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Aileron flutter and Tail-wag

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beauford

Joined: 25 Apr 2007
Posts: 127
Location: Brandon, FL

Posted: Fri Sep 24, 2010 12:37 pm Post subject: Aileron flutter and Tail-wag

Brother Pike:



The Kolb rudder oscillation- tail wag phenomenon has been mentioned on the

list several times in the past... True to form, take my tootsies off the

pedals for five seconds or so, and the Kleenex Machine will invariably

launch into an increasing amplitude snake dance.   



Since Beauford is not into self abuse (beyond matrimony) and I have a strong

recollection of how few lil' ol pop-rivets are holding the arse end of the

thing in association with the front end,  I never let it go more than three

or four seconds before putting the feet back on the pedals to stop it before

it gets really wild.



In my aerodynamic ignorance, have always assumed this to be some combination

of rudder mass balance issue and interaction with the propwash vortex.

Since it is easily arrested and Kolbs have no history of shedding tails or

boom failure, have never been overly concerned about it...but am curious as

to whether any of the learned brethren on the List know exactly why this

happens to Kolbs and what practical fix might solve it without a redesign of

the vertical tail surfaces...



Anybody?  



Or from another angle... Does anyone have a Kolb that does NOT exhibit this

behavior...?



Curious Beauford

FF-076, N173BW

Brandon, FL




Then there was the matter of the rudder flutter, take your feet off the

rudder pedals and they would start to shuffle and the tail would start to

wig-wag..



Richard Pike

MKIII N420P (420ldPoops)

donaho1(at)verizon.net
Guest

Posted: Fri Sep 24, 2010 1:01 pm Post subject: Aileron flutter and tail-wag

My FSII kit came with the aileron counter weights, so I have never 

experienced that flutter problem. I don`t fly with my feet completely 

off the rudder peddles, but I do fly with very little pressure on 

them. I have never felt them start to flutter. I fly around 60 mph 

according to the GPS. Perhaps that isn`t fast enough to induce 

flutter. Flutterless is good, so I`ll leave everything as it is. Lanny N598LF

John Hauck

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

Posted: Fri Sep 24, 2010 1:27 pm Post subject: Aileron flutter and Tail-wag

> In my aerodynamic ignorance, have always assumed this to be some 

combination

 	  Quote: 	
		   of rudder mass balance issue and interaction with the propwash vortex.


	


 	  Quote: 	
		  what practical fix might solve it without a redesign of

 the vertical tail surfaces...


	


 	  Quote: 	
		   Or from another angle... Does anyone have a Kolb that does NOT exhibit 

 this

 behavior...?



 Curious Beauford


	


Beauford/Gang:



That is also my assumption.



My initial fix was heavy feet.



I finally came up with a bright idea, double rudder pedal springs applied 

about the same pressure as heavy feet.  Works great, can fly with feet on 

the deck and no tail wag.



I have flown a couple Kolbs that did not tail wag, however, I think it is a 

Kolb characteristic that no one, that I know of, has died of.



Anybody know of a Kolb that crashed because of tail wag???



john h

mkIII

7 miles south of Burns Junction, OR

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

zeprep251(at)aol.com
Guest

Posted: Fri Sep 24, 2010 1:27 pm Post subject: Aileron flutter and Tail-wag

Beauford,

 My MK-3 will do the wag in it's normal configuration,but adding a second set of springs to the rudder cables has all but eliminated it.Brother Pike is the only Kolbster, ( that I know of), that has treated his aircraft with a counter balance and solved the issue.But he now has to deal with birds perching on the balance rod and crapping on the boom tube.A small price to pay for aerodynamic bliss.

 G.Aman Mk-3 C Jabiru 2200A 590 hrs.

  

     

  

    

     

  

     

  

    --

Ralph B

Joined: 14 Apr 2007
Posts: 367
Location: Mound Minnesota

Posted: Fri Sep 24, 2010 1:59 pm Post subject: Re: Aileron flutter and Tail-wag

My Firestar will do the tail wag with the feet off the rudder pedals only if hit by a strong thermal, otherwise there is none. I can make it quit by bringing it up into a stall. The Kolbra does not have this problem.



Ralph

_________________
Ralph B

Kolb Kolbra 912uls
N20386
550 hours

beauford

Joined: 25 Apr 2007
Posts: 127
Location: Brandon, FL

Posted: Fri Sep 24, 2010 4:10 pm Post subject: Aileron flutter and Tail-wag

John:



Already have the double springs installed, Sir.... not for the wag, but just

because of a general distrust

of springs in general...tail wags anyway...



Most things I mess with either suffer from abrupt unanticipated drop or

directional instability...

So this is no big deal... But would still like to see a picture of the

Reverend Mr. Pike's counterweight

contrivance fer rudders...    Are ye out there, Richard?



