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jconnell(at)fmwildblue.co
Guest

Posted: Mon Apr 13, 2009 6:56 am Post subject: Kitfox Model II flight behavior

Gentlemen,



I've been flying my Kitfox-II for about 12 years.   An item in the May issue of "Flying" magazine is prompting this note.  One  paragraph in an article called "Aftermath" by Pete Garrison states the  following:



"I have very limited experience in LSAs, but one very popular  model that I have flown had surprising flight characteristics, including a  rudder so whimsical that it would remain at either stop, fully deflected, while  the pilot's feet were flat on the floor and the airplane flew merrily along in a  gigantic sideslip. This is the kind of behavior that one associates with the  First World War, not the 21st century."

  

 My Kitfox-II exhibits the exact characteristic!  If my feet are on the  floor, I will get a very strong adverse yaw just by moving the wings a  bit.  If I look in the rearview mirror I can see the rudder is fully  deflected.  It's as if the short fuselage and the small vertical stabilizer  are insufficient to prevent yaw in straight flight.  If I remember, the  Model-III and above have a much larger vertical stabilizer (with an  airfoil) and rudder assembly.  The Kitfox has long wings relative to  fuselage.

  

 Is anyone else experiencing this condition?  I'm thinking of adding  some sort of centering springs to keep the rudder centered in straight and level  flight.  I've even toyed with the idea of replacing the rudder with a  larger later model...

  

  

 Joe Connell

 Kitfox-II N62JK

   [quote][b]

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Mon Apr 13, 2009 7:11 am Post subject: Re: Kitfox Model II flight behavior

The "very strong adverse yaw" comes from the flaperon mixer design.  While a larger vertical stab will help the issue, the real bottom line is the flaperons travel 2X more down than they do up.  The down flaperon creates more drag and pull you to that side ( you roll right and the nose goes to the left).  New mixers mods, will give you 2X more up than down and the majority of the adverse yaw goes away.



When setting my large models up for competition, it takes atleast 35 or 40 flights to get all the bad habits mixed out of the plane.  One of the biggest issues is getting aileron travel dialed in so you perfectly axial rolls.  This generally ends up have 2 to 2.5 times more up travel than down.



You can get the model IV mixer system from KF and retro it to your plane, but if you have been flying it this way for 12 years I think you have a handle on it.



Personally I think it makes you a better pilot because it forces you to use your feet..... alot.

_________________
DO NOT ARCHIVE
Leonard Perry aka SNAKE
Soldotna AK
Avid "C" / Mk IV
582 (147 hrs and counting on the rebuild)
IVO IFA
Full Lotus 1450
#1 snake oil salesman since 1-22-2009

I would rather die trying to live, than to live trying not to die....

matronics(at)bob.brennan.
Guest

Posted: Mon Apr 13, 2009 7:29 am Post subject: Kitfox Model II flight behavior

Joe - my Model 2 also exhibits the same  characteristics, as I believe all un-modified Model 2's do.

  

 From the Kitfox website at http://www.kitfoxaircraft.com/Model%20III.htm:

  

 "The Model 3 was the first major attempt to aggressively deal  with the yaw control issue.  It should be remembered that we are not  talking about yaw instability, but a neutral yaw condition.  In other  words, it was desired to have the airplane return to straight flight after  pressing a rudder without having to move it back with your feet.  Much of  this objective was achieved by increasing the size of the vertical  fin."

  

 Bottom line is -  there's no cruise control on a Model 2, you have to fly it with your feet on the  rudders at all times. Being a Model 2 owner I'd like to cite some positive  benefit like "makes you a better pilot" but really it was just an evolving  design and as the Models evolved certain things were changed. Come to think of  it - when I flew Pipers I used to think a Cessna was a difficult plane to fly,  now after flying the Kitfox the Cessna is like driving a car! And just as  slow...

  

 As we say in the Engineering World - it's not a flaw,  it's and undiscovered feature. 

