IIL IS-5

Last updated
IS-5
Role Single seat high performance Sailplane
National origin Romania
ManufacturerIntreprinderea de industrie Locală (IIL)
Designer Iosif Șilimon
First flight 14 June 1960
Developed from URMV-3 IS-3

The IIL IS-5 was a single seat, high performance sailplane designed by Iosif Șilimon and built in Romania in 1960.

Iosif Șilimon was a Romanian aircraft designer.

Romania Sovereign state in Europe

Romania is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders the Black Sea to the southeast, Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, and Moldova to the east. It has a predominantly temperate-continental climate. With a total area of 238,397 square kilometres (92,046 sq mi), Romania is the 12th largest country and also the 7th most populous member state of the European Union, having almost 20 million inhabitants. Its capital and largest city is Bucharest, and other major urban areas include Cluj-Napoca, Timișoara, Iași, Constanța, Craiova, and Brașov.

Contents

Design and development

From about 1950 to his death in February 1981, Iosif Silimon was Romania's most prominent glider designer, his aircraft distinguished by his initials. [1] The IS-5 first flew on 14 June 1960. It was a shoulder wing cantilever monoplane developed from the URMV-3 IS-3 and of mixed wood and metal construction. The wings had an all wood structure and were plywood skinned. Mounted with 3° of dihedral, they were straight tapered in plan and built around a single spar with a forward torsion box between it and the leading edge. The tips carried the small streamlined bodies known as salmons, common at the time. The slotted ailerons, which filled about half the span, were ply skinned but with an outer fabric covering. [2]

Cantilever beam anchored at only one end

A cantilever is a rigid structural element, such as a beam or a plate, anchored at one end to a support from which it protrudes; this connection could also be perpendicular to a flat, vertical surface such as a wall. Cantilevers can also be constructed with trusses or slabs. When subjected to a structural load, the cantilever carries the load to the support where it is forced against by a moment and shear stress.

Monoplane Fixed-wing aircraft with a single main wing plane

A monoplane is a fixed-wing aircraft with a single main wing plane, in contrast to a biplane or other multiplane, each of which has multiple planes.

The IS-3 was the basis of a family of high performance gliders designed by Iosif Şilimon and built in Romania in the 1950s at the URMV-3 factory at Braşov.

The IS-5's pod and boom style fuselage was a metal monocoque with the pod ending abruptly at the wing trailing edge and a slender boom aft. The cockpit was enclosed by a single piece, side hinged, moulded perspex canopy. Rectangular airbrakes hinged outwards from the fuselage sides under the wing, each with an area of 0.325 m2 (3.5 sq ft). The empennage was conventional, with a ply covered fin which was narrow at the top but faired into the boom above and below. It carried a fabric covered, rounded, unbalanced rudder, broad at its heel, as well as the straight edged tailplane placed just above the boom. There were rounded, spring balanced elevators with gaps at their roots to clear the fin and a small cut out for rudder movement; these control surfaces were ply skinned and fabric covered like the ailerons.

Fuselage aircraft main body which is the primary carrier of crew, passengers, and payload

The fuselage is an aircraft's main body section. It holds crew, passengers, and cargo. In single-engine aircraft it will usually contain an engine, as well, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage, which in turn is used as a floating hull. The fuselage also serves to position control and stabilization surfaces in specific relationships to lifting surfaces, which is required for aircraft stability and maneuverability.

Monocoque Structural design that supports loads through an objects external skin

Monocoque, also structural skin, is a structural system where loads are supported through an object's external skin, similar to an egg shell. The word monocoque is a French term for "single shell" or "single hull". First used in boats, a true monocoque carries both tensile and compressive forces within the skin and can be recognised by the absence of a load-carrying internal frame.

Trailing edge

The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge rejoins. Essential flight control surfaces are attached here to control the direction of the departing air flow, and exert a controlling force on the aircraft. Such control surfaces include ailerons on the wings for roll control, elevators on the tailplane controlling pitch, and the rudder on the fin controlling yaw. Elevators and ailerons may be combined as elevons on tailless aircraft.

The IS-5 had a short, rubber sprung skid under the cockpit and a fixed, unsprung monowheel under the wing, fitted with a brake. There was also a small extension of the fin to act as a tail bumper. [2]

Specifications

Data from The World's Sailplanes (1963), pp.194-5 [2]

General characteristics

Airfoil

An airfoil or aerofoil is the cross-sectional shape of a wing, blade, or sail.

