How to ground loop your taildragger

[kaz3g]

I pinched this from a very old post on another site but thought you might enjoy a little bit of tongue-in-cheek...Kaz

 

How to groundloop your taildragger

 

Thought as many here fly "conventional gear" aircraft, you would enjoy this wonderful essay, written by 3 time unlimited aerobatic champion Lloyd Beaule:

 

HOW TO GROUNDLOOP YOUR TAILDRAGGER

 

INTRODUCTION

 

Judging by how frequently it is performed, the Groundloop is indeed a popular maneuver. The Groundloop is an extreme low-level figure that is highly aerobatic in nature, which may be executed in many exciting variations. It is customarily performed as the last figure in a sequence, but I have seen the Groundloop attempted as a preliminary or warm-up maneuver.

 

It is rarely scored, however, because it is most often performed out of the Judges line-of-sight. Also, the Ground loop is categorized as a surprise maneuver, and therefore nobody is really prepared when it is executed. In fact, the figure is not considered genuine unless Judges, spectators and the pilot-in-command are all surprised! The many interesting and dynamic variations do not have a Degree of Difficulty or “K” attached, but rather are rated on the International HC* scale.

 

HISTORICAL PERSPECTIVE

 

The Groundloop is one of the earliest recorded aerobatic figures. It was performed on virtually all taildraggers, dating back to Aviation’s infancy. The maneuver really came into its own during the Golden Era of the Groundloop, which was when the cross-wind landing was invented.

 

Previous to this, circular landing fields were the norm, and the pilot simply eye-balled the windsock, and landed into the wind. However, it was soon discovered that a short, straight landing strip could be plowed out, and now there would be lots of room for hangers, clubhouse, and an expansive cocktail lounge. Once everyone saw how much fun this new land-use concept generated, it was adopted internationally. The daily Groundloop displays were an instant hit, and helped cast the new idea in tarmac.

 

ANALYSIS

 

Most Groundloops are weathercocking related phenomena. This means that at least one main wheel must be touching the earth, and a wind is blowing. Traditionally, the maneuver is started in a crosswind; during the landing roll-out the tail is allowed to be blown down-wind. At this point there are a variety of options that can be exercised depending on your inputs, and the maneuvers can take off in almost any direction, and finish in a variety of attitudes. Groundloops that occur under calm conditions are more rare, and require vigorous control inputs, so you really have to work at it to get a decent one.

 

Groundloops can be generated anywhere from 5 MPH to flying speed. When executed at high speed, the figure covers more territory and generally spawns the most interesting variations.

 

*HOLY COW

 

High-wing taildraggers probably Groundloop the best because the upwind wing is more exposed to the breeze. The high-wing also enjoys a longer arm to really accelerate things once the maneuver starts. If the airplane is designed with the wheels forming a small triangle (short-coupled), and in the hands of the right pilot, this could be a Groundlooping champion.

 

ESSENTIAL BACKGROUND KNOWLEDGE

 

Avoid the study of the following subjects:

 

a) Cross-wind Landings and Take-off

 

B) ground handling in winds

 

Avoid seeking instruction on these subjects, for it will greatly reduce your chances of producing a truly World-Class Groundloop. Also, you might want to have a good line ready in case someone raises one of these subjects in conversation: “Cross-wind Landings? Hell, wasn’t that about lesson 5 on your Private License? I’m way beyond that!”

 

PREPARATION

 

To be successful, we must prepare both pilot and aircraft.

 

PILOT

 

To perform good Groundloops, the best preparation is no preparation.

 

AIRCRAFT

 

The aircraft can be prepared in a variety of ways to ensure consistently good Groundloops. First of all, the main wheels should be shimmed to a toe-in condition. If the wheels are adjusted to track straight ahead or are shimmed slightly tow-out, the tracking will be too stable to assist your attempts at groundlooping. Keep the tire pressures different from one another. If you know the direction of the cross-wind, reduce the pressure on the up-wind tire before going flying. And remember, it isn’t necessary to change the tires until you can see the second ply of fabric showing; a blow-out can be the start of a dazzling Groundloop.

