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Mike
July 22nd 03, 04:19 AM
I've read the term ground loop in a lot of articles and accident reports but
what exactly is a ground loop?

--Mike

Guy Elden Jr.
July 22nd 03, 04:47 AM
"Mike" > wrote in message
...
> I've read the term ground loop in a lot of articles and accident reports
but
> what exactly is a ground loop?

I'm sure somebody can provide a textbook definition, but my general
understanding is that it is an abrupt turn of an aircraft moving at a fairly
excessive rate of speed. I imagine something like this happening, for
instance, if one were landing in a Piper Warrior with a pretty full
deflection of the rudder and one didn't straighten it out before the
nosewheel touched the ground... the nosewheel moves as the rudder does,
unlike a C-172, which has a spring actuated bungee mechanism to turn the
nosewheel.

--
Guy Elden Jr.
PP-ASEL

Kyle Boatright
July 22nd 03, 04:53 AM
"Mike" > wrote in message
...
> I've read the term ground loop in a lot of articles and accident reports
but
> what exactly is a ground loop?
>
> --Mike

Take a shopping cart. Push it backwards across a parking lot or down the
grocery store aisle and release it. At some point, it is likely to do a
rapid piroutte. If it was an airplane instead of a shopping cart, that
would have been a groundloop.

Groundloops can apply very high forces to landing gear, tearing up the gear
and/or overturning the aircraft. Generally, they happen in tailwheel
aircraft.

KB

john smith
July 22nd 03, 04:57 AM
Mike wrote:
> I've read the term ground loop in a lot of articles and accident reports but
> what exactly is a ground loop?

A ground loop is what happens when a taildragger pilot isn't fast enough
on the rudder pedals to keep the tail from passing him/her while going
down the runway.
Because the center of gravity is behind the main landing gear on a
taildragger, the tail of the airplane wants to swing around to the
front.
The center of gravity is forward of the main gear on a tricycle gear
airplane, so the nose wants to stay out in front.

Grumman-581
July 22nd 03, 06:12 AM
A ground loop is an inadvertant maneuver that allows you to visits parts of
the airport that you never knew existed before...

C J Campbell
July 22nd 03, 07:15 AM
"BTIZ" > wrote in message
news:g03Ta.12456$Je.2196@fed1read04...
| and that's why tail dragger pilots have "happy feet"..
|
| never heard of a nose wheel aircraft "ground looping", the CG location
| relative to the main gear kinda help keep it straight..
|

One of the most common accidents in the Cessna 172 RG Cutlass is the ground
loop.

I have seen a Cessna 152 after it ground looped -- tore the nose gear off
and bent one of the mains. We called it the Cessna 152 RG.

I also saw a Cessna 172 SP that was struck by a Cessna 172 N that ground
looped.

I have heard of Mooneys ground looping, but never seen one.

Cub Driver
July 22nd 03, 11:33 AM
>I imagine something like this happening, for
>instance, if one were landing in a Piper Warrior with a pretty full
>deflection of the rudder and one didn't straighten it out before the
>nosewheel touched the ground..

In a Piper Cub or another taildragger, the ground loop is most often
begun when sloppy rudder inputs, a gust of wind, or even P factor
causes the aircraft to veer. As with a VW Beetle with the engine in
the rear (or a Corvair, for that matter), once the vehicle begins to
swap ends, it happens very fast, and it's very difficult to recover
from.

It can happen on takeoff as well as on landing.

A ground loop is most dangerous in a low-wing aircraft, where
centrifugal force causes the outside wing to dip, possibly dragging on
the ground.


all the best -- Dan Ford
email: www.danford.net/letters.htm#9

see the Warbird's Forum at http://www.danford.net/index.htm
Vietnam | Flying Tigers | Pacific War | Brewster Buffalo | Piper Cub

journeyman
July 22nd 03, 02:16 PM
On Mon, 21 Jul 2003 23:19:57 -0400, Mike > wrote:
>I've read the term ground loop in a lot of articles and accident reports but
>what exactly is a ground loop?

