Sealing Hinge gaps?
05-13-2004 | 03:22 PM
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From: Johannesburg, Gauteng, SOUTH AFRICA
Sealing Hinge gaps?
Is it really necesary to seal them? What are the pros and cons?
I've completed my 25% Giles 202 a couple of weeks ago and was wondering about this topic.
Dieter
I've completed my 25% Giles 202 a couple of weeks ago and was wondering about this topic.
Dieter
05-13-2004 | 03:56 PM
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From: in,
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RE: Sealing Hinge gaps?
No cons just pros.
doing so will make the surface more efficient.
Some people believe it prevents flutter, but that's not true.
It's easy to do, so why not.
doing so will make the surface more efficient.
Some people believe it prevents flutter, but that's not true.
It's easy to do, so why not.
05-13-2004 | 05:21 PM
#3
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RE: Sealing Hinge gaps?
I've seen one plane, a top-hinged Mustang, fly with more precise aileron control after covering the bottom gap with a strip of clear plastic (adhered in front of the aileron.) I have not seen such dramatic results from other various seal operations. I question whether, at the slow speeds I fly, much need for sealing control hinge lines exists.
I have seen control surface forces increase, when Monocote is used to seal a hinge line, taxing the servo and receiver battery.
For these reasons, I do not fret about sealing hinge lines. (I do, however, take care to minimize the gap at hinge lines.)
Good luck,
Dave Olson
I have seen control surface forces increase, when Monocote is used to seal a hinge line, taxing the servo and receiver battery.
For these reasons, I do not fret about sealing hinge lines. (I do, however, take care to minimize the gap at hinge lines.)
Good luck,
Dave Olson
05-13-2004 | 05:26 PM
#4
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RE: Sealing Hinge gaps?
Why would you not do it ? It only makes the airplane fly better and it is so easy
to do. I've flown some prety fast pattern ships for a number of years and I for one
beleive it does lessen the chance of flutter and it definitely improves control response.
tommy s
to do. I've flown some prety fast pattern ships for a number of years and I for one
beleive it does lessen the chance of flutter and it definitely improves control response.
tommy s
05-13-2004 | 05:52 PM
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From: League City,
TX
RE: Sealing Hinge gaps?
Like Scar said, there is at least one reason not to do it. On 40 to 60 size planes it greatly increases the control surface resistance (amount of force needed to move the surfaces). This taxes the servos and reduces battery life. I used to seal all my planes, but now I don't worry about it (unless there's a huge gap). On large scale planes, I think it would be more important.
05-13-2004 | 05:59 PM
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RE: Sealing Hinge gaps?
Use clear ultracote instead of monokote... if done right there will be no added resistance whatsoever.
Monokote is thicker and it hardens when heated. Ultracote is much lower temp and stays more flexible. I use UC to seal every hingeline from .15 size gliders all the way up to my 33%+ planes. The other nice thing about UC for sealing is if you happen to mess it up.. it is easily stripped and re-done. Monokote, once applied, is very tough to strip.
Sealing the hinge line on a 40-60 size plane makes perfect sense - not only do you ge tbetter surface response, but it makes a great backup to the CA hinge system. While CA hinges rarely fail, the sealing certainly strengthens them on the high-g surfaces of a 3D plane.
DP
Monokote is thicker and it hardens when heated. Ultracote is much lower temp and stays more flexible. I use UC to seal every hingeline from .15 size gliders all the way up to my 33%+ planes. The other nice thing about UC for sealing is if you happen to mess it up.. it is easily stripped and re-done. Monokote, once applied, is very tough to strip.
Sealing the hinge line on a 40-60 size plane makes perfect sense - not only do you ge tbetter surface response, but it makes a great backup to the CA hinge system. While CA hinges rarely fail, the sealing certainly strengthens them on the high-g surfaces of a 3D plane.
DP
05-13-2004 | 08:08 PM
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From: Soldotna,
AK
RE: Sealing Hinge gaps?
Use the Dave Brown hinge seal. It is a VERY thin clear covering that dissapears when ironed on. If you seal the gaps you will notice that you do not need as much throw to achive the same roll rate, this means you can re-position the linkage to give you more torque and less throw, thus INCREASING the servo life!! If you do not think it helps with flutter you are a 1%er. I have noticed a big difference on both small (electric) and large (40%) planes. Just my .02
Leni
Leni
05-13-2004 | 10:18 PM
#9
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RE: Sealing Hinge gaps?
Look at the gap and think of it as a leak in your wing. Sealing it gives you more response from your throws, no question. Also it decreases your wing loading since your wing area is effectively bigger. Adds resistance to the servo? Only if you do it wrong. Take a piece of ultra coat in your hands and bend it back and forth. It takes next to zero torque. If you apply the covering without giving the hinge enough slack to deflect, then of course it will bind.
AND... it's so easy to do. Why not?
