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larger trim tab

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jdbutterfield(at)yahoo.co
Guest

Posted: Mon Feb 11, 2008 10:27 am Post subject: larger trim tab

hi guys.

i have the small trim tab on my elevator and was

wondering if the new (larger) trim tabs connects to

the old (small tab) trim motor arm.  if it will, i

believe i will make the larger tab before i paint.  If

every thing must be moved, is it worth it for the

larger tab.

john butterfield

XL, corvair

torrance, ca

Be a better friend, newshound, and 

know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ

victorbravo(at)sbcglobal.
Guest

Posted: Mon Feb 11, 2008 1:16 pm Post subject: larger trim tab

Trim tabs can cause flutter if they are not done correctly and securely. 

On a super-light structure like a Zenair aircraft elevator, elevator 

flutter would be an INSTANT catastrophic situation.



This is one of those things where something that doesn't seem like a big 

safety risk can cause a safety risk.



Larger trim tabs can be done safely for sure, don't be immediately 

afraid of it, but you just have more to think about and more things to 

do to make it safer. And you DO have to check with ZAC because they know 

how large/heavy/flexible of a trim tab is OK and what is too much.



john butterfield wrote:

 	  Quote: 	
		   



 hi guys.

 i have the small trim tab on my elevator and was

 wondering if the new (larger) trim tabs connects to

 the old (small tab) trim motor arm.  if it will, i

 believe i will make the larger tab before i paint.  If

 every thing must be moved, is it worth it for the

 larger tab.

 john butterfield

 XL, corvair

 torrance, ca

 Be a better friend, newshound, and 

 know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ

barcusc(at)comcast.net
Guest

Posted: Mon Feb 11, 2008 1:48 pm Post subject: larger trim tab

I spoke with the guys at Zenith about removing the small trim tab and 

replacing it with the larger one, they said it was OK. However, it was 

suggested I reinforce the area near the trim motor with "L" angle since it 

would be off center. I have not done it yet but I have already bought the 

larger trim tab.

Clyde Barcus

601 XL



---

planecrazydld(at)yahoo.co
Guest

Posted: Mon Feb 11, 2008 2:22 pm Post subject: larger trim tab

back when I was still working on the XL I was planning to simply build the half span tab into both halves of the elevator. It looked to me like the weight penalty would be about 6-8 ounces and if the authority was not needed the tab deflection would have simply been less than with a single tab...



Bill Berle <victorbravo(at)sbcglobal.net> wrote:[quote] --> Zenith-List message posted by: Bill Berle 



Trim tabs can cause flutter if they are not done correctly and securely. 

On a super-light structure like a Zenair aircraft elevator, elevator 

flutter would be an INSTANT catastrophic situation.



This is one of those things where something that doesn't seem like a big 

safety risk can cause a safety risk.



Larger trim tabs can be done safely for sure, don't be immediately 

afraid of it, but  you just have more to think about and more things to 

do to make it safer. And you DO have to check with ZAC because they know 

how large/heavy/flexible of a trim tab is OK and what is too much.



john butterfield wrote:

[quote] --> Zenith-List message posted by: john butterfield 



 hi guys.

 i have the small trim tab on my elevator and was

 wondering if the new (larger) trim tabs connects to

 the old (small tab) trim motor arm.  if it will, i

 believe i will make the larger tab before i paint.  If

 every thing must be moved, is it worth it for the

 larger tab.

 john butterfield

 XL, corvair

 torrance, ca

 Be a better friend, newshound, and 

 know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ 

   [quote][b]

cookwithgas

Joined: 06 Nov 2007
Posts: 159

Posted: Mon Feb 11, 2008 4:16 pm Post subject: Re: larger trim tab

Hey John:



Been there, done that and it flies.  I installed the small one, then took it off and made the larger one and left my actuator in the same place.  It works well.  Here's a picture:



http://www.cooknwithgas.com/4_21_05_TrimTab.JPG



The original trim tab is sitting on top of the elevator.  It didn't take that long to make all the pieces and re-do it.  



Scott Laughlin

www.cooknwithgas.com

planecrazydld(at)yahoo.co
Guest

Posted: Mon Feb 11, 2008 5:03 pm Post subject: larger trim tab

note that I was planning on using the manual tab control that the Sonex people sell and not the electric servo motor type supplied. I was afraid that the increased mass aft of the hinge line on the unbalanced surface would push the flutter limits...



David Downey <planecrazydld(at)yahoo.com> wrote:[quote] back when I was still working on the XL I was planning to simply build the half span tab into both halves of the elevator. It looked to me like the weight penalty would be about 6-8 ounces and if the authority was not needed the tab deflection would have simply been less than with a single tab...



Bill Berle <victorbravo(at)sbcglobal.net> wrote:[quote] --> Zenith-List message posted by: Bill Berle  



Trim tabs can cause flutter if they are not done correctly and securely. 

On a super-light structure like a Zenair aircraft elevator, elevator 

flutter would be an INSTANT catastrophic situation.



