Introduction. Fuselage/Cockpit

Transcription

1 Introduction The Moravan Zlin 242L is a fully aerobatic 2 seat aircraft designed to perform all advanced flight maneuvers within an envelope of -3.5 to +6 Gs. Many military and civilian flight-training programs use the 242L for basic and advanced aerobatic training. The aircraft is composed of an all-metal structure, providing easy access to its internals for both academic and maintenance purposes. Side-by-side seating allows for efficient instructor-student interaction, and a full glass canopy allows for full panoramic visibility, which is paramount in aerobatic circumstances. The 242L s sharp yet tame flight characteristics make it a pristine aerobatic aircraft. Fuselage/Cockpit Ideally, an aircraft s body should be light as well as strong. The Zlin s fuselage skeleton is very rigid, composed of steel-tube ribs covered with semi-composite material. This material provides the high strength-to-weight ratio desired for a high performance aircraft. The ribs are covered with light, highstrength sheets of metal alloy. Longitudinal space is saved using a side-by-side seating arrangement as opposed to a tandem arrangement. The cockpit is considered relatively spacious, yet is also concise enough to Longitudinal: lengthwise direction, or front to back provide easy pilot access to fight controls and instrumentation. Bucket-style seats along with a five-point harness keep the occupants tightly secured during violent maneuvers. A back-strap parachute system secured to the occupants throughout the flight caters to safety and comfort. Finally, the forward-sliding canopy promotes uninhibited entering and exiting of the cockpit.

2 Basic Aircraft Parts Wings The wings of the Zlin are composed of aluminum alloyplated sheets. A thick main spar runs the lateral length of the wing structure, providing stability. The ailerons and flaps of the aircraft are made of the same material as the main spar: a wing s primary internal structural member that runs from the fuselage to the wingtip. wings themselves. Composite (high-strength plastic) wingtips come standard on the aircraft, reducing drag and increasing maneuverability. The ailerons are weight-balanced, which is one of several features contributing to the slick responsiveness during control input. The counterweights allow the aircraft to fly true to any control input (or lack of control input) by inhibiting the effects of natural airflow on the control surfaces. The aircraft s wings house both the main and auxiliary fuel tanks. The main tanks are located within the body of the wings along the leading edges. Each main tank holds 16 gallons of fuel. The auxiliary fuel reserves are located within the wing tips, each holding 14.5 gallons of fuel. Tail The tail surfaces of the Zlin are similar in construction to the wings, using thin aluminum alloy-plated metal sheets. As with the ailerons of the aircraft, the elevator and rudder are weight-balanced, providing in-flight stability. Both the elevator and rudder are equipped with trim tabs. Trim tabs are small lift-surfaces attached to the trailing edge of an airfoil (the elevator and rudder, in this case) that can be adjusted by the pilot to regulate a neutral or otherwise desired, flight path of the plane. In other words, trim tabs allow for permanent control input.

3 Flight Controls The Zlin 242L, like a majority of personal aircraft today, is equipped with dual controls. Both pilot and co-pilot have access to a stick-type pitch and roll control, as well as rudder pedals for yaw control. A lever located on the floorboard between the seats controls the flaps. The elevator trim tab control is also located here, behind the flap lever. Perhaps one of the most unique characteristics of the Zlin 242L is the dual throttle control. By common practice, it is customary (assuming a right-handed pilot) to fly the aircraft with the right hand, while controlling throttle input with the left hand. To accommodate this, there is a throttle control rod projecting straight out of the instrument panel housing on the left side for the left-seat pilot. For the right-seat pilot, the main throttle control is located in the center of the instrument panel. Cockpit View: instrument panel, flight controls, throttle controls Also unique to the Zlin242L is the tie-rod-integrated control system. The control surfaces of the aircraft, i.e. the ailerons, elevator and rudder, are directly connected to the flight controls by long metal rods. This type of connection promotes the aircraft s immediate responsive action with control inputs. Such a characteristic is necessary for aerobatic maneuvering. This feature is common in most aerobatic aircraft, yet is not typical in standard general aviation aircraft. Many non-aerobatic personal aircraft utilize a cable-and-pulley-control system, allowing a tamed responsiveness for passenger comfort. Powerplant The Zlin 242L is powered by a Textron Lycoming engine, delivering 200 horsepower at 2700 RPM. The 200 horsepower engine officially places the Zlin 242L in the high performance category. This Textron Lycoming engine allows the Zlin 242L to reach a maximum level speed of 127 knots, or 146 mph when loaded under aerobatic conditions. Powered by the Textron Lycoming engine is the Zlin s three-blade constant speed propeller. Front View: propeller, engine cowling Performance The Zlin 242L is rated for both normal and aerobatic categories. The difference in categories is a function of specified loading of the aircraft. Because of this, the manufacturer publishes performance data for both categories. In this description, only aerobatic category performance will be evaluated.

4 The 200 horsepower engine along with the physical dimensions of the aircraft, govern its performance capabilities. Maximum level speed, as discussed earlier, is 127 knots. Typical cruise power settings are 65% and 75%. The Zlin 242L s cruse performance at 65% power is 100 knots, and at 75% power it moves up to 113 knots. With the flaps set to the takeoff position, the aircraft requires 689 feet of ground roll distance. With full flaps, the aircraft requires 805 feet of ground roll distance for landing. Typical cruising ranges, as tested, are between 230 and 260 nautical miles. The Zlin 242L has a service ceiling of 15,700 feet (typical range for non-pressurized aircraft). 1 knot = 1.15 mph 1 nautical mile = 1.15 miles Summary The simple construction and sharp flight characteristics of the Zlin 242L make it the most widely distributed aerobatic trainer in the world. Over 60 countries have adopted the Zlin for various purposes including military training and personal use. Compared to many other aerobatic aircraft, the Zlin 242L is very affordable, with a price that hovers around $100,000. Smooth operating attitude allows for basic as well as advanced aerobatic maneuvering with unrivaled ease and exceptional comfort.

5 Photo Credits: Overhead Shot: Basic Aircraft Parts: Tail: David Lednicer / Airliners.net Flight Controls: Rob Wall / Airliners.net Powerplant: Diana Matusik / Airliners.net Underbelly Shot: