aircraft designs prone to ground looping
Frank Stutzman
It got me to thinking about what design characteristics would make
a plane more or less prone to ground looping.
I assume a short coupled plane like a Pitts is much more prone than
something like a Cessna 180. What about main gear wheel base has an
affect (I doubt a dragonfly with the originally designed gear could be
ground looped :-)? What about rudder size/authority?
Thoughts?
Frank Stutzman
Bonanza N494B (no tail wheel here)
Hood River, OR
John J. Miller
<864ujv$4e5$1...@cartero.kjsl.com>:
>
>I assume a short coupled plane like a Pitts is much more prone than
>something like a Cessna 180. What about main gear wheel base has an
>affect (I doubt a dragonfly with the originally designed gear could be
>ground looped :-)? What about rudder size/authority?
>
>Thoughts?
>
View the plane from the top as an isosceles triangle with the main wheels
at the points of the short end with the CG point somewhere inside the
triangle. (If the CG point isn't inside the triangle the plane will fall
over.) The closer the CG point is to the axle and the center line of the
aircraft the less leverage is available for the CG to turn the plane to
cause a ground loop. The larger the rudder the greater the control
leverage available to the pilot to prevent a ground loop. And the wider
the wheelbase the more the CG point has to go to gain leverage against the
wheel base center to force the loop.
John J. Miller
jo...@mcdata.com
John Armbrust
--
John W. Armbrust
Frank Stutzman <stut...@stutzman.com> wrote in message
news:864ujv$4e5$1...@cartero.kjsl.com...
| There is a discussion of ground looping tail wheel aircraft in r.a.p.
| It got me to thinking about what design characteristics would make
| a plane more or less prone to ground looping.
|
| I assume a short coupled plane like a Pitts is much more prone than
| something like a Cessna 180. What about main gear wheel base has an
| affect (I doubt a dragonfly with the originally designed gear could be
| ground looped :-)? What about rudder size/authority?
|
| Thoughts?
|
J&D
zero or have a small amount of toe-OUT. With a taildragger, toe-in
aggravates the natural instability that is already there. Toe-out gives a
slight "crosswind gear" effect and tends to be stabilizing, the opposite
of the way it should be in a trike..
JKahn
Ed Sullivan
>There is a discussion of ground looping tail wheel aircraft in r.a.p.
>It got me to thinking about what design characteristics would make
>a plane more or less prone to ground looping.
>
>I assume a short coupled plane like a Pitts is much more prone than
>something like a Cessna 180. What about main gear wheel base has an
>affect (I doubt a dragonfly with the originally designed gear could be
>ground looped :-)? What about rudder size/authority?
>
>Thoughts?
>
>Frank Stutzman
>Bonanza N494B (no tail wheel here)
>Hood River, OR
I think you might find that the placement of the main gear in relation to the CG would have more effect than wheelbase.
Actually a Pitts is easier to recover from a loop than a 180. I can't speak for a dragonfly, but a Quickie will perform
a groundloop that will curl your hair. They don't care which end is forward. About the only thing that saves them is
they didn't have differential braking.
Ed Sullivan
Ed Sullivan
>Taildraggers with toe-in can be very squirrely. Taildraggers should be
>zero or have a small amount of toe-OUT. With a taildragger, toe-in
>aggravates the natural instability that is already there. Toe-out gives a
>slight "crosswind gear" effect and tends to be stabilizing, the opposite
>of the way it should be in a trike..
>
>JKahn
>
Also the tail wheel verticle shaft should be canted forward at the top a bit which tends to keep the tailwheel in trail.
Ed
luc...@metrowerks.com
Frank Stutzman <stut...@stutzman.com> wrote:
I had an R/C Skybolt (about 1/5 size) that was very prone to ground
looping. That thing spun around if you just looked at it funny - it was
heavy and its CG was well behind the main gear, which I think
contributed to that.
Come to think of it, I have years and years of tailwheel R/C experience
(before I switched to fling-wing for the last year I flew R/C), but no
full-scale tailwheel. Sure wish that experience carried over.....
Lucien S.
PP-ASEL.
Captain America IV.
> There is a discussion of ground looping tail wheel aircraft in r.a.p.
> It got me to thinking about what design characteristics would make
> a plane more or less prone to ground looping.
>
> I assume a short coupled plane like a Pitts is much more prone than
> something like a Cessna 180. What about main gear wheel base has an
> affect (I doubt a dragonfly with the originally designed gear could be
> ground looped :-)? What about rudder size/authority?
>
> Thoughts?
>
> Frank Stutzman
> Bonanza N494B (no tail wheel here)
> Hood River, OR
>
Sent via Deja.com http://www.deja.com/
Before you buy.
Mark Hickey
>Also the tail wheel verticle shaft should be canted forward at the top a bit which tends to keep the tailwheel in trail.
This might actually make it harder to get proper trail...
Trail is the difference between where the line from the pivot (the
"vertcal shaft") intersects the ground, and the contact point of the
tire. The more trail, the more "stable" the rear wheel will be.
Mark Hickey
Reid and Julie Baldwin
"J&D" <jk...@planeteer.com> wrote in message
news:38866758...@planeteer.com...
> Taildraggers with toe-in can be very squirrely. Taildraggers should be
> zero or have a small amount of toe-OUT. With a taildragger, toe-in
> aggravates the natural instability that is already there. Toe-out gives a
> slight "crosswind gear" effect and tends to be stabilizing, the opposite
> of the way it should be in a trike..
>
> JKahn
Any idea what the physics explanation of this is?
Assume that a plane with toe-in is disturbed slightly such that it is
pointing slightly
left of the direction it is moving. The left will will be better aligned
with the direction
of travel than the right wheel. I would think this would cause the right
wheel to
have more resistance than the left, creating a restoring moment. Therefore,
the toe-in
would help resist a ground-loop. Where does this logic go astray?
On a related note, a friend of mine is looking into buying a Maule and the
insurance
companies he has talked to tell him that Maules have a very bad
ground-looping
record. Any comment on what it is about a Maule that could lead to this? Is
this
more a reflection of what type of pilot flies a Maule or what type of
operation is
typical in a Maule than it is a reflection of the design?
Bruce A. Frank
Maule handles hardly better or worse than about a dozen other
conventional geared planes.
A tailwheel plane with toe-in:
As the plane steers from dead straight the wheel on the inside of the
turn looses some effective traction because it's more lightly loaded.
The wheel on the outside gains traction authority due to slight increase
in loading. It is toed-in so it steers towards the center exaggerating
the loss of traction of the other wheel and loading itself even more.
The wings are tipping towards the outside. The tailwheel is lightly
loaded so it exerts little forcr is correcting the turning. The rudder
cannot exert enough force to overcome the inertia of the event taking
place. As the plane rolls up on the outside wheel the tail begins to
swing to the outside of the turn, the plane tips till the outside wing
nearly (or does) touch the ground and the plane spins about its CG.
A tailwheel plane with toe-out:
As the plane steers from dead straight the wheel on the inside of the
turn looses some effective traction bacause it is more lightly loaded.
The wheel on the outside gains traction authority due to slight increase
in loading. It is toed-out so it steers away from the turn forcing the
weight of the plane back onto the other wheel allowing full control with
both wheels maintaining effective traction. The turn is less likely to
progress by itself so the slight missalignment is more easily corrected
with the minimally effective tailwheel and rudder.
This is oversimplification but contains the essentials.
