hovercraft body and frame - uc drc home

HOVERCRAFT: BODY AND FRAME

A thesis submitted to the

Faculty of the Mechanical Engineering Technology Program

of the University of Cincinnati

in partial fulfillment of the

requirements for the degree of

Bachelor of Science

in Mechanical Engineering Technology

at the College of Engineering & Applied Science

by

JEREMY SIDERITS

Bachelor of Science University of Cincinnati

May 2011

Faculty Advisor: Ahmed Elgafy, PhD

ii

TABLE OF CONTENTS

HOVERCRAFT: BODY AND FRAME .................................................................................. 1

TABLE OF CONTENTS .......................................................................................................... II

LIST OF FIGURES ................................................................................................................ III

LIST OF TABLES .................................................................................................................. III

ABSTRACT ............................................................................................................................ IV

PROBLEM STATEMENT AND RESEARCH ....................................................................... 1

PROBLEM STATEMENT AND BACKGROUND ........................................................................................................ 1 PRODUCT RESEARCH .......................................................................................................................................... 1 CUSTOMER FEEDBACK ....................................................................................................................................... 3 NEED IDENTIFICATION ........................................................................................................................................ 4 PRODUCT OBJECTIVES ........................................................................................................................................ 6

CONCEPT DESIGN AND SELECTION ................................................................................ 8

FRAME DESIGN ................................................................................................................................................... 8 SHELL DESIGN .................................................................................................................................................... 9

CONCEPT DESIGN AND CALCULATIONS ..................................................................... 10

BOTTOM HULL DESIGN .................................................................................................................................... 10 FLOOR DESIGN ................................................................................................................................................. 11 RIB DESIGN ...................................................................................................................................................... 12 STRINGER DESIGN ............................................................................................................................................ 13 URETHANE CORE .............................................................................................................................................. 13 TOTAL BUOYANCY ........................................................................................................................................... 15

FABRICATION AND ASSEMBLY ...................................................................................... 15

RIBS AND STRINGERS ....................................................................................................................................... 15 FOAM ............................................................................................................................................................... 17 HULL ................................................................................................................................................................ 17

TESTING ................................................................................................................................ 18

TESTING METHODS .......................................................................................................................................... 18 TESTING RESULTS ............................................................................................................................................ 18

PROJECT MANAGEMENT .................................................................................................. 18

SCHEDULE ........................................................................................................................................................ 18 PRELIMINARY BUDGET ..................................................................................................................................... 19 ACTUAL BUDGET ............................................................................................................................................. 19

REFERENCES ....................................................................................................................... 20

APPENDIX A - RESEARCH ................................................................................................... 1

APPENDIX B – SURVEY RESULTS ..................................................................................... 1

APPENDIX C – QFD ............................................................................................................... 1

APPENDIX D – SCHEDULE AND BUDGET ....................................................................... 1

APPENDIX E – MATERIALS AND PARTS LIST ................................................................ 3

iii

LIST OF FIGURES Figure 1: UH-10F Entry Level .................................................................................................. 1

Figure 2: Neoteric Hovertrek .................................................................................................... 2

Figure 3: UH-XRW Hoverwing................................................................................................ 2

Figure 4 - Ribs and Stingers...................................................................................................... 8

Figure 5 - Plywood Shell .......................................................................................................... 9

Figure 6 - Full Hovercraft Assembly ...................................................................................... 10

Figure 7 - Urethane Core Capacity ......................................................................................... 14

Figure 8 - Ribs Assembled ...................................................................................................... 16

Figure 9 - Ribs and Stringers .................................................................................................. 16

Figure 10 - Styrofoam in Hull ................................................................................................. 17

LIST OF TABLES Table 1: Customer Importance 3

Table 2: Engineering Characteristics 4

Table 3: Customer Features 5

Table 4: Schedule 18

Table 5: Proposed Budget 19

iv

ABSTRACT

Hovercraft are relatively unknown to most of the general public. They have great

potential as recreational vehicles, yet many people don’t even know of their existence. A

hovercraft was constructed that could have the ability to appeal to the public as a form of

recreational transportation, a la motorcycles and jet skis.

By collecting customer feedback, different product objectives and design alternatives

were evaluated. A design was devised that would take into account important customer

features and result in a hovercraft that would appeal to a large number of people.

Materials were chosen that would provide a sturdy, light structure. All joints were

sealed, and all wood was primed and painted to prevent water damage. Heavy components,

such as the engine and fan, were securely bolted to the frame. Through careful design and the

proper selection of components, the hovercraft hull was built.

Hovercraft: Body and Frame Jeremy Siderits

1

PROBLEM STATEMENT AND RESEARCH

PROBLEM STATEMENT AND BACKGROUND

Vehicles are generally divided into three categories based on the terrain on which they travel:

land, water and air. Most vehicles are restricted to only one of these categories. There is one

vehicle, however, that works in two of these categories, specifically land and water. This is a

hovercraft (1).

While hovercrafts do exist, their lack of an effective braking system and poor

maneuverability have prevented them from widespread acceptance (2). In order to correct

these problems, the engineering principles of the combustion engine for power as well as

forward and reverse air propulsion for acceleration and deceleration will be applied. The

principles of lift, aerodynamics, and manufacturing will also be applied in order to design

and fabricate a fully functional hovercraft without the flaws mentioned above. This vehicle

will provide both recreation and practicality for emergency situations on any surface. It will

truly be an all-in-one vehicle that will not be limited by terrain like today’s popular vehicles.

