JET PULSE DRONE
F13-59-PULS
Saluki Engineering Company
Southern Illinois University Carbondale
Mechanical Engineering and Energy Process
John Hamburg (PM)
jhamburg@siu.edu
Matthew Benes
mattbenes@siu.edu
Michael Godinho
mgodinho@siu.edu
Kyle Goetzelmann
kgoetzel@siu.edu
David Morris
dawillmo@siu.edu
Eileen Schwiess
eschwiess@siu.edu
Faculty Technical Advisor: Kanchan Mondal
Transmittal Letter (KG)
November 21, 2013
Saluki Engineering Company
Southern Illinois University Carbondale
College of Engineering – Mail Code 6603
Carbondale, IL 62901
Dr. Mathias
Mechanical Engineering and Energy Processes
Southern Illinois University Carbondale
Carbondale, IL 62901
Dear Dr. Mathias:
On behalf of the Saluki Engineering team, I would like to thank you for including us in
the bid for the project for a fuel efficient pulse jet engine. Attached is a proposal for a design that
implements an effective throttling system as well as an overall engine that meets the criteria
desired by new, cutting edge, unmanned drones. We would like to thank you for giving us the
opportunity to bid on this project and we are grateful for your interest in our engine’s design.
Our method of designing a pulse jet engine that outperforms others comes from the
proposed throttling system aimed to keep fuel consumption to a minimum while still offering full
power. Every effort is being made to keep the design simple and reliable. Through effective
designing this engine will compete with other power systems in its size class while maintaining
its cost advantage.
Through research and testing of existing aircraft airframes/power systems, we have
attained what we think to be realistic and optimal performance goals for our engine. We thank
you again for the chance to bid our design on the project. We look forward to collaborating with
you in the design process to create a new and exciting product for unmanned drone enthusiasts.
If there are any concerns or questions regarding the attached documents please feel free to
contact me.
Sincerely,
John Hamburg
Project Manager
F13-59-PULS
Saluki Engineering Company
(708) 275-6580
jhamburg430@siu.edu
2
TABLE OF CONTENTS
Executive summary ........................................................................................................................................................... 5
1 Introduction ...................................................................................................................................................................... 7
2 Literature review............................................................................................................................................................ 7
2.1 Market Research of Comparable Power Systems [KG] .................................................................7
2.2 Engine............................................................................................................................................................. 10
2.2.1 Engine Materials [JH] ...................................................................................................................... 10
2.2.2 Thrust Augmentation ...................................................................................................................... 13
2.2.3 Combustion Chamber [DM] ............................................................................................................... 13
2.2.4 Fuel System [MG] ................................................................................................................................... 13
2.2.5 Valves [ES] ................................................................................................................................................ 16
2.2.6 Electrical Components [MB]......................................................................................................... 19
2.3 Design Procedure (KG)............................................................................................................................ 21
2.4 Codes and Standards [MB] [JH] ........................................................................................................... 22
2.5 Summary of Reviewed Literature [JH] ............................................................................................................23
3.1 Project Description [KG] ........................................................................................................................................23
4 Design Basis [MB].........................................................................................................................................................25
5.4.1 Fuel Containment and Delivery [KG] ............................................................................................................27
5.4.2 Fuel Types [MG] .....................................................................................................................................................28
6 Project Organization [MB] ........................................................................................................................................30
7 Action Item List [JH] ....................................................................................................................................................30
8 Timeline [JH] ..................................................................................................................................................................31
9 Resources Needed [MG] ............................................................................................................................................32
10 Data Analyses and Simulations to be performed [MG]..............................................................................32
11 Description of what is to be built [ES][MB] ....................................................................................................34
13 References ......................................................................................................................................................................35
14 Appendix: Personnel Resumes ............................................................................................................................38
Figure 1 Thrust vs. Cost/Lb Thrust for different power systems.................................................................. 9
Figure 2 Stress vs Rupture-Time and Creep-Rate Curves for Annealed type 316 Stainless Steel
[2] ............................................................................................................................................................................................11
Figure 3 Linear Thermal Expansion of the Three Main Classes of Stainless Steel [2] ........................12
Figure 4: Reed valves with damaged tips from overlap with valve plate [16] ......................................17
3
Figure 5: Standard shape for valve-less pulse jet engines ..............................................................................18
Figure 6 [12] Telemetry Block Diagram for airborne system ............................................................................19
Figure 7: Block Diagram ................................................................................................................................................24
Figure 8: Block Diagram Reference ..........................................................................................................................28
Figure 9 [12] Telemetry Block Diagram for airborne system ............................................................................29
Figure 10: Project Organization .................................................................................................................................30
Table 1 Thrust Comparisons of Propulsion Systems .......................................................................................... 8
Table 2 Properties of Selected Material [2] [33] [34]...........................................................................................10
Table 3 Basic Properties for Selected fuels [23][25][26][27]..........................................................................15
Table 4 (Properties of commercial RC Telemetry Systems)[13][37][36] ......................................................20
Table 5 (Battery specifications) [35]...........................................................................................................................21
Table 6: List of Documents ...........................................................................................................................................25
Table 7: Action Item List ...............................................................................................................................................31
Table 8: Timeline Spring 2014 ...................................................................................................................................31
Table 9: Parts List [JH] ..................................................................................................................................................33
Table 10: Parts List Continued ...................................................................................................................................33
4
Executive summary
Pulse jet engines differ from traditional jet engines in that they do not make use of any
turbines or compressors. Instead they rely on inertia of moving gases to achieve their relatively
small compression ratios. The lack of turbines and compressors makes the design of pulse jet
engines relatively simplistic, with few or no moving parts.
The proposed new pulse jet engine will feature a valve less design utilizing rear-facing
air intakes. Having the intakes face the same direction as the exhaust means that any expanding
gases that escape through the intakes during combustion will add to the total thrust produced
by the engine. This allows the engine to forgo the use of reed valves which struggle to hold up to
the conditions inside the combustion chamber and end up severely shortening the useful life of
the engine. The engine will achieve greater efficiency through the use of a throttling device
which will allow the engine to use less fuel when performance is not as essential. Research and
possibly simulations will be used to allow the engine to run as smoothly and efficiently as
possible. The proposed engine will also utilize temperature and flow sensors used in
conjunction with a telemetry system to provide real time feedback on engine and plane
performance.
