Technical Brief and Overview

Lehigh Hyperloop

Team Captain: Correll French

Executive Summary

Faster transportation is key to the advancement and forward progress of civilization.

This report describes and evaluates the Lehigh Hyperloop Team’s design of a Pod for

the SpaceX Hyperloop transportation system. Aiming to create a smooth, durable,

and cost effective pod, each subsystem was uniquely designed and integrated into the

overall project. Aerodynamic drag was minimized to optimize speed and acceleration.

To promote stability and safety, systems were designed to respond at high speed and

automatically to constant sensor input. To keep the project affordable, several

systems were custom designed from raw materials and parts. To accommodate all

passengers, accessibility and safety have been a major factor of the design effort

including a Handicap Accessibility System. Focusing on a smooth and comfortable

ride, the design’s focus has been to create a unique and optimal ride for all end users.

2

Contributors

Correll French*

IBE Finance and Electrical Engineer

Team Captain

Tech Tanasarnsopaporn*

Material Science

Lead Mechanical Engineer

Vincent Pileggi*

Mechanical Engineer

Levitation Lead

Devon Zeidler*

Electrical Engineer

Communications Lead

Andrew Culkin

Mechanical Engineer

Hull Sub-team

Evan Mehok*

IDEAS Mechanical Engineer

and Computer Science Engineer

Handicap Sub-team

Colin Bader*

Mechanical Engineer

Brakes Sub-team

David Brandt*

Electrical Engineer

Brakes Sub-team

Emily Porfiris

Mechanical Engineer

Hull Sub-team

Alex Ferencin

Physics

Fund-raising Committee

Kenny Edwards

Mechanical Engineer

Propulsion Sub-team

Seamus Cullinane*

Electrical Engineer

Lead Design Engineer

Christian Murphy*

Mechanical Engineer

Simulations Lead

Kyle Higgins

Physics

Outreach Lead

Kaity Hwang*

Mechanical Engineer

Propulsion Lead

Jacob Baer*

Civil Engineer

Propulsion Sub-team

Zhoujie Ji

IBE Mechanical Engineer

and Mechanical Engineer

Levitation Sub-team

Kyle Leonard

Electrical Engineer

Communications Sub-team

Joseph McDonough

IBE Electrical Engineer and Finance

Logistics Committee

Zack Fisher

Mechanical Engineer

Hull Sub-team

Peter Nguyen*

IDEAS Mechanical Engineer

and Product Design

Hull Sub-team

* - Denotes Technical Brief

and Overview Co-Authors

3

Contents

1.0 Hull……………………………………………………………………………………….6

1.1 Geometry………………………………………………………………...………6

1.2 Chassis and Body Structure…………………………….……………………8

1.3 Materials…………………………………………………………….…………12

1.4 Mass of Subsystems……………………………………..……………………13

1.5 Pressure Cavity and Bypass System………………………………………13

1.5.1 Pressure Cavity……………………………………………………….14

1.5.2 Bypass System………………………………………………………...15

2.0 Energy………………………………………………………………………………….16

2.1 Power…………………………………………………………………...………16

3.0 Propulsion……………………………………………………………...………………20

3.1 Hover Engines…………………………………………………………………20

3.2 Principles of Hover Engine Design……………………...…………………21

3.3 Producing Thrust………………………………………..……………………21

3.4 Wheels…………………………………………………………….……………23

3.5 Work…………………………………………………………………….………24

3.6 Maintenance………………………………………………………...…………24

4.0 Braking…………………………………………………………………………………25

4.1 Introduction……………………………………………………………………25

4.2 High Powered Braking…………………………………………….…………25

4.3 Hydraulic Brake Pad…………………………………………………………26

4.4 Rear and Diffuser Gradient Altering………………………………………27

4.5 Reverse Thrust in Confined Space…………………………………………27

5.0 Levitation………………………………………………………………………………29

5.1 Overview……………………………………………………………….………29

5.2 Compressor…………………………………………………………….………29

5.3 Air Bearings……………………………………………………………...……30

4

6.0 Communications & Sensors…………………………………………………………32

6.1 Sensors…………………………………………………………………………32

6.2 Communications………………………………………………………………32

6.3 Navigation………………………………………………………..……………33

6.4 Sensor Placement………………………………………..……………………33

7.0 Safety………………………………………………………………………………...…35

7.1 Safety Features…………………………………………………………….…35

7.2 All-Stop Command……………………………………………………………36

7.3 Stored Energy…………………………………………………………………36

7.4 Hazardous Materials…………………………………………………………36

8.0 Handicap Accessibility…………………………………………………….…………37

8.1 Application……………………………………………………………..………37

8.2 Design………………………………………………………………..…………37

8.3 Parts and Cost……………………………………………………...…………39

9.0 Scalability………………………………………………………………...……………40

9.1 Extension of Passenger Compartments………………………...…………40

9.2 Maintenance……………………………………………………………...……41

9.3 Cost of Production……………………………………………………….……41

9.4 Performance……………………………………………………………………41

10.0 Simulations…………………………………………………………….………………43

10.1 Trajectory………………………………………………………………………43

10.2 Aerodynamics……………………………………………………………….…44

10.3 Thermal………………………………………………………………………...46

10.4 Random Vibration………………………………………………………….…48

10.5 Vacuum Compatibility……………………………………………….………49

11.0 Financial Analysis……………………………………………………………………50

11.1 Cost Breakdown………………………………………………………………50

11.2 Bill of Materials………………………………………………………….……51

11.3 Total Cost………………………………………………………………………52

11.4 Fundraising……………………………………………………………………53

5

12.0 Logistics………………………………………………………………..………………55

12.1 Pod Construction………………………………………………...……………55

12.2 Production Schedule………………………………………….………………56

12.3 Pod Testing………………………………………………….…………………57

12.4 Functional Tests………………………………………………………………57

12.5 Ready Checklists……………………………...………………………………58

12.6 Transportation of Pod to California………………………………..………59

6

Hull

Geometry

The external geometry of the Pod is undeniably the cornerstone in achieving

a system that maximizes speed and energy efficiency; the primary goals of the

Hyperloop Design Competition. As aerodynamic drag varies with the cube of

vehicle’s speed, the ability to reduce a small amount of drag coefficient may result

in a large difference in power consumption while increasing the maximum velocity

achievable.

