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Toe in Toe Out

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lcfitt(at)sbcglobal.net
Guest

Posted: Sat Mar 11, 2006 11:14 am Post subject: Toe in Toe Out

The following is a copy of a post sent 2 Jan 1997 to the old 

kitfox(at)lists.Colorado.EDU, by Graham E. Laucht, a name many of the old 

timers on the list will remember, and a wonder of knowledge.



The post is in response to the following question:



 	  Quote: 	
		  Im looking at my wheel alignment (classic 4) and see about 6 inches toe in 

measured at the >elevator.


	


 	  Quote: 	
		  How much miss alignment is acceptable and what are the effects besides tire 

wear. I don't want >to start using a crow bar to spring the wheels of it 

isn't necessary.


	


_____



As a general rule toe in on a taildragger (wheel rims closer together at the 

front) is strongly destabilising and therefore toe out (wheels rims further 

apart at the front) is less unstable. In simple terms the risks associated 

with ground loops etc. are greater with toe in. They still don't go away, 

however. The position is different on a trike which in any case is strongly 

stable to start with due to the CG being ahead of the main gear.



The actual angles are very much determined by the CG position, it's position 

with relationship to the main gear and to the masses disposed about the CG 

but again a general rule of thumb between 1 and 2 degrees of total toe out 

is desirable but no more. Some types are even set up neutral and some even 

assymetric to compensate for P effect. If you have heavier than design 

engine installation the book figure may be incorrect. Likewise additional 

tail weight, batteries up the back end etc. all conspire to alter the 

dynamics and generally call for less easily breaking tailwheels.



Taildraggers that are particularly skittish on the ground can often be found 

to have landing gear damage though of course there are other possible 

explanations.



One of the main reasons tailwheel locking was employed in large tailwheel 

aircraft like the DC3 was to do with amount of mass ahead of the CG as they 

offered little corrective restraint from a yaw or skid or from assymetric 

power application. Wheel 'em on , wheel 'em off being the motto.



Loose tailwheels, broken or weak steering springs, incorrect castor angle, 

saggy springs all contribute to the problem.



NB the effect of one soft tyre on a dragger is exactly the same as toe in, 

as I found out the other day, especially when it's on the windward side of 

the crosswind. A bystander actually believed I had cleared the active runway 

quickly on purpose, little did he know the driver was ten milliseconds 

behind his demented supermarket trolley.



-



Graham E. Laucht

torgemor(at)online.no
Guest

Posted: Mon Mar 13, 2006 4:50 pm Post subject: Toe in Toe Out

Hi there,

A real good reference, Graham E. Launch.

Here is some more "web" info about the problem (even mention our kind of 

AC, the Kitfox).

http://www.bluemaxul.com/rans/messages/249.html

Then the great "toe debate":  A good one!! It's RC, but the "practical" 

theory is just as good as the real thing.

http://rcmf.co.uk/articles/toe-debate.html

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

Remember our cars, this is where all the "advanced" steering theory is 

developed.

If we have too much toe in (no servo here), the steering wheel will become 

light, -also, during turn, the car tends to accelerate the turn by 

itself!  Have you ever tried such a car?

Now the other way, to much toe out. This time the steering wheel become 

very heavy and the car want to go back straight forward.

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

The gear should be toe out for a tail dragger and toe in for a nose wheel 

AC. The amount of toe out for the tail dragger should be very small, like 

0 to 0.5 degrees. The toe in for the mains in a nose wheel AC is not as 

critical but should be small in order to reduce the rolling resistance on 

takeoff.

Some more:

The toe angle must be measured with tail up (in level), and with proper 

loading.

With to much toe out, the wheels tend to spread and stretching the rubber 

feather.  What about take off at max. gross in an rough out field 

operation.

Anyhow, did not SS said toe in ???

Cheers

Torgeir.

On Sat, 11 Mar 2006 11:11:19 -0800, Lowell Fitt <lcfitt(at)sbcglobal.net> 

wrote:

 	  Quote: 	

 The following is a copy of a post sent 2 Jan 1997 to the old

 kitfox(at)lists.Colorado.EDU, by Graham E. Laucht, a name many of the old

 timers on the list will remember, and a wonder of knowledge.

 The post is in response to the following question:

> Im looking at my wheel alignment (classic 4) and see about 6 inches toe 

> in

> measured at the >elevator.

> How much miss alignment is acceptable and what are the effects besides 

> tire

> wear. I don't want >to start using a crow bar to spring the wheels of it

> isn't necessary.

 _____

 As a general rule toe in on a taildragger (wheel rims closer together at 

 the

 front) is strongly destabilising and therefore toe out (wheels rims 

 further

 apart at the front) is less unstable. In simple terms the risks 

 associated

 with ground loops etc. are greater with toe in. They still don't go away,

 however. The position is different on a trike which in any case is 

 strongly

 stable to start with due to the CG being ahead of the main gear.

 The actual angles are very much determined by the CG position, it's 

 position

 with relationship to the main gear and to the masses disposed about the 

 CG

 but again a general rule of thumb between 1 and 2 degrees of total toe 

 out

 is desirable but no more. Some types are even set up neutral and some 

 even

 assymetric to compensate for P effect. If you have heavier than design

 engine installation the book figure may be incorrect. Likewise additional

 tail weight, batteries up the back end etc. all conspire to alter the

 dynamics and generally call for less easily breaking tailwheels.

 Taildraggers that are particularly skittish on the ground can often be 

 found

 to have landing gear damage though of course there are other possible

 explanations.