The project is expected to be complete by March 31, 2014, allowing for several weeks of
testing and tuning after completion. The total cost of the project is expected to be no more
$1,000.00. This cost depends on the prices of components such as the material cost of stainless
steel for the engine body, which is subject to change.
5
RESTRICTION ON DISCLOSURE OF INFORMATION
The information provided in or for this proposal is the confidential, proprietary
property of the Saluki Engineering Company of Carbondale, Illinois, USA. Such
information may be used solely by the party to whom this proposal has been
submitted by Saluki Engineering Company and solely for the purpose of evaluating
this proposal. The submittal of this proposal confers no right in, or license to use, or
right to disclose to others for any purpose, the subject matter, or such information
and data, nor confers the right to reproduce, or offer such information for sale. All
drawings, specifications, and other writings supplied with this proposal are to be
returned to Saluki Engineering Company promptly upon request. The use of this
information, other than for the purpose of evaluating this proposal, is subject to the
terms of an agreement under which services are to be performed pursuant to this
proposal.
6
1 Introduction
This is the proposed design of a custom built jet pulse engine that will be used to power
a drone. The engineers involved will be responsible for building the engine and creating
interface to the RC drone. A camera will be mounted for reconnaissance and to aid in flight. The
engineers will aim to decrease the fuel consumption of the jet pulse engine to allow for
increased flight time and usefulness.
This proposal features a literature review, an overall project description, the design
basis and a description of deliverables for each subsystem of the engine. Also included are the
project organization chart, an action item list, a team timeline, and a list of required resources.
2 Literature review
2.1 Market Research of Comparable Power Systems [KG]
There are many power systems to consider for drone sized aerial vehicles. Possible options
include an electric ducted fan, kerosene powered turbine, or a pulse jet engine; each system has inherent
strengths and weaknesses as well as cost benefits based on the desired amount of thrust.
Electric ducted fans are typically powered by a 3 phase brushless motor inside a fan assembly
spinning a fan blade at high RPMs. These types of electric power systems produce less thrust per given
amount of power than their propeller counterparts; however, the exhaust air leaving the fan assembly is
at a much higher velocity making them ideal for more aerodynamically designed airframes. The cost
advantage of electric ducted fans occurs at a larger variety of thrust ranges. For example, to make a
drone with an electric ducted fan the cost per pound of thrust is fairly constant; this means the cost to
scale up the system to get more thrust is linear.
Kerosene powered turbines are the combustion equivalent to electric ducted fans taking in large
quantities of air and compressing it. Kerosene fuel is added to the compressed air and the mixture is
ignited expanding the gases. The compressed gases entering forces the expanding out as exhaust creating
thrust. Here it passes through a turbine which powers the compressor at the front of the engine via a
direct shaft which takes in more air and the process is then self-sustaining. The more fuel that is added,
the greater the combustion and more gases are forced out the back of the turbine as thrust. These engines
can be fairly effective, producing over 20 lbs of thrust on an engine that weighs less than two pounds
[28]. There is however a cost disadvantage with turbine engines. The smallest turbine produced by
JetCat USA produces 5.5 lbs of thrust. This engine costs nearly $3000 [2], almost five times as much
as an electric ducted fan of equivalent thrust. Up until about 20 lbs of thrust, turbine engines get more
cost efficient the more thrust they generate. At the 20 lb thrust range, they are almost the same price as
electric ducted fans of equivalent thrust.
Pulse Jet engines operate a little differently than the previously mentioned power systems.
There are two different types of pulse jet engines: valved and valveless. Valveless pulse jet engines rely
on two pressurized wave fronts generated from combustion. One wave front exits the longer exhaust
tube and the other out of the shorter intake tubes. By properly tuning these engines through proper
geometry, a resonating combustion process can be achieved. In a valved pulse jet engine, there are
valves in the inlet that control the air entering the engine. As air is drawn into the engine, low pressure
is generated which also draws in fuel. This mixture passes through the valve system and vaporizes then
7
combusts. This creates a high pressure system which closes the valves. Exhaust then shoots out the back
which causes a vacuum in the tailpipe. This opens up the valves and the process continues. Valveless
designs are a little less efficient and therefore need a slightly bigger engine to produce similar thrust
[32]. They are a lot less complex though which makes them more popular. These engines will run on
almost any type of flammable fuel. There is no company that makes these engines specifically for
hobbyists, so cost/thrust analysis is hard to come by. A lot of the pulse jet engines are homemade and
can be made relatively inexpensively if you are handy with a welder and are an experienced builder.
This is what generates the appeal of the pulse jet engine for hobbyists making larger airplanes. They can
possibly be more cost effective than the previous two mentioned power systems.
Table 1 contains statistics relating the three different engine types. Information on large scale
pulse jets was limited and therefore omitted. The table still serves as a valuable comparison tool for the
power systems used.
Table 1 Thrust Comparisons of Propulsion Systems
Type of propulsion
3 Lb Thrust Range
Electric
Ducted
Fan
Turbine
Pulse Jet
10 Lb Thrust Range
Electric
Ducted
Fan
Turbine
Pulse Jet
20 Lb Thrust Range
Electric
Ducted
Fan
Turbine
Pulse Jet
Lbs of Total
thrust
Cost
Cost/Lb
Thrust
Manufacturer
Runtime
(min)
Power
Source
3.08[27]
$310.00
$100.00
Mercury
4
Electric
5.5[28]
3[29]
$2,800.00
$200.00
$510.00
$66.67
JetCat USA
Homemade
3 fl oz/min
Unknown
Kerosene
Varies
8.5[30]
$427.00
$50.20
Medusa
3
Electric
13[28]
$2,395.00
$184.00
JetCat USA
Homemade
8 fl oz/min
Unknown
Kerosene
Varies
18.5[31]
$950.00
$51.35
Scorpion
3
Electric
22[28]
$2,195.00
$100.00
JetCat USA
Homemade
9 fl oz/min
Unknown
Kerosene
Varies
8
Thrust vs. Cost/Lb Thrust
Electric Ducted Fan
$600.00
Turbine
Cost/Lb Thrust ($)
$500.00
$400.00
$300.00
$200.00
$100.00
$0.00
0
5
10
15
20
25
Thrust (lbs)
Figure 1 Thrust vs. Cost/Lb Thrust for different power systems
9
2.2 Engine
2.2.1 Engine Materials [JH]
Since the very first prototypes of pulse jet engines, steel has been the metal chosen to endure
the extreme conditions resulting from the explosive fuel and air mixture [1]. To ensure both mechanical
function and safety as a jet engine that will power a drone for hobbyists, the following criteria must be
considered: the melting point, Thermal Expansion Coefficient, ‘creep,’ cost, weight and corrosion must
all be considered; Table 2 shows these properties for selected materials.
