have a simple question: I am building a 2 meter sailplane and would like to know what are the best hinges to use on a plane of this size? I was planning to use the "old" industry standard (of 20 years ago) and use Dubro standard size hinges. Are there other and better methods to use?
Thanks,
Thanks,
07-13-2007, 05:46 AM
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RE: 2Meter sailplane - Hinges?
Tom,
First of all, welcome back! I hope your return is an enjoyable one.
As far as hinges go, it would depend on the plane itself and a couple of other things like the covering you'll use and the structure. A light, stick type structure may have to be reinforced to use CA hinges, pin hinges or even your old Du-Bro standards. For such an application, you may want to use hinge tape or hinges made from covering material (I have a Gentle Lady with Monokote hinges. 10 years and no problems.)
If you belong to a club, ask around as to what other people are using. Sometimes doing the research is half the fun. Good Luck.
papermache
First of all, welcome back! I hope your return is an enjoyable one.
As far as hinges go, it would depend on the plane itself and a couple of other things like the covering you'll use and the structure. A light, stick type structure may have to be reinforced to use CA hinges, pin hinges or even your old Du-Bro standards. For such an application, you may want to use hinge tape or hinges made from covering material (I have a Gentle Lady with Monokote hinges. 10 years and no problems.)
If you belong to a club, ask around as to what other people are using. Sometimes doing the research is half the fun. Good Luck.
papermache
07-13-2007, 06:01 AM
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RE: 2Meter sailplane - Hinges?
The new CA hinges work in the same places the DuBro ones would. They're lighter and somewhat easier to use. The are not as free, but the jury is out on how great an effect that is.
If you do use the DuBro, look very hard at the "new" hinge glue. It makes the job of gluing in those puppies almost effortless. When I got back into this hobby after many years away, the one thing I still dreaded was epoxying those hinges. And I didn't trust or respect the CA ones. First thing I did was try and TEST the DEVIL out of this new hinge glue. It's as good as epoxy and none of the problems. Better because with a damp paper towel, it's almost impossible to glue the hingeline solid, something that's very possible with epoxy.
Now, after a year or so and some 15 or more ARFs later, I've got no problem using the CA hinges. They're very, very good. And lots easier to install. And I no longer worry about their stiffness causing any problems. Matter of fact, they might be the best hinges possible against flutter. And with the new batterychargers that tell you how much capacity your flying took, it appears they don't cause anything like excess servo load.
If you do use the DuBro, look very hard at the "new" hinge glue. It makes the job of gluing in those puppies almost effortless. When I got back into this hobby after many years away, the one thing I still dreaded was epoxying those hinges. And I didn't trust or respect the CA ones. First thing I did was try and TEST the DEVIL out of this new hinge glue. It's as good as epoxy and none of the problems. Better because with a damp paper towel, it's almost impossible to glue the hingeline solid, something that's very possible with epoxy.
Now, after a year or so and some 15 or more ARFs later, I've got no problem using the CA hinges. They're very, very good. And lots easier to install. And I no longer worry about their stiffness causing any problems. Matter of fact, they might be the best hinges possible against flutter. And with the new batterychargers that tell you how much capacity your flying took, it appears they don't cause anything like excess servo load.
07-13-2007, 06:22 AM
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RE: 2Meter sailplane - Hinges?
20 years [X(]
Hope you get a lot of time circling for thermals in the years to come then
As already mentioned the only "new" kind of hinges are the CA-hinges.
If the ailerons and elevator have top-hinging I prefer the oldfashioned hinge-tape. Always use MPX tape, and it never slide a mm! My old MPX Schampus have flown for 20 years and the ailerons are where they were mounted in late 80-ies. At this moment I work on my 1:3,5 Moswey III adding just hinge-tape for the ailerons on this beauty.
The well-known hinges as Dubro, Robart etc still work as they did earlier; good. As da Rock said, CA-hinges works! But I have one advice: when the hinge-slots are made, drill a small hole in the center of the slots. I use 1,5 - 2mm. This allows the CA to reach the entire length of the hinges.
Else: the air is as thick (or thin) as 20 years ago, get airborne and have fun
Hope you get a lot of time circling for thermals in the years to come then
As already mentioned the only "new" kind of hinges are the CA-hinges.
If the ailerons and elevator have top-hinging I prefer the oldfashioned hinge-tape. Always use MPX tape, and it never slide a mm! My old MPX Schampus have flown for 20 years and the ailerons are where they were mounted in late 80-ies. At this moment I work on my 1:3,5 Moswey III adding just hinge-tape for the ailerons on this beauty.
The well-known hinges as Dubro, Robart etc still work as they did earlier; good. As da Rock said, CA-hinges works! But I have one advice: when the hinge-slots are made, drill a small hole in the center of the slots. I use 1,5 - 2mm. This allows the CA to reach the entire length of the hinges.
Else: the air is as thick (or thin) as 20 years ago, get airborne and have fun
07-13-2007, 06:31 AM
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RE: 2Meter sailplane - Hinges?
