Feature

The Mil Mi 26 Halo - a scientific marvel 25 years on

 Garth Cambray

The worlds largest flying helicopter is the Mil Mi 26. One of these great flying machines was recently in action in South Africa, lifting 20 ton payloads of logs off a stricken ship which ran aground near Birha in the Eastern Cape. Garth Cambray rushed out to the coast with barely contained glee with Jim Cambray in tow to capture the magic of this machine in pictures.

Mil Mi 26. Photo Jim Cambray

As the proud pilot of the giant craft told me, 'it is built by the great people of Russia'. With the cold war over, machines once designed primarily for military use have now been sent out to quiet retirements as civilian vehicles. In Africa, the Mil Mi 26 series of helicopters are helping limit environmental damage through assisting in salvage operations by lifting dangerous cargos off stricken ships. The helicopters are also being used to log forests in a far more sustainable fashion, as lifting giant hardwood logs straight out of a forest limits the need for building roads and also limits the impact on undergrowth allowing for sustainable cropping.

In this edition of Science in Africa we will first look at the history and engineering behind this, the greatest of all flying helicopters.

A Brief History of Helicopters

The first helicopter like toys were made by the Chinese in about 400 BC. Slowly over the centuries many innovators were fascinated by the idea of a helicopter like machine, with minds such as Leonardo da Vinci and many others toying with designs. It was in 1863 that Viscount Gustave de Ponton d'Amécourt coined the word helicopter based on a fusion of the Greek words heli (spiral) and copter (wing). All the pioneers to this point were however limited by the fact that no power source existed which could supply abundant power without being abundantly heavy at the same time. The invention of the internal combustion engine changed this and the pace of helicopter evolution picked up in the early 1900s.

Many helicopter designs were developed - frequently seriously impeded by the fact that a rotor turning in one direction will cause the larger object below it to rotate in the other direction. Coaxial designs using two sets of rotors helped overcome this problem. In 1924 Etienne Oehmichen flew the first circular flight with a distance of 1km. In 1936 the Focke Wulf Fw 61, the first practical helicopter was produced. Three years later one of the great names of helicopter history, Igor Sikorsky, developed the first practical single rotor helicopter, which was later put into production. Many great strides were made in helicopter technology during the Second World War. Much of the technology developed in Germany influenced the design of helicopters around the world later. During this time, the problem of the helicopter rotating in the opposite direction to its rotors was solved by placing a small vertical rotor on an extended tail. This rotor could counteract the tendency of the helicopter to spin.

Mil Helicopters

In 1947 Mikhail Mil entered the story of the helicopter story in a meaningful way. A truly inspiring man, his influence on the helicopter world has been such that currently a quarter of all helicopters flying are of Mil design. The factory which he founded is one of the largest helicopter factories in the world and is a world leader in terms of technology.

Heavy Lift Helicopters

The Mil Mi26T "Halo' hovering as it lowers a cross shaped load of logs exhibits its halo for all to see. Photo Jim Cambray

Starting in 1954 various heavy lift helicopters were designed, tested and in some cases produced by the Mil factory. The Mil 6 Hook was for many years the most successful heavy lift helicopter. With a maximum speed of 300km/h and a lifting capacity of 15 tons, more than 860 of these machines were manufactured up until 1981.

In 1968 the Mil 12 Homer made history as the world's largest helicopter. With a maximum capable weight of 105 tons this was truly a monstrous helicopter. In 1969 one of these helicopters lifted 40.2 tons to 2225m above sea level. They were however a bit thirsty as far as fuel was concerned due to their 4 giant 4125 kilowatt motors, and never reached production.

In 1981 the Mil Mi 26 Halo replaced the Mil Mi 6 as the Mil production heavy lift helicopter. This venerable helicopter remains, to this day, as the single largest operational production helicopter.

With a lifting capacity of 20 000kg, the giant is powered by two very quiet and very impressive 8550 kilowatt turboshaft engines. To put this in perspective an average family car has a motor with an output of between 70 and 100 kilowatts.

The only helicopter in the world to sport 8 rotors, the Mil Mi 26 T supposedly gives a far smoother rider than other helicopters. Here the 8 rotors, each with an individual length of 16 meters are seen gently swishing by as the machine returns for its next load. Photo Jim Cambray

To picture this helicopter, imagine a machine which is a bit longer than a bus at 33 meters. It has rotors that are 32 meters across and the little tail rotor at 7.61 meters would probably not look out of place atop a small helicopter. If you wanted to foot the bill, you and your friends and at least two good sized cars could park inside it - at US$12 000 an hour.

Another engineering novelty with this helicopter is the fact that it has 8 rotors. The rotors themselves are rather complicated and expensive being made with considerable quantities of titanium. They have de icing systems, to allow flying in hostile environments.

The Mil Mi 26 in action

Startup

The small jet engine below the cockpit, which provides power to the helicopters' avionics even when the main motors are silent, begins operation with roughly the same amount of noise as a small Bell Jetranger helicopter.

Lift-off

A few seconds later the main engines power up and the rotors slowly pick up speed. The petrol tanker which has just pumped 5600l of fuel into the tanks of the helicopter beats a hasty retreat from the dust storm kicked up by the 90km/h 'breeze' which the rotors send towards the ground.

Amid a cloud of dust and with a strong smell of burnt fuel in the air, the Mil Mi26T lifts gently into the blue sky. Photo Jim Cambray

Flying

The Mil Mi26T carrying a giant pump capable of emptying an Olympic pool in an hour manages to make its 4 ton load look rather insignificant. Nevertheless, few other helicopters could carry this 'small' load. Photo Jim Cambray

Slowly, gracefully the machine lifts off the ground rising like a dragonfly to a height of 100m after which the pilot gently nudges it away. The giant helicopter makes less noise as it glides away than a small two person helicopter nearby.

The Mil Mi 26 comes in many forms ranging from military troop carriers to flying small hospitals and even to a flying fuel tanker with 10 fuel hoses. It lands, vehicles line up and they get their fuel. In fire fighting and general logistics these vehicles have proved invaluable, as invaluable as they are in logging and in this case, in salvage operations.

Well, as the pilot said, this machine is built by the Great People of Russia. A firm foundation of Science, Engineering and Technology in that country mixed with a good bit of pride has furnished us in Africa with an ideal tool to solve certain logistical problems.

More information:

In the next edition of Science in Africa we will explore how these helicopters are used in the exciting, and potentially lucrative field of marine salvage, and, in the next, at the application of the helicopters in sustainable logging operations.

Science in Africa - Africa's First On-Line Science Magazine

Copyright  2002, Science in Africa, Science magazine for Africa CC. All Rights Reserved

Terms and Conditions