taildragger toe-in vs toe-out AGAIN

[Joa]

OK, I've researched this a fair bit and am still hearing two definite
different views. One one hand you have those that swear you need
toe-out and then on the other you have (among others- these are the
few I'm certain about) Cessna 100 series, Huskies, and Pitt's that all
are set with slight toe-in by the factory. Granted these are set
without weight on the aircraft and the toe-in may change slightly when
under load.

I think it boils down to what wins when you start to go into a turn
with a taildragger- does the toed-in outside wheel "drag" and thus
want to straighten you back out or does the toed-out outside wheel get
weight transferred to it and tend to straighten you out (vs tightening
the turn)?

Anybody with some definite answers based on physics? There's lots of
emperical and experiential opinions out there, anybody with some more
factual answers to the argument?

J oa

[Drew Dalgleish]

On 14 Nov 2003 10:07:59 -0800, (Joa) wrote:

>OK, I've researched this a fair bit and am still hearing two definite
>different views. One one hand you have those that swear you need
>toe-out and then on the other you have (among others- these are the
>few I'm certain about) Cessna 100 series, Huskies, and Pitt's that all
>are set with slight toe-in by the factory. Granted these are set
>without weight on the aircraft and the toe-in may change slightly when
>under load.
>
>I think it boils down to what wins when you start to go into a turn
>with a taildragger- does the toed-in outside wheel "drag" and thus
>want to straighten you back out or does the toed-out outside wheel get
>weight transferred to it and tend to straighten you out (vs tightening
>the turn)?
>
>Anybody with some definite answers based on physics? There's lots of
>emperical and experiential opinions out there, anybody with some more
>factual answers to the argument?
>
>J oa

What's wrong with putting the wheels on straight?

[Lpmcatee356]

>What's wrong with putting the wheels on straight?
>

Or not even fixed - like crosswind gear?

Seems to me that there might be a few parameters to many to make a "scientific"
generalization. This may be an area where it's best to just go with the
conventional wisdom, hope it works, and if it doesn't, do a bit of
experimenting.

The conventional wisdom does not work with my brand of 'dragger, but then it's
kind of odd. Q

[JFLEISC]

>There's lots of
>emperical and experiential opinions out there, anybody with some more
>factual answers to the argument?

I've pondered this thing myself. Problem with tail draggers (actually a
characteristic of aircraft and their need to have flexible gear way out on
spindly aerodynamic legs) is that toe out could change to toe in depending on
the load. This also changes during the transition from ground to flight. Worse
yet (the big problem with my plane) is the toe change as I bring the tail up on
take off or transition down during landing. Suffice to unscientificlly say that
20 years in the automotive alignment business has shown me that cars with toe
out tend to be a bit more twitchy than those with toe in. Have no idea if that
translates to aircraft because taildragger pilots EXPECT the plane to try to
swap ends.

Jim

[Ed Wischmeyer]

> Suffice to unscientificlly say that
> 20 years in the automotive alignment business has shown me that cars with toe
> out tend to be a bit more twitchy than those with toe in. Have no idea if that
> translates to aircraft

It does not. You want a small amount of toe out with the weight on the
wheels. Do a deja search and find some good posts on the topic.

One of the key points has to do with which way the wheels point when one
wing is up.

Ed Wischmeyer

[- Barnyard BOb -]

On 15 Nov 2003 00:22:09 GMT, (JFLEISC) wrote:

>>There's lots of
>>emperical and experiential opinions out there, anybody with some more
>>factual answers to the argument?
>
>I've pondered this thing myself. Problem with tail draggers (actually a
>characteristic of aircraft and their need to have flexible gear way out on
>spindly aerodynamic legs) is that toe out could change to toe in depending on
>the load. This also changes during the transition from ground to flight. Worse
>yet (the big problem with my plane) is the toe change as I bring the tail up on
>take off or transition down during landing. Suffice to unscientificlly say that
>20 years in the automotive alignment business has shown me that cars with toe
>out tend to be a bit more twitchy than those with toe in. Have no idea if that
>translates to aircraft because taildragger pilots EXPECT the plane to try to
>swap ends.
>
>Jim
+++++++++++++++++++++++

TOE IN is a NO-NO for tail draggers.
Just the reverse of cars.

Read the archives.
This has been beaten to death.
Many times.