The project will require 3 persons and be broken down as follows:

Body and Frame: Jeremy Siderits

Propulsion and Braking: David Louderback

Lift and Steering: Kelly Knapp

PRODUCT RESEARCH

A hovercraft is a vehicle that uses a lift fan to create an air cushion on which it glides

over a surface (2). A separate thrust fan propels the vehicle forward and rudders provide the

steering (1). Several manufacturers of hovercraft exist and they each offer a product with

different features. Figure 1 shows a UH-10F Entry Level Hovercraft (3). This can be built

from a kit designed by Universal Hovercraft. This is a good way for a first-timer to be

introduced to hovercraft building, but it has many limitations. It only seats one person. A

single 10 hp engine provides both the lift and the thrust, giving it a low top speed. It does not

have brakes or a reverse feature. Being so small, it is more sensitive to the terrain and could

be dangerous in a collision.

Figure 1: UH-10F Entry Level

A single engine

provides the lift

and the thrust


2

Figure 2 shows a Hovertrek, manufactured by Neoteric (4). These hovercraft are unique

because they feature reverse thrust buckets that are able to close behind the thrust fan and

redirect airflow towards the front on the craft, causing it to slow down or move in reverse.

Neoteric hovercraft are single engine vehicles. This makes them lighter, but some of the air

from the thrust fan must be diverted underneath the craft to provide lift, which slightly limits

the top speed. Additionally, they use 2-cycle engines which are noisy and less reliable than 4-

cycle engines.

Figure 2: Neoteric Hovertrek

Figure 3 shows the UH-19XRW Hoverwing, manufactured by Universal Hovercraft

(5). Most hovercraft fly one inch or less above the ground (6), but the Hoverwing has a

cruising altitude at 6 feet, and can even soar as high as 20 feet. This vehicle can provide

thrills that no other hovercraft can, but it is more dangerous. Because it flies so high off the

ground, it required a more enclosed cockpit. This detracts from the open-air powersport style.

Figure 3: UH-XRW Hoverwing

After the research was conducted the best features from each hovercraft were

determined. These features, as well as others that were deemed appropriate for a recreational

hovercraft, were put into a survey and given to potential customers. Their feedback was used

to aid in the designing of a new, better hovercraft.

Reverse thrust

buckets redirect

airflow towards the

front of the hovercraft

Wings

provide lift

Enclosed

cockpit


3

CUSTOMER FEEDBACK

An interview was conducted with an employee of a powersport retailer. It was

determined that the main reason people purchase such vehicles is for fun and enjoyment, as

well as transportation of loads (7). An interview with two shoppers at the same retailer

revealed that engine reliability is an important factor (8). After this information was gathered,

a phone interview was conducted with an employee of Universal Hovercraft which revealed

that 4-stroke engines are more reliable than 2-stroke for hovercraft, and bag skirts are more

customer friendly than finger skirts (9).

Six employees of Neoteric Hovercraft were willing to fill out a survey and provide their

professional input. The survey was also handed out to seven peers who were considering

buying a recreational vehicle. A total 13 responses were received. Table 1 shows a list of

customer features in order of importance.

Table 1: Customer Importance

Customer Importance

Feature Avg

Reliability 4.54

Durability 4.54

Maneuverability 4.31

Speed 4.23

Safety 4.15

Effective brakes 4.15

Cost 3.92

Ease of use 3.75

Appearance 3.62

Ability to travel in reverse 3.15

Low noise 2.92

Cargo space 2.23

Ability to tow skiers/tubers 2.00

This survey makes it clear that features such as reliability and durability are very

important to the customer in this type of vehicle, while cargo space and tow capability are

not important.


4

NEED IDENTIFICATION

A Quality Function Deployment chart was developed to get the relative weight percent.

Engineering characteristics were listed that would support each customer feature. Each

engineering characteristic was assigned a number depending on its relationship to a particular

customer feature. These numbers were used to determine the absolute and relative

importance for each engineering characteristic. Table 2 shows each individual engineering

characteristic in order of absolute importance.

Table 2: Engineering Characteristics

Abs.

Importance

Rel.

Importance

Proper tip speed 4.90 0.16

Hull constructed with fiberglass seamed marine grade

plywood 4.16 0.13

Reverse thrust buckets 3.83 0.12

Sturdy construction 3.57 0.11

4 cycle engine powered at 85% 2.28 0.07

Crash bumper 2.27 0.07

Emergency stop 1.96 0.06

Rearview mirrors 1.82 0.06

Screen to cover the fans 1.71 0.05

Aerodynamic design 1.06 0.03

Warning labels/fire extinguisher 1.03 0.03

Mufflers 0.95 0.03

Ability to seat 3 passengers 0.95 0.03

2 ft3 cargo space 0.60 0.02

Tow rope 0.55 0.02


5

Customer importance was factored into the calculation of relative weight. This is the

percent importance of each customer feature. Table 3 shows the customer features in order of

relative weight.

Table 3: Customer Features

Rel

ativ

e w

eight

Rel

ativ

e w

eight

%

Durability 0.11 11%

Reliability 0.11 11%

Maneuverability 0.11 11%

Speed 0.11 11%

Safety 0.10 10%

Effective brakes 0.10 10%

Cost 0.10 10%

Ability to travel in reverse 0.08 8%

Low noise 0.07 7%

Cargo space 0.06 6%

Ability to tow skiers/tubers 0.05 5%

According to the QFD durability, reliability, maneuverability, and speed are all equally

most important with 11%. The ability to tow skiers and tubers is the least important feature.

