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XL main Spring gear placement

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chris Sinfield

Joined: 28 Nov 2006
Posts: 270
Location: Sydney Australia

Posted: Sun Apr 22, 2007 3:35 am Post subject: XL main Spring gear placement

OK Gang

Which way does the XL Main spring gear go?? Is it flat side to the raer or to the FWD side?



My photoguide shows flat side to the rear but the plans on page 6-3-G shows it with the arrow frwd. Now I have seen other pictures of it in both ways on other sites. But which is correct. I rang the factory but everyone was away at S&F. 



Does it make much difference? Is it better for Cof G to have it one way or the other?



Just an AUSSIE thought.. is FRWD short for Forward  or Flat RearWarDs??



I will have the Jab 3300 hanging on the nose.

Chris..

leinad

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

Posted: Sun Apr 22, 2007 3:47 am Post subject: Re: XL main Spring gear placement

Chris,

I'm not sure what version of the plans you have, but my plans show the flat side aft, and the angle side forward.  Same page 6G3.  My plans date 12/03.   I don't have tail dragger plans, but I believe they put they put the flat side forward.

Dan

_________________
Scratch building XL with Corvair Engine

davgray(at)sbcglobal.net
Guest

Posted: Sun Apr 22, 2007 4:08 am Post subject: XL main Spring gear placement

Chris



    The argument was :

    If you reverse the original placement it would move the wheels about 2"

forward making it easier to hold the nose wheel off after a landing during

the roll out and make it easier to lift the front wheel during takeoff.

    The Con is that you have to be more carefull during entry so you don't

rock backward onto the tail when somebody uses the boarding steps.



My gear is in the original more rearward position and it is not difficult

however the nosewheel does carry about 100 pounds more weight than either of

the main gear. It is definitely not the strongest part of the gear system.

In a normal landing I am not able to hold the nosewheel off the ground after

the mains touch down.



If I did it again, I would opt for gear placement that is more forward and

consider leaving the step off because I find it easier to mount the wing

from the front anyway.  I just sit on the main spar and slide rearward a

little to enter the cabin.  Less weight , less drag, less time to construct.



FWIW

Gary Ray



---

p.mulwitz(at)worldnet.att
Guest

Posted: Sun Apr 22, 2007 4:31 am Post subject: XL main Spring gear placement

Hi Chris,



My plans also show the flat side forward.  I believe this is the 

correct choice.  However, I doubt the difference is huge.



I have heard there are some times when the nose tends to hit the 

runway rather firmly on landings.  Moving the main gear a little 

forward by positioning the main gear spring with the flat side 

forward may reduce this tendency a little bit.  The only risk I can 

see with this approach is the possibility that a really aft CG might 

make the plane want to sit on its tail instead of the nose 

wheel.  This seems rather unlikely to be a condition where flight is possible.



I plan to install my gear with the flat side forward (soon, I hope).



Best regards,



Paul

XL Fuselage (nearly done)

At 03:35 AM 4/22/2007, you wrote:

 	  Quote: 	
		  

<chris_sinfield(at)yahoo.com.au>



OK Gang

Which way does the XL Main spring gear go?? Is it flat side to the 

raer or to the FWD side?



My photoguide shows flat side to the rear but the plans on page 

6-3-G shows it with the arrow frwd. Now I have seen other pictures 

of it in both ways on other sites. But which is correct. I rang the 

factory but everyone was away at S&F.



Does it make much difference? Is it better for Cof G to have it one 

way or the other?



Just an AUSSIE thought.. is FRWD short for Forward  or Flat RearWarDs??



I will have the Jab 3300 hanging on the nose.

Chris..

chris Sinfield

Joined: 28 Nov 2006
Posts: 270
Location: Sydney Australia

Posted: Sun Apr 22, 2007 4:48 am Post subject: Re: XL main Spring gear placement

Thanks for the replys already

I have the latest set of plans March 06 and its the normal version not Tail wheel.



With a Jab 3300 engine I believe the  Cof G is a little aft anyway is this correct? so it would be worse if the flat was FWD

Chris

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Sun Apr 22, 2007 4:55 am Post subject: XL main Spring gear placement

I believe the original plans called for the flat side to the rear.  

With a heavier engine, this puts the main wheels far enough behind  

the normal CG that it's a little bit hard to lift the nosewheel for  

takeoff or hold it off during landing. With my Subaru, for example, I  

have to apply  a lot of back pressure to rotate and as soon as the  

mains leave the ground, the plane wants to pitch up so I have to be  

prepared to release the back pressure right away. On landing, the  

reverse applies, the nose wants to drop rapidly as soon as the mains  

touch down. It's not a big problem but it's something to get used to.