Barnyard BOb -

[clare @ snyder.on .ca]

On Fri, 14 Nov 2003 19:12:31 -0600, - Barnyard BOb - >
wrote:

>On 15 Nov 2003 00:22:09 GMT, (JFLEISC) wrote:
>
>>>There's lots of
>>>emperical and experiential opinions out there, anybody with some more
>>>factual answers to the argument?
>>
>>I've pondered this thing myself. Problem with tail draggers (actually a
>>characteristic of aircraft and their need to have flexible gear way out on
>>spindly aerodynamic legs) is that toe out could change to toe in depending on
>>the load. This also changes during the transition from ground to flight. Worse
>>yet (the big problem with my plane) is the toe change as I bring the tail up on
>>take off or transition down during landing. Suffice to unscientificlly say that
>>20 years in the automotive alignment business has shown me that cars with toe
>>out tend to be a bit more twitchy than those with toe in. Have no idea if that
>>translates to aircraft because taildragger pilots EXPECT the plane to try to
>>swap ends.
>>
>>Jim
>+++++++++++++++++++++++
>
>TOE IN is a NO-NO for tail draggers.
>Just the reverse of cars.
>
And many cars actually DO have a toe out spec.
The ideal is for the wheels to roll 100% straight down the road.
Depending on steering geometry, they will try to toe out, or in. The
spec is to set them toed in if they tend to toe out, and out if they
tend to toe in, so that the natural forces pull the wheels towards the
straight ahead position. GENERALLY, vehicles with front wheel drive
tend to have toe out specs. ( Austin mini (old) was 0.062 inch toe
out) - but more and more you are seeing spec of 0 +/-.
The position of the tie rod, either ahead of or behind the steering
axis had some effect, as does the position of the intersection between
the KPI and the wheel centerline (camber).

Positive camber contributes to a toe-out tendancy ( that's why cars
tend to pull to the side with the most positive camber) (also think
about the handling of a bicycle)and Negative caster has the same
tendancy.
On an aircraft landing gear, the camber is self evident - and the
"effective" camber changes with load, and is effected by "unballanced"
landings (one wheel first). If the landing gear has "caster" it
changes between tail-up and tail-down attitudes. The different
combinations of uneven loading and landing attitudes will all effect
the "toe" behaviour of the wheel - so it is dangerous to make a
statement that either toe out or toe in is NECESSARILY more desirable
on a particular plane.


>Read the archives.
>This has been beaten to death.
>Many times.
>
>
>Barnyard BOb -
>
>
>

[Del Rawlins]

On 14 Nov 2003 04:12 PM, - Barnyard BOb - posted the following:

> TOE IN is a NO-NO for tail draggers.
> Just the reverse of cars.

One of the instructors at the local A&P school tried to convince me
otherwise, unsuccessfully, I might add.

----------------------------------------------------
Del Rawlins-
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

[Ryan Young]

(Joa) wrote in message >...
> OK, I've researched this a fair bit and am still hearing two definite
> different views. One one hand you have those that swear you need
> toe-out and then on the other you have (among others- these are the
> few I'm certain about) Cessna 100 series, Huskies, and Pitt's that all
> are set with slight toe-in by the factory. Granted these are set
> without weight on the aircraft and the toe-in may change slightly when
> under load.

I just pulled out my copy of Ladislao Pazmanys "Landing Gear Design
For Light Aircraft, Volume I", and he comes to no conclusion either.
>
> I think it boils down to what wins when you start to go into a turn
> with a taildragger- does the toed-in outside wheel "drag" and thus
> want to straighten you back out or does the toed-out outside wheel get
> weight transferred to it and tend to straighten you out (vs tightening
> the turn)?

My take on the physics is that the inertial forces generated in even
an incipient groundloop are WAY bigger than the restoring forces that
either of these possible mechanisms could generate.
>
> Anybody with some definite answers based on physics? There's lots of
> emperical and experiential opinions out there, anybody with some more
> factual answers to the argument?

Not that I'm aware of.

Chapter 3 of this reference does go into the forces and couples
involved in a ground loop, in a qualatative way. Simply put, the
gross geometry of the airplane seems to have more to do with it than
the fine geometery of the wheel alignment.

[Stealth Pilot]

On 14 Nov 2003 10:07:59 -0800, (Joa) wrote:

>OK, I've researched this a fair bit and am still hearing two definite
>different views. One one hand you have those that swear you need
>toe-out and then on the other you have (among others- these are the
>few I'm certain about) Cessna 100 series, Huskies, and Pitt's that all
>are set with slight toe-in by the factory. Granted these are set
>without weight on the aircraft and the toe-in may change slightly when
>under load.
>
>I think it boils down to what wins when you start to go into a turn
>with a taildragger- does the toed-in outside wheel "drag" and thus
>want to straighten you back out or does the toed-out outside wheel get
>weight transferred to it and tend to straighten you out (vs tightening
>the turn)?
>
>Anybody with some definite answers based on physics? There's lots of
>emperical and experiential opinions out there, anybody with some more
>factual answers to the argument?
>
>J oa

this has been done to death with adherents in both camps who may not
have ever flown taildraggers.

