Energy Technologies

Sikorsky 300

1939 – 1945

Igor Sikorsky (1889 – 1972) Russian/American develops and flies first successful helicopter in the United States.

Sikorsky hires Glidden S. Doman (Glid) to address helicopter structural and dynamic problems including blade failures in the first Sikorsky R-4 helicopters. Whilst testing and adjusting all subsequent Sikorsky R-4 helicopters before delivery for use in WWII, Glid Doman discovers the causes of vibrations, high stresses, and failures in the helicopter rotor systems.

1945 – 1947

Glidden S. Doman (1921 – 2016) an American aeronautical engineer and pioneer in helicopters and modern wind turbines founds one of America’s original six helicopter companies, Doman Helicopters, Inc.. 

The Bell 47 becomes the first helicopter certified for civilian use. It is two bladed and features a teeter hinge and more than 5.000 Bell 47 aircrafts are produced. The first Doman version of the R-6 helicopter, with the four-bladed Doman rotor flies in 1947.

1948 – 1969

NASA appoints Gild Doman to a committee to investigate helicopter blade failures and fractures.

The Doman/Curtis-Wright CW-40, a 400-horsepower prototype with Doman’s unique rotor design, flies for the first time in 1949. The Doman LZ-5, with improvements on the CW-40, first flies on April 27, 1953. This LZ-5 rotor, the next generation Doman design, includes the novel gimballed rotor to eliminate major forces and stresses, incorporate speed reduction gearing, and contains all moving parts within a common housing to preclude damage from weather or foreign matter. The LZ-5 receives its FAA type certificate on December 31, 1955. Two LZ-5 helicopters are delivered to the US Army by Doman in the attempt to develop commercial sales. He later negotiates production rights with Hiller Aviation, Avions Marcel and SAI Ambrosini. In 1960, the LZ-5 flies in the Paris Air Show.

The company was dissolved in 1969.

1970 – 1974

In 1970, Glid Doman goes to work for Boeing’s helicopter division in Philadelphia where, in 1973, he adapts helicopter simulation models to study wind turbines. Scale model wind turbines are tested in a wind tunnel normally used for helicopters and airplanes. He soon recognised the similarities and key differences between wind turbines and helicopters. Specifically, he identifies that since a wind turbine is analogous to a hovering helicopter (i.e. it does not engage a forward flight), the Bell-Helicopter-style two-bladed rotor with teeter hinge is the optimum way to eliminate stresses in wind turbines. Thus, the thoroughly proven teeter hinge is imported from helicopters and becomes a standard component in American large wind turbine research projects. (A teeter hinge cannot be used with a three-bladed, or more, rotor).

In 1974, NASA’s Glenn Research Center in Cleveland, Ohio initiates and leads a 7 year U.S. wind energy program for the development of utility-scale horizontal axis wind turbines, which results in the Boeing MOD-2 with the Doman-conceived flexible design, two-bladed wind turbine with a teeter-hinge.

1978 – 1982

The Swedish government requests Hamilton Standard (a United Technologies Company) to hire Gild Doman to initiate the WTS-3 project – a 3 MW, two-bladed, teeter hinge wind turbine, for installation in Maglarp, Sweden.

Under Doman’s leadership as System Design Manager, Hamilton Standard’s 4 MW, WTS-4 turbine begins operating in Medicine Bow, Wyoming and goes on to hold the world power output record for over 20 years. This is the same two-bladed, teeter hinge design as the WTS-3 with a larger generator. To this day the WTS-4 remains the most powerful turbine ever to have operated in the United States.


Aerospace pioneer, Kurt Hohenemser declares that a helicopter-type rotor is more suitable for wind turbines than commonly used propeller-type rotors. Glid Doman, who was separately developing the concept of using yaw power control in a turbine, recognises that teeter hinge technology can eliminate the complex and costly pitch control system and Kurt Hohenemser endorses Doman’s wind turbine design.

1987 – 1992

In 1987, the Italian government hires Glid Doman to head Italy’s Gamma head wind turbine project. Enel (Italy’s largest utility) and Aeritalia buy a license from United Technologies to design and demonstrate the new Gamma technology in Sardinia under Wind Energy Systems Taranto SpA (WEST).

The Gamma 60 begins operations in Alta Nurra, Sardinia, Italy in 1992. This 1.5 MW HAWT introduces novel industry features, including broad range variable speed, fixed pitch and yaw power control. Doman’s flexible two-bladed turbine design, supported by teeter hinge technology, enables the Gamma 60 to be lighter and longer lived than its competitors.

1997 – 2003

In 1997, Silvestro Caruso, assigned by Finmeccanica for independent design review of the Gamma 60 wind turbine, concludes that the Gamma technology has great potential.

Three Gamma 60 turbines were manufactured, and one was erected and successfully tested for four years on the Mediterranean island of Sardinia. There were intentions to build many  more Gamma 60 turbines, but political challenges and a lack of urgency due to low oil prices in the 1990s resulted in the program being cancelled.

In 2003, Glid Doman, Silvestro Caruso, and other shareholders establish Gamma Ventures, Inc. to buy two unused Gamma turbines, the engineering drawings, in addition to the manufacturing rights from the Gamma 60 project owners.

2004 – 2007

Martin Jakubowski establishes Blue H Technology Ltd to develop floating offshore wind turbines in 2004. Sky Saver srl, the Italian subsidiary of Blue H Group Technology Ltd, files for a grant and permission to install a two-bladed wind turbine on a floating foundation (TLP type) off the Straight of Otranto, in the Southern Adriatic Sea.

Martin Jakubowski and Silvestro Caruso meet for the first time in 2006.  The decision was reached that the Gamma 60 is the best solution for offshore wind energy applications and that further development of the technology should occur within Blue H Group Technology Ltd (“Blue H”) so Gamma Ventures sell a turbine and manufacturing rights to Blue H.

In 2007, Martin Jakubowski & Silvestro Caruso, during their tenure within Blue H, install the world’s first floating wind turbine off the coast of Tricase, Italy in a water depth of 113 meters.


In 2009, the New England Air Museum acquire a Doman LZ-5 helicopter for public display.

Blue H obtained a grant from the Energy Technologies Institute, a public-private partnership between global energy and engineering companies, and the UK Government, to design a 5 MW floating wind turbine on a TLP support structure, using the two-bladed teeter hinge and the other key Gamma 60 technical features developed by Doman.

2010 – 2014

In 2010, Blue H shareholders decline funding for additional development of the two-bladed turbine. Martin Jakubowski and Silvestro Caruso, with support from Gamma Ventures, Inc., establish Condor Wind Energy Ltd after acquiring all relevant assets from Blue H to further develop its proprietary two-bladed teeter hinge offshore wind energy technology. 

Condor Wind Energy Ltd operations decline after internal differences in 2014.

2014 – 2017

In 2014, Martin Jakubowski and Silvestro Caruso create Seawind Ocean Technology B.V. in the Netherlands. Seawind Ocean Technology signed an agreement, in 2015, to buy back all assets of Condor Wind Energy Ltd., including most importantly, all technological and intellectual property.

All shareholders of Gamma Ventures Ltd became shareholders of Seawind Ocean Technology Holding B.V in 2017.


Seawind Ocean Technology Ltd was created in the UK to develop a British legal entity to support the growing offshore wind industry in UK waters.

Seawind Ocean Technology’s turbines receive ‘Technology Qualification’ status from DNV GL. An accelerated schedule to full certification was agreed with DNV GL resulting in Type A achievement in 2023 (Seawind 6) and 2024 (Seawind 12).

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