Refine Your Search



Search Results

Technical Paper

Computer Aiding for Low-Altitude Flight Simulation to Flight: A Case Study

The system was developed using extensive piloted simulation and then implemented in a UH-60 Blackhawk helicopter for flight development and evaluation. A close correlation between simulation and actual flight was found; however, in flight overall pilot workload increased and performance decreased.
Technical Paper

US Army UH-60M Helicopter Main Rotor Ice Protection System

Sikorsky Aircraft Corporation designed a new advanced technology composite main rotor blade for a growth BLACK HAWK helicopter, now designated the UH-60M. The UH-60M main rotor blade has new airfoils, a larger blade chord, and a swept, tapered, anhedral tip, with a rotor ice protection system (RIPS) similar to that of the UH-60A/L helicopter. The UH-60A/L RIPS control system was retained and the new blades were fitted with heater elements similar in geometry to those of the UH-60A/L main rotor blades, but with the outboard extent of the heater mat 10 inches more inboard than that of the UH-60A/L and the woven wire heater resistance was changed to maintain the same power density as the UH-60A/L. Analyses and S-92A® helicopter artificial and natural icing flight test data show that the increased blade chord, improved airfoils, and advanced blade geometry result a minimal change in BLACK HAWK icing flight characteristics.

Sikorsky’s autonomous Black Hawk helicopter takes flight

Sikorsky tested a new full-authority, fly-by-wire flight control technology kit for the first time on a Sikorsky UH-60 Black Hawk medium-lift utility helicopter. The flight marked the beginning of the flight test program for the soon-to-be optionally piloted rotorcraft.

SES to outfit Sikorsky UH-60A Black Hawk helicopters with Unitech Composites weapons pylons

Unitech Composites, a Unitech Aerospace company in Hayden, Idaho, is providing its Lightweight Armament Support Structure (LASS) composite weapons pylons to maintenance, repair, and overhaul (MRO) company Science and Engineering Services (SES) in Columbia, Md., for use on Sikorsky UH-60A Black Hawk helicopters the U.S. Army is supplying to the government of Afghanistan through the U.S. Department of Defense’s Foreign Military Sales (FMS) program.
Technical Paper

A Review of Recent Programs and Future Plans for Rotorcraft In-Flight Simulation at Ames Research Center

A new flight research vehicle, the Rotorcraft-Aircrew Systems Concepts Airborne Laboratory (RASCAL), is being developed by the U.S. Army and NASA at Ames Research Center. The requirements for this new facility stem from a perception of rotorcraft system technology requirements for the next decade together with operational experience with the Boeing Vertol CH-47B research helicopter that was operated as an in-flight simulator at Ames during the past 10 years. Accordingly, both the principal design features of the CH-47B variable-stability system and the flight-control and cockpit-display programs that were conducted using this aircraft at Ames are reviewed. Another U.S. Army helicopter, a Sikorsky UH-60A Black Hawk, has been selected as the baseline vehicle for the RASCAL. The research programs that influence the design of the RASCAL are summarized, and the resultant requirements for the RASCAL research system are described.
Technical Paper

Helicopter Cargo -- New Opportunities Through Technology Transfer

The value of helicopter-augmented air cargo has been demonstrated and greater exploitation of its opportunities has awaited only the emergence of a low-cost, reliable cargo helicopter. One such aircraft is the Sikorsky S-70C, a close derivative of the U.S. Army UH-60A Black Hawk utility transport helicopter, recently certificated by the U.S. FAA for cargo transport and related missions. The use of such advanced helicopters to augment fixed-wing priority express service between major cities is shown to offer substantial time savings, and corresponding improvements in a forwarder's market share, at a disproportionately small increase in total cost.
Technical Paper

Advanced Overrunning Clutch Technology

This paper summarizes the results of a 3 year research program to advance the state-of-the-art in helicopter free-wheel units (overrunning clutches) by permitting operation at 20,000 rpm. By designing the free-wheel unit to operate at engine input speed instead of at the speed of the 2nd reduction where it is usually located, the torque, and hence size and weight of the unit, will be reduced. High-speed designs, test results, and application of the designs to the UH-60A BLACK HAWK are presented for spring, sprag, and ramp roller types of overrunning clutches.
Technical Paper

A History of Ice Protection System Development at Sikorsky Aircraft

Modern rotorcraft must have the capability to operate in all-weather conditions. 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. Engine inlets, airspeed systems, main rotor droop stops, and windshields are generally protected by thermal anti-icing systems. When rotor ice protection is required, rotors are protected with electrothermal deice systems. 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.