  

 Bob Brennan - N717GB

 ELSA Repairman, inspection rated

 1991 UK Model 2 ELSA Kitfox taildragger

 Rotax 582 with 3 blade prop

 Wrightsville Pa

  

 



   From: owner-kitfox-list-server(at)matronics.com  [mailto:owner-kitfox-list-server(at)matronics.com] On Behalf Of Joe &  Jan Connell

Sent: 13 April 2009 10:55 am

To:  kitfox-list(at)matronics.com

Subject: Kitfox Model II flight  behavior

 

 Gentlemen,



I've been flying my Kitfox-II for about 12 years.   An item in the May issue of "Flying" magazine is prompting this note.  One  paragraph in an article called "Aftermath" by Pete Garrison states the  following:



"I have very limited experience in LSAs, but one very popular  model that I have flown had surprising flight characteristics, including a  rudder so whimsical that it would remain at either stop, fully deflected, while  the pilot's feet were flat on the floor and the airplane flew merrily along in a  gigantic sideslip. This is the kind of behavior that one associates with the  First World War, not the 21st century."

  

 My Kitfox-II exhibits the exact characteristic!  If my feet are on the  floor, I will get a very strong adverse yaw just by moving the wings a  bit.  If I look in the rearview mirror I can see the rudder is fully  deflected.  It's as if the short fuselage and the small vertical stabilizer  are insufficient to prevent yaw in straight flight.  If I remember, the  Model-III and above have a much larger vertical stabilizer (with an  airfoil) and rudder assembly.  The Kitfox has long wings relative to  fuselage.

  

 Is anyone else experiencing this condition?  I'm thinking of adding  some sort of centering springs to keep the rudder centered in straight and level  flight.  I've even toyed with the idea of replacing the rudder with a  larger later model...

  

  

 Joe Connell

 Kitfox-II N62JK

[quote]



href="http://www.matronics.com/Navigator?Kitfox-List">http://www.matronhref="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/c

[b]

kerrjohna(at)comcast.net
Guest

Posted: Mon Apr 13, 2009 7:39 am Post subject: Kitfox Model II flight behavior

why fly with your feet on the floor?  they have built-in springs that can develop memory of what feels right.  Put them on the rudder pedals and use them.



John Kerr



---

Fox5flyer
Guest

Posted: Mon Apr 13, 2009 7:58 am Post subject: Kitfox Model II flight behavior

Since you've been flying yours for 12 years I'd be  the last one to try to tell you how to fly it because you already know that, and  very well.  What you have is typical adverse yaw which is typical of the  early Foxes.  Snakeman explained it very well.  Mine did the same  thing, but after a few flights it became second nature and wasn't a  problem.  There is something you can do about it, but is it worth  it?

 Deke Morisse

Mikado Michigan

S5/Subaru/CAP  402+ TT

"The aim of an argument or discussion should not be victory, but  progress."

- Joseph Joubert

  

 

 

 [quote]   ---

msm_9949(at)yahoo.com
Guest

Posted: Mon Apr 13, 2009 8:09 am Post subject: Kitfox Model II flight behavior

As a practical matter, it means keeping your feet on the pedals and cross-controlling a tad to keep the ball centered in a turn. It's a quirk but you quickly get used to it. Personally, I don't think it needs fixing nor would I go so far as to say this benign characteristic makes the Model II a throwback to WW1. 

  

 Marco Menezes N99KX

 Model 2 582-90 C-Box 3:1 w/clutch

 

--- On Mon, 4/13/09, akflyer <akflyer_2000(at)yahoo.com> wrote:



  	  Quote: 	
		  

From: akflyer <akflyer_2000(at)yahoo.com>

Subject: Re: Kitfox Model II flight behavior

To: kitfox-list(at)matronics.com

Date: Monday, April 13, 2009, 11:11 AM



 --> Kitfox-List message posted by: "akflyer" <akflyer_2000(at)yahoo.com (akflyer_2000(at)yahoo.com)>



The "very strong adverse yaw" comes from the flaperon mixer design.  While a larger vertical stab will help the issue, the real bottom line is the flaperons travel 2X more down than they do up.  The down flaperon creates more drag and pull you to that side ( you roll right and the nose goes to the left).  New mixers mods, will give you 2X more up than down and the majority of the adverse yaw goes away.



When setting my large models up for competition, it takes atleast 35 or 40 flights to get all the bad habits mixed out of the plane.  One of the biggest issues is getting aileron travel dialed in so you perfectly axial rolls.  This generally ends up have 2 to 2.5 times more up travel than  down.



