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Author Topic: trim tab  (Read 3816 times)

Offline Chris Belcher

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trim tab
« on: June 22, 2014, 03:01:19 PM »
How does one add a trim tab to the flap? Ihave a high wing and it rolls in on maneuvers but added tip weight makes it worse. Do you cut a slot in the trailing egde of the flap/ How do you get the angle you need?
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Offline Chris Belcher

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Re: trim tab
« Reply #1 on: June 22, 2014, 04:51:11 PM »
its a cardinal so the flaps go alllthe way to the end of the wing....does it go on the trailing edge of the flap? I assume when you say non moving you mean the trailing edge of the wing outboard of the flap...like on a bucaneer?
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Offline Tim Wescott

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Re: trim tab
« Reply #2 on: June 22, 2014, 07:51:39 PM »
I wouldn't add a tab unless the only other alternative was stomping the plane into the ground.

Is the wing low when you're inverted?  Or have you not had the courage to check?

Can the wing be twisted?  (I should know, but do not, if the Cardinal wing has a D-tube leading edge).  If the wing can be twisted, then check it for warps and correct them.

If you can't take the warp out, tweak the flaps.  Grasp the flaps right where the horn attaches, and twist one up and one down.  If the horn isn't too big or made out of too highly tempered wire, you should be able to put a set into it.  I usually twist in a bit extra, then twist back -- that keeps it from relaxing to less 'tweak' than I put in.

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Offline Mike Haverly

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Re: trim tab
« Reply #3 on: June 22, 2014, 07:54:39 PM »
Tim is right.  It would be a lot better idea to remove the problem that is causing one wing to be higher than the other.  Most likely a warp in one or both wings or either flap.  Cardinal's have excessively large flaps to begin with and you could get the wings level with a tab but it will make things worse elsewhere.   If it is covered with film, removing a warp is a simple matter of applying heat and twisting the warp away.  Even silkspan and dope can be fixed.  Crooked airplanes never fly correctly and will make you unhappy.
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Offline Tim Wescott

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Re: trim tab
« Reply #4 on: June 22, 2014, 08:19:28 PM »
Quote from: Ty Marcucci on June 22, 2014, 08:02:19 PM
Well I gave one answer to adding a trim tab. I don't know if you have a warp or other alignment problems. Have you tried using the trim chart posted on here by Paul Walker?  Use it first before adding a trim tab. Do like the above posts suggest. Do you have a "contest grade" flyer near you? In other words a coach that can help in the trim phase. I say "contest grade" flyer instead of "hot shot"as that term upsets the hot shots LL~ LL~ LL~ LL~

In most of our contests around here, if you can start a wingover and crash without ever recovering to level flight you can get a trophy in beginner -- does that make you "contest grade"?
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Offline Tim Wescott

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Re: trim tab
« Reply #5 on: June 22, 2014, 10:43:29 PM »
Quote from: Ty Marcucci on June 22, 2014, 08:59:33 PM
I've been meaning to talk to you about your wing overs Tim.. LL~ LL~ LL~ LL~ LL~ LL~ LL~

I only missed the second turn of the wingover once, when I was transitioning from the beginner pattern to the real pattern.  The internal narrative went "up, over, now which way was I going to -- dang!"
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Offline john e. holliday

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Re: trim tab
« Reply #6 on: June 23, 2014, 10:34:08 AM »
My self I need to see the plane.  You say high wing.  Is that like a Piper Cub or are you saying the wing flies with the out board high.  Also is it outboard low when inverted.  If so you have a warp.  Get rid of it.  No amount of wing tip weight will cure it.  Also do not tweak your flaps as it will just compound the trimming of the plane.  How about a picture?
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Offline Tim Wescott

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Re: trim tab
« Reply #7 on: June 23, 2014, 01:07:27 PM »
Quote from: john e. holliday on June 23, 2014, 10:34:08 AM
If so you have a warp.  Get rid of it.  No amount of wing tip weight will cure it.  Also do not tweak your flaps as it will just compound the trimming of the plane.  How about a picture?