If this feature was to be achieved, the frame of the hovercraft would have to be greatly

reinforced, adding weight and cost. For these reasons this customer feature may be dropped

from the design.


6

PRODUCT OBJECTIVES

The following is a list of the product objectives. The customer features are broken up

into engineering characteristics and objectives. They are sorted in order of importance.

Reliability (11%):

1. A four cycle engine will be used, instead of the unreliable 2 cycle that is used on

many hovercraft.

2. All electrical connections will be soldered and then covered with heat wrap to ensure

no bare wires will be exposed to water and corrosion.

3. All fasteners will be fastened with locknuts and/or Loctite for sturdy construction.

4. Engine will be powered at 85% during normal operation in order to obtain longer

engine life.

Durability (11%):

1. A rubber crash bumper will be placed around the craft and attached to the exterior

frame.

2. The hull will be constructed using ½” marine grade plywood coated with an epoxy

primer and an enamel grade finish for waterproofing.

3. All seams will be joined by fiberglass for superior strength and waterproofing.

4. All metal used for engine mounts or frame support will be primed and painted to

prevent corrosion.

Speed (11%):

1. The craft will be designed to travel in excess of 40 mph on calm water.

2. Sloped shapes will be used to reduce drag.

Maneuverability (11%):

1. Reverse thrust buckets can be used in addition to the normal rudders to control the

movement of the craft.

2. A turning radius of zero is achievable with minimal thrust but increases with speed.

Safety (10%):

1. A screen will cover the thrust and lift fans.

2. Fan tip speed will be kept below the manufacturer’s maximum tip speed in order to

keep the fan blades from breaking and possibly injuring people.

3. Warning labels will be placed on:

a. Any electrical device to prevent shock

b. Around the fans to prevent injury

c. Near engines to prevent burns

4. A fire extinguisher will be placed on board in the event that the engine catches fire.

5. All other safety requirements will be upheld based on part manuals.


7

Effective braking system (10%):

1. The hovercraft will feature reverse thrust buckets that cause the hovercraft to reduce

speed.

2. Fifty percent of the thrust airflow will be redirected for braking allowing a

deceleration equal to one half of the acceleration rate.

3. An emergency stop feature will be used to cut power to the lift fan. Pads on the

bottom of the hull will prevent damage when this feature is used.

Cost (10%):

1. The hovercraft will be priced similar to an ATV or Jet Ski, around $10,000 new.

Ability to travel in reverse (8%):

1. The hovercraft will be equipped with reverse thrust buckets to allow the craft to travel

in reverse by pulling a lever.

Low noise (7%):

1. Normal operation will be at less than 85 decibels.

2. The engines will be equipped with mufflers.

3. The fan tip speed will be below the manufacturer’s maximum tip speed. This will

minimize excessive sound.

Cargo space (6%):

1. The design will allow at least 2 ft3 of cargo space, located under the seat or in the

front of the hull.

Ability to tow skiers/tubers (5%):

1. A tow rope will be able to be attached to the back of the craft.

2. In order to legally tow a skier, the craft will be able to seat 3 passengers (10). It will

have rearview mirrors so the operator can verify the safety of the skier.


8

CONCEPT DESIGN AND SELECTION

FRAME DESIGN

The frame will utilize a set of ribs and stringers, as seen in Figure 4. Seven ribs will be

constructed out of 2x2s and spaced 20.25 inches apart, center to center. Three stringers will

be placed 17.25 inches apart, center to center. This design allows for necessary strength to

support the plywood floor. The cavities in the frame will be filled with a urethane foam core,

which will provide buoyancy and additional strength.

Figure 4 - Ribs and Stingers


9

SHELL DESIGN

The shell will be constructed using marine grade plywood. It will be placed over the

frame and coated with a primer and enamel grade finish. The seams will be sealed with

fiberglass. The strength axis of the plywood will be placed perpendicular to the main

supports (the ribs), and the majority of stress will be applied perpendicular to the strength

axis. This will maximize the plywood’s strength potential. ¼” thick plywood will be used for

the bottom of the hull, which will have to withstand the air pressure. ½” thick plywood will

be used for the floor, which will have to withstand the weight of passengers and cargo. The

shell is shown in figure 5.

Figure 5 - Plywood Shell


10

CONCEPT DESIGN AND CALCULATIONS

The final 3D model for the hovercraft assembly can be seen in Figure 6 below.

Figure 6 - Full Hovercraft Assembly

BOTTOM HULL DESIGN

The first step in designing the hull was to determine the forces and pressure that would

be acting on it. The air pressure underneath the hull was known to be 15.7 psf. The bottom

panel of plywood would have to withstand this pressure. The position of the strength axis,

direction of applied stress, and support distance were used to select the proper stress

equations. The factors in the equations were found in various tables (11).


11

Equation 1 – Bending Stress

psfL

SFw b

b 0.305.20

10512012022

1

Equation 2 – Shear Stress

psfL

QlbFw s

s 14219

13520)/(20

2

Equation 3 – Deflection Due to Bending Stress

00709.150001743

75.20

1743

44

3

EI

Lb

Equation 4 – Deflection Due to Shear Stress

00057.150001270

195.120

1270

222

2

2

EI

LCts

Equation 5 – Stress Due to Deflection

psfL

wtotal

d 7.1600057.00709.

160/5.20160/

From the above equations, 16.7 psf is the lowest stress the ¼” plywood can withstand,

so it is the limiting factor. 16.7 psf > 15.7 psf. Because the limiting factor is greater than the

air pressure under the hull, the ¼” plywood will withstand the pressure.