You can get the model IV mixer system from KF and retro it to your plane, but if you have been flying it this way for 12 years I think you have a handle on it.



Personally I think it makes you a better pilot because it forces you to use your feet..... alot.



--------

DO NOT ARCHIVE

Leonard Perry aka SNAKE

Soldotna AK

Avid &quot;C&quot; / Mk IV 

582 IVO IFA

Full Lotus 1260

#1 snake oil salesman since 1-22-2009



hander outer of humorless darwin awards





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=238909#238909

http://www.matronics.com/Navigator?K              - MATRONICS WEB FORUM;             ="http://www.matronics.com/contribution" target=_blank>http://www.matro=====================





	


         [quote][b]

matronics(at)bob.brennan.
Guest

Posted: Mon Apr 13, 2009 8:23 am Post subject: Kitfox Model II flight behavior

Sounds like a lot of snake-oil to me! 



I'm reviewing the Kitfox website about this issue Leonard, and it is

addressed in 3 places:



1. From Model 2 to 3 the vertical stabiliser size is increased to go from

yaw-neutral to yaw-positive.



2. From 3 to 4 the flaperon mixer is changed to the 2x configuration so that

it would "handle like a contemporary, certified airplane", the effect being

"rudder coordination was made much easier", but "while yaw stability was no

longer neutral, it was not aggressively positive".



3. Series 5 vertical fin changes were apparently the final solution:

"Refinements to the vertical tail surfaces and a new, trimable, horizontal

stabilizer enhanced the pitch feel.  The Series 5 has a "smoother" feel than

the quick reacting Model 4, but retains the overall agility.  Yaw stability

is positive and good."



So by my reading it was changes to the vertical fin in 3 and 5 that

corrected the yaw "feature" of Models 1 and 2, not the flaperon change; or

am I interpreting it wrong?



Gotta keep an eye on these snake oil salesmen <wink>



Bob Brennan - N717GB

ELSA Repairman, inspection rated

1991 UK Model 2 ELSA Kitfox taildragger

Rotax 582 with 3 blade prop

Wrightsville Pa



--

Aerobatics(at)aol.com
Guest

Posted: Mon Apr 13, 2009 8:24 am Post subject: Kitfox Model II flight behavior

A fix that helps....   is sealing the gaps on rudder ( elevator  should be too)   and flying a forward CG

  

 I found the simple mod to make a big improvement....

  

 good luck

  

 KF 2  582 BH    450 hrs

  

  In a message dated 4/13/2009 10:59:23 A.M. Central Daylight Time,  fox5flyer(at)idealwifi.net writes:

 [quote]   Since you've been flying yours for 12 years I'd    be the last one to try to tell you how to fly it because you already know    that, and very well.  What you have is typical adverse yaw which is    typical of the early Foxes.  Snakeman explained it very well.  Mine    did the same thing, but after a few flights it became second nature and wasn't    a problem.  There is something you can do about it, but is it worth    it?

   Deke Morisse

Mikado Michigan

S5/Subaru/CAP    402+ TT

"The aim of an argument or discussion should not be victory, but    progress."

- Joseph Joubert

    

   

 

   [quote]     ---

matronics(at)bob.brennan.
Guest

Posted: Mon Apr 13, 2009 8:55 am Post subject: Kitfox Model II flight behavior

My flight instructor in the Kitfox (old-school tailwheel)  taught me to correct roll due to turbulence with the rudder, not the stick.  After experimenting I find this does indeed work better, on my Model 2 at least.  When flying a 172 I still use the yoke to correct for roll and the rudder pedals  are footrests. Maybe I'll try rudder control for roll on Pipers and Cessnas next  time I'm flying one to see if it works as well as it does in my KF2.  

  

 Anyone else have any experience with  this?

