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When is balance balanced?

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Mike Welch

Joined: 13 Feb 2011
Posts: 272

Posted: Sat Apr 23, 2011 2:25 pm Post subject: When is balance balanced?

Kolb guys,

  

   In consideration of Bob Green, I'm going to do my part to bring up a question 

 to the Kolb list members;

  

   I'm in the middle of fabricating balance rods for my MkIII's elevator(s).  I have the

 "4 sided" horizontal stabilizers like some Xtras have, with the outer dimension close

 to 11" or so (see photo).

   The balance rods consist of 3/4" chromoly tubing, with a 3" welded "T" stub that inserts 

 into the elevator's main tube and will be riveted.  At the moment, the rods are about 12" long,

 and run the full length alongside the hor. stabs.

  

   Here's the dilemma!!  Even when I slide in 7" long solid steel weight rods into the ends of the

 the balance rod tubes, this still doesn't come close to "blanacing" the elevators.  In fact, it takes

 quite a bit more solid steel rod, hung out on the end of the balance tubes to get it to 'act' level.

  

   While I'm monkeying around with various weights, in occurs to me (duh!) that if I want to 

 'balance' the elevators......I'm going to need close to the full weight of the elevators!!   I can't

 say that I like this!!  In order to achieve a true and complete elevator balance, I will need to

 add a fair amount of steel rod!   (photos on request)

  

   Here's my question;  For you guys that have the elevator balance rods, did you really add 

 so much weight that the elevator was truely balanced, or did you possibly just add 'some'

 weight, that would act like a reasonably decent counter-balance? 

  

   I know another way to solve my problem would be to lengthen the balance rods, say...from their

 present 12" length (which doens't work at the moment, unless they were maybe filled with lead),

 to extend out in front of the hor. stabs 6", to something like 18" overall.  I sure DO NOT like this

 solution, since, IMO, it looks like the balance rods were a complete afterthought (which they were).

 Still....I don't want them to look dopey!!

  

   What did you guys do to balance your elevator?  Nothing?  .....Some weight, but not a complete 

 balance?   Or did you just add enough rod length to keep the weight low?  

  

   I'm kind of at a loss at the moment, any thoughts??????

  

 Mike Welch

 very unbalanced, quite possibly unstable, too.

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rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Sat Apr 23, 2011 3:43 pm Post subject: When is balance balanced?

Mike, Your elevators have a center of mass that is a certain distance from the hinge centerline. The two together create a moment and an arm. To balance them you must have an equivalent moment and arm on the other side of the hinge line.  The problem with using a solid rod is that the balancing mass isn't concentrated enough, i.e too much of the mass ends up too close to the hinge line. This is the standard Kolb solution for the aileron counterbalances. I have them and they work great, BUT if I were to do it over again, I would use a hollow tube and either stuff the balance end with lead shot in epoxy, or solder a brass weight to the end of the tube. The idea is to concentrate the most mass on the shortest applicable moment arm to balance the control surface.

 As to whether to do a partial or a complete balance, I'd go for the complete balance if only because it's the same amount of work. The problem with doing a partial balance is that you could inadvertently hit a hamonic of the flutter frequency that could make the situation worse instead of better.

 MHO with Beauford's caveat.

Rick Girard

 

On Sat, Apr 23, 2011 at 5:19 PM, Mike Welch <mdnanwelch7(at)hotmail.com (mdnanwelch7(at)hotmail.com)> wrote:

 	  Quote: 	
		         Kolb guys,

  

   In consideration of Bob Green, I'm going to do my part to bring up a question 

 to the Kolb list members;

  

   I'm in the middle of fabricating balance rods for my MkIII's elevator(s).  I have the

 "4 sided" horizontal stabilizers like some Xtras have, with the outer dimension close

 to 11" or so (see photo).

   The balance rods consist of 3/4" chromoly tubing, with a 3" welded "T" stub that inserts 

 into the elevator's main tube and will be riveted.  At the moment, the rods are about 12" long,

 and run the full length alongside the hor. stabs.

  

   Here's the dilemma!!  Even when I slide in 7" long solid steel weight rods into the ends of the

 the balance rod tubes, this still doesn't come close to "blanacing" the elevators.  In fact, it takes

 quite a bit more solid steel rod, hung out on the end of the balance tubes to get it to 'act' level.