Table 2 Properties of Selected Material [2] [33] [34]
Metal
Melting
Temperature (°C)
Cost (dollars/lb)
Stainless Steel
1510
0.4-0.45
Steel (Mild)
Density (kg/m^3)
TEC
7480-8000
0.2-
9.9-17.3
7850
13
1425-1540
0.4
Titanium
1670
9.27-16.8
4500
8.6
Aluminum
660
0.47-1.0
2712
2.22
As the engine comprises a significant amount of weight in any aeronautical vehicle, material
selection becomes a critical element as the engine must propel its own weight as well as the weight of
the plane into flight. Three factors determine the weight of the engine: density, material gauge,
geometric dimensions (length and diameter); all of which are variable-dependent. The engine
dimensions and fuel selection determine maximum internal pressure and temperature. Material type and
thus density are determined upon maximum temperature reached, while gauge size is based upon
maximum temperature and internal pressure. Each factor is based on functionality, desired engine
performance, and lifespan. Gauge sizes for pulse-jet powered RC planes can range from approximately
11 gauge to 22 gauge steel of various types [3].
With combustion chamber temperatures recorded as high as 1426.85°C during experimental
testing, mechanical failure becomes a serious concern [4]. As a metal approaches the melting point, its
mechanical properties diminish significantly. Eventually, the yield point will reduce to zero and the
solid metal becomes a fluid; however, as the engine experiences internal pressure from the expanding
gases, rupture would occur before the solid metal can liquefy [4]. Rupture-time is based on temperature
and stress, varying for each material type. (See Figure 2 [4] for the Stress versus Rupture-Time of 316
Stainless Steel. This factor constrains the material selection process to metals having a boiling point
above the recorded 1426.85°C.
10
‘Creep’ is the permanent deformation of a material below the yield point, and occurs under
applied loads for extended periods of time [5]. According to the ASME Boiler and Pressure Vessel Code
for high temperatures, 1% of ‘creep’ expansion is allowable for 100,000 hours of service [8]. Although
pulse jet engines do not follow the same standards, ‘Creep’ is particularly common at elevated
temperatures and, thus, becomes a critical factor for functionality, safety, and operational life (see Figure
2 for Stress Versus Rupture-Time and Creep-Rate Curves). Figure 2 demonstrates the effect temperature
has on the rupture-time of 316 Stainless Steel at a given pressure as well as the creep-rate in % ‘creep’
per hour at a given temperature. Stress Versus Rupture-Time and Creep-Rate Curves are established
from experimentation and available for all metal types [4].
Figure 2 Stress vs Rupture-Time and CreepRate Curves for Annealed type 316 Stainless
Steel [2]
Regarding the physical design, the thermal expansion coefficient (TEC) will affect tolerance
specifications based upon changes in diameter and length.
L = length, α = TEC , T = temperature
ΔL = α ∗ Lo ∗ dT
Do = original diameter, Di = new diameter
𝐷𝑖 = 𝐷𝑜 ∗ (𝑑𝑇 ∗ 𝛼 + 1)
11
Extensive changes in length and diameter can result in failure of the brackets and mounts, as
well as the functionality of the engine itself. Additionally, if different materials are joined, tolerances
must accommodate as the materials will expand at different rates to different sizes (including any
instrumentation attached). For example, a Martensitic steel may be used to construct the combustion
chamber and exhaust of the engine while an Austenitic steel is used for the mounting brackets, perhaps
for weight. The difference between the TEC of each metal (see Figure 3) would result in different
expansion rates between the brackets and engine [4]. If enough tolerance (gap) is not left to
accommodate the change in expansion between the two parts, failure will occur. Figure 4 displays the
linear correlation between the TEC and temperature of the main classes of Stainless Steel; Austenitic,
Martensitic, and Ferritic Grades.
As the metal expands at these elevated temperatures, they become increasingly susceptible to
corrosion [6]. Particularly in an environment with exponential quantities of air and gases passing
through, oxidation occurs at a rapid rate resulting in deterioration of the metal and its mechanical and
thermal properties. Although longer lasting solutions are available; addition of Chromium and/or
Molybdenum in the manufacturing of steel, for simplicity and scope of this project, corrosion and
oxidation resistant coatings can cost effectively solve this problem, rendering it obsolete for further
review [7].
Figure 3 Linear Thermal Expansion of the Three Main
Classes of Stainless Steel [2]
Based upon clientele needs and budget, cost becomes the final factor in material
selection. Although a metal such as titanium may exhibit superior mechanical properties, becoming
the primary choice in harsh environment applications, the average hobbyist may not require the same
performance standards. Hence, a less expensive metal may be selected to accommodate the client’s
budget.
12
2.2.2 Thrust Augmentation
Several methods of thrust augmentation have been implemented in the design of jet engines for
some time. Essentially, with the desire for higher thrust output, mass is added to the exhaust gases
increasing the total mass flow. Following Newton’s third law of motion, the additional mass in the
exhaust gases generates a larger reaction force on the engine, increasing thrust. The injection of air, fuel,
water and oxidizers, are various additions of mass each resulting in different changes in overall thrust
output. Depending upon engine demands for thrust output, fuel efficiency, and the overall speed of the
aircraft, thrust augmentation becomes a viable option during the design phase.
2.2.3 Combustion Chamber [DM]
The combustion chamber in a pulse jet engine is different from the combustion chambers of
more common engines, such as the standard turbine jet engine or the piston engine. In a valveless pulse
jet engine, the combustion takes place throughout the whole engine; if it is a valved design, combustion
is everywhere behind the valves [10]. Generally, the section before the tail pipe where the air and fuel
are taken in and mixed is considered the combustion chamber. The main purpose of this combustion
chamber is to provide a place to get a balanced air and fuel mixture. In existing pulse jet engines, such
as the Argus V1 design used by the Germans in World War 2, this was done by injecting fuel directly
into the combustion chamber near the air intake [11]. When a pulse jet engine reaches its equilibrium
running temperature, the high temperature also helps to evaporate the fuel and promote better mixing
[10]. The combustion chamber directs the expanding air and fuel mixture to create thrust in the desired
direction. In valved pulse jet engines, one-way valves are used to make sure air can only escape in the
desired direction, while in valveless designs, the intake is typically directed the same way as the exhaust,
so any air escaping through the intake is added to the thrust of the engine [9].
Starting a pulse jet engine is a bit more challenging than most engines. During normal running
conditions, pulse jet engines rely on the burning gases exiting through the exhaust pipe to create a
negative gauge pressure in the combustion chamber which pulls intake air into the engine; the burning
exhaust gases also light the next volume of air fuel mixture [9]. Hence, starting a pulse jet engine will
require outside sources to supply both the pressure gradient between the air intake and the combustion
chamber, and also a flame source. The intake air pressure gradient is generally supplied by an air
compressor or blower while the flame source is usually provided by a spark or glow plug, or sometimes
from a torch or sparkler held in the combustion chamber. This process makes the normal starting
sequence for a pulse jet engine simply a matter of turning on the fuel and ignition systems while blowing
air through the intake. Once the engine has started, the ignition system and compressed air are
unnecessary for the engine to run properly [10]. Pulse jet engines, such as the Argus V1, are ignited by
with a highly flammable fuel, such as acetylene which was used in the Argus V1, to activate the engine
before switching to the fuel used during normal engine operation [11].
2.2.4 Fuel System [MG]
The fuel system for a drone consists of several key features: the fuel, the fuel tank, the fuel
pump and the fuel injection. The placement and the weight of these components are extremely important
as they can affect weight distribution, stability and flight time.
13
2.2.4.1 Fuel
The efficiency, the flash point, the burn temperature must be considered in determining the type
of fuel to use for the aircraft. The difference in the weights of several fuels is negligible, due to the small
scale of the project, but can easily range from one to two pounds, depending on the desired storage
capacity and flight time. From previous experiments conducted, the temperature of the burning fuels is
difficult to calculate but have been recorded to be in the range of 1500 °F to 2000 °F [25].
The efficiencies of the fuels depend upon how fast the fuel will flow and burn through the
system. The rate of expansion when the fuels are ignited is a significant factor when considering the
efficiencies of different types of fuel. In many cases, these results are determined through testing the
fuel in the system that it is being considered this procedure is normally done in scaled down versions.
The flash point (FP) of a fuel is the temperature at which the fuel may sustain continuous
combustion. The FP should not be mistaken for the Auto-Ignition Temperature (AIT), which is the
ambient temperature at which the fuel with spontaneously combust.[19] The main reason for
considering the FPs of different fuels is the ease of ignition; less effort would be required to start the
engine if the FP is low. When a higher temperature is needed to ignite the fuel, more advanced
equipment may be necessary to deal with the higher temperature.
In the case of AIT, the higher the temperature the safer the fuel source, especially if the source
is placed close to other components that may emit high temperatures, such as the engine. If the AIT is
low the craft may explode during flight.
A low FP and high AIT is ideal. Typical fuels used in model pulse jet drones are shown in
Table 3.4.1 along with their FPs and AITs. As the numbers suggest, FPs and AITs do not seem to be
related. However, the amount of energy and the rate of expansion of each type are different. These
differences have to deal with the chemical makeup of each substance, which also affects the amount of
energy that is released during combustion. It is a combination of these three factors that will need to be
taken into consideration.
In small scale craft it is typical to see a flight time between two to four and a half minutes on a
tank of about 32 ounces. This is dependent on the types of fuel used. Most hobbyists have determined,
through trial and error, that mixtures of different fuels can provide the best propulsion, most often trying
to take the best properties of each type. Also listed in Table 3.4.1 are the current prices and approximate
thrust based on the test results of a small scale pulse jet rated at an average thrust of 7lbs.
14
Table 3 Basic Properties for Selected fuels [23][25][26][27]
Fuel
Flash
Point
(F)
AutoIgnition
Temp (F)
$$$/Gallon
Energy
Density
(BTU/lb.)
Gasoline
Kerosene
Propane
Ethyl
Alcohol
Methyl
Alcohol
JP-8
-45
100-162
-156
55
536
563
878
689
3.50
3.68
3.50
3.68
14,703
18,610
-11,522
Approx
Max
Thrust
(lb.)
5.5
6
4
6.8
52
878
2.38
8555
8.2
60
410
3.75
18,800
--
When determining the type of fuel necessary it is advised that several static tests must be
conducted. Creating a perfect mixture of fuels requires extreme care but can result in a very efficient
and powerful fuel type.
2.2.4.2 Tank
Fuel tanks add considerable weight to the aircraft and require careful consideration. The
material of the tank can affect the center gravity which could make flying very unstable. Types of fuel
tanks that have been used are plasma bags (the same kind used to carry blood), plastic tanks that are
formed into the compartment (these may be the most common), and aluminum tanks (most common for
pressurized fuels). The size and type of the tank is dependent upon the type of fuel and the desired flight
time.
Plasma bags may be extremely useful as their weight is minimal and the quantity of fuel they
hold is reasonable (approximately 1 Liter). If they are secured properly, As fuel drains from the bags, ,
less “sloshing” will occur as the aircraft engages in maneuvers. The bags are also easy to store for on
the planes as they can be compressed. The use of these types of fuel storage may only be reasonable on
small scale craft. The larger the vehicle, the more fuel will be required and the bags will not be suitable
to easily hold the fluids.