If you have a visible warp, and it can be fixed, yes, fix it.  Then if you still have an issue tweak the flaps.  (If the flaps are tweaked in the direction of the problem -- straighten them!).

As with a trim tab, tweaking the flaps to fix a wing warp should only be done if you absolutely can't get the warp out -- and then you should start building another plane, because what you have will always be a dog.  This is why the top guys are obsessed with building dead straight airplanes that won't get all warped up over time.
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Offline RC Storick

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Re: trim tab
« Reply #8 on: June 23, 2014, 01:29:33 PM »
All wood changes due to humidity and temperature. It can be trained to stay relatively straight with steam. Wood is a living thing and will continue to change throughout the models life. Super heated steam releases the binders in the wood allowing you to move it in any direction. Steaming is much better than tweaking and trim tabs.
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Offline Chris Belcher

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Re: trim tab
« Reply #9 on: June 23, 2014, 03:29:37 PM »
OK...it's an arc cardinal covered with monokote that flew great until it died at the top of the clover and fell straight out of the sky...I tried to run like Forrest Gump but it nosed in and damage was done to the outboard wing tip area. I patched 'er back together and guess it ended up with a warp on that side. If it's wing high upright I suppose it obviously is curved "down" so I will try to remove the warp before I try trim tabs...
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Offline john e. holliday

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Re: trim tab
« Reply #10 on: June 24, 2014, 08:48:15 AM »
Good move.
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John E. "DOC" Holliday
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Offline Tim Wescott

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Re: trim tab
« Reply #11 on: June 24, 2014, 09:39:15 AM »
Quote from: Chris Belcher on June 23, 2014, 03:29:37 PM
OK...it's an arc cardinal covered with monokote that flew great until it died at the top of the clover and fell straight out of the sky...I tried to run like Forrest Gump but it nosed in and damage was done to the outboard wing tip area. I patched 'er back together and guess it ended up with a warp on that side. If it's wing high upright I suppose it obviously is curved "down" so I will try to remove the warp before I try trim tabs...

Do a visual inspection!  You may find that the leading edge, trailing edge, or spar is kinked.  If so then warping the wing for best behavior (i.e., Phil Cartier's suggestion) is going to be the best you'll do -- but it'll never be completely right.  If you do that visual inspection, you'll know why.
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Offline Chris Belcher

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Re: trim tab
« Reply #12 on: June 25, 2014, 10:46:54 AM »
Sounds like it's time for a new plane!!!! YEA!! ;D
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Offline john e. holliday

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Re: trim tab
« Reply #13 on: June 26, 2014, 09:52:55 AM »
I'm on your wifes side.   Just fix the warp.      Now I don't know your wife, but I know that is what my wife would say.
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John E. "DOC" Holliday
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Offline Chris Belcher

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Re: trim tab
« Reply #14 on: June 26, 2014, 11:12:53 AM »
Now that's funny...yeah...I'll fix the warp...if it has one. Better a warped wing than a warped wife!
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Offline Mark Scarborough

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Re: trim tab
« Reply #15 on: June 26, 2014, 01:11:45 PM »
Quote from: Tim Wescott on June 22, 2014, 08:19:28 PM
In most of our contests around here, if you can start a wingover and crash without ever recovering to level flight you can get a trophy in beginner -- does that make you "contest grade"?
uh technically Tim,, if you dont pull out inverted its not an official flight,, so you COULD be disallowed a trophy,,

just sayin,,
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Offline Steve Helmick

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Re: trim tab
« Reply #16 on: June 26, 2014, 09:33:32 PM »
Quote from: Mark Scarborough on June 26, 2014, 01:11:45 PM
uh technically Tim,, if you dont pull out inverted its not an official flight,, so you COULD be disallowed a trophy,,

just sayin,,

Not in Beginner, Mark. Because they ain't s'posed to pull out inverted. I think their flight is official once the takeoff is completed or after 3 laps or...I'd better go read the Beginner rules again. It's been awhile since we had a Beginner like Tim...  S?P Steve

PS: Back on topic, I'd suggest giving the flaps and elevators a good look to be certain they are not twisted, tweeked, warped or misaligned!
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