  

 Bob Brennan - N717GB

 ELSA Repairman, inspection  rated

 1991 UK Model 2 ELSA Kitfox  taildragger

 Rotax 582 with 3 blade  prop

 Wrightsville Pa

 

 

   From: owner-kitfox-list-server(at)matronics.com  [mailto:owner-kitfox-list-server(at)matronics.com] On Behalf Of Marco  Menezes

Sent: 13 April 2009 11:54 am

To:  kitfox-list(at)matronics.com

Subject: Re: Re: Kitfox Model  II flight behavior

 

                   As a practical matter, it means keeping your feet on the pedals        and cross-controlling a tad to keep the ball centered in a        turn. It's a quirk but you quickly get used to it. Personally, I don't        think it needs fixing nor would I go so far as to say this benign        characteristic makes the Model II a throwback to WW1. 

        

       Marco Menezes N99KX

       Model 2 582-90 C-Box 3:1 w/clutch

       

--- On Mon, 4/13/09, akflyer        <akflyer_2000(at)yahoo.com> wrote:



        	  Quote: 	
		  

From:          akflyer <akflyer_2000(at)yahoo.com>

Subject: Re:          Kitfox Model II flight behavior

To:          kitfox-list(at)matronics.com

Date: Monday, April 13, 2009, 11:11          AM



         --> Kitfox-List message posted by: "akflyer"          <akflyer_2000(at)yahoo.com (akflyer_2000(at)yahoo.com)>



The          "very strong adverse yaw" comes from the flaperon mixer design.           While a larger vertical stab will help the issue, the real bottom line          is the flaperons travel 2X more down than they do up.  The down          flaperon creates more drag and pull you to that side ( you roll right          and the nose goes to the left).  New mixers mods, will give you 2X          more up than down and the majority of the adverse yaw goes          away.



When setting my large models up for competition, it takes          atleast 35 or 40 flights to get all the bad habits mixed out of the          plane.  One of the biggest issues is getting aileron travel dialed          in so you perfectly axial rolls.  This generally ends up have 2 to          2.5 times more up travel than down.



You can get the model IV          mixer system from KF and retro it to your plane, but if you have been          flying it this way for 12 years I think you have a handle on          it.



Personally I think it makes you a better pilot because it          forces you to use your feet..... alot.



--------

DO NOT          ARCHIVE

Leonard Perry aka SNAKE

Soldotna AK

Avid          &quot;C&quot; / Mk IV 

582 IVO IFA

Full Lotus 1260

#1          snake oil salesman since 1-22-2009



hander outer of humorless          darwin awards





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=238909#238909

http://www.matronics.com/Navigator?K                       - MATRONICS WEB FORUM;                               ="http://www.matronics.com/contribution"          target=_blank>http://www.matro=====================





	


[quote]



href="http://www.matronics.com/Navigator?Kitfox-List">http://www.matronhref="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/c

[b]

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Mon Apr 13, 2009 9:38 am Post subject: Re: Kitfox Model II flight behavior

 	  matronics(at)bob.brennan. wrote: 	
		  Sounds like a lot of snake-oil to me! 



I'm reviewing the Kitfox website about this issue Leonard, and it is

addressed in 3 places:



1. From Model 2 to 3 the vertical stabiliser size is increased to go from

yaw-neutral to yaw-positive.



2. From 3 to 4 the flaperon mixer is changed to the 2x configuration so that

it would "handle like a contemporary, certified airplane", the effect being

"rudder coordination was made much easier", but "while yaw stability was no

longer neutral, it was not aggressively positive".



3. Series 5 vertical fin changes were apparently the final solution:

"Refinements to the vertical tail surfaces and a new, trimable, horizontal

stabilizer enhanced the pitch feel.  The Series 5 has a "smoother" feel than

the quick reacting Model 4, but retains the overall agility.  Yaw stability

is positive and good."



So by my reading it was changes to the vertical fin in 3 and 5 that

corrected the yaw "feature" of Models 1 and 2, not the flaperon change; or

am I interpreting it wrong?



Gotta keep an eye on these snake oil salesmen <wink>



Bob Brennan - N717GB

ELSA Repairman, inspection rated

1991 UK Model 2 ELSA Kitfox taildragger

Rotax 582 with 3 blade prop

Wrightsville Pa



-- 	




Take a look at the 3-4.



It is basic lift versus drag.  If at first they could not figure out how to update the mixer, the only solution was to increase rudder / fin size.  John Stoner did the math, figured out the issue and made a new mixer that worked right.  That was on a model III.



