Ground Looping

[Deskpilot]

OK, I'll start the ball rolling. What is the main cause of ground looping?

 

 

[Thruster88]

OK, I'll start the ball rolling. What is the main cause of ground looping?

 

The main causes of ground looping are,  Note, there may be more than one correct answer.

 

(A) The CoG is ahead of the main gear

 

(B) The pilot fails to apply rudder correction in a timely manner 

 

© The CoG is behind the main gear

 

(D) A gust of wind strikes the aircraft at an inconvenient time

 

 

[kasper]

OK, I'll start the ball rolling. What is the main cause of ground looping?

 

Ground loop vs loss of control

 

1. Only tailwheel aircraft ground loop.  Nose/tri gear aircraft lose control and have wing strike/tip over.  

 

2. Ground loops are where the cofg behind the main gear swinging around in a turn on the ground exceeds the capacity of the airframe/pilot to provide turning force to bring the nose back around.

 

classic / common causes

 

1. Exceeding the crosswind capabilities of the airframe/pilot. 

 

2. Not holding the tail down on rollout and getting a gust. 

 

3. Low time thruster pilots raising the tail too early on takeoff and having P force combine with gust then cut power to recover... you will loop beautifully. 

 

no.3 deserves a row of chairs popcorn and score cards.  Single seater t85 with r503 is the best at doing this to you.  

 

 

[Deskpilot]

 "Single seater t85 with r503 is the best at doing this to you. "  OH Shit. Just my luck.

 

[facthunter]

  Any  tailwheel plane is basically directionally unstable as the wheels are ahead of the CofG and any sideload on the wheels will make it want to turn. The more sideload the greater the force and tendency to turn more  rapidly. The only way to counteract it is with rudder and sometimes differential braking  but the braking must be done cautiously. Early correction is best and know the factors involved with it occurring. Gyroscopic precession as the tail is raised. Engine anti torque reaction, and swirling airflow onto one side of the rudder/fin.  Cross winds, dragging brake from bad feet position or adjustment high grass or mud drag on one wheel, Flat tyre Propeller "P" factor if taking off tail low on a short field .

 

     It's done on purpose in a glider or a plane if it's going into a wire fence to prevent your head being severed by the wire. In that case do it into wind as it may not work the other way . Nev

 

 

[djpacro]

Plus: it is less unstable with more download on the tailwheel giving the tyre extra friction so it definitely helps to put the stick in the correct position.

 

Of the two airplanes I usually fly: Super Decathlon with just the pilot in the front seat I can easily pick the tail up however  with the Pitts S-2C I cannot budge it myself, let alone with the pilot in the rear seat. Still, the Pitts gets twitchy halfway through the landing roll.

 

 

[facthunter]

Tail down means wheels further forward of the Cof G. Some planes need the T/W on the ground  firmly to steer  especially with a downwind and no real propwash. Nev

 

 

[SSCBD]

Being proactive with you feet. Trained a lot of people (with no brakes) and they suddenly learned what rudder pedals do. Specifically if they came from GA.  

 

 

[kasper]

Being proactive with you feet. Trained a lot of people (with no brakes) and they suddenly learned what rudder pedals do. Specifically if they came from GA.  

 

Absolutely agree - train on a thruster and you know what your feet are for and what ground loops are from day 1 ... train on a drifter and you will have less idea (very low ground angle means you can't be very slow and close to stall on touchdown ... you have more rudder authority on touchdown simply due to speed)

 

But GA is different - Citabria is a pussy cat ... never felt like it wanted to loop ... whereas the Auster j/5 I flew seemed to want to bite its own tail until it was engine off and back in the hangar

 

But most GA are so heavy and have brakes and that has meant that when I trained people onto thrusters and even drifters they discovered their feet pretty quick

 

 

[Deskpilot]

Thanks guys, guess it's time for mr to start tap dancing.?

 

 

[turboplanner]

Thanks guys, guess it's time for mr to start tap dancing.?

 

Just make sure you programme the right songs into EFIS.

 

 

[Old Koreelah]

Lessons I learned all by myself: 

 

Taxying with the wind is a great way to find out your rudder works opposite to what you wanted. 

 

Landing with a strong sidewind, you might need a burst of power to keep the tail in line.

