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Technical Paper

2D Ice Shape Scaling for Helicopter Blade Profiles in Icing Wind Tunnel

2015-06-15
2015-01-2129
Therefore, ice shapes resulting from tests with the same icing similarity parameters are compared to each other allowing the assessment of icing scaling laws for helicopter applications. This paper presents the icing scaling laws used at Airbus Helicopters on blade profiles, the different test set ups and test models and it presents the comparison of the ice shapes collected during the icing wind tunnel test campaigns. ...Different Airbus Helicopters main rotor blade profiles were tested in different icing wind tunnels and for different icing conditions. ...One of the objectives of the accretion tests was to validate the use of 2D icing scaling laws established for fixed wing aircraft on helicopter blade profiles. Therefore, ice shapes resulting from tests with the same icing similarity parameters are compared to each other allowing the assessment of icing scaling laws for helicopter applications.
Technical Paper

2D Polar Assessment in Icing Wind Tunnel for iced Helicopter Blade Profiles

2015-06-15
2015-01-2127
A helicopter blade profile was tested in the DGA Aero-engine Testing's icing altitude test facility S1 in Saclay, France during the winter of 2013/2014. ...The airfoil was a helicopter main rotor OA312 blade profile made out of composite material and with a metallic erosion shield.
Technical Paper

A CFD Approach for Predicting 3D Ice Accretion on Aircraft

2011-06-13
2011-38-0044
In this work, a newly developed iced-aircraft modeling tool is applied to wings, engine inlets, and helicopter rotors. The tool is based on a multiscale-physics, unstructured finite-volume CFD approach and is applicable to general purpose aircraft icing applications. ...The goal of the model is to improve the fidelity of ice accretion modeling on dynamic geometries and for three-dimensional ice shapes typical of helicopter rotors. The numerical formulation is discussed and presented alongside 2D and 3D static validation cases, and dynamic helicopter rotors. ...The numerical formulation is discussed and presented alongside 2D and 3D static validation cases, and dynamic helicopter rotors. The present results display good validation for predicting ice shape on a variety of geometries, and a strong initial capability of modeling ice forming on helicopters in forward flight.
Technical Paper

A Description of the VTOL Airline System

1968-04-29
680275
Two types of service are recognized: metropolitan area service, connecting airports with downtown and suburban heliports -- which will continue to be done by helicopters; and inter-city downtown to downtown service employing high speed future type VTOL aircraft. ...Currently operating VTOL airlines are demonstrating the practicality of metropolitan area helicopter service. Advanced, high speed VTOL vehicles, introduced in the 1970’s will make extension of current routes possible to inter-city service.
Technical Paper

A Dynamic Crash Test of an H-25 Helicopter

1963-01-01
630482
An H-25A Piasecki helicopter has been employed in recreating a “typical” accident occurring with both longitudinal and vertical velocity components at impact. ...For the helicopter, large magnitude, short duration, accelerations have been observed. By contrast, accelerations of smaller magnitude but with relatively longer duration were found for transport type aircraft by NACA.
Technical Paper

A History of Ice Protection System Development at Sikorsky Aircraft

2003-06-16
2003-01-2092
Sikorsky Aircraft has conducted icing research and ice protection system development for helicopters over the past 58 years and the pace of that work has accelerated during the past two decades. ...Sikorsky participated in several helicopter icing flight tests, conducted wind tunnel tests of scale models and full-scale components, tested simulated ice shapes, and developed analytical tools for use in the design, certification, and qualification for flight in icing conditions. ...The UH-60A BLACK HAWK electrothermal rotor ice protection system, developed in the late 1970s, has been installed in 2400 H-60 helicopters and it remains one of the most effective rotor ice protection systems. This paper traces the history of Sikorsky icing tests, presents information on the development of the BLACK HAWK rotor ice protection system, discusses data acquired during model-scale and full-scale airfoil and rotor icing tests, describes methods used to support ice protection system development and qualification/certification, and includes the status of BLACK HAWK Growth Rotor Blade icing qualification and S-92 icing certification.
Technical Paper

A Mesh Based Approach for Unconventional Unmanned Airship Added Masses Computation

2013-09-17
2013-01-2191
The motion of vehicles like airships and ships can be addressed only by keeping into account the effect of added masses, while in case of aircrafts and helicopters this contribution is usually neglected. Lighter Than Air flight simulation, unmanned airships flight control system, airships flight dynamics are typical applications in which added masses are fundamental to achieve an effective and realistic modeling.
Technical Paper

A Method for Selecting Aircraft to Meet Coast Guard System Requirements

2002-04-16
2002-01-1544
The following types of vehicles were considered as competing: seaplanes, helicopters, VTOL, ekranoplans and patrol vessels. The results of the carried out comparisons have shown the capacity of work of the method and its sensitivity to all of the important mentioned above factors.
Standard

