Conventional landing gear

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A Cessna 150 converted to taildragger configuration by installation of an aftermarket modification kit Cessna150taildraggerC-GOCB02.jpg
A Cessna 150 converted to taildragger configuration by installation of an aftermarket modification kit

Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail. [1] [2] The term taildragger is also used, although some claim it should apply only to those aircraft with a tailskid rather than a wheel. [2] [3]

Contents

The term "conventional" persists for historical reasons, but all modern jet aircraft and most modern propeller aircraft use tricycle gear.

History

Tailwheel detail on a Tiger Moth biplane De Havilland DH.82 Tiger Moth - undercarriage tailwheel detail.jpg
Tailwheel detail on a Tiger Moth biplane
Like many attack helicopters, the AgustaWestland Apache has a tailwheel to allow an unobstructed arc of fire for the gun. AgustaWestland Apache AH1 10 (5968018661).jpg
Like many attack helicopters, the AgustaWestland Apache has a tailwheel to allow an unobstructed arc of fire for the gun.

In early aircraft, a tailskid made of metal or wood was used to support the tail on the ground. In most modern aircraft with conventional landing gear, a small articulated wheel assembly is attached to the rearmost part of the airframe in place of the skid. This wheel may be steered by the pilot through a connection to the rudder pedals, allowing the rudder and tailwheel to move together. [2] [3]

Before aircraft commonly used tailwheels, many aircraft (like a number of First World War Sopwith aircraft, such as the Camel fighter) were equipped with steerable tailskids, which operate similar to a tailwheel. When the pilot pressed the right rudder pedal — or the right footrest of a "rudder bar" in World War I — the skid pivoted to the right, creating more drag on that side of the plane and causing it to turn to the right. While less effective than a steerable wheel, it gave the pilot some control of the direction the craft was moving while taxiing or beginning the takeoff run, before there was enough airflow over the rudder for it to become effective.

Another form of control, which is less common now than it once was, is to steer using "differential braking", in which the tailwheel is a simple, freely castering mechanism, and the aircraft is steered by applying brakes to one of the mainwheels in order to turn in that direction. This is also used on some tricycle gear aircraft, with the nosewheel being the freely castering wheel instead. Like the steerable tailwheel/skid, it is usually integrated with the rudder pedals on the craft to allow an easy transition between wheeled and aerodynamic control.[ citation needed ]

Advantages

Douglas DC-3, a taildragger airliner Dc3.takeoff.thales.arp.jpg
Douglas DC-3, a taildragger airliner

The tailwheel configuration offers several advantages over the tricycle landing gear arrangement, which make tailwheel aircraft less expensive to manufacture and maintain. [2]

Disadvantages

A replica World War 1 F.E.2 fighter. This aircraft uses a tailskid. The small wheel at the front is a safety device intended to prevent nose-over accidents FE2B, Masterton, New Zealand, 25 April 2009 05.jpg
A replica World War 1 F.E.2 fighter. This aircraft uses a tailskid. The small wheel at the front is a safety device intended to prevent nose-over accidents

The conventional landing gear arrangement has disadvantages compared to nosewheel aircraft. [2]

A parked Vought F4U Corsair. If this aircraft were taxiing, the pilot would be unable to see the photographer F4U-4 Bu97388 front view.jpg
A parked Vought F4U Corsair. If this aircraft were taxiing, the pilot would be unable to see the photographer

Jet-powered tailwheel aircraft

Royal Navy Supermarine Attacker landing at RNAS Stretton, England, 1956 Supermarine Attcker FB.2 WP290 ST812 1831 Sqn STN 25.02.56 edited-2.jpg
Royal Navy Supermarine Attacker landing at RNAS Stretton, England, 1956

Jet aircraft generally cannot use conventional landing gear, as this orients the engines at a high angle, causing their jet blast to bounce off the ground and back into the air, preventing the elevators from functioning properly. This problem occurred with the third, or "V3" prototype of the German Messerschmitt Me 262 jet fighter. [5] After the first four prototype Me 262 V-series airframes were built with retracting tailwheel gear, the fifth prototype was fitted with fixed tricycle landing gear for trials, with the sixth prototype onwards getting fully retracting tricycle gear. A number of other experimental and prototype jet aircraft had conventional landing gear, including the first successful jet, the Heinkel He 178, and a single Vickers VC.1 Viking, which was modified with Rolls Royce Nene engines to become the world's first jet airliner.