Metal tanks on small crafts are rare, as their weight is detrimental to the plane. Although this
type of tank is more easily pressurized to allow better flow, they are unsuited to be used on small scale
planes. However; they are more common when dealing with much larger craft as they can hold a sizeable
amount of fuel and can sustain flight for long periods.
A plastic tank is the most commonly used fuel storage for hobbyists and other small scale
models. They are inexpensive, can be custom fitted and are relatively lightweight. Additionally the
plastic containers can hold a multitude of different fuels. Their drawback is that they cannot be as
pressurized as metallic tanks. A similar drawback exists in the plasma bags.
Location is a major consideration when designing the fuel system. If the tank is close to the
engine and the fuel has a low flash point, spontaneous combustion may occur in flight. In the case where
the tank is farther away the fuel may have trouble flowing to the engine during high g turns. Typically,
15
the fuel is stored in the fuselage of the plane directly inform of the engine. In the case of single wing
aircraft designs, such as the delta wing, the fuel tank tends to be set in the wings themselves, although
close to the center.[21]
2.2.4.3 Pump and Injection
Most injection and pump systems are very similar when dealing with small scale models. In
most cases, a pump is not even necessary, as the pressure from the combustion will draw the fuel out of
the tank [see combustion chamber]. The necessity of the pump comes into to play when dealing with
larger fuel reserves as the amount of fuel in the tank may require more pressure to be moved; this
scenario may be avoided by the placement of the hose that will lead from the tank to the engine.
The injection of the fuel into the engine should be placed very carefully. If the fuel line is set
in the wrong location the fuel will not be able to ignite and flood the engine, combust too early and
damage the components, or simply not acquire the desired effect. The injection nozzle from the tank is
commonly placed in one of two places: radially (meaning from the side of the engine) and axially (from
the front). The oxygen is provided via the intake of atmospheric air. The heat from the combustion of
the gases, expands the air, along with the fuel, out of the tailpipe providing the thrust. [see combustion
chamber].
2.2.5 Valves [ES]
There are two common pulse jet types: valved and valve less. These different engine types
operate similarly, but the process by which air enters and leaves the combustion chamber is different.
2.2.5.1 Valved Engines
Valved pulse jets work using a single moving part: the reed valves, which open to allow air into
the combustion chamber, and close to prevent exhaust gases from exiting through the intake. [15] One
advantage of the valved style pulse jet is that as air flows inside the carburetor, fuel is drawn in to fill
the vacuum, and no fuel pump is needed. This decreases the complexity of the system for integration
into vehicles. Also, valved pulsejets tend to have a high power to weight ratio. [15]
There are many disadvantages to valved pulsejets, as they are difficult to start and are more
difficult to build. Additionally, the valves tend to wear out very quickly.
According to Bruce Simpson [16], the reed valves are the weakest link of the valved style.
Because they are slammed back and forth several hundred times per second, and are exposed to
extremely hot combustion gases. Simpson recommends keeping the valve movement to a minimum by
using a larger valve that has to move minimally to allow the necessary air into the chamber. The author
also advises that the valve plate be smooth to prevent stress concentrations. He continues to say that too
much overlap of valves to the valve plate will cause air to become trapped between and cause the valve
16
tips to bend backwards. Reed valves are a downfall to valved pulsejets because they have a very short
lifespan and need to be replaced frequently.
Figure 4: Reed valves with damaged tips from
overlap with valve plate [16]
To prevent hot combustion gases from reaching the valves, Simpson has experimented with the addition
of a “Blast Ring” which is a simple metal ring in the chamber that disrupts the back flow of gases
towards the valves. His research has shown this ring to be effective at keeping the valves cool and
extending their lives, however, it drastically reduces the power of the engine. He has also used a screen
mesh between the combustion area and the valves to accomplish the same goal, however this impedes
the engines power even more and tends to have a short lifespan. [16].
2.2.5.2 Valveless Engines
Valve less pulsejets are the other common type of pulse jet engines built today. According to
Simpson, the Lockwood-Hiller design was developed in the 1950s and 60s. In this type of pulse jet,
there are no moving parts. Air flows in and mixes with fuel, then is sparked by a spark plug in the
combustion chamber and explodes. Next, the exploding air fuel mixture expands out both ends of the
pipe, producing thrust. This creates a low pressure zone in the engine, and fresh air flows in. Most of
the air rushes in through the short intake pipe, but some air comes back through the exhaust, creating a
higher pressure zone in the engine that compresses the new air fuel mixture to start the next cycle. [16]
Due to the tendency for exhaust gasses to flow out of both the inlet and outlet of this engine, it is
typically shaped with the inlet facing the same direction as the exhaust, to make use of as much thrust
as possible.
17
Figure 5: Standard shape for valve-less pulse jet engines
William Deene, who submitted a patent regarding jet pulse engines in ultrasonic flight, he states
that a “number of ingenious valve less pulse jet engines have been designed in which changes in airflow
constitute a valve arrangement.” For his jet engine, he supports that flow separation at the jet nozzle can
be used in place of traditional valves. Since the outgoing pulse is at high velocity, directed mainly in
the direction of thrust, that momentum will preferentially leave the engine through the exhaust [17 p 16]
Research on valve less pulsejets has recently taken the spotlight at North Carolina State
University. Researchers have been working for various agencies who want to propel UAVs with an
efficient, affordable, and robust power source. They have been able to miniaturize the engine, making
pulse jets as small as 4 cm long, with modifications in engine geometry. They also were able to produce
an 8 cm long air breathing hydrogen fueled pulse jet [18].
The advantage to having such a simple design is that valve less pulse jets can be built in almost
any size and shape and still run. They are easy to start, consist of no moving parts and can run on almost
anything that burns. Unlike valved pulse jets, valve less jets have a very large throttle range, and can be
run for a virtually unlimited amount of time [17]. However, these advantages come at a cost.
