Rotor Torque

Large Scale Helicopter Use For Atlanta Olympics

The US FAA and helicopter operators are working together to implement a far reaching plan for large scale helicopter operations during the 1996 Atlanta Olympic Games. The joint government and industry project could see as many as 200 helicopters operating over 8000 services during the two week period of the games, with medical, corporate transport, freight express, security and EMS services all operating in an integrated system equipped with GPS for navigation and automatic datalink systems (ADS). ADS would constantly provide air traffic control and security operations with the exact positions of helicopters operating under the system, while also telling pilots the relative positions of other ADS equipped helicopters around them. Helicopters operating under the system would also operate along defined helicopter routes, which may be directed over Atlanta’s freeway system to reduce the numbers of people affected by aircraft noise. VIP and airline helicopters may also be able to operate into railway/subway stations, bus stops and major event sites. The helicopter operating plan has been enthusiastically embraced by the FAA, HAI and helicopter operators, as well as major corporate sponsors, who are realising that during the Olympics it will be difficult to transport guests and executives via surface transport because of expected road congestion.

Ge Engines For Ka-62

Kamov and General Electric have agreed to fit the 16 seat class Ka-62 currently under development with GE CT7 turboshafts. Initially five engines are being supplied to Kamov free of charge from General Electric, which has received a $US1m grant from the US Trade and Development Agency. The GE powered model, the Ka-62M, is intended for export outside the CIS, and aside from the engines, differs from the base Ka-62 in having a five (rather than four) bladed main rotor. The standard domestic Ka-62 meanwhile is powered by RKBM Rybinsk RD-600 turboshafts. The first flight of the Ka-62M is due some time later this year, with series production getting underway in the middle of next year. Planned purchase price for the Ka-62M is about $US4m. Design features of the aircraft include a shrouded tail rotor (unlike other Kamov designs which feature contra rotating rotors) and greater than 50% of airframe structure comprising composites.

Aus Rotor Researcher Wins Award

The DSTO’s Air Operations Division’s Dr Neil Gilbert has won a 1994 Achievement Award for contributions to research under the four nation Technical Cooperation Programme (TTCP). Dr Gilbert was part of a team which developed improved mathematical models to predict the air loads and stresses on helicopter rotors. The team used extensive test measurements from a UK Puma to validate the assumptions of previous analytical models and use the data to make significant improvements. In particular the team developed these models’ abilities to predict the effects of airflow over swept back rotor tips which are commonly used on modern helicopters such as the Sikorsky S-70 series. The new and improved models allow the design of rotor configurations that perform better with reduced fatigue loads while reducing the costs associated with their design and development. Dr Gilbert’s work also means that the DSTO can give better advice on the most appropriate rotor configurations for future ADF helicopters. TTCP is a multi lateral forum through which the UK, USA, Canada, New Zealand and Australia cooperate on a range of defence science and technology research programmes, and is based on the principle that no one nation can afford to meet all of its research and development needs on its own.

Mitsubishi Unveils Rp-1 Twin

Mitsubishi Heavy Industries revealed it is developing a new four tonne, eight passenger class twin engine utility helicopter that would compete with the Dauphin and S-76 among others. The RP-1 was displayed in model form at February’s Japanese International Aerospace Exhibition in Tokyo, design features of which included a shrouded tail rotor, four blade main rotor and two rows of four abreast seating in the main cabin. Although the design has not been firmed, the RP-1 will be powered by a development of the new MG-5 engine Mitsubishi is developing for the Kawasaki OH-X military scout helicopter. If the programme is launched by mid year, the first flight could take place next year, with possible customer deliveries in 1998. Maximum speed would be over 150kt (278km/h), while range would be 460nm (850km). Payload would be two tonnes.

