High Altitude Balloon Team
Department of Mechanical
and Materials Engineering
014 Russ Engineering Center
Wright State University
Dayton, OH 45435
February 22, 2011
Senior Design Class
Russ Engineering 148
Wright State University
Dayton, OH 45435
To whom it may concern,
Enclosed please find the outcome of the proposed ―Design and Launch of a Balloon Re-entry
Vehicle for Free Fall Experimentation‖. The team conducted a drag-based study of various
ballute shaped re-entry vehicles. The ballute design was tested in a high altitude free fall. This
study provides valuable information on the importance of shape in a re-entry vehicle, with the
possibility of the ballute design eliminating the need for a parachute. The study is intended to be
applied toward space vehicles such as a mars rover.
The team has received guidance on the project from Dr. Joseph C. Slater, a professor at Wright
State University. He has given approval on our experiment and believes it will be successful. The
control box design was tested in a launch conducted on April 30th and the total system was
launched on May 31th. If you have any questions or concerns, please contact us at Wright State
University High Altitude Balloon Team located at 014 Russ Center, Wright State University.
The team looks forward to your comments and approval.
Sincerely,
High Altitude Balloon Team
Eddie McGovern, Alleyce Watts, Jade O’Mara, Adam Blake, and Ryan Vogel
Design and Launch of a Balloon Re-entry Vehicle for Free Fall Experimentation
February 22, 2011
Jade O’Mara, Alleyce Watts, Ryan Vogel, Adam Blake, and Edward McGovern
Dr. Joseph C. Slater
ME 490, Mechanical Design 1, Winter 2011
Dr. Rory A. Roberts
Wright State University
High Altitude Balloon Laboratory
018 Russ Engineering Center Dayton, Ohio
Approval:
ABSTRACT
Funded by the National Science Foundation, the Wright State University High Altitude
Balloon team (WSU HAB) has had 17 successful launches and recoveries. Throughout these
tests, WSU has achieved in launching devices to heights of nearly 100,000 feet (40,000 ft above
regulated airspace) while conducting experiments containing temperature sensors, cameras,
video transmitters/recorders, actuation devices, etc. As a result of being nationally recognized
and containing an unlimited amount of funding, the WSU section can sponsor multiple groups
consisting of students from practically any engineering degree.
This quarter the HAB team focused on creating a scaled atmospheric re-entry ballute.
This vehicle was used to test and demonstrate the aerodynamic stability of various ballute shaped
designs for the ILC Dover for a Mars atmospheric decelerator according to certain regulations.
Design parameters included, but were not limited to: a maximum weight per unit of six pounds,
an altitude parachute deployment of 65,000 feet, and drag of 125 mph. The teams also worked
on the enhancement of launch methods as well as all faces of aerospace design. A
transmit/receive tower on top of the Russ Engineering Center was intended to be used for digital
control and communication with the balloon’s payload for an approximate 300 miles radius
around campus however, was unsuccessful. Nevertheless, electrical components were
contributed by an Electrical Engineering team group on the High Altitude Balloon Team and
placed in a control box to follow the ballute. By combining mechanical structures and electrical
devices, new ideals and objectives during this term will continue the efforts of Wright State
engineering students who have worked on the project over the past five years.
i
TABLE OF CONTENTS
1 Introduction ............................................................................................................................. 1
2
Design of Experimental Procedure .......................................................................................... 2
2.1
2.1.1
Ballute ....................................................................................................................... 6
2.1.2
Parachute ................................................................................................................... 7
2.1.3
Release Mechanism .................................................................................................. 9
2.2
3
Fabrication ........................................................................................................................ 3
Measurement and Testing .............................................................................................. 15
Results ................................................................................................................................... 20
3.1.1
Launch 18 – April 30th 2011 ................................................................................... 25
3.1.2
Launch 20 - May 31th 2011 ..................................................................................... 30
3.1.3
Budget and Personnel ............................................................................................. 36
4
References ............................................................................................................................. 37
5
Appendices ............................................................................................................................ 38
ii
List of Figures
Figure 1. SolidWorks model of the frame of the re-entry vehicle ............................................................... 3
Figure 2.Top View, Botton Portion of Ballute............................................................................................ 16
Figure 3. Dimensional View of Lower Ballute, Containing IMU .............................................................. 16
Figure 6. Re Entry Vehicle ........................................................................................................................... 4
Figure 7. Interior of Re Entry Vehicle .......................................................................................................... 5
Figure 8. Drag Coefficient of cones (Aerospace Web, 1997) ....................................................................... 6
Figure 9. Parachute Launching Mechanism .................................................................................................. 8
Figure 10. Schematics of the Balloon Train Assembly................................................................................. 9
Figure 11. Solidworks Models of Conceptual ZTR Device ........................................................................ 10
Figure 12. "Wright Device" ........................................................................................................................ 12
Figure 13. ZTR Alternate Design (Toggle Bolt)......................................................................................... 15
Figure 12. Von Mises Stress Analysis ........................................................................................................ 17
Figure 13. Deflection of Ballute ................................................................................................................. 18
Figure 14. ANSYS model of balsa ring ...................................................................................................... 19
Figure 15. Ground Speed vs. Time (min) of Packages due to atmospheric winds (2009-2010, 2011) ...... 22
Figure 16. Flight Path of Balloon (2009-2010, 2011)................................................................................. 22
Figure 17. Flight Path of Balloon (2009-2010, 2011)................................................................................. 23
Figure 18. Fight Path of Balloon (2009-2010, 2011) .................................................................................. 23
Figure 19 Accelerometer data from past groups (2009-2010, 2011) (Members, 2011) ............................. 24
Figure 20. Anticipated Results from Accelerometer in Red ....................................................................... 24
Figure 21: Launch 018 Flight Path ............................................................................................................. 26
Figure 22: Predicted Flight path from winds the night before .................................................................... 26
Figure 23. Altitude Profile .......................................................................................................................... 28
Figure 24. Ground Speed ............................................................................................................................ 29
Figure 25. Control Box on Landing ............................................................................................................ 30
Figure 26. Launch 020 Balloon Train Configuration.................................................................................. 31
Figure 27. Command Package Rigging ...................................................................................................... 32
Figure 28. Ballute Rigging .......................................................................................................................... 32
Figure 29. Predicted Flight path for launch 20 ........................................................................................... 33
Figure 30. Flight path for Launch 20 .......................................................................................................... 33
Figure 31: Launch 20 altitude profile ......................................................................................................... 35
Figure 32. Launch 20 Ground Speed .......................................................................................................... 35
iii
List of Tables
Table 1. Material Comparison....................................................................................................................... 3
Table 2. Comparison of ZTR Materials………………………………………………………………………………………………….11
Table 3:Budget……………..……………………………………………………………………………………………………………… 36
iv
1
INTRODUCTION
High altitude airborne developments such as airplanes and unmanned aerial vehicles have
presented huge advantages in the US military’s arsenal over decades through environmental
monitoring, precision navigation, communication, missile warning, and intelligence surveillance
and reconnaissance (ISR) platforms. However, considering that conventional aircraft have a
practical upper altitude limit (60000-80000 ft above the sea level), where engine efficiency
greatly diminishes due to lower oxygen levels, causing internal combustion, turbine engine
failure, certain restrictions apply. Thus, there exists a region of the earth’s atmosphere (about
60000 ft above the sea level) that remains underutilized. High-altitude maneuvering lighter-thanair platforms such as High Altitude Balloons uses the principle of buoyancy to take advantage of
this region and became potential platforms for ISR, precision navigation, environmental
monitoring, communication relays, missile warning, and weapon delivery. These vehicles can
provide persistent coverage over large areas of the earth’s surface with a substantially lower cost
than an earth-orbiting satellite, while providing longer loiter times and larger ground footprints
than conventional aircraft.