The Pod is designed into three distinct sections: head, passenger

compartment, and tail. For scalability reasons, the passenger compartment section

is designed to be a straight cylindrical shape (see more in Scalability). Therefore,

the design of head and tail sections directly contributes to most of the aerodynamic

drag and downforce onto the system. Per the design criteria established by the

SpaceX Hyperloop Competition, the size of the tube (70.6” diameter) creates another

challenge to reducing the drag. As the size of the passenger compartment – largest

portion of the Pod – is set at 31.5 x 35.4 x 33.5 inches (Width x Length x Height),

the geometry of the prototype hull must meet this requirement to accommodate the

crash test dummy being provided. From there, to optimize the pressure drag of the

Pod, the head section is shaped into a smaller area. The frontal area is designed

based on a toroidal hybrid shape. This results in the ease of air flow along the side

of the Pod. The tail section is also concave to reduce detachment drag. Along the

side and bottom of the Pod, there are diffuser tracks which enable the control of air

flow along the Pod resulting inless turbulence. These designs were achieved

through various theoretical and numerical analyses, creating an optimum design.

7

Diagram: 2-Dimensional design CFD velocity field

To avoid air choke at low travel speed due to the suction of the levitation

system, cost and energy effectiveness at high speed travel, the air intake area is

designed to cover approximately 40% of the total frontal area. This design also

allows an adequate portion of the air in the tube to flow to the side and above the

Pod reducing detachment drag at the rear. Furthermore, to prevent the effect on

overall aerodynamics due to the Kantrowitz Limit with the suction system and the

limitation of the plug fan, the gradient of the frontal area of the Pod is designed to

slope upward at the maximum allowable angle. This allows excess air to flow out to

the rear easily, raising the maximum travel speed.

Diagram: Exterior-front view Diagram: Exterior- back view

8

The exterior of the Pod has the maximum dimension of 3.05 x 10.85 x 3.88 ft

(Width x Length x Height). The detailed dimension of the Pod is as follow:

Diagram: Pod exterior dimension (expressed in millimeters)

Chassis and Body structure

The chassis serves as a vehicle skeleton to support the Pod’s weight, frontal

air pressure while moving at high speed, and the forces due to high acceleration.

The chassis design is inspired by monocoque construction where the frame is built

as a single-shell structure. This provides a strong support to the Pod while reduces

the weight of the Pod as compared to other types of structures. (Note: For the

Prototype Build Lehigh Hyperloop will be creating the Pod’s space frame using

aluminum alloy beams and bent alloy sheets as materials for cost efficiency).

9

Diagram: Chassis overview

Along with our unique safety features and emergency braking system,

several design concepts have been implemented to fulfill the extra structural

requirements for the Pod’s design. The design for the emergency braking system

has it attached to the lower floor of the Pod. When the braking system is deployed, a

great amount of force will act upon the parallel support structures. This will

prevent the collapse of the body frame while allowing the emergency braking

system to perform as needed. As modeled below, the chassis structure is well within

the transportation industry’s factor of safety.

Diagram: Emergency braking stress simulation

10

Diagram: Emergency braking factor of safety

While the chassis maintains the core structure, the body frame design also

facilitates the distribution of forces upon crashes. For head-on impact, the use of

lower density materials – i.e. aluminum alloy pipes – will result in small

deformation of the structure throughout the body frame to alleviate the impact.

This technique is widely used in modern vehicles and has proven performance. As

seen in the simulation below, the majority of the stress is distributed along the

chassis, head and tail structures, and the lower part of body frame minimizing the

effects on the passenger compartment.

11

Diagram:

Crash impact stress simulation (displacement scale exaggerated to aid view)

Diagram: Crash impact factor of safety

12

Materials

The core structural material to be used in the chassis is Aluminum Alloy

6063-T6 I-beam, which will support the Pod’s weight and withstand impacts.

Stringers made of Aluminum Alloy 6061-T6 square pipes will connect the U-shaped

chassis as extra support structures. In body frames and crumple zones, Aluminum

2024 T-6 square pipes will be used. The material’s strength properties will maintain

the structure and withstand frontal pressure, and will allow for the adequate

distribution of force for safety. The frame structures will be welded; then, the body

metal sheets will be riveted onto the frame. While there are several components at

the lower part of the Pod, the diffusers are designed to be flat surface to reduce

aerodynamic drag. There are gaps designed between the floor and equipment such

as propulsion motors. These gaps are intentional allowing a certain degree of

movement to the equipment.

To allow easier mounting of equipment onto the interior structure, we will

use honeycomb carbon fiber and metal sheets to create flat surfaces inside the Pod.

The interior flooring will be attached on top of chassis stringer.

Diagram:

Interior carbon fiber flooring technology is widely used in aircraft industry

13

Mass of subsystems

The total mass of the Pod is estimated at 1,250 kg. The table below shows the

breakdown of the sub-system weight. Sub-components are positioned in order to

distribute the weight of the Pod and center of gravity at the middle of the Pod and

8” from the Pod floor. This low center of mass minimizes the torque acting on the

system and prevents disturbance to the weight distribution system.

Team Mass (kg)

Hull 110

Propulsion (service) 120

Propulsion (operation) 70

Energy 400

Communications 5

Sensors 5

Levitation 300

Air pump 50

Total 1,060

Dummy Seat 20

Robotic Lift 100

Dummy 70

Total w/ extra 1,250

Table: Breakdown of subsystem weight

Pressure Cavity and Bypass System

While the hull exterior design minimizes the aerodynamic drag of the Pod,

the small ratio of cross-section tube and impact area creates a limitation for top

travel speed. In order to reduce the frontal pressure drag, a bypass system is

14

created. Alongside the bypass system, a pressure cavity is designed to aid and be

integrated with the levitation system’s compressor air intake.

Pressure Cavity

On the front of the Pod is mounted a durable, high pressure and high flow

rate fan that induces differential pressure in the front cavity. Since the compressor

can only operate in certain pressure conditions, this cavity sets a suitable

environment for the compressor to work while lowering the pressure formed in front

of the Pod, resulting in less pressure drag. Within the pressure cavity, there is a

vent which acts as the pressure regulator. At low travel speed, there is low frontal

pressure in front of the Pod. The vent can be closed to allow the cavity pressure to

build up and create suitable conditions for the compressor. At higher speed, there is

higher frontal pressure and inlet flow than what the compressor requires, for which

the vent can be opened to relieve the high pressure and flow from the cavity.