FLOOR DESIGN

The next step was to design for the stress on the floor. The floor should be able to hold

900 lbs of weight, including passengers, engine, and cargo. This becomes 26.1 psf over the

area of the floor. ½” marine grade plywood will be used, so the equations were adjusted

accordingly.

Equation 6 – Bending Stress

psfL

SFw b

b 1235.20

43012012022

1

Equation 7 – Shear Stress

psfL

QlbFw s

s 32119

30520)/(20

2

Equation 8 – Bending Stiffness

000759.1400001743

75.20

1743

44

3

EI

Lb


12

Equation 9 – Shear Stiffness

000006.1400001270

195.120

1270

222

2

2

EI

LCts

Equation 10 – Stress Due to Deflection

psfL

wtotal

d 7.111000006.000759.

240/5.20240/

The lowest stress the ½” thick plywood can withstand is the bending stress of 123 psf.

This is greater than the estimated stress of 26.1 psf, so ½” marine grade plywood is safe to

use.

RIB DESIGN

The next step was to verify that 2x2s could provide the necessary support for the

plywood hull. Calculations were used to determine the safety of the ribs (12).

Equation 11 – Weight per rib

riblbrib

ininpsi

ribs

lbW /8.115

785.1109.

7

900

The weight per rib was used to find the maximum shear stress and maximum moment.

Equation 12 – Max Shear Stress

lbV 9.572/8.115max

Equation 13 – Max Moment

inlbinlbM *1129399.575.max

After finding the section modulus, the maximum stress could be determined.

Equation 14 – Section Modulus

333

125.13

5.1

3in

bS

Equation 15 – Max Stress

psiS

M1000

125.1

1129max

Pine will be used in the 2x2s. This has an ultimate strength su = 5800 psi. This gives a

safety factor N = 5.8.


13

STRINGER DESIGN

The next step was to determine the safety of the stringers. First, the weight per stringer

was determined. Then, the maximum shear stress and maximum moment were determined.

Equation 16 – Weight per stringer

stringerlbstringer

ininpsi

stringers

lbsW /283

1065.1109.

3

900

Equation 17 – Max Shear Stress

lbsV 5.1412/283max

Equation 18 – Max Moment

inlbinlbM *3750535.1415.max

The section modulus is the same as the ribs. Taking the section modulus and maximum

moment, it was possible to solve for the maximum stress.

Equation 19 – Max Stress

psiS

M3333

125.1

3750max

Factoring in pine’s ultimate strength of su = 5800 psi, this gives a safety factor of N =

1.74. This is not a cause for strong concern, however, because the additional rigidity

provided by the ribs, plywood, and urethane core will raise the amount of stress the stringers

will be able to withstand.

URETHANE CORE

An expanding urethane foam will be poured into the cavities between the ribs and

stringers, providing extra strength as well as buoyancy. Figure 7 shows the square cavities in

which the urethane will be placed, and then sandwiched inside the plywood hull assembly.


14

Figure 7 - Urethane Core Capacity

Knowing the dimensions of the cavities, as well as the dimension of the space in the air

duct that will be reserved for foam, it was possible to calculate the volume of urethane foam

that can be used.

Equation 20 – Volume of Hull Cavities

3

3

3

11.281728

15.10.160.19 ft

in

ftininin

Equation 21 – Volume of Duct Cavities

3

3

3

469.101728

140235.11402735. ft

in

ftinininininin

Equation 22 – Total Potential Foam Capacity 357.12469.1011.2 ft

Knowing that the selected urethane foam provides 60.5 lbs/ft3 of additional buoyancy

(13), it is possible to calculate the buoyancy provided by the foam.

Equation 23 – Total Foam Buoyancy

lbsftft

lb5.76057.125.60 3

3


15

TOTAL BUOYANCY

The hovercraft needs to have the ability to float on water without sinking. It is

important to verify that the expected weight can be held by the buoyancy. Knowing that 5

sheets of ¼” plywood and 1 sheet of ½” plywood will be used, as well as the buoyancy of

marine grade plywood (35 lbs/ft3) and the weight of water (62.5 lbs/ft

3), it is possible to

calculate the buoyancy provided by the plywood hull.

Equation 24 – Volume of Plywood

367.4)12

15.84()5

12

125.84( ft

in

ftftftft

in

ftinftft

Equation 25 – Total Buoyancy of Plywood

lbsft

lb

ft

lbft 4.128355.6267.4

33

3

Adding the buoyancy of plywood to the buoyancy of foam, the total buoyancy can be

obtained.

Equation 26 – Total Buoyancy

lbslbslbs 9.8885.7604.128

Equation 26 describes the extra buoyancy provided by the plywood and urethane, in

addition to the buoyancy needed to float an unloaded hull. In other words, it is the amount of

cargo the hovercraft can hold over water without sinking.

FABRICATION AND ASSEMBLY

RIBS AND STRINGERS

The ribs and stringers were cut from 2x2 Douglas fir. They were cut to the varying

lengths determined from the SolidWorks sketches. When it was necessary to make an angled

cut, an adjustable miter saw was used to achieve this.


16

Figure 8 - Ribs Assembled

They were assembled using impact drills to drive in the screws. Loctite PL Premium

Polyurethane Construction Adhesive was applied to each wood joint before it was screwed

together, ensuring a very strong bond. When all the ribs were assembled, they were attached

to the stringers, forming the basic skeletal structure for the hovercraft hull.