Do not archive



Beauford

FF-076

Brandon, FL

--------------------------




I finally came up with a bright idea, double rudder pedal springs applied 

about the same pressure as heavy feet.  Works great, can fly with feet on 

the deck and no tail wag.



john h

mkIII

7 miles south of Burns Junction, OR

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Sat Sep 25, 2010 2:34 am Post subject: Re: Aileron flutter and Tail-wag

Re:  ... Does anyone have a Kolb that does NOT exhibit this 

behavior...? 



Strangely enough, my Slingshot does not wag its tail without feet on rudder pedals, at least at my normal 65% power cruise of 80mph. Never tried lifting the feet at higher speeds nor lower speeds. I have only a single spring on each rudder pedal. BTW, my ailerons do have the counterbalances and I have never experienced flutter at any speed up to 100 mph, which is as fast as I've flown it.



Not directly related but may be of interest to some:

Funny thing happened since I straightened my gear legs after a bending incident early this summer. Before I unbent my gear legs, the SS would not hold a course for more than a few seconds with my feet off the pedals. After the unbending, in calm air my SS will track straight and true in calm air for quite a while with my feet off the pedals. I'm guessing my unbending job left them a little different aerodynamically than before they were bent. Can't complain about this unintended consequence.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

dsmald(at)aol.com
Guest

Posted: Sat Sep 25, 2010 5:40 am Post subject: Aileron flutter and Tail-wag

Curious Beauford,

  

 I have never had any flutter on any surfaces on my FS1 even at VNE. (other than my fabric gap seal which needs new strips of loop velcro..!)

  No counter weights, extra springs, trim tabs, etc on any control surfaces. I have long ailerons with 5 rib wings and I can fly without my feet on the pedals. I can actually control the plane to a degree at 50 mph by weight shift by shifting my 190# side to side and also climb / descend by pulling my feet back and stretching them forward. 

  I guess I got lucky building it?? Sweet flying plane.

  Fly safe!

  Darren, FS1, 40hp Hirth, Central MI.

  

     >>>>>>>>>>>>>>>>>>>>>>>>>>

  

     	  Quote: 	
		  >>Time: 01:37:44 PM PST US

From: "Beauford " <beauford173(at)verizon.net (beauford173(at)verizon.net)>

Subject: Re: Aileron flutter and Tail-wag

 	  Quote: 	
		  >Brother Pike:


	


 	  Quote: 	
		  >The Kolb rudder oscillation- tail wag phenomenon has been mentioned on the

list several times in the past... True to form, take my tootsies off the
	


pedals for five seconds or so, and the Kleenex Machine will invariably

launch into an increasing amplitude snake dance.   



Since Beauford is not into self abuse (beyond matrimony) and I have a strong

recollection of how few lil' ol pop-rivets are holding the arse end of the

thing in association with the front end,  I never let it go more than three

or four seconds before putting the feet back on the pedals to stop it before

it gets really wild.



In my aerodynamic ignorance, have always assumed this to be some combination

of rudder mass balance issue and interaction with the propwash vortex.

Since it is easily arrested and Kolbs have no history of shedding tails or

boom failure, have never been overly concerned about it...but am curious as

to whether any of the learned brethren on the List know exactly why this

happens to Kolbs and what practical fix might solve it without a redesign of

the vertical tail surfaces...



Anybody?  



Or from another angle... Does anyone have a Kolb that does NOT exhibit this

behavior...?



Curious Beauford

FF-076, N173BW

Brandon, FL

	


     

  

     

  

    --

frank.goodnight(at)att.ne
Guest

Posted: Sat Sep 25, 2010 5:53 am Post subject: Aileron flutter and Tail-wag

Beauford,

  

 I sometimes fly my firestar 2 for 10 or 15 min at a time with my feet off the ruder -sometimes with them ( my feet)

 hanging over the side, no cover on the cage. I really can't tell any difference --feet on or feet off-except 

 I'll drift off heading after a min or so . 



 

 Frank Goodnight

 Firestar 2 HKS

 Brownsville , TX

   

 From: Beauford <beauford173(at)verizon.net>

To: kolb-list(at)matronics.com

Sent: Fri, September 24, 2010 3:29:25 PM

Subject: Re: Aileron flutter and Tail-wag



--> Kolb-List message posted by: "Beauford " <beauford173(at)verizon.net (beauford173(at)verizon.net)>



Brother Pike:



The Kolb rudder oscillation- tail wag phenomenon has been mentioned on the

list several times in the past... True to form, take my tootsies off the

pedals for five seconds or so, and the Kleenex Machine will invariably

launch into an increasing amplitude snake dance.  



Since Beauford is not into self  abuse (beyond matrimony) and I have a strong

recollection of how few lil' ol pop-rivets are holding the arse end of the

thing in association with the front end,  I never let it go more than three

or four seconds before putting the feet back on the pedals to stop it before

it gets really wild.