Diagram: Pressure cavity and vent setup

15

Bypass system

The excess flow from the pressure cavity and the remaining pressurized air

from the compressor will be released through the nozzle at the back of the Pod. As

the resulting air flow has high flow rate with higher pressure than the tube’s static

pressure, this will act as a secondary force to propel the Pod. Air flow from the vent

is induced by low pressure created by the two fans positioned at the back of the Pod.

The flow will be circulating through the internal system to provide convection

cooling and maintain temperature for the working conditions of the compressor and

other internal components.

For cost efficiency, a commercial plug fan of 128,000 cfm will be used as the

suction unit. This type of blower cannot account for all portions of frontal air flow

needed to be bypassed. Because of this limitation of the suction system at subsonic

speed, a considerable portion of the air flow is unaccountable. For large scale

production, more suitable alternatives to the plug fan are discussed in the

Scalability section.

16

Energy:

Power

Subsystem Amperage Volts

Communications(Computer) <5A 120V

Communications(Embedded

Systems) <1A 12V

Levitation 100A 240V

Propulsion 400A(40A per

motor) 12V

Total 122.5A 240V

Table: Estimated Energy Requirements

Due to high voltage and amperage requirements for levitation, lithium ion

batteries have been selected as the power source for the Pod design. While a

hydrogen fuel cell could provide a great amount of power, the size of a hydrogen fuel

cell large enough to release the required high amperage would be the size of the pod

itself and too large to be efficient. A gasoline powered engine/generator is not an

option due to sustainability and hazardous material usage. It has therefore been

determined, modeling a solution taken from the Tesla Model S battery, a large

battery using smaller commodity batteries would be used.

A 18650 battery size with 9800mAh's and 3.7V was found to be a cost

effective battery at only $1.32 per battery while also providing enough capacity and

normalized voltage. To reach the capacity and voltage needed, we will be using

battery modules that consist of 50 batteries in parallel. This produces a module that

has a capacity of 490Ah and a voltage of 3.7V. We will then combine seven modules

in series to produce larger modules of 490Ah and 22.2V. Eleven of these larger

modules are then wired in series to produce a battery of 490Ah and 244.2V

17

achieving the desired energy system. This equates to 3,300 of the smaller

commodity batteries. With this setup, if the Pod draws current at .25C, it will be

able to achieve the full 122.5A required to run at full capacity. To organize the

batteries the Pod will be made using 18650 battery brackets as shown below. To

handle charging the team will utilize a power charging module (PCM) that is rated

at 150A, 22.2V and 6 cells. This was chosen for its amperage rating as well as its

cell rating. With large modules consisting of 6 smaller “cells” this has been

determined to be optimum for the Pod’s battery design. It has been designed to

balance the batteries while charging, providing system safety and protecting the

batteries from over drawing, over charging, and short circuits.

Part Link to Part Price per Unit(USD) Quantity Total

cost(USD)

18650 Battery http://goo.gl/Q2Cr1

N

$1.32 3000 $3,960.00

Battery Protection

circuit

http://goo.gl/7hhdc

q $50.00 10 $500.00

Battery Spacers size

3(10 pack)

http://goo.gl/4nvdF

B

$3.00 132 $360.00

Battery Spacers size 2

(10 pack)

http://goo.gl/ws8V1

9

$2.00 132 $240.00

Table: Battery Module cost breakdown

18

Diagram: 3D rendering of module

Diagram: Module side view

19

Diagram: Module Top View

Picture: Power Charging Module

20

Propulsion

Hover Engines

Arx Pax announced early in the competition that they would be developing

and selling their hover engine to teams. The Lehigh Hyperloop team has

determined that levitation of the Pod is not feasible with the aforementioned hover

engines as it would require 25-30 of them.

The air levitation system designed by the team allows the Pod to move freely

with minimal friction as discussed further in the Levitation section. In conjunction

with the designed levitation system, custom designed and built hover engines will

be utilized to propel the pod. The Lehigh team has custom designed a hover engine

of larger diameter and magnetic power to produce the required propulsion. Utilizing

the custom design, the budgeted cost is $7,154.08 total for 10 hover engines.

Equivalent cost for 10 Arx Pax hover engines has been estimated to be $48,500.

Due to the significant cost savings, the team has elected to utilize custom designed

hover engines in their Pod’s design.

Custom Hover Engine Parts Cost/Part # of Parts Total Cost

Motors $27.99 10 $279.90

Magnets 1" $7.19 360 $2,588.40

Magnets .5" $1.14 1800 $2,052.00

Magnets .25" $0.22 1800 $396.00

Motor controllers $89.99 10 $899.90

Metal (Aluminum) $245.96 3 $737.88

Shipping (Metal) $200.00 1 $200.00

Total $7,154.08

Table: Hover motor cost breakdown

21

Principles of Hover Engine Design

The foundation of the hover engine is Lenz's Law; by moving a magnet over a

conducting surface a repelling magnetic force is generated. Lenz’s Law may be

observed when a magnet is dropped down a copper tube; the magnet drops through

the tube slower than a non-magnetic material. While Lenz's Law does produce a

repelling force, it can be made greater by creating a stronger magnetic field. Thus, a

Halbach array, an arrangement of magnets which amplifies the magnetic field in a

unidirectional pattern, is utilized in the custom designed hover engine.

Picture: Halbach Array Comparison

Producing Thrust

The hover engines must be tilted to produce thrust, as shown in the Arx Pax

data sheet.

Picture: Arx Pax motor tilt diagram

22

Two screws from the two stepped motors connect to the top plate on the

magnetic disk. One motor will be programmed to move the screw up +0.17633

inches, and the other will be programmed to move down -0.17633 inches. This

results in a 10 degree tilt for the spinning disk. The left side will raise 1.56 inches,

and the right side would dip 1.56 inches.

Diagram: Hover motor depiction

Left Side

Right Side

Center of Tilt

23

Diagram: Circular Halbach array

Wheels

The main function for wheels on this pod is to provide ease of mobility at low

speeds; a range from 0 to 100 mph. A total of six polyurethane coated wheels will

support the pod, cargo and passengers weight during the initial stage of

acceleration and the final stage of deceleration.

24

Work

In addition to supplying Pod support at low speeds, the Pod’s wheels will be

required to steer and propel the Pod outside the tube system, to and from the

station. Since the Pod’s wheels main function is for use inside the tube, which will

be a near vacuum environment, a non-pneumatic tire was selected. The non-

pneumatic tires will provide greater support and less deflection and instability at

high rpm then the typically specified high speed roller coaster caster. Once the

wheels were selected, custom front and rear brackets were designed. The bracket

design of both systems utilizes trailing arm suspension principles, theoretically

limiting vibrations at high speed and increase stability. The front and middle

brackets will be mounted to a tapered roller bearing and then connected with a

bushing to a servo style motor. The steering is controlled in these motors, allowing

for high precision when needed. Additionally, in case of an emergency, the pod can

be decelerated by increasing the toe of the wheels and using the small rotor pad

system similar to that used in automobiles. The rear wheels will be hard mounted

to the deployment system on the Pod. They will not be free to rotate. Each wheel

will have a motor that will drive the pod forward and backward. The motor will be

permanently housed inside the Pod, the center of rotation for the deployment arm

will be in line with the motor shaft. A chain drive transmission will be used which

will lower gear ratio.

Road speed will be calculated to allow the motors to change speed when

cornering, preventing shutter and excessive wear.

Maintenance

Regular inspections of all the systems is crucial for the proper function and

safety associated to the Pod. Since these wheels will be driven on rough surfaces,

excessive wear will occur limiting the wheels lifetime and reliability requiring them

to be inspected frequently for repair, maintenance and replacement.

25

Braking System

Introduction

On top of reverse propulsion to decelerate the Pod, the braking system uses a

set of brake pads which grip the aluminum rail to slow the Pod. The system consists

of twelve Twiflex T2 brake calipers mounted along the sides of the central T-beam.

The system is pneumatically powered and theoretically capable of delivering a

combined force of up to 4050 N or 2.025 ms-2 of deceleration.

Diagram: Twiflex T2 brake calipers; T-Beam will be inserted in place of Brake Disc

High powered braking

In the case of collision or malfunction in the tube, high powered braking must

be available to ensure the safety of the passengers. Although the maximum

magnitude of acceleration/deceleration recorded by NASA is 83g, this emergency

braking will be within the non-harmful range of deceleration for the human body of

5g or just under 50 ms-2. The table below shows different braking distance and time

at various travel speeds if only the hydraulic brakes are used.

Travel Speed (ms-1) Travel Speed (mph)

Brake distance

(m)

Brake period

(s)

10 22.3694 1 0.2

25 55.9235 6.25 0.5

26

50 111.847 25 1

100 223.694 100 2

150 335.541 225 3

200 447.388 400 4

250 559.235 625 5

300 671.082 900 6

Table: Braking time and distance

Hydraulic Brake Pad

The emergency braking system consists of three sections: hydraulic brake

pads, rear flow manipulation, and reverse thrust.

First, the hydraulic brake pads are deployed while the levitation system

turned off. This will result in the normal force equal to the combination of weight

and downforce. As mentioned in body frame and chassis, the structure has been

designed to withstand this large amount of force without impacting the passenger

cabin. In order to avoid inducing excessive stress and heat onto the aluminum sub

track of the tube, the Pod uses ceramic brake pad as the braking material. Ceramic

brakes are proven to reduce wear on track and noise while maintaining durability

and power.

Diagram: Commercial ceramic brake pad

27

Rear and diffuser gradient altering

As the Pod is setup within the tube, many flow manipulation techniques can

be applied. At the rear, the diffuser and back covers will be expanded. The small

change in diffuser gradient will result in large increase in detachment drag at the

rear.

Diagram:

Rear expanded and diffuser concaves into the pod can significantly change

detachment drag.

Reverse Thrust in Confined Space

Another important mechanism in flow manipulation lies in the concept of

reverse thrust at the side of the pod. While the levitation system is turned off, the

suction system and pressure cavity are still active at a lower rate. This allows the

Pod to produce pressurized air using the compressor; the 55 CFM output at 8 bar is

adequate for this application. The mechanism is composed of two layers of reverse

thrust nozzles installed at each side of the Pod. This mechanism allows for the

simulation of the abrupt change in the Kantrowitz Limit, and ultimately reduces

travel speed to levels significantly below subsonic speed. According to the

simulation, this mechanism increased total drag by at least three times the drag

without reverse thrust.

28

Diagram: Reverse thrust flow streamline

Diagram: Reverse thrust flow arrow vectors

29

Levitation

Overview

In order to eliminate friction between the Pod and the ground, the Pod must

levitate. To accomplish this, magnetic levitation, compressed air, or a combination

of the two must be utilized. The Lehigh Hyperloop design employs compressed air

as the main form of levitation; the main source of which is an Ingersoll-Rand rotary

screw compressor. Although the Pod will be equipped with hover motors that could

assist in levitation, they will be reserved mainly for propulsion. In order to produce

lift, the compressor will feed air to four air bearings provided by Airfloat, a division

of Align Production Systems.

Compressor

The compressor creates a continuous flow which allows the air bearings to

receive steady air flow without the need to store a tank of compressed air within the

Pod. Rotary screw compressors also offer advantages to a Pod of this size that are

not offered by other types of compressors, such as an axial compressor. Rotary screw

compressors are typically smaller and lighter than other continuous flow

compressors. This particular model is also entirely electrically powered. Since there

is no need for fuel, the entire Pod can be powered via lithium ion batteries.

Eliminating the need for fuel is also beneficial since there is no need for a fuel tank

which reduces the Pod’s overall weight and eliminates the risks associated with

combustible materials. The compressor’s internal assembly will be reverse

engineered, deconstructed and reassembled in a configuration that is more suitable

to the Pod’s design. The original assembly does not maximize the area it

encapsulates, leaving several large voids within the compressor. It also comes with

large side panels not necessary for this purpose. The new configuration should

effectively utilize the space available, allowing for the design of a more aerodynamic

30

Pod. The compressor should also be cooled more efficiently with the air intake at the

front of the Pod.