Figure 9 - Ribs and Stringers


17

FOAM

In order to increase buoyancy, 2 lb density urethane foam was purchased from US

Composites and poured into the ductwork within the hull. Styrofoam was placed in the empty

spaces between the ribs and stringers.

Figure 10 - Styrofoam in Hull

HULL

The outside skin for the hull was cut from ¼” marine grade plywood. A table saw was

used to cut compound angles, in order for the plywood to fit perfectly over the skeleton. ½”

thick marine grade plywood was used to provide extra strength for the floor of the hull. The

same construction adhesive was applied to the plywood before it was screwed onto the

frame, providing a bond that would not leak water and damage the structure of the craft.


18

TESTING

TESTING METHODS

As construction was carried out, the hovercraft was suspended over sawhorses. Large

components were attached to the hull, and team members were often inside the passenger

compartment. This is how it was determined that the hull could withstand the weight of all

passengers and cargo.

When the hovercraft is operable, a buoyancy test will be undertaken. One passenger will

take the craft to shallow water and turn off the engine. Weight will be added to the passenger

area until either the design weight is reached, or the craft sinks to an uncomfortable level.

TESTING RESULTS

The weight test was conducted successfully. The craft, fully loaded, would not bend

under its weight. The combination of ribs, stringers, urethane foam core, and plywood skin

proved to be rigid enough to withstand the design weight.

PROJECT MANAGEMENT

SCHEDULE

The first milestone on the schedule was the Proof of Design Contract, which occurred on

11/24/10. The last date is the due date of the final report, 5/30/11. Table 4 contains some key

dates of the schedule; the full schedule can be found in Appendix D.

Table 4: Schedule

Proof of Design Contract 11/24/2010

Design Freeze 1/31/2011

Oral Design Presentation 2/28/2011

Design Report 3/7/2011

Tech Expo 5/20/2011

Oral Final Presentation 5/23/2011

Final Report Due 5/30/2011


19

PRELIMINARY BUDGET

A preliminary budget was developed in order to provide and estimation of the costs of

this project. Table 4 contains the budget, with individual components condensed into the total

cost of each system.

Table 5: Proposed Budget

System Cost

Lift $ 525.00

Thrust $ 600.00

Body $ 520.00

Steering $ 150.00

Electrical $ 200.00

Misc. $ 375.00

Total $ 2,370.00

It was decided to switch from a 2-engine to a single engine craft. This will reduce the

total cost, as only one engine will need to be purchased. The drivetrain components were

approximated to cost $600. The original estimated price of the hull is believed to be an

underestimate. The new estimated total is $3750.

ACTUAL BUDGET

Sponsorship donations accounted for $5000. The team members split the remaining cost

of the craft, which was also $5000. The estimated cost for the team members was $3750; this

was an underestimate of $1250.


20

REFERENCES

1. Perozzo, James. Hovercrafting as a Hobby. Bend, OR : Maverick Publications, 2001.

2. Northern Hovercraft. FAQ'S. Nothern Hovercraft. [Online] Nothern Hovercraft. [Cited:

11 20, 2010.] http://www.northernhovercraft.com/faq.html.

3. Universal Hovercraft. UH-10F Entry Level Hovercraft. Universal Hovercraft. [Online]

Universal Hovercraft. [Cited: 09 29, 2010.]

http://www.hovercraft.com/content/index.php?main_page=index&cPath=33_40.

4. Neoteric Hovercraft. 4 Passenger Recreational Specifications. Neoteric Hovercraft.

[Online] Neoteric Hovercraft. [Cited: 09 20, 2010.]

http://neoterichovercraft.com/specifications/4Lspecifications.htm.

5. Universal Hovercraft. 19XRW Hoverwing. Universal Hovercraft. [Online] Universal

Hovercraft. [Cited: 09 29, 2010.]

http://www.hovercraft.com/content/index.php?main_page=index&cPath=2.

6. Fitzgerald, Christopher and Wilson, Robert. Light Hovercraft Design. Foley, AL : The

Hoverclub of America, Inc., 1995.

7. Baker, Larry and Kathleen. Power Sports Enthusiasts. Cincinnati, OH, 10 01, 2010.

8. Simons, Chuck. Power Sports Sales Specialist. Cincinnati, OH, 10 01, 2010.

9. Springer, Ryan. Hovercraft Manufacturer. Rockford, IL, 09 29, 2010.

10. Ohio Department of Natural Resources, Division of Watercraft. The legal

requirements of boating: towing a person with a boat or PWC legally. BOAT-ED. [Online]

Ohio Department of Natural Resources, Division of Watercraft, 04 02, 2010. [Cited: 09 29,

2010.] www.boat-ed.com/oh/course/p4-15_reqspectotowing.htm.

11. APA - The Engineered Wood Association. Panel Design Specification. [Online] 2008.

[Cited: January 20, 2011.]

http://www.apawood.org/pdfs/managed/D510.pdf?CFID=25720809&CFTOKEN=47538112.

12. Mott, Robert L. Machine Elements in Mechanical Design. Upper Saddle River : Pearson

Prentice Hall, 2004.

13. US Composites. 2 Part Liquid Expanding Urethane Foam. [Online] 2008. [Cited:

February 3, 2011.] http://www.shopmaninc.com/foam.html.

