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Sensitive Elevator
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jonathan(at)entry.co.za
Guest

Posted: Tue Nov 21, 2006 10:09 pm Post subject: Sensitive Elevator

Hi All wise ones.....



I now have over 50hrs on my 601XL, and am loving every minute., but have been

woundering if I could make it better?



The Elevator is very sensitive, in comparison to the Ailerons, I am sure

everyone will agree with me, now this in itself is not an issue, as I have

become used to the elevator, and in normal smooth flight it is not an issue at

all. 



This last weekend I flew in quite severe turbulence, you know the head hitting

the canopy type of turbulence. This in itself is not an issue for the XL, as it

is very controllable in turbulence, except I feel that due to the overly

sensitive elevator, me as pilot in command tended to induce pitch oscillations.



The amount of movement on the stick (I have the dual stick option), for flare

and normal flight, is very little, thus would it not be a good idea to reduce

the snsitivity around neutral, by reducing the size of the front bellcrank. The

belcrank that the two cables attach to, in the centre console, the one the

centre single stick is attached to. This would result in the stick having to be

moved a greater distance, for the same elevator deflection. Hence reducing the

sesitivity around neutral.



The same could be achieved by increasing the horn length on the elevator itself,

but this seems like a lot more work. I think cutting down the horn size, or

making another, and fitting it for testing could be an easily achieved option.



Has anyone done this, and what do you guys think of the idea?



Thnx

Jonathan Starke

601XL Rotax 912S 50+ Hrs

Cape Town

South Africa.

daveaustin2(at)can.rogers
Guest

Posted: Wed Nov 22, 2006 6:03 am Post subject: Sensitive Elevator

Negative, John, negative.

Either of those changes would reduce the full travel of the elevators, which

you may well need in the future to save your life!

Dave Austin  601HDS - 912, Spitfire Mk VIII

carlossa52(at)gmail.com
Guest

Posted: Wed Nov 22, 2006 6:08 am Post subject: Sensitive Elevator

Jonathan, would it be possible to use the same bellcrank for that purpose?

Just add holes closer to the pivot point...



Just a thought



Carlos

CH601-HD, plans

Montreal, Canada

do not archive



 On 22/11/06, Jonathan Starke <jonathan(at)entry.co.za (jonathan(at)entry.co.za)> wrote:[quote] --> Zenith-List message posted by: "Jonathan Starke" <jonathan(at)entry.co.za (jonathan(at)entry.co.za)>



Hi All wise ones.....



I now have over 50hrs on my 601XL, and am loving every minute., but have been 

woundering if I could make it better?



The Elevator is very sensitive, in comparison to the Ailerons, I am sure

everyone will agree with me, now this in itself is not an issue, as I have

become used to the elevator, and in normal smooth flight it is not an issue at 

all.



This last weekend I flew in quite severe turbulence, you know the head hitting

the canopy type of turbulence. This in itself is not an issue for the XL, as it

is very controllable in turbulence, except I feel that due to the overly 

sensitive elevator, me as pilot in command tended to induce pitch oscillations.



The amount of movement on the stick (I have the dual stick option), for flare

and normal flight, is very little, thus would it not be a good idea to reduce 

the snsitivity around neutral, by reducing the size of the front bellcrank. The

belcrank that the two cables attach to, in the centre console, the one the

centre single stick is attached to. This would result in the stick having to be 

moved a greater distance, for the same elevator deflection. Hence reducing the

sesitivity around neutral.[b]

leinad

Joined: 19 Sep 2006
Posts: 283
Location: Central Virginia

Posted: Thu Nov 23, 2006 7:35 am Post subject: Re: Sensitive Elevator

Jonathan,

Occilations are an indication of the CG getting too far aft causing instability in the pitch axis?  Had you checked the weight and ballance?

Dan

_________________
Scratch building XL with Corvair Engine

David X

Joined: 10 Jan 2006
Posts: 154
Location: Princeton, NJ, USA

Posted: Thu Nov 23, 2006 8:48 am Post subject: Re: Sensitive Elevator

Iâ€™ve flown about 250 hours in my 601XL. In August, I flew the little bird from Albany, NY to Roseburg, OR and back to Princeton, NJ (many stops along the way, obviously). The flight across the divide and into Missoula was a thrill of a lifetime. Anyway, the point is that I hit some rough stuff on more than a few occasions and I know exactly what you mean.



The tendency is to grab the stick tighter during turbulence; which frankly makes things worse. If the plane is trimmed, there is no need for more than a light touch ... even during turbulence. Relaxation is the key. You have to get into the habit of using only the thumb and forefinger on the stick. You know the plane isn't going to do anything unusual ... so just keep a loose grip and go with it.



Watch your inclinometer during those rough patches. You'll find that the use of rudder is often much more appropriate than the use of ailerons. 3 hours across Kansas in 106 degree weather was the best rudder lesson I ever had. I thought I knew how to fly the Zodiac before, but was sure I knew after. :)



Leave the elevator geometry alone. The designer made it that way for a very good reason. In slow flight and unusual attitude situations, you will need that extra travel and command.



Safe flying.