Frequency

(Hz)

Rated

Pressure

(barg / psig)

Nominal

Power

(kW / hp)

Flow

(m3min /

cfm)

Length

(cm /

in)

Width

(cm / in)

Height

(cm / in)

Weight

(kg/ lbs)

60 8.5 / 125 11 / 15 1.55 / 55

104 /

41 73 / 29 91 / 36

295 /

650

Table: Compressor Specifications Ingersoll Rand Model: UP6 15c-125

Air Bearings

Air bearings, pictured below, were selected for converting the compressed air

into lift due to their reliability and efficiency. Air bearings are a highly reliable,

proven technology. They have been tested, modified, and improved through years of

research and development. In addition to providing an effective and reliable

product, purchasing air bearings is cost effective and time efficient as no man hours

are being put into the creation of an alternative method of utilizing the compressed

air.

Through the purchase of a controller, also supplied by Airfloat, the pressure

and air flow rate provided to each air bearing will be individually controlled by the

onboard processors to maintain stability. This will control the pitch, yawl, and tilt of

the Pod. The compressor’s output is higher in pressure and flow rate than required

by the air bearings, so the system does not need to be operated at full power. The

power capacity of the selected compressor is designed to maintain proper output as

the tube pressure is reduced to operating conditions. Having influence over each air

bearing ensures that Airfloat’s maximum recommended pressure and flow rate are

not exceeded. Additionally, the controller allows the net flow to be redistributed to

the air bearings in order to counteract an unequal weight distribution within the

Pod. Counteracting an unequal weight distribution allows for stable acceleration

through the tube. All excess air flow emitted by the compressor will be channeled

31

outside of the Pod through a pipe system expanding from the controller. Being that

the payload capacity of the air bearings is approximately 4 times the weight of the

Pod, this system will adequately maintain suitable conditions for the air bearings

and allow the Pod, as well as its cargo, to move through the tube with minimal

resistance.

Picture: Airfloat Specifications

32

Communications and Sensors

Sensors

The sensors, listed below, are the peripheral devices needed to control and

monitor the Pod. They have been selected for their ability to remain reliable at the

conditions the Pod is expected to experience and for their compatibility with

Arduino microcontrollers. The sensor network will consist of temperature,

accelerometer, pressure, and vibration sensors situated around the Pod to allow for

environment monitoring. These sensors will be connected to one of 5 regional

Arduino microcontrollers to allow for communication with other systems and with a

main Zotac Nano receiving terminal.

Table: Component Costs

Communications

Communication between the sensor systems and the main computer will be

done over Wi-Fi. The selected Arduino Yun microcontroller and Zotac Nano have

Wi-Fi built in and will act as transceiver and receiver. Sensors will be

systematically polled and interact with the regional microcontrollers to which they

are attached. The Arduino will then communicate with the main computer over Wi-

Fi. Once the data from the sensors is received, it will be displayed on a graphical

user interface, analyzed, stored, and relayed to the user.

33

Navigation

Navigation will be handled by an Adafruit GPS and a NVIDIA video

processor. This GPS operates at a 10Hz updating rate, it will be efficient at keeping

track of the position of the Pod while it travels through the tube. The GPS will be

connected to an Arduino controller that will transmit the location over Wi-Fi to a

main external terminal. The NVIDIA video processor will analyze the external

features of the Pod determining how far the Pod has gone and how far it has to go.

The utilization of these two sensors will ensure that the Pod position can be

determined at any point in the tunnel, and will allow for the brakes to be activated

at the correct time.

Sensor Placement

The sensor placement diagram, shown below, illustrates the main areas of

the Pod that will need an Arduino microcontroller to connect sensors in that area.

The main sensor regions are the front, top, and rear of the Pod along with the cabin

and engine/compressor areas. These areas will have a regional Arduino that will

connect with the desired sensors for the area. The placement of these sensors will

allow for a view of the overall state of the Pod during operation. Sensor placement

will have to be taken into consideration during construction of the hull and during

placement of other subsystems to ensure accuracy and control.

34

Diagram: Sensor Map

35

Safety

Safety Features

The Pod is designed to run on internally stored power, however, should power

dissipate spontaneously or the Pod loses power, the wheels will automatically

deploy preventing collision with the bottom of the tube. The wheels will also have

an independent back up power supply to run their motors so that the Pod may be

removed from the tube under its own controls. As the Pod hull is designed using the

same materials as airplanes, in addition to the hull not being pressurized

differently from the tube, the Pod will be able to withstand rapid pressure changes.

In addition, the hull has been designed with a skeletal layer and supported

internally to strengthen it from collapsing due to explosive pressurization.

The fault tolerance of the Pod has been refined with the use of redundancies

for each system. For braking, the first stage is reversal of the propulsion motors

from acceleration to deceleration which has been projected to be able to maintain

3G acceleration and deceleration. If the Pod reaches a speed above expectations, the

rail brake pads will automatically be activated to increase friction near the end of

the tube. Finally, if the Pod will not stop under normal braking procedure, the on

board processor and controls will activate the All-Stop Command. With levitation,

current calculations show that the rotary compressor can create enough lift for the

Pod with less than 60% of its overall potential at high speeds. Even at lower speeds,

it will be able to lift the Pod with its full power. However, in case it cannot, the

wheels will not retract until the Pod sensors detect sustained lift. In terms of

energy, the projected power consumption compared to storage will be two hours of

battery life assuming normal operating parameters.

If the Pod becomes immovable due to failure in the propulsion system, the

wheels will be deployed and controlled manually with their independent power

supply and receiver. This may also be used in case the Pod breaks away from the

center rail or becomes wedged in the tube.

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All-Stop Command

Using onboard sensors, the speed and energy storage will be tracked such

that if there is a power failure or the Pod cannot safely stop under regular means

the All-Stop command will activate. The wheels will automatically deploy during a

loss of power and the brake pads on the rail and wheels will be engaged to increase

friction. These can also be activated manually at the control console in case of

unforeseen circumstances. In terms of trajectory, the safety parameters will be set

that the computer will assume a standard 3G deceleration using the propulsion

motors. If the Pod cannot stop within the remaining distance under these

parameters, the Pod will activate additional braking systems up to the All-Stop

Command.