No Comanches, But 60 More Black Hawks

The US Army’s Fiscal 1996 budget proposal includes a request for a final 60 Sikorsky UH-60 Black Hawk helicopters and confirms the cancellation of production of the Sikorsky Boeing RAH-66 Comanche. The US Army, faced with a sharply declining budget, was forced to cancel Comanche production because of a lack of funds. The Army previously described the Comanche as the “quarterback of the battlefield” and would restart the production phase of the programme if more funding is forthcoming. However the Army is continuing to fund construction of two prototypes and the development of the T800 engines and the missile package. The US Army’s funding proposal also includes funding to modify AH-64 Apaches to Longbow Apache configuration and the upgrade of OH-58s to OH-58D Kiowa Warriors.

Study Validates Notar Safety

A study of helicopter accidents and their causes has shown that 68% of all tail rotor mishaps and nearly 14% of all helicopter accidents could have been prevented had the aircraft involved been fitted with McDonnell Douglas’ NOTAR anti torque system. Florida based Advanced Aviation Concepts (a company that specialises in helicopter safety issues and works closely with the FAA and HAI) analysed 359 US single engine helicopter accidents which occurred between 1988 and 1993. The study found that of the 23 fatalities caused by tail rotor accidents, up to 14 could have been prevented had the aircraft been equipped with NOTAR. McDonnell Douglas is also confident that the proven safety of NOTAR helicopters should translate into reduced insurance premiums. According to Hank Johnson of St Louis based Daniel and Henry Insurance the “AAC study offers some very impressive statistics” which “will give brokers an effective tool for negotiating lower insurance rates for NOTAR system equipped helicopters.”

Parallel Computers Used For Helicopter Design

Researchers from SCOREC and the Rensselaer Rotorcraft Technology Centre (RRTC) are jointly developing parallel-platform computer modelling tools for use on IBM’s SP system that will allow aerodynamics engineers to accurately simulate the flight performance of helicopters. The use of computers to design helicopters is not new, however, parallel platform modelling tools as developed by IBM can process vast amounts of data rapidly by dividing tasks across dozens and even hundreds of powerful processors, providing much faster performance than traditional computers. Previously the scope of computational experiments has been severely restricted by a lack of computer processing power. Parallel computers have a unique capacity to translate complex processes and vast amounts of data in real time into more easily understood pictures, video and sound. Complex computer modelling tools will enable aerodynamic engineers to bring computer simulated aerodynamic testing to a much higher level of realism. “Aerodynamics engineers have long recognised the need to address detailed geometry in their calculations but the computing power to perform these studies was not available before parallel computing,” said Dr Bill Jennings of the Rensselaer Rotorcraft Technology Centre.

Sikorsky Tests Variable Diameter Tilt Rotor Model

Sikorsky has begun flight testing development models of its unique Variable Diameter Tilt Rotor (VDTR) concept, the models proving to be very stable in hovering flight. Unlike the conventional tilt rotor system used on the XV-15 and V-22 Osprey, the VDTR concept uses telescopic rotor blades to vary and optimise the rotor’s diameter for different phases of flight. The rotors are at their greatest diameter for vertical takeoff when the great load carrying and autorotation characteristics are greatest, while the blades length would be retracted for forward flight. Another advantage of the VDTR concept compared with conventional tilt rotors is that because of the rotor blades’ reduced length in aircraft mode/forward flight they are not as sensitive to roll/yaw coupling, which reduces the need for a greater tail area, while they are less prone to prop whirl flutter, reducing the need for the wings to be so stiff, and thus saving weight. Sikorsky engineers have been testing one sixth scale models which feature three bladed tilt rotors which have a full diameter of 2.5m. Testing continues and Sikorsky is working on potential problems with the transition from vertical to horizontal flight at low speed, where rotor wake can destabilize the aircraft.

Briefs

Hawker de Havilland Systems Engineering has been selected for the design, trial installation and supply of production kits of an Acoustic Data Recorder System for the RAN’s Seahawks. A HdH team will carry out system development at HMAS Albatross at Nowra. A correction to last month’s column. The caption on p66 incorrectly identifies Lloyd Helicopters’ owner as Bristow, not Bond Helicopters as it should. Hawker de Havilland Victoria’s Depot Level Maintenance Centre for the General Electric CT7 and T700 turboshaft is being transferred to Bankstown by mid year. HdH then expects the Melbourne engine overhaul facility to close after nearly 60 years of supporting the Australian military.