_________________
Zodiac 601 XL - CZAW Built - Rotax 912S
DO NOT ARCHIVE

Last edited by David X on Fri Nov 24, 2006 12:19 am; edited 1 time in total

amyvega2005(at)earthlink.
Guest

Posted: Thu Nov 23, 2006 1:14 pm Post subject: Sensitive Elevator

Davud,

do you have any good pics of the trip.   Sounds like a fun one.



Juan



--

David X

Joined: 10 Jan 2006
Posts: 154
Location: Princeton, NJ, USA

Posted: Thu Nov 23, 2006 8:34 pm Post subject: Re: Sensitive Elevator

I have a few. Look for my blog and pics here: http://www.myspace.com/601nj



 	  amyvega2005(at)earthlink. wrote: 	
		  David,

do you have any good pics of the trip.   Sounds like a fun one.

_________________
Zodiac 601 XL - CZAW Built - Rotax 912S
DO NOT ARCHIVE

David X

Joined: 10 Jan 2006
Posts: 154
Location: Princeton, NJ, USA

Posted: Fri Nov 24, 2006 12:22 am Post subject: Re: Sensitive Elevator

 	  amyvega2005(at)earthlink. wrote: 	
		  David, do you have any good pics of the trip.   Sounds like a fun one. 	




Thanks for asking. I posted the story and pictures on this forum. Hopefully it will get everyone off of this gloomy speculation over crashes and thinking about the freedom and joy of flying.

_________________
Zodiac 601 XL - CZAW Built - Rotax 912S
DO NOT ARCHIVE

amyvega2005(at)earthlink.
Guest

Posted: Fri Nov 24, 2006 6:15 am Post subject: Sensitive Elevator

I looked for it in archives, can you send me the link.?

JUan



--

David X

Joined: 10 Jan 2006
Posts: 154
Location: Princeton, NJ, USA

Posted: Fri Nov 24, 2006 9:50 am Post subject: Re: Sensitive Elevator

http://forums.matronics.com/viewtopic.php?t=18892

_________________
Zodiac 601 XL - CZAW Built - Rotax 912S
DO NOT ARCHIVE

jonathan(at)entry.co.za
Guest

Posted: Mon Nov 27, 2006 12:25 am Post subject: Sensitive Elevator

Hi Dan,

The oscilations I am talking about are induced by me, when correcting in heavy

turbulence, as the slightest movement on the stick forwards or backwards causes

a pitch change. I.e. deflecting the ailerons to lidt a dropped wing in

turbulance is very dificult to not move the stick in the pitch direction as

well.



Then Weight and Balance is bang on the manual, a I would not fly it otherwise.

(Done with three digital scales, by my AMO)

Jonathan



 	  Quote: 	
		  



Jonathan,

Occilations are an indication of the CG getting too far aft 

causing instability in the pitch axis?  Had you checked the 

weight and ballance?

Dan

andrewtub

Joined: 01 Nov 2011
Posts: 18

Posted: Thu Feb 23, 2012 10:32 am Post subject: Re: Sensitive Elevator

I know this is an old subject to most, but new to me.  Here in my input on the issue that I have sent to Zenith for approval....



This improvement is a in order to help de-sensitize the elevator and better balance the controls.  Bare with me as I explain and forgive me if the is something that has been reviewed in the past.  Also this is with the dual stick option.



According to the geometry of all the cable and rod attachment points at the elevator and the control stick, the deflection of the elevator is equal to the deflection on the control stick.  Before the reduction of down throw to in the elev, the elev and stick deflections were both 52-62 degrees.  Now that the Elev throw is 42-47 degrees so is the control stick.  

 

My goal is to regain the 52-62 degree deflection of the stick and maintain the 42-47 degree deflection of the Elev.  This will make the pilot move the stick more (with less force) in order to have the same amount of deflection in the Elev...thus desensitizing the elev.

 

After some CAD work I have determined the the 5/16 hole in the horn of part number 6-ds-2-2 will now be 92.5mm from the center of the rotational axis of 6-ds-2-opposeded to the original 130mm hole location indicated on print 6-DS-2.

larrycmcfarland(at)gmail.
Guest

Posted: Thu Feb 23, 2012 12:43 pm Post subject: Sensitive Elevator

Hi Andrew,

It sounds like you haven't completed your aircraft if drilling more holes

and such are being contemplated.   I 'd recommend you stay with the drawing.

The reduction you mention would result in load-changes that would put more

force on

 your control stick. This would cause you to lose the very control

sensitivity needed for the elevator.  Most people flying the Zeniths comment

that "the elevator has a lot of authority" and requires only small movements

during maneuvering, landing etc.  

Decreasing the stick throw while increasing the force seems contrary to your

need and perhaps a safety issue.



Respectfully,



Larry McFarland   601HDS at www.macsmachine.com

--

andrewtub

Joined: 01 Nov 2011
Posts: 18

Posted: Thu Feb 23, 2012 4:39 pm Post subject: Re: Sensitive Elevator

Larry,  What I am talking about is the opposite of what your concern is.