Disadvantages of valve less pulsejets are numerous. They are Inefficient perform poorly, and
have a low thrust output [17]. Due to the need to point the inlet in the same direction as the exhaust,
they can also be very difficult to integrate into vehicles.
18
2.2.6 Electrical Components [MB]
2.2.6.1 Telemetry System for RC aircraft
Only a few existing systems are designed specifically for RC aircraft telemetry. Telemetry is
the process by which an object’s characteristics are measured (such as velocity of an aircraft), and the
results transmitted to a distant station where they are displayed, recorded, and analyzed [1]. Telemetry
is vital for remote aircraft because it allows users access to critical flight information that can be used
to monitor the performance of the aircraft as well as identify possible safety hazards. The key
components needed for a telemetry system are as follows: Sensors, microcomputers, RF
transmitters/receivers, data storage, graphical display, and analysis software.
Figure 6 [12] Telemetry Block Diagram for airborne system
The ideal telemetry system for aircraft applications would have the following features: Ability
to handle multiple sensor inputs, durable, long range RF transmitter; ability to store data on board, live
data stream to ground station, intuitive graphical interface, light weight, small size, and low cost. Preexisting RC telemetry systems will be compared based on the specifications.
The Seagull Pro Wireless Dashboard Flight System by Eagle Tree is a top of the line RC
telemetry system that has many advanced features including; Onboard data logging, small size(1.5 oz),
room for multiple sensor inputs, long range RF transmitter capable of upgrade, live stream to ground
display, USB to PC interface, and GPS flight mapping. This system is a complete package that includes
everything needed for an advanced RC telemetry system for aircraft. This system however is expensive
compared to simpler systems. [13]
19
Table 4 (Properties of commercial RC Telemetry Systems)[13][37][36]
System
Sensor
Input
Weight
(oz)
Size
(in)
Local
Storage
Interface
Range
(Miles)
Cost
Yes
Live
Data
Stream
Yes
Seagull
Pro
Wireless
Temp.
Airspeed,
Voltage,
Altitude,
Servo
1.5
3x2x1
PC and
Handheld
display
1.2
$499.99
Quanum
2.4Ghz
Telemetry
System
Voltage,
Current,
mAh,
Temp.
0.5
2x0.6
No
Yes
Handheld
Display
0.6
$49.99
Spektrum
TM1000
Custom
Temp,
Voltage,
As
Needed
0.5
1.7x1x0.5
Yes
Yes
0.1
$69.99
?
?
?
?
Mobile
Phone
Custom
?
?
2.2.6.2 Battery
Batteries are used to power the electronic components of RC aircraft because they are a simple
and reliable method of supplying the needed power to critical aircraft components such as control
servos, telemetry systems, and the on-board control unit. The different types of batteries used in RC
aplications will be examined and compared based on the following specifications: weight, voltage,
capacity, size, number of cells, and C-rating.
Three common types of batteries used in RC applications: Ni-Cd (Nickel Cadmium), Ni-Mh
(Nickel Metal Hydride), and Li-Po (Lithium Polymer). Ni-Cd batteries are inexpensive, however, they
are limited in performance, cycle life and runtime. Ni-Cd batteries can develop capacity problems if
they are not discharged completely. Ni-Cd batteries tend to lose performance when charged multiple
times in a single day. Ni-MH batteries to have improved performance and cycle life when compared to
Ni-Cd batteries. Ni-MH batteries have fewer capacity problem than Ni-Cd battery packs and can be run
multiple times in a day without a detrimental impact on the overall performance of the pack. They are
also more environmentally friendly and easier to dispose of. Li-Po batteries are a totally different design
and construction than Ni-MH or Ni-Cd batteries. Due to the average voltage of individual Li-Po cells
the overall voltage of a Li-Po battery will be higher than a comparable Ni-Cd or Ni-MH battery pack.
Li-Po batteries are also considerably lighter than their Ni-Cd or Ni-MH cousins. Li-Po batteries can be
run multiple times in a day without an appreciable reduction in performance or runtime. Li-Po batteries
do need to be charged with Li-Po specific chargers.[3]
Battery performance is given determined by its voltage and capacity, for LiPo batteries C-rating
is also important. The voltage of a battery pack is determined by the voltage of each individual cell and
how the cells are configured. Voltage often determines how much power can be delivered to the
electrical components. Capacity is measured in mAh (milliamp hours), the greater this number is the
longer the battery will last. C-rating Refers to the amperage output of a Li-Po battery pack. A higher Crating means the battery can handle more current when a load is attached.[3]
20
LiPo batteries are most commonly used because of their superior performance when compared
to NiCd and NiMh. Over all they can hold a charge longer and more consistently and do not degrade
overtime relative to NiCd and NiMh. Also the price differences are not great enough to justify lower
quality. For those reasons only LiPo batteries are compare in the following figure.
Table 5 (Battery specifications) [35]
Brand
Weight (g)
Dimensions
Voltage
C-rating
Cost
3.7
Capacity
(mAh)
2200
Turnigy
55
97 x 34 x 8mm
20
$3.91
Turnigy
58
99 x 34 x 8mm
3.7
2200
40
$5.75
Zippy
Turnigy
108
204
100x36x14mm
134x43x15mm
7.4
7.4
1800
3300
20
30
$8.25
$14.95
2.3 Design Procedure (KG)
The pulse jet drone has many systems that rely on each other and will change based on
the characteristics of the other systems. This suggested the use of an organized design procedure
to ensure all requirements were being met. There are three main systems on the pulse jet that are
inter-related: The fuel system, plane design, and engine design. Engine design will affect the
weight of the plane, which in turn will affect the power to weight ratio. Fuel selection can increase
thrust but depending on the fuel chosen, the containment system will weigh more and therefore
increase the weight of the plane.
The first thing to choose in the design process is the fuel selection. The fuel selection is
based off of the energy available in the fuel and how it will be contained on the plane. Once a
suitable fuel has been selected, the plane can be designed. Characteristics like flight performance,
payload capacity, and speed will all be taken into consideration. Flight characteristics and weights
of similarly sized electric planes will be used as a baseline for performance. That will provide
enough data to determine the empty weight, and target thrust to weight ratio of the plane. Once
the expected weight of the plane is determined, and engine can then be designed. The design of
the engine will have to provide enough thrust to adequately power the plane, without the engine
being too heavy as to change the expected weight. If the engine is too heavy, the plane will weigh
more and a new engine design will have to be made to deliver the new required thrust.
