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Toe-in, was Bungee replacement

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Fox5flyer
Guest

Posted: Mon Dec 31, 2007 4:21 am Post subject: Toe-in, was Bungee replacement

Steve, with all due respect, this is incorrect and this type of setup will 

cause bent airplanes.  It might be good for cars, but not airplanes. 

Picture yourself with a small crosswind that causes you to veer slightly to 

the right.  The inside wheel is already turned left which will exacerbate 

the turn.  The more toe-in the more squirrely the airplane will be.  If, 

when level, the airplane has toe-in it will have more in the three point 

attitude which partly why people lose control as they start to let the tail 

down from the two point attitude.  Add to this the loss of airflow over the 

rudder and you have a ground loop.

The best is slightly toe-out when in level attitude.  This will put the 

wheels in a neutral attitude when in three point.  Of course, there are lots 

of airplanes out there with a little toe-in and some with more than a 

little, and they are flyable, but are more difficult to keep straight when 

in three point, especially when a swerve starts.

Deke Morisse

Mikado Michigan

S5/Subaru/CAP 355+ TT

"Nothing will ever be attempted, if all possible objections must first be 

overcome".- Samuel Johnson



[quote]

 Gary

 I think that the toe out situation is far worse than the toe in .Just my 

 .02

 Steve



 --

clint_bazzill(at)hotmail.
Guest

Posted: Mon Dec 31, 2007 9:41 am Post subject: Toe-in, was Bungee replacement

I might as well join in this toe-in toe-out food fight.  My personnel feelings someone needs and excuse for not being able to hold their aircraft staight down the runway.  The wheels are only a few inches from the CG and the tailwheel and rudder are many many feet back.  The little effect that you have from the toe-in toe-out I am sure would take a superman pilot to tell.  Its like driving a car backwards at 40-50 MPH and saying that the wheel alignment is off because its hard to hold straight.  Clint

[quote] From: fox5flyer(at)idealwifi.net

 To: kitfox-list(at)matronics.com

 Subject: Toe-in, was Bungee replacement

 Date: Mon, 31 Dec 2007 07:19:51 -0500

 --> Kitfox-List message posted by: "fox5flyer" <fox5flyer(at)idealwifi.net>

 Steve, with all due respect, this is incorrect and this type of setup will 

 cause bent airplanes. It might be good for cars, but not airplanes. 

 Picture yourself with a small crosswind that causes you to veer slightly to 

 the right. The inside wheel is already turned left which will exacerbate 

 the turn. The more toe-in the more squirrely the airplane will be. If, 

 when level, the airplane has toe-in it will have more in the three point 

 attitude which partly why people lose control as they start to let the tail 

 down from the two point attitude. Add to this the loss of airflow over the 

 rudder and you have a ground loop.

 The best is slightly toe-out when in level attitude. This will put the 

 wheels in a neutral attitude when in three point. Of course, there are lots 

 of airplanes out there with a little toe-in and some with more than a 

 little, and they are flyable, but are more difficult to keep straight when 

 in three point, especially when a swerve starts.

 Deke Morisse

 Mikado Michigan

 S5/Subaru/CAP 355+ TT

 "Nothing will ever be attempted, if all possible objections must first be 

 overcome".- Samuel Johnson

 >

 > Gary

 > I think that the toe out situation is far worse than the toe in .Just my 

 > .02

 > Steve

 >

 > --

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Mon Dec 31, 2007 11:32 am Post subject: Re: Toe-in, was Bungee replacement

 	  Quote: 	
		  My personnel feelings someone needs and excuse for not being able to hold their aircraft staight down the runway. 	




Clint GREAT ANSWER   !!  I mentioned the same thing on this  the other day on Grove hear > http://forums.matronics.com/viewtopic.php?t=37513



Grove gear looks good but VERY expensive and extra weight over the bungee. A personal choice aesthetically , but No substitute to taildragger training

And for the record, my bungees are only wrapped 5 turns rather than 6 and sloppy and old .......  They are about 1 " from the stops empty.  I have taken 6 guys in the last few days flying all over 200 lbs and I weigh 210 lbs as well.  I am not sure what all the fuss is about.