  

   While I'm monkeying around with various weights, in occurs to me (duh!) that if I want to 

 'balance' the elevators......I'm going to need close to the full weight of the elevators!!   I can't

 say that I like this!!  In order to achieve a true and complete elevator balance, I will need to

 add a fair amount of steel rod!   (photos on request)

  

   Here's my question;  For you guys that have the elevator balance rods, did you really add 

 so much weight that the elevator was truely balanced, or did you possibly just add 'some'

 weight, that would act like a reasonably decent counter-balance? 

  

   I know another way to solve my problem would be to lengthen the balance rods, say...from their

 present 12" length (which doens't work at the moment, unless they were maybe filled with lead),

 to extend out in front of the hor. stabs 6", to something like 18" overall.  I sure DO NOT like this

 solution, since, IMO, it looks like the balance rods were a complete afterthought (which they were).

 Still....I don't want them to look dopey!!

  

   What did you guys do to balance your elevator?  Nothing?  .....Some weight, but not a complete 

 balance?   Or did you just add enough rod length to keep the weight low?  

  

   I'm kind of at a loss at the moment, any thoughts??????

  

 Mike Welch

 very unbalanced, quite possibly unstable, too.

  

 		 	   		  

 	


-- 

Zulu Delta

Mk IIIC

Thanks, Homer GBYM

It isn't necessary to have relatives in Kansas City in order to be unhappy.

    - Groucho Marx



 

  [quote][b]

_________________
The smallest miracle right in front of you is enough to make you happy....

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sat Apr 23, 2011 3:50 pm Post subject: When is balance balanced?

What did you guys do to balance your elevator?  Nothing?  .....Some 

weight, but not a complete

balance?   Or did you just add enough rod length to keep the weight low?



  I'm kind of at a loss at the moment, any thoughts??????



Mike Welch

very unbalanced, quite possibly unstable, too.



Mike W/Gang:



Why are you trying to balance your elevators?



Is there a flutter problem with Kolb elevators?



john h

mkIII

Titus, Alabama

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Mike Welch

Joined: 13 Feb 2011
Posts: 272

Posted: Sat Apr 23, 2011 6:24 pm Post subject: When is balance balanced?

 	  Quote: 	
		   Is there a flutter problem with Kolb elevators?

 

 john h

 mkIII

 Titus, Alabama

 
	


  John,

 

  I 'thought' there was...or could be.  I was under the impression all control

surfaces needed to be balanced.  I guess not...

 

  I got an 'off-list' response from the list's most distinguished pilot, explaining

that many (all?) MkIII's don't have balanced elevators.  OH!!  I didn't know that.

I thought at least some of them were. 

 

  I do recall seeing somewhere where one Kolb builder used a balance rod

that was attached to the top of the rudder.  Although I could not remember any

elevator balancing systems, I kinda thought a few guys did balance theirs

Kip

Joined: 13 Jul 2009
Posts: 51

Posted: Sat Apr 23, 2011 6:51 pm Post subject: Re: When is balance balanced?

I thought that I was the most distinguished pilot...  



Never had elevator flutter and any flutter in 450 hours.



Balanced ailerons.

_________________
2000 Firestar II
R503 DCDI
VLS 750

2010 Waiex
Jabiru 3300

2020 Pitts Special S-1C

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sat Apr 23, 2011 7:05 pm Post subject: When is balance balanced?

I thought that I was the most distinguished pilot... [Wink]





Kip/Gang:



In my book you are.



john h

mkIII

hauck's holler, alabama

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Sun Apr 24, 2011 4:13 am Post subject: Re: When is balance balanced?

 	  Mike Welch wrote: 	
		  

  

  I do recall seeing somewhere where one Kolb builder used a balance rod

that was attached to the top of the rudder. 	




That would probably be me. Stops the "Rudder Pedal Shuffle." But I am not aware of any problem with the elevators. Sounds to me like fixing a problem that doesn't exist.



Sort of like Greenhouse Gases and Global Warming... Next thing you know some twit will be trying to save the polar bears from dihydrogen monoxide...



Richard Pike

MKIII N420P (420ldPoops)

Dan Breitigam

Joined: 06 Apr 2011
Posts: 16

Posted: Sun Apr 24, 2011 12:58 pm Post subject: Re: When is balance balanced?

Dan the newbie here. So I've got this original Twinstar which I plan to fly with no windshield or fairing. Â It has full length ailerons. Â Should I balance them? Â I'm not quite ready to deploy my brand new Second Chantz chute yet. 