Stored Energy

The sources of stored energy in the Pod include Lithium Ion batteries for

electrical energy and air tanks for pneumatics. These will be discharged and

emptied before transporting the Pod and during maintenance.

Hazardous Materials

The hazardous materials in the design of Lehigh Hyperloop are Lithium Ion

batteries and pneumatics which will be maintained in proper containers and

environments. As the battery modules will be custom built, the individual batteries

will be ordered in bulk and stored carefully for travel and construction. During

construction of the prototype, the hazardous materials will include welding and

metal work for which several team members are trained and certified.

37

Handicap Seat

Picture: Hull Cutaway to internal view

Application

As this Pod is being designed for mass public transit, by law and moral

standards, it is required to be handicap accessible. The Handicap Accessibility

System, as designed by Lehigh Hyperloop, allows for easy access into the Pod, by

any passenger, but especially by someone with a physical handicap or disability.

Design

This device utilizes a scissor lift, in combination with a linear-sliding tray on

guiderail tracks, to lift the floor up and out of the Pod so that it is level with the

38

ground. Attached to the lift is a single seat, which the passenger can easily step

into, or be placed into, depending upon their physical needs and conditions.

Picture: Handicap Seat 3D rendering

Picture: Scissor Lift CAD model

The design of the scissor lift will be strong and compact, while allowing the

seat to be lifted to an easily accessible height. The four motors and gearboxes

utilize chains to provide power to lift the applied weight, while remaining efficient.

The tray rests on top of carts, which are locked onto guiderails. There are two

levels of guiderails to maximize the distance of linear motion. Parallel to the

39

guiderail tracks are threaded rods. A single motor spins each rod, and the resulting

motion forces the threaded attachments on the carts to move the tray linearly to its

destination.

Picture: Guiderail CAD model

Parts and Cost (Estimated)

Item Price per Unit (USD) Quantity Total Cost (USD)

VersaPlanetary 1:1 Gearbox with 1/2" Hex Output $39.99 4 $159.96

VersaPLanetary 5:1 Gear Kit $14.99 4 $59.96

VersaPlanetary CIM Adaptor $4.99 4 $19.96

Bag Motor $24.99 4 $99.96

IVTAAN Linear Guide $73.22 4 $292.88

Aluminum Plate w/ 6061-T651 Mill Finish .5x28x48in $364.35 1 $364.35

1/2 in. x 10 ft. Threaded Electrical Support Rod $10.36 1 $10.36

Threaded Brackets around Cart $30.00 8 $240.00

VersaFrame 1" x 2" x 0.10" Pre-Drilled Tube Stock (59" length) $24.99 2 $49.98

Nuts $10.00 5 $50.00

Bolts $10.00 5 $50.00

WCP SS Gearbox

Base Options1 x WCP SS - Single Speed Base Kit

P/N: 217-3421 Gear Ratio Options1 x WCP SS - 50:24 Ratio Kit

P/N: 217-3624 Motor & Motor Controller Options3 x CIM Motor

P/N: 217-2000

Flanged Bearing - 13.75mm (1/2" ThunderHex) x 1.125" x 0.313" $3.99 50 $199.50

1/2" ThunderHex Stock (3 feet) $13.99 5 $69.95

Clamping Shaft Collar - 1/2" Hex ID $2.99 100 $299.00

8mm to 1/2" Hex Adapter $4.99 9 $44.91

2mm Key (5-pack) $2.99 3 $8.97

1/16" Acetal Spacer - 1/2" Hex (10-pack) $4.99 5 $24.95

1/8" Acetal Spacer - 1/2" Hex (10-pack) $4.99 5 $24.95

Power Distribution Panel $199.99 1 $199.99

Talon SRX $89.99 6 $539.94

#25 Roller Chain (10 feet) $9.99 2 $19.98

#25 Heavy Duty Master Link $2.49 5 $12.45

#25 Heavy Duty Half Link $2.49 5 $12.45

#25 Sprocket w/ Hub - 16t - 1/2" Round ID $6.99 6 $41.94

#25 Sprocket w/ Hub - 22t - 1/2" Hex ID $6.99 6 $41.94

VersaFrame 1" x 2" x 0.10" Pre-Drilled Tube Stock (59" length) $24.99 6 $149.94

VersaFrame 1" x 1" x 0.100" Pre-Drilled Tube Stock (59" length) $19.99 5 $99.95

Chair $300.00 1 $300.00

Total $4,561.86

$178.94 6 $1,073.64

Table: Handicap System cost breakdown

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Scalability

Extension of passenger compartments

Since the Pod is divided into three distinct sections (head, compartment, and

tail), our Pod design allows the compartments to be connected easily. To facilitate

movement during the turns, the pivot connectors can be placed after each segment

of the Hyperloop Pod. The choice of connector can be the modification of Scharf

coupler with additional buffer mounting as in the diagram below. This allows the

Pod to retain the strong chassis connection while absorbing and transferring forces

during braking. This type of coupler also has built-in electric coupler that allows

transmission between segments. The gap is estimated to take up less than 0.4 m in

length, and the connection has 100-160 degree of freedom. The space between each

segment will then be covered by smooth metal sheet cover to aid aerodynamics of

the Pod.

Note: The length of the segment can be varied from 3 meters or longer, and shall be

determined by the smallest turning radius of the path.

Diagram:

Siemen® Schwab coupling consists of coupling head, shock absorber and buffer

41

Maintenance

One significant loss of revenue and time in all vehicle systems lies in their

maintenance. Since the Pod is designed in distinct sections with each part able to be

disassembled and replaced, the maintenance is localized per section that requires

fixing unlike cars or airplanes. Such sections can be easily replaced and enable us to

reuse the vehicle parts that are still functional. The tail can be removed for

recharging the batteries and storage of luggage while the passenger compartment is

boarded. The front compartment can be checked and maintained separately.

Cost of Production

The major cost of building the Pod is the chassis and body frame. For small

scale production – as in this Hyperloop competition – the Pod will use aluminum

tubes and welding to make a space-frame chassis. However, the Pod structure has

been designed to be easily converted and compatible with pressed metal panels as

used in large scale production in the transportation industry. In terms of energy

storage, the current design will operate for up to two hours on service propulsion

and up to one hour on operational propulsion. Since the largest power consumption

comes from the levitation system, and is identical when scaled up, the power scaling

is linearly based on the amount of propulsion needed.

