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Aileron Forces

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ssumm

Joined: 22 Mar 2007
Posts: 3
Location: Sacramento

Posted: Wed Jun 27, 2007 11:06 am Post subject: Aileron Forces

I have a Firestar II and note that the roll rate is very low and the stick forces in a roll relatively high.  The archives indicate that spades are not appropriate for this aircraft.  Some people have reduced the chord length (front to rear) from some 15 to 9 inches to lighten the stick forces.  I would like some more information from people who have done this to Kolb aircraft and, in particular, how a new chord length determined (e.g., would 12 or 16 inches work better/ worse).  Thanks.  

     

  6/26/2007 11:54 PM

     [quote][b]

jb92563

Joined: 23 Mar 2007
Posts: 314
Location: Southern California

Posted: Wed Jun 27, 2007 12:00 pm Post subject: Re: Aileron Forces

Narrowing the aileron chord length seems like it would not help.



A narrower chord would require less control force...true enough, but the aileron would have less effectiveness for a given deflection, requiring an increase of deflection angle which would require more force, but now the deflection angle of the aileron is greater causing more adverse yaw and more rudder to correct for that.



Seems like you would end up back where you started only worse.



Alternatively I might suggest that the force may be greater on the down going aileron than the upwards deflection so perhaps adjusting the differential aileron throw is a better place to start working on this problem.



Also perhaps you need more leverage to lighten the stick force, so you either could make the stick longer or move the contol attach point closer to the pivot.



I think the aileron size has been optimized by the designer, I would play with the mechanical parts and try carefully adjusting those a bit at a time until you are happier with the forces.



Just 2 cents from a test pilot.

_________________
Ray

Kolb UltraStar (Cuyuna UL-202)
Moni MotorGlider
Schreder HP-11 Glider
Grob 109 Motorglider

Do Not Archive

planecrazzzy
Guest

Posted: Wed Jun 27, 2007 12:27 pm Post subject: Re: Aileron Forces

In the picture below  ( attached )



 You can see where I first put my aileron control rods....



 it was suggested by "list members" to light the stick pressure.....



 As you can see , I put it back in the "stock position"



  The stick pressure isn't that bad , and I wanted more control for 



those BIG gusts of wind....

Gotta Fly...

Mike & "Jaz" in MN /  FSII - N381PM

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NeilsenRM(at)comcast.net
Guest

Posted: Wed Jun 27, 2007 12:53 pm Post subject: Aileron Forces

I'm going to stick my neck out here and tell you  what I think. I wouldn't for a second consider reducing the cord of the ailerons  or as a few have done move the pivot point of the aileron bell  crank in to reduce the deflection of the ailerons. My MKIIIC  ailerons require a fairly high force to deflect them at high speeds  but when I really need them, low speed and near the ground, they are much  lighter. Our Kolbs aren't aerobatic airplanes and as such don't need roll rates  of 90 degrees per second. These planes do need powerful ailerons at slow  speeds when we are doing takeoffs and landings. I can't always fly in  perfect weather so if I get caught in turbulence near the ground I want as  much control as I can get. If the control forces are high enough that  I have to muscle them a bit that is much better than hitting the control  stop wishing I had more. 

  

 As for spades I don't think anyone that knows how  they work would say they are not appropriate. The problem has been building them  so that they work well and maybe not too well. I noticed Craig Nelson has a  small set attached to the balance weights on his MKIIIX and stated that they  were too small. There has been some discussion that there are complex  wind patterns at the wing tips that complicates or maybe eliminates the  effectiveness of these spades.    

  

 I know of a Firestar II that had spades on  them (mid span below the wing) at one time and the reports were that they worked  very very well. There were concerns of stressing the aileron hinges so they  were removed. Another concern would be that the ailerons could be deflected  further at high speeds than the wing or ailerons were designed to handle.  If you think about it Homer designed them to be effective at low speeds yet  keeping the pilot from damaging the airframe at high speeds. 

  

 My $.02 worth

  

 Rick Neilsen

 Redrive VW powered MKIIIC

 [quote]   ---

Richard Pike

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

Posted: Wed Jun 27, 2007 1:31 pm Post subject: Aileron Forces

Go look at this page for the Firestar  II:

 http://www.bcchapel.org/pages/0003/FSII%20ailerons.html

  

 and this one for the MKIII:

 http://www.bcchapel.org/pages/0003/pg7.htm

  

 It's simple, it works, if you don't like it,  put it back like it was.

  

 Richard Pike

 MKIII N420P (420ldPoops)

 [quote]   ---

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

John Hauck

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

Posted: Wed Jun 27, 2007 1:51 pm Post subject: Aileron Forces

I'm going to stick my neck out here and tell you what I think.



Rick Neilsen



Hi Rick:



Excellent post.



Glad you stuck your neck out.