As others have pointed out, it's when a plane on the ground
uncontrollably does a 180. It usually starts with a swerve, typically
due to a gust of wind.

In a taildragger, picture your favorite shopping cart pushed backward,
the center of gravity is behind the main wheels. If you draw a
diagram of the forces, you'll see that the momentum vector will tend
to cause the tail to tend to continue swinging out after a swerve.
After a certain point, the CG will be outside the wheel and there's
nothing you can do to stop it from continuing to swing around. This
tends to be hard on the landing gear and wingtips. You want to keep
the momentum vector between the wheels if you want to stay in control.

There's an old-timer/instructor at The Place I Used To Rent From (whom
I never had the chance to fly with, unfortunately) who intentionally
groundloops the tailwheel on a grass runway (easier on the landing gear)
and at slow speeds (less likely to tip over). Good training exercise
if you're with someone who knows what he's doing (Rev definitely knows
what he's doing).

In the Olden Days, when aircraft didn't have brakes and you just landed
in any convenient field, groundlooping was how they stopped. In an
emergency, it may be a better choice than hitting something hard and/or
expensive.

Ground maneuvering in a tricycle-gear airplane is more stable The
mains are behind the CG and inertia will tend to straighten it out.
As mentioned, it is still possible to ground loop a nosedragger. One
of the easiest ways is to touch down nosewheel first on landing.


Morris

kevin
July 22nd 03, 03:55 PM
I've ground looped my Kitfox 5 twice and nothing happened to the plane
at all, no damage and no wing strike. Just a real quick 180 and now
looking at the plane behind me. I don't know if I got lucky or if the
plane just skids really well...

Big John
July 22nd 03, 05:30 PM
Mike

You have received lots of convoluted explanations of a 'ground loop'.
The simple explanation is it is when the pointy end not longer points
down the R/W on/after landing.

It's sometimes known as Oooops!

Big John

On Mon, 21 Jul 2003 23:19:57 -0400, "Mike" > wrote:

>I've read the term ground loop in a lot of articles and accident reports but
>what exactly is a ground loop?
>
>--Mike
>

Maule Driver
July 22nd 03, 05:33 PM
"Cub Driver" > wrote in message
...
> In a Piper Cub or another taildragger, the ground loop is most often
> begun when sloppy rudder inputs, a gust of wind, or even P factor
> causes the aircraft to veer. As with a VW Beetle with the engine in
> the rear (or a Corvair, for that matter), once the vehicle begins to
> swap ends, it happens very fast, and it's very difficult to recover
> from.
>
I like the rear engine analogy. Difference between the Beetle and the
Corvair seems to have been that the Beetle didn't suffer from 'ground
loops' very frequently. The Corvair was looking for them. My father owned
3 or 4 of them. In #3, we did the classic Corvair 'ground loop' plus some.
I'm not sure to this day how many times we went around but I do know we
ended up upside down on the convertible roof. Unsafe at any speed indeed!
The Vdub bus seems to be immune too. Drove 3 of them in western PA snows
and never had them try to swap ends. Passed a lot of stuck people too. But
of course, they were one of the most lethal vehicles on the road. They
weren't in a lot of accidents, but you stood a good chance of buying it if
when they were.

G.R. Patterson III
July 22nd 03, 06:42 PM
Maule Driver wrote:
>
> They [VW vans] weren't in a lot of accidents, .....

That's only because there weren't very many cars on the road that you
could catch if you were driving one.

George Patterson
The optimist feels that we live in the best of all possible worlds. The
pessimist is afraid that he's correct.
James Branch Cavel

G.R. Patterson III
July 22nd 03, 06:45 PM
Maule Driver wrote:
>
> Does the inside or outside wing tend to hit the ground once a ground loop is
> underway?

The outside wing.

George Patterson
The optimist feels that we live in the best of all possible worlds. The
pessimist is afraid that he's correct.
James Branch Cavel

G.R. Patterson III
July 22nd 03, 06:48 PM
Big John wrote:
>
> It's sometimes known as Oooops!