NACA airfoil

The NACA airfoils are airfoil shapes for aircraft wings developed by the National Advisory Committee for Aeronautics (NACA). The shape of the NACA airfoils is described using a series of digits following the word "NACA". The parameters in the numerical code can be entered into equations to precisely generate the cross-section of the airfoil and calculate its properties.

Performance

  • Stall speed: 55 km/h (34 mph; 30 kn)
  • Never exceed speed: 180 km/h (112 mph; 97 kn) placard, smooth air
  • Rough air speed max: 150 km/h (93 mph; 81 kn)
  • Aerotow speed: 120 km/h (75 mph; 65 kn)
  • Winch launch speed: 90 km/h (56 mph; 49 kn)
  • Maximum glide ratio: best, 28:1 at 78 km/h (48 mph; 42 kn)
  • Rate of sink: 0.74 m/s (146 ft/min) minimum, at 64 km/h (40 mph; 35 kn)
  • Wing loading: 20.9 kg/m2 (4.3 lb/sq ft)


Related Research Articles

Slingsby Skylark 3

The Slingsby T.43 Skylark 3 was a single seat Open Class sailplane developed from the Skylark 2 with an extended wingspan. It gained first place at the 1960 World Gliding Championships.

Slingsby Skylark 4

The Slingsby T.50 Skylark 4 was a British single seat competition glider built by Slingsby Sailplanes in the early 1960s. It sold in numbers and had success at national, though not world level competition.

I.S.T. XL-15 Tagak

The I.S.T. XL-15 Tagak was a single-engine, twin-boom, high-wing monoplane designed after the I.S.T. XL-14 Maya and built in the Philippines in the mid-1950s. The result of a collaboration between a Government research institute and the Philippine Air Force, it was designed as a utility, liaison or ambulance aircraft and as a test bed for the use of local materials in aviation.

The Akafleig Darmstadt D-34 sailplanes were a series of experimental single seat sailplanes, designed at the University of Darmstadt in the 1950s and early 1960s to explore the structural and aerodynamic advantages of the then emerging plastics and composite materials.

CVV 8 Bonaventura

The CVV 8 Bonaventura was a two-seat competition glider designed and built in Italy during the 1950s. Fifteen were produced.

The UTG-1 Loudon was an intermediate glider designed and built at the University of Toronto in Canada during the late 1940s.

Not to be confused with the IS-4 Jastrząb from Instytut Szybownictwa in Poland.

The CVT1 Zigilo was a single-seat, 12 m (39 ft) span Italian training glider designed and built in Italy in the 1950s. Only one was completed.

CVT2 Veltro

The CVT2 Veltro was an Italian competition glider built in the mid-1950s. Its advanced design incorporated a laminar flow wing, T-tail, retracting undercarriage and a reclining seat to reduce parasitic drag.

The IIL IS-4 was a single seat, high performance sailplane designed by Iosif Șilimon and built in Romania in the late 1950s.

The IIL IS-7 was a two-seat, sailplane designed by Iosif Șilimon and built in Romania in the late 1950s. Only one prototype was built.

The IIL IS-8 was a two seat sailplane designed by Iosif Șilimon and built in Romania in 1960. They served with Romanian gliding clubs.

The IIL IS-9 was a low powered, experimental pod and boom style motor glider, designed and built in Romania in the late 1950s.

The IIL IS-10 was a high-performance, single-seat glider, designed and built in Romania in the early 1960s. It was the first Romanian aircraft to use laminar flow airfoils.

The IIL IS-11 was an aerobatic, single seat glider, designed and built in Romania in 1959. It was built in small numbers.

The IIL IS-12 was a two seat glider, designed and built in Romania in 1960. It had a wooden wing but a metal fuselage and was constructed in parallel with the all-wood IS-13 for comparative tests. It was later followed by the IS-13a, a version with an all-metal wing.

The IFIL-Reghin RG-5 Pescăruș or CIL Reghin RG-5 Pescăruș was a Romanian single seat sailplane built in the 1950s. Twenty six were constructed for gliding clubs.

The Merville SM.31 is a French high performance glider with a laminar flow wing, first flown in 1960. Only one was built.

The Jancsó-Szokolay M22 was a Hungarian single-seat sailplane first flown in 1937. Twenty were built and the type set several national records. Some remained in service up to about 1953.

References

  1. ↑ Taylor, John W. R. (1981). Jane's All the World's Aircraft 1981-1982. London: Jane's Information Group. p. 586. ISBN   0710607059.
  2. 1 2 3 Shenstone, B.S.; Wilkinson, K.G. (1963). The World's Sailplanes. II. Organisation Scientifique et Technique Internationale du Vol à Voile (OSTIV) and Schweizer Aero-Revue. pp. 194–5.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.