Design and Fabrication of an Rc Vertical Takeoff and Landing Air Vehicle Project Reference No.: 39S Be 0092

DESIGN AND FABRICATION OF AN RC VERTICAL TAKEOFF AND LANDING AIR VEHICLE PROJECT REFERENCE NO.: 39S_BE_0092

COLLEGE : R V COLLEGE OF ENGINEERING, BENGALURU BRANCH : DEPARTMENT OF MECHANICAL ENGINEERING GUIDE : PROF. KESHAVAMURTHY Y C STUDENTS : MR. ABHISHEK H V MS. MAANASA BHAT MS. MANDARA YOGARAJ MR. PAURAV SARDESHMUKH

INTRODUCTION: Unmanned aerial vehicles (UAV) are those which fly with in direct human control and are guided and controlled by a remote device using radio frequency communication. These UAV’s have emerged as an alternative in instances where they are capable of capturing high definition images and videos, apart from feeding real-time data to the controlling base station in all weather conditions. Their features such as easy flight over large distances, ease of transport at ion and assembly, smooth and simple operating procedure along with less operation and maintenance cost are attracting their usage and commercialization. The global UAV market is categorized in to micro, mini, medium and heavy based on their weight, range and endurance. The global small (micro/mini) UAV market is expected to grow at Compound Annual Growth Rate (CAGR) of 12.31%, and reach $1.9 billion by the end of 2020. Increase in civil and military applications is the key driving factor for the global small UAV market.

There is an ongoing search for the next generation airliner configuration. A vehicle that is capable of vertical take-off and landing like a helicopter and which is able to cruise longer distances and provide better fuel efficiency in forward flight like an aircraft is the ideal air vehicle to bridge the gap between the conventional aircraft and rotary vehicles. VTOL (Vertical take-off and Landing) Air Vehicle is the perfect configuration that combines the advantages of both fixed wing aircrafts and helicopters and minimises their disadvantages.

OBJECTIVES:

1. Design of an RC air vehicle using a combination of aerodynamic flight equations and XFLR5 software to produce lift force of 20N through iterative refinement. 2. Structural and Flow analysis of RC air vehicle prime components. 3. Devise a mechanism to house tilt rotor and its actuation control. 4. Fabricate and conduct flight test of VTOL air vehicle to confirm design specifications.

METHODOLOGY:

Volumetric, payload and velocity constraints were defined around which the air vehicle had to be designed. A top level design approach was used. The aircraft design was carried out using a combination of aerodynamic flight equations and XFLR5 software. An airfoil having high lift to drag coefficient ratio was chosen by comparing various available airfoils from UIUC Database.

The tilt rotor mechanism uses servo and gear system to rotate the motor shaft supported by bearings. The shaft and the gears were designed using design equations. Suitable bearings were chosen after conducting a comparative study between various commercially available bearings. SOLIDWORKS 2014 was used for the 3D modelling of air vehicle.

Structural analysis and flow analysis of the model was carried out using ANSYS V14.5 and STAR CCM+ V9.06 FEA packages. Materials having high strength to weight ratio were selected for fabrication of the plane. A trade off analysis was done between different suitable materials on the basis of material properties.

Thrust rig test was conducted on the motors to determine the actual amount of thrust available for lift off. A graph of lift off speed v/s load was plotted. Pre flight tests were conducted to ensure smooth and stable flight. The tilt frame was stabilised for pitch, yaw and roll motions. PID tuning was done to calibrate the control system.

CONCLUSION: The prototype demonstrated successful vertical takeoff and landing. Transition was tested by tilting the rotors in steps of 10 degrees. The results are given below.

Flight Tilt Observations Pilot corrections Attempt Angle  Slight forward body tilt  Smooth stable transition 1 10 -  Stable forward flight  Negligible altitude drop  Slight forward body tilt  Smooth stable transition Increased throttle to 2 20  Stable forward flight maintain altitude  Slight altitude drop  Slight forward body tilt  Smooth stable transition High throttle input 3 30  Stable forward flight after tilt to avoid  Noticeable altitude drop hard landing during forward flight Immediate tilt  Slight forward body tilt reversal to zero 4 40  Smooth stable transition degree to avoid  Rapid altitude drop crashing.

A Vertical takeoff and Landing (VTOL) air vehicle was successfully designed and fabricated. The design was validated by analysis and flight tests. The tilt rotor concept was demonstrated.

FUTURE SCOPE:

The project lies in making the aerial vehicle completely autonomous, eliminating human intervention. The VTOL air vehicle can be adapted to different applications with minor changes in the design.