Gordon Baxter used to say that the method for handling a ground loop in a
Stearman is to look straight ahead, turn loose of the stick, throw your
hands over your head, and yell as loud as you can "OH SH*T!".

George Patterson
The optimist feels that we live in the best of all possible worlds. The
pessimist is afraid that he's correct.
James Branch Cavel

Maule Driver
July 22nd 03, 06:55 PM
"G.R. Patterson III" > wrote in message
...
> >
> > They [VW vans] weren't in a lot of accidents, .....
>
> That's only because there weren't very many cars on the road that you
> could catch if you were driving one.
>
But you didn't need cruise control. Just floor it. Tailwinds help too.

Dave Stadt
July 22nd 03, 09:44 PM
"john smith" > wrote in message
...
> Mike wrote:
> > I've read the term ground loop in a lot of articles and accident reports
but
> > what exactly is a ground loop?
>
> A ground loop is what happens when a taildragger pilot isn't fast enough
> on the rudder pedals to keep the tail from passing him/her while going
> down the runway.
> Because the center of gravity is behind the main landing gear on a
> taildragger, the tail of the airplane wants to swing around to the
> front.
> The center of gravity is forward of the main gear on a tricycle gear
> airplane, so the nose wants to stay out in front.

Nose draggers make wonderful groundloopers and the repairs are much more
costly than when a taildragger ground loops.

G.R. Patterson III
July 22nd 03, 10:24 PM
Dave Stadt wrote:
>
> Nose draggers make wonderful groundloopers and the repairs are much more
> costly than when a taildragger ground loops.

Yes, but it takes a lot of skill to be able to groundloop a nosedragger;
you almost have to work at it. Anybody can do it in a taildragger without
hardly trying.

George Patterson
The optimist feels that we live in the best of all possible worlds. The
pessimist is afraid that he's correct.
James Branch Cavel

Ron Natalie
July 22nd 03, 10:32 PM
"Mike" > wrote in message ...
> I've read the term ground loop in a lot of articles and accident reports but
> what exactly is a ground loop?
>
It's a problem in the wiring that tends to cause a hum in the radios.

BTIZ
July 23rd 03, 01:01 AM
the outside wing will hit... with our Pawnee, the inside wing can drag.. and
then as you "high side" (motorcycle talk) the outside wing can contact the
ground.. or if you've ever rolled a jeep when you get it side ways..

BT

"G.R. Patterson III" > wrote in message
...
>
>
> Maule Driver wrote:
> >
> > Does the inside or outside wing tend to hit the ground once a ground
loop is
> > underway?
>
> The outside wing.
>
> George Patterson
> The optimist feels that we live in the best of all possible worlds. The
> pessimist is afraid that he's correct.
> James Branch Cavel

BTIZ
July 23rd 03, 01:05 AM
> >
> It's a problem in the wiring that tends to cause a hum in the radios.
>

ROFL

john smith
July 23rd 03, 02:29 AM
Mike wrote:
> I've read the term ground loop in a lot of articles and accident reports but
> what exactly is a ground loop?

Go to AvWeb.
Under COLUMNS, select the index for John Deakins columns.
Look for the article on Edwards AFB Flight Testing.
Deakins gave instruction in a T-6 Texan (the original) to test pilot
candidates.
At the end of the lesson, he describes how he set them up for a ground
loop.

john price
July 23rd 03, 02:52 AM
Somebody answered in here somewhere that the inside wing
would try to hit the ground because the outside wing would
be generating more lift... Normally, the centrifical force tends
to tip the plane to the outside of the loop... I've done 3 so far and
have always pushed the stick to the inside of the loop to try
to keep the outside tip from dragging... So far the technique
has saved the wings....

