The PSU Zephyrus is a

human-powered aircraft A human-powered aircraft (HPA) is an aircraft belonging to the class of vehicles known as human-powered transport. As its name suggests, HPAs have the pilot not only steer, but power the aircraft (usually propeller-driven) by means of a system ...

being constructed by the

Penn State #Redirect Pennsylvania State University The Pennsylvania State University (Penn State or PSU) is a Public university, public Commonwealth System of Higher Education, state-related Land-grant university, land-grant research university with ca ...

AERSP 404H team. It is a

composite material A composite or composite material (also composition material) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a ...

, single-seat, single

propeller A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...

, high-wing airplane. The Zephyrus is designed to compete in the

Kremer prize The Kremer prizes are a series of monetary awards, established in 1959 by the industrialist Henry Kremer. Royal Aeronautical Society Human Powered Flight Group The Royal Aeronautical Society's "Man Powered Aircraft Group" was formed in 1959 b ...

sport competition.

Development

The PSU Zephyrus was developed to compete in the Kremer's prize sport competition. The basic mission goal is to traverse an equilateral triangle with sides of 500 meters once in each direction in seven minutes. The competition specifies a minimum average airspeed of 5.0 m/s during the flight. In addition, for a flight to be considered official, the airspeed cannot drop below 5.0 m/s for a period of more than 20 seconds. The aircraft is also being developed and constructed as a fulfillment of the course requirements of Penn State's AERSP 404H course.

Design

Fuselage

The

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

was sized based a dimension range of a 5’10”(1.78 m) pilot and the assumption that the pilot could output the necessary

power-to-weight ratio Power-to-weight ratio (PWR, also called specific power, or power-to-mass ratio) is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measurement ...

to fly the aircraft will be no greater than 1.78 m. Constraints include minimum widths for pilot comfort and desired

center of gravity In physics, the center of mass of a distribution of mass in space (sometimes referred to as the barycenter or balance point) is the unique point at any given time where the weighted relative position of the distributed mass sums to zero. For ...

of the aircraft. The shape of the pod was designed to be a low-drag body that will not generate lift regardless of angle of attack. The length of the shape was reduced to allow for aircraft maneuverability in crosswind. The internal structural members are designed to firmly hold the seat configuration in place, yet still provide a maximum field of vision for the pilot. Structural members attach to the main boom at a hard-point located behind the trailing edge of the wing.

Propeller

To successfully complete the challenge, it was determined that the propeller would need to produce 27.5 N of

thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that ...

when cruising at 11.5 m/s and spinning at 135

rpm Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 def ...

. To meet these requirements, the propeller design underwent many alterations, with the final design broken into two components.

Wing

Starting from a parent aircraft approach, primarily using the Musculair 1 and 2, but also including the Monarch B,

MIT Daedalus The Massachusetts Institute of Technology, MIT Aeronautics and Astronautics Department's Daedalus is a class of three human-powered aircraftJohn McIntyreMan's Greatest Flight, ''AeroModeller'', August 1988 (in files of Royal Aeronautical Society ...

, and Velair models, a first iteration choice for an airfoil was made. A modified version of the FX-76MP, as used for the Musculair 2 was chosen. Taking characteristics from this airfoil, using an initial weight buildup, the wing planform size was determined. Then, assuming a take-off weight of 81 kg (27 kg empty weight), sea-level air density, and using a CL at cruise of 0.8.

Control Surfaces

Ailerons An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement around ...

were designed as a piano hinge attached near the upper surface, so the upper surface incorporates the leading edge radius, so that the upper surface maintains smooth flow. This design maximizes weight efficiency and construction ease.

Specifications

References

"Student sailplane makes first flight, class prepares for competition", Penn State News, May 3rd, 2011. {{refend Human-powered aircraft High-wing aircraft Single-engined tractor aircraft