This change will require less stick force and have more stick travel.  The more stick travel will equal that of the original design while the elev deflection would meet the new specs.



Here's my deal.  I hear all these opinions about.. just fly it for 10-15 he's and you will get used to it.  Why should I get used to an undesirable trait of the plane when I have the opportunity to fix it now.  I will still have the required elev deflection and better input resolution.



AT

steve.freeman(at)syntaxds
Guest

Posted: Thu Feb 23, 2012 5:00 pm Post subject: Sensitive Elevator

<< an undesirable trait of the plane >>



Hmmmmmmmmmmmmmmmm



Steve



--

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Thu Feb 23, 2012 6:05 pm Post subject: Sensitive Elevator

It is NOT an undesirable trait.  What is undesirable is that 99% of the pilots out there learned on a SLOPPY C-152.  THAT DOES have undesirable characteristics.  What you suggest is that you could run out of stick.

 



On Thu, Feb 23, 2012 at 7:39 PM, andrewtub <andrewtub(at)yahoo.com (andrewtub(at)yahoo.com)> wrote:

[quote] --> Zenith-List message posted by: "andrewtub" <andrewtub(at)yahoo.com (andrewtub(at)yahoo.com)>

 

 Larry,  What I am talking about is the opposite of what your concern is.

 

 This change will require less stick force and have more stick travel.  The more stick travel will equal that of the original design while the elev deflection would meet the new specs.

 

 Here's my deal.  I hear all these opinions about.. just fly it for 10-15 he's and you will get used to it.  Why should I get used to an undesirable trait of the plane when I have the opportunity to fix it now.  I will still have the required elev deflection and better input resolution.

  

 AT

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=367098#367098

 

 

 

 

 

 

 

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 [b]

andrewtub

Joined: 01 Nov 2011
Posts: 18

Posted: Thu Feb 23, 2012 6:33 pm Post subject: Re: Sensitive Elevator

Seriously, I had no intention to fuel a fire.  It's just a mere suggestion to better a feature of the plane.  In allot of the reviews I read it is mentioned that the controls could be more balanced.  I get the same from three local zodiac pilots.  Why not try to improve when the opportunity is there?



In response to running out of stick...  the elev will still have full range of motion to the up and down stops specified by zenith.

davgray(at)sbcglobal.net
Guest

Posted: Fri Feb 24, 2012 3:42 am Post subject: Sensitive Elevator

Andrew



The controls on my 601XLB  require only small inputs during flight.  Even in 

a 60 degree bank it only requires two fingers for pressure and no trim 

adjustments.

Compare that to C & P models where the nose drops fast.  The relative 

displacement of the controls is pretty close.  The pressure for full aileron 

deflection at slow speed

is higher than the elevator with my hinge-less ailerons but not irritating. 

The overall impression is good.



Mine displays completely neutral stability which makes it feel nimble but 

does not self correct and return to level flight by itself when disturbed.

For that reason I did put Dynon's autopilot in.  It is easier to check a map 

or look up a frequency  without deviating from course and flight level.



Gary Ray  davgray(at)sbcglobal.net

Zenith 601XL-B, William Wynne Corvair 0.060 over, Roy's 5th bearing,

Mark's Falcon Heads, Marvel Schebler MA3-SPA Carburetor, 175 Hrs TT



--

Afterfxllc(at)aol.com
Guest

Posted: Fri Feb 24, 2012 7:21 am Post subject: Sensitive Elevator

If I read your email correct.....

  

 I have thought about doing the exact same thing for my next 2 planes I  build.... What you are suggesting makes sense because it would allow more  stick movement for the same elevator movement thus making the stick less  sensitive which is a good thing.

  

 Jeff

  

  In a message dated 2/24/2012 6:43:25 A.M. Eastern Standard Time,  davgray(at)sbcglobal.net writes:

 [quote]-->    Zenith-List message posted by: "Gary Ray"    <davgray(at)sbcglobal.net>



Andrew



The controls on my    601XLB  require only small inputs during flight.  Even in 

a 60    degree bank it only requires two fingers for pressure and no trim    

adjustments.

Compare that to C & P models where the nose drops    fast.  The relative 

displacement of the controls is pretty    close.  The pressure for full aileron 

deflection at slow speed

is    higher than the elevator with my hinge-less ailerons but not irritating.    

The overall impression is good.



Mine displays completely neutral    stability which makes it feel nimble but 

does not self correct and return    to level flight by itself when disturbed.

For that reason I did put Dynon's    autopilot in.  It is easier to check a map 

or look up a    frequency  without deviating from course and flight level.



Gary    Ray  davgray(at)sbcglobal.net

Zenith 601XL-B, William Wynne Corvair 0.060    over, Roy's 5th bearing,

Mark's Falcon Heads, Marvel Schebler MA3-SPA    Carburetor, 175 Hrs TT



--

rpf(at)wi.rr.com
Guest

Posted: Fri Feb 24, 2012 7:40 am Post subject: Sensitive Elevator

"making the stick less sensitive which is  a good thing"

  

 Not for me!  I love the way the stick feels.   Wouldn't change it for the world.

  

 Randy

 [quote]   ---

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