I fly a Wittman W8 Tailwind. (about 220 hours now)

my experience is that the geometry of the undercart does not correct
for groundloop tendency. it's influences in the forces at play are
fairly minor, HOWEVER having slight toe out is buckets better than
slight toe in because in the swerve of an impending groundloop the
inertia of the aircraft will lift all the weight off of the inboard
wheel (so it doesnt matter where it points really) and will place all
the weight on the outboard (outer edge of the turn) wheel. in this
condition slight toe out will have the wheel pointing in the direction
of forward travel and so it will not be working against your efforts
with rudder to straighten out the aircraft. toe in would provide just
that little bit more of a tendency to groundloop that you need to
overcome with rudder force.

now the order of toe out on my tailwind is not extreme.
in tail up takeoff position with the full aircraft weight on the
axles, ( the aircraft sitting with the bare axles on pine boards and
the fuselage level, ie without the 5.00x5 wheels on) the axles are
slightly lower at the outer end than the inner (about 5mm) and are
slightly more aft at the outer end than the inner end (again about
5mm).

while that setup works ok with the tailwind and it's taper spring legs
you might want to look closely at other aircraft with similar gear
geometries to what you are interested in before deciding.
I've been told that the RV6 has interesting gear behaviour under
deflection which is different from the tailwind.
Stealth Pilot

[Stealth Pilot]

I should add that in the considerations regarding handling of a
taildragger tyre pressure and tailwheel alignment and gearing are
quite critical as well.

25psi on my tailwind has as much bearing as anything regarding
handling. below 25psi and it is directionally interesting, much above
25psi and it is a bugger to land but very easy to bounce, and bounce,
and bounce.

having the neutral point of the rudder and tailwheel together is
critical. if they are offset from each other you get this very
squirrelly roll out as one has effect, then the other, then the other
until you finally run out of rudder.

the gearing of the tailwheel is important to relaxed landing as well.
having the tailwheel overgeared makes the landing a nightmare.
I tamed mine by moving the link arm in to about half the prior
distance where it attaches to the rudder.


these are all items just as important as toe in/out when considering
taildragger gear.

Stealth Pilot

btw how anyone lands a taildragger with sloppy spring links to the
tailwheel is beyond me.

[Stealth Pilot]

On 14 Nov 2003 10:07:59 -0800, (Joa) wrote:

to directly answer your questions...

> Granted these are set
>without weight on the aircraft and the toe-in may change slightly when
>under load.

that is a very important issue. what the legs are set at without load
is irrelevant. it is the position of the wheel under load that is of
critical importance. tapered spring legs will behave differently to
pivoting arms which will be different from linear compression legs
with scissor guides. (tailwind vs Auster vs jodel)
>
>I think it boils down to what wins when you start to go into a turn
>with a taildragger- does the toed-in outside wheel "drag" and thus
>want to straighten you back out or does the toed-out outside wheel get
>weight transferred to it and tend to straighten you out (vs tightening
>the turn)?
>
see my other post but I will make the comment that the way a toed in
wheel behaves is entirely dependent on the surface itr is rolling on.
it is likely to be manageable on grass because of the unherent sliding
that makes grass so much of a pleasure to land on.
a wheel with toe in on bitumen would be a decided handful because it
would track in the direction that it was pointed. there is very little
slippage experienced on bitumen which makes the requirements for
alignment before touchdown just that much more critical.

the key to avoiding groundloops is to land straight. dont let them set
up in the first place.

in heavy crosswinds I not averse to landing on the into wind wheel and
tailwheel and holding the wing down. I dont know what that does to the
geometry.

>Anybody with some definite answers based on physics?

what I've written is demonstrated physics with my aircraft.

> There's lots of
>emperical and experiential opinions out there, anybody with some more
>factual answers to the argument?
>
when you start out flying a taildragger dont underestimate the
difficulty, but dont over estimate it either.
learn to fly in ideal conditions. then as experience builds venture
gradually into less ideal conditions. you'll probably scare yourself a
few times and that is healthy. if you persist and master it you'll be
able to handle windsock horizontal conditions with confidence (you may
not enjoy them but you will be capable).

the opportunities for error until you master taildraggers are
considerable.
get yourself an experienced instructor to guide you through the first
few hours and you will be set for life.

be chastened by the example of the astronaut doctor who died in a
Tailwind. press on the wrong foot while correcting and it can be all
over in an instant.

Stealth Pilot

[Ed Wischmeyer]

> btw how anyone lands a taildragger with sloppy spring links to the
> tailwheel is beyond me.