--
Bruce A. Frank, Editor "Ford 3.8/4.2L Engine and V-6 STOL
BAFRANK(at)worldnet.att.net Homebuilt Aircraft Newsletter"
| Publishing interesting material|
| on all aspects of alternative |
| engines and homebuilt aircraft.|
*------------------------------**----*
\(-o-)/ AIRCRAFT PROJECTS CO.
\___/ Manufacturing parts & pieces
/ \ for homebuilt aircraft,
0 0 TIG welding
While trying to find the time to finish mine.
O-ring Seals
>In article <864ujv$4e5$1...@cartero.kjsl.com>,
> Frank Stutzman <stut...@stutzman.com> wrote:
>
>I had an R/C Skybolt (about 1/5 size) that was very prone to ground
>looping.
>
>Lucien S.
>PP-ASEL.
>Captain America IV.
>
Captain America,
I fail to see what model airplanes have to do with any of this.
I also think a better title for this thread would be 'PILOTS Subject
to Ground Looping'.
All of the designs out there have been flown successfully by many
pilots without ground looping them. Also, experienced tailwheel
pilots have ground looped airplanes of all types. If anyone is
looking at a design just to minimize their chances of embarrasing
themselves, thay should either get some more dual or stay away from
airplanes altogether. And that includes ones with nosewheels too.
Especially those with retractable landing gear.
O-ring Seals
Doug Hoffman
Why? Are the laws of physics, aerodynamics, etc. different for 25'
wingspans than for 10' wingspans (for example)?
The use of models can be a cheap and safe way to to study the
extremes of CG and so forth.
-Doug (who has flown both full scale and r/c models)
Frank Stutzman
> If anyone is
> looking at a design just to minimize their chances of embarrasing
> themselves, thay should either get some more dual or stay away from
> airplanes altogether. And that includes ones with nosewheels too.
> Especially those with retractable landing gear.
Actually, the reason behind my raising the qestion was was that I am
considering some modifications to an experimental design. My mods
would have an affect on the landing characteristics and I was wondering
if I would make those characteristics better or worse. From the
discussion so far, it sounds like I'm going to have to be much more
careful about my changes.
Frank Stutzman (needs much more tail wheel dual time, anbody volunteering?)
Bonanza N494B (already learned all the lessons about nose dragging retracts)
Hood River, OR
luc...@metrowerks.com
vint...@eudoramail.com (O-ring Seals) wrote:
> On Thu, 20 Jan 2000 19:41:10 GMT, luc...@metrowerks.com wrote:
>
> >In article <864ujv$4e5$1...@cartero.kjsl.com>,
> > Frank Stutzman <stut...@stutzman.com> wrote:
> >
> >I had an R/C Skybolt (about 1/5 size) that was very prone to ground
> >looping.
> >
> >Lucien S.
> >PP-ASEL.
> >Captain America IV.
> >
> Captain America,
That's my airplane's name; mine is Lucien.
> I fail to see what model airplanes have to do with any of this.
Same physical principles involved. Believe it.... Or not.....
Lucien S.
PP-ASEL.
Captain America IV.
k8...@pop3.concentric.net
out tending to bite the ground harder than the inside wheel, and bring the
foreward fuselage back around against the direction of the tail... Tough to
describe in words, easier to demonstrate with my hands (all pilots talk with
their hands, don't they?), but it does make a difference..
On Maules, and similar stance birds, they have to be flown every second they are
in motion... You can't drive them... In my day (groannnn - there he goes again!)
we all learned to fly in a conventional gear airplanes (you call them
taildraggers) so the general level of skill in ground handling them was markedly
higher than today, because every single take off and landing was done in a
taildragger right from the first hour with the instructor... We had continuous
training in them and experience counts... (I am not saying that we were better
overall pilots than today, just a whole bunch more experience with conventional
gear handling)
Today, with the tricycle gear being the "conventional" geared airplane, todays
pilots tend to relax the instant the wheels are on the ground because the plane
behaves more like a car and self corrects for being slightly off line, and less
like an airplane... Relax for a second in a Maule, or a T-Craft, or a Cub, etc.,
while rolling out and you will find out how it feels to ground loop...
A few years ago I sold a T-Craft to a fella who had a CFI rating but had never
flown conventional gear... Actually he had no problem with take off because the
rudder was effective as soon as the throttle went forward, and in the pattern he
flew the bird better than I ever had... But, the instant the wheels touched on
landing it became a Coney Island thrill ride... He never did learn to handle
the plane well in the three and a half hours of shooting landings I spent with
him... He just flew it away one morning and didn't come back... In his defense
I will note that he had about two dozen landings under his belt on conventional
gear and I had thousands... Experience counts...
Denny
George R. Patterson III
Reid and Julie Baldwin wrote:
>
> On a related note, a friend of mine is looking into buying a Maule and the
> insurance
> companies he has talked to tell him that Maules have a very bad
> ground-looping
> record. Any comment on what it is about a Maule that could lead to this? Is
> this
> more a reflection of what type of pilot flies a Maule or what type of
> operation is
> typical in a Maule than it is a reflection of the design?
It's a combination. The MX-7 series has fairly stiff gear, a big wing,
and a tail that looks like it was grafted off a Viking. It will bounce
easily, can float if improperly handled, and is sensitive to crosswinds.
It will weathervane at low speeds more easily than many others. The
landing technique recommended by the factory for use in crosswinds is to
come in with 0 or -7 degrees of flaps and three-point the aircraft. This
will require a bit of a sideslip and power - the power and high airspeed
gives the pilot good rudder authority.
Unfortunately, it's no longer a short landing airplane when you bring it
in like that. A pilot trying to get into a short field may carry more
flaps than adviseable, and the plane will start to swing just before or
after touchdown. There's also the situation that conventional wisdom
says that the "correct" way to handle crosswinds is to wheel land the
plane. Maule recommends against wheel landings for the MX-7, but I know
of one MX-7 owner who is adamant that "Ray Maule don't know what he's
talking about." Pilots with lots of experience in other taildraggers can
be the highest risk pilots in Maules.
George Patterson, N3162Q.
O-ring Seals
wrote:
>In article <3887a268....@news.psnw.com> O-ring Seals,
>vint...@eudoramail.com writes:
>>I fail to see what model airplanes have to do with any of this.
>>
>
>Why? Are the laws of physics, aerodynamics, etc. different for 25'
>wingspans than for 10' wingspans (for example)?
Doug. For example: Do you have differential braking? Are you
looking through the windscreen so you can see and correct the
slightest swerve of the nose? Do you scale the crosswind component to
the landing speed? There are many differences.
O-ring
Edward Zager
SNIP
|>
|> I also think a better title for this thread would be 'PILOTS Subject
|> to Ground Looping'.
|>
|> All of the designs out there have been flown successfully by many
|> pilots without ground looping them. Also, experienced tailwheel
|> looking at a design just to minimize their chances of embarrasing
|> themselves, thay should either get some more dual or stay away from
|> airplanes altogether. And that includes ones with nosewheels too.
|> Especially those with retractable landing gear.
|>
I have to disagree.
The plane can be a major factor regardless of experience.
If you still disagree, show me any of the Me/(Bf) 109s (including the Merlin
engined) that are flying today that haven't had the gear ripped off at
least once from a ground loop.
All of these planes were flown by very experienced pilots.
With the narrow gear and small rudder all it takes is a good gust from the
wrong direction, the pilot won't matter.