Thanks everyone for your advice and tips. Things have certainly changed in the last 20 years!!![X(] As always, the friendly people here have helped me get back into this great hobby with the added "knowledge" and "nowhow" of todays technology!!
Thanks again,
Thanks again,
07-13-2007, 08:18 AM
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RE: 2Meter sailplane - Hinges?
Hi Tom
If you are intertested in keeping that 2 metre up in the air as long as you can you will want to reduce drag as much as you can. Wether on the slope or thermal flying extra drag saps performance and means you will come down all the quicker. The hinge line in all surfaces is a very large drag source if it is not sealed, even a phsically 'tight' mechanical hinge will leak air through the hinge line.
As a contest pilot I would not use the Dubro hinge or the CA hinge or similar types as they basically come from the 'powered' form of our sport where drag is not so critical. All these types of hinge do not seal the joint at the hinge line. There are 3 commonly used joints which are sealed and they all rely on top hinging. Each suggestion assumes you have sanded the wing TE and surface LE to 45 degrees each for movement:
1. The 'Monokote' joint of whatever covering you prefer is the simplest. Just butt the tops of the surfaces and iron the film right over the joint. Turn the surface 180 degrees so its top surface lies on the top surface of the wing and iron on a sliver of Monokote over the exposed joint, making sure the top and bottom pieces 'stick together' at the hinge line. Very easy, very light and no bonding.
2. The use of hinge tape is identical, except you use tape instead of Monokote.
3. Silicone joints for higher performance models. This is worthy of an article all on its own and is too large to describe here, but if you would like to read about it PM me and I will send you a leaflet.
Cheers
Glidagida
www.rc-sailplane.com.au
If you are intertested in keeping that 2 metre up in the air as long as you can you will want to reduce drag as much as you can. Wether on the slope or thermal flying extra drag saps performance and means you will come down all the quicker. The hinge line in all surfaces is a very large drag source if it is not sealed, even a phsically 'tight' mechanical hinge will leak air through the hinge line.
As a contest pilot I would not use the Dubro hinge or the CA hinge or similar types as they basically come from the 'powered' form of our sport where drag is not so critical. All these types of hinge do not seal the joint at the hinge line. There are 3 commonly used joints which are sealed and they all rely on top hinging. Each suggestion assumes you have sanded the wing TE and surface LE to 45 degrees each for movement:
1. The 'Monokote' joint of whatever covering you prefer is the simplest. Just butt the tops of the surfaces and iron the film right over the joint. Turn the surface 180 degrees so its top surface lies on the top surface of the wing and iron on a sliver of Monokote over the exposed joint, making sure the top and bottom pieces 'stick together' at the hinge line. Very easy, very light and no bonding.
2. The use of hinge tape is identical, except you use tape instead of Monokote.
3. Silicone joints for higher performance models. This is worthy of an article all on its own and is too large to describe here, but if you would like to read about it PM me and I will send you a leaflet.
Cheers
Glidagida
www.rc-sailplane.com.au
07-13-2007, 12:49 PM
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RE: 2Meter sailplane - Hinges?
I use 3M #190 tape (Ace Hardware carries it in little rolls, about $1.50 a roll) and it works great, even on my 60", 70 ounce sled. On a floater, no problem at all. Just put a bevel on one side of the control surface, and leave a tiny gap between the fin and rudder, say 1/32", to allow for movement.
Other tricks you can use are: Cut the 3/4" tape width down to 3/8", to save some weight. You can also use this tape to make "wipers" to seal the gap on the opposite side of the surface, i.e. the bevel side. Cut your tape the length you want it, and apply it to a clean metal yardstick with half its width overhanging. Sprinkle talcum powder on the exposed edge- that side will slide on the edge of the moving control surface to seal the gap. This is more important with faster planes, on things like the ailerons where the thickness of the wing means there will be a large gap.
If you want to REALLY have a gucci hinge, as Glidaguida says above, try googling "silicone hinges". Those things are amazing. No visible tape, just a nearly invisible gummy hinge in the gap. You can also substitute "Goop" glue for the silicone. This works better on fiberglass planes, but the goop will stick to monokote, which silicone has trouble with. These hinges are so tough you couldnt pull the control surface off the plane without breaking something first.
Other tricks you can use are: Cut the 3/4" tape width down to 3/8", to save some weight. You can also use this tape to make "wipers" to seal the gap on the opposite side of the surface, i.e. the bevel side. Cut your tape the length you want it, and apply it to a clean metal yardstick with half its width overhanging. Sprinkle talcum powder on the exposed edge- that side will slide on the edge of the moving control surface to seal the gap. This is more important with faster planes, on things like the ailerons where the thickness of the wing means there will be a large gap.
If you want to REALLY have a gucci hinge, as Glidaguida says above, try googling "silicone hinges". Those things are amazing. No visible tape, just a nearly invisible gummy hinge in the gap. You can also substitute "Goop" glue for the silicone. This works better on fiberglass planes, but the goop will stick to monokote, which silicone has trouble with. These hinges are so tough you couldnt pull the control surface off the plane without breaking something first.