On my RV-4, before we found that it had excessive toe out (almost 5/16"
across each axle vs a spec of 0 to .050"), I tried a number of tailwheel
springs and chain tensions. My hypothesis is that the sloppy spring
links let you get a bunch of rudder deflection before you get much
tailwheel deflection, and this is good at, say, 40MPH and above. Haven't
ever read anything about this, though.

Ed Wischmeyer

[- Barnyard BOb -]

e.net> wrote:

>> btw how anyone lands a taildragger with sloppy spring links to the
>> tailwheel is beyond me.
>
>My hypothesis is that the sloppy spring
>links let you get a bunch of rudder deflection before you get much
>tailwheel deflection, and this is good at, say, 40MPH and above. Haven't
>ever read anything about this, though.
>
>Ed Wischmeyer
+++++++++++++++++++++++++++++++++

Same experience here over the years, Ed.


Barnyard BOb --

[Dave Hyde]

Ed Wischmeyer wrote:

> My hypothesis is that the sloppy spring links let you get a bunch of
> rudder deflection before you get much tailwheel deflection, and this
> is good at, say, 40MPH and above.

This is interesting. One of the things my inspector asked
me to fix was the slop in the tailwheel springs. I got
almost all of it out, and the airplane handles very well
on the ground, but I haven't had it up to 40 mph yet. I've
flown two RV's with loose springs and I thought mine handled
better at low speed, but that may just be wishful thinking.
I've seen lots of recommendations from RV people to make sure
there's at least a little slack in the springs, and I don't
recall ever seeing any RV-flyer recommend NO slack.

My head hurts :-)

Dave 'still ground-bound' Hyde

[- Barnyard BOb -]

On Sat, 15 Nov 2003 17:56:40 GMT, Dave Hyde > wrote:

>> My hypothesis is that the sloppy spring links let you get a bunch of
>> rudder deflection before you get much tailwheel deflection, and this
>> is good at, say, 40MPH and above.
>
>This is interesting. One of the things my inspector asked
>me to fix was the slop in the tailwheel springs. I got
>almost all of it out, and the airplane handles very well
>on the ground, but I haven't had it up to 40 mph yet. I've
>flown two RV's with loose springs and I thought mine handled
>better at low speed, but that may just be wishful thinking.
>I've seen lots of recommendations from RV people to make sure
>there's at least a little slack in the springs, and I don't
>recall ever seeing any RV-flyer recommend NO slack.
>
>My head hurts :-)
>
>Dave 'still ground-bound' Hyde
++++++++++++++++++++++++++++

Your setup is fine...
for NO wind or wind STRAIGHT down the runway.

In a crosswind with CONTROLS CROSSED and
you're about to 3 point... guess what you got?

Yep... a rudder AND a tailwheel aimed towards
the boondocks. The stronger the crosswind,
the more problematic this can become.
depending on a lot of factors....
including one's experience level.

The following is my GENERAL statement:

YMMV.

For the most pleasant transition....
The aircraft needs springs that can yield
sufficiently in a timely manner, some 'slack'
to ameliorate this golly-woppled condition
or a combination of both. A lot of the setup
depends on pilot preferences.

Can one do without the above suggestions?
Sure. Beat your head against the wall, too.
That's my 2 cents - given many, many tailwheel
years and hours and I'm sticking to it. <g>

P.S.
Let me add... it's as much 'art' as science.


Barnyard BOb - no advocate of wheel landings

[Jerry Springer]

- Barnyard BOb - wrote:
> On Sat, 15 Nov 2003 17:56:40 GMT, Dave Hyde > wrote:
>
>
>>>My hypothesis is that the sloppy spring links let you get a bunch of
>>>rudder deflection before you get much tailwheel deflection, and this
>>>is good at, say, 40MPH and above.
>>
>>This is interesting. One of the things my inspector asked
>>me to fix was the slop in the tailwheel springs. I got
>>almost all of it out, and the airplane handles very well
>>on the ground, but I haven't had it up to 40 mph yet. I've
>>flown two RV's with loose springs and I thought mine handled
>>better at low speed, but that may just be wishful thinking.
>>I've seen lots of recommendations from RV people to make sure
>>there's at least a little slack in the springs, and I don't
>>recall ever seeing any RV-flyer recommend NO slack.
>>
>>My head hurts :-)
>>
>>Dave 'still ground-bound' Hyde
>
> ++++++++++++++++++++++++++++
>
> Your setup is fine...
> for NO wind or wind STRAIGHT down the runway.
>
> In a crosswind with CONTROLS CROSSED and
> you're about to 3 point... guess what you got?
>
> Yep... a rudder AND a tailwheel aimed towards
> the boondocks. The stronger the crosswind,
> the more problematic this can become.
> depending on a lot of factors....
> including one's experience level.
>
> The following is my GENERAL statement:
>
> YMMV.
>
> For the most pleasant transition....
> The aircraft needs springs that can yield
> sufficiently in a timely manner, some 'slack'
> to ameliorate this golly-woppled condition
> or a combination of both. A lot of the setup
> depends on pilot preferences.
>
> Can one do without the above suggestions?
> Sure. Beat your head against the wall, too.
> That's my 2 cents - given many, many tailwheel
> years and hours and I'm sticking to it. <g>
>
> P.S.
> Let me add... it's as much 'art' as science.
>
>
> Barnyard BOb - no advocate of wheel landings