In 2005, the Wright State University High Altitude Balloon Team located in Dayton, Ohio
began its first development of high altitude mechanisms while being funded by the Ohio Space
Grant Consortium. Members of the team included current students, recent graduates, and
professors at Wright State University. The team since then has had over 17 successful launches
and recoveries from over 100,000 feet while being funded by the National Science Foundation.
During these launches, experiments have been conducted containing: temperature sensors,
cameras, video transmitters/recorders, and actuation devices. While experimenting, various
designs have been tested for the launching of a mechanism to withstand the high altitude and
environmental impact. Present designs include a two-box mechanism and a tear drop shape as
well. However, per future technology and advancement, the current High Altitude Balloon Team
is examining the possible success of a ballute aerodynamic decelerator design.
―Ballute aerodynamic decelerators have been studied since early in space age (1960’s), being
proposed for aerocapture in the early 1980’s‖ (Braun). The Goodyear Aerospace Corporation
coined the term ―ballute‖ (a contraction of ―balloon‖ and ―parachute‖ which the original ballute
closely resembles) for their cone balloon decelerator in 1962. ―The concept of the thin-film
ballute for aerocapture shows the potential for large mass savings over propulsive orbit insertion
or rigid aeroshell aerocapture‖ (Braun). Due to anticipated success of the ballute design as a
decelerator, the High Altitude Balloon Team anticipates to use the ballute structure as a
mechanism for the design of a balloon re-entry vehicle by using iron-on plastic as the thin-film
surrounding, balsa wood as the membrane, and an expanding balloon as the ballute ring. The
study of the ballute will include various manipulations to the structure of the balloon and
research of structural set-up of the high altitude balloon. These studies will be performed in the
1
High Altitude Balloon research lab located at 014 Russ Engineering Center, Wright State
University. Vacuum chambers, impact testers, and Computational Fluid Dynamics will be used
to enable the High Altitude balloon team to simulate high altitude occurrences in order to
successfully collect data from more than 60,000 feet above sea level.
2
DESIGN OF EXPERIMENTAL PROCEDURE
The high altitude balloon project has many design and performance specifications due to the
fact that the balloon travels through commercial air space. The most stringent specifications are
those imposed by the Federal Aviation Administration, FAA. Regulations for none pre
determined launches, meaning the team can launch the balloon without having to get FAA
approval, are that the weight of the load cannot exceed two six pound packages (Electronic
Code. Design specifications also include that all electrical components must be able to function
in a near space environment. A near space environment is the ―area between airspace and outer
space—65,000 to 325,000 feet above sea level‖ (Near Space Systems). This means that the
pressure that the vehicle will experience will be approximately one percent of what it is here in
Dayton Ohio, and that the vehicle and all it components must be able to function properly with
this constraint. The temperatures that the components experience are also a great constrain as the
temperatures can be anywhere from -70 to 100 degrees Celsius depending if the vehicle is in the
sun or shade (U.S. Standard).
The most important performance specification is that the complete balloon system must
disengage from each other properly. The complete balloon system consists of the balloon, a
already deployed parachute, the control box and finally the actual reentry vehicle.
In order for a launch to be considered a success several things must happen. The balloon
must detach from the control box parachute and the re-entry vehicle must detach from the control
box. This was done using a command cut down and timer switch. The re-entry vehicle at this
point starts its free fall for 35,000 ft and at 65,000 ft deploys its parachute. For the experiment to
be considered completely successful accelerometer data must be gathered for the duration of the
flight.
It is through the launch that this project gathered data and determined if the ballute design
chosen showed benefits in increasing drag stability. Various testing methods were used to ensure
that all devices functioned properly during the vehicles flight. These methods included, but were
not limited to, testing materials and components in a vacuum to simulate high altitude pressures,
cold testing to ensure functionality at high altitude like temperatures and general device testing to
guarantee specific tasks can be completed successfully. The last step in the experimental
procedure was actual launches of the vehicle. Once the vehicle was retrieved, the data was taken
from the collection package and analyzed. Please note: the flight can still be considered
successful if the vehicle is destroyed as long as the electrical components are not destroyed. The
2
vehicle’s main purpose was to gather data during its flight and safe guard this data so that it was
retrievable after landing. Essentially, as long as the structure protects the internal components,
the launch is a success. The vehicle was made from easily replaceable and inexpensive
components so that a complete rebuild could be quickly and easily achieved.
2.1
Fabrication
The ballute was mainly fabricated from balsa wood. Balsa wood was chosen as a material
due to its high strength to weight ratio. As can be seen in table 1 balsa wood has the highest
strength to density ratio of the materials looked at, therefore was chosen for the material to use to
build the frame of the vehicle.
Table 1. Material Comparison (Matbase)
Material
Balsa wood
Birch wood
PUR (flexible foam)
PUR (hard foam)
Density (kg/m3)
130
610
100
20
Strength (MPa)
75
270
1.1
0
Ratio
0.5769
0.4426
.011
0
A small laser cuter which can cut sheets of up to 12 by 24 inches was used to cut the balsa
wood. This device works by using a CAD drawing which has been formatted to a 1:1 scale and
then cutting out the exact lines that are shown in the drawing. The body of the vehicle is made up
of concentric circles and struts as is shown in Figure 1.
Figure 1. SolidWorks model of the frame of the re-entry vehicle
3
All of the circular sections were cut using the laser cutter and struts were bought and
conformed to the geometry desired for the structure by hand. The pieces were then glued
together using R.C. Hobby extra thick glue. This structure was then covered in an iron-on plastic,
which shrinks to form to the contours of the body. A foam tip was attached to the body to help
absorb some of the impact when the vehicle touches down. Insulation was also inserted into the
bottom of the ballute to protect the electronic components used during launch. As previously
stated, decreasing temperatures cause strenuous effects to the strength of different materials at
high altitudes. Thus, blanket insulation made out of polyester and cotton was rolled and aligned
along the edge of the ballute. To assist in protecting the electronics from cold temperatures,
hand warmers were added pre-flight. Figure 2 and 3 display the full ballute structure.
Figure 2. Re Entry Vehicle
4
Figure 3. Interior of Re Entry Vehicle
The body is made of two sections to allow the electronic components to be mounted and
moved with ease. All of the electronic components are housed in the bottom section and the
parachute is housed in the top section of the ballute. The final dimensions of the cone are a base
of a diameter of 2’ and a height of 20.78‖. The angle of the cone is 30 degrees from center. The
optimum angle was determined based upon drag, volume and strength. As can be seen in Figure
4, as the angle of the cone increases so does the drag coefficient, with the largest drag for
essentially a plane. The optimum angle to chose would be 90 degrees because it gives a large
drag coefficient, but this wide of cone could have stability issues due to it being essentially a flat
plane. Considering these facts, and the fact that the ballute will add drag which is lost due to a
lower angle, 30 degrees was chosen. This angle also gives an adequate amount of room for all
the electrical components, antennas and parachute deployment device that must be placed inside
the structure. Larger angles also decrease the strength of the structure so the 30 degree angle is
the optimum angle for this application. The design of the cone was based upon the structure of a
balsa model airplane.