 One of the main reasons tailwheel locking was employed in large tailwheel

 aircraft like the DC3 was to do with amount of mass ahead of the CG as 

 they

 offered little corrective restraint from a yaw or skid or from assymetric

 power application. Wheel 'em on , wheel 'em off being the motto.

 Loose tailwheels, broken or weak steering springs, incorrect castor 

 angle,

 saggy springs all contribute to the problem.

 NB the effect of one soft tyre on a dragger is exactly the same as toe 

 in,

 as I found out the other day, especially when it's on the windward side 

 of

 the crosswind. A bystander actually believed I had cleared the active 

 runway

 quickly on purpose, little did he know the driver was ten milliseconds

 behind his demented supermarket trolley.

 -

 Graham E. Laucht

-- 

Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

lcfitt(at)sbcglobal.net
Guest

Posted: Mon Mar 13, 2006 6:44 pm Post subject: Toe in Toe Out

Torgeir,



Thanks a bunch for the links.  Thanks!!



Lowell

---

bnn(at)nethere.com
Guest

Posted: Mon Mar 13, 2006 10:42 pm Post subject: Toe in Toe Out

OK. You've convinced me that I have to get rid of the toe-in. (About 3/4 

degree total.) I have covered tube gear. Has anybody bent their covered 

tube gear without removing the covering? I really dread getting a wrinkle.

Guy Buchanan

K-IV 1200 / 582 / 99.9% done, thanks mostly to Bob Ducar.

bmwebb(at)cox.net
Guest

Posted: Tue Mar 14, 2006 3:54 am Post subject: Toe in Toe Out

I'm convinced, and would like to know, as well.



Bradley



--

Bill Willyard

Joined: 10 Jan 2006
Posts: 34
Location: Grandville, Michigan U.S.A.

Posted: Tue Mar 14, 2006 4:22 am Post subject: Toe in Toe Out

--

_________________
Bill Willyard
Classic IV 912UL

morid(at)northland.lib.mi
Guest

Posted: Tue Mar 14, 2006 4:43 am Post subject: Toe in Toe Out

I've never bent one myself, but this is an old and very well covered topic.

One thing that you need to be careful of when you use your cheater bar is to

twist the whole gear unit, not bend the axle.  With some forethought it

shouldn't be difficult to come up with something that will work.

Deke

[quote] 



 I'm convinced, and would like to know, as well.



 Bradley



 --

lcfitt(at)sbcglobal.net
Guest

Posted: Tue Mar 14, 2006 6:51 am Post subject: Toe in Toe Out

Guy,



When I did mine, most of the bend was in the axle.  I secured the airplane 

per the article in the Kitfox Times and fitted a piece of pipe over a copper 

pipe spacer to  protect the threads on the axle and bent.  I had to shim the 

brake calipers afterwords to get them to run parallel to the rotors.  Others 

have put a large wrench on the weldment and bent the weldment..  I believe 

mine was  covered at the time.



I made a jig that secured the tail to the hangar floor with anchor bolts.  I 

still have it and it is available to anyone interested, for shipping.



Lowell

---

msm_9949(at)yahoo.com
Guest

Posted: Tue Mar 14, 2006 8:18 am Post subject: Toe in Toe Out

Whoa up a minute Guy. 3/4 of a degree is not much. That's practically neutral. IMHO you'll do no more damage to your fox by waiting until you see how it handles on the ground before reefing on those weldments. You may decide to leave it alone.

   

  I have about 1 degree of toe in on my model 2. I can't say it's the most forgiving taildragger I've ever landed, but it really ain't that bad. At least not on grass. I might change my mind this Spring when I start trying pavement.

   

  Start on grass and skip high speed taxi tests entirely. In my experience, that part of the envelope is no place to get acquainted with your airplane. 

   

  Got my flak jacket on, so have at me.

  

Guy Buchanan <bnn(at)nethere.com> wrote:

  



OK. You've convinced me that I have to get rid of the toe-in. (About 3/4 

degree total.) I have covered tube gear. Has anybody bent their covered 

tube gear without removing the covering? I really dread getting a wrinkle.

Guy Buchanan

K-IV 1200 / 582 / 99.9% done, thanks mostly to Bob Ducar. 





Marco Menezes

Model 2 582 N99KX

		

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

7suds(at)Chartermi.net
Guest

Posted: Tue Mar 14, 2006 2:32 pm Post subject: Toe in Toe Out

All,

Have been following the toe in /out thing and when I built my 4 I had tube 

gear and I used the cheater pipe over the axle method to set my gear angle, 

it did not take much to get there, I do not remember how much it was out, 

not much as I recall, but I set them slightly out and vertical, no regrets, 

landed on everything with it. My 2-Cents worth, and starting on grass is a 

good idea, but if your track is off it will be a different ride on the 

pavement.

Lloyd



---

bnn(at)nethere.com
Guest

Posted: Tue Mar 14, 2006 4:34 pm Post subject: Toe in Toe Out

At 08:15 AM 3/14/2006, you wrote:

 	  Quote: 	
		  Whoa up a minute Guy. 3/4 of a degree is not much.


	


Thanks Marco, Bill and the rest who replied. I think Marco's right, 

especially since I don't intend to do the first flight, but to let an 

experienced Kitfox flyer do it. If they think it squirrelly, it won't take 

long to alter. Later I can ground loop it myself! =-O

Guy Buchanan

K-IV 1200 / 582 / 99.9% done, thanks mostly to Bob Ducar.

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