Comprehensive Analysis of a Coaxial Ultralight Rotorcraft and Validation with Full-Scale Flight-Test Data

Feil, Roland; Eble, Daniel; Hajek, Manfred

doi:10.4050/jahs.63.042004

Cited by 5 publications

(5 citation statements)

References 6 publications

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“…Strain gauges were installed according to the halfbridge scheme to measure the moments in the plane of rotation and the vertical plane. A measuring system has already been used on an ultralight rotorcraft (Rapp & Wedemeyer, 2000;Feil et al, 2017). VA115 measuring system was configurated to the task of measuring the loads in the blade during the flight.…”

Section: Research Object Investigation Methodology and Measuring Equi...mentioning

confidence: 99%

Determination of Loads in the Ultralight Helicopter Blades

Dudnik

2023

Aviation

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The article describes research that was carried out on coaxial a single-seat ultralight helicopter Rotorschmiede VA-115 which is manufactured by German firm RS Helikopter GmbH. The purpose of the work was to determine the blades’ loads necessary for further blade fatigue analysis and ground bench tests. The methodology for the load determination consisted of deformation measurements using strain gauges in various flight modes from hovering to maximum speed flight, including climb, descent, acceleration, and braking. Ultralight helicopters occupy the smallest cost niche and, as a rule, full-fledged fatigue studies are not performed for such helicopters. The requirements for ultralight helicopters are also quite loyal, allowing them to pass such experiments. Analysis of the data shows that the amplitude of bending moments on the lower rotor is higher by 1.2 to 2 times the value on the upper rotor. The absolute maximum value of the bending moment is significantly greater at the minimum weight, although the oscillation amplitude becomes smaller. The presented data can be useful for designers of ultralight and UAV helicopters with teetering hinge rotors.

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Section: Research Object Investigation Methodology and Measuring Equi...mentioning

confidence: 99%

Determination of Loads in the Ultralight Helicopter Blades

Dudnik

2023

Aviation

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“…Because the components (II) and (III) were very small, the only component considered in the preliminary design was (I), shear due to transversal load, which was iteratively summarized for each span panel. See equation (5).…”

Section: Design and Methodologymentioning

confidence: 99%

An Eco-Efficient Helicopter Tailplane Hybridized from Flax, Balsa and Carbon

Strohrmann

Hajek

2019

AIAA Scitech 2019 Forum

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A tailplane for an ultralight helicopter was redesigned with the goal of using bio-based materials in a high proportion. Structural requirements were set to the national ultralight certification standards and were also adapted from the performance of the initial design tailplane, which was made of carbon prepreg materials and a foam core. In order to pursue this goal, pre-impregnated flax fiber composites, in combination with a balsa wood core and a small proportion of carbon fiber reinforcements, were used to design a new tailplane. A finite element model was developed, fed by material data from tensile tests and evolving iteratively from coupon and sub-component bending tests. Finally, a 450 mm section of the resulting design was built and a bio-based mass content of approximately 55 % was achieved. The new, hybrid version was analyzed experimentally in terms of weight, stiffness, strength/ failure, damping, and embodied energy, where benchmark data was obtained from either the reference tailplane or the certification specifications. Benefits of the new design were identified in a 2-8 times higher damping ratio, 65% less embodied energy (76.90 MJ kg −1), and reduced carbon footprint (5 kg kg −1), while weight, stiffness, and strength were performing in a sufficient and comparative manner as the reference.

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“…In order to evaluate the control and flapping margins available, the maximum control and flapping deflections need to be known along with the control and flapping deflections during trimmed flight. For the Bo105, the trim data is taken from flight tests and documentation available from GARTEUR activities (24) , and data from a representative ultralight COAX helicopter flight test has recently been published (25) ; the control limits of it are based on personal communication. For the representative AG flight trim data from DLRs experimental vehicle were taken based on a MTOsport 2010 (26) .…”

Section: Wind Turbine and Rotorcraft Datamentioning

confidence: 99%

Wind turbine wake vortex influence on safety of small rotorcraft

Wall

2019

Aeronaut. j.

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The wake vortex of lifting surfaces such as wind turbine blades or fixed-wing aircraft can heavily affect the blade aerodynamics of rotorcraft. Using blade element theory, the pilot control inputs required to mitigate such vortex effects are estimated and compared to the available control margin at the operating condition of interest. In contrast, when no pilot action is performed, the rotor blade flapping caused by the vortex is evaluated and compared to available margins. It is a safety concern when the remaining margins become zero. The influence of the vortex strength, its core radius and orientation to the rotor disk are evaluated and the effect of rotor blade characteristics (Lock number, natural frequency) is investigated.

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Comprehensive Analysis of a Coaxial Ultralight Rotorcraft and Validation with Full-Scale Flight-Test Data

Cited by 5 publications

References 6 publications

Determination of Loads in the Ultralight Helicopter Blades

Determination of Loads in the Ultralight Helicopter Blades

An Eco-Efficient Helicopter Tailplane Hybridized from Flax, Balsa and Carbon

Wind turbine wake vortex influence on safety of small rotorcraft

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