5
Figure 4. Drag Coefficient of cones (Aerospace Web, 1997)
After the angle of the ballute vehicle was chosen a terminal velocity could be estimated using
Equation 1. The drag coefficient,
, was assumed to be 0.5 when in actuality it should be
greater due to the addition of the ballute to the cone. The weight was assumed to be at maximum,
6lb. This equation was solved at several altitudes and it was estimated that the vehicle would be
descending at a peak rate of 60 mph but should only be descending at approximately 21 mph
upon impact to the ground. These estimates are assuming no or partial parachute deployment, so
one can imagine how much slower the vehicle would be traveling considering a successful
parachute deployment.
Equation 1
2.1.1
Ballute
The actual ballute section of the vehicle was attached to the base of the cone. Several
different materials were considered for the ballute ranging from aluminum hose to pool floaties.
The issue with an inflatable ballute was the differences in the air pressure at various altitudes and
the unpredictability of the exact behavior of the material in these conditions. A vacuum was used
to study the effects low pressure on various inflatables. Due to the pressure at 100,000 ft being
1.01kPa the volume of a gas, such as air, that a sealed vessel will contain would grow to
approximately 74 times its original volume. This ratio was obtained by using the following
equation:
6
Equation 2
The P1, V1, T1 values were taken to be at the altitude of Dayton Ohio which is
approximately 224 ft above sea level. The P2, V2, T2 values were taken to be at an altitude of
100,000 ft. From this equation, leaving the volume at 100,000 ft the only unknown, the ratio of
1:74 was obtained. This equation is considering air as an ideal gas, which it will not be, therefore
this ratio was only an estimate and considered with limited dependency when testing various
materials.
Another material that was tested was aluminum and vinyl dyer vent hose, as it is rigid and
can be formed to the desired shape. The aluminum hose was not used due to its interference with
the antenna signal that needed to be clearly sent out of the ballute and associated weight. Thus, a
vinyl dryer vent hose was used due to the light weight of the material and flexibility (as
mentioned before) to be formed into various shapes depending of the design. The end goal of
using the ballute was to increase the drag of the vehicle which was tested during the free fall of
the launch.
2.1.2
Parachute
Previous measurements have been made to describe the ballute’s return into the
atmosphere. These measurements include a drag of 125 mph and impact velocity of 45 mph.
Thus, a successful parachute was needed to ensure a safe return. For the current ballute design, a
cylindrical device was built of plastic with a spring launching device in order to apply a force to
assist with deployment. Household items such as popcorn containers, flour containers, or 2-liter
cola bottles were tested to find a reasonable diameter and depth. However, due to weight
limitations, choices of cylindrical material were limited thus; experiments were needed to choose
the most optimal material. These experiments included releasing a sample from a large height
and measuring the impact results. Following experimentation, a popcorn cylinder was chosen for
the parachute deployment container due to its strength during test, light weight properties, and
larger diameter to ensure a clean release of the parachute without causing a lot of friction. A
fiberglass arrow was used along with an eye bolt to allow for release and a thin but, strong disk
made out of balsa wood was glued to the end of the fiberglass arrow to impulse the parachute
which will be in the middle of a compression spring. A string which was burnt by nichrome wire
connected to a timer switch was attach to bottom of the arrow and pulled back to allow for the
7
user to activate the deployment. The Figure 5 displays a simple mechanism used for parachute
deployment.
Figure 5. Parachute Launching Mechanism
The following equation (Equation 2) was used when determining the proper spring for
the parachute deployment. The force to apply depends on the amount of drag and weight
experienced by the parachute when compact to overpower these amounts when deploying. Thus,
a 20 gauge shot gun spring was used to overcome these forces due to the availability, spring
properties, and length. To ensure a successful deployment, a disk was used (as stated before) and
mounted at the end to overcome the amount of force experienced by the parachute in flight.
8
Equation 3
2.1.3
Release Mechanism
As the balloon rises to altitudes of approximately 100,000 feet, the balloon expands with the
greatly reduced pressure and eventually ruptures. The balloon does not break and come off the
assembly clean, but bursts into hundreds of stringy remains that wrap and twist around the other
components. Schematics of previously implemented balloon trains are shown in Figure 6, where
the left figure represents the assembly from launch to 100,000 ft and the right figure represents
the balloon burst. Note the release mechanism (here, the ZTR) location above the payload and
parachute.
Figure 6. Schematics of the Balloon Train Assembly
Since the exploded balloon remnants stay intact on the entire descent, many tangle issues
can arise as the parachute attempt to deploy. This could potentially result in a complete free fall
from 100,000 ft, which is detrimental to the vehicle and hardware within, causing potential
failure of data analysis.
In past years, not a single group has incorporated a device that cut the balloon from the rest
of the package/parachute assembly. Although the previous design teams have successfully
launched 17 projects, there has not been a single successful parachute deployment. This could
partially be due to the tangled balloon mass wrapping around parachute lines and causing major
malfunctions. The goal this year was to create a mechanism, using previous research and
9
designs, and successfully incorporate this replication in the 2011 HAB Team’s projects and
possibly future use. Two devices were pursued; one of which was a zero tension release, the
other was a harness for a direct line cut.
The zero tension release method relies on the physics behind the balloon rupture to release
the payload. Previous teams have tried, without success, to use a similar design to release the
balloon. As the balloon bursts, the device (mounted in-line with payload as shown in Figure 6)
experiences no tension. This allows the device to open, releasing from the balloon. In order to
model both designs, the components were created in the CAD program Autodesk Inventor.
The previous ZTR device, partially shown in Figure 7, works with simple calculations using
the weight of the payload, the tension created by the balloon, and the force of an extension
spring. The orange ring is tied onto the end of a string that attaches to the balloon. The blue
arrow pointing up indicates the direction of the balloon’s tension force. The holes circled in red
are the holes that strings tie through in order to connect to the rest of the payload. The red
arrows signify the direction of half the weight force of the payload. The black arrows show the
direction of the spring force. After inflation, the balloon rises at a constant rate, and looks much
like the configuration shown in Figure 7. The ZTR does not fire because the moment caused by
the weight force at each point exceeds the moments created by the spring, keeping the device
closed. When the balloon finally bursts and the entire assembly is in free fall, the balloon
tension force will no longer be present. Since the ZTR and payload falls at a relatively similar
speed, the weight force is almost non-existent. This phenomenon now allows the moment
created by the spring to govern, which causes the spring force to open the device as seen in
Figure 7.
Figure 7. Solidworks Models of Conceptual ZTR Device
10
The ZTR device is designed to release the balloon on bursting, but is equipped with both a
safety and secondary release. The safety consists of a string tied across the top of the ZTR (Top
holes located on the two plates seen in Figure 7) attached to a Nichrome wire burn unit. As the
balloon rises in altitude, it passes some very turbulent air within the first 4,000 ft of its journey.