Edward Zager Focke Wulf 149JZ
O-ring Seals
>On 21 Jan 2000 03:17:00 GMT, Doug Hoffman <dhof...@oakland-info.com>
>wrote:
>
>>In article <3887a268....@news.psnw.com> O-ring Seals,
>>vint...@eudoramail.com writes:
>>>I fail to see what model airplanes have to do with any of this.
>>>
>>
>>Why? Are the laws of physics, aerodynamics, etc. different for 25'
>>wingspans than for 10' wingspans (for example)?
>
Doug. A few more things to consider: Is the control
response/authority to scale? What about wing loading? Effectivness
of the landing gear? Thrust to weight ratio? Are all of the mass
dynamics also to scale? What about the coefficient of friction
between the tires and the landing surface? Be very cautious in
drawing parallels between models and full scale aircraft unless you do
a thorough analysis of these and many other parameters.
John Armbrust
quite handily) compensated for by pilot skill and experience. The good
designer is one that eliminates all human factor "gotchas" that would
require "undue pilot skill" to overcome. There aircraft of such poor design
that, sooner rather than later, an accident incident will happen. Case in
point- a high performance military fight (century series I believe) had the
drogue chute deployment handle and the gear handle (or was it flaps?) side
by side on the lower left panel, and were identical in size and shape. You
guessed it- short final (but not yet landed) the pilot reached up and
deployed the drogue. A safety board would conclude that it was pilot error,
but the reality is that the pilot was assisted in his or her error by piss
poor design.
--
John W. Armbrust
Test Pilot
Edward Zager <eza...@td2cad.KiLLSPam.intel.com> wrote in message
news:86aahq$n...@news.or.intel.com...
Adam M Carlson
Before you go out and start trying to bash your other fellow pilots, you
might want to look at some of the things that you listed to consider. For
example; the friction coefficient of the model rubber wheels and the full
sized rubber wheels will be nearly the same. Friction coefficients are not
based on size of the area in contact with the ground, but it is based on the
two materials that are in contact. Both tires being made from similar types
of rubber (and both are landing on asphalt, concrete, grass, or dirt) will
have such similar friction coefficients that the differences will be
negligible.
You mention wing loading... You are right that the wing loadings will not
be that same, but you are looking at a factor that is of no relevance. Wing
loadings will not scale down proportionally. Though if you look at the span
loading it will be fairly proportional, and is the factor that you need to
look at.
Thrust to weight ratio. What does this have to do with anything? ground
loops usually happen when an airplane is going relatively slow. i.e.
takeoff and landing. when an airplane is going fast the control authority
is such that it will overcome the tendencies to ground loop. In order to
ground loop an airplane going fast you will need to force it to do it. By
the way, there was an airplane that had the thrust to weight ratio of many
model airplanes. Have you ever heard of the Turbo Raven. The thrust to
weight ratio on this airplane is in the neighborhood of 2.5 to 1, and
happened to be a tailwheel aircraft.
Also, you do not need to scale the cross-wind component of the larger types
of models that are in the scale weight range. This is because a thing
called Reynolds numbers comes into effect. The smallest the chord of a
airfoil. The greater wind velocity is needed to equal the similar effect of
the airfoil with the larger chord.
By the way, are you a tailwheel pilot? If you are why are you mentioning
differential breaking? If you are using your breaks on a landing roll out,
I never want to fly with you. This is one of the most common causes of
ground loops. I do not care if you have been doing it for thousands of
hours, it is dangerous. Before you make the arbitrary statement about
breaks on scale models, you should do your homework more carefully. If you
did you would find that there are breaks available for large scale models.
Please do some research before you go out and bash your fellow pilots so
hastily.
Luscombe 8E pilot and RC pilot
Adam M Carlson
If scale airplanes are not good ways to judge larger scale airplanes, why
then are scale models used in wind tunnels? Are they spending hundreds of
millions of dollars on a fruitless venture? Things for thought.
O-ring Seals wrote in message <3888b341....@news.psnw.com>...
Adam M Carlson
Despite the fact that he has been flying tailwheel planes before I was born,
there are some fact that will apply no matter how long you have been flying.
As for him talking down to other pilots, all you have to do is read his last
two messages. There is a tone of negatively to them. I will stand by what
I say, because it is fact. As for people talking down to others, why would
you participate in this practice? I personally do not care how someone will
portray me, or what they say about me. I do not get offended that easily.
In my message I was stating the facts of the subject in a debate style
fashion. Some may not like this style; but when a person goes out and talks
down to another pilot, while using false facts I find it the most
appropriate method of getting the point across.
As for me hanging around the foundation for a few summers... It has taught
me many things, and I admit that I have many more things that I need to
learn. The same could be said for O-ring Seals in the modeling world.
Aerodynamics and structures have been my personal study for many years. I
am by no means an expert, but I do under stand many of the things to a great
degree. By the way. the people down at the foundation are only really my
relatives by friendship. I have no blood relation to Doug. Though, Doug
and the others have been a great inspiration to me, and continue to be.
Thanks for your thoughts Al, and I hope that you have a good evening 8^)
Adam
Alan Staats wrote in message <3888f635...@news.frontiernet.net>...
>On Fri, 21 Jan 2000 16:59:37 -0700, "Adam M Carlson"
><adam.c...@worldnet.att.net> wrote:
>
>...ummm, adam, o-ring has been flying tailwheels since before you were
>born, and probably knows a bit more about the subject than you have
>learned over the course of a few summers hanging aroung your relatives
>at the foundation. and, unlike you, i have NEVER seen him talk down
>to someone.
Alan Staats
dgam...@nbnet.nb.ca
Seals) wrote:
>
>I fail to see what model airplanes have to do with any of this.
>
>
>O-ring Seals
Ruh -roh.. ..
Sorry O-ring...
Models ground loop for the same reasons the full size ones
do.. poor design or the pilot... whatever..
They are aircraft regardless of whether the pilot is outside
flying it (more difficult BTW) or inside looking out...
Physics are the same and the size can be comparible , we are
not sure sometimes where the "model" stops and "full size" takes
over... (like how about a 36 FOOT span R/C model.. )
And I "toe in" my main wheels for resistance to the swerve
that develops into a ground loop.. once the "differential loading"
on the main wheels becomes significant .. the ground loop is well on
it's way...
I find with the wheels toed out , they are a bear to handle,
requiring MUCH skill to keep straight...
Cheers ! Dave
And yes, I have flown both inside and outside the planes,
outside since 1963 and inside since 1983... <G>
Scrappman
Ed Sullivan wrote:
> On Wed, 19 Jan 2000 20:39:36 -0500, J&D <jk...@planeteer.com> wrote:
>
> >Taildraggers with toe-in can be very squirrely. Taildraggers should be
> >zero or have a small amount of toe-OUT. With a taildragger, toe-in
> >aggravates the natural instability that is already there. Toe-out gives a
> >slight "crosswind gear" effect and tends to be stabilizing, the opposite
> >of the way it should be in a trike..
> >
> >JKahn
> >
> Also the tail wheel verticle shaft should be canted forward at the top a bit which tends to keep the tailwheel in trail.
>
> Ed
Wouldn't this make the ground handling harder at taxi?
Scrappman
Scrappman
the ground loop, forces the outboard gearup and out. Is this an advantage?
Scrappman
Mark Hickey wrote:
> e...@qnis.net (Ed Sullivan) wrote:
>
> >Also the tail wheel verticle shaft should be canted forward at the top a bit which tends to keep the tailwheel in trail.