I agree with both Dave and Bob I have put many hours on my RV-6 in both
configurations. With tight tailwheel springs it is much easier to handle taxing
and takeoffs and landings in a NO WIND condition. But now add some cross wind
and things can get "golly-woppled"** in a hurry with tight springs. Bob is
correct when he says you need SOME slack. Another consideration for spring
tension is whether you can get full rudder deflection in both directions with
tight springs.
My preference at least on an RV-6 is some slack in the springs, which IMO is a
better compromise for all taxi, takeoff, landing configurations.

**Bob's words :-)

Jerry

[Ron Wanttaja]

On Sat, 15 Nov 2003 20:39:29 GMT, Jerry Springer >
wrote:

>Another consideration for spring
>tension is whether you can get full rudder deflection in both directions with
>tight springs.

And yet ANOTHER consideration (depending upon aircraft type) is whether the
tailwheel-mounting spring relaxes when the tailwheel is off the ground.
That may increase the distance between your rudder horn and your tailwheel
horn, not a good situation if your link between the two is tight on the
ground.

Ron Wanttaja

[Model Flyer]

"- Barnyard BOb -" > wrote in message

> >translates to aircraft because taildragger pilots EXPECT the plane
to try to
> >swap ends.
> >
> >Jim
> +++++++++++++++++++++++
>
> TOE IN is a NO-NO for tail draggers.
> Just the reverse of cars.
>

It depends on whether you have a front or rear wheel drive car,
toe-out for front wheel drive and toe-in for rear wheel drive,
generally speaking anyway. Just because I can't think of a car with
something quite different doesn't mean that it isn't the case, just
that I can't think of it.:-))
--
---
Cheers,
Jonathan Lowe.
/
don't bother me with insignificiant nonsence such as spelling,
I don't care if it spelt properly
/
Sometimes I fly and sometimes I just dream about it.
:-)


> Read the archives.
> This has been beaten to death.
> Many times.
>
>
> Barnyard BOb -
>
>
>
>

[Dave Hyde]

Jerry Springer wrote:

> With tight tailwheel springs it is much easier to handle taxing
> and takeoffs and landings in a NO WIND condition. But now add some cross wind
> and things can get "golly-woppled"** in a hurry with tight springs.

Thanks, BOb and Jerry. Good thing I've got some extra chain
laying around. All I need now is 10 extra hours in a day.

Dave 'anti-wopple chain' Hyde

[Stealth Pilot]

On Sat, 15 Nov 2003 20:49:41 GMT, Ron Wanttaja >
wrote:

>On Sat, 15 Nov 2003 20:39:29 GMT, Jerry Springer >
>wrote:
>
>>Another consideration for spring
>>tension is whether you can get full rudder deflection in both directions with
>>tight springs.
>
>And yet ANOTHER consideration (depending upon aircraft type) is whether the
>tailwheel-mounting spring relaxes when the tailwheel is off the ground.
>That may increase the distance between your rudder horn and your tailwheel
>horn, not a good situation if your link between the two is tight on the
>ground.
>
>Ron Wanttaja

these experiences are interesting. I guess you sort it out by having a
fly of typical aircraft to see whether the results match your flying
style.

on my Tailwind the link rod and taper spring are pretty well together
and parallel when you look at them in elevation.
bouncing the tail up and down doesnt produce any noticeable movement
of the tailwheel.

tailwheels are like yellow volkswagens. you only start noticing them
when you have one at the top of your mental focus. after I sorted out
my tailwheel I started noticing them in photos. Pitts Specials quite
often have the same setup, and in articles in Sport Aviation I notice
that the setup is preferred by others with short coupled frisky
aircraft.

A friend building a Sonerai did some comparisons with all the
homebuilts on our airfield (probably 50 or so) and showed me his wing
tip rock test. you hold the wing tip and rock it up and down while
watching the tailwheel. his target was a tailwheel which didnt move
because of the rocking. of all the aircraft he looked at he said that
mine was the most rigid of the setups and the only one that didnt
wobble all over the place. oddly it is one of the lighest. it is a bog
standard Wittman tapered spring tailwheel setup in tempered SAE4140
steel. works well (though I'm not starting a religion over it :-) )

I hope the guy who posed the original question got something useful
from all of this. I thought he deserved a decent reply.
Stealth Pilot
Australia.