The balloon train experiences immense vibrations and this disturbance could trigger the ZTR to
feel zero tension from the balloon and fire early. To prevent this, the string locks the device
together until the balloon passes through the turbulent atmosphere. At this point the Nichrome
wire burn is remotely fired, and the string cuts arming the device for a normal zero tension
release around the 100,000 ft mark. The secondary release incorporates another Nichrome wire
burn that can also be manually controlled. Although the HAB team has wind predicting leaders,
sometimes the weather patterns shift swiftly. If the team ever finds that the launched package is
heading directly over regulated airways, (WPAFB, airports, etc.) the mission can be abandoned
with a remote signal activating the Nichrome string burn directly under the ZTR device. This
controlled release can also serve as a backup or secondary cut in case the mechanism does not
fire properly. In this scenario, the controlled burn release would occur sometime after the ZTR
device malfunctioned. In an attempt to salvage the mission, the secondary release would be
activated and the rest of the package would theoretically separate from the balloon remains.
The ―Wright Device‖ is a mechanism that effectively detached the balloon from the
command box and ballute assembly upon command. The ―Wright Device‖ successfully enabled
true free fall testing (no trailing balloon fragments) and prohibited parachute tangling.
The ―Wright Device‖ mechanism inspired by the ―Iowa Device‖ from Iowa University
contains multiple components enabling the ballute and control box to release properly from the
balloon at 100,000ft. One major improvement on the previous ―Iowa Device‖ is the
implementation of the device inside of the control box, rather than externally. There are multiple
benefits to this design; namely the improved reliability that comes from limited exposure to the
elements. It has been found in prior experience that nichrome becomes brittle and tends to break
when exposed to cold and loading. The ―Wright Device‖ successfully limited the cold exposure
and eliminated any loads carried by the nichrome wire. The ―Wright Device‖ setup used for
Flight 18 is shown in Figure 8.
11
Figure 8. "Wright Device"
The main body of the device is made out of a household plastic electrical box, which proves
to be very cost efficient and uses nylon string to the hold the package’s load for extended periods
of time. The nylon string was cut by two 28 gauge nichrome wires which were triggered by a
signal to the DTMF board inside the control box. By using two different burns, each on a
separate channel, the redundancy of the ―Wright Device‖ ensures a more successful release from
the balloon. The voltage supplied to each wire was 6 V, supplied by two completely independent
batteries for reliability. Once the nylon string was cut from the nichrome wire, the ballute and
control box released as a result of running the string through both packages to the balloon.
During launch, all nylon string is in tension causing a clean cut from the nichrome boards.
When looking at the pros and cons of a Zero Tension Release vs. the ―Wright Device‖, it
became clear that the ―Wright Device‖ would be more likely to provide a successful release from
the balloon. One problem with ZTR is the necessity for safety burns, only further complicating
the device. Also, research has shown that wind is not always calm at altitudes above 30,000 ft as
previously thought, which would instigate an early release of the payload, jeopardizing the
mission. Also, the ZTR requires external nichrome burns that have been shown ineffective in
past launches. The ―Wright Device‖ eliminates all external wiring and burning operations. In
addition to this increase in reliability, it offers a method to release the payload before the balloon
has bursted, which eliminates any possibility of tangling. As previously mentioned, the ―Wright
Device‖ also implements two separate nichrome burns, on separate channels for redundancy.
For the re-design of the current device, there are a few key areas that are targeted for
improvement. One of these areas is friction due to bolts on the spring bracket contacting each
other. The solution for this is to move the mounting location of the bracket from the side of the
12
ZTR plate to the bottom of the plate, because the bottoms of the plate never come in contact with
one another. Another key area is the notch that houses the ring attached to the balloon. After
some testing was done on the device from last year, it was found that the ring can exert all its
upward force on one plate, rather than evenly distributing the load on both. This phenomena
causes the device to tilt due to uneven loading, thus the ring is never released. Current re-design
strategies will take this into account, and avoid this problem. The third problem is reducing
friction in the axle about which the device rotates. In order to counter this, new material will be
chosen to have less friction, while maintaining stability of the plates. A bearing mechanism will
be utilized to stop this problem. However, much care must be taken when choosing materials to
make sure the extreme cold will not cause brittle failure in the device. Also, a low coefficient of
friction is preferable to avoid potential jamming of the device. Table 2 shows the properties that
were taken into account when choosing materials for fabrication.
MATERIAL
COEFFICIENT OF
FRICTION
TEMPERATURE
RANGE (⁰F)
NYLON 6/6
HDPE
LDPE
UHMW
PVC
PEEK
.15-.25
0.28-.35
.2-.4
.10-.22
---0.25-.3
-22 TO +210
-40 TO +149
-40 TO +125
-452 TO +200
-99 TO +60
-99 TO +400
19.53
5.08
4.94
11.16
6.57
291.99
NYLON 6/6
UHMW
PTFE
Glass-Filled
PTFE
VESPEL
.15-.25
.16-.18
0.1-.15
-20 TO +250
-200 TO +180
-350 TO +500
0.43
7.31
3.09
.1-.15
.12-.18
-350 TO +500
-400 TO +550
3.34
58.52
TEFLON PTFE
VESPEL
RULON
KEVLAR/HYDLAR
Z
UHMW
.12 TO .15
.12 TO .18
.1 TO .13
-350 TO +500
-423 TO +550
-400 TO +550
1.44/FOOT
26.48/IN
19.82/FOOT
.23-.25
.17-2.1
-40 TO +300
-40 TO +185
6.35/FOOT
1.86/FOOT
COST
PLATE
BEARING
ROD
Table 2. Comparison of ZTR Materials
13
As can be seen in table 2, the selected material for the ZTR plate was UHMW (ultra-high
molecular weight) plastic. This material demonstrates a low coefficient of friction, a great
temperature range, and a relatively low cost. The material chosen for the bearings is PTFE
(polytetrafluoroethylene). This material exhibits an extremely low coefficient of friction, and
satisfactory temperature qualities. Although Vespel may be a more prime candidate based on
friction and temperature, the cost of Vespel is extremely high, thus it is not practical for the
application (most likely one time use scenario). As for the central rod, the decision is a Virgin
Electrical Grade Teflon PTFE. Because the rod serves as the axis about which everything rotates,
a low coefficient of friction is especially important here. Choosing Teflon PTFE over Rulon was
a difficult decision, because they are very equally weighted in benefits. While Rulon exhibits
better physical properties, it has a much higher cost. Due to the one time use nature of this piece,
it is more optimal to choose a material that will cost less when a rebuild needs done.
An alternate ZTR design involves a wall anchor toggle bolt to release upon zero tension in a
similar way to the ZTR device described above. The toggle bolt ZTR utilizes the forces
surrounding a torsional spring and an angled housing box. The toggle bolt’s clips are positioned
in the housing so when tension from the balloon is exerted, the clips open wide. This prevents
the bolt assembly from slipping through the housing. When the balloon finally ruptures the same
weightless phenomena occurs (as described above) and the torsional spring forces the clips to
shut. This enables the bolt to pass through the housing, hence separating the balloon from the
payload. The simplicity of the design reduces the chance for mechanical failures at remote
distances, which makes it much more favorable over the original ZTR. Since this device was
never previously explored, much more testing must be performed before realistically considering
employment in the HAB project.