>
Scrappman
a lake that is frozen, no snow, gives you a real feel for the aircraft,
also is good practice for float taxi. I realize that not everyone has
there lakes freeze,,,,,,,,some of us are just lucky...........
Scrappman
Scrappman
that will,,,,, and that will do it again,and again,and again..........
Scrappman
O-ring Seals wrote:
> On Thu, 20 Jan 2000 19:41:10 GMT, luc...@metrowerks.com wrote:
>
> >In article <864ujv$4e5$1...@cartero.kjsl.com>,
> > Frank Stutzman <stut...@stutzman.com> wrote:
> >
> >I had an R/C Skybolt (about 1/5 size) that was very prone to ground
> >looping.
> >
> >Lucien S.
> >PP-ASEL.
> >Captain America IV.
> >
> Captain America,
>
> I fail to see what model airplanes have to do with any of this.
>
> I also think a better title for this thread would be 'PILOTS Subject
> to Ground Looping'.
>
> All of the designs out there have been flown successfully by many
> pilots without ground looping them. Also, experienced tailwheel
> pilots have ground looped airplanes of all types. If anyone is
> looking at a design just to minimize their chances of embarrasing
> themselves, thay should either get some more dual or stay away from
> airplanes altogether. And that includes ones with nosewheels too.
> Especially those with retractable landing gear.
>
> O-ring Seals
Ed Sullivan
>
>
>
>> >
>> Also the tail wheel verticle shaft should be canted forward at the top a bit which tends to keep the tailwheel in trail.
>>
>> Ed
>
> Wouldn't this make the ground handling harder at taxi?
> Scrappman
>
I'm not recommending a lot, just avoid it being tilted to the rear when the weight is on the wheel.
Ed
Scrappman
Scrappman
Bruce A. Frank
>
> Also the tail wheel verticle shaft should be canted forward at the top a bit which tends to keep the tailwheel in trail.
>
> Ed
This seems logical but contridicts information that is true in other
"steerable wheel" application. The way to get automotive wheels to track
straight is to cant the top of the pivot towards the rear. The same is
true of bicycle front wheels. Canting the pivot forward of verticle
usually brings about instability and shimmy. The "trailing arm"
(tailwheel in trail) configuration of most tailwheel designs still
requires the steering pivot to be canted to the rear for tracking. Am I
mistaken?
Ed Sullivan
Bruce, I certainly won't say you are wrong.
I can only speak from my experience. I have had it both ways on my Jungster and on a Baby Lakes and my hangar partner's
Turner T-40 and I and we feel it is better as I described. I may be all wrong in theory and fact. I only do what works
for me.
Ed Sullivan
Mark Hickey
>Ed Sullivan wrote:
>> Also the tail wheel verticle shaft should be canted forward at the top a bit which tends to keep the tailwheel in trail.
>This seems logical but contridicts information that is true in other
>"steerable wheel" application. The way to get automotive wheels to track
>straight is to cant the top of the pivot towards the rear. The same is
>true of bicycle front wheels. Canting the pivot forward of verticle
>usually brings about instability and shimmy. The "trailing arm"
>(tailwheel in trail) configuration of most tailwheel designs still
>requires the steering pivot to be canted to the rear for tracking. Am I
>mistaken?
The reason it won't work in a motorcycle is because when you cant it
backward, the contact patch will be AHEAD of the axis of the fork - so
riding it would be kind of like trying to push a shopping cart rear
wheel backwards (very unstable).
Just trace a line through the "vertical shaft" to the ground. The
further the contact patch of the wheel is BEHIND that line, the more
stable the steering will be.
And, don't confuse the pivot with the trailing arm that holds on the
rear wheel on some AC - where it pivots is what counts, not the
structure holding the wheel on.
Mark Hickey
Charles K. Scott
"Bruce A. Frank" <BAFRANK@**SpamBlock**worldnet.att.net> writes:
> This seems logical but contridicts information that is true in other
> "steerable wheel" application. The way to get automotive wheels to track
> straight is to cant the top of the pivot towards the rear. The same is
> true of bicycle front wheels. Canting the pivot forward of verticle
> usually brings about instability and shimmy. The "trailing arm"
> (tailwheel in trail) configuration of most tailwheel designs still
> requires the steering pivot to be canted to the rear for tracking. Am I
> mistaken?
I used to do alignments in my automotive mechanic days Bruce and while
what you say seems logical, canting the suspension backward is actually
gaining positive castor. What you do is draw a line through the
suspension points to the ground, and draw a line vertically through the
center of the wheel. When you cant the suspension points with the top
one rear of the bottom one, the line through the suspension points
comes out ahead of the vertical line through the center of the wheel.
That's positive castor and most suspensions are set up this way.
Trailing arm suspension is a term used for fully articulated
suspensions in which the moving arm trails to the rear, rather than to
the side. Tail wheels thus aren't truly "trailing arms" because they
aren't articulated. They are set up the way they are to give positive
castor.
When you slant the wheel and also have positive castor, you in effect
are using the weight of the airplane to assist in the castor because
when the wheel is displaced to one side, the tail of the airplane
actually rises up due to the angle of the movement. The weight of the
airplane tries to force the tailwheel to "trail" or track straight to
the rear, whenever the airplane is moving forward.
Corky Scott
highflyer
>
> Ed Sullivan wrote:
> >
> > Also the tail wheel verticle shaft should be canted forward at the top a bit which tends to keep the tailwheel in trail.
> >
>
> This seems logical but contridicts information that is true in other
> "steerable wheel" application. The way to get automotive wheels to track
> straight is to cant the top of the pivot towards the rear. The same is
> true of bicycle front wheels. Canting the pivot forward of verticle
> usually brings about instability and shimmy. The "trailing arm"
> (tailwheel in trail) configuration of most tailwheel designs still
> requires the steering pivot to be canted to the rear for tracking. Am I
> mistaken?
>
Don't confuse static and dynamic stability. With a tailwheel we would
like
it to remain in line when the airplane is not moving. For this to
occur,
the tailwheel pivot shaft has to be aligned in such a way, that any
deflection of the tailwheel, in either direction, lifts the tail against
gravity. This will cause a turning moment on the tailwheel to cause it
to align at that position where the tail is lowest. Any more deflection
in either direction requires enough force to lift the tail be applied.
Dynamically, the contack point of the tailwheel with the runway has to
be behind the extended centerline of the pivot shaft. This causes the
friction drag of the tailwheel to keep it trailing behind the pivot.
It is simply a caster. It may be a caster with steering connections
that
make it possible to force it one way or another, out of the stable,
trail,
position. However, if you think of it as a free caster you will then
have a better idea of how to set it up for stability.
Remember, that even a caster can shimmy. Tailwheels are also known to
shimmy once in a while. Stopping shimmy in a caster usually requires
some damping that will prevent excitations from escalating to scary
levels. In most casters, this damping is provided by the natural
tightness
of the components. When the bushings wear, the tailwheel begins to be
more prone to shimmy. Some casters have a built in friction damper to
make sure that shimmy does not occur.
Some aircraft, like the Grumman American series, or even the early
Bonanzas, has a plain caster for a NOSE wheel. These castering nose
wheels have the same shimmy/shimmy damper problem as tailwheels.
