In order to improve the flight performance of the Martin Jetpack research was undertaken to investigate the aerodynamic issues that were limiting the P-11A Jetpack's flight envelope. Through research of existing ducted-fan aircraft, a flight model describing the unique aerodynamics of the Martin Jetpack was developed using Matlab®/Simulink® software. The dynamic flight model, which can be ran in real time, includes the reactions from: ducted-fans, aircraft body aerodynamics, control surfaces, gyration and landing gear interactions. Abstract Numerous experiments were designed to quantify and validate assumptions used in the development of the model equations. The experiments took advantage of the small size of the Jetpack by designing and building test apparatuses that measured reactions directly on the actual aircraft. This avoided scaling issues that are traditionally encountered when employing wind tunnels for aerodynamic measurements. Abstract Implementing the experimental results into the model led to the modifications of the existing Jetpack airframe to produce the P-11C Jetpack prototype, which significantly improved the performance of the aircraft. The collected flight data was used to validate the model and good agreement was achieved. Abstract Based on this research a new Jetpack prototype (P-12) was developed that combined the flight performance of the P-11C Jetpack with the ability to carry a man or manned sized payload. The model was used to design the layout and to size the control vanes for the P-12 Jetpack. Further research was performed to design larger rotor and stator blades required for the P-12 Jetpack prototype. Abstract The developed model allows the user to efficiently evaluate various control methodologies and changes to key aerodynamic features of the aircraft to aid in the design and flying of the Martin Jetpack. Abstract The outcome of this research is a better understanding of the ducted-fan technology, and via the development of the Jetpack flight model, correctly applying this understanding to improve the Jetpack's flight performance.

Ducted fan vehicles possess a superior ability to maximize payload capacity while minimizing vehicle size. Their ability to both hover and fly at high speed is a key advantage for information-gathering missions, particularly when close proximity to a target is essential. However, the ducted fan's aerodynamic characteristics pose difficulties for stable vehicle flight and therefore require complex control algorithms. In particular, they exhibit a large nose-up pitching moment during wind gusts and when transitioning from hover to forward flight. Understanding ducted fan aerodynamic behavior and how it can be altered through flow control techniques are the two prime objectives of this work. This dissertation provides a new paradigm for modeling the ducted fan's nonlinear behavior and new methods for changing the duct aerodynamics using active flow control. Steady and piezoelectric synthetic jet blowing are employed in the flow control concepts and are compared. The new aerodynamic model captures the nonlinear characteristics of the force, moment, and power data for a ducted fan, while representing these terms in a set of simple equations. The model attains excellent agreement with current and legacy experimental data using twelve non-dimensional constants. Synthetic jet actuators (SJA) have potential for use in flow control applications in UAVs with limited size, weight, and power budgets. Piezoelectric SJAs for a ducted fan vehicle were developed through two rounds of experimental designs. The final SJA design attained peak jet velocities in the range of 225 ft/sec (69 m/s) for a 0.03â x 0.80â rectangular slot. To reduce the magnitude of the nose-up pitching moment in cross-winds, two flow control concepts were explored: flow separation control at the duct lip, and flow turning at the duct trailing edge using a CoandÄ surface. Both concepts were experimentally proven to be successful. Synthetic jets and steady jets were capable of modifying the ducted fan flow to reduce pitching moment, but some cases required high values of steady blowing to create significant responses. Triggering leading edge separation on the duct lip was one application where synthetic jets showed comparable performance to steady jets operating at a blowing coefficient an order of magnitude higher. / Ph. D.