John Price
CFII/AGI/IGI
http://home.att.net/~jm.price




"Maule Driver" > wrote in message
. com...
> "BTIZ" > wrote in message
> news:g03Ta.12456$Je.2196@fed1read04...
> > also when the "loop" starts, it is normally started by a gust of wind
on
> the
> > tail, or a lifting of a wing, if the feet are not happy, but behind the
> > movement to corral the tail, the tail will come on around, the wing on
the
> > "outside" of the turn will move faster, create more lift, thus lifting
and
> > possibly dragging the inside wing tip on the ground, plus the added side
> > loads on the gear main tend to cause one to fold..
>
> Does the inside or outside wing tend to hit the ground once a ground loop
is
> underway? I've only done them in gliders (on purpose and by accident
> off-field) but that's the result of dragging the (inside) wingtip. My
sense
> is that the outside wing wants to drag the ground after the groundloop
gets
> going. But I just don't know.
>
> > I'd rather land in some cross wind, then none at all, at least then
you'll
> > know where the trouble could be lurking... and forget tail wind
landings..
> > not good at all..
>
> I gotta admit, I've never wished for any xwind!
>
> >You know what you have when it is a tail wind on both ends of the runway?
A
> >thermal at mid field.. plan to land long, get past the tailwind, through
> the
> >thermal and into the headwind.. for a better controlled landing.
>
> I suspect that only a glider guider would be savvy enough to recognize
this
> condition in time to respond!
>
>

G.R. Patterson III
July 23rd 03, 03:23 AM
john price wrote:
>
> I've done 3 so far .....

If I'da known that, I would *never* have let you try that landing during my
BFR!

George Patterson
The optimist feels that we live in the best of all possible worlds. The
pessimist is afraid that he's correct.
James Branch Cavel

Cub Driver
July 23rd 03, 11:09 AM
>I like the rear engine analogy. Difference between the Beetle and the
>Corvair seems to have been that the Beetle didn't suffer from 'ground
>loops' very frequently. The Corvair was looking for them. My father owned

I live in New Hampshire, where it not only snows, but often rains on
top of the snow. I followed two gal skiers in a VW one time on the
road down from the mountains, and they began to oscillate,
overcorrect, and finally end up in the snowbank on the wrong side of
the road. I dug them out with the shovel I always carried in the front
trunk of my VW. Then, going around an extended traffic circle in
Alton, I too went off the road that same night. A plow truck pulled me
out.

>3 or 4 of them. In #3, we did the classic Corvair 'ground loop' plus some.
>I'm not sure to this day how many times we went around but I do know we
>ended up upside down on the convertible roof. Unsafe at any speed indeed!

Driving home from Vermont in a friend's Corvair, me driving, I could
feel the front end move out from under me about every five minutes. I
was passed three times, and in every case the car that passed me wound
up in an accident a few miles farther along. In that case the Corvair
got home and they didn't, because of that early-warning system of
"black ice" on the road.

>The Vdub bus seems to be immune too. Drove 3 of them in western PA snows
>and never had them try to swap ends. Passed a lot of stuck people too. But
>of course, they were one of the most lethal vehicles on the road. They
>weren't in a lot of accidents, but you stood a good chance of buying it if
>when they were.

Gosh, I had one of those, too. You're right; it never seemed to suffer
from understeer, perhaps because the passenger and the driver were
sitting on top of the front axle! As I recall the shoulder belt didn't
have an inertia reel, and if it was secured you couldn't reach the
instrument panel. So I cut mine off.

My wife and I drove to California and back, sitting out there on the
front axle, with our daughter in a basket between the two seats.
Yikes.

all the best -- Dan Ford
email: www.danford.net/letters.htm#9

see the Warbird's Forum at http://www.danford.net/index.htm
Vietnam | Flying Tigers | Pacific War | Brewster Buffalo | Piper Cub

Cub Driver
July 23rd 03, 11:14 AM
>In the Olden Days, when aircraft didn't have brakes and you just landed
>in any convenient field, groundlooping was how they stopped. In an
>emergency, it may be a better choice than hitting something hard and/or
>expensive.

This is still standard procedure on the ice runway at Alton Bay, New
Hampshire, supposedly the only American airport that is a seaplane
base in the summer and a land airport in the winter.

