Jaworski WJ 3

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Jaworski WJ 3
WJ-3.png
RolePrimary glider
National origin Poland
Manufacturer LOPP Gliding Circle, Stolpce
DesignerWictor Jaworski
First flightEarly 1936
Number built1

The Jaworski WJ 3 was a Polish, low cost primary glider first flown in 1936. It did not prove popular and only one was built.

Glider (sailplane) type of glider aircraft used in the sport of gliding

A glider or sailplane is a type of glider aircraft used in the leisure activity and sport of gliding. This unpowered aircraft can use naturally occurring currents of rising air in the atmosphere to gain altitude. Sailplanes are aerodynamically streamlined and so can fly a significant distance forward for a small decrease in altitude.

Contents

Design and development

The Jaworski WJ 3 was a Polish primary glider designed in 1935 and first flown the following year. It was a single seat, open frame (uncovered flat girder fuselage), wooden aircraft, designed to keep costs to a minimum by using the cheapest construction materials and, with no welded joints, to be within the capabilities of basic workshops. [1]

It had an undivided wing of rectangular plan mounted on top of the fuselage and built around a single spar, which was the rear part of a torsion-resistant, plywood-covered D box forming the leading edge of the wing. Behind the spar the wing was fabric-covered. A single strut on each side braced the spar to the lower fuselage. Rectangular ailerons reached out to the wing tips. [1]

Spar (aeronautics) Main structural member of the wing of an aircraft

In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles to the fuselage. The spar carries flight loads and the weight of the wings while on the ground. Other structural and forming members such as ribs may be attached to the spar or spars, with stressed skin construction also sharing the loads where it is used. There may be more than one spar in a wing or none at all. However, where a single spar carries the majority of the forces on it, it is known as the main spar.

Plywood manufactured wood panel made from thin sheets of wood veneer

Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured boards which includes medium-density fibreboard (MDF) and particle board (chipboard).

Leading edge

The leading edge is the part of the wing that first contacts the air; alternatively it is the foremost edge of an airfoil section. The first is an aerodynamic definition, the second a structural one. As an example of the distinction, during a tailslide, from an aerodynamic point of view, the trailing edge becomes the leading edge and vice versa but from a structural point of view the leading edge remains unchanged.

The fuselage was a modified Warren truss, with a curved lower chord or longeron and two additional, near vertical cross-members under the wing. The WJ 3's pilot sat without back support against the foremost of these on an exposed seat mounted on an extension of the lower longeron that also carried the controls. An unsprung, wooden landing skid was attached underneath. [1]

Warren truss type of engineering truss

A Warren truss or equilateral truss is a type of engineering truss.

Truss structure that consists of two-force members only

A truss is an assembly of beams or other elements that creates a rigid structure. In engineering, a truss is a structure that "consists of two-force members only, where the members are organized so that the assemblage as a whole behaves as a single object". A "two-force member" is a structural component where force is applied to only two points. Although this rigorous definition allows the members to have any shape connected in any stable configuration, trusses typically comprise five or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes.

Another vertical cross-member formed the rudder-post, reaching above the fuselage. Fabric from this to the nearest diagonal cross-member formed a fin between the longerons. Its near-rectanglar rudder was generous and fabric-covered. A narrow, roughly rectangular tailplane was mounted on the upper longeron and strut braced to the lower one. It carried an elevator with two tetragonal, fabric-covered surfaces mounted on a common axle, allowing rudder movement between them. [1]

Rudder Control surface for fluid-dynamic steering in the yaw axis

A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other conveyance that moves through a fluid medium. On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane. A rudder operates by redirecting the fluid past the hull (watercraft) or fuselage, thus imparting a turning or yawing motion to the craft. In basic form, a rudder is a flat plane or sheet of material attached with hinges to the craft's stern, tail, or after end. Often rudders are shaped so as to minimize hydrodynamic or aerodynamic drag. On simple watercraft, a tiller—essentially, a stick or pole acting as a lever arm—may be attached to the top of the rudder to allow it to be turned by a helmsman. In larger vessels, cables, pushrods, or hydraulics may be used to link rudders to steering wheels. In typical aircraft, the rudder is operated by pedals via mechanical linkages or hydraulics.

Fin flight control surface

A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fins are also used to increase surface areas for heat transfer purposes, or simply as ornamentation.

Tailplane small lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyroplanes

A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyroplanes. Not all fixed-wing aircraft have tailplanes. Canards, tailless and flying wing aircraft have no separate tailplane, while in V-tail aircraft the vertical stabiliser, rudder, and the tail-plane and elevator are combined to form two diagonal surfaces in a V layout.

Despite the W.J.6's low cost, build-simplicity, low weight, which allowed easy ground transport, and decent handling in flight trials only one was built.

Specifications

Data from J. Cynk, 1971 [1]

General characteristics

Performance

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References

  1. 1 2 3 4 5 Cynk, Jerzy (1971). Polish Aircraft 1893-1939 . London: Putnam Publishing. p. 733-4. ISBN   0 370 00085 4.
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