Also, if you are measuring toe in or out-- HOW MUCH IS A DEGREE ?  

I would measure toe only one way......... by the differance in distance between the front and rear of the tires ........   you can measure sidewalls but the BEST WAY is to scribe a line in the tire as it is spun to get the actual centerline. You could use chalk or paint to scribe it --not the ACTUAL TIRE   DUH !! 



PS  Clint --   did i miss the VG report that you did ?

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propellerdesign(at)tele2.
Guest

Posted: Mon Dec 31, 2007 12:42 pm Post subject: Toe-in, was Bungee replacement

Dave and all.



one degree is 1,7455 at a distance of 100, inch, meter or bananas work the 

same.



Earlier today I was reading about the Silent single seater , they said zero 

or one half degree. OUT with plane in level position.



Jan

---

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Mon Dec 31, 2007 12:49 pm Post subject: Re: Toe-in, was Bungee replacement

Jan, that was my point -- 

how does everyone actually measure there toe  in degrees.  



Gotta all use the same distance 



 	  Quote: 	
		  Dave and all. 



one degree is 1,7455 at a distance of 100, inch, meter or bananas work the 

same. 



Earlier today I was reading about the Silent single seater , they said zero 

or one half degree. OUT with plane in level position. 



Jan

Fox5flyer
Guest

Posted: Mon Dec 31, 2007 2:02 pm Post subject: Toe-in, was Bungee replacement

Somewhere in the archives is Skystar's/Denny's instructions on a step by 

step procedure for setting/checking/adjusting the gear.  It's probably a 

service bulletin and I thought I had it here, but can't find it.  It's just 

one page so if anyone has it can you please copy/paste it for us?

Deke Morisse

Mikado Michigan

S5/Subaru/CAP 355+ TT

"Nothing will ever be attempted, if all possible objections must first be 

overcome".- Samuel Johnson



---

lcfitt(at)sbcglobal.net
Guest

Posted: Mon Dec 31, 2007 2:57 pm Post subject: Toe-in, was Bungee replacement

I sort of agree with Clint, but  in saying that, there was this same thread 

while I was building and I used the method recommended by Skystar in their 

service bulletin to adjust my gear to a little bit out from parallel on each 

leg.  I also had no ground handling problems nor did I get assymetrical wear 

on the tires.  I did have a friend that early on had so much problem with 

his ground handling that he dumped his Model IV - onto someone else.  My 

guess it was wheel alignment.  My friends Lancair had horrible tire wear 

problems and a quick measurement and shims solved that.



I must say here, though, that all these little beauties are home made and 

the factory that assembled the weldments was not really the picture of 

mechanical precision.  For this reason, I doubt it can be said that there 

can never be a need for a bit of tweaking, or for that matter that since 

mine tracks fine your problems must be in your technique.  I do agree that 

the worst handling airplane can be managed quite well with an expert pilot, 

but what's the point in that?  It sort of reminds me of the local CFI that 

continually bragged about his expert off field landing after he ran out of 

gas (0n a 20 minute flight).



Regarding how to determine alignment angle.  The Skystar instructions, as I 

recall, were to drop bobs from the tail wheel mounting bolt and the midline 

between the wheels and mark a chock line on the floor representing the 

center line of the fuselage.  From here it gets a little more interesting. 

Some will use the outside of the tire as the wheel longitudinal index 

points.  Some will use the brake rotor with standoffs on the straight edge 

to clear the wheel contour.  One guy I talked to would put a length of white 

masking tape on the exact back of the tire, mark the center of the tire and 

the floor directly under the axle.  measure the distance beetween the two 

marks.  Then he rolled his airplane forward until the tape and mark was 

exactly in front of the tire, again marking the floor under the axle.  He 

again measured the distance between the marks.  This method gives overall 

toe in or tow out, but doesn't identify which gearleg is the major culprit. 