 

Avoid the hassle of taking off those troublesome wheel-pants by putting a drop of Loc-tite on the screws. Now you have a good excuse not to inspect the brakes. So, when the brake fails on one side or the caliper pinches through a rusted disc, you will enjoy a splendid Groundloop.

 

At the back end, you can start by loosening the fitting that holds the tail-wheel spring to the fuselage. Just back the nuts off a few turns. Also back off the nut that attaches the tail-wheel casting to the spring. Now, slack off the steering springs a couple of links so the chain sags. And while you’re at is, cut that lock wire that some conscientious Engineer installed in case the chains break. From time to time they break on landing and produce a thrilling, and rakish Krameresque lurch. Fantastic! These simple mods will produce a delightfully loose rear-end that feels like it’s on ball-bearings.

 

The little tail-wheel tire is best left alone; over time it becomes worn into an interesting cone-shape by the effects of slipstream, P-factor and gyroscopic effect. These left-turning forces create more wear on the starboard side of the tire, and soon you have a beautifully unstable little demon back there to really help you out.

 

Install the push-to-talk switch in a remote area of the cockpit. When the tower talks to you on the roll-out, you can look down into the cockpit to locate the button, and when you look up, you may be treated to the wonderful green-and-blue kaleidoscope of rotation about the vertical axis.

 

TECHNIQUE (HOW-TO)

 

Once the pilot and aircraft are prepared, it’s a little like shooting fish is a barrel; there’s really nothing to it. There are several things you can do to get the Groundloop going, but really the best thing to do is nothing. Just let it happen. If you are landing or fast-taxiing in a cross-wind and you want a Groundloop … you guessed it – do nothing.

 

Taxi with abandon. As a pilot, you are a free-spirited individual, and this can be best displayed by a carefree jaunt down the taxiway. Just let go of the stick and use the hands-free time to organize your maps and sequence cards. If the tail-wheel comes off the ground, you’re going a little fast. Maybe you’ll want to use the time to put on your seatbelt, polish the inside of the canopy, re-tie your shoelaces or perhaps light up a smoke.

 

Taildragger have the right-of-way, so you won’t have to stop suddenly. When cleared for take-off, start bringing the power up as you swing out on to the runway. Of course you’ll want to shove the stick forward quickly to get that tail up (you can’t get it up too soon). If the plane will fly at 50, hold it on until 65. This technique spreads out the landing gear and brushes off some rubber, but everybody does it and it looks cool. If you get rolling quickly, any cross-wind won’t matter. Now rotate as you imagine you would in a 767. Haul straight back with controls neutral, and blaze off into the blue.

 

On the approach, keep it low and fast. If the airplane lands at 50, cross the fence at 100. It’s best not to have a planned touchdown point because that can interfere with the free-spirited nature of the flying event. Start fanning the rudders through 500 feet, and keep it going until you’ve cleared the runway. The fanning technique is to let the airplane know who’s boss. Get the plane down to the runway as soon as possible, and force it to land with plenty of forward stick. The fast-landing method is good for all weather conditions, especially quartering tailwinds. Once the plane is firmly on the ground, let go of the stick, but keep fanning the rudder to cool the tail-wheel assembly. Taxi in as you taxi ed out

 

VARIATIONS

 

1. 45-Degree Overland Express

 

This one is best done at about 40 MPH. The airplane is allowed to weathercock slightly, the upwind wing and wheel are allowed to rise about 30 degrees and the plane swings into the wind. At 45 degrees off the runway heading, sharp downwind brake, full aft stick and aileron into the wind are added to stop the Groundloop. The plane is now headed off overland. This is useful for taking a shor-cut to the washrooms after a long flight.

 

2. 90-Degree Quick Turns with Prop Curl.