AND... it's so easy to do. Why not?
05-14-2004 | 05:15 AM
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From: Fresno, CA
RE: Sealing Hinge gaps?
ORIGINAL: dieterlubbe
Ok. Now I'm convinced.
But can I use a piece of Scotch tape or something like that, or wont it hold up?
Dieter
Ok. Now I'm convinced.
But can I use a piece of Scotch tape or something like that, or wont it hold up?
Dieter
Any clear thin tape will work - regular clear Scotch tape should work, but I have noticed the frosty Magic tape cracks when repeatedly flexed on other applications. Am planning to use clear packing tape cut to fit...
Cheers!
Jim
05-14-2004 | 12:29 PM
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From: , MA
RE: Sealing Hinge gaps?
I'm another one who no longer seals control surface hinge lines. In my decades of building and flying models of many types including control line, free flight and RC I have never found that sealing control surface gaps cures a flutter problem. Proper wing/aileron design will prevent flutter in the intended speed range of the model.
I have seen wing flutter destroy freeflight models that had NO ailerons or any other control surfaces.
I've built models that had no flutter until I modified them to take tricycle retract landing gear which pushed the speeds up well over 100mph. Sealing hinge lines didn't fix it, slowing it down did.
Now I fly 1/4 scale and 3D with a Sig CAP231EX, two 72-inch Katanas, three U-CAN-Do-3D's and throw in a Pizzaz and a Somethin' Extra. Yep, none of them are sealed and they don't flutter. A bunch of other models that I have do not flutter either.
I'm just relating my experiences and what works for me. I'm not insisting that you don't seal but I don't think you need to be panicked into sealing by some who are only guessing that sealing works.
On the subject of control surface effectiveness, I don't believe I've seen a 3D model with sluggish controls. Its funny to hear that some folks use sealing to make their controls more effective then they use computer transmitter dual rates and high percentages of exponential to reduce that effectiveness.
I have seen wing flutter destroy freeflight models that had NO ailerons or any other control surfaces.
I've built models that had no flutter until I modified them to take tricycle retract landing gear which pushed the speeds up well over 100mph. Sealing hinge lines didn't fix it, slowing it down did.
Now I fly 1/4 scale and 3D with a Sig CAP231EX, two 72-inch Katanas, three U-CAN-Do-3D's and throw in a Pizzaz and a Somethin' Extra. Yep, none of them are sealed and they don't flutter. A bunch of other models that I have do not flutter either.
I'm just relating my experiences and what works for me. I'm not insisting that you don't seal but I don't think you need to be panicked into sealing by some who are only guessing that sealing works.
On the subject of control surface effectiveness, I don't believe I've seen a 3D model with sluggish controls. Its funny to hear that some folks use sealing to make their controls more effective then they use computer transmitter dual rates and high percentages of exponential to reduce that effectiveness.
05-14-2004 | 01:05 PM
#14
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RE: Sealing Hinge gaps?
I am not against it. I used to always do it, and there's no reason not to (unless you just don't feel like it).
But many times, it is simply not needed.
On the other hand, if you have a considerable gap, and you want more control response, then I would say "Seal the gap before increasing the throw".
I have seen many cases (Some on my own planes, some on others) where something as simple as Scotch Tape wedged into the gap has increased the controls effectiveness so much that the deflection had to be DEcreased.
Bottom line, if you need it, do it. If the plane flies fine as is, skip it.
But many times, it is simply not needed.
On the other hand, if you have a considerable gap, and you want more control response, then I would say "Seal the gap before increasing the throw".
I have seen many cases (Some on my own planes, some on others) where something as simple as Scotch Tape wedged into the gap has increased the controls effectiveness so much that the deflection had to be DEcreased.
Bottom line, if you need it, do it. If the plane flies fine as is, skip it.
05-14-2004 | 02:16 PM
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From: in,
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RE: Sealing Hinge gaps?
I have never found that sealing control surface gaps cures a flutter problem.
Read post #2
05-14-2004 | 03:31 PM
#17
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RE: Sealing Hinge gaps?
ORIGINAL: Jemo
You are correct. Sealing gaps will not stop flutter. Doing so however, will make the surfaces more efficient
Read post #2
I have never found that sealing control surface gaps cures a flutter problem.
Read post #2
05-14-2004 | 04:00 PM
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RE: Sealing Hinge gaps?
ORIGINAL: Rocketman_
I'm another one who no longer seals control surface hinge lines. In my decades of building and flying models of many types including control line, free flight and RC I have never found that sealing control surface gaps cures a flutter problem. Proper wing/aileron design will prevent flutter in the intended speed range of the model.
I have seen wing flutter destroy freeflight models that had NO ailerons or any other control surfaces.
I've built models that had no flutter until I modified them to take tricycle retract landing gear which pushed the speeds up well over 100mph. Sealing hinge lines didn't fix it, slowing it down did.