--
HighFlyer
Highflight Aviation Services
highflyer
>
> > zero or have a small amount of toe-OUT. With a taildragger, toe-in
> > aggravates the natural instability that is already there. Toe-out gives a
> > slight "crosswind gear" effect and tends to be stabilizing, the opposite
> > of the way it should be in a trike..
> >
> > JKahn
>
>
> Assume that a plane with toe-in is disturbed slightly such that it is
> pointing slightly
> left of the direction it is moving. The left will will be better aligned
> with the direction
> of travel than the right wheel. I would think this would cause the right
> wheel to
> have more resistance than the left, creating a restoring moment. Therefore,
> the toe-in
> would help resist a ground-loop. Where does this logic go astray?
>
If there is toe in, the wheels extended path will cross the center line
of the airplane. Let's say the airplane starts to swerve to the left.
Since the center of gravity is well above the wheels, this transfers
weight to the right wheel, which is not pointer even farther to the left
than the airplane is. As a result of decreasing friction on the left
wheel, and increasing friction on the right wheel the "toed in" right
wheel tries to cause the airplane to turn to the left! This is NOT a
restoring moment, and aggravates the beginning swerve.
If you have "toe OUT" when this happens, the right wheel picks up more
loading and trys to turn the airplane to the RIGHT. Since it was
swerving
to the left to start with, this weight transfer induced swerve back to
the right is correcting and helps with the directional stability of the
airplane.
> On a related note, a friend of mine is looking into buying a Maule and the
> insurance
> companies he has talked to tell him that Maules have a very bad
> ground-looping
> record. Any comment on what it is about a Maule that could lead to this? Is
> this
> more a reflection of what type of pilot flies a Maule or what type of
> operation is
> typical in a Maule than it is a reflection of the design?
The Maule is actually very similiar to a "hopped up" Piper Pacer. Like
the Pacer it has a quite powerful and responsive rudder. When you take
this strong directional control characteristic and combine it with an
inexperienced and apprehensive pilot, the tendency is to seriously
overcorrect any directional variation on landing. This overcorrection
frequently leads to a groundloop induced by pilot action.
Actually, in my experience, I have always found the Maule's that I have
flown to be quite docile in ground handling. Much better than some of
the homebuilts I have flown! :-)
highflyer
<snipped a bunch of erroneous bullshit >
> By the way, are you a tailwheel pilot? If you are why are you mentioning
> differential breaking? If you are using your breaks on a landing roll out,
> I never want to fly with you. This is one of the most common causes of
> ground loops. I do not care if you have been doing it for thousands of
> hours, it is dangerous. Before you make the arbitrary statement about
> breaks on scale models, you should do your homework more carefully. If you
> did you would find that there are breaks available for large scale models.
>
If you try to tell me you are an experienced tailwheel pilot and you
have
NEVER used differential braking I KNOW you are a liar. You have clearly
demonstrated in your fallacious argument that you don't have any idea
what you are talking about.
> Please do some research before you go out and bash your fellow pilots so
> hastily.
>
You have best do some research yourself. You are not only way out of
line,
but you are way off base with your "research."
> Luscombe 8E pilot and RC pilot
> Adam M Carlson
>
> If scale airplanes are not good ways to judge larger scale airplanes, why
> then are scale models used in wind tunnels? Are they spending hundreds of
> millions of dollars on a fruitless venture? Things for thought.
Things for thought, indeed. If you bothered to read the posting you are
criticizing you have realized that nothing was said about models being
useless for aerodynamic testing. Merely that MANY factors have to be
understood and corrected. I do NOT know of ANY labs that use models for
anything other than aerodynamic evaluation, and then ONLY with serious
and
significant corrections using well known corrections factors that have
been empirically verified many times over the last one hundred or so
years of aircraft design.
By the way, I am certainly glad that the taildraggers I fly, including,
on occaision, one of those lovely and docile little Luscombes, DO have
differential braking. Even given that I rarely use brakes on landing
or takeoff.
highflyer
>
>
Lucien, I am certainly familiar with model airplanes. I am also
familiar
with the design and building of full size airplanes. Knowing something
about the physical principles involved, I might point out that there is
a limited set of physical principles that applies to EVERYTHING. That
does NOT mean that it is easy or trivial to extrapolate behavior from
a remotely controlled model to a full scale, pilot controlled airplane.
In fact, there are so many pitfalls and traps in the extrapolation of
the behavior between the two, that models are generally considered to
be only of use in limited applications where only those factors that
can be corrected for scale effects can be studied.
Analogies can be extremely dangerous when they are pushed beyond their
application. By definition, a model is an analogue.
highflyer
>
> Ruh -roh.. ..
>
> Sorry O-ring...
>
> Models ground loop for the same reasons the full size ones
> do.. poor design or the pilot... whatever..
>
> They are aircraft regardless of whether the pilot is outside
> flying it (more difficult BTW) or inside looking out...
>
> Physics are the same and the size can be comparible , we are
> not sure sometimes where the "model" stops and "full size" takes
> over... (like how about a 36 FOOT span R/C model.. )
>
> And I "toe in" my main wheels for resistance to the swerve
> that develops into a ground loop.. once the "differential loading"
> on the main wheels becomes significant .. the ground loop is well on
> it's way...
>
> I find with the wheels toed out , they are a bear to handle,
> requiring MUCH skill to keep straight...
>
> Cheers ! Dave
>
> And yes, I have flown both inside and outside the planes,
> outside since 1963 and inside since 1983... <G>
Sorry Dave. You proved yourself WRONG. If, indeed, toe in makes a
model easier to land, that only indicates a profound difference
between models and real airplanes.
Probably the squirliest and most exciting airplane to land that I
have ever flown was a Pitt's Special that was built with one degree
of "toe in" on the main gear. We were about to give up on ANYone
being able to safely fly the darn thing.
Then I started to think about "toe in" and "toe out." We went back and
bent the gear to convert the one degree of "toe in" into about one
degree of "toe out."
What happened? All of a sudden the airplane tracked like a ruler on
roll out. Anybody could land the darn thing. It was unbelieveable
what a drastic difference in ground handling resulted when we changed
the main gear from a smidge of "toe in" to a smidge of "toe out."
If you check with any experienced aircraft designer, you will find that
the usual tolerance for track on the main gear is "parallel, with a
tolerance of zero toe in, and a degree or two of toe OUT.
CRS
I tend to agree with your logic, but I also know that in the case of a car
pulling a trailer, this just doesn't work the way logic says it should. A
trailer must have toe-in or it weaves all over the place, and it is the same
logic of weight on the wheel would make it swerve to the other side, etc.
There must be some other factors involved.
--
UtahDoug
------------------------------
highflyer <high...@alt.net> wrote in message
luc...@metrowerks.com
high...@alt.net wrote:
> luc...@metrowerks.com wrote:
> >
> > > I fail to see what model airplanes have to do with any of this.
> >
> > Same physical principles involved. Believe it.... Or not.....
> >
> >
>
> Lucien, I am certainly familiar with model airplanes. I am also
> familiar
> with the design and building of full size airplanes. Knowing
something
> about the physical principles involved, I might point out that there
is
> a limited set of physical principles that applies to EVERYTHING. That
> does NOT mean that it is easy or trivial to extrapolate behavior from
> a remotely controlled model to a full scale, pilot controlled
airplane.
Boy, all this about my little biplane.......
Oh, well, I _thought_ they were the same principles anyway... I trust
you, though, since you've a lot more knowledge about it than I, and
stand corrected on any erroneous statements I've made.