A Method of Ground Resonance Testing for Helicopters

1985-01-01
CURRENT
AIR883
(This document supersedes and cancels AIR 12) 'Ground resonance' is a term which originated in the early days of autogiro development in this country. It is a somewhat ambiguous term as the conditions it describes usually occur at the ground but do not have any association with the common expression 'ground effect'. However, the troubles usually associated with 'ground resonance' do occur when the ship is on or near the ground.
Technical Paper

A Methodology for the Prediction of Rotor Blade Ice Formation and Shedding

2011-06-13
2011-38-0090
An integrated approach for modeling the ice accretion and shedding of ice on helicopter rotors is presented. A modular framework is used that includes state of the art computational fluid dynamics, computational structural dynamics, rotor trim, ice accretion, and shedding tools.
Technical Paper

A New VTOL Propelled Wing for Flying Cars: Critical Bibliographic Analysis

2017-09-19
2017-01-2144
It is expected to equip new aerial vehicle concepts that aim to compete against helicopters and tilt rotors. They aim achieving very good performance at very low speed (5 to 30 m/s) by mean of an innovative concept of morphing ducted-fan propelled wing that has been designed to maximize the lift force. ...Even if the results are still preliminary, they allow evidencing a good energy efficiency of the vehicle against helicopters.
Technical Paper

A Perspective Look at VTOL

1967-02-01
670686
Thus the development of the low-speed helicopter necessarily emerged first. Although the evolution of VTOL vehicles has been slow and difficult, progress continues toward the original goal of a safer more effective vehicle for transportation through the air.
Technical Paper

A Perspective on the First Century of Vertical Flight

1999-10-19
1999-01-5584
By World War II, the problem of achieving practical vertical flight had been solved with the introduction of the helicopter, but higher speeds were desired. Vertical and/or Short Take-Off and Landing (V/STOL) aircraft are intended to combine the vertical take-off and landing capability of the helicopter with the high forward speed of an airplane. ...Vertical and/or Short Take-Off and Landing (V/STOL) aircraft are intended to combine the vertical take-off and landing capability of the helicopter with the high forward speed of an airplane. The key problems with developing a practical vertical take-off and landing aircraft have been the same as with the early fixed-wing aircraft: high thrust to weight and adequate controllability.
Technical Paper

A Perspective on the Helicopter Industry

1982-02-01
821507
The Helicopter Association International (HAI) is an independent organization of close to 1000 member companies who own, operate or manufacture helicopters. HAI represents and promotes the helicopter interests of our members to government, business and industry, the news media and the public. ...Much of this presentation is equally applicable in other countries; but for the purpose of this synopsium, it is aimed primarily at the domestic helicopter situation within the United States. The helicopter provides unique benefits to our society and our economy. ...The Helicopter Association International (HAI) is an independent organization of close to 1000 member companies who own, operate or manufacture helicopters.
Technical Paper

A Potential Solution for High-Efficiency Aircraft Powerplants - the Scotch Yoke X-Engine Aero-Diesel

2017-09-19
2017-01-2042
Given the efficiency advantage of 4-stroke turbo-diesel cycle over turbine engines, a study reveals that diesel X-engines may be a preferable solution to turbine engines for airplanes, helicopters and UAVs up to approximately 60000 lbs max. weight @takeoff. Calculations using existing turbine-powered aircraft as a baseline indicate potential for 35 to 50% lower fuel consumption with no compromise to maximum takeoff weight, payload, range, cruise speed, maximum speed or takeoff power.
Technical Paper

A Prototype Flight-Deck Airflow Hazard Visualization System

2004-11-02
2004-01-3120
Airflow hazards such as turbulence, vortices, or low-level wind shear can pose a threat to landing aircraft and are especially dangerous to helicopters. Because pilots usually cannot see airflow, they may be unaware of the extent of the hazard. ...We have developed a prototype airflow hazard visual display for use in helicopter cockpits to alleviate this problem. We report on the results of a preliminary usability study of our airflow hazard visualization system in helicopter-shipboard operations.
Technical Paper

A Quantitative Method for Studying Human Arterial Baroreflexes

1991-07-01
911562
We describe a new system that delivers precise, stereotyped pressure changes to the human neck and elicits neurally-mediated heart rate changes. The centerpiece of this system is a Silastic chamber that is strapped to the anterior neck. This chamber is connected to a stepping-motor controlled bellows assembly. A strain-gauge transducer measures the intensity of pressure changes. The entire system is controlled by microprocessors, and both stimuli and responses are displayed on a digital oscilloscope. The end-product of this system is a reproducible baroreceptor stimulus-cardiac response relation that can be recorded rapidly and safely in astronauts in space.
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