Appendix A1

APPENDIX A - RESEARCH

Problem:

Owners of recreational vehicles such as ATVs, boats, and jet-skis are limited to travel

depending on whether they are on land or water. The hovercraft is a recreational vehicle that

can travel on any type of surface including land or water. While several companies

manufacture hovercraft, they are very expensive and usually include minimal features. A

hovercraft will be developed that would entice the power-sports enthusiast by offering the

features of all the other recreational vehicles. This hovercraft will be a total replacement.

Also the hovercraft to be developed will be built for less than $10,000 in order to compete

against present-day recreational vehicles.

Closest MET Projects:

OCAS 1:4 Jet Propulsion Boat

Joseph Duffey, Douglas Weber, Adam Patterson, 1987

One-Man Propeller Driven Airboat

Sean Nguyen, 1990

These two projects are similar to a hovercraft in that they both use the propulsion of air to

move the craft, rather than using a propeller in the water. However, these two projects differ

from ours because they are still boats, and being so, they are limited to use only on water.

Our hover craft will float on a cushion of air and as a result, will be able to easily travel on

nearly any terrain, whether it is land or water.

Appendix A2

Interview Notes:

Interview with power sports sales specialist, Oct. 1, 2010

Chuck Simons (513-752-0088)

Beechmont Motorsports, 646 Mount Moriah Drive, Cincinnati, OH, 45245.

Sells recreational vehicles including ATVs, Jet-Skis, and Dirtbikes.

All vehicles offer excitement but are limited by either land or water.

Chuck stated that the reasons why people buy recreational vehicles are:

Fun and enjoyment

Hunting

Farm Help

Convenience (carrying big loads)

Features or specifics that most customers are interested in include:

Automatic Transmission

Fuel-Injected Engine

Speed

Noise Levels

Cargo area

Carrying racks (For ATVs)

Interview with power sports enthusiasts, Oct. 1, 2010

Larry and Kathleen Baker (did not want to give contact number)

Beechmont Motorsports, 646 Mount Moriah Drive, Cincinnati, OH, 45245.

Owners of an ATV and a Jetski.

Larry and Kathleen said that the newer engines are very electrical and their

brand new ATV and jet-ski models had broken down several times and were

difficult to repair. They stated they would never buy a newer model again and

that older style engines were more reliable and much simpler.

They stated that their jet-ski was fun because they could tow their children on a

tube. (In our research, we found that in the state of Ohio, a motorsports vehicle

is only capable to pull a third party if it is rated to carry at least three people

on-board and it has mirrors to see behind the vehicle).

Interview with hovercraft manufacturer, Sept. 29, 2010

Ryan Springer (815-963-1200)

Universal Hovercraft, 1218 Buchanan Street, Cincinnati, OH, 45245.

Ryan stated that:

The hovercraft’s hull should be slightly tapered and buoyant so that it floats in

water in case of engine failure.

Universal Hovercraft is proud that they only use four-stroke engines. A two-

stroke engine produces loud winding noise levels and they are less reliable.

A bag skirt is more customer-friendly since they are thicker than finger skirts

and repairing is easy to do in the field with scrap PVC coated nylon and skirt

glue. Also, the bottoms of the finger skirt deteriorate quickly since they are

typically made of thinner material.

Appendix A3

Related Products:

The UH-10F Entry Level Hovercraft is a great design for first time

builders, high school technology classes and home science projects.

First time builders and students get hands-on experience in

woodworking, fiberglass, small engines, propellers, as well as gaining

knowledge in engineering, aerodynamics and physics.

A single 10 hp Tecumseh horizontal shaft engine turns a two blade 36-

inch ducted propeller that provides both lift and thrust. This single

engine design is both simple and reliable, and has been successfully

built and flown by students in hundreds of schools and colleges

throughout the world. The 10F complies with the Hoverclub of America Entry Level racing requirements.

It's built from a foam and plywood sandwich construction. The

combination of these materials makes a low cost, high strength

composite structure that is un-sinkable.

Driving the craft is easy as it has only two controls; steering and

throttle. Slowly advancing the throttle will bring the craft up on

cushion. Adding a little more power accelerates the craft. Speed is

easily controlled by increasing or decreasing engine rpm. First time pilots can learn to operate the craft in a very short period of time.

The craft will operate on land, water, snow, ice, mud, parking lots,

football fields, ponds and rivers. Speed varies over each terrain.

Smoother terrain will allow the craft to achieve higher speeds while rough terrain will slow the craft.

The Hoverclub of America has designed a racing program specifically

for the 10F & 10F2 Entry Level Hovercraft. The program is designed

to allow close competition between individual competitors, High

Schools and Universities at a very affordable price. See Hoverclub of

America for more information.

Offered in a kit priced at $1,499

Very reasonable price

Price does not include wood,

hardware, upholstery, wire, or paint

costs

Only accommodates one person

Only one engine - limits power and

speed

Low HP

25 – 35 MPH

Travels on all surfaces

Very limited design

http://www.hovercraft.com/content/index.php?main_page=in

dex&cPath=33_40

9/29/10

UH-10F Hovercraft

http://www.hoverclubofamerica.org/

http://www.hoverclubofamerica.org/

http://www.hovercraft.com/content/index.php?main_page=index&cPath=33_40



Appendix A4

Neoteric is the original light hovercraft manufacturer and

the Hovertrek™ is the culmination of Neoteric’s 40 years

of experience in light hovercraft design, development and

engineering. Its aesthetically appealing design embodies

all the advantages and advances Neoteric has innovated:

side-by-side seating, fully enclosed cabin, highly

developed reverse thrust for braking and maneuverability,

more cockpit room, increased thrust and low weight.