No snake oil here, heck even Deke said I explained it well.. and if Deke agrees with me then by golly you better get your affairs in order cause the end is coming soon LOL.

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Mon Apr 13, 2009 9:53 am Post subject: Re: Kitfox Model II flight behavior

Think Mc Bean has a mixer retrofit kit but best to ask him if it will fit.

The Iv model has different flapperons as well ( symmetrical ) and I am no sure if that changes it at all. 



I was out with a guy in a KF 2 today for  1.5 hours  doing X wind circuits.  wind was 11 G 15 knots and had no problems doing 45 degree landings on grass. We went to another strip that was   80 degrees cross and still no problem .  He is a newer pilot and just transitioning to tailwheel after one season on tri gear then about 10 hours  skis in tail dragger config. 



Best to just learn to fly more with Rudder as you should be .  Really not a big deal.

_________________
Realtime Kitfox movies to separate the internet chatter from the truth
http://www.youtube.com/user/kitfoxflyer
Hundreds of Kitfox Movies
Most viewed Kitfox on youtube
Most popular on youtube
Highest rated on youtube

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Mon Apr 13, 2009 10:06 am Post subject: Kitfox Model II flight behavior

Ouch! I felt that zinger clear down South here, Snake..... : )



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 628.1 hrs

Sensenich 62x46

Electroair direct-fire ignition system

Status: flying

do not archive



On Apr 13, 2009, at 1:38 PM, akflyer wrote:

 	  Quote: 	
		  

 No snake oil here, heck even Deke said I explained it well.. and if  

 Deke agrees with me then by golly you better get your affairs in  

 order cause the end is coming soon LOL.



 --------

 DO NOT ARCHIVE

 Leonard Perry aka SNAKE

 Soldotna AK

 Avid &quot;C&quot; / Mk IV

 582 IVO IFA

 Full Lotus 1260

 #1 snake oil salesman since 1-22-2009



 hander outer of humorless darwin awards





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 38959#238959

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Mon Apr 13, 2009 10:18 am Post subject: Kitfox Model II flight behavior

At 07:55 AM 4/13/2009, you wrote:

 	  Quote: 	
		  My Kitfox-II exhibits the exact characteristic!  If my feet are on 

the floor, I will get a very strong adverse yaw just by moving the 

wings a bit.  If I look in the rearview mirror I can see the rudder 

is fully deflected.  It's as if the short fuselage and the small 

vertical stabilizer are insufficient to prevent yaw in straight flight.


	


First of all, your case and the example are two completely different 

things. The example is of neutral static stability. When deflected 

the aircraft remains in its deflected state, neither returning nor 

diverging from the deflected condition. It is possibly quite 

dangerous because generally perfect neutral stability in aerodynamics 

is hard to achieve. With a slight configuration change, the example 

aircraft might just shift to negative stability, increasing in yaw 

from a deflected condition. Thus were the rudder controls to fail the 

aircraft would depart from controlled flight, not a good idea.



In your case you are simply seeing the rudder wag back and forth as 

you work the ailerons. This does not mean you have negative or even 

neutral static stability. And yes it caused by adverse yaw. All 

aircraft will exhibit this behavior. And all aircraft have 

substantially less static yaw stability without the rudder than with. 

The Bonanza I flew would waddle all over without the feet on the pedals.

Guy Buchanan

San Diego, CA

K-IV 1200 / 582-C / Warp / 300 hrs. and counting

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Mon Apr 13, 2009 10:19 am Post subject: Re: Kitfox Model II flight behavior

 	  Lynn Matteson wrote: 	
		  Ouch! I felt that zinger clear down South here, Snake..... : )



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 628.1 hrs

Sensenich 62x46

Electroair direct-fire ignition system

Status: flying

do not archive

	




Was not ment to be anything other than a funny...  I cracked myself up with it LOL.



Thinking just a touch more on the subject, the flaperon issue is dealing with nothing more than adverse yaw.  The larger fin adds to yaw stability, but does not alleviate the flaperons from being the culprit.  It is an inherent design..uhhh... not really a flaw, but a "characteristic".

matronics(at)bob.brennan.
Guest

Posted: Mon Apr 13, 2009 10:34 am Post subject: Kitfox Model II flight behavior

So you're saying that if Deke agrees with you then hell must've frozen over?