[Ed Wischmeyer]

> All I need now is 10 extra hours in a day.

Quit wasting time on this newsgroup!! :-)

Ed "not practicing what I preach" Wischmeyer

[w b evans]

I think all this toein/toeout stuff comes into play before the tailwheel is
even down.--
walt evans
NX140DL

"Stealth Pilot" > wrote in message
...
> I should add that in the considerations regarding handling of a
> taildragger tyre pressure and tailwheel alignment and gearing are
> quite critical as well.
>
> 25psi on my tailwind has as much bearing as anything regarding
> handling. below 25psi and it is directionally interesting, much above
> 25psi and it is a bugger to land but very easy to bounce, and bounce,
> and bounce.
>
> having the neutral point of the rudder and tailwheel together is
> critical. if they are offset from each other you get this very
> squirrelly roll out as one has effect, then the other, then the other
> until you finally run out of rudder.
>
> the gearing of the tailwheel is important to relaxed landing as well.
> having the tailwheel overgeared makes the landing a nightmare.
> I tamed mine by moving the link arm in to about half the prior
> distance where it attaches to the rudder.
>
>
> these are all items just as important as toe in/out when considering
> taildragger gear.
>
> Stealth Pilot
>
> btw how anyone lands a taildragger with sloppy spring links to the
> tailwheel is beyond me.

[JFLEISC]

>It depends on whether you have a front or rear wheel drive car,
>toe-out for front wheel drive and toe-in for rear wheel drive,
>generally speaking anyway. Just because I can't think of a car with
>something quite different doesn't mean that it isn't the case, just
>that I can't think of it.:-))

OK, just to add more fuel to the fire. As I said I had 20 years of doing car
alignments with repete customers so I got many chances to see "long term"
results. If a car "needs" some sort of "preset" (toe in or toe out) to
compensate for what will happen when it is driven then experience has tought me
that something is generally loose that needs fixing first. Customers want two
things; First they want the car to go down the road straight when they take
their hands off the wheel. (don't ask me why the hell they are taking their
hands off the wheel, I couldn't figure that one out). They also want their
tires to wear evenly. End of story. Tried many manufacturer's recommendations
over the years but zero toe in always proved the best to keep them happy and
coming back.
The inner side of the right tire always seems to wear more on my RV. Don't know
why and don't care. Rotating them and flipping them on the wheels each odd year
gets me 200 hours out of a set. Can't complain; cheap tires and it's the most
stable tail dragger I've ever landed. (my tail wheel springs are snug and the
wheel is the old non-pivoting type. couldn't tell you if that's good or bad)

Jim

[Corky Scott]

On 18 Nov 2003 00:51:52 GMT, (JFLEISC) wrote:

Customers want two
>things; First they want the car to go down the road straight when they take
>their hands off the wheel. (don't ask me why the hell they are taking their
>hands off the wheel, I couldn't figure that one out).
>Jim

It's not that they want to drive with their hands off the steering
wheel Jim, it's that they don't want the car pulling to one side or
the other. I don't like that either. When I find that happening to
my car it drives me to distraction. I don't want to have to hold
constant pressure on the steering wheel to make sure the car is
tracking straight down the road (unless the road is crowned, or there
is a steady side wind).

I used to do alignments too. I remember one guy who came in with a
Datsun 2000Z and was complaining about it pulling to one side. Z
cars, like many Japanese cars and a lot of cars now, don't have any
adjustments for castor or camber. All I could do was adjust toe-in,
and that would not correct for a pulling condition. So I took the car
out on the road to find out if it really was pulling. The wind was
blowing strongly directly out of the west that day and the interstate
heads north and south. The car veered to the left when heading south,
and veered to the right when heading north. It COULD NOT be a
mechanical pulling problem or the car would have veered only one way.

I explained that the high winds were simply blowing his car to one
side. He didn't believe me. I suggested we go for a test drive. He
drove. We went south on the interstate, I told him to let go of the
wheel. Sure enough, it veered left. I pointed out the bending
treetops, which were showing us which way the wind was blowing. We
turned around and headed north. Same thing, let go of the wheel and
the car now veered to the right.

I explained that there was no adjustment I could make to correct for a
pulling condition, that the wind was causing his problem that day.

I still did not believe me. Drove away convinced I was just trying to
avoid doing a good alignment.