 

 

[Admin]

You know guys, you can click any of the arrows on the left of a post...up arrow as you favourite answer or down arrow as your least favourite answer...similar to the Likes system but as a voting system which helps the user asking the question which is likely to be the best answer and they can then click trophy as their best answer...this is what the the Question forum is all about and helps to provide an education element to flying and goes towards one of the site's objectives

 

 

[Thruster88]

I ground looped my single seat Thruster once when I was relatively inexperienced, it took me by surprise. I was more careful after that.

 

Had another almost moment in front of the crowd at Holbrook fly in early '90s. We had got permission to depart during the air show. In a rush to get away I brought the power up to quickly before I was completely straight on the runway, full opposite rudder and only just held it. It would have been so embarrassing, luckily just a good learning experience about pressure and other distractions.    

 

 

[IBob]

I was one of a DC3 full of jumpers that fishtailed down the runway on takeoff in Rylstone Kandos some years ago. Maybe gyroscopic precession when the tail came up, followed by lazy overcorrecting feet. A nasty sensation......(

 

 

[NT5224]

I've never ground looped yet, but have come close.  The  Rebel is surprisingly merciful  as a tail dragger,  compared to  lighter aircraft such as the Lightwing.  But its  a challenge to respond to cross wind gusts  (or bumpy uneven surfaces) with corrective rudder inputs without over-correcting  and establishing a pattern of increasing oscillations. 

 

Here's my  personal tip (which some will disagree with!).  On take off with a tail dragger I never just shove the throttle full open, because  a sudden  rudder input to correct the centrifugal yaw could establish that oscillation.  Instead I apply power steadily , and introduce the appropriate level of  rudder accordingly as we get going. I can still get off really short doing it this way. 

 

 

[damiens]

Tail down means wheels further forward of the Cof G. Some planes need the T/W on the ground  firmly to steer  especially with a downwind and no real propwash. Nev

 

So facthunter, would it be fair to say that putting larger main wheels on a taildragger would generally make it more stable, once the tailwheel is on the ground?  

 

 

[facthunter]

Quite a few factors involved in that. More  grip, Higher up and greater angle of attack  as it sits, (The tail is more shielded) Usually only racers have very small tail area and must steer with the steerable tail wheel at all but higher speed and/or with power on. No I can't agree with the proposition but it would have to be flight tested to find out. Some POHs don't recommend the use of brakes for directional control where the rudder is effective but obviousl;y they are there for the skilled (or foolish if they aren't skilled) to use Nev

 

 

[Thruster88]

So facthunter, would it be fair to say that putting larger main wheels on a taildragger would generally make it more stable, once the tailwheel is on the ground?  

 

If you put big enough wheels on a Drifter it would sit like a Thruster so definitely less stable according to what I have read here. 

 

 

[kaz3g]

Plus: it is less unstable with more download on the tailwheel giving the tyre extra friction so it definitely helps to put the stick in the correct position.

 

Of the two airplanes I usually fly: Super Decathlon with just the pilot in the front seat I can easily pick the tail up however  with the Pitts S-2C I cannot budge it myself, let alone with the pilot in the rear seat. Still, the Pitts gets twitchy halfway through the landing roll.

 

The Decathlon is surely the C172 of the tailwind types... a real gentle lady. I’ve never flown one but the Pitts is undoubtedly a different beast.

 

 

[440032]

Put all the theories aside, here's how you do it properly:

 

https://www.supercub.org/forum/showthread.php?25435-How-To-Groundloop-Your-Taildragger

 

 

[Geoff_H]

I would not say that tricycle gear cannot ground loop!  Did it when a brake stuck on! Anything will ground loop if the resultant drag forces produce a moment offset from the centre of gravity

 

 

[facthunter]

It's not really a ground loop though. It's a turn all right but it's different in Nature. The cause of the ground loop is SIDE load on the gear which produces a turning couple as the line of the force is ahead of the Cof G. With a stuck brake you have a non symmetrical braking force pulling you back on one side. If you COULD counter it with a good brake  applied equally on the other side  you would balance it out and you still have the nosewheel to steer with Nev

 

 

[Geoff_H]

It certainly went 270degrees.  Yes you could counteract it if you could discover the stuck brake in less than a second.  Took me some time after the craft stopped.  It was kinda frightening.

 

 

[Thruster88]

All Musketeer's (they have a nose wheel)  have this placard on the panel    RAISE FLAPS TO INCREASE BRAKE EFECTIVNESS 

 

It could have said BRAKE EARLY WITH THE FLAPS DOWN FOR AN EXCITING GROND LOOP  it is not unlike a handbrake turn in a car.