In my aerodynamic ignorance, have always assumed this to be some combination

of rudder mass balance issue and interaction with the propwash vortex.

Since it is easily arrested and Kolbs have no history of shedding tails or

boom failure, have never been overly concerned about it...but am curious as

to whether any of the learned brethren on the List know exactly why this

happens to Kolbs and what practical fix might solve it without a redesign of

the vertical tail surfaces...



Anybody?  



Or from another angle... Does anyone have a Kolb that does NOT exhibit this

behavior...?



Curious  Beauford

FF-076, N173BW

Brandon, FL



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

Then there was the matter of the rudder flutter, take your feet off the

rudder pedals and they would start to shuffle and the tail would start to

wig-wag..



Richard Pike

MKIII N420P (420ldPoops)



-=                    &==

 [quote][b]

John Hauck

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

Posted: Sat Sep 25, 2010 7:27 am Post subject: Aileron flutter and Tail-wag

Darren/Gang:

  

 Be aware there are other triggers for flutter than  high air speeds.  Certain turbulence will set it off at much lower  airspeeds in a flash.

  

 john h

 mkIII

  

 [quote]    

I have never had any flutter on any surfaces on my    FS1 even at VNE. 

    

    Darren, FS1, 40hp Hirth,    Central MI.



    

[b]

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

Richard Pike

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

Posted: Sat Sep 25, 2010 8:35 am Post subject: Re: Aileron flutter and Tail-wag

[quote="beauford"]John:



Already have the double springs installed, Sir.... not for the wag, but just

because of a general distrust

of springs in general...tail wags anyway...



Most things I mess with either suffer from abrupt unanticipated drop or

directional instability...

So this is no big deal... But would still like to see a picture of the

Reverend Mr. Pike's counterweight

contrivance fer rudders...    Are ye out there, Richard?



Do not archive



Beauford

FF-076

Brandon, FL

--------------------------



Here's the bird poop perch - what's odd is that I don't get much bird poop below it, but the left side of the horizontal stab constantly gets littered with some sort of little black droppings. Never have figured out exactly what sort of poop it is (I am trying not to get too proficient in that sort of thing) or why it is only at that one place. At least it doesn't stick, the prop blows it away.

http://www.bcchapel.org/pages/0003/pg6.htm



Richard Pike

MKIII N420P (420ldPoops)

mdnanwelch7(at)hotmail.co
Guest

Posted: Sat Sep 25, 2010 10:06 am Post subject: Aileron flutter and Tail-wag

> Here's the bird poop perch - what's odd is that I don't get much bird poop below it, but the left side of the horizontal stab constantly gets littered with some sort of little black droppings. > Richard Pike

 	  Quote: 	
		   MKIII N420P (420ldPoops)


	


 Bro. Richard,

  

   If you don't want any flying creatures landing on your rudder counterbalance arm, you 

 might consider building a little contraption I saw once.

  

   If you make a little device that suspends a couple of loose strings above the length of the

 balance arm, birds can't quite land on it, so they pass it up.  Either loose wire or string

 will do, maybe one or two strands is all you need.

  

   With a floppy string in the way, it interferes with the bird being able to get a grip on the 

 counterbalance arm.  Keep the string sort of close, maybe about 1/4 to 1/2" and the birds 

 can't wrap their feet around the string and the arm.

   You could probably throw something together in about 10 minutes.  You might consider

 a clothes pins or weak finger clamps.  (see attached drawing for an idea of what 

 I'm getting at)

  

   Just a thought...

  

 Mike Welch

bird_deterant.JPG

Description:

Filesize:

19.66 KB

Viewed:

13309 Time(s)

cedavis

Joined: 05 Jun 2006
Posts: 23
Location: Malvern, PA

Posted: Mon Sep 27, 2010 4:41 am Post subject: Aileron flutter and Tail-wag

Been offline for a few days, but my Firefly does not exhibit "tail wagging",  In fact, I have flown it "sans-feet" for 20 minutes at a time, just to change leg position on a cross country.    Only needed to put the feet back on the pedals to change position again...the plane is quite happy with out them.

 

Chuck Davis

Firelfy

N7057K 

Smoketown, PA



 Time: 01:37:44 PM PST US

 From: "Beauford " <beauford173(at)verizon.net (beauford173(at)verizon.net)>

 Subject: Re: Aileron flutter and Tail-wag

 

 

 Brother Pike:

 

 The Kolb rudder oscillation- tail wag phenomenon has been mentioned on the

 list several times in the past... True to form, take my tootsies off the

 pedals for five seconds or so, and the Kleenex Machine will invariably

 launch into an increasing amplitude snake dance.