I'm told that it is also standard procedure to **** on your tires to
freeze them to the ice, chocks not being very useful in that
circumstance. I haven;t tried this myself; first I was too timid, then
the bay didn't freeze, and most recently I couldn't get out of Hampton
for nearly three months because of snow, ice, wind, and mud.

all the best -- Dan Ford
email: www.danford.net/letters.htm#9

see the Warbird's Forum at http://www.danford.net/index.htm
Vietnam | Flying Tigers | Pacific War | Brewster Buffalo | Piper Cub

Ryan Ferguson
July 23rd 03, 03:17 PM
Be careful, though. In some low-legged airplanes lowering the aileron just puts
the airfoil even closer to the ground. In my Pitts Special (assuming no
crosswind correction) it was best to keep the stick neutral if the rear end got
really loose. Never did ground loop it, although god knows I must have come
close a few times.

-Ryan
CFI/MEI/CFI-H

john price wrote:

> Somebody answered in here somewhere that the inside wing
> would try to hit the ground because the outside wing would
> be generating more lift... Normally, the centrifical force tends
> to tip the plane to the outside of the loop... I've done 3 so far and
> have always pushed the stick to the inside of the loop to try
> to keep the outside tip from dragging... So far the technique
> has saved the wings....
>
> John Price
> CFII/AGI/IGI
> http://home.att.net/~jm.price
>
> "Maule Driver" > wrote in message
> . com...
> > "BTIZ" > wrote in message
> > news:g03Ta.12456$Je.2196@fed1read04...
> > > also when the "loop" starts, it is normally started by a gust of wind
> on
> > the
> > > tail, or a lifting of a wing, if the feet are not happy, but behind the
> > > movement to corral the tail, the tail will come on around, the wing on
> the
> > > "outside" of the turn will move faster, create more lift, thus lifting
> and
> > > possibly dragging the inside wing tip on the ground, plus the added side
> > > loads on the gear main tend to cause one to fold..
> >
> > Does the inside or outside wing tend to hit the ground once a ground loop
> is
> > underway? I've only done them in gliders (on purpose and by accident
> > off-field) but that's the result of dragging the (inside) wingtip. My
> sense
> > is that the outside wing wants to drag the ground after the groundloop
> gets
> > going. But I just don't know.
> >
> > > I'd rather land in some cross wind, then none at all, at least then
> you'll
> > > know where the trouble could be lurking... and forget tail wind
> landings..
> > > not good at all..
> >
> > I gotta admit, I've never wished for any xwind!
> >
> > >You know what you have when it is a tail wind on both ends of the runway?
> A
> > >thermal at mid field.. plan to land long, get past the tailwind, through
> > the
> > >thermal and into the headwind.. for a better controlled landing.
> >
> > I suspect that only a glider guider would be savvy enough to recognize
> this
> > condition in time to respond!
> >
> >

john smith
July 23rd 03, 04:38 PM
Cub Driver wrote:
> I'm told that it is also standard procedure to **** on your tires to
> freeze them to the ice, chocks not being very useful in that
> circumstance. I haven;t tried this myself; first I was too timid, then
> the bay didn't freeze, and most recently I couldn't get out of Hampton
> for nearly three months because of snow, ice, wind, and mud.

Hmmm... brings a whole new meaning to the saying "old pilots and bold
pilots". ;-)

Maule Driver
July 23rd 03, 06:22 PM
Is there a connection between VDubs, Cubs, and Maules?

"Cub Driver" > wrote in message
...
<snippety snip>
> Driving home from Vermont in a friend's Corvair, me driving, I could
> feel the front end move out from under me about every five minutes. I
> was passed three times, and in every case the car that passed me wound
> up in an accident a few miles farther along. In that case the Corvair
> got home and they didn't, because of that early-warning system of
> "black ice" on the road.
>
ahhhh, that's what it was, an early warning system. A quick swat to back of
the head would have sufficed.

> Gosh, I had one of those, too. You're right; it never seemed to suffer
> from understeer, perhaps because the passenger and the driver were
> sitting on top of the front axle! As I recall the shoulder belt didn't
> have an inertia reel, and if it was secured you couldn't reach the
> instrument panel. So I cut mine off.