14
Tension from Balloon
Payload Weight
Payload Weight
Figure 9. ZTR Alternate Design (Toggle Bolt)
2.2
Measurement and Testing
In-depth dimensions for each part of the ballute were obtained using the SoldWorks model
of the ballute. During freefall, the geometry of the ballute is key in stability properties. If freefall
accelerometer data were gather, the placement of the Inertial Measurement Unit (IMU) is critical
in determining characteristics such as ballute orientation and moments of inertia. Figures 10 and
11 show dimensional details.
15
Figure 10.Top View, Botton Portion of Ballute
Figure 11. Dimensional View of Lower Ballute, Containing IMU
Cold testing was done on the electrical components to ensure proper insulation was used for
the device to function properly at altitude. This cold testing was conducted by using dry ice to
bring a chamber down to approximately -20 degrees Celsius and measuring the voltage output
and functionality. These results allowed us to modify and insulate in the most efficient matter,
minimizing the weight allocation needed for insulation.
16
Due to the critically important parts inside the ballute frame, it was imperative that the
structure withstand the shock and vibration that is associated with descent and landing. If the
IMU or data logger were destroyed, there would be no freefall data to gather, resulting in
experimental failure. In order to simulate the forces experienced during landing, the Von Mises
stresses and deflections of the ballute were modeled in SolidWorks. The first scenario modeled
was the stress on frame alone during impact. This showed that the supporting rods successfully
distribute forces along the ballute rings.
Figure 12. Von Mises Stress Analysis
Also modeled in SolidWorks was a deflection case. For this case, a loading scenario was
modeled as follows: The bottom would remain fixed, while the load is applied on the upper
rings, which accurately simulates the electronics and mounting thereof. For a worst case, twice
17
the weight of the ballute was applied, or 7.5 lbf. This accounts for some of the dynamic loading.
See Figure 13.
Figure 13. Deflection of Ballute
The parachute deployment system had many initial tests to ensure functionality. Due to the
unpredictability of tumbling and wind gusts the true testing will come during the launch.
Accelerometers housed in the vehicle and cameras allowed for review of deployment in the field.
From the data gathered it was seen when the parachute deploys, if it was at the desired time, and
18
how well it deployed. The wellness of deployment was the parachutes ability to catch the air and
begin to slow down the decent of the vehicle.
ANSYS was used to see the effects the parachute deployment shock will have one the Balsa
structure. Data from these analyses benefitted with design group to refine the design of the whole
system, allowing for a successful launch and optimization. The ANSYS ring model is shown in
Figure 14. This analysis showed a deformation of only 0.138x10-5m for a worst case force which
would exceed the actual force experienced.
Figure 14. ANSYS model of balsa ring
Once the balloon reached maximum altitude and/or bursts, the re-entry vehicle and control
center separated. At altitudes in excess of 60,000 ft, the free fall trajectories of these two devices
vary dramatically. In order to track the control center and re-entry vehicle separately, multiple
devices were stored on separate parts of the system. In this manner, each device was tracked to
its own separate landing location.
In order to track the re-entry vehicle, devices were installed inside. The primary mode of
tracking the device is an APRS transmitter. This is used in conjunction with a Kenwood D710
AV Map apparatus. The transmitter inside the ballute, a Byonics MicroTrak 300, broadcasting a
call sign of W1 WSU-11, is tracked with the Kenwood via repeater stations. The MicroTrak
broadcasts data including position and altitude back to the Kenwood. The transmitter inside the
control box, an Argent OT+1 tracker broadcasting via Puxing handheld, broadcasted on a
separate call sign (W1 WSU-12). This device is also programmed to relay latitude and longitude
coordinates, along with altitude readings. The display on the AV Map would show the current
location of the systems, and also gives a direction and distance to the units. With this system, the
team was directed during both launches to a close proximity of the landing location.
Once within a close range of the landing site, the CW beacon was used to successfully locate
both the command box and the ballute. This beacon is independently powered by a nine volt
battery, and broadcasts a morse code signal every minute via a dipole antenna. In order to track
19
this device, a directional antenna is implemented to detect null zones, thus is can be determined
the general direction of the signal. Although the AV Map gives a close proximity of the
whereabouts of the re-entry vehicle, there was a good chance it may not have been visible at first
glance (i.e. it could land in dense shrubbery, water, a ditch, etc.). Once the area of search was
narrowed down, the ―fox hunting‖ beacon (utilizing radio direction finding techniques) showed
operators a more specific location.
Implementing all of these new devices in only one flight involves many risks. Although
many of the mechanical systems and electronic circuits were cold/vacuum tested, all of these
were executed at ground level. For this reason a test launch consisting of just the control box was
organized and carried out on April 30th, 2011. This test would eliminate some of the variables
associated with testing the control box and ballute together, while still allowing several
experiments on new devices to occur. The test launch was intended to go to 50,000 feet to test
the new mechanisms, materials, and configurations this years’ team had developed. A timer
switch which was ultimately being mounted in the ballute, and tracking systems were also tested.
This launch allowed the team to fully understand all the necessary steps that must be taken for a
successful launch and experimentally analyze changes for future launches. Details and results of
this test launch along with other launches are discussed in section 3.1.1 of this report.
3
RESULTS
During the testing of the ballute experiment and control box, the following procedures were
done on the day of the launch. Weather predictions were made that day which predicted the wind
direction and speed. Depending on the wind speed and direction, the location of the launch will
have to be selected on that day. This is important for the recovery of our ballute because the team
will want the packages to land in a place where it will be easy to retrieve along with the safety of
the experiment and public in mind.
After the lunch location has been chosen, the balloon will be filled with the appropriate
amount of helium and released so that testing may begin. The amount of helium depends on the
balloon size and the temperature where the helium is being inserted into the balloon. To calculate
the amount of helium needed for the flight, an existing MatLab program written from past groups
must be utilized. This program calculates the final volume of the balloon after it is filled to the
correct amount. Using the relation
the amount of helium extracted from the tanks is
found. Where is the volume of the tank,
is the pressure in psi at the altitude of Dayton and
is the volume of the balloon calculated by the MatLab program in
. The volume the
MatLab program calculates is dependent on the temperature at the location the balloon is being
filled, balloon size and weight of the system. When filling the balloon, a pressure gauge on the
20
tank allows the user to see the pressure from the tank that has gone into the balloon which is the
value that was calculated.
Plastic gloves will be required while handling the balloon. The reason for this is because oil
from the operator’s skin could become a problem when the balloon climes to elevations with
extremely low temperatures. The low temperatures will freeze the oil and this will hinder the
balloon from expanding properly where the oil is located on the surface of the balloon, thus the
balloon may rupture. This has been a problem in the past so the team must be very scrupulous
when handling our balloon.
Following the launch, the group will start heading for the predicted landing spot of the
balloon which was predicted by the flight prediction. The team will be able to track the two
packages by using the APRS, and fox hunting beacon inside the two packages and
communicating with the HAM radios.
Subsequent to the balloon reaching approximately 100,000 feet or the balloon bursting, a
signal will be transmitted to the control box (which is attached to the balloon and ballute) to
release from the balloon and ballute by burning the nicrome wire. When the ballute separates
from the control box, a pin attached to the control box and will pull out from the ballute starting
a timer. The ballute will free fall for ten minutes or approximately 35,000 feet until it reaches
65,000 feet. The control box will not free fall but will descend to the ground with a parachute
attached to it at all times.