I do remember that little Skybolt was a stick-full to takeoff and land,
I'll put it that way 8). Still, I kind of regret I sold it, now that I
think about it.....
> In fact, there are so many pitfalls and traps in the extrapolation of
> the behavior between the two, that models are generally considered to
> be only of use in limited applications where only those factors that
> can be corrected for scale effects can be studied.
>
> Analogies can be extremely dangerous when they are pushed beyond their
> application. By definition, a model is an analogue.
Back to the books for me, then ;-). Speaking of which, where would a
Cub sit on the scale of easy-to-ground loop vs. less-easy-to-ground
loop? I may get tailwheel training in one.
Lucien S.
PP-ASEL.
Captain America IV.
> --
> HighFlyer
> Highflight Aviation Services
>
Sent via Deja.com http://www.deja.com/
Before you buy.
Scrappman
has been many times that it would have been nice. Due to the low stall speeds,
full flap landings can be done with little or no breaking at all. But no flap
landings need considerable more talent from the pilot. The rudder throw is 35
deg.each way, transferred to a 3 1/2 in throw on the peddles. Practice is the
answer to preventing, or tolerating ground loops. After a while you can do one
anytime you want and not do any damage to the airframe.
Scrappman
highflyer wrote:
Reid and Julie Baldwin
would have the opposite effect of a tailwheel aircraft.
"CRS" <sher...@uswest.net> wrote in message
news:vG2j4.552$Ed.2...@news.uswest.net...
dgam...@nbnet.nb.ca
wrote:
>
>
>
>Sorry Dave. You proved yourself WRONG. If, indeed, toe in makes a
>model easier to land, that only indicates a profound difference
>between models and real airplanes.
Nope... didn't say ALL aircraft had to be that way... designs
vary... I know of one model that worked better "toe Out"
>What happened? All of a sudden the airplane tracked like a ruler on
>roll out. Anybody could land the darn thing. It was unbelieveable
>what a drastic difference in ground handling resulted when we changed
>the main gear from a smidge of "toe in" to a smidge of "toe out."
Interesting...
>
>If you check with any experienced aircraft designer, you will find that
>the usual tolerance for track on the main gear is "parallel, with a
>tolerance of zero toe in, and a degree or two of toe OUT.
At rest or on level attitude... and how about "camber"
I will check... a friend with a Citabria says his are toed in
.. also a 170 driver I spoke to...
Curious...
Thanks for your reply!
Dave
Mark Hickey
> Due to the low stall speeds,
>full flap landings can be done with little or no breaking at all.
Well I certainly hope so....
Mark Hickey
assa9
Where the landing gear rod bends around the corner and becomes the axle, it
is only 5/8 ths in diameter.
This allows the wheel to shake anywhere it wants to while landing.
The wheels are a blur, as they shake several degrees toe-i and toe-ouy,
+ camber and - camber.
Because of this , or in spite of this, the Tailwind is the easiest airplane
to land that I have ever been in.
Mine was in a hangar collapse, and the left landing gear is still bent up in
such
a manner that the airplane leans to the left by a lot. It is still the
easiest airplane to land.
It will be at the RAH fly-in, as it has for the last two. And I am sure the
gear will still be bent.
assa9
<dgam...@nbnet.nb.ca> wrote in message
news:388d23a0...@news.nbnet.nb.ca...
David B. Schober
tailwheel springs rebent to move the pivot axis so it is inclined aft to resolve tailwheel shimmy problems.
Ed Sullivan wrote:
> On Sun, 23 Jan 2000 18:14:29 -0800, "Bruce A. Frank" <BAFRANK@**SpamBlock**worldnet.att.net> wrote:
>
> >Ed Sullivan wrote:
> >>
> >> Also the tail wheel verticle shaft should be canted forward at the top a bit which tends to keep the tailwheel in trail.
> >>
> >> Ed
> >
> >This seems logical but contridicts information that is true in other
> >"steerable wheel" application. The way to get automotive wheels to track
> >straight is to cant the top of the pivot towards the rear. The same is
> >true of bicycle front wheels. Canting the pivot forward of verticle
> >usually brings about instability and shimmy. The "trailing arm"
> >(tailwheel in trail) configuration of most tailwheel designs still
> >requires the steering pivot to be canted to the rear for tracking. Am I
> >mistaken?
George R Patterson
>
> Highflyer,
>
> I tend to agree with your logic, but I also know that in the case of a car
> pulling a trailer, this just doesn't work the way logic says it should. A
> trailer must have toe-in or it weaves all over the place, and it is the same
> logic of weight on the wheel would make it swerve to the other side, etc.
No, the trailer follows the same physics as a trike. When the trailer
swings out, the weight will shift to the outside wheel, which then tends
to bring that side back towards the center. A taildragger is sort of
like a trailer that is being backed up.
George Patterson, N3162Q.
J&D
They have toe-in because the flexibility of the steel gear legs makes them
natually toe-out as drag loads flex the legs while rolling, and if there was
already toe-out it would become excessive. The ideal is no more than 3
degrees. I have read that "Texas Taildragger" conversions of 150s with the
tubular gear can be squirrely because the tubular gear likes to flex in all
directions and the toe-in/out is all over the place.
Tony Bengalis has written some articles about wheel alignment in Sport
Aviation that explain the need for toe-out.
JKahn
Scrappman
wind,,,,,,,,,,,,,,,,,(hehehe)
Scrappman
Scrappman
Scrappman
"John W. Hart" wrote:
> Breaking OR Braking???????????? Oh, welllllll.
> John
>
> "Scrappman" <rap...@microassist.com> wrote in message
> news:388F8B91...@microassist.com...
John W. Hart
highflyer
>
>
> Boy, all this about my little biplane.......
>
> Oh, well, I _thought_ they were the same principles anyway... I trust
> you, though, since you've a lot more knowledge about it than I, and
> stand corrected on any erroneous statements I've made.
>
> I do remember that little Skybolt was a stick-full to takeoff and land,
> I'll put it that way 8). Still, I kind of regret I sold it, now that I
> think about it.....
>
I was a good friend of Lamar Steen and when he was designing the
original
Skybolt, I assisted him with the aerodynamic design. He did credit me
with the responsibility for the flying qualities of the airplane. He
did all of the structural design himself.
> > In fact, there are so many pitfalls and traps in the extrapolation of
> > the behavior between the two, that models are generally considered to
> > be only of use in limited applications where only those factors that
> > can be corrected for scale effects can be studied.
> >
> > Analogies can be extremely dangerous when they are pushed beyond their
> > application. By definition, a model is an analogue.
>
> Back to the books for me, then ;-). Speaking of which, where would a
> Cub sit on the scale of easy-to-ground loop vs. less-easy-to-ground
> loop? I may get tailwheel training in one.
As taildraggers go, the Cub is the Cessna 150 of taildraggers. Anyone
can safely fly either a Cub or a Champ. A T-Cart can require a little
more precision, just because it doesn't slow down as easily in ground
effect. None of those will adequately prepare you to go jump into
something like a T-6 or a Staggerwing Beech.
highflyer
>
> Highflyer,
>
> I tend to agree with your logic, but I also know that in the case of a car
> pulling a trailer, this just doesn't work the way logic says it should. A
> trailer must have toe-in or it weaves all over the place, and it is the same
> logic of weight on the wheel would make it swerve to the other side, etc.