Now I fly 1/4 scale and 3D with a Sig CAP231EX, two 72-inch Katanas, three U-CAN-Do-3D's and throw in a Pizzaz and a Somethin' Extra. Yep, none of them are sealed and they don't flutter. A bunch of other models that I have do not flutter either.
I'm just relating my experiences and what works for me. I'm not insisting that you don't seal but I don't think you need to be panicked into sealing by some who are only guessing that sealing works.
On the subject of control surface effectiveness, I don't believe I've seen a 3D model with sluggish controls. Its funny to hear that some folks use sealing to make their controls more effective then they use computer transmitter dual rates and high percentages of exponential to reduce that effectiveness.
I'm another one who no longer seals control surface hinge lines. In my decades of building and flying models of many types including control line, free flight and RC I have never found that sealing control surface gaps cures a flutter problem. Proper wing/aileron design will prevent flutter in the intended speed range of the model.
I have seen wing flutter destroy freeflight models that had NO ailerons or any other control surfaces.
I've built models that had no flutter until I modified them to take tricycle retract landing gear which pushed the speeds up well over 100mph. Sealing hinge lines didn't fix it, slowing it down did.
Now I fly 1/4 scale and 3D with a Sig CAP231EX, two 72-inch Katanas, three U-CAN-Do-3D's and throw in a Pizzaz and a Somethin' Extra. Yep, none of them are sealed and they don't flutter. A bunch of other models that I have do not flutter either.
I'm just relating my experiences and what works for me. I'm not insisting that you don't seal but I don't think you need to be panicked into sealing by some who are only guessing that sealing works.
On the subject of control surface effectiveness, I don't believe I've seen a 3D model with sluggish controls. Its funny to hear that some folks use sealing to make their controls more effective then they use computer transmitter dual rates and high percentages of exponential to reduce that effectiveness.
The only thing sealing the gaps buys you is a more crisp control response and much better near stall speed wing loading. I had a P-51 tip stalling on my without sealed gaps, I sealed the gaps and no more tip stalls.
Don't do it if you don't want to - it purely is optional.. but it does make a diff. I have yet to see a competitive pattern or IMAC ship that does not have gap sealing of some sort.
DP
05-14-2004 | 10:47 PM
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From: poway, CA,
RE: Sealing Hinge gaps?
Sealing gaps reduces your chance of flutter. Flutter is caused when the airstream is bucked by the vortex of the gap. If there is little or no gap then the chances are reduced. The larger the gap, the greater the chance of flutter. Low flutter will cause your linkages to get sloppy. If you are properly installing CA hinges then you should have a gap the size of a T pin shaft. Using clear tape is by far the easiest. Just fold it in half, sticky side out and carefully apply it to the hinge.
No modern day full scale has a hinge gap(hmmm wonder why?) They are either sealed with cloth or shielded with metal overlays to direct airflow. Come on! get real guys. A few minutes of your time for a little extra insurance. This is a no brainer.
No modern day full scale has a hinge gap(hmmm wonder why?) They are either sealed with cloth or shielded with metal overlays to direct airflow. Come on! get real guys. A few minutes of your time for a little extra insurance. This is a no brainer.
05-15-2004 | 09:15 AM
#21
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RE: Sealing Hinge gaps?
IMO on the average sport flyer plane sealing the hinge gap is not required (unless the gap is large) and actually noticing a difference would be nearly impossible. When I first heard of sealing the hinge gap I went and sealed a couple of my existing planes that I had flow for awhile. When I flew them again I honestly could not tell any difference after the sealing. Again IMO.
05-15-2004 | 10:14 AM
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From: Brandon, MS
RE: Sealing Hinge gaps?
Just some thoughts,
If you think about it a little bit then 3D planes with large throw setups can benifit from having the hinge gaps sealed. When you deflect a large surface 45 degrees a lot of air is going to be forced thru the gap, thats air the could be put to use going over the control surface.
Now some folks will come back with my hinge line has no gap, then ***** when the CA hinge fails from flexing over such a short distance.
If put on properly there should be no noticeable increase in effort needed to flex the surface after sealing.
Ed M.
If you think about it a little bit then 3D planes with large throw setups can benifit from having the hinge gaps sealed. When you deflect a large surface 45 degrees a lot of air is going to be forced thru the gap, thats air the could be put to use going over the control surface.
Now some folks will come back with my hinge line has no gap, then ***** when the CA hinge fails from flexing over such a short distance.
If put on properly there should be no noticeable increase in effort needed to flex the surface after sealing.
Ed M.
01-05-2005 | 09:41 PM
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From: Sebastian,
FL
RE: Sealing Hinge gaps?
Please, can someone give a detailed discription of how to seal hinge gaps using clear packing tape? a pic or two would be nice. I know it is probably very simple, but I am new and have never seen it done and obviously have not done it myself. Thanks a bunch.[8D]
