Date of Award

12-2022

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Aerospace, Physics, and Space Sciences

First Advisor

Ralph D. Kimberlin

Second Advisor

Brian A. Kish

Third Advisor

Isaac Silver

Fourth Advisor

David C. Fleming

Abstract

Electric aircraft are on the horizon. Both industry and regulators have an abundance of flight tests ahead to ensure safe operation of these new aircraft. Conventional performance standards regaurding edurance, climb performance and cruise conditions are largely not applicable to assessing an electrically propulsed aircraft. While battery technologies are the current barrier for electric aircraft, there also hasn’t been much flight testing to reveal their unique performance trends. This experiment focus’s on characterizing some of these performance trends obtained through a level flight and climb test in the Pipistrel Velis Electro. The rate-of-climb did not exhibit a decrease when the Velis Electro climbed in altitude, unlike conventional combustion engines, which all become oxygen limited eventually. The speed for best rate of climb (Vy) was found to be ~75 KIAS while the speed for best angle of climb was found to be ~63 KIAS. The averaged propeller efficiency was found to be ~65 KIAS and pitched specifically to improve the climb performance of the aircraft. However, this caused the propeller to be significantly less appropriate for higher cruise speeds especially in a light weight configuration. The Velis electro is electrically RPM limited to 2500 RPM. This means Vh is ultimately restricted by the RPM cap while there is still power available from the batteries to be delivered to the motor. Throughout the level acceleration and climb tests, the speeds were often RPM limited, creating an inversed trend in the power (kW) vs airspeed (KIAS) plot.

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