 

 Since Beauford is not into self abuse (beyond matrimony) and I have a strong

 recollection of how few lil' ol pop-rivets are holding the arse end of the

 thing in association with the front end,  I never let it go more than three

 or four seconds before putting the feet back on the pedals to stop it before

 it gets really wild.

 

 In my aerodynamic ignorance, have always assumed this to be some combination

 of rudder mass balance issue and interaction with the propwash vortex.

 Since it is easily arrested and Kolbs have no history of shedding tails or

 boom failure, have never been overly concerned about it...but am curious as

 to whether any of the learned brethren on the List know exactly why this

 happens to Kolbs and what practical fix might solve it without a redesign of

 the vertical tail surfaces...

 

 Anybody?

 

 Or from another angle... Does anyone have a Kolb that does NOT exhibit this

 behavior...?

 

 Curious Beauford

 FF-076, N173BW

 Brandon, FL

 

 

 

 Then there was the matter of the rudder flutter, take your feet off the

 rudder pedals and they would start to shuffle and the tail would start to

 wig-wag..

 

 Richard Pike

 MKIII N420P (420ldPoops)

#avg_ls_inline_popup {  position:absolute;  z-index:9999;  padding: 0px 0px;  margin-left: 0px;  margin-top: 0px;  width: 240px;  overflow: hidden;  word-wrap: break-word;  color: black;  font-size: 10px;  text-align: left;  line-height: 13px;}  [quote][b]

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Mon Sep 27, 2010 10:06 am Post subject: Re: Aileron flutter and Tail-wag

My Kolb MK-III Xtra does not have any type of rudder flutter, or tendency to tail wag.   When my wife is flying, she keeps her feet on the floor most of the time, my Kolb cruises along happily for an hour without anyone ever touching the rudder pedals.  Even in turbulence my wife uses the ailerons only, she never touches the rudder on a cross country because there is no need to.  



I have a counterweight on my rudder,, just like the ailerons have.   Kolb also put an extra bell crank on the rudder cables of the MK III Xtra, which keeps the rudder cables tensioned just like the elevator.  Ever wondered why the elevator never flutters on a Kolb and the rudder does  ???  Its those tensioned cables on the elevator that adds mass and resistance to quick movement and flutter.  If you do not believe this, just loosen your elevator cables so that they jsut hang there loose, and go fly and see how long it takes for that elevator to flutter    Joking aside, NEVER try this, because you probably would not live long enough to get on the ground and report your findings !!!



So the easiest and best solution would seem to be a counterweight on the rudder, just like your ailerons have.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

pj.ladd(at)btinternet.com
Guest

Posted: Mon Sep 27, 2010 11:01 am Post subject: Aileron flutter and Tail-wag

My Kolb MK-III Xtra does not have any type of rudder flutter, or tendency to 

tail wag. >>



Neither does mine. I have the counterweights fitted AS PER THE PLANS. They 

are ON THE PLANS FOR A PURPOSE.

Why do builders try to second guess Homer who quite obviously knew what he 

was doing? If he specified counterweights then for crying out loud Fit 

counterweights.



On another point. Not using the rudder.Although I agree that you can fly 

happily in a straight line without the rudder, changing course or using the 

ailerons necessitates using rudder properly.

I learned to fly in gliders where it is important always to present the 

minimum frontal area to the airflow  because drag represents loss of height 

so I never move the stick with automatically applying some rudder. But 

beyong that. Applying bank WITHOUT rudder just makes it very, very hard to 

get your wing down. With rudder its a doddle. Try appling bank and then 

reversing it without rudder. It takes forever and needs muscles like Popeye. 

With rudder she slips around easily, as she was designed to do. Use the 

rudder.Its there for a reason. Why fight it.?

There are no points for not flying properly.



Pat

John Hauck

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

Posted: Mon Sep 27, 2010 3:25 pm Post subject: Aileron flutter and Tail-wag

> So the easiest and best solution would seem to be a counterweight on the 

rudder, just like your ailerons have.

 	  Quote: 	
		  

 Mike


	




Mike B/Gang:



I don't think your solution is the easiest or the best.



Took me a couple minutes to add two additional rudder pedal springs that 

fixed my problem.



john h

mkIII

Rock House, OR

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

Jimmy Young

Joined: 24 Nov 2007
Posts: 182
Location: Missouri City, TX

Posted: Mon Sep 27, 2010 5:37 pm Post subject: Re: Aileron flutter and Tail-wag

My FS II has no tail wag issues. I flew over 3 hrs yesterday, mid-day, with lots of thermals & gusty conditions. Looked back at the tail numerous times and it just sits there doing it's job, no wagging around. I dropped in to visit with Robert Laird and we discussed the issue, he said his MK III has no tail wag going on either. I do have very tight tailwires, and have seen some Kolbs with wires that are fairly loose. Maybe that could be a contributing cause.

_________________
Jimmy Young
Missouri City, TX
Kolb FS II/HKS 700

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