I kind of figured it was non-inertial so that you would be held firmly in
place during a head-on coup de grace. Should have cut it off too.

What did you do for heat? Not much there when new. Less in a couple of
years of salt corrosion. Auxiliary gas heater was great if you added it.
Almost died in mine due to lack of heat but that's another long story.
>
> My wife and I drove to California and back, sitting out there on the
> front axle, with our daughter in a basket between the two seats.
> Yikes.
>
I ripped the seats, installed speakers, curtains, and a big bean bag chair.
I otherwise take the 5th.

We were all young and foolish once.... but sure had fun!

Maule Driver
July 23rd 03, 06:24 PM
.... and in a glider, stuff the stick forward and stay on the brakes to avoid
snapping the tail.

"BTIZ" > wrote in message
news:_dkTa.12831$Je.318@fed1read04...
> the outside wing will hit... with our Pawnee, the inside wing can drag..
and
> then as you "high side" (motorcycle talk) the outside wing can contact the
> ground.. or if you've ever rolled a jeep when you get it side ways..
>

David
July 23rd 03, 10:25 PM
In article >, john smith
> writes

>A ground loop is what happens when a taildragger pilot isn't fast enough
>on the rudder pedals to keep the tail from passing him/her while going
>down the runway.
>Because the center of gravity is behind the main landing gear on a
>taildragger, the tail of the airplane wants to swing around to the
>front.
>The center of gravity is forward of the main gear on a tricycle gear
>airplane, so the nose wants to stay out in front.

It seems to me that this explanation, though common, is oversimplified.
What we are talking about is stability. When an aircraft (or a car for
that matter) turns on the ground a sideways force is developed on the
wheels. There is also a force generated by the sideways acceleration at
the cg and, also, in the case of the aircraft, a side aerodynamic force.
If the combined reaction of the first two is behind the cg than the yaw
motion on the ground will be unstable and may or may not be able to be
controlled by the pilot with the rudder.

It is not that the main wheels are in front of the cg so much as that
the side force developed by the tail wheel is very small (even smaller
if it is a castoring tail wheel) and too much of the side ground force
will be developed by the 'main' wheels.

You only need to be fast on the rudder because the position is unstable.
--
-----------------------------------------------------------
David Francis E-Mail reply to >
-----------------------------------------------------------

Darrell
July 23rd 03, 10:43 PM
Mike wrote:
> I've read the term ground loop in a lot of articles and accident
> reports but what exactly is a ground loop?
>
> --Mike

A ground loop is when the airplanes skids around 360 degrees while
continuing to move in the original direction on the ground.


--

Darrell R. Schmidt

B-58 Hustler History: http://members.cox.net/dschmidt1/

Robert Coffey
July 24th 03, 12:55 PM
BTIZ wrote:
> and that's why tail dragger pilots have "happy feet"..
>
> never heard of a nose wheel aircraft "ground looping", the CG location
> relative to the main gear kinda help keep it straight..

My first solo in a pa28 came real close when I landed in wake turbulance.

Julian Scarfe
July 26th 03, 11:00 AM
"David" > wrote in message
...

> It seems to me that this explanation, though common, is oversimplified.
> What we are talking about is stability. When an aircraft (or a car for
> that matter) turns on the ground a sideways force is developed on the
> wheels. There is also a force generated by the sideways acceleration at
> the cg and, also, in the case of the aircraft, a side aerodynamic force.
> If the combined reaction of the first two is behind the cg than the yaw
> motion on the ground will be unstable and may or may not be able to be
> controlled by the pilot with the rudder.
>
> It is not that the main wheels are in front of the cg so much as that
> the side force developed by the tail wheel is very small (even smaller
> if it is a castoring tail wheel) and too much of the side ground force
> will be developed by the 'main' wheels.

I'm not sure that's the case, David.

The problem with a decelerating taildragger is that the inertial force at
the CG associated with the deceleration occurs behind the retarding force of
the mainwheels on the runway. This is unstable. If the two forces get out
of line, the couple tends to increase. By contrast, having the retarding
force on the main wheels behind the CG is stable.