It is an easy way to do a quick check, however, but I guess it could be used 

if the center line remained the centerline after the movement.



When I did it, I removed the wheels and used a square against the axle. 

Once these measurements are determined with appropriate marks on the floor. 

Measure a distance forward, draw a perpendicular line across the tracks of 

the wheels and determine the distance between the center line and the 

reference line for each wheel and it will indicate toe in or out and the 

actual angle is easy to determine with a drawing program like Turbo Cad. 

Just subtract the distence between the center line and each wheel index 

point from each measurement and you get nice little triangles which can be 

drawn into the drawing program and using the angle tool, it will give the 

angles.  The angles don't actually mean a lot unless you have the grove gear 

and need to buy a shim.



With the tube gear the plan is to use a padded length of pipe and with the 

tail secured, muscle the gear leg into alighment.   What I found is the the 

gear weldment is a pretty tough structure and the correction was solely in 

the axle - it bent, requiring shims (a washer or two under the brake caliper 

to bring that unto alignment with the axle.



Lowell



---

propellerdesign(at)tele2.
Guest

Posted: Mon Dec 31, 2007 3:46 pm Post subject: Toe-in, was Bungee replacement

Ones when I had my car at the Swedish Car Inspection, the guy there tried to 

measure the toe-in on the rear wheel, with use of a libelle! was interesting 

to watch him for a long time before he finely come to the conclusion I had 

from the beginning, that it would not work out. 



Happy New Year

Jan

---

57_kid

Joined: 27 Aug 2006
Posts: 50

Posted: Mon Dec 31, 2007 5:38 pm Post subject: Toe-in, was Bungee replacement

--

57_kid

Joined: 27 Aug 2006
Posts: 50

Posted: Mon Dec 31, 2007 5:53 pm Post subject: Toe-in, was Bungee replacement

Gary In my experience with aircraft and autos when you speak of toe in you

are talking about 1/16 of an inch toe in when the toe is out the wheels get

really squirley once the aircraft moves forward , In my experience as an A&P

mechanic to much of either on will cause a handling problem, you also need

to keep in mind that the friction of the wheels against the ground will pull

them rearward and if you have a little toe in they will be closer to neutral

, but with a toe out situation they will have a negative number, my model 5

has about 1/16 inch toe in and handles great  I have around 600hrs on it and

the tires show very little wear  Like I said just my  .02



--

57_kid

Joined: 27 Aug 2006
Posts: 50

Posted: Mon Dec 31, 2007 6:11 pm Post subject: Toe-in, was Bungee replacement

everyone ,

I'm not wanting to argue about the toe in or out  I'm just stating what

worked for me. since you are all the manufactures you can do whatever you

want and that is the GREAT part of building your own aircraft.   the Kitfox

is a very well designd aircraft and fits the homebuilder very well

Steve



--

avidfox

Joined: 03 Apr 2007
Posts: 87

Posted: Mon Dec 31, 2007 6:25 pm Post subject: Toe-in, was Bungee replacement

All this about alignment....  I assume you all have the main gear tires sitting on 'grease plates' at a loaded weight when you start taking measurements. Hmmm.....?

 

 

 [quote] [b]

propellerdesign(at)tele2.
Guest

Posted: Tue Jan 01, 2008 1:51 am Post subject: Toe-in, was Bungee replacement

Correct on cars, with rear drive, toe-in, front wheel drive, toe-out - when 

driving, the wheels will be pulling them self forward/in.



On Tail-dragger, neutral or toe-out

Tri gear toe-in



In a turn it is the wheel that get most load that "steer" meaning it is the 

outer wheel in a turn.

The wheel that get the least load in a turn is as always the spare wheel.



But something to think about is also the camber, if the wheels is leaning 

out or in, they want to turn that way, having same effect as toe-in/out, 

this can be compensated for by toe-in/out on some aircraft types.



Jan

---

Fox5flyer
Guest

Posted: Tue Jan 01, 2008 5:49 am Post subject: Toe-in, was Bungee replacement

Good post Lowell.  Well said and very helpful.