Aerospace & Defense Technology: February 2019

Ruggedizing Commercial-Grade Computers into MIL-Hardened Systems An Introduction to PCM Heat Sinks Eye Tracking Technology Improving the Skills Gap, Efficiency, and Quality Assurance in Aerospace Manufacturing Streamlining EMC Solutions for Avionics Interfaces Hardware Design of a High Dynamic Range Radio Frequency (RF) Harmonic Measurement System. Using RISC-V to Simplify Data Logging in Space Novel Characterization Methods for Anisotropic and Mixed-Conduction Materials Seven new characterization methods have been developed for the specialized materials used in state-of-the-art electronic and optoelectronic devices. Circuit Models for Robust, Adaptive Neural Control Understanding a nematode's simple circuit could provide a foundation for understanding much more complex behaviors.
Technical Paper

Comparison of Elastic and Rigid Blade-Element Rotor Models Using Parallel Processing Technology for Piloted Simulations

A piloted comparison of rigid and aeroelastic blade-element rotor models was conducted on the Crew Station Research and Development Facility (CSRDF) at Ames Research Center. FLIGHTLAB, a new simulation development and analysis tool, was used to implement these models in real time using parallel processing technology. Pilot comments and quantitative analysis performed both on-line and off-line confirmed that elastic degrees of freedom significantly affect perceived handling qualities. Trim comparisons show improved correlation with flight test data when elastic modes are modeled. The results demonstrate the efficiency with which the mathematical modeling sophistication of existing simulation facilities can be upgraded using parallel processing, and the importance of these upgrades to simulation fidelity.
Technical Paper

Advancements in Control/Display Systems for Army Helicopters

A new generation of Army helicopter crew station is being developed today to meet the challenges of missions required by Army Aviation. The scout mission exemplifies the demands that can be placed upon the aircraft and crew. Scout missions require nap-of-the-earth (NOE) flight during day, night, and adverse weather conditions. Such a requirement demands the highest degree of compatibility between aircraft systems and crew. To meet this challenge, the US Army is currently developing an improved scout helicopter called the Army Helicopter Improvement Program (AHIP). Several enhancements and innovations in crew station design are an integral part of the program. Improvements in the AHIP control/display system reduce head-down cockpit activities allowing more time for head-up flight of the aircraft; especially important during NOE flight.
Technical Paper

Flight Test of 35GHz MMW Radar Forward Sensor for Collision Avoidance

Collision avoidance is of concern to all aircraft, requiring the detection and identification of hazardous terrain or obstacles in sufficient time for clearance maneuvers. The collision avoidance requirement is even more demanding for helicopters, as their unique capabilities result in extensive operations at low-altitude, near to terrain and hazardous obstacles. To augment the pilot's visual collision avoidance abilities, some aircraft are equipped with “enhanced-vision” systems or terrain collision warning systems. Enhanced-vision systems typically project raw images from infrared or radar sensors, and can require a high degree of pilot interpretation and attention, as the sensor returns may be sparse and are devoid of memory from previous sensor returns. Terrain collision warning systems rely on stored terrain maps that are of low resolution and accuracy which do not represent hazards to the aircraft placed after map sampling.

Aircraft Flight Control Systems Descriptions

This SAE Aerospace Information Report (AIR) supplies information on the flight control systems incorporated on various current and historic fixed wing, rotary wing, and tilt rotor aircraft. A brief description of the aircraft is followed by a description of the flight control system, some specific components, drawings of the internal arrangement, block diagrams, and schematics. System operation redundancy management is also presented.
Technical Paper

Design, Fabrication and Test of a Complex Helicopter Airframe Section

Under a jointly sponsored Army/NASA contract NAS1-13479 (Army Structures Laboratory, USARTL (AVRADCOM), and NASA-Langley) Sikorsky Aircraft has been conducting programs for the design, fabrication and test of advanced composite airframe structures. This paper will present the progress of Phave IV of the contract involving cabin roof structures. The cabin roof structure is one of the most complex regions in an all composite helicopter airframe. The roof contains highly loaded joints where the major frames and beams intersect and high concentrated loads from the main gear box are introduced. Under Phase IV the design of a roof structure has been completed which consists of all graphite/epoxy structural elements bonded as an assembly without any mechanical fasteners. Fabrication used aluminum tooling with control on all mating surfaces to provide accurate bondlines. The results of static tests are presented.
Technical Paper

Sealed Lead-Acid Battery Performance and Present Aircraft Applications

The United States Navy has flown Sealed Lead-Acid Batteries (SLA) for approximately 15 years. The first SLA aircraft batteries were cylindrical cell design and evolved to a prismatic design to save weight, volume, and to increase rate capability. This paper discusses the evolution of the SLA aircraft battery designs, present SLA battery performance, and battery size available along with their aircraft applications (both military & commercial). The paper provides some of the reliability data from present applications. Finally, the paper discusses future evolution of the SLA technology required to improve performance and to remain the technology of choice over other sealed aircraft battery designs.
Technical Paper

Army Aviation Operations in Icing Conditions

Army aviation is vulnerable to in-flight and pre-flight icing because of the nature of its operations, flying primarily slow rotorcraft at low altitudes from non-traditional airfields with limited facilities. Icing causes mission delays during ground deicing of aircraft, and mission cancellations and aborted flights occur because of forecast or actual in-flight icing. CRREL, in coordination with the Army Aviation Directorate of Combat Developments, surveyed 35 aviation commands worldwide, and analyzed Army Safety Center accident and incident records. This paper presents the results, which identify and quantify the effect of icing on Army aviation. The severity of icing's impact on mission accomplishment is largely a function of aircraft type flown, location, mission, and airfield facilities.