I think the newer plans call for the flat side forward and I've seen  

that the LSAs being built at AMD have the gear this way. The photo  

guide probably reflects the older plans. I've done some calculations  

and I figure that putting the flat side forward would move the mains  

about four inches forward. With my airplane that would still put the  

mains far enough back that I could climb in and out without tilting  

the plane back on its tail, even with the plane loaded for gross  

weight and maximum aft CG. Two people might not be able to climb in  

at the same time though. It really wouldn't be a big deal to turn it  

around the other way, just pull off the mains, flip the spring  

around, re-mount the mains and then re-attach the brake lines the the  

spring. I've though about turning my main spring around but just  

haven't gotten around to it yet. If I were building it today knowing  

what I do now, I would build it with the flat side forward.

 	  Quote: 	
		   

 <chris_sinfield(at)yahoo.com.au>



 OK Gang

 Which way does the XL Main spring gear go?? Is it flat side to the  

 rear or to the FWD side?


	


-- 

Bryan Martin

N61BM, CH 601 XL,

RAM Subaru, Stratus redrive.

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

Tim Juhl

Joined: 21 Mar 2006
Posts: 488
Location: "Thumb" of Michigan

Posted: Sun Apr 22, 2007 6:19 am Post subject: Re: XL main Spring gear placement

The AMD model does have the gear turned flat side forward.  Remember that the factory built aircraft uses the 0-200 which weighs in around 210-220 lbs I believe.  The Jabiru installed weight is 178 lbs.  Other differences include whether you use a wood or metal prop and how heavy you load up the instrument panel.  15 gal vs 12 gal tanks can make a difference too. 



Mark Townsend of CanZac told me that aircraft with the gear flat side forward have more of a tendancy to ground the tail when you climb on the step.  Contrast that to a slightly ground-hugging takeoff roll and I think I'll try my Jab equipped XL with the gear flat side rearward.  



I carefully examine all the comments from those already flying for gems of wisdom so keep them coming 



Tim

_________________
______________
CFII
Champ L16A flying
Zodiac XL - Jabiru 3300A
Almost done! It'll fly in spring!

rstone4(at)hot.rr.com
Guest

Posted: Sun Apr 22, 2007 8:19 am Post subject: XL main Spring gear placement

Members,

     I am running a Jabiru 3300 engine in my Zodiac601XL and it does the 

same thing, that is requires more that usual back pressure to rotate and 

when it does the nose pitches up sharply and requires immediate forward 

pressure to prevent stall.  I was told this was an easy airplane to fly but 

this is not true.  Every spam can I ever flew prior to flying the ZodiacXL 

was much easer than this one.



Tracy Stone

---

craig(at)craigandjean.com
Guest

Posted: Sun Apr 22, 2007 8:36 am Post subject: XL main Spring gear placement

 	  Quote: 	
		   I am running a Jabiru 3300 engine in my Zodiac601XL and it does the same

thing
	




Which way does your gear face, Tracy?



-- Craig

planecrazydld(at)yahoo.co
Guest

Posted: Sun Apr 22, 2007 9:24 am Post subject: XL main Spring gear placement

So if a person is building from scratch, would there be any sense in making the spring symmetrical? That way the effects would be half as severe for either condition. I do know that I do not want the plane to be difficult to unstick - or for it to zoom climb the instant of breaking ground...



Bryan Martin <bryanmmartin(at)comcast.net> wrote: 	  Quote: 	
		   --> Zenith-List message posted by: Bryan Martin 



I believe the original plans called for the flat side to the rear.  

With a heavier engine, this puts the main wheels far enough behind  

the normal CG that it's a little bit hard to lift the nosewheel for  

takeoff or hold it off during landing. With my Subaru, for example, I  

have to apply  a lot of back pressure to rotate and as soon as the  

mains leave the ground, the plane wants to pitch up so I  have to be  

prepared to release the back pressure right away. On landing, the  

reverse applies, the nose wants to drop rapidly as soon as the mains  

touch down. It's not a big problem but it's something to get used to.