^
| direction of motion in landing roll.

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

Tricycle:

^
|
* CG

+ wheels
|
v

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

Conventional (tailwheel):

+ wheels
|
v

^
|
* CG

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

Look at the stability to a yaw.

Of course the lateral forces you mention are usually available to control
the situation, which is why the instability isn't manifested as a ground
loop every time. If the aircraft starts to yaw it just gets more draggy,
hence the situation just gets worse.

In principle a tricycle gear aircraft should be susceptible to groundlooping
on take-off, but you have the stabilising advantage of increased drag
hampering acceleration as the aircraft starts to get out of shape.

Julian Scarfe

David
July 27th 03, 01:51 AM
In article >, Julian
Scarfe > writes
>I'm not sure that's the case, David.
>
>The problem with a decelerating taildragger is that the inertial force at
>the CG associated with the deceleration occurs behind the retarding force of
>the mainwheels on the runway. This is unstable. If the two forces get out
>of line, the couple tends to increase. By contrast, having the retarding
>force on the main wheels behind the CG is stable.

Thanks for the comments Julian. My first thought about your suggestions
is that as long as the braking force is directly in the line of
deceleration then there is not a problem but as soon as a yaw develops
then side forces immediately come into play, if they didn't then the
aircraft would not start to turn. It must be very similar to the
oversteer/understeer problem of cars.

In a car if you brake hard and the front wheels lock then the car tends
to go straight on because the yaw stability is still provided by the
rear tyres. If the rear wheels lock up then you will have great
difficulty in stopping a spin. This corresponds to the lack of 'lift'
developed by the tail wheel (particularly if it castors) meaning there
is insufficient yaw stability.

The couple that you mentioned that depends on the retarding force of the
front wheels only produces an effect if a yaw develops. The correction
of the yaw has to be provided by an inbuilt stability or by the rapid
response of the pilot trying, with a big rudder, to introduce
'artificial' stability into the loop.

It has some small similarities to the concept that a high wing aircraft
is more stable because the cg is below the wing. It is more stable but
not due to 'pendulum' stability but due to the way the air flows during
a yaw.
--
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David Francis E-Mail reply to >
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Grandpa B.
July 30th 03, 06:19 PM
I'm in the process of a restorating a '58 Champion 7FC/EC that was
groundlooped in Reno, shortly after being converted to a raildragger. As my
neighbor - from whom I purchased the project - said, they converted it just
in time to groundloop it.

It suffered a great deal of harm: broken wing spars, both main gear
partially torn off, along with the fittings, prop curled back (one blade), a
few bent ribs, scuffed and bent sheetmetal - cowl, etc. The lift struts made
it through, as did the bulk of the airframe.

I'm basically rebuilding it from the tires up - airframe has been faithfully
converted to an EC by removing all vestiges of nosewheel paraphernalia,
blasted and powdercoated, new interior, including floorboards. Even the seat
frames got new powdercoating! I'm in the wiring stage, waiting for the radio
trays to be repaired - not from crash damage, just abuse - then I'll finish
the (brand new) panel wiring and plumbing. Covering isn't far off... Then it
will look like an airplane, rather than a skeleton, in the garage. After
that, it's on to tearing the engine down for inspection.

Jon B.
> wrote in message
om...
> "Mike" > wrote in message
>...
> > I've read the term ground loop in a lot of articles and accident reports
but
> > what exactly is a ground loop?
> >
> > --Mike
>
> Mike,
> If you ever experience a ground loop, you will know it!!!!!
> A ground loop will make a bigger impression on you if you happen to be
> in the back seat of a tandem tail dragger that you own when the wild
> swing happens.
> I let some yahoo fly my 7ac Champ from the front seat because he was
> interested in buying it.....never again.....we ended up in the weeds
> at the side of the runway. Luckly there was no damage and he bought
> the airplane AND I was a LOT SMARTER.
>
> Ken Black

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