The design for the engine will be determined using thermodynamic and fluid calculations.
Combustion analysis will be used to determine the proper air to fuel ratio to create the desired
thrust. Once the mass quantity of air is determined, the inlet shape and size can be determined
more easily. The mass quantity of fuel will help to determine the proper fuel pumping and throttling
system. The same combustion analysis procedure for analyzing fuel ratio with be used for the
combustion chamber and exhaust tube design.
21
2.4 Codes and Standards [MB] [JH]
Small Unmanned Aircraft System Aviation Rulemaking Committee
Comprehensive Set of Recommendations for SUAS Regulatory Development
(1) Model Aircraft shall be flown in open spaces and in a manner that does not endanger the life
and property of others.
(2) Model Aircraft shall yield the right of way to all manned aircraft.
(3) Model Aircraft shall not interfere with operations and traffic patterns at airports, heliports,
and seaplane bases.
(4) Model Aircraft shall not be operated at locations where Model Aircraft activities are
prohibited.
(5) Model Aircraft are limited to unaided visual line-of-sight operations. The Model
Aircraft pilot must be able to see the aircraft throughout the entire flight well enough to maintain
control, know its location, and watch the airspace it is operating in for other air traffic. Unaided
visual line-of-sight does not preclude the use of prescribed corrective lenses.
(6) Model Aircraft shall be designed, equipped, maintained and/or operated in a manner in which
the aircraft remains within the intended area of flight during all operations.
(7) Model Aircraft pilots may not intentionally drop any object from a Model Aircraft that creates
a hazard to persons or property.
(8) Model Aircraft shall be operated in a manner that respects property rights and avoids the
direct overflight of individuals, vessels, vehicles, or structures.
(9) Model Aircraft shall not be operated in a careless or reckless manner.
(10) Model Aircraft pilots shall not operate their aircraft while under the influence of alcohol or
while using any drug that affects the person's faculties in any way contrary to safety.
(11) Model fixed-wing and rotorcraft aircraft shall not use metal-blade propellers.
(12) Model Aircraft shall not use gaseous boosts.
(13) Model Aircraft shall not use fuels containing tetranitronmethane or hydrazine.
(14) Model Aircraft shall not use turbine-powered engines (e.g., turbo-fan, turbo-jet) as a
propulsion source.
Currently the AMA (Academy of Model Aeronautics) is fighting the modification of the general
requirements for flying model aircrafts. The FAA (Federal Aviation Administration) modified the
requirements to line-of-sight flying ONLY, outlawing any model airplane not controlled by lineof-sight adjustments (video feed, preset flight plan, GPS, ect.) The bill making this modification
has passed in nine states thus far, but is still processing in others, potentially eliminating
hobbyists use of “drone like” model airplanes.
22
The Federal Communications Commission (FCC) Regulations for low-power non-licensed
Transmitter
The Federal Communications Commission (FCC) has rules to limit the potential for harmful
interference to licensed transmitters by low-power, non-licensed transmitters. In its regulations,
the FCC takes into account that different types of products that incorporate low-power
transmitters have different potentials for causing harmful interference. As a result, the FCC's
regulations are most restrictive on products that are most likely to cause harmful interference,
and less restrictive on those that are least likely to cause interference.
Although an operator does not have to obtain a license to use a Part 15 transmitter, the
transmitter itself is required to have an FCC authorization before it can be legally marketed in the
United States. This authorization requirement helps ensure that Part 15 transmitters comply with
the Commission's technical standards and, thus, are capable of being operated with little potential
for causing interference to authorized radio communications.
2.5 Summary of Reviewed Literature [JH]
The previous literature was reviewed to obtain the design knowledge required to build a
custom jet pulse engine for a remote controlled airplane. Aviation Technologies student, Ryan
Shupbach, experienced builder and enthusiast of model airplanes, will construct a RC powered
airplane modeled after a previous design of his. Ryan will construct the model plane from
fiberglass to strengthen his previous design to account for the additional weight of the pulse jet
engine, fuel, and telemetry system. Utilizing past experimentation from model airplane
enthusiasts, basic jet pulse engine concepts were implemented to determine the approximate size
and dimensions required to produce the thrust needed to power this custom RC airplane.
However, to fulfill the requested demand for greater fuel efficiency, design modifications will be
made to cater to this desire. The fuel type and exhaust geometry are two factors in particular
which have a drastic effect on the efficiency of the engine.
3.1 Project Description [KG]



Electronic Subsystem
o The electrical subsystem is crucial to the entire plane as it will allow certain
functions of the plane to be performed.
o The system will be responsible for monitoring temperature and air flow.
o The system will also assist in controlling the plane by changing the fuel flow via
the voltage in the pump and transmitting a first person view and airspeed to the
pilot.
Fuel delivery
o The fuel delivery system is the intermediate step between the fuel and the engine.
o It is comprised of a tank, fuel pump and valves.
o The pump can adjust the amount of fuel sent into the engine which will change
the rate of combustion, and therefore thrust and airspeed.
o The system must be resistant to corrosive substances because the fuel, and its
various compositions, may cause damage to parts in the system.
Fuel Type
o The fuel type directly affects the rate of combustion and the thrust
23
o
o

The flash point, the burn rate and the burn temperature can affect the way the
engine performs, and each need to be carefully considered as they could cause
damage to the material or the welds in the engine.
The corrosive qualities of the fuel can also cause damage to the fuel delivery
system, meaning that it should be monitored closely during operation.
