Wing "Eaglet" - an aircraft with unique properties. Its creation from the moment the idea was born until the forced cessation of work is one of the little-known because of the secrecy, but very interesting pages of the history of technology.
Why did the ekranoplans appear?
The development of technology is primarily a struggle for speed. It is fueled by competition, often fierce, and forces designers to look for new, sometimes unexpected solutions.
Speed, one of the most important qualities of water transport, was limited by insufficient engine power and hydrodynamic resistance of the hull, which increased with increasing speed. And if the first problem was solved using more powerful engines, then you could get rid of the second only by leaving the water. So there were gliders, hovercraft, then hydrofoils, and finally ekranoplanes. It was not for nothing that the designer of the ekranoplan Eaglet was R. E. Alekseev, the famous Soviet hydrofoil designer.
In order for the aircraft to be able to move at high speed on the border of two media - water and air - it was necessary to solve many technical problems.
Firstly, it was necessary to ensure their stability when flying at very low, up to two meters, altitudes. Secondly, the task was to simultaneously ensure the low weight of the structure and its strength when it hits a wave crest at a speed of up to 400 km / h.
Thirdly, it was necessary to find materials that were light and resistant to the effects of sea water, while traditional shipbuilding materials were heavy and aviation materials quickly corroded. The fourth serious task was the creation of light, but powerful engines that are not afraid of splashing salty sea water.
The ekranoplan "Orlyonok" became an aircraft in which the design idea embodied the solution of these and other, no less serious problems.
WIG Installation Series
An aircraft with a screen effect (air flow is thrown down by the wing, is reflected from the surface of water or land and hits the wing, thereby increasing the lifting force) was designed for the navy as an airborne transport vehicle.
From the idea to the first model, the journey was long - more than ten years.
The first flight tests began in 1972 on the Volga. Then, the landing ekranoplan Eaglet was transported to the Caspian Sea, where flights over the sea continued. Tests have confirmed the remarkable flight performance of the new product.
The first two samples were intended for testing and after them were sent for scrap, and one after the accident. Three ekranoplanes with serial numbers S-21, S-25 and S-26, built in 1977, 1980 and 1983, were included in the 11th separate air group, directly reporting to the Main Headquarters of Naval Aviation, and were decommissioned in 2007.
There should have been much more such aircraft; it was planned to build another 120 cars. Then their number dropped to 24, and after the change of leadership of the Ministry of Defense, the program was completely closed.
In the summer of 2007, from the base in Kaspiysk, the best-preserved ekranoplane with serial number S-26 was delivered to Moscow, it became an exhibit at the Navy Museum, and later ended up in a private museum on the Khimki Reservoir.
WIG Design and Purpose
The "Eaglet" is capable of deploying two hundred armed marines or two amphibious armored vehicles (tanks, infantry fighting vehicles, armored personnel carriers) with crews up to one and a half thousand kilometers at a speed of up to 500 km / h. At the same time, the A-90 “Orlyonok” ekranoplan is capable of taking off at a wave height of up to two meters, without losing stability, and to overcome airborne (mine and network) obstacles by air.
The main tactical and technical characteristics include a flight height above the screen from half a meter to ten meters, with a maximum flight height of 3000 m. The maximum take-off weight is 140 tons, 20 of which are cargo.
The overall length is 58.1 m, the height with a propeller in the parking lot is 16 m, the wingspan is 31.5 m, its area is 304 sq. M, the dimensions of the cargo compartment are 21 × 3.2 × 3 m.
A special power connector allows you to swing to the right the bow of the hull with the cockpit. A ramp is advanced, along which personnel and equipment are quickly landing.
"Eaglet" is a low wing with three engines, a fuselage-boat and tail in the form of the letter "T". The main construction material is an alloy of aluminum and magnesium AMG61. Radiolucent surfaces are made of composite materials. Special coatings and electrochemical protectors protect against corrosion.
Wing fuselage and landing gear
In the fuselage with a beam-stringer power structure there is a cockpit and a crew lounge (commander, co-pilot, navigator, mechanic, radio operator, gunner, two technicians), compartments with electronic and radio communication equipment, a compartment for auxiliary power units and other airborne units, a cargo compartment compartment with mooring units.
There is an emergency hatch in the roof of the cockpit, and crew doors on the sides of the hull above the wing.
On the bottom of the boat a system of longitudinal and transverse redans was made, one is attached to it in the bow, and a second ski is located in the area of the center of mass.
The chassis consists of a ten-wheeled main and two-wheeled nose support. In the retracted position, the chassis is partially covered by hydro-skis. The chassis design, ski-shock absorbing device and blowing allow the ekranoplane to move on any soil, ice and snow.
Wing and tail
For lifting a heavy machine above the surface of the water, not only the wing span is important, but also its aerodynamic layout with a large angle of attack, low elongation and sweep of 15 °. The floats at the ends play the role of planing and aerodynamic washers. Aileron flaps and launch flaps change their position during take-off so that jet gas jets from the starting engines fall under the wing, cannot escape from it, and due to their increased pressure, the Eaglet winged aircraft rises from the water.
The tail unit is designed to improve the stability and controllability characteristics of the ekranoplan. A large stabilizer with four-section elevators ensures a stable flight. On the vertical tail, which is a single unit with the fuselage, a marching engine is installed, in which at this height water splashes do not fall during takeoff and landing.
Power point
To provide performance characteristics, in particular, cruising speed, the main power plant consists of three engines: a marching turboprop, whose power is 15 thousand hp, and two starting turbofan engines.
Starting engines have a limited service life, turn on only during take-off, their rotary nozzles allow you to direct gas jets under the wing during take-off, and to horizontal thrust when accelerating to cruising speed. Their air intakes give the bow a peculiar look: they are in front of the cockpit lantern again, so that they do not get splashes of water. To start the starting engines, the auxiliary power unit EA-6A is used.
The main engine drives four-blade pulling propellers. Their diameter is six meters.
Armament and equipment
WIG "Eaglet" is equipped with a navigation system "Screen" with a surveillance radar; automatic flight control system; hydraulic system for steering surfaces drive, wing mechanization, operation of hydro-skis and chassis, rotation of the reclining part of the fuselage; electrical system for powering flight and navigation, radio communications and electrical equipment.
Marine navigation lights and anchor-towing accessories as on any ship.
The main armament of the ekranoplan is the twin cliff machine gun "Cliff" with a caliber of 12.7 mm, which is installed in a rotating turret.
Advantages of ekranoplan "Eaglet"
If we compare with a plane a comparable payload and take-off weight, then the fuel consumption of the ekranoplan is significantly lower, if possible for a long time to fly at high altitude. Another aspect of the economic efficiency of Orlyonok is that it does not need expensive large airfields, for which vast territories are being withdrawn from land use.
For military purposes, the advantage over aircraft is radar stealth at low altitude.
Compared to hydrofoil vessels, the ekranoplan has a much smaller crew, and cruising speed is many times greater.
Safety and amphibiousness, for which the landing winged wing "Orlyonok" was actually intended, provide landing with significant unrest in the sea, as well as in shallow water and ice, on the ground of any complexity.
Maneuverability, long range, separation from the shielding surface at low speed, significant carrying capacity and resistance to combat damage complement the range of unique capabilities of the vehicle.
Yes, the project was unique, and he had great opportunities, but ... dreams did not come true.
What is to blame for it, the cost of the Eagle winged ekranoplane (at the end of the last century the amount of three hundred million rubles was announced to bring the new model to flight condition), too high load-bearing capacity for state programs or the lack of modern materials and equipment, only even in peaceful life unclaimed, despite interesting developments based on it.