Heck I'd better review those ski postings 'cause it sounds like I'm going to

need me a set! 



Sounds like the Kitfox History pages are a little inaccurate then? You say

below "new mixer on Model 3", the website says 4. I'm assuming you meant

that John Stoner tried the new mixer on a 3 and Skystar incorporated it into

the 4? But the website still says they didn't achieve "Yaw stability

[that] is positive and good" until the Model 5 with a completely different

empennage but the same mixer as a 4.



And the lift vs drag part - so if I am turning to the right using the new

mixer the left flaperon travels further down than my Model 2, thus producing

more lift and more drag in the left wing, thus promoting yaw towards the

left... Ummmm, sounds like adverse yaw to me - BUT will require more right

rudder, which is correct. Versus my KF2 which needs right rudder in a right

turn followed by left rudder to keep the ball centered... Is that correct? I

mean the "basic lift vs drag" part of it, is that what you meant?



So I'm still a bit anally confused here. Can I order me a bottle of that

Snake Oil please, I think I need one. What proof is it BTW? 90?

<wink><nudge>



Bob Brennan - N717GB

ELSA Repairman, inspection rated

1991 UK Model 2 ELSA Kitfox taildragger

Rotax 582 with 3 blade prop

Wrightsville Pa



--

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Mon Apr 13, 2009 10:34 am Post subject: Kitfox Model II flight behavior

And I took it as funny, as I'm sure Deke did....well, maybe his sense  

of humor is waning a bit what with a soggy runway(s) and all.... : )



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 628.1 hrs

Sensenich 62x46

Electroair direct-fire ignition system

Status: flying

do not archive



On Apr 13, 2009, at 2:19 PM, akflyer wrote:



 	  Quote: 	
		   

 Lynn Matteson wrote:

> Ouch! I felt that zinger clear down South here, Snake..... : )

>

> Lynn Matteson

> Kitfox IV Speedster, taildragger

> Jabiru 2200, #2062, 628.1 hrs

> Sensenich 62x46

> Electroair direct-fire ignition system

> Status: flying

> do not archive

>

 Was not ment to be anything other than a funny...  I cracked myself  

 up with it LOL.



 Thinking just a touch more on the subject, the flaperon issue is  

 dealing with nothing more than adverse yaw.  The larger fin adds to  

 yaw stability, but does not alleviate the flaperons from being the  

 culprit.  It is an inherent design..uhhh... not really a flaw, but  

 a "characteristic".



 --------

 DO NOT ARCHIVE

 Leonard Perry aka SNAKE

 Soldotna AK

 Avid &quot;C&quot; / Mk IV

 582 IVO IFA

 Full Lotus 1260

 #1 snake oil salesman since 1-22-2009



 hander outer of humorless darwin awards





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 38974#238974

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Paul A. Franz, P.E.

Joined: 02 Dec 2008
Posts: 280
Location: Bellevue WA

Posted: Mon Apr 13, 2009 10:54 am Post subject: Kitfox Model II flight behavior

On Mon, April 13, 2009 8:56 am, fox5flyer wrote:

 	  Quote: 	
		   What you have is typical adverse yaw which is typical of the early Foxes.


	


Deke - maybe this is a matter of semantics but adverse yaw is not this. Adverse yaw is

the amount of rudder input you have to supply to compensate for increased drag on the

outboard wing in a turn. If it were frictionless, then a coordinated turn with

ailerons would need no rudder input.



If I'm understanding correctly, what is happening is that there is no apparent

restoring force to return the rudder to a neutral position and the plan will happily

fly along in a skid without any applied force to the rudder.



-- 

Paul A. Franz

Registration/Aircraft - N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue WA

425.241.1618 Cell



We the unwilling, led by the ungrateful, are doing the impossible.

We've done so much, for so long, with so little,

that we are now qualified to do something with nothing.

-- anonymous



Under every stone lurks a politician.

                -- Aristophanes



Giving money and power to governments is like giving whiskey and

car keys to teenage boys.