After the ballute has free-fell for 10 minutes, a timer will signal the nicrome wire burn for
release of the parachute mechanism. The mechanism will be a compressed spring that is being
held by a string in tension, thus when the nicrome is burnt, the string will no longer be in tension
and will release the spring ejecting the parachute. The parachute will deploy and allow the
ballute to descend to the ground safely and unharmed. The team will be following the ballute and
control box around, waiting for them to land for recovery. Following recovery, the team will be
able to retrieve the data inside the ballute from the accelerometer to determine if the ballute
slowed the decent of the package during the free fall. It is expected that the ballute will slow
down the decent.
Wind predications are paramount during the day of the experiment. The reason is that if the
wind is to strong in the upper atmosphere, the flight may be delayed. If the wind is to strong, the
team may have to go to great lengths to retrieve the packages. The team does not want to go
cross country to find the experimental design. Also, the wind predictions will allow the team to
get a head start with regards to retrieval. With wind predictions, the team can anticipate the
general area where the experimental packages it will land.
21
Figure 15. Ground Speed vs. Time (min) of Packages due to atmospheric winds (2009-2010,
2011)
In figure 15 it can be seen that the upper atmospheric winds can carry the packages for
many miles before they come to the ground. In this graph, the winds carried the packages in the
past beyond 160 Mile per Hour at the peak.
Figure 16. Flight Path of Balloon (2009-2010, 2011)
22
Figure 17. Flight Path of Balloon (2009-2010, 2011)
Figure 18. Fight Path of Balloon (2009-2010, 2011)
Figures 16, 17 and 18 show the flight paths of three different launches. This goes to show that
the wind predictions for the day of each launch are different and very important for the teams to
retrieve the packages.
Also, it is unknown how the ballute will descend. This is where an onboard camera along
with an accelerometer with three axes will evaluate the free-fall of our ballute. The major result
from this experiment is how the ballute contributed to the decent of our design. This data will be
gathered by the accelerometer inside the ballute design.
23
Figure 19 Accelerometer data from past groups (2009-2010, 2011) (Members, 2011)
Figure 19 shows the type of data that the accelerometer will gather from the decent of the design.
This data was from the past group for year 2009-2010 which did not use the ballute concept.
Figure 20. Anticipated Results from Accelerometer in Red
The hopes of the ballute are that decent will dramatically decrease from the point it is
released from the control box. Figure 20 in red shows how the accelerometer data will change
24
with the ballute concept. The decent may take longer than in the past because the drag from the
ballute will slow the decent, this is the aspiration of the ballute.
Also, the success of the parachute deployment and Wright Device is another major project
parameter the team wishes to achieve. The team will plan and design our project around what
could possibly go wrong and hope for the best.
3.1.1
Launch 18 – April 30th 2011
The first launch served as a primary test flight for the control box. During this launch the
control box configuration and command cut down were tested. Also tested was the timer switch
that would be used to start the timed nichrome burns in the ballute used for parachute
deployment. The only thing that changed from the configuration launched and that used with the
final launch was the addition of two nichrome burns and the removal of the switch. The control
box also had a head camera mounted inside with its field of view being the side. This allowed for
better understanding of the path the balloon took and how the control box and parachute
interacted with the balloon.
The launch site chosen was Wright State University Lake Campus due to the flight prediction
showing an ESE direction. A 2000-gram old stock balloon was chosen due to a
miscommunication in new balloon orders. The Balloon was launched at 887ft and reached a
maximum altitude of 55,980 ft. At this altitude a command cut down was initiated (first ever by a
Wright State University team) several minutes after the cut down signal was sent another
transmission came in showing that the package began to lose altitude. This indicated that the cut
down from the balloon was successful. From later video evidence, the burn and complete release
took approximately 13.5 seconds. Figure 21 shows the complete flight path of the balloon. The
reason for this low altitude cut down was because of the lack of trust placed in the balloon. The
balloon used was a year old and had been exposed to light due to this the balloon was unreliable
for a high altitude flight. The purpose of this flight was to cut the control box from the balloon
while it was still inflated and the burst altitude of this balloon being unknown because of its
condition.
25
Figure 21: Launch 018 Flight Path
Figure 22: Predicted Flight path from winds the night before
Figure 22 shows the predicted flight path from a sounding the night before the launch. As
one can see the two paths were fairly close taking into account that there was at least a 12 hour
lag from the data to the actual launch time. There was an issue with the APRS in that it did not
transmit altitude data along with its position every time. It is believed that this was due to
antenna and GPS placement. Both were placed on the side of the control box. Since the control
box spun during the entire flight so did the antenna, making it difficult for the GPS to get a clear
grasp on its location. After this flight, the conclusion for the next flight was that the antenna must
be pointing toward earth and the GPS must be placed on top of the box.
26
The main objective of the test flight was to validate the reliability of a command cut-down.
This cut-down involves a multitude of mechanical and electrical systems that have never been
tested. One of the objectives was to test how efficiently a Puxing handheld radio could receive a
signal sent from the ground and rely this signal to the DTMF (dual tone mulit frequency) board.
This board contains eight outputs that can operate a variety of different electronics. The
command box’s DTMF board utilized three of these channels. Both channels one and two were
used for nichrome burning lead wires that were encased by the ―Wright Device.‖ As stated
previously, at the altitude of approximately 55,000 feet, the DTMF signal (*1) was sent from a
moving vehicle’s Kenwood D710 radio. The second signal (*2) was shortly sent afterwards to
ensure a complete and successful command box release from the balloon. The third channel was
used to initiate the siren of an electronic screamer that would help locate the box during recovery
on the ground. This signal was sent while the command box was at an altitude of approximately
8,000 ft. Although the first burn signal was never received, the second one was, effectively
separating the command box from the balloon. The screamer signal was also received at the
appropriate altitude, and both of these can be confirmed through the audio on the flight video
recording.
The launch also tested the new parachute attachment configuration that is associated with the
―Wright Device.‖ A strap with a small ring was sewn on the top of the parachute. The string
attaching the balloon to the control box was fed through this ring which helped hold up the
parachute in a deployed position and also allowed the string to be pulled through when cut below
by a nichrome burn. This small device allowed the connecting string to pass through for a tangle
free balloon release.
The pull pin release was tested, but not for its original purpose. Prior to flight, the pin’s
string was removed to avoid possible entanglement with the parachute. The original plan was to
connect this string to the balloon’s string, so when the ―Wright Device‖ released the balloon
from the command box the pin would be pulled out. The pin removal would simulate the pull
pin timer-switch that was later installed in the ballute. Although the string was removed, the
flight proved that wind vibrations would not be enough to remove the pin on its own.
Another test executed in the test launch was the video recording capabilities at high altitude.
Although the Tachyon camera is water proof and very durable looking, no other balloon group
had created live video of the entire flight path of the balloon. The video recorded from our test
flight proved that this was possible, while also providing evidence for other tests via the audio
data.
Other tests that were not unique, but never performed by our group, were also accomplished
during the launch. This included the APRS and beacon tracking abilities of the group during a
live flight, although the beacon directional finding was never needed because the APRS gave the
exact coordinates of the command box upon landing. The balloon filling and flight preparation
was also practiced during the flight. Good preparation provided relatively quick pre-flight repairs
27
and balloon fill calculations/procedures allowed for an excellent balloon ascent rate. The Stable
climb rate can be seen in Figure 23. The Ascent was very linear and if calculated comes out to
approximately 1400 ft/min.
