P14462: Tethered Glider

Systems Design

Table of Contents

Systems Design Review

System Design Review Presentation

See presentation notes in Planning & Execution

Created - 04 October 2013

Functional Decomposition

Functional Decomposition

Functional Decomposition

Created - 16 September 2013

Risk Assessment

Risk Assessment Spreadsheet

Created - 16 September 2013

Last Updated - 2 December 2013


This shows all the proposed production gliders available that fit our requirements.
List of possible gliders

List of possible gliders

Created - 23 September 2013

Concept Development (generation, improvement, selection)

Concept development was divided into two systems:

  1. Glider Concepts
  2. Measurement Concepts

Glider Concepts

Buy Glider

Pros Cons
  • Pre-engineered to fly
  • Can purchase spare parts
  • Fast shipping
  • Modifiable
  • Not guaranteed to fly with tether
  • Expensive (approx. $100-$150)
  • Limited modifications

For a list of proposed gliders for purchase, see the image in Benchmarking.

Build Glider

Pros Cons
  • Can optimize plane for tethered flight
  • Build spare parts
  • Resources available
  • Not guaranteed to fly
  • Requires time to build
  • Complex
  • Hard to balance
  • Could become expensive

There are tutorials online, specifically the YouTube channel Experimental Airlines. As per the tutorials, we can create custom and interchangeable wings, fuselages, rudders, etc. At $80-$100, costs are cheaper than buying a glider.

Added - 16 September 2013

Glider Concept Selection

Considering time constraints, lack of knowledge building RC gliders, implementing servos, and repeat-ability concerns, we decided to buy a glider. The two gliders we narrowed down to were the Bixler v1.1 and the Phoenix 2000.

Glider comparison

Glider comparison

Using the theoretical simulation we developed, we compared the tension each glider would generation in flight. The larger Phoenix flight generated more tension than the smaller Bixler (see plots below). Due to this and our budgetary constraints with the load cell, we chose the Bixler.

Glider tension comparison plots

Glider tension comparison plots

Created - 30 September 2013

Measurement Concepts

Force Gauge and Resistance Gyro

Schematic Pros Cons
public/SLDR_Documents/P14462 - ForceGauge_ResistanceGyro.png
  • Innovative
  • Expensive
  • Complex data analysis
  • Internal turbulence in the resistance gyro
  • Requires current line on tether
  • Difficult to calibrate and set up

Three 1-Axis Load Cells

Schematic Pros Cons

public/SLDR_Documents/P14462 - 3singleaxisloadcells.png

  • Can repair individual components
  • Accurate
  • Cheap components
  • Difficult to calibrate
  • Potential for noisy data

One 3-Axis Load Cell

Schematic Pros Cons

public/SLDR_Documents/P14462 - 3axisloadcell.png

  • Accurate
  • Pre-calibrated
  • Intuitive setup
  • Expensive
  • Inherent dead zones

IMU Board & 1-Axis Load Cell

Schematic Pros Cons

public/SLDR_Documents/P14462 - IMU_1axisloadcell.png

  • Provides accurate position and orientation data
  • Requires noise filtering
  • Difficult to calibrate
  • IMU system would be on the glider

Force Gauge and GPS

Schematic Pros Cons

public/SLDR_Documents/P14462 - ForceGauge_GPS.png

  • Digital data
  • Accurate force measurement
  • Expensive
  • GPS increases weight of glider
  • Difficult to calibrate
  • Difficult to set up
  • Inaccurate position

Two potentiometers and One 1-Axis Load Cell

Schematic Pros Cons

public/SLDR_Documents/P14462 - Potentiometers_1axisloadcell.png

  • Inexpensive
  • Accurate angles
  • Easily breakable
  • Requires precise machining

Base Station Concept Selection

We utilized a Pugh diagram to compare each design. See the Feasibility section for the Pugh diagram.

The top three designs are using three 1-axis load cells, the IMU with a 1-axis load cell, and two potentiometers with a 1-axis load cell.

Created - 16 September 2013

Last Updated - 30 September 2013


The first Pugh diagram used the Three 1-axis load cells design as the datum.
Three 1-axis load cells

Three 1-axis load cells

The second Pugh diagram used the as two potentiometers and one 1-axis load cell the datum.

two potentiometers and one 1-axis load cell

two potentiometers and one 1-axis load cell

Both options used a purchased plane. The first option used 3 single axis load cells and the second option used a single axis load cell and an IMU.

Ultimately, the one 3-axis load cell was ruled out due to cost. The IMU and load cell proved to be a concept that should be shelved for future iterations of the project. Because of this, the two potentiometers and one 1-axis load cell design was chosen as the base station.

Created - 16 September 2013

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