The Cold War threatened the world with nuclear annihilation.
Amidst intensifying stress, the Soviet Union dealt with an espionage nightmare that might cost them the atomic race.
The Soviets required a clandestine technique to carry 25-ton nuclear global ballistic rockets throughout their sprawling landscapes without leaving the faintest path for their American adversaries to find.Their solution was absolutely nothing except spectacular.
Enter the Mil Mi-12, a colossal gizmo with the size of an airliner fused with the adaptability of an airlift helicopter.When unveiled at the Paris Air Convention in 1971, it stunned the world; there had never been anything like it.
The alarm bells called in the US as strategists tried to unveil the function of such a staggering machineThe Mil V-12 (NATO reporting name: Homer), provided the task number Izdeliye 65 (Item 65), is a prototype helicopter created in the Soviet Union and the biggest helicopter ever constructed.
The classification Mi-12 would have been the designation for the production helicopter and did not apply to V-12 prototypes.Design and DevelopmentDesign studies for a huge helicopter were started at the Mil OKB in 1959, getting main sanction in 1961 by the GKAT (Gosudarstvenny Komitet po Aviatsionnoy Tekhnike State Committee on Aircraft Technology) instructing Mil Moscow Helicopter Plant to establish a helicopter efficient in raising 20 to 25 tonnes (22 to 28 short heaps).
The GKAT directive was followed by a more in-depth specification for the V-12 with hold measurements similar to the Antonov An-22, intended to lift significant items of combat product as well as 8K67, 8K75 and 8K82 inter-continental ballistic missiles (ICBM).
Design restrictions required Mil to adopt a twin rotor system however design studies of a tandem design, similar to the Boeing CH-47 Chinook, exposed significant issues.
The single rotor designs likewise studied, showed to be non-viable, causing the transverse design selected for the finished article.The transverse rotor system of the V-12, which gets rid of the requirement for a tail rotor, includes 2 Mil Mi-6 transmission systems total with rotors installed at the tips of the roughly 30 m (100 feet) period inverted tapered wings.
Although the first usage by Mil, the transverse system had actually been utilized by numerous of the early helicopters, consisting of the Focke-Wulf Fw 61, Focke-Achgelis Fa 223 Drache and Kamov Ka-22 Vintokryl convertiplane.Construction of the V-12 initially model, after exhaustive testing with test-rigs and mock-ups including a complete transmission system, began at Panki in 1965.
The airframe was mostly traditional, using stressed out skin building techniques with high strength parts machined from strong metal blocks.
The large fuselage accommodated the 28.15 m 4.4 m 4.4 m (92 ft 4 in 14 feet 5 in 14 feet 5 in) cabin and team area in the extreme nose, housing a pilot, co-pilot, flight engineer and electrical engineer in the lower cockpit, with the navigator and radio operator in the upper cockpit.At the aft end of the fuselage access to the cabin is gotten by large clamshell doors and a drop down cargo ramp with inbuilt retractable assistance jacks.
Doors in the fuselage also admit to the freight hold: 2 on the starboard side and 3 on the port side.
Above the rear fuselage is a very large fin and rudder, with a reasonably sized tailplane with dihedral fitted with end-plate fins (not fitted for the first flight).
The repaired undercarriage consists of large paired main-wheel systems on oleo-pneumatic levered shock absorbers installed at the junction of a strut system supporting the rotor systems and wings and linked to the centre fuselage by a tripod strut structure with the nose-leg connected aft of the crew area.
A set of bumper wheels are mounted at the back of the fuselage keel and fixed support pads guarantee that the freight ramp is extended to the appropriate angle.
Long braced struts likewise connected the transmission systems to the rear fuselage forward of the fin.
Freight handling is done by methods of a forklift or electric hoists on taking a trip beams.The power system and wings are mounted above the centre fuselage with interconnecting shafts making sure synchronisation of the primary rotors which overlap by about 3 m (10 ft).
Drag and raise losses are minimized by the inverse taper wings with minimum chord in areas of greatest down-wash.
The adjoining shafts likewise made sure in proportion lift circulation in the event of an engine failure.
To optimise control in roll and yaw the rotors are organized to kip down opposite directions with the port rotor turning anti-clockwise and the starboard rotor turning clockwise, ensuring that the advancing blades pass over the fuselage.Each power system consists of 2 Soloviev D-25VF turbo-shaft engines mounted listed below the main gearboxes which each drive five-bladed 35 m (115 feet) diameter rotors and their synchronisation shafts which run from wing-tip to wing-tip.
Each paired engine pod has big gain access to panels which open for maintenance gain access to and also form platforms for servicing teams to operate from.Aeroflot Mil V-12 (Mi-12) at Groningen Airport.
It was ron its way to the Le Bourget airshow.
Due to the fact that they were not allowed to fly over West Germany (Cold War issues), they needed to re-route by means of Denmark and also The Netherlands to handle fuel.
Currently, this airframe is protected at the Air Force museum in Monino, Russia.Control of the V-12 presented numerous problems to the designers and engineers due to the large size as well as the rotor layout.
The pilot and co-pilot beinged in the lower flight deck with a broad stretch of windows to provide outstanding presence.
Using traditional cyclic stick, cumulative lever and rudder pedals the pilots input their commands in a conventional style.
Roll control is by differential cumulative pitch modification on the left and right rotors, making sure that sufficient lift is produced to prevent unintended sink.
Yaw in the hover or low air speeds is attained by tilting the rotor discs forward and backwards differentially depending on instructions of yaw required.
At higher air speeds differential rotor control is gradually supplanted by the large aerodynamic rudder on the fin.
Climb and descent are managed by the cumulative lever increasing or reducing the pitch of both rotors all at once.
Large elevators on the tailplane assistance control the fuselage mindset and supply reaction to pitching moments from the wing and variation on rotor disc angle.The control system is complex due to the large size of the airplane and the requirement to make up for aeroelastic contortion of the structure, as well as the huge friction loads of the control rods, levers etc.
To keep the control forces felt by the pilots to a minimum, the control system has 3 unique stages.
Phase one is the direct mechanical control from pilot input forces which are fed into a 2nd phase, intermediate powered control system with low-powered hydraulic boosters moving commands to phase three, the high-powered quick action control actuators at the primary transmissions running the swashplates directly.Top Photo: Mil V-12 prototypeSources: YouTube; Wikipedia