1. Unmanned Powerline Surveillance Aircraft Group Name: Watchmen
Brock Arp, Cameron Whigham, Lorenzo Stewart, Wade Vine
ISYE Aerospace Senior Design Project
Methodology
Materials/Manufacturing
Abstract
Engine Selection
The purpose of our project is to provide powerline workers and linemen with a safe way to inspect the power lines. Our Aircraft is an UAV that is capable of surveying 200 linear miles in a normal working shift. The aircraft will be launched/landed and operated from an F-150 pickup truck with a facilitated launch mechanism attached. The aircraft must maintain an altitude of ft. It will be recovered via net that will extend from the truck as the plane comes in for a landing, This will eliminate the need for landing gear. The goal for this project was to create a long range stable aircraft that weighed less than 55 pounds.
Our method for bringing this design to fruition was of a multistep nature. The first step consisted of brainstorming multiple early designs then incorporating the best parts of each into a singular initial design. This initial design was then fleshed out into a basic theoretical working aircraft through the use of multiple simple mathematical models found primarily in Aircraft Design: A Conceptual Approach by Daniel Raymer. It was during this stage that our design underwent several alterations, first from a tilt-rotor to a tilt-wing before finally settling as a more standard design aided by a launch mechanism. This theoretical was then modeled in the CAD software Solidworks where we had it undergo multiple simulations to confirm the veracity of the numbers we had previously found.
The idea was to select an engine that generated enough thrust to exceed the 16.2lbf drag which was calculated within Flow Simulation in SolidWorks.This would allow for acceleration of plane and steady flight.
Material selection was paramount for our design due to the weight constraint and the high stress for a captured landing. An EPP (Expanded Polypropylene) foam such as AeroCell or Elapor that is lightweight, easy to mold (cut with a hot wire), and very durable to withstand the stresses of flight and the landing will make up the wing and tail. There is a rubber bladder in the wing to hold the fuel, and a lightweight aluminum rod running through the wing for support. These materials will make the aircraft easy to manufacture and be cost effective. The skin of the aircraft can be an epoxy coat, or fiberglass tape depending on the preference of the user.
Our team utilized the 2.5hp of a DLE 20CC-Gas Piston-Prop Engine as our initial engine. We then did a propeller efficiency calculation to see what propeller could satisfy the Velocity requirements of 40 mph and 5000 ft altitude. It was a success verifying our initial selection to be adequate. This was shown by rate of efficiency being only needed to be 69% with historical data showing that props only lose 20% within efficiency for piston prop engines under most conditions which would equate to 80% being greater than 69%. Creating a Factor of Safety of 1.15 for thrust requirements via efficiency. The propeller that helps make our system achieve the desired 16.2lbf thrust would have a diameter of 2.14ft each.
Design Specifications
Flight Parameters:
Takeoff Weight: 35 lbs Fuel Weight:15 pounds
Cruise Velocity: 40 mph Flight Altitude: ft
Aircraft Planform:
Wingspan: ft Wing Chord: 1.5 ft
Wing Area : ft^2 Aspect Ratio: 7.35
Wing Lift Coefficient: Wing Loading: lb/ft^2
Taper Ratio: 1 Airfoil Lift Coeff.: 0.667
Wing Sweep: None L/D Ratio:
Drag Coeff.: Zero Lift Drag Coeff.:
Airfoil: DAE -11:
Results and Discussion
Upon completion our design will be able to fly and return to base either for refueling or storage upon completion. Optimization of the engine-propeller combination would help to increase thrust or or minimize specific fuel consumption. Part of our future work is an extensive trade study to see which piston-prop combination would grant us the best thrust while minimizing SFC. This would help us to fly faster for longer durations. Another area we would further our research on is materials selection. There may be lighter materials available which would improve our thrust to weight ratio, granting us faster flight. There may also be more inexpensive materials so that we could build more planes (in the event of destruction or increased demand). Lastly there could be a better way to manufacture and assemble it so that it is easier to transport and operate. At full scale this could very well change how we survey and service power lines, especially in hard to reach places.
Figure 2- Pressure Plot at
40MPH and 5000ft
Figure 1- Velocity Plot at 40MPH and 5000ft