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General control line discussion => Open Forum => Topic started by: Allan Perret on March 08, 2009, 07:37:31 PM

Title: Hinge lines, seal or not ??
Post by: Allan Perret on March 08, 2009, 07:37:31 PM
Just starting putting my new bird thru the paces, 3 flights. Magnum weighting 60 oz. It's lite (quick for you engineers that already know the formula, what's that work out to for wing loading). Feels like it has power steering. Its on rails(groovin) in level flight, and has a great corner. Probably has more corner than I can handle right now (advanced flyer in the 480's). I'm sure it has the performance to take me into the 500's. So is there really anything to be gained by sealing the hinge lines, I can't imagine what.

Allan Perret
Title: Re: Hinge lines, seal or not ??
Post by: Clint Ormosen on March 09, 2009, 09:01:19 AM
I'm sure it has the performance to take me into the 500's. So is there really anything to be gained by sealing the hinge lines, I can't imagine what.

Allan Perret



Doesn't sound like it. I do mine on principal
Title: Re: Hinge lines, seal or not ??
Post by: Bob Reeves on March 09, 2009, 09:30:41 AM
Several will say you should do it no matter what but have never had sealed hinges make any difference whatsoever on any of my ships. If they had a trim quirk they still had it with sealed hinges and has never made a difference in the turn rate so I quit even trying it. Maybe if you gaps were uneven or not tight it might help but if you don't have any trim issues don't bother trying to fix something that isn't broken.
Title: Re: Hinge lines, seal or not ??
Post by: john e. holliday on March 09, 2009, 03:35:41 PM
As the saying goes, "You can't fix it if it aint broke".   If you likt it don't mess with it.  DOC Holliday
Title: Re: Hinge lines, seal or not ??
Post by: SteveMoon on March 10, 2009, 06:20:55 AM
If the plane feels like it "is on rails" and has plenty of corner,
then I see no reason why you would need to seal the hinge
lines. Also, with only 3 flights on the plane, you've still got
quite a few trim flights to go. Get some more flights in, get
used to the plane, and then make a decision on whether to
seal the hinge lines. It sounds to me like you don't need to.

Steve
Title: Re: Hinge lines, seal or not ??
Post by: Dennis Adamisin on March 10, 2009, 05:26:28 PM
The first airplane I ever used seals on, the seals had a BIGGER impact on the corner than 4oz of tailweight.  SInce then I do not even think about it every bird (CL or RC) gets seals - period.

Of course your mileage may vary...

Prior to the bird mentioned above, I built lots of successful airplanes without hinge seals.  Maybe some of those birds could have been even better with seals, maybe they would not have made any difference.  However, seals REMOVE any influence that hinge gaps can possibly have - for that reason alone I cannot think of a good reason not to use them.
Title: Re: Hinge lines, seal or not ??
Post by: James C. Johnson on March 10, 2009, 06:22:42 PM


I was reading an old Stunt News (Nov/Dec 2001) and found this in an article by Tom Dixon.. "tape the hinge line. You'll need only half as much deflection once the gap is sealed.."

This was written in relation to trimming a crooked wing and trim tabs.

Here is how I seal my hinge line.. taffeta .. $1.50 for one square yard .. enough to last forever..

Jim

(http://imgs.inkfrog.com/pix/campsurf/HingePICT0001.JPG)

(http://imgs.inkfrog.com/pix/campsurf/HingePICT0002.JPG)

(http://imgs.inkfrog.com/pix/campsurf/HingePICT0003.JPG)
Title: Re: Hinge lines, seal or not ??
Post by: Randy Powell on March 10, 2009, 06:36:15 PM
I usually fly the plane at least once before sealing the hingeline. Over the past 10 years or so, all but two planes flew better with the hinge line sealed. The two that didn't were obscenely light and probably benefited from the loss of lift. Oh, and one had only the outboard hinge line sealed. Long story on that. It can be a trimming tool, too.
Title: Re: Hinge lines, seal or not ??
Post by: Larry Fulwider on March 10, 2009, 06:52:16 PM
. . . So is there really anything to be gained by sealing the hinge lines, I can't imagine what.

Allan Perret


Or, reversing that question, is there anything to be lost? I have never heard anyone say that sealing hinge lines caused them a problem.

But then, I go out on my porch every morning and snap my fingers three times. The reason is to keep herds of stampeding elephants away. My neighbors laugh, but I say, "Hey, do you see any elephants?"  ;)

Sealing hinge lines may be like snapping your fingers to keep elephants away for most models. I don't know. But, hey, seen any elephants?

Larry Fulwider
Title: Re: Hinge lines, seal or not ??
Post by: Leo Mehl on March 10, 2009, 07:34:50 PM
I round the trailing edge of the wing and the leading edge of the flap. It is easyier to get things to fit tight. I have not had to tape the hinge line on my last 6 planes I have built. I think if you use a diamond shape on the leaging edge of the flap you should tape them. I have had planes where the taping definatly helped but I have a problem with the oil staying in the hinge line between the wing and flap and that makes for some serious soaking problems in that area. If you don't have to tape them this area is easier to clean! HB~> HB~>