>
>
On the contrary, it is working exactly the same way. Toe in would
be correct for the airplane also when the landing gear are located
BEHIND the center of gravity as they are on a tricycle gear aircraft
or on a two wheel trailer towed behind a car.
Think about the direction the restoring moment has to be to cancel
the swerve.
luc...@metrowerks.com
high...@alt.net wrote:
> luc...@metrowerks.com wrote:
> Lucien,
>
> I was a good friend of Lamar Steen and when he was designing the
> original
> Skybolt, I assisted him with the aerodynamic design. He did credit me
> with the responsibility for the flying qualities of the airplane. He
> did all of the structural design himself.
Well, if the big one flew like the model one I had, ya'll did a good
job 8). Mine was a 1/5scale model made by a company called Great Planes
and was built by a good friend of mine. It was hideously overpowered
with a Saito 1.50 4-cycle alcohol burner and would go straight up pure
vertical at 3/4 throttle.....
I'm assuming it is out of production now?
> > Back to the books for me, then ;-). Speaking of which, where would a
> > Cub sit on the scale of easy-to-ground loop vs. less-easy-to-ground
> > loop? I may get tailwheel training in one.
>
> As taildraggers go, the Cub is the Cessna 150 of taildraggers. Anyone
> can safely fly either a Cub or a Champ. A T-Cart can require a little
> more precision, just because it doesn't slow down as easily in ground
> effect. None of those will adequately prepare you to go jump into
> something like a T-6 or a Staggerwing Beech.
As I wrote to you a while back, I was considering a Taylorcraft for
ownership, but now looks like I'll be buying into a 150 instead (one
day I plan to fly it to ya'lls flyin at Pinkneyville). I still want to
get tailwheel training, but the Cub looks like the only game in town
around here.....
Lucien S.
PP-ASEL.
Captain America IV.
highflyer
>
> My experiance with Champs, Cubs, Stinsons, and the like is to have the axis of the pivot canted aft. I've had countless
> tailwheel springs rebent to move the pivot axis so it is inclined aft to resolve tailwheel shimmy problems.
>
I also have noticed that repeated diligent assertive applications of
B.D. Maules recommended "double whomp" tailwheel first landing
technique has a regrettable tendency to recurve the tailwheel spring
in a way that is remarkably conducive to tailwheel shimmy! :-)
jack
> Braking needed to stop from rolling backwards....
Don't!
Use engine power. Otherwise you'll put it on the tail.
Jack
--
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===|=====|=====|=====|=====|===
©1998 nAsgrp.com
____________________________________________
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Michael
> Braking needed to stop from rolling backwards....
jack <working_w/o...@dot.net> wrote
>Don't!
>Use engine power. Otherwise you'll put it on the tail.
Of course in some aircraft that is the preferred method.
Just trying to get back on topic...
Michael
Brian Rauchfuss - PCD
Adam M Carlson <adam.c...@worldnet.att.net> wrote:
>...
>
>Thrust to weight ratio. What does this have to do with anything? ground
>loops usually happen when an airplane is going relatively slow. i.e.
A blast of thrust can be used to straighten out an incipient ground-
loop. This becomes less and less effective as the thrust to weight
ratio goes down.
>By the way, are you a tailwheel pilot? If you are why are you mentioning
>differential breaking? If you are using your breaks on a landing roll out,
When I learned to fly tailwheel, I was taught to use differential breaking
as a last resort to prevent a groundloop. I probably use it once every 10
landings to stay straight.
Brian
Brian Rauchfuss - PCD
><snip>
>
>By the way, I am certainly glad that the taildraggers I fly, including,
>on occaision, one of those lovely and docile little Luscombes, DO have
>differential braking. Even given that I rarely use brakes on landing
>or takeoff.
>
>HighFlyer
>Highflight Aviation Services
HighFlyer, a slight change of topic: I am building a Europa, which happens
to be a taildragger without differential breaking (monowheel). I occasionally
need to use breaking with the Cub I fly, but usually because the tailwheel
has broken loose and will no longer give me directional control. The Europa
tailwheel does not give way unpredicably.
What do you think of the combination of no differential breaking but a
reliable tailwheel?
Brian
Scrappman
taxi,,,,to a stop with the tail up....
Scrappman
jack wrote:
> Scrappman wrote:
>
> > Braking needed to stop from rolling backwards....
>
> Don't!
>
> Use engine power. Otherwise you'll put it on the tail.
>
highflyer
Hi Brian,
I don't think there is such a thing as a reliable tailwheel! :-)
Actually there are about four different ways to make a tailwheel.
Many of the airplanes I fly do NOT have any "steering" links to the
tailwheel. SOME, not mine, have a hardened pin that you can drop
into the tailwheel to "lock" it straight. These usually help to
keep the airplane straight, although as they wear they generally
do allow a few degrees of freedom. This freedom is usually coupled
with a total lack of control! :-) On my airplane, the tailwheel is
just a big caster. It works well, but contributes NOTHING to
directional control.
Most light general aviation aircraft use a "steerable" tailwheel.
A few use a simple tailwheel that is merely pivoted so it can be
turned relative to the fuselage. The steering cables are attached
to the rudder control system and the tailwheel turns with the
rudder. This arrangement is quite positive, but can be a bit
tricky sometimes in a brisk crosswind when you touch down with
significant rudder deflection. It also limits your turning radius
on the ground quite severely. It is the cheapest steerable setup.
By far the majority of light tailwheel aircraft use a modified
steerable tailwheel that has a locking mechanism that locks it
straight ahead. Some lock when you put tension on BOTH cables
at the same time. These are fairly positive about their lock.
Most use a "detent" mechanism that keeps the tailwheel properly
in trail unless it sees a significant sideforce. Then it pops
out of the detent. This type allows you to easily make tight
turns on the ground by applying differential braking. Unfortunately,
it is exactly this "side force" that you are relying upon to help
keep tail excursions under control on roll out. A brisk swerve will
often cause these tailwheels to pop out of the detent and turn into
a caster just when you most need their help to stay straight.
Differential braking is of most value in any taildragger for ground
handling. I could not taxi my airplane in a crosswind without using
differential braking, because the flight surfaces don't have enough
power at walking speeds to overcome a brisk breeze. My old SeaBee
and all of the Beech 18's that I have flown had a locking tailwheel.
There was a lever in the cockpit that would drop the pin into the
tailwheel and lock it straight ahead. There was always just enough
play in the system that a cross wind taxi proceeded in a series of
long arcs curving into the wind. When you reached the upwind edge
of the taxiway, you would have to unlock the tailwheel, lock up one
brake, and do about a 300 degree turn. Then you drop the lock pin
back in and do another long arc! It was strange to watch, but it
did work.
The only aircraft I have flown with monowheel gear were gliders.
Generally the rudder on a glider is quite effective down to low
airspeeds. Most, when landing in a crosswind, would end their
landing roll with an uncontrolled turn into the wind. Sort of a
tamed groundloop. :-) Of course, they generally had a substantial
skid in front of the wheel so you could use a bit of forward stick
to drag the skid on the grass for braking. They also had skids
under the wingtips to prevent damage when those long wings touched
the grass.