Launch 018: Control Box Altitude
Profile
60000
Altitude (ft)
50000
40000
30000
Series1
20000
10000
0
0
10
20
30
40
50
Time (Min)
Figure 23. Altitude Profile
Figure 23 shows the ground speed according to the GPS tracking. These values were not taken as
vectors, meaning that there is no negative sign to distinguish from ascent to descent. This was
due to the data being from the GPS tracking and the only way to tell if the package was going up
or down was the time stamp.
28
Launch 018: Ground Speed
120
Ground Speed (MPH)
100
80
60
Ascent
Descent
40
20
0
0
10
20
30
40
50
60
Time (min)
Figure 24. Ground Speed
Figure 25 shows the control box position after landing. The only damage that can be seen is that
the CW beacon antenna wires were broken and bent. This is due to the wire casing becoming
brittle in the cold temperatures and fracturing in the turbulence.
29
Figure 25. Control Box on Landing
The test flight was considered a success on all accounts. The command cut down was
completed, the timing switch was not jostled loose, the box was recovered and video footage was
taken during the entire flight. Lessons learned from this launch were: to check and recheck all
connections prior to launch and antenna placement is key in the reporting transmissions of
location. The GPS antenna was moved to the top of the control box and the APRS antenna
moved from its horizontal orientation to a vertical one. The relocation of the antennas would
hopefully align the null zones to more optimum location to help ensure there is a clear signal
path.
3.1.2
Launch 20 - May 31th 2011
Currently, the High Altitude Balloon Team is completely finished with manufacturing and
experimentally testing the system. May 31rd, 2011 was chosen as the final date for the launch.
Delays were due to the upcoming event ―Ham Vention‖ in the area in which numerous HAM
radio users use various frequencies to communicate during a recreational locating event. This
event could potentially jeopardize the experiment as a result of the APRS tracking system being
dominated by local HAM radio users. Another delay were the numerous thunderstorms we have
30
been experiencing in the greater Dayton area. While waiting, the High Altitude Balloon team
continued simulating launches to modify experimental set-up in order to successfully launch in
the near future.
The following figures depict the CAD models of balloon train configuration for launch 020.
As can be seen, the same control box implementation as launch 018 was used. This enabled the
―Wright Device‖ to make a single cut that released both the command package from the balloon
and the ballute from the command package. With the ability to release both packages with one
single cut, many causes of failure were eliminated, i.e. tangling of lines, failure of electronics,
and failure due to vibration at free fall speeds.
Figure 26. Launch 020 Balloon Train Configuration
31
Figure 27. Command Package Rigging
Figure 28. Ballute Rigging
32
Figure 29 and Figure 30 show the predicted and actual flight paths respectively. The winds
were very calm on the launch day resulting in a very short distance flight. Due to this the team
was able to launch from nearby Wright State University and still avoid any restricted air space.
The launch site chosen was Sackett-Wright Park in Bellbrook Ohio.
Figure 29. Predicted Flight path for launch 20
Figure 30. Flight path for Launch 20
33
The flight was considered partially successful. Excellent video footage of the flight was
obtained from two angles, out over the horizon from the control box and up at the balloon from
the ballute. Everything went as planned except for the failure of the micro-trak in the ballute. The
ballute stopped transmitting data at approximately 80,372 ft and did not start transmitting again
until the package fell to 46,184 ft. Due to the loss of transmission at the apex, the decision was
made to keep the control box and ballute as one package. This meant leaving the balloon to burst
naturally and command box and ballute fall as one, which occurred at 95,000ft. This was under
the desired 100,000 ft but the slightly early release was likely due to increased humidity of the
chosen launch day. The descent was very violent due to the ballute still being attached to the
control box. The fact that it stood up to that abuse was a structural achievement. It was during the
violent turbulence caused by the balloon burst that the plastic tubes broke. Therefore if the
nichrome would have been burnt before the balloon burst as planned, the tubes would have done
their job. This theory of the tube failure is proven in the ballute video.
The violent landing shoved the plastic tubes into the top of the ballute causing some
structural damage upon impact. As seen in the video the pull pin string was not tangled when the
balloon burst meaning the pin would have pulled out to start the parachute deployment with ease.
When the ballute was brought back to the lab the parachute deployment was tested by simply
pulling out the pin. At this point the ballute configuration had not been touched, it was the same
as when found upon landing. The deployment worked successfully and the team is completely
confident that it would have worked just as well at altitude.
Overall the structure worked very well for how much it weighed. It experienced fracture
in two places, most likely on landing. These two places were not critical for withstanding the
parachute deployment or protecting electronics positioned inside. They were located on the top
ring on one side, leading to the theory of impact damage. The damage was so minor that it could
be fixed with glue or epoxy. The control box worked flawlessly and is ready to be launched
again.
The accelerometer successfully recorded data during both ascent and descent, and the
data was safely recovered, as can be seen in the appendices. The accelerometer data was not
conclusive to freefall theory due to the fact that the re-entry vehicle was not released from the
control package. The aerodynamics of the ballute were jeopardized upon failure to release, due to
the trailing control package and ruptured balloon. The plastic guide tubes may have been a factor
in the randomness of orientation during descent. This can be seen in the video.
34
Launch 20: Altitude Profile
100000
90000
80000
60000
50000
40000
Series1
30000
20000
10000
0
0
10
20
30
40
50
Time (min)
Figure 31: Launch 20 altitude profile
Launch 20: Ground Speed
50
45
40
Ground Speed (Mph)
Altitude ft
70000
35
30
25
Ascent
20
Descent
15
10
5
0
0
10
20
30
40
Time (min)
Figure 32. Launch 20 Ground Speed
35
50
3.1.3
Budget and Personnel
Product
Vendor
1/4" X 1/4" X36" Balsa Stick
1/4" X 6" X 36" Balsa Sheet
Neon Orange Monokote
2.0 oz Super Thin Glue
2.0 oz Extra Thick Glue
Epoxy
R.C. Hobby
R.C. Hobby
R.C. Hobby
R.C. Hobby
R.C. Hobby
R.C. Hobby
Knickerbocker
Pools and SPas
Knickerbocker
Pools and SPas
Knickerbocker
Pools and SPas
Menards
Menards
Menards
MENARDS
MENARDS
MENARDS
MENARDS
MENARDS
Menards
Menards
Menards
Home Depot
Home Depot
Home Depot
Home Depot
Spherachutes CO
Spherachutes CO
DICKS SPORTING
R.C. HOBBY
R.C. Hobby
Target
Home Depot
TARGET
TARGET
30 in. Pool Tube
36 in. Pool Tube
Screen Print pool Arm Bands
1 Pint Funnel
5"X8' Flex Aluminum Duct
1/4 X4 " Toggle Bolts
#4 x 1/2" WOOD SCREW
16" COPPER PLATED BRACKET
1/2" X 6" REPAIR COUPLING
5" X 7" TUB SPOUT
5" x 8" FLEX ALUMINUM DUCT
20 oz. Great Stuff Big Gap Filler
JB Weld
Toggle Bolts 3/8" X 4"
Great Stuff Insulating Foam
Heavy Duty All-Purpose Grease
Screws
Washers
48 in. Pink Spherachute
60 in. Pink Spherachute
3 PK. FIBER ARROWS
1/2" X 1/2" x 36" BALSA STOCK
3/8" X 6" X 36" Balsa
38 in. tube
16 Oz. Great Stuff Crack Filler
TOFFE POPCORN
36 IN POOL TUBE
Price
Table 3: Budget
36
Quantity
Shipping Total
0.99
5.99
5.99
8.99
9.99
17.99
24
3
1
1
1
1
23.76
17.97
5.99
8.99
9.99
17.99
2.49
1
2.49
6.99
1
6.99
1.49
0.89
9.99
2.38
3.09
0.96
2.57
3.94
9.99
6.49
4.18
4.78
4.96
4.98
0.98
0.98
39.00
50.00
10.64
5.9575
7.59
4.99
3.98
3.99
2.99
1
1
1
2
1
1
1
1
2
4
1
1
1
1
8
30
1
1
1
4
2
1.49
0.89
9.99
4.76
3.09
0.96
2.57
3.94
19.98
25.96
4.18
4.78
4.96
4.98
0.98
0.98
55.00
50.00
10.64
23.83
15.18
4.99
19.90
3.99
2.99
5
1
1
16
The following is a break down of divisional labor amongst the High Altitude Balloon Team:





4
Jade O’Mara is a Senior Mechanical Engineering major on the High Altitude Balloon
Team Chutes and Giggles. During both terms, Jade was involved by contributing ideals
for the parachute launch and assisted in manufacturability of the ballute. During launch,
Jade was involved in filling and tying off the balloon in preparation to attach to the
package.