 

Use the same technique as above, except at about 20 MPH. When you stomp on the downwind brake, also shove the stick forward. Even though you are traveling slower, the gyroscopic effect of shoving the stick forward will give you that extra 45 degrees of rotation. The tail will rise briskly. As soon as the prop touches the runway, pull hard back on the stick and apply both brakes. This was how the original Q-Tip Propeller was invented. If you’ve done it right, you’ll probably have a much more efficient prop.

 

The Prop Curly can also be done straight ahead. Taxi at about 10 MPH while tucking in your shirt or cleaning your sunglasses. Keep your hands off the stick and slam on the brakes. Voila! Also try this while maneuvering the tail-wheel over an obstacle. For a more dramatic Curl, hold the stick forward and add a burst of power.

 

3. Pitts Special Twin Arcs.

 

Start the Groundloop from the roll-out at about 25 MPH. Remove all cross-wind inputs and allow the airplane to weathercock. Move the stick forward to at least neutral to lighten the tail-wheel and reduce its directional control. The little biplane will rise up on the downwind wheel and begin a concise pirouette. The downwind wing-tip will hit the runway and begin scribing an arc of red butyrate, dacron and plywood. Without hesitation, slam in full upwind aileron, as if to attempt to lift the lower wing. The downwind aileron will shoot down and subscribe a beautiful red arc parallel to that made by the wing-tip. Pull the stick full back, push full downwind brake with full rudder and a burst of power to erect the plane. These little red arcs are very artistic and will attract a good crowd in the evening following the day’s flying.

 

4. 180-Degree Pirouette with Back-Track

 

This one is best attempted in a light high-wind with narrow bungee landing gear. A Cub will do. The maneuver works best in a quartering tail-wind. This figure looks difficult, but is really pretty simple. It works best if the pilot does not interfere.

 

Get the weathercocking started in the usual manner. Move aileron out-of-wind and push the stick forward to get weight off the tail. 20 MPH is fine. As the up-wind wing rises, the center of gravity swings as a pendulum toward the lower wing. About the time the down-going wing smacks the runway, the center of gravity will have swung to the outside of the downwind wheel. Apply this brake hard. Now it’s as if you had two upwind wheels because the center of gravity has migrated outside via centrifugal force. So now it wouldn’t matter which brake you applied, the effect would be to increase the rotation of the Groundloop.

 

The wing-tip smacks off the tarmac, the brake accelerates the rotation and the plane has completed a full 180-degree turn, and is now rolling backwards down the runway in the breeze. This is very effective if you forgot something back at the hanger, like your lunch or you glasses; just add a little power and fast-taxi back to the button.

 

5. Groundloop with Bunt

 

This is certainly one of the more dramatic figures in the Groundloop family. You’ll want to be traveling a little faster to get this one. Say 35 MPH. The figure should start slowly, then get faster and tighter as rotation sets in. A dry runway is necessary, and a quartering tail-wind from the left is best. Once rotation starts, shove in full down-wind stick and full-forward elevator. This will really tighten up the rotation. Now add full brakes and full power. The tail will shoot upwards and the airplane will do a kind of shoulder roll right on to its back! This is really low-level inverted, and you should ensure that your belts are very tight. This figure should be reserved for the last flight of the day.

 

CONCLUSION

 

The Groundloop has been around for almost a century and I’m sure it will be with us forever. And to keep it alive, all we have to do is be a little complacent, a little ****-sure and a little in a hurry. Most important, one needs a thorough misunderstanding of weathercocking, cross-wind take-offs, landings and ground-handling. Sounds pretty easy to me.

 

 

[Geoff13]

I will let you know how I go with that Sunday after my lesson in the C140 taildragger.

 

 

[kaz3g]

I will let you know how I go with that Sunday after my lesson in the C140 taildragger.

Hi Geoff

 

Just keep your feet dancing on the pedals...little light jabs each way as you roll out on landing to keep it straight down the runway.

 

The 140 is a lovely little aeroplane and I know you will have a ball getting to know its quirks. One of my mates recently refurbished a 120 but I think he must have done it as a mantel display because he spends all his time in the USA instead of back here flying it!

 

Let's know how it goes, please.