The monowheel Europa would be an interesting application for a
castering main gear! Having flown Cessnas with castering gear,
I know it is a bit unnerving to be rolling down the runway sideways
with only flight controls and power for directional control. Because
of that, virtually all of the Cessna owners I know who have the
castering gear on their aircraft, keep them locked straight and fly
them like conventional gear.
highflyer
> As I wrote to you a while back, I was considering a Taylorcraft for
> ownership, but now looks like I'll be buying into a 150 instead (one
> day I plan to fly it to ya'lls flyin at Pinkneyville). I still want to
> get tailwheel training, but the Cub looks like the only game in town
> around here.....
>
You can do far worse than a Cub for learning to land tailwheel
airplanes.
It will teach you a LOT about flying without scaring you too badly. :-)
Even the little Cub can teach you to make you approachs high on
purpose so that you can slip down final. When you are soloing from
the back seat there is a lot of "stuff" in front of you and it is a
LOT easier to see the runway if you slip a little! :-)
David Glauser
wrote:
<much good stuff snipped>
>Most light general aviation aircraft use a "steerable" tailwheel.
>A few use a simple tailwheel that is merely pivoted so it can be
>turned relative to the fuselage. The steering cables are attached
>to the rudder control system and the tailwheel turns with the
>rudder. This arrangement is quite positive, but can be a bit
>tricky sometimes in a brisk crosswind when you touch down with
>significant rudder deflection. It also limits your turning radius
>on the ground quite severely. It is the cheapest steerable setup.
>
The Europa uses the setup you describe above. The original Europa used
a setup where the rudder cables went directly to the tailwheel and
then a spring-loaded cable ran from there to the rudder. This made for
a few interesting moments on each landing and takeoff when the pilot
lifted or lowered the tail and had to transition between wheel
steering (small rudder movements at the relatively high speed) and
full aerodynamic steering (BIG rudder movements).
Later Europas (the XS model, and an available retrofit) use a linkage
from the pedals to the rudder, with spring-loaded links from there to
the wheel. Made all the difference on the ground.
BTW - highest demonstrated crosswind so far is 28 knots.
David
N82GT
Scrappman
Scrappman
John M. Kelly
Can't we stick to saying that, for instance, a KR2 for example would be a
harder tailwheel than a J3 Cub? As with all airplanes, all tailwheel
airplanes aren't created/designed equal.
J
Adam M Carlson wrote in message <86arci$89a$1...@bgtnsc01.worldnet.att.net>...
>O-ring Seals,
>
>Before you go out and start trying to bash your other fellow pilots, you
>might want to look at some of the things that you listed to consider. For
>example; the friction coefficient of the model rubber wheels and the full
>sized rubber wheels will be nearly the same. Friction coefficients are not
>based on size of the area in contact with the ground, but it is based on
the
>two materials that are in contact. Both tires being made from similar
types
>of rubber (and both are landing on asphalt, concrete, grass, or dirt) will
>have such similar friction coefficients that the differences will be
>negligible.
>
>You mention wing loading... You are right that the wing loadings will not
>be that same, but you are looking at a factor that is of no relevance.
Wing
>loadings will not scale down proportionally. Though if you look at the
span
>loading it will be fairly proportional, and is the factor that you need to
>look at.
>
>Thrust to weight ratio. What does this have to do with anything? ground
>loops usually happen when an airplane is going relatively slow. i.e.
>takeoff and landing. when an airplane is going fast the control authority
>is such that it will overcome the tendencies to ground loop. In order to
>ground loop an airplane going fast you will need to force it to do it. By
>the way, there was an airplane that had the thrust to weight ratio of many
>model airplanes. Have you ever heard of the Turbo Raven. The thrust to
>weight ratio on this airplane is in the neighborhood of 2.5 to 1, and
>happened to be a tailwheel aircraft.
>
>Also, you do not need to scale the cross-wind component of the larger types
>of models that are in the scale weight range. This is because a thing
>called Reynolds numbers comes into effect. The smallest the chord of a
>airfoil. The greater wind velocity is needed to equal the similar effect
of
>the airfoil with the larger chord.
>
>By the way, are you a tailwheel pilot? If you are why are you mentioning
>differential breaking? If you are using your breaks on a landing roll out,
>I never want to fly with you. This is one of the most common causes of
>ground loops. I do not care if you have been doing it for thousands of
>hours, it is dangerous. Before you make the arbitrary statement about
>breaks on scale models, you should do your homework more carefully. If you
>did you would find that there are breaks available for large scale models.
>
>Please do some research before you go out and bash your fellow pilots so
>hastily.
>
>Luscombe 8E pilot and RC pilot
>Adam M Carlson
>
>If scale airplanes are not good ways to judge larger scale airplanes, why
>then are scale models used in wind tunnels? Are they spending hundreds of
>millions of dollars on a fruitless venture? Things for thought.
>O-ring Seals wrote in message <3888b341....@news.psnw.com>...
>>
>>>On 21 Jan 2000 03:17:00 GMT, Doug Hoffman <dhof...@oakland-info.com>
>>>wrote:
>>>
>>>>In article <3887a268....@news.psnw.com> O-ring Seals,
>>>>vint...@eudoramail.com writes:
>>>>>I fail to see what model airplanes have to do with any of this.
>>>>>
>>>>
>>>>Why? Are the laws of physics, aerodynamics, etc. different for 25'
>>>>wingspans than for 10' wingspans (for example)?
>>>
>>
>>Doug. A few more things to consider: Is the control
>>response/authority to scale? What about wing loading? Effectivness
>>of the landing gear? Thrust to weight ratio? Are all of the mass
>>dynamics also to scale? What about the coefficient of friction
>>between the tires and the landing surface? Be very cautious in
>>drawing parallels between models and full scale aircraft unless you do
>>a thorough analysis of these and many other parameters.
>>
>>O-ring
>>
>>>>The use of models can be a cheap and safe way to to study the
>>>>extremes of CG and so forth.
>>>>
>>>>-Doug (who has flown both full scale and r/c models)
>>>
>>
>
>
highflyer
>
> OK ya'll,
>
> Can't we stick to saying that, for instance, a KR2 for example would be a
> harder tailwheel than a J3 Cub? As with all airplanes, all tailwheel
> airplanes aren't created/designed equal.
>
We could stick to saying that, but it probably wouldn't be very
accurate.
I have flown KR2's that were extremely easy to land. I have flown Cubs
that were easy to land and Cubs that were a handful. Airplanes, even
airplanes built to the same design, are individuals. Each has its own
personality that is a result of many small variations as it is built,
or often rebuilt. I have seen Cessna 172's that were WORK to fly, and
I have seen Cessna 172's that literally flew themselves.
Even my own Stinson Reliant I have trimmed out and flown hands off for
hours at a time. Minor changes in rig or production tolerances can
make big differences in the way an airplane flies.
John M. Kelly
opinion.
What's a Stinson Reliant? I've flown a 108-3, but I'm not sure what a
reliant is.
J
"highflyer" <high...@alt.net> wrote in message
news:3895C651...@alt.net...
highflyer
>
> I could imagine that most KR/Dragonfly/Quickie pilots would have a different
> opinion.
>
> What's a Stinson Reliant? I've flown a 108-3, but I'm not sure what a
> reliant is.
>
Eddie was killed in a plane crash. The last Stinson Reliant was built
for the Army Air Corps in 1943 at an AT-19.
The Reliant was famous because of its sensuous wing shape and it
large radial engine. It is a much larger airplane than the little
post war 108 series.
You can see a picture of me in my Reliant on a short final at
H. Brandon's private grass strip in Murray, Kentucky on the top of
the flyin web page at http://aviator.cwis.siu.edu/flyin