This is one of those things where something that doesn't seem like a big 

safety risk can cause a safety risk.



Larger trim tabs can be done safely for sure, don't be immediately 

afraid of it, but  you just have more to think about and more things to 

do to make it safer. And you DO have to check with ZAC because they know 

how large/heavy/flexible of a trim tab is OK and what is too much.



john butterfield wrote:

[quote] --> Zenith-List message posted by: john butterfield 



 hi guys.

 i have the small trim tab on my elevator and was

 wondering if the new (larger) trim tabs connects to

 the old (small tab) trim motor arm.  if it will, i

 [quote][b]

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Mon Feb 11, 2008 5:12 pm Post subject: Re: larger trim tab

Flutter won't be an issue.

 	  planecrazydld(at)yahoo.co wrote: 	
		  note that I was planning on using the manual tab control that the Sonex people sell and not the electric servo motor type supplied. I was afraid that the increased mass aft of the hinge line on the unbalanced surface would push the flutter limits...

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

planecrazydld(at)yahoo.co
Guest

Posted: Mon Feb 11, 2008 6:12 pm Post subject: larger trim tab

Hey Gig;



I mean absolutely no disrespect but I have spent 35 years in the aircraft design, development, and test world. Flutter can never be ruled out on any surface with any degree of freedom - especially unbalanced or underbalanced hinged surfaces. In those cases adding weight aft of the hinge is a definite recipe for "new" issues to rear their heads.



I would agree with you to the extent that I have seen no evidence of a susceptibility on the XL though.



Gig Giacona <wr.giacona(at)suddenlink.net> wrote:[quote] --> Zenith-List message posted by: "Gig Giacona" 



Flutter won't be an issue.



planecrazydld(at)yahoo.co wrote:

[quote] note that I was planning on using the manual tab control that the Sonex people sell and not the electric servo motor type supplied. I was afraid that the       Be a better friend, newshound, and  [quote][b]

dougsnash(at)yahoo.com
Guest

Posted: Tue Feb 12, 2008 8:11 am Post subject: larger trim tab

Remeber David, the servo is mounted fairly close to

the hinge line and only the rod goes out to the tab. 

I would think a trim system that runs cables from the

cockpit would be heavier than the electric unit from

Ray Allen.



Take these comments with a grain of salt though since

I am a 701 builder and only dreaming of an XL in the

future.



Doug MacDonald

CH-701 Scratch Builder

NW Ontario, Canada



--- David Downey <planecrazydld(at)yahoo.com> wrote:



 	  Quote: 	
		   Hey Gig;

 

 I mean absolutely no disrespect but I have spent 35

 years in the aircraft design, development, and test

 world. Flutter can never be ruled out on any surface

 with any degree of freedom - especially unbalanced

 or underbalanced hinged surfaces. In those cases

 adding weight aft of the hinge is a definite recipe

 for "new" issues to rear their heads.

 

 I would agree with you to the extent that I have

 seen no evidence of a susceptibility on the XL

 though.


	


Looking for last minute shopping deals?

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Tue Feb 12, 2008 11:06 am Post subject: Re: larger trim tab

Not an aircraft design engineer but I have been flying about 30 years and in the majority of aircraft I have flown there has been some sort of unbalanced trim system back on the elevator.



I'd date say that the RAC servo probably weighs less than the extra AL, hinge and rivets that make up the trim tab to begin with and since I have the original smaller tab it probably weighs less than the larger tab without the servo.



Let's also keep in mind that CH designed that servo and into the system in the first place.



And finally there are a metric butt load of 601s and 701s out there and not a word about elevator flutter caused by the weight of the servo or for any other reason.

 	  planecrazydld(at)yahoo.co wrote: 	
		  Hey Gig;



I mean absolutely no disrespect but I have spent 35 years in the aircraft design, development, and test world. Flutter can never be ruled out on any surface with any degree of freedom - especially unbalanced or underbalanced hinged surfaces. In those cases adding weight aft of the hinge is a definite recipe for "new" issues to rear their heads.



I would agree with you to the extent that I have seen no evidence of a susceptibility on the XL though.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

planecrazydld(at)yahoo.co
Guest

Posted: Tue Feb 12, 2008 2:20 pm Post subject: larger trim tab

well taken Gig.



Gig Giacona <wr.giacona(at)suddenlink.net> wrote:[quote] --> Zenith-List message posted by: "Gig Giacona" 



Not an aircraft design engineer but I have been flying about 30 years and in the majority of aircraft I have flown there has been some sort of unbalanced trim system back on the elevator.



I'd date say that the RAC servo probably weighs less than the extra AL, hinge and rivets that make up the trim tab to begin with and since I have the original smaller tab it probably weighs less than the larger tab without the servo.



Let's also keep in mind that CH designed that servo and into the system in the first place.



And finally there are a metric butt load of 601s and 701s out there and not a word about elevator flutter caused by the weight of the servo or for any other [quote][b]

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