Corky Scott

[Stealth Pilot]

On Mon, 17 Nov 2003 17:37:52 -0500, "w b evans" >
wrote:

>I think all this toein/toeout stuff comes into play before the tailwheel is
>even down.--
>walt evans
>NX140DL
>
comes into play at any time you get the aircraft off line and are
recovering to straight. regardless of where the tailwheel is.
if you keep it dead straight it is all insignificant.
Stealth Pilot

[JFLEISC]

>it's that they don't want the car pulling to one side or
>the other.

Ya think?

[Martin Morgan]

Ed Wischmeyer wrote:
>>Suffice to unscientificlly say that
>>20 years in the automotive alignment business has shown me that cars with toe
>>out tend to be a bit more twitchy than those with toe in. Have no idea if that
>>translates to aircraft
>
>
> It does not. You want a small amount of toe out with the weight on the
> wheels. Do a deja search and find some good posts on the topic.
>
> One of the key points has to do with which way the wheels point when one
> wing is up.
>
> Ed Wischmeyer

Having had 2 A/C that were a nightmare on the ground until changing the
geometry I wholeheartedly agree.

Note the the aforementioned "wing up" condition can be from a crosswind
landing (take off), you are coming down from a bounce or a bunch of others.

There have been a bunch of comments about other factors, and they make
sense. However in my case I had a Rans Chaos and a Pitts S1-S that were
both more than a handful. Both had toe in. The previous owner of the
Pitts had never been seen to do a good landing but was an excellent
pilot. After setting them up with 0.5 deg of toe out (3 point attitude
with flying weight, set up on greased plates for acuracy) they were both
fabulous to land. Note that I made no other change in either case.

My Pitts only deviates (on the runway..) with the first input of power
on takeoff or if I push on a pedal.

Darrol Stinton in "The Design of the Aeroplane" (excellent book) clearly
states that taildraggers should be set up at 0 deg or some toe out.
NEVER toe in.

A previous comment mentioned that the Pitts factory set their a/c up
with toe in. Given than all Pitts a/c have an evil repution on the
ground (and that mine is now excellent with this one change) do you
think that this is good thing?

Regards

Martin Morgan

[- Barnyard BOb -]

On Mon, 24 Nov 2003 12:22:05 +1100, Martin Morgan
> wrote:


>Darrol Stinton in "The Design of the Aeroplane" (excellent book) clearly
>states that taildraggers should be set up at 0 deg or some toe out.
>NEVER toe in.
>
>A previous comment mentioned that the Pitts factory set their a/c up
>with toe in. Given than all Pitts a/c have an evil repution on the
>ground (and that mine is now excellent with this one change) do you
>think that this is good thing?
>
>Regards
>
>Martin Morgan
++++++++++++++++++++++++++++++++++++++

Plain or plane truth....

No matter how much testimony is given from those
of us with multiple decades and thousands of hours
of success, there remains that ever present vocal
minority which only finds solace in opposition. They
can be convinced of nothing. For these tortured
souls, the wheel MUST be reinvented and history
MUST be repeated.... usually by somebody else
that they will never believe, either.

Barnyard BOb -- over 50 years of successful flight

[Andrew Rowley]

- Barnyard BOb - > wrote:

>On Mon, 24 Nov 2003 12:22:05 +1100, Martin Morgan
> wrote:
>
>
>>Darrol Stinton in "The Design of the Aeroplane" (excellent book) clearly
>>states that taildraggers should be set up at 0 deg or some toe out.
>>NEVER toe in.
>>
>>A previous comment mentioned that the Pitts factory set their a/c up
>>with toe in. Given than all Pitts a/c have an evil repution on the
>>ground (and that mine is now excellent with this one change) do you
>>think that this is good thing?
>>
>>Regards
>>
>>Martin Morgan
>++++++++++++++++++++++++++++++++++++++
>
>Plain or plane truth....
>
>No matter how much testimony is given from those
>of us with multiple decades and thousands of hours
>of success, there remains that ever present vocal
>minority which only finds solace in opposition. They
>can be convinced of nothing. For these tortured
>souls, the wheel MUST be reinvented and history
>MUST be repeated.... usually by somebody else
>that they will never believe, either.

Who are you accusing of reinventing the wheel? The Pitts factory, or
the person who improved the landings by removing the toe in?