        -- P.J. O'Rourke

_________________
Paul A. Franz, P.E.
Registration/Aircraft - N14UW/Merlin GT
Engine/Prop - Rotax 914/NSI CAP
Bellevue WA
425.241.1618 Cell
425.440.9505 Office

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Mon Apr 13, 2009 11:14 am Post subject: Re: Kitfox Model II flight behavior

 	  matronics(at)bob.brennan. wrote: 	
		  So you're saying that if Deke agrees with you then hell must've frozen over?

Heck I'd better review those ski postings 'cause it sounds like I'm going to

need me a set! 



Sounds like the Kitfox History pages are a little inaccurate then? You say

below "new mixer on Model 3", the website says 4. I'm assuming you meant

that John Stoner tried the new mixer on a 3 and Skystar incorporated it into

the 4? But the website still says they didn't achieve "Yaw stability

[that] is positive and good" until the Model 5 with a completely different

empennage but the same mixer as a 4.



And the lift vs drag part - so if I am turning to the right using the new

mixer the left flaperon travels further down than my Model 2, thus producing

more lift and more drag in the left wing, thus promoting yaw towards the

left... Ummmm, sounds like adverse yaw to me - BUT will require more right

rudder, which is correct. Versus my KF2 which needs right rudder in a right

turn followed by left rudder to keep the ball centered... Is that correct? I

mean the "basic lift vs drag" part of it, is that what you meant?



So I'm still a bit anally confused here. Can I order me a bottle of that

Snake Oil please, I think I need one. What proof is it BTW? 90?

<wink><nudge>



Bob Brennan - N717GB

ELSA Repairman, inspection rated

1991 UK Model 2 ELSA Kitfox taildragger

Rotax 582 with 3 blade prop

Wrightsville Pa



-- 	


well... in a short word... NO



John recognized the problem and made his own mixer for his model 3.  He had conversations with the factory that led to the model 4 having a different mixer.



The old mixer works like this.  You give right roll input and the right flaperon goes up only half the distance the left flaperon goes down.  This makes the left flaperon produce a butt load of drag and pulls the nose to he left, making you use LOTS of right rudder to counteract this force.



The new mixer if you give it right roll input the right flaperon goes up twice as much as the left one goes down, making less drag on the left side, therefore, you need less right rudder input.



If I lost you on that one, you will need more than one bottle of snakeoil.  I am having a batch brewed up in high hills of kentucky that will be 190 to 200 proof, so please, dont do shots of it, it is for "sipping" only!

matronics(at)bob.brennan.
Guest

Posted: Mon Apr 13, 2009 11:53 am Post subject: Kitfox Model II flight behavior

Sorry to drag this on, pour us both a shot of that Snake Oil would ya...



So you're saying that this John Stoner, sorry I don't know who he is,

corrected *his* yaw problem on *his* Model 3; but it has nothing to do with

production kits, where a new mixer was introduced on the Model 4 but they

got it all wrong... I'm getting dizzy, and what does that have to do with

the price of Snake Oil? 



Am I right in saying Models 1 and 2 have the same neutral-yaw problems, 3

and 4 have the same positive yaw but weak, and Model 5 finally has the same

positive yaw characteristics as spam cans? And that 1 and 2 have the same

small vertical stabilizers, 3 and 4 the same larger stabilizers, and 5 is a

completely re-designed empennage? And 1, 2 and 3 have 1:1 mixers and 4 and

up have the 2:1 mixers. Sure sounds to me like it was the bigger better butt

that made the difference to the yaw(ning) problem, not the mixer.



BTW I bought some 60 proof "cask strength" Macallan single malt once - they

recommend you mix it with spring water "to taste". I found it was best

straight, over a few ice cubes. [hic] Ever thought of selling that Snake Oil

as a BBQ lighter?



Bob Brennan - N717GB

ELSA Repairman, inspection rated

1991 UK Model 2 ELSA Kitfox taildragger

Rotax 582 with 3 blade prop

Wrightsville Pa



--

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Mon Apr 13, 2009 1:41 pm Post subject: Re: Kitfox Model II flight behavior

uhhhh... no again.. swing batter swing... strike!



 And 1, 2 and 3 have 1:1 mixers 



NO.  I, II and III have 2:1 going the wrong way from the factory.



You be getting yaw, adverse yaw, and yaw stability scrambled more than a breakfast skillet at Denny's.



someone else want to take a shot at this one LOL.

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