Engineered to satisfy expectations and to give long life

and value for money, the Hovertrek™ is recognized as the

industry standard for recreational personal hovercraft.

4 person, 750 lb payload

60 mile range

45 mph max forward speed on calm water

25 mph max reverse speed on calm water

83 dB (A)

Reverse buckets offer braking

and reverse capabilities

Limited to max 2 foot waves

16.7% slope gradient max

Expensive – 20-30K depending

on options

http://neoterichovercraft.com/specifications/4L

specifications.htm 9/20/10 Hovertrek,

Neoterichovercraft.com, Neoteric Hovercraft

http://neoterichovercraft.com/specifications/4Lspecifications.htm

http://neoterichovercraft.com/specifications/4Lspecifications.htm

Appendix A5

Universal Hovercraft is proud to offer the UH-

19XRW Hoverwing™ ground-effect vehicle for

recreational, industrial, commercial, military sales.

It is available to our customers on a ready to run

turnkey basis. The Hoverwing™, designed as a

high performance hovercraft, is unique because of

the ability to add wings for flight in ground-effect.

Flying in ground-effect enables you to clear

obstacles and fly over rough water at speeds in

excess of 75 mph. Cruise altitude is 2 to 6 feet and

the craft can jump up to 20 feet to clear large

obstacles. Operating in ground-effect does not

require a pilot's license, and the craft is registered

as a boat which brings a wide range of new

opportunities to the commercial and tourism

industry.

Removing the wings from the Hoverwing™ takes

just 10 minutes. With the wings removed the

Hoverwing™ converts into Sport mode, a sleek

high performance hovercraft, able to carry 4 to 6

passengers into areas that can't be reached with

any other vehicle. The Hoverwing™ can be

configured in many different ways to

accommodate your passengers or equipment

needs.

Ability to “fly” at very low heights

Extremely expensive - $85K

Must have a skilled operator

Increased level of danger

Very high speeds necessary to fly

Large, open terrain needed to fly

http://www.hovercraft.com/content/index.ph

p?main_page=index&cPath=2 , 9/29/10,

19XRW Hoverwing, hovercraft.com,

Universal Hovercraft

http://www.hovercraft.com/content/index.php?main_page=index&cPath=2

http://www.hovercraft.com/content/index.php?main_page=index&cPath=2

Appendix B1

APPENDIX B – SURVEY RESULTS

HOVERCRAFT CUSTOMER SURVEY

Please fill out this survey so we can get a better understanding of what the public wants in a

hovercraft.

How important is each feature to you for the design of a recreational hovercraft?

Please circle the appropriate answer. 1 = low importance 5 = high importance

How much would you be willing to pay for this vehicle?

$1000-$2000 $2000-$5000(1) $5000-$10,000(3) $10,000-$15,000(6) $15,000+(3)

AVG Cost Range – High end of $5000 - $10000

Thank you for your time.

AVG

Safety 1 2 3(5) 4(1) 5(7) N/A 4.15

Durability 1 2 3(1) 4(4) 5(8) N/A 4.54

Reliability 1 2 3(1) 4(4) 5(8) N/A 4.54

Maneuverability 1 2 3(1) 4(7) 5(5) N/A 4.31

Effective brakes 1 2(1) 3(3) 4(2) 5(7) N/A 4.15

Ability to travel in

reverse 1 2(3) 3(6) 4(3) 5(1) N/A

3.15

Low noise 1(1) 2(5) 3(3) 4(2) 5(2) N/A 2.92

Cargo space 1(4) 2(4) 3(4) 4 5(1) N/A 2.23

Speed 1(1) 2(1) 3 4(3) 5(8) N/A 4.23

Ability to tow

skiers/tubers 1(6) 2(2) 3 4(4) 5 N/A

2.00

Cost 1(1) 2(1) 3(2) 4(3) 5(6) N/A 3.92

Appendix C1

APPENDIX C – QFD

Appendix C2

Hovercraft Product Objectives

The following is a list of product objectives and how they will be obtained or measured to ensure that the goals of the project

were met. The product objectives will focus on the various aspects of a hovercraft. The hovercraft is a recreational vehicle and will

be designed to provide safe enjoyment for its users.

Reliability (11%):

5. A four cycle engine will be used, instead of the unreliable 2 cycle that is used on many hovercraft.

6. All electrical connections will be soldered and then covered with heat wrap to ensure

no bare wires will be exposed to water and corrosion.

7. All fasteners will be fastened with locknuts and/or Loctite for sturdy construction.

8. Engine will be powered at 85% during normal operation in order to obtain longer engine life.

Durability (11%):

5. A rubber crash bumper will be placed around the craft and attached to the exterior frame.

6. The hull will be constructed using ½” marine grade plywood coated with an epoxy primer and an enamel grade finish for

waterproofing.

7. All seams will be joined by fiberglass for superior strength and waterproofing.

8. All metal used for engine mounts or frame support will be primed and painted to prevent corrosion.

Speed (11%):

3. The craft will be designed to travel in excess of 40 mph on calm water.

4. Sloped shapes will be used to reduce drag.

Maneuverability (11%):

3. Reverse thrust buckets can be used in addition to the normal rudders to control the movement of the craft.

4. A turning radius of zero is achievable with minimal thrust but increases with speed.

Appendix C3

Safety (10%):

6. A screen will cover the thrust and lift fans.

7. Fan tip speed will be kept below the manufacturer’s maximum tip speed in order to keep the fan blades from breaking and

possibly injuring people.