[- Barnyard BOb -]

Andrew Rowley > wrote:

>>>Darrol Stinton in "The Design of the Aeroplane" (excellent book) clearly
>>>states that taildraggers should be set up at 0 deg or some toe out.
>>>NEVER toe in.
>>>
>>>A previous comment mentioned that the Pitts factory set their a/c up
>>>with toe in. Given than all Pitts a/c have an evil repution on the
>>>ground (and that mine is now excellent with this one change) do you
>>>think that this is good thing?
>>>
>>>Regards
>>>
>>>Martin Morgan
>>++++++++++++++++++++++++++++++++++++++
>>
>>Plain or plane truth....
>>
>>No matter how much testimony is given from those
>>of us with multiple decades and thousands of hours
>>of success, there remains that ever present vocal
>>minority which only finds solace in opposition. They
>>can be convinced of nothing. For these tortured
>>souls, the wheel MUST be reinvented and history
>>MUST be repeated.... usually by somebody else
>>that they will never believe, either.
>
>Who are you accusing of reinventing the wheel? The Pitts factory, or
>the person who improved the landings by removing the toe in?
+++++++++++++++++++++++++++++++++

Sorry for not being clear to all, but...
The RAH vocal minority does *NOT* include:

Darrol Stinton
Pitts factory
Martin Morgan

FWIW..
I've no idea what the Pitt's uses,
but my RV-3 is short coupled
and tracks straight as an arrow...
with a tad of TOE OUT.

My Fly Baby of the '60's had ZERO...
and was a ground handling dream.

FWIW--
Most of my 50 years of successful flight is in taildraggers.
With no ground loop experience, I am no expert, so...

Who here has a ton of ground looping in their log book?
The details of your experiences are welcome here as
fodder for the 'great toe in - toe out debate'. :o)


Barnyard BOb - senior member of the NO TOE IN CLUB

[Marvin Barnard]

On my recent homebuilt I started with 5/16" toe out. I did find one
improvement with decreasing the amount of toe out back to zero. Steering
is more responsive. Landing seems to be about the same. (No violent
nature)

[Mr Nobody]

On Fri, 14 Nov 2003 10:07:59 -0800, Joa wrote:

> OK, I've researched this a fair bit and am still hearing two definite
> different views. One one hand you have those that swear you need
> toe-out and then on the other you have (among others- these are the
> few I'm certain about) Cessna 100 series, Huskies, and Pitt's that all
> are set with slight toe-in by the factory. Granted these are set
> without weight on the aircraft and the toe-in may change slightly when
> under load.
>
> I think it boils down to what wins when you start to go into a turn
> with a taildragger- does the toed-in outside wheel "drag" and thus
> want to straighten you back out or does the toed-out outside wheel get
> weight transferred to it and tend to straighten you out (vs tightening
> the turn)?
>
> Anybody with some definite answers based on physics? There's lots of
> emperical and experiential opinions out there, anybody with some more
> factual answers to the argument?
>
> J oa

Toe in vs Toe out depends on the type of gear you have your wheels
connected to. This is the absolute first thing to consider before even
thinking about setting toe. If your gear is articulated you
need neutral or toe-in. Why? Because the gear legs will be forced apart
with toe out and the plane will start to sink on its gear. And it will
happen as you push it out of the hanger. It takes very little to get the
gear legs to spread if there is toe out. The rate at which it will sink
depends on the amount of toe out. So if you have bungees or
springs on some sort of A arm gear legs please don't use any toe-out.


If you have fixed gear like a one piece steel or aluminum unit then you
can consider all these other posts about how it should be set.

Mike

[clare @ snyder.on .ca]

On Fri, 28 Nov 2003 17:21:21 GMT, Mr Nobody >
wrote:

>> J oa
>
>Toe in vs Toe out depends on the type of gear you have your wheels
>connected to. This is the absolute first thing to consider before even
>thinking about setting toe. If your gear is articulated you
>need neutral or toe-in. Why? Because the gear legs will be forced apart
>with toe out and the plane will start to sink on its gear. And it will
>happen as you push it out of the hanger. It takes very little to get the
>gear legs to spread if there is toe out. The rate at which it will sink
>depends on the amount of toe out. So if you have bungees or
>springs on some sort of A arm gear legs please don't use any toe-out.
>
>
I'll take issue here.
Your plane is so light the wheels will "scuff" long before they squat
the suspension enough to affect anything. Particularly when talking
only a few degrees of toe-out.
Now, if you were putting thousands of miles on the plane on the ground
tire wear would possibly become an issue, but you FLY the thing.
>If you have fixed gear like a one piece steel or aluminum unit then you
>can consider all these other posts about how it should be set.
>
>Mike

[JFLEISC]

One other thing to consider (and I can't help but wonder if it makes a greater
difference than initial toe in or out setting) is the angle (camber) of the
tire as it sits on the ground. The camber obviously changes with the weight on
the gear at any time. The problem is the bias ply tires that are on light
aircraft. They normally tend to want to steer toward the way they are leaning
as slight as that may be. Inflation could also effect this tendency.

Jim