What is a ground loop?

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

--Mike

"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

"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

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.

A ground loop is an inadvertant maneuver that allows you to visits parts of
the airport that you never knew existed before...

"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.

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

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

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...

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