The sole surviving Yak-15. Vadim Zadorozhny Technical Museum, Moscow, 2012 Yakolev Yak-15 '37 yellow' (38910149232).jpg
The sole surviving Yak-15. Vadim Zadorozhny Technical Museum, Moscow, 2012

Rare examples of jet-powered tailwheel aircraft that went into production and saw service include the British Supermarine Attacker naval fighter and the Soviet Yakovlev Yak-15. Both first flew in 1946 and owed their configurations to being developments of earlier propeller powered aircraft. The Attacker 's tailwheel configuration was a result of it using the Supermarine Spiteful's wing, avoiding expensive design modification or retooling. The engine exhaust was behind the elevator and tailwheel, reducing problems. The Yak-15 was based on the Yakovlev Yak-3 propeller fighter. Its engine was mounted under the forward fuselage. Despite its unusual configuration, the Yak-15 was easy to fly. Although a fighter, it was mainly used to prepare Soviet pilots for flying more advanced jet fighters.

Monowheel undercarriage

A Schleicher ASG 29 glider shows its monowheel landing gear Alexander Schleicher ASG 29.JPG
A Schleicher ASG 29 glider shows its monowheel landing gear

A variation of the taildragger layout is the monowheel landing gear.

To minimize drag, many modern gliders have a single wheel, retractable or fixed, centered under the fuselage, which is referred to as monowheel gear or monowheel landing gear. Monowheel gear is also used on some powered aircraft, where drag reduction is a priority, such as the Europa XS. Both monowheel gliders and monowheel power aircraft use retractable wingtip legs (with small castor wheels attached) to prevent the wingtips from striking the ground. A monowheel aircraft may have a tailwheel (like the Europa) or a nosewheel (like the illustrated Schleicher glider).

Training

Taildragger aircraft require more training time for student pilots to master. This was a large factor in the 1950s switch by most manufacturers to nosewheel-equipped trainers, and for many years nosewheel aircraft have been more popular than taildraggers. As a result, most Private Pilot Licence (PPL) pilots now learn to fly in tricycle gear aircraft (e.g. Cessna 172 or Piper Cherokee) and only later transition to taildraggers. [2]

Techniques

Landing a conventional geared aircraft can be accomplished in two ways. [6]

Normal landings are done by touching all three wheels down at the same time in a three-point landing. This method does allow the shortest landing distance but can be difficult to carry out in crosswinds, [6] as rudder control may be reduced severely before the tailwheel can become effective.[ citation needed ]

The alternative is the wheel landing. This requires the pilot to land the aircraft on the mainwheels while maintaining the tailwheel in the air with elevator to keep the angle of attack low. Once the aircraft has slowed to a speed that can ensure control will not be lost, but above the speed at which rudder effectiveness is lost, then the tailwheel is lowered to the ground. [6]

Examples

Examples of tailwheel aircraft include:

Airplanes

Helicopters

Modifications of tricycle gear aircraft

Several aftermarket modification companies offer kits to convert many popular nose-wheel equipped aircraft to conventional landing gear. Aircraft for which kits are available include:

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References

Citations

  1. 1 2 Crane, Dale: Dictionary of Aeronautical Terms, third edition, page 133. Aviation Supplies & Academics, 1997. ISBN   1-56027-287-2
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 From the Ground Up, 27th edition, page 11
  3. 1 2 Brandon, John. "Recreational Aircraft Australia - Groundschool". Archived from the original on 2008-07-19. Retrieved 2008-12-05.
  4. Scott, Jeff. "Aerospace Web - Aircraft Landing Gear Layouts" . Retrieved 2016-02-19.
  5. Boyne 2008, p. 60.
  6. 1 2 3 Transport Canada, Aeroplane Flight Training Manual, page 111 (4th revised edition) ISBN   0-7715-5115-0

Bibliography