Performance: Competition versus Actual Production

As tube diameter will be larger than the competition’s specification, this will

further reduce the ratio of the cross-sectional area between Pod and tube. By

effectively increasing the Kantrowitz Limit of the Pod system, a higher top travel

speed can be achieved. In addition, a longer tube length will allow longer periods of

acceleration, resulting in higher terminal velocity. Also, a longer period of

deceleration can be employed which increases the safety factor for the passenger.

The frontal suction unit is another important and costly component of the

Pod. For cost efficiency and dimension limitation, the Pod model for competition

42

uses a plug fan with 128,000 CFM flow rate which cannot retrieve the total amount

of air required during subsonic flight. This causes high pressure drag at the front of

the Pod. However, in large scale production, the fan can be engineered and custom

made for a much higher flow rate with reduced size. This will increase the

operational range of the suction system; therefore the Pod will be able to achieve

higher top speed.

43

Simulations

Design Criteria:

Tube length = 1 mile = 1609 m

Max Pod Acceleration = 3.2 g = 3.2*9.81 = 31.39m/s^2

Non-Emergency Pod Deceleration = -3.2 g = -3.2*9.81 = -31.39m/s^2

Pusher Acceleration = 1.5 g for 1000 kg

= 1.2 g for 1500 kg

~1.35g for 1250 kg =13.23m.s^2

Maximum Displacement of Pusher = 800 ft = 243.84 m

Air Pressure = 8960 Pa

Air Density = .1065 kg/m^3

Air Viscosity = 1.89e-5 kg/m-s

Temperature = 310 K

---------------------------------------------------------------------------------------------------------------------

Trajectory

Calculating Minimum Speed and Travel Time:

The minimum speed and travel time was calculated with the assumption the

pusher is the only acceleration force with the hover engines used to maintain

optimum travel speed. Using maximum displacement of the pusher at 234.84m and

an acceleration of 13.23 m/s^2, the pod will achieve a maximum velocity of 80m/s.

The pod will then maintain its speed to a distance of 243m from the end of the tube.

The pod will then decelerate at the rate it was accelerated. Acceleration and

deceleration are calculated to be 6 seconds/phase, with a cruise time of 14 seconds.

The total travel time is estimated to be ~26 seconds.

Calculating Maximum Speed and Travel Time:

Assuming that the hover engines will accelerate the Pod at a rate that will

allow the Pod to achieve max speed equal to half that of a full scale pod, it will be

required to accelerate at 31.39 m/s^2 until the Pod reaches the tube’s mid-point.

44

The Pod will have reached its max speed of 224m/s at the half mile/tube mid-point.

Deceleration of the Pod will commence at the tube’s mid-point by applying the brake

systems and reversal of the hover engines output creating an equivalent

deceleration speed for travel to the tube’s terminus. Total travel time for the Lehigh

Hyperloop is calculated to be 14.28 seconds.

Graph: Trajectory Preditions

Aerodynamics

The simulation modeling performed by Lehigh Hyperloop revealed that at

224 m/s, the speed of the air flow would max out at 405.2 m/s (906.4 mph), passing

the speed of sound. It has been determined that achieving this air flow speed will

not generate significant problems with the Pod beyond slight instabilities. The Pod

itself will not travel at the speed of sound.

Table: ANSYS value Overview

45

Diagram: Iso Streamline Velocity (224 m/s)

Diagram: Zoomed Iso Streamline Velocity (224 m/s)

Diagram: Side Streamline Velocity (224 m/s)

The design team utilized the computer program Fluent to simulate and

record the Pod’s drag and lift. Utilizing drag and lift magnitudes, the coefficients of

drag and lift were calculated to be .481, .069. These numbers were obtained using

the calculation at 224 m/s for Iso Static Pressure. In addition to this, Fluent was

able to find Static and Total Pressure along with Turbulent Intensity.

46

Diagram: Iso Static Pressure (224 m/s)

Diagram: Iso Total Pressure (224 m/s)

Diagram: Iso Turbulent Intensity (224 m/s)

Thermal

Using the estimated top speed of 224 m/s and with lowered air pressure, the

flow of air does not pose a significant thermal threat to the Pod. However, the

California sun will have an effect on the thermal profile. Applying solar heat gains,

the tube will reach an approximate temperature of 310K. The thermal profile

47

transfers heat to the Pod and the areas that are most affected by the heat gain (i.e.

the base of the Pod which is directly in contact with the tube). Other regions of the

Pod, such as the top, will not be as greatly affected since it is not in direct contact

with the tube. The thermal profile also allowed for the determination of where the

Pod dissipates heat from (heat flux).

Diagram: Iso Thermal Profile

Diagram: Front Thermal Profile

Diagram: Iso Heat Flux

48

Random Vibration

A frequency of 320.24 Hz was selected to test the effects of random vibration

on the Pod. Using the Random Vibration analysis in ANSYS, the total X, Y, and Z-

Axis maximum and minimum deformation in meters was calculated. Along with

that, the stress and elastic strain on the Pod from that vibration were determined.

Deformation did not exceed more than 1.9353e-002 m in any direction positive or

negative.

Diagram: X-Axis Vibrations Deformation

Diagram: Y-Axis Vibrations Deformation

Diagram: Z-Axis Vibrations Deformation

49

Vacuum Compatibility

Due to its structural properties, Aluminum 2024 t-6 has been selected as the

material for use within the Hyperloop’s vacuum. With the addition of belt frames

and stringers, Aluminum 2024 t-6 is projected to maintain its structural integrity in

the tube’s low pressure environment.

50

Financial Analysis

Cost Breakdown

The costs have been categorized by team responsibilities. For the levitation

components, service wheels, air bearings, and rotary compressor, the team has

opted to use Commercial-Off-The-Shelf (COTS) components as they are more cost

and time effective, and they are modifiable after purchase. In addition, the team

currently does not have the skills, resources, or time to construct these from

scratch. These COTS components are designed to be molded to the project and can

be converted to our designs.