I think the newer plans call for the flat side forward and I've seen  

that the LSAs being built at AMD have the gear this way. The photo  

guide probably reflects the older plans. I've done some calculations  

and I figure that putting the flat side forward would move the mains  

about four inches forward. With my airplane that would still put the  

mains far enough back that I could climb in and out without tilting  

the plane back on its tail, even with the plane loaded for gross  

weight and maximum aft CG. Two people might not be able to climb in  

at the same time though. It really wouldn't be a big deal to turn it  

around the other way, just pull off the mains, flip the spring  

around, re-mount the  mains and then re-attach the brake lines the the  

spring. I've though about turning my main spring around but just  

haven't gotten around to it yet. If I were building it today knowing  

what I do now, I would build it with the flat side forward.

	


  Dave Downey

  Harleysville (SE) PA

  Zodiac 601XL/Corvair?

           Ahhh...imagining that irresistible "new car" smell?

 Check out [url=http://us.rd.yahoo.com/evt=48245/*http://autos.yahoo.com/new_cars.html;_ylc=X3oDMTE1YW1jcXJ2BF9TAzk3MTA3MDc2BHNlYwNtYWlsdGFncwRzbGsDbmV3LWNhcnM-]new cars at Yahoo! Autos.[/url]  [quote][b]

tonyplane(at)bellsouth.ne
Guest

Posted: Sun Apr 22, 2007 10:26 am Post subject: XL main Spring gear placement

I agree.  One of the things I wish I had know  about was the gear reversal, before I installed my gear. 

 I have this caution in my POH.  Found this out  in flight test when I set it up for a high speed (about 65 kt) landing with full  flaps and rotated nose high but did not stop sink rate.   Not a  problem landing slow with full flaps or low or"high" speed with no flaps with  sink rate arrested, but more forgiving at high  speed with no flaps.

  

 

 CAUTION<?xml:namespace  prefix = o ns = "urn:schemas-microsoft-com:office:office"  /> 

 

 WATCH SINK RATE AND AIR  SPEED:  with the landing gear geometry  of 493TG, a High sink rate combined with High air speed at touch down will  result in the nose gear hitting the runway HARD… and bouncing the airplane  airborne in a nose high attitude.   IF THIS HAPPENS – GO AROUND or initiate a BOUNCE RECOVERY!   Pilot  Induced Oscillation (PIO) can result under this condition if landing is  attempted. 

    Tony Graziano

 601XL/Jab3300; N493TG 234 hrs.

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

             Subject:              Re: XL main Spring gear        placement        From:              Bryan Martin (bryanmmartin(at)comcast.net ([email]bryanmmartin(at)comcast.net?subject=Re:%20XL%20main%20Spring%20gear%20placement&replyto=7C6CF49B-80E6-4C1A-A2D7-0F9DDCDDEDE6(at)comcast.net[/email]))        Date:              [b]Sun Apr 22 - 5:55        AM[/b]  	  Quote: 	
		   	  Quote: 	
		  I believe the original plans called for the flat side to the rear.  

With a heavier engine, this puts the main wheels far enough behind  

the normal CG that it's a little bit hard to lift the nosewheel for  

takeoff or hold it off during landing. With my Subaru, for example, I  

have to apply  a lot of back pressure to rotate and as soon as the  

mains leave the ground, the plane wants to pitch up so I have to be  

prepared to release the back pressure right away. On landing, the  

reverse applies, the nose wants to drop rapidly as soon as the mains  

touch down. It's not a big problem but it's something to get used to.



I think the newer plans call for the flat side forward and I've seen  

that the LSAs being built at AMD have the gear this way. The photo  

guide probably reflects the older plans. I've done some calculations  

and I figure that putting the flat side forward would move the mains  

about four inches forward. With my airplane that would still put the  

mains far enough back that I could climb in and out without tilting  

the plane back on its tail, even with the plane loaded for gross  

weight and maximum aft CG. Two people might not be able to climb in  

at the same time though. It really wouldn't be a big deal to turn it  

around the other way, just pull off the mains, flip the spring  

around, re-mount the mains and then re-attach the brake lines the the  

spring. I've though about turning my main spring around but just  

haven't gotten around to it yet. If I were building it today knowing  

what I do now, I would build it with the flat side forward.

 	  Quote: 	
		   <chris_sinfield(at)yahoo.com.au ([email]chris_sinfield(at)yahoo.com.au?subject=Re:%20XL%20main%20Spring%20gear%20placement&replyto=7C6CF49B-80E6-4C1A-A2D7-0F9DDCDDEDE6(at)comcast.net[/email])>



 OK Gang

 Which way does the XL Main spring gear go?? Is it flat side to the  

 rear or to the FWD side?