 

Kaz

 

 

[Aldo]

I pinched this from a very old post

Kaz

 

I love it reminds me of my very first outing in a DK8 (Decathlon for those who don't know the aircraft) using the left runway on a parallel runway setup listened to all the pre flight instructions from the instructor (apparently not well enough) light crosswind from the left, gentle power up (not gentle enough) nose forward too early and too fast and before you know it I'm mixing it with the poor guy trying to take off on the right runway (not quite that dramatic but you get my meaning) all good in the end didn't bend the aeroplane got into the air (only because the instructor actually knew his sh1t about 55 at the time) but will never again forget those lessons learnt that day.

 

And for those that don't know a tail dragger isn't landed until it is parked and tied down or in the hanger with the doors shut.

 

Aldo

 

 

[djpacro]

... gentle power up (not gentle enough) nose forward too early and too fast ..

the nose always goes forward at the start of the takeoff roll, at an increasing rateI'll let Dazza deal with the last sentence.

 

 

[djpacro]

the nose always goes forward at the start of the takeoff roll.....

sorry, comes from sitting too much in the front seat playing student with an instructor trainee in the back directing - by the time we have that brief discussion the trainee has discovered one of the principles of flight: flying with an instructor one's IQ drops whereas the IQ of the instructor increases by the same amount.

[IanR]

Have you been out practicing Kaz - maybe a demo at Wentworth would be good ?

 

 

[kaz3g]

Have you been out practicing Kaz - maybe a demo at Wentworth would be good ?

Ian, at my age I have to practice more than most because I forget everything so quickly...you're just a young whippersnapper now but you'll be old one day, too.

 

Yes, I'm planning on being there but don't think I'll camp...oh, maybe.

 

Must be your shout!

 

Kaz

 

 

[IanR]

Ian, at my age I have to practice more than most because I forget everything so quickly...you're just a young whippersnapper now but you'll be old one day, too.Yes, I'm planning on being there but don't think I'll camp...oh, maybe.

 

Must be your shout!

 

Kaz

We are camping at the local Motel !!

 

 

[Marty_d]

Kaz, I was fascinated by these instructions and think it's unfair that this beautiful maneouvre should be limited to taildraggers.

 

Can you please post another set for tricycle aircraft?

 

 

[PommyRick]

I did my Tailwheel endorsement last year and wish I'd converted earlier, it adds a whole new dimension to flying. However, I think I've been close to ground looping on two occasions which I hope are enough to remind me to keep the stick back and the wing down.

 

 

[kaz3g]

Kaz, I was fascinated by these instructions and think it's unfair that this beautiful maneouvre should be limited to taildraggers.Can you please post another set for tricycle aircraft?

Well Marty, it's a funny thing you should say that because I was looking for some sage words to pass on for all those less than intrepid flyers who abuse tricycle undercarriages.

 

It seems they are a shy lot because there aren't many of them that will admit to things gone wrong and why. However...

 

The interesting thing about the tricycle U/C is that it was designed so as to allow pilots with lesser skill sets to survive their otherwise crappy landings. It did this by locating the c of g ahead of the mains and propping up the nose on a third wheel. The further forward the nose wheel, the more the aircraft will remain stable IF LANDED CORRECTLY AND IN A STRAIGHT AHEAD CONDITION. Of course, the further ahead it is the longer the moment arm when you stand on the pedals and the Girlings cause the tyres to cease turning while you slide to what may be an unfortunate crash stop with your nose planted in the altimeter. You can place a lot of strain on that bit of duralumin tube doing this.

 

Landing with too much uncorrected drift or under heavy braking, or on the nosewheel first may cause the aircraft to swerve; it may depart the runway rapidly; or it may even tip over thereby reducing the effective radius of the propellor. Whatever the result, it will certainly be entertaining. There are some amongst us who have witnessed such gyrations from our armchairs strategically located outside the aeroclub bar where we score each pathetic attempt by the students to impress us.