For custom builds, such as the Handicap Accessibility System (referred to as

Handicap Seat), the costs have been broken down further into a bill of materials

below. The custom builds were found to be more inexpensive to build from scratch

and fit the design better. The most noticeable cost saving came from the propulsion

motors which are almost 30% the price of buying the COTS. In the case of the

Handicap Seat, as this was an original idea, it has to be built from scratch and is

budgeted accordingly.

Table: Cost Breakdown

51

Bill of Materials

By analyzing the costs of materials, the team has been able to plan ahead

and know the materials that will be needed to successfully complete the build.

Because not all fastening and mounting materials were included, the cost

breakdown totals have been adjusted to account for missing materials, shipping,

and taxes.

The team is currently seeking sponsors in manufacturing and production to

assist with specific part selection and purchasing. With additional sponsors, the

team feels confident in their ability to construct the full size prototype.

52

Table: Bill of Materials

Total Cost

The calculated cost for build is $42,394.05 which includes some adjustments

for taxes and shipping. Including contingency for any design changes and material

cost inflation, we have calculated a budget cost of $45,000. An additional $15,000 of

53

expenses is anticipated for equipment, tools, testing, and shipping the Pod to

California.

The total project budget is an estimated $60,000.

Fundraising

Costs not anticipated and/or covered by sponsors, the team has taken and

will continue to make efforts to raise additional funds through their own endeavors.

These currently include T-Shirt sales and a crowd funding site run through Lehigh

University (See pictures below).

To date, the team has raised approximately $3500 which has been allocated

to travel expenses and materials for the Design Weekend being held at Texas A&M.

The team is actively seeking corporate sponsors and have succeeded in being

sponsored by St. Onge Company from York, PA. Furthermore, talks with several

companies in the Bethlehem area are underway for additional corporate

sponsorships dependent on our performance at Design Weekend. After Design

Weekend, the team will obtain commitments from their corporate sponsors and

continue fundraising through Lehigh University and other sources to fully fund the

project.

Picture: Team T-Shirt

54

Picture: Lehigh Hyperloop Ignite

55

Logistics

Pod Construction

The Lehigh Hyperloop team has been given permission to access the

university’s metal and wood shops, and warehouse space for the fabrication and

assembly of parts and systems for the Pod Construction. Facilities for the build are

located on the Lehigh Campus in Bethlehem, PA. Although spatially adequate for

the build, the shops and warehouses may not have the necessary tools and

equipment required for a successful build. The team is researching what tools and

equipment they will have to purchase to properly outfit the workspace being

supplied by the school.

The assembling of parts and components will be completed at the space

referred to as Mountaintop. It is a large warehouse style building, pictured below,

available for prototyping and construction projects. Usually used for summer

projects, the team has received permission to use the space for construction and

testing of the Hyperloop Pod. Several members of the team are certified auto-

mechanics, builders, or manufacturers who can train the rest of the team and

supervise construction of the project.

Photo: Mountaintop Space

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Production Schedule

Currently, the production schedule, shown below, uses the assumption that

materials will not be available until the first week of March. The time waiting for

shipments of materials will be utilized for coding, material prepping, and controls.

These task can be started immediately and certain materials should arrive quicker

than others. We feel using this later date of March 7th accounts for any

uncertainties in delivery and allows for more delays should they occur.

Additionally, without knowing which days will be available to work, the predictions

use a three workday per week schedule. With these assumptions, the estimated

finish date for construction would be April 16th approximately six weeks for build.

This allows for an additional six weeks of “extra” time should production run over

schedule with the goal of having the Pod construction completed by the last week of

May. With this buffer, there should be ample time as many of the systems will be

constructed simultaneously by our sub-teams.

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Diagram: Construction Gantt Chart

Pod Testing

Within the Mountaintop space, a test platform will be constructed to test the

levitation, service propulsion, and operational propulsion systems at slow speed.

For electrical systems and sensors, test environments will be arranged to confirm

the accuracy and frequency of measurements to further refine the fault tolerance of

the system. Although this does not allow for testing at full speed, it allows more

systems to be tested before the pod is transported to California for final testing and

build weekend.

Functional Tests

For Pod loading, the pod will be driven to the tube entrance under its own

service propulsion and enter by wheel if there is ramp access. If the platform is

58

raised, it will be picked up by the crane supplied by SpaceX. The full power up will

run with a preprogrammed diagnostic to confirm 2-way communication. The

simulations and predictions for levitation currently show the Pod can levitate at

regular air pressure, so test A will be run by the control console. After entering the

tube, the second communications test will be performed by user input to the console.

Finally, at vacuum pressure, the final test can be performed, however, the wheels

will remain deployed in case the pod cannot levitate while stationary at reduced

pressure. Once the pod has levitated, the wheels will retract similar to an air plane.

These initial tests will be performed on internal battery charge. At the end of the

tube, the systems will be powered down and the wheels will be engaged by the

control console to remove the Pod from the tube. The end diagnostic will confirm

that the pneumatics are discharged, rotary compressor is off and discharged, and

the operational propulsion motors are disengaged. The Pod will then be driven out

and away if the platform is not raised. If it is, the crane will be used to place it on

the road or access path and driven back to storage.

Ready Checklists

Once 2-way communications have been confirmed, the subsystems will be

started one at a time to confirm they are operational while the rail brake is

engaged. The pod may be unable to hover at vacuum pressure and may need

wheels to remain engaged up to required speed. Confirm by sensor that the pusher

is in contact with the interface to prevent damage. Finally, once all systems are

confirmed, disengage the rail brake and prepare for launch.

At the end of the tube, pneumatics and the rotary compressor will be

discharged and disengaged while the Rail brake remains engaged. Wheels will be

confirmed to be locked and engaged for service propulsion before communications

confirms the all-clear. Finally, the rail brake will be disengaged and the Pod will be

free to drive out of the tube.

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Diagram: Ready checklists

Transportation of Pod to California

Within the Mountaintop space, there will be access to cranes and delivery

docks which will be used to load the Pod onto a truck if it cannot be driven on. The

wheels will be locked and strapped down to be transportated to California. Current

estimates have the cost of transportation being at $5,000. During transportation all

batteries and pneumatics will be empty if they must remain in the Pod and will be

trasported with care. Upon arrival, it will be driven or craned off the truck and

recharged for driving to the staging area.