	




-- 

Bryan Martin

N61BM, CH 601 XL,

RAM Subaru, Stratus redrive.

	
	


   [quote][b]

taffy0687(at)yahoo.com
Guest

Posted: Sun Apr 22, 2007 10:51 am Post subject: XL main Spring gear placement

my thoughts only--- I am building from plans -- I thought the same as Dave, splitting the difference. But,   I decided to go "straight (flat) part of bar forward.  MY reasoning, all else being ok--- keep as much weight as possible off from the nose gear assembly (and stay within the design).   Why?  nose gear strut has direct linkage to rudder pedals- crosswind landings.

  Fritz



David Downey <planecrazydld(at)yahoo.com> wrote:

  [quote]So if a person is building from scratch, would there be any sense in making the spring symmetrical? That way the effects would be half as severe for either condition. I do know that I do not want the plane to be difficult to unstick - or for it to zoom climb the instant of breaking ground...



Bryan Martin <bryanmmartin(at)comcast.net> wrote:   	  Quote: 	
		  --> Zenith-List message posted by: Bryan Martin 



I believe the original plans called for the flat side to the rear. 

With a heavier engine, this puts the main wheels far enough behind 

the normal CG that it's a little bit hard to lift the nosewheel for 

takeoff or hold it off during landing. With my Subaru, for example, I 

have to apply a lot of back pressure to rotate and as soon as the 

mains leave the ground, the plane wants to pitch up so I have to be 

prepared to release the back pressure right away. On landing, the 

reverse applies, the nose wants to drop rapidly as soon as the mains 

touch down. It's not a big problem but it's something to get used to.



I think the newer plans call for the flat side forward and I've seen 

that the LSAs being built at AMD have the gear this way. The photo 

guide  probably reflects the older plans. I've done some calculations 

and I figure that putting the flat side forward would move the mains 

about four inches forward. With my airplane that would still put the 

mains far enough back that I could climb in and out without tilting 

the plane back on its tail, even with the plane loaded for gross 

weight and maximum aft CG. Two people might not be able to climb in 

at the same time though. It really wouldn't be a big deal to turn it 

around the other way, just pull off the mains, flip the spring 

around, re-mount the mains and then re-attach the brake lines the the 

spring. I've though about turning my main spring around but just 

haven't gotten around to it yet. If I were building it today knowing 

what I do now, I would build it with the flat side forward.

	


    Dave Downey

  Harleysville (SE) PA

  Zodiac        Ahhh...imagining that irresistible "new car" smell?

 Check out [url=http://us.rd.yahoo.com/evt=48245/*http://autos.yahoo.com/new_cars.html;_ylc=X3oDMTE1YW1jcXJ2BF9TAzk3MTA3MDc2BHNlYwNtYWlsdGFncwRzbGsDbmV3LWNhcnM-]new cars at Yahoo! Autos.[/url]  [quote][b]

afterfxllc(at)aol.com
Guest

Posted: Sun Apr 22, 2007 11:23 am Post subject: XL main Spring gear placement

At our hanger we have 3 601's 1 has a Rotax and 1 has a O-235 125HP conversion and 1 has the corvair and all have the flat of the mains aft. and they all fly fine. The plans show the flat aft also.

 

   

  

 --

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Sun Apr 22, 2007 3:16 pm Post subject: XL main Spring gear placement

I think the plane was originally designed for the Rotax, which is a  

fairly light engine. With any other engine, I don't think there will  

be any problem with just building the gear to plans and mounting it  

flat side forward. In any case, with the flat side aft, it isn't a  

serious problem, just different. I got used to it fairly quickly.



On Apr 22, 2007, at 1:23 PM, David Downey wrote:



 	  Quote: 	
		   So if a person is building from scratch, would there be any sense  

 in making the spring symmetrical? That way the effects would be  

 half as severe for either condition. I do know that I do not want  

 the plane to be difficult to unstick - or for it to zoom climb the  

 instant of breaking ground...



 Bryan Martin <bryanmmartin(at)comcast.net> wrote: --> Zenith-List  

 message posted by: Bryan Martin



 I believe the original plans called for the flat side to the rear.

 With a heavier engine, this puts the main wheels far enough behind

 the normal CG that it's a little bit hard to lift the nosewheel for

 ...


	




-- 

Bryan Martin

N61BM, CH 601 XL,

RAM Subaru, Stratus redrive.

do not archive.

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

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