Reference "aileron spades", I, personally, would not put them on my 

mkIII, or any other model Kolb.  I have not found a requirement to 

crank the ailerons, lock to lock, at higher speeds.  Just the 

opposite.  Homer Kolb told me many years ago to fly it gently, input a 

little roll and she would roll right up.  Just be patient.



Had a very experienced friend die in a Firestar wing failure.  I 

believe part of that failure was caused by aileron spades creating 

more stress than the 5 rib wing panel could handle.  Some of us have 

been able to cause wing failures without spades on the old 5 rib 

wings.



Take care,



john h

mkIII

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

jbhart(at)onlyinternet.ne
Guest

Posted: Wed Jun 27, 2007 6:25 pm Post subject: Aileron Forces

 	  Quote: 	
		  I have a Firestar II and note that the roll rate is very low and the stick 

forces in a roll relatively high.  The archives indicate that spades are not 
	


appropriate for this aircraft.  Some people have reduced the chord length 

(front to rear) from some 15 to 9 inches to lighten the stick forces.  I 

would like some more information from people who have done this to Kolb 

aircraft and, in particular, how a new chord length determined (e.g., would 

 	  Quote: 	
		  12 or 16 inches work better worse).  Thanks.


	


Hi,



I have an early FireFly on which I replaced the fifteen inch chord ailerons 

with nine inch chord ailerons after flying it just four hours. Later I 

modified the control linkages.  This greatly improved roll rate and reduced 

stick pressures.  It turned an around the patch quiet air machine into an 

any time of the day machine.  It is a pure delight to fly in rough air.  It 

effortlessly forward or side slips.  The only thing, that I gave up was a 

little wing area, and I had to accept a small increase in stall speed.  I 

got the stall speed back with vortex generators.



There is a misconception that large ailerons are better.  But roll rate is 

influenced by the change in the angle of the wing chord as the aileron is 

deflected.  If you have a long chord aileron, the dynamic loading will be 

high and stick pressure will higher than it needs to be at any speed.  By 

reducing the aileron chord, the dynamic loading goes down for the same 

aileron deflection and stick pressure goes down too.



I don't know if this will help you with your Firestar, but you can see some 

more at:



http://www.thirdshift.com/jack/firefly/firefly26.html



If you make new ailerons save your old ones in case you need to put them 

back one.  I still have mine in the barn.  They have about seven years of 

dust on them.



The nine inch chord came about in the following way.  I hangared in a 

communal hangar and they were cementing the floor.  I helped to move and 

pack planes so two bays would be open for the concreters.  I got out my 

measuring tape and measured wing and aileron chords.  And using an incline 

meter, I measured aileron up and down deflections.  All of these aircraft 

flew very well with much less aileron length and total aileron deflection.



Be careful, and fly safe.



Jack B. Hart FF004

Winchester, IN

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Wed Jun 27, 2007 8:20 pm Post subject: Re: Aileron Forces

The aileron forces on the Kolb MK III are unreasonably high, and I have also been working to reduce my Aileron Forces...   The Kolb is not an aerobatic airplane and does not need to roll fast, but there is no reason in the world that the roll should be hard and require a lot of effort.  



First problem is in the linkage design, Kolbs have WAY TO MUCH travel built into the ailerons.  My Kolb MK III Xtra had 40 degrees of up aileron which is as much or more than a highly aerobatic Extra 300.  This is a design error by Kolb and needs to be fixed...  I found even than in crosswinds etc, I never used anywhere near full stick.  Secondly, anything past 25 or 30 degrees travel turns into drag, and does not give you more control.   The easy way to fix this on a MK III is to shorten where the aileron rods attach at the rear of the fuselage as seen in the attached picture, but this brings other problems.   First, it increases the angle of the aileron control rods to the point where they are pushing out as much as they are pushing the aileron up and down, so some of what you gained is also wasted.  Secondly, it increases the aileron differential to an unreasonable amount.  In other words, you get a lot of up, but very little down aileron the more you move these rods in..  Not good and I did not use this method to lighten my control forces.    My solution was to drill a hole in the bottom of the stick, and shorten the aileron attach point to the stick, resulting in less throw and less force without all the disadvantages of the other methods.  In the picture, I just drilled another hole above hole where the bolt that attaches to the stick, moving the attachment point up.  This picture was before the modification, you can clearly see how much extra room there is to drill a higher hole.



Spades would be great,  I plan on doing this when I have time.  As far as stress, that is a matter of having the skill and judgement not to yank hard and overstress the ailerons at high speed, but that is the case with almost any airplane you fly.   Big control inputs at high speeds are bad, from ultraights to airliners... Thats called pilot technique.  I dont need rock hard control forces to keep me from doing something stupid.  I would rather have an easy to fly airplane that does not tire me out quickly.



I would NOT shorten the ailerons, that reduces wing area and aileron area.   There is no need to do this with other better, and easier options avialable.