 

Landing heavily on the nosewheel is almost guaranteed to make the aircraft porpoise which, in turn, can result in buckled firewalls or http://www.aviationchatter.com/2011/10/stunning-nose-gear-collapse-caught-on-video/ It's the sort of activity that you really ought tell someone about lest some other poor hapless sod have his weakened appendage fall off at a critical moment.

 

The primary cause of these humorous diversions is, once again, the inability of the pilot to REALLY land his tricycle aeroplane as though it were a taildragger...that is, tail a little low, stalled and on the mains first.

 

Kaz

 

Lest any student, ab initio or with high hours in his/her logbook take offence, I hasten to point out this is my attempt at humour and is not directed at anyone on this list most particularly myself.

 

 

[Marty_d]

Thanks Kaz - to come clean (and I've admitted this already on this site) - I have actually broken off the rear tie-down ring on a C172. It would have been an interesting landing to judge from the strategically located armchairs, however everyone who had an ounce of sense knew that the crosswind was too strong for enjoyable flight and had buggered off home.

 

I had about 20 hours at the time and was 18 years old, which in any endeavour is a dangerous combination. Added to which 3 pax whom I'd agreed to take on a local joyflight in conditions that were marginal at best.

 

Long story short, it all got overwhelming at the point of arrival and I managed to stall the aircraft a few feet above the runway. I remember noticing the main gear flexing way more than I'd ever seen before and we thumped down pretty hard, but the first I knew of any damage was when the CFI rang me the next day to enquire about why the tie-down ring was absent.

 

 

[SDQDI]

I wonder what FW is.

An FW is three models later than the FT. The FW is the more well known of the two except in some online forum communities where the FT is still very active. Both the FT and the apparently 'improved' FW are looked at with disdain by most but as disliked as they are the community just can't seem to be able to get rid of them.

 

 

[djpacro]

Easy to get rid of me.

 

 

[SDQDI]

Easy to get rid of me.

DJ I in no way consider you an FW, for what it's worth I generally enjoy your posts and find them informative. I posted what I posted as an attempt at humour

 

 

[djpacro]

More good advice at http://www.taildraggers.com/Documentation.aspx?page=StickBack (see other pages there too) and http://www.dylanaviation.com/

 

 

[Dick Gower]

sorry, comes from sitting too much in the front seat playing student with an instructor trainee in the back directing - by the time we have that brief discussion the trainee has discovered one of the principles of flight: flying with an instructor one's IQ drops whereas the IQ of the instructor increases by the same amount.

Can I use that Dave or is it copyrighted?

 

 

[djpacro]

Feel free to use it - my observations indicate around 10-20%.

 

 

[facthunter]

Re the links posted by DJP. Very good and should be universal knowledge but isn't . Read all words carefully and imagine you are in the situation described, and work out exactly what is happening. For example don't just say "top rudder good thing to use" without qualifying it (as the writer does).

 

The X-wind T/O is the first detailed description I have read in years. I would suggest one slight modification( If you agree). Having held the plane down a little longer than normal, lift off cleanly and keep a little to a bit of upwind aileron applied, (slight bank into wind) and take off the downwind rudder smoothly and allow the plane to turn into wind, so you track out on centre line. In the first 30 feet or so with a crosswind there WILL be windshear and you don't want the into wind wing to be higher than the other. Once you have the crab angle you desire fly normally. Nev

 

 

[poteroo]

The X-wind T/O is the first detailed description I have read in years. I would suggest one slight modification( If you agree). Having held the plane down a little longer than normal, lift off cleanly and keep a little to a bit of upwind aileron applied, (slight bank into wind) and take off the downwind rudder smoothly and allow the plane to turn into wind, so you track out on centre line. In the first 30 feet or so with a crosswind there WILL be windshear and you don't want the into wind wing to be higher than the other. Once you have the crab angle you desire fly normally. Nev

I'd say that happens anyway. Once you make a clean lift-off, the aircraft immediately turns toward the upwind,(down), wing and by the time you can level the wings - viola, the crab angle has been setup. Exactly how it was instructed to me on a C180 back many moons. happy days,