Dan

Mike Welch

Joined: 13 Feb 2011
Posts: 272

Posted: Sun Apr 24, 2011 3:46 pm Post subject: When is balance balanced?

Bro Pike,

  

   Yeah, I knew it was you that had the rudder balance rod, I just couldn't find your 

 pictures of it to confirm.

  

   Dihydrogen monoxide is especially troubling when it is coming at you in solid form,

  the shape of a small compact sphere, thrown by a 12 year old grandkid!

  

    Re: greenhouse gases, and global warming, it seems to me.................nevermind, 

 I'll just leave this one alone.  he he

  

 Mike Welch  

 

 > Subject: Re: When is balance balanced?

 	  Quote: 	
		   From: richard(at)bcchapel.org

 Date: Sun, 24 Apr 2011 05:13:52 -0700

 To: kolb-list(at)matronics.com

 

 --> Kolb-List message posted by: "Richard Pike" <richard(at)bcchapel.org>

 

 

 Mike Welch wrote:

 > 

 > 

 > I do recall seeing somewhere where one Kolb builder used a balance rod

 > that was attached to the top of the rudder. 

 

 

 That would probably be me. Stops the "Rudder Pedal Shuffle." But I am not aware of any problem with the elevators. Sounds to me like fixing a problem that doesn't exist.

 

 Sort of like Greenhouse Gases and Global Warming... Next thing you know some twit will be trying to save the polar bears from dihydrogen monoxide...

 

 Richard Pike

 MKIII N420P (420ldPoops)

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=337974#337974

 

 

 

 

 

 

&======================
	


&gt============

[quote] 

 

 

 		 	   		     	  Quote: 	
		  [b]

Herb Graff

Joined: 21 Sep 2009
Posts: 12

Posted: Sun Apr 24, 2011 3:47 pm Post subject: When is balance balanced?

Hi Dan,

  

 As a general safety principle, all control surfaces should be balanced. Go  to your local airport and check  the aircraft there, all having  balanced controls (at least all the commercial ones). If you are in a quandary  whether to balance, you actually know already what the safe insurance is. I  seem to recall both aileron as well rudder flutter instances reported  for the Mark III, in each case unbalanced. One pilot reported he could take out  incipient rudder flutter by pressing hard on both rudder pedals. Which  brings us, as far as I know of, to no reported instances of elevator flutter.  Reason for that may be the connected weight/inertia of tight(er) cables to  the control column all leading to a dampening of an incipient  oscillation. 

  

 Herb Graff

 Mark III, N246KT

  

  

  

  

  In a message dated 4/24/2011 5:01:17 P.M. Eastern Daylight Time,  dbrtgm(at)me.com writes:

  	  Quote: 	
		  

Dan    the newbie here. So I've got this original Twinstar which I plan to fly with    no windshield or fairing. Â It has full length ailerons. Â Should I    balance them? Â I'm not quite ready to deploy my brand new Second Chantz    chute yet. 



Dan



	


 [quote][b]

Mike Welch

Joined: 13 Feb 2011
Posts: 272

Posted: Sun Apr 24, 2011 3:48 pm Post subject: When is balance balanced?

 

 > Dan the newbie here. So I've got this original Twinstar which I plan to fly with no windshield or fairing. Â It has full length ailerons. Â Should I balance them? Â I'm not quite ready to deploy my brand new Second Chantz chute yet. 

 	  Quote: 	
		   

 Dan


	


  

 Hi Dan,

  

   I am NOT an expert (although there are some pretty good ones on this list), but

 one thing I have heard is 'YES', balance your ailerons.

  

   I would suggest you get ahold of Travis or Bryan at Kolb Aircraft, and see what they

 can do for you.

  

 Mike Welch

 MkIII (in the process of installing aileron blances)

 

  		 	   		    [quote][b]

Dan Breitigam

Joined: 06 Apr 2011
Posts: 16

Posted: Sun Apr 24, 2011 6:51 pm Post subject: When is balance balanced?

Dan the newbie here. So I've got this original Twinstar which I plan to fly with no windshield or fairing.  It has full length ailerons.  Should I balance them?  I'm not quite ready to deploy my brand new Second Chantz chute yet. 



Dan

_________________
Dan Breitigam
Kolb Mk III Xtra
Geo Metro 1.3L
Chattanooga

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