8. Warning labels will be placed on:

a. Any electrical device to prevent shock

b. Around the fans to prevent injury

c. Near engines to prevent burns

9. A fire extinguisher will be placed on board in the event that the engine catches fire.

10. All other safety requirements will be upheld based on part manuals.

Effective braking system (10%):

4. The hovercraft will feature reverse thrust buckets that cause the hovercraft to reduce speed.

5. Fifty percent of the thrust airflow will be redirected for braking allowing a deceleration equal to one half of the acceleration

rate.

6. An emergency stop feature will be used to cut power to the lift fan. Pads on the bottom of the hull will prevent damage

when this feature is used.

Cost (10%):

2. The hovercraft will be priced similar to an ATV or Jet Ski, around $10,000 new.

Ability to travel in reverse (8%):

2. The hovercraft will be equipped with reverse thrust buckets to allow the craft to travel in reverse by pulling a lever.

Low noise (7%):

4. Normal operation will be at less than 85 decibels.

5. The engines will be equipped with mufflers.

6. The fan tip speed will be below the manufacturer’s maximum tip speed. This will minimize excessive sound.

Appendix C4

Cargo space (6%):

2. The design will allow at least 2 ft3 of cargo space, located under the seat or in the front of the hull.

Ability to tow skiers/tubers (5%):

3. A tow rope will be able to be attached to the back of the craft.

4. In order to legally tow a skier, the craft will be able to seat 3 passengers.

5. It will have rearview mirrors so the operator can verify the safety of the skier.

Appendix D1

APPENDIX D – SCHEDULE AND BUDGET

Schedule:

Jeremy Siderits, Kelly Knapp, Dave Louderback Tasks in black text are equally shared by the group members DATE

11

/21

- 1

1/2

7

11

/28

-1

2/4

12

/5 -

12

/11

12

/12

- 1

2/1

8

12

/19

- 1

2/2

5

12

/26

- 1

/1

1/2

- 1

/8

1/9

- 1

/15

1/1

6 -

1/2

2

1/2

3 -

1/2

9

1/3

0 -

2/5

2/6

- 2

/12

2/1

3 -

2/1

9

2/2

0 -

2/2

6

2/2

7 -

3/5

3/6

- 3

/12

3/1

3 -

3/1

9

3/2

0 -

3/2

6

3/2

7 -

4/2

4/3

- 4

/9

4/1

0 -

4/1

6

4/1

7 -

4/2

3

4/2

4 -

4/3

0

5/1

- 5

/7

5/8

- 5

/14

5/1

5 -

5/2

1

5/2

2 -

5/2

8

5/2

9 -

6/4

TASK

Proof of design contract 24

Hovercraft concept development 6

Preliminary hovercraft design 31

19

Engine 13

15

Fans 20

29

Gearing (sizes, ratios, and type) 27

12

Lift system 3

19

Thrust system 10

19

Steering 17

19

Throttle and controls 24

19

Hull 31

19

Winter Break (CAD drawings only) 2

2

Long delivery components 31

31

Major Component Design freeze 31

31

Final hovercraft design 21

3

Hovercraft BOM 21

18

Order hovercraft components 28

18

Oral design presentation 28

3

Design report 7

18

Component fabrication 14

Assembly 9

Demo to advisor 9

Demo to faculty 16

Oral final presentation 23

Final report due 30

Appendix D2

Hovercraft Budget:

System Component Price

Lift Bag Skirt $125.00

Lift Engine $100.00

Lift Fan $250.00

Muffler $50.00

Thrust Thrust Engine $100.00

Thrust Fan $350.00

Belt System $50.00

Reverse Buckets $50.00

Muffler $50.00

Body 1/2" thick marine grade plywood $150.00

misc wood $100.00

Fiberglass and resin $125.00

In-line Seating $40.00

Paint $75.00

Warning Labels $10.00

Duct Screen $20.00

Steel Tube Donated

Steering Handlebars $100.00

Rudders $50.00

Electrical Temperature Gauge $25.00

Temperature Gauge $25.00

Tachometer $25.00

Tachometer $25.00

Battery $50.00

Alternator $50.00

Misc Misc parts and hardware $375.00

$2,370.00

Material used for the bottom of the hull

Handlebar system

Temperature guage for lift engine

Temperature guage for thrust engine

RPM guage for lift engine

RPM guage for thrust engine

Joint support and waterproofing material

Enamel based paint for superior protection

Keep hand away, hot, electrical hazard

Fabric and support for seating

Hovercraft Budget

4-stroke engine

Muffler system

Mult-blade fan

Rudder system

Belt and pulleys

Fabricated fiberglass shell

Material used for ribs and top of the hull

Description

Vinyl coated nylon fabric

4-stroke engine (Discounted)

Multi-blade fan

Muffler system

Wire sceen for fan protection

N/A

Tube stock for engine support

12v Battery

System to charge battery

Total

Appendix D3

APPENDIX E – MATERIALS AND PARTS LIST

5 sheets 4’x8’x1/4” marine grade plywood

1 sheet 4’x8’x1/2” marine grade plywood

2x2s, 125 linear feet, pine wood

2 lb density urethane foam, Part # FOAM-0216 from US Composites

Polyurethane rubber strip, Part # 8997K551 from McMaster-Carr

6-Gallon Attwood gas tank

2 gallons fiberglass resin

100 linear feet fiberglass mesh tape

1 gallon epoxy primer

1 gallon marine enamel paint

Wood screws

hovercraft body and frame - uc drc home

Documents