Browse Topic: Refueling
This SAE Information Report contains definitions for hydrogen fuel cell powered vehicle terminology. It is intended that this document be a resource for those writing other hydrogen fuel cell vehicle documents, specifically, Standards or Recommended Practices.
During helicopter air-to-air refueling the rotor of the helicopter might enter the slipstream of the tanker aircraft's propeller. Based on blade element momentum theory, the impact of the accelerated air within the propeller slipstream on rotor blade aerodynamics (thrust, rolling and pitching moments) can be solved analytically. Also, DLR's comprehensive rotorcraft code has been used with the Pitt-Peters induced inflow plus rotor-rotor interference model. Additionally, DLR's free-wake code was used for both the propeller and the helicopter main rotor, including mutual wake-wake-interactions. The helicopter rotor's collective and cyclic controls needed for disturbance rejection are computed with all these models for a typical air-to-air refueling scenario without and with blade flapping motion. A propeller wake affecting the retreating side of the rotor requires much larger control inputs to retrim than an impingement on the advancing side. The results of all modelling approaches are compared to each other and generally a reasonably good agreement is found, despite their very different levels of complexity and computational effort.
Several efforts have been made to develop Flight Test Maneuvers for Handling Qualities evaluations, aimed at quantifying the effects of vehicle characteristics and assistance systems on a Helicopter Air-to-Air Refueling mission profile. However, these Flight Test Maneuvers have not achieved widespread adoption, likely due to the substantial logistical challenges associated with tanker deployment. Depending on a tanker aircraft not only incurs significant costs but also requires extensive organizational effort and prior testing, before Handling Qualities can be evaluated for the aerial refueling capabilities of a new rotorcraft design. Additionally, these available Flight Test Maneuver setups are not standardized or widely applied to the same degree as Mission Task Elements of the Aeronautical Design Standard, which limits repeatability and comparability. A new approach is proposed to address these limitations by introducing a repeatable, standardized method to reveal Handling Qualities deficiencies considering a worst-case situation of Helicopter Air-to-Air Refueling. This approach involves analyzing drogue motion to create a synthetic, deterministic target forcing function, based on the summation of several sine waves. Resulting laws of motion are applied to a target tracking task replicating a drogue chasing scenario by projecting all required references into the pilots' field of view. Piloted simulator studies conducted at the Air Vehicle Simulator (AVES) of the German Aerospace Center (DLR) demonstrate a high degree of similarity in pilot control behavior between the proposed Flight Test Maneuver and actual simulated Helicopter Air-to-Air Refueling.
Refueling mid air is considered as important force multiplier for e.g. conducting search and rescue operations. Due to close proximity to the tanker, the refueling hose and drogue as well as the receiver can be strongly affected by the tanker's wake. Thus, the refueling drogue extended from the tanker by a hose is often oscillating from turbulence. Contact with the tanker has to be established by positioning the receiver's refueling probe within the tanker's drogue. During qualification training pilots are instructed to not focus on the drogue, due to its oscillations. This is done since chasing the drogue often leads to over-controlling and therefore mostly to a failed contact attempt. The presented research aims for improving today's Helicopter Air-to-Air Refueling (HAAR) as well as related training efficiency by a gain of understanding in this phenomenon. Therefore, the HAAR real-time simulation scenario at German Aerospace Center's (DLR) Air Vehicle Simulator (AVES) was extended with a multi body hose and a probe/drogue contact model to enable realistic contact initiation. During a piloted campaign, a total of six pilots with different levels of HAAR experience conducted the maneuver. This paper presents an analysis of obtained eye tracking data with regards to gaze entropy, total fixation duration on defined areas of interest and corresponding time history of control inputs. Potential links between gaze entropy and perceived workload that might be observed in the data are also discussed. Results show that the metrics can highlight differences in successful and unsuccessful attempts for contact of HAAR experienced and inexperienced pilots.
This standard specifies the communications hardware and software requirements for fueling hydrogen surface vehicles (HSV), such as fuel cell vehicles, but may also be used where appropriate, with heavy-duty vehicles (e.g., busses) and industrial trucks (e.g., forklifts) with compressed hydrogen storage. It contains a description of the communications hardware and communications protocol that may be used to refuel the HSV. The intent of this standard is to enable harmonized development and implementation of the hydrogen fueling interfaces. This standard is intended to be used in conjunction with the hydrogen fueling protocols in SAE J2601 and nozzles and receptacles conforming with SAE J2600.
ABSTRACT Inspired watching Glenn Curtiss landing to refuel on his historic 1910 flight from Albany to New York City, the almost 5-year old John McDonald "Johnny" Miller decided he wanted to be a pilot, a decision reinforced five years later in a chance encounter with famed aviatrix Ruth Law (3rd licensed woman pilot in America) at the Curtiss Flying school in Mineola, Long Island. Miller taught himself to fly in used WWI Jenny from a text by Captain Horatio Barber, a book Miller still had in his family home in Poughkeepsie, NY eighty years later. His career in aviation, begun in a $1,500 used WWI aircraft, would span eight decades and see him as an Eastern Airline pilot flying jets - a career captured in his email address adopted in his ninth decade from jennys2jets, but Miller was most famous for being the man who beat Amelia Earhart in the first transcontinental Autogiro flight in 1931 and the 1939-1940 experimental Autogiro Airmail Route between the 30th Street Post Office roof in Philadelphia and Camden, NJ. In between, Miller supported himself with maintenance work on bootleggers airplanes and airshow performances, one of which resulted in the death of 'Al' Wilson whose replica Curtiss biplane fatally crashed in a mock dogfight with Miller's PCA-2 Autogiro. Miller's career spanned 85 years and, at his death at 102 & 1/2, he was still a licensed and active pilot. He had thrilled thousands with his Autogiro exhibitions, and while he was not the first, his daring Autogiro 'loop-the-loop' never failed to have the crowd cheering and was captured in the 1935 film Ladies Crave Excitement. Miller was an outsider - not part of the Pitcairn business enterprise which championed Earhart and, from such a truly unique vantage point, was in a special position to observe and comment. His triumphant transcontinental flight in 1931 and the 1939-1940 Autogiro Airmail Route neatly bracket the age of the American Autogiro - John McDonald Miller was part that decade, and his frequent writings provide a unique record and attest to the fabulous life of this American original.
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