Deke Morisse

Mikado Michigan

S5/Subaru/CAP 355+ TT

"Nothing will ever be attempted, if all possible objections must first be 

overcome".- Samuel Johnson



do not archive



 	  Quote: 	
		   ...snip

 I must say here, though, that all these little beauties are home made and 

 the factory that assembled the weldments was not really the picture of 

 mechanical precision.  For this reason, I doubt it can be said that there 

 can never be a need for a bit of tweaking, or for that matter that since 

 mine tracks fine your problems must be in your technique.  I do agree that 

 the worst handling airplane can be managed quite well with an expert 

 pilot, but what's the point in that?  It sort of reminds me of the local 

 CFI that continually bragged about his expert off field landing after he 

 ran out of gas (0n a 20 minute flight).

snip...

Joel

Joined: 06 Oct 2006
Posts: 57
Location: Bremerton, WA USA

Posted: Tue Jan 01, 2008 10:27 am Post subject: Re: Toe-in, was Bungee replacement

An inexpensive laser level with a magnetic base attached to the brake disc allows for very accurate measurement of toe-in or toe-out. Load your aircraft to typical flying weight and roll it forward to 100 inches from a wall. Compare the difference between the distance between the discs and the distances between the spots on the wall to determine your alignment. My bungee gear ended up at < 1/2 degree toe-in and tracked very well.

_________________
Joel Mapes Kitfox 5 912 ULS Aerocomp amphibs

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Wed Jan 02, 2008 3:48 am Post subject: Re: Toe-in, was Bungee replacement

 	  Quote: 	
		  But something to think about is also the camber, if the wheels is leaning 

out or in, they want to turn that way, having same effect as toe-in/out, 

this can be compensated for by toe-in/out on some aircraft types. 	




back in the '70s I spent the first 3 years of my apprenticeship for Autos/Trucks doing alignments.   The car will pull to high camber ( wheel leaning out at top)

and to low caster(caster is the angle in the kingpin or balljoints, only relevant here on tailwheels and my  Amphib nose gear )



If your wheels spin ture with no wobble measure the inside of the wheel both from and rear at  the same height. If not spin hte wheel and make a mark in it as it spins. You will want to see from zero to 1/8"  toe out on your taildrager.   I use inches as most can likely comprehend  that over degrees as it makes it far easier for most. 

Remember this  is not rocket science, it just a simple measurement.



Now I might confess I have never measured my  Toe in as They look ok to me and seem to handle ok.   BUT  I will say that after i put on the King fox tires  , my first asphault landing was ona a paved strip about 30' wide with  near 90 degree crosswind wigh winds 10 to 15 knots.   I found that I really had to be on top of the rudder  moreso that with my previous 16.5 x 8  Gold cart type tires.  



I have skis on now  and for Kicks I will measure them today .

msm_9949(at)yahoo.com
Guest

Posted: Wed Jan 02, 2008 8:52 am Post subject: Toe-in, was Bungee replacement

FWIW, my advice to anyone getting ready to bend bungee gear weldments to "correct" a minor toe-in/out condition is, don't. I agree with those who advise that such conditions really do not have any noticible effect on ground handling characteristics. At least that's been my experience.

   

  There was alot of discussion on this two or three years ago. Because I was about to begin flight testing and wanted the airplane to be perfect, I almost tried the "fix" myself. It seemed so radical and risky, however, that I decided to fly it first and see how it handled. Admittedly, there was one embarrassing moment with the first high-speed taxi test but that was completely attributable to the pilot. 



steve eccles <eccles(at)Chartermi.net> wrote:

  [quote]--> Kitfox-List message posted by: "steve eccles"  



everyone ,

I'm not wanting to argue about the toe in or out I'm just stating what

worked for me. since you are all the manufactures you can do whatever you

want and that is the GREAT part of building your own aircraft. the Kitfox

is a very well designd aircraft and fits the homebuilder very well

Steve



--

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