Alleyce Watts is a Senior Mechanical Engineering major on the High Altitude Balloon
Team Chutes and Giggles. During both terms, Alleyce was involved in helping to
develop and build the ballute and control package. She was also in charge of flight path
prediction and communication to the FAA and local airports prior to and during the
launch.
Adam Blake is is a Senior Mechanical Engineering major on the High Altitude Balloon
Team Chutes and Giggles. During both terms, Adam was involved in helping to develop
the ballute and control package. Adam was involved with fabrication of the ―Wright
Device.‖
Eddie McGovern is a Senior Mechanical Engineering major on the High Altitude Balloon
Team Chutes and Giggles. Eddie was the primary designer of the ballute structure and
was also in charge of the balloon filling during the launch.
Ryan Vogel is a Senior Mechanical Engineering major on the High Altitude Balloon
Team Chutes and Giggles. Ryan was involved with the development of the ballute as
well as the control box. Ryan was primarily involved with release mechanisms between
the ballute and control box and was largely a part of the APRS tracking on launch day.
REFERENCES
Cengel, Yunas A., and Michael A. Boles. Thermodynamics: An Engineering Approach.
4th ed. New York, New York: The McGraw-Hill Company, 2002.
"Electronic Code of Federal Regulations." 27 July 2005. National Archives and Records
Administration.10 Oct. 2005
<http://ecfr.gpoaccess.gov/cgi/t/text/textidx?c=ecfr&sid=e2c906490f4ce4ab73256388a21
8eb0d&rgn=div5&view=text&node=14:2.01.3.15&idno=14>.(n.d.).
Members, H. (2011, January 6). www.cs.wright.edu/balloon/index.php/Downloads. Retrieved
March 7, 2011, from www.cs.wright.edu/balloon/index.php/Main_Page:
www.cs.wright.edu/balloon/index.php/Main_Page
37
NASA. (2010, August 18). Terminal Velocity. Retrieved from NASA:
http://www.grc.nasa.gov/WWW/K-12/airplane/termv.html
Near Space Systems, Inc., dba Global Near Space Services © 2006-2010 10 Febraury 2011
<http://www.nearspacesystems.com/definition.shtml>.
"U.S. Standard Atmosphere 1976." United States Committee on Extension. 05 Oct.
2005 <http://modelweb.gsfc.nasa.gov/atmos/us_standard.html>.
Wright State University High Altitude balloon Team. 16 January
2011<http://www.cs.wright.edu/balloon/index.php/Main_Page>.
5
APPENDICES
Part Checklist
□ Ground cloth/tarp and stakes
□ Balloon enclosure and Velcro break-away strap
□ Weights for ground cloth (water jugs)
□ Table
□ Handling gloves (latex gloves)
□ Helium (in secure transport structure)
o Take 3 tanks for 1500 gram balloon
□ Helium regulator
□ Flow meter
□ Flashlights
□ Scientific scale (not fish scale)
□ Fish scale/counterweight
□ Bucket to fill with sand
38
□ Balloons (3 balloons total = 1 for flight, 1 for burst, 1 for fly-away)
□ Nichrome wire
□ Nichrome wire circuits
□ Parachute
□ Pink nylon cord
□ Payload harness (orange color)
□ Water bottle with soapy water
□ Carabineers
□ Barnes Balloon Attachment Connector/Ring
□ Radar reflector
□ Handheld GPS tracker
□ Notebook and pen
□ AC Inverter
□ Mobile HAM (with car battery)
□ directional antennae
□ ham radios used with directional antennae
□ AA batteries for directional antenna radios
□ Cigarette lighter plug
□ FRS Walkie-Talkies (for foxhunting)
□ AAA batteries for walkie-talkies
□ Smoke dectector
□ Cigarette lighter plug
□ Spreader Ring
□ Swivels (at least 3)
□ Extra Balsa Wood
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□ Fishing Line
□ Extra snaps
□ Extra springs
□ Extra nuts
□ Extra ―I‖ hooks
□ Balloon connection
Laptop
o Power cable
o Floppy drive
o CD-ROM drive
o Drive cable
o HAM
PC cable
o USB flash drive
□ Communication module
o GPS receiver
o GPS antenna
o Battery pack (for GPS)
o Handheld HAM radio with battery pack
o HAM antenna
o Screamer circuit
o 9V battery for screamer
o ―SOS‖ foxhunting beacon
o Camera
o Box lid
o Nylon bag
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o Bag label card – harmless radio device; contact info
o hand warmers
o carabineers to attach to bottom of command module
□ Tool kit
o Multimeter
o Screwdrivers
o Pliers
o Wire cutters
o Wire
o Electrical tape
o Duct tape (black)
o Gorilla tape
o 2 large adjustable crescent wrenches
o Measuring tape
o Soldering iron
o Solder
o Solder wick
o Spare AA batteries
o Battery charger????????????
o Spare 9V batteries
o Spare 3V batteries
o Zip ties
o Kite string
o Pocketknife
o Scissors
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o Extra batter terminal leads
o Stop watch
o Tackle box
o Allen Wrenches
o Extra carabineers
o Wax
□ Documents
o Tax exempt form
o Phone numbers (launch site and area approaches)
o Directions to launch site (enough for all drivers)
o Directions from launch site to landing site (enough for all drivers)
□ In-Box
o Servo unit
o ―Ohio‖ Device
o DTMF Board
o Camera
o APRS
o LED Light
o Pull Pin Device
o Battery Pack (insulated)
o Nichrome boards
o Beacon/Screamer **
o Data logger **
** Power on as close to launch as possible
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Accelerometer Data
43
44
45