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

Kolb MK-III Xtra, 912-S

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Wed Jun 27, 2007 8:40 pm Post subject: Re: Aileron Forces

I havn't flown a MKIII yet, but my FS II's aileron forces are very light. In fact, it has the lightest control forces that I've flown to my recollection, especially in roll. My titan for example has spades on it, but still requires significantly more muscle in roll than my firestar II.



It's very easy for me to get the stick over to the stop at any speed. The torque rod from the stick going back to the bellcrank for the aileron pushrods seems to flex twist-wise, limiting the aileron movement at cruise speeds even with the stick pegged all the way to the stop.

With gap seals on the ailerons, there's still a fair bit of roll authority. It doesn't roll like a pitts to be sure, but it's still pretty good.



But I used to think this was goofy with the stick over at the stop but the aileron barely deflecting. But having researched it more, I'd bet if more force were able to be applied to the ailerons, it would probably exceed design limits probably in the hinges and perhaps in the wing panels.

And they do move more at lower speeds, where more movement is needed, due to the lower airspeeds....



So... JMO...I'd say no mods to the ailerons or the linkage are really needed or should be attempted, I think it's operating as designed and works best as is. 



Gaps seal are specified for the ailerons, which I make out of shipping tape and replace about once a year. This greatly improves the aileron response over a non-sealed gap...



I can't explain it, I just love this airplane. My titan will fly circles around it literally but in calm weather my Kolb with it's little 503 screamer is what I prefer to fly by far.....



LS

_________________
LS
Titan II SS

slyck(at)frontiernet.net
Guest

Posted: Thu Jun 28, 2007 4:52 am Post subject: Aileron Forces

I moved mine in about half of Richard P's distance and was happy with  

the result.  Plenty

of control and just the right stick resistance.  Like he says, if not  

what you want, just move

them back.

BB  MkIIIc, suzuki 3 cyl,  65" powerfin

Steve Boetto

Joined: 11 Jan 2006
Posts: 364

Posted: Thu Jun 28, 2007 7:24 am Post subject: Aileron Forces

In a message dated 6/27/2007 10:25:36 P.M. Eastern Standard Time,  jbhart(at)onlyinternet.net writes:

  	  Quote: 	
		  

I    have an early FireFly on which I replaced the fifteen inch chord ailerons    

with nine inch chord ailerons after flying it just four hours. Later I    

modified the control linkages.  This greatly improved roll rate and    reduced 

stick pressures.  It turned an around the patch quiet air    machine into an 

any time of the day machine.  It is a pure delight to    fly in rough air.  It 

effortlessly forward or side slips.  The    only thing, that I gave up was a 

little wing area, and I had to accept a    small increase in stall speed.  I 

got the stall speed back with    vortex generators.

	


 

 Hi Jack,

  

 A few years ago when we were re covering my Firefly I asked Homer about the  big Ailerons. He recommended  that I reduce them to 9". It made a big  difference in FF 007 and very little change in other areas due to reduced wing  area.

  

 Steve

 FF 007



See what's free at AOL.com. 

  [quote][b]

jbhart(at)onlyinternet.ne
Guest

Posted: Thu Jun 28, 2007 1:17 pm Post subject: Aileron Forces

From: N27SB(at)aol.com

  

A few years ago when we were re covering my Firefly I asked Homer about the big Ailerons. He recommended  that I reduce them to 9". It made a big difference in FF 007 and very little change in other areas due to reduced wing area.

  

Steve,



Did Homer tell you why nine inch chord was a good number?



Jack B. Hart FF004

Winchester, IN

Steve Boetto

Joined: 11 Jan 2006
Posts: 364

Posted: Thu Jun 28, 2007 6:19 pm Post subject: Aileron Forces

In a message dated 6/28/2007 5:17:54 P.M. Eastern Daylight Time,  jbhart(at)onlyinternet.net writes:

  	  Quote: 	
		  Steve,



Did Homer tell you why nine inch chord was a good    number?



Jack B. Hart FF004

Winchester,  IN

	


 

 No he did not. 9" was the current standard. Remember, Homer did not design  the Firefly.

  

  

  

 steve



See what's free at AOL.com. 

  [quote][b]

jim

Joined: 03 Nov 2006
Posts: 107
Location: N. Idaho

Posted: Thu Jun 28, 2007 10:36 pm Post subject: Aileron Forces

I moved the flaperon linkages inboard 3/4" on my Firefly tonight (original

15" flaperon chord).  If you do yours, make sure you measure the new hole

positions from the centerline, not the outboard edge of the arm.  Turns

out the arm was not welded on centerline and one arm is longer than the

other.  Difference is about 1/8".  Still better than it was.  Air was

smooth as silk after sunset.



Thanks to this list for the suggestion.



Jim

N. Idaho

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Jim
N. Idaho

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