Engine
o Intake- The intake of the engine will be carefully designed to allow for the proper
mass flow rate of air to enter the combustion chamber
o Combustion Chamber- The combustion chamber is where the reaction of fuel and
air will occur, and needs to be constructed strong enough to withstand the strong
reaction forces.
o Exhaust- The exhaust tube must be carefully designed to make the most use of
the exhaust gasses and create an efficient engine
3.1 Block Diagram [MG]—--Why is the label here??
Figure 7: Block Diagram
24
4 Design Basis [MB]
The basis of design work to be carried out by F13-59-PULS can be found in this list of
documents:
Table 6: List of Documents
Document
Block Diagram
Specifications
Design Proposal
Date Created
Oct-16, 2013
Oct-16, 2013
Nov-17, 2013
The Specifications describe various performance goals that were set for the pulse jet
drone. The total thrust output for the engine was determined by analyzing the thrust output of an
electric motor that was used to propel the original drone which was built by the aviation tech
student.. The size of the engine will be determined analytically by evaluating the air needed to
fuel the combustion at a rate to produce the required thrust. The range of the communications
systems will be determined by estimated flight range.
5 Subsystem Technical Discussions
5.1 Ignition System [DM]
The ignition system is necessary only to start the engine; once the engine is started,
combustion is achieved without an outside source. The ignition system needs to provide enough
heat energy to ignite the air/fuel mixture to initiate combustion. This will be done by placing the
spark source from a grill igniter in the combustion chamber where the air and fuel are mixed. This
spark plug can be tied into the electrical system of the plane and activated remotely.
The placement of the spark plug depends on the movement of the air/fuel mixture
through the combustion chamber. The circuitry depends on the electronics for the plane control
and telemetry systems. A circuit diagram of the ignition circuit will be included in the final report
as well as a data sheet of the components used. The design activities required for completing this
system include determining proper placement based on necessary parameters and using the onboard electrical system to implement the ignition system.
5.2 Intake/Exhaust [ES]
A valve less style of intake will be used for the air inlet to the combustion chamber. The
valved style jet engine has shown to be more fuel efficient, but the valves tend to wear and break
25
quickly, sometimes within seconds. The decision to use a valve less style engine was made on the
basis that the moving parts of the valve would be susceptible to failure, and would make the plane
unreliable in flight.
The air intake to the engine will be two tubes adjacent to the combustion chamber. The
opening of the intake will be located in the same direction as the exhaust. Since there will be no
valve to stop the flow of hot exhaust gasses towards the front of the engine, the reverse facing
intake chambers will maximize the thrust produced and allow for the most use to be made of
Throttling of the engine will be made using a flow valve to control the rate of fuel flow. Therefore,
the mass air flow of the air is a dependent variable, and cannot be controlled during flight.
The exhaust of the engine is critical for having a high efficiency. The proposed design will
feature a conical exhaust chamber that will increase in diameter the farther it moves from the
combustion chamber. This will allow for the most use of combustion gases. The walls of the
exhaust must be able to handle the high temperatures and pressures of the combustion products,
as well as resist corrosion.
The exhaust is a determining factor of the thrust produced and the efficiency. In the block
diagram, it can be seen that the exhaust is dependent on the throttling, and will create input to
the data collected block. It is critical to determine a nozzle shape that will fully utilize the energy
produced through combustion. FLUENT will be used to model airflow through the augmenter.
The elements which will define the subsystem design are the desired rate of combustion
and the size of combustion chamber.
The deliverables for the intake will be CAD drawings, and data calculations showing the
relationship of combustion to the velocity of the engine to demonstrate how dimensions for the
air intake were selected. FLUENT software will be used to analyze the air flow through the engine
shape. The pressure ratio will be used to specify a low pressure at the inlet in order to simulate
the airflow into the engine. An attempt will be made to do combustion analysis using FLUENT
software as well. Other necessary analysis processes will be performed using thermodynamic
principles.
The design activities required to produce the deliverables listed are a thermodynamic
calculation, using different mass flow rates of air to show what the resulting heat added to the
engine would be, and potentially the resulting thrust produced at such mass flow rate. This
calculation will have to be done with a fixed mass flow rate of fuel.
5.3 Combustion Chamber [DM]
In the combustion chamber, the air and fuel are brought into the engine. The design of
the combustion chamber must promote the mixing of the air and fuel to prepare for combustion.
This mixing is accomplished by injecting the fuel into the high velocity, turbulent air coming
through the air intakes. A hemispherical or pent roof shape will be used for the front of the
26
combustion chamber as these shapes have shown excellent properties to promote mixing of air
and fuel in popular engine designs. The combustion chamber must be appropriately sized so that
the right amount of air/fuel mixture comes into the engine to allow for complete combustion in
the engine allowing the expansion of the gases to provide thrust. This is accomplished by making
the combustion chamber volume about twenty percent of the total engine volume. The shape of
the combustion chamber must force as much of the expanding gases as possible to exit through
the back of the engine to create thrust. This task is accomplished by facing all openings to the
combustion chamber in that direction, so there is no other direction to go.
The combustion chamber relates to the size and placement of the intakes and exhaust,
which control the flow of the air that must mix with the fuel as well as the mass flow rate of the
air. The placement of the fuel injection determines where the fuel enters and how well the air and
fuel can mix. The placement of the spark plug will also affect how the flame propagates and how
the combusting gases will travel.
The final report will include a detailed diagram showing the exact dimensions of the
combustion chamber and the placements of the different components.
The design activities for the combustion chamber include calculating acceptable
dimensions based on needed parameters, and assembly.
5.4 Fuel System
5.4.1 Fuel Containment and Delivery [KG]
The fuel containment and delivery subsystem handles the storage of fuel on the drone as
well as the delivery of the fuel into the combustion chamber. The subsystem contains three
separate parts: the fuel tank, fuel pump, and injection nozzle. Several different ways of containing
and dispersing the fuel into the airstream exist.
Non Pressurized Fuel System (with fuel pump)
For smaller engines it is possible that the low pressure won’t be enough to draw in the
appropriate amount of fuel for efficient combustion. For this scenario a non-pressurized tank will
be used and a fuel pump will draw the fuel from the tank and through the injection nozzle into the
combustion chamber. The fuel pump has the ability to adjust flow rate which is how the engine
will be throttled. This system will allow for larger quantities of fuel to be drawn into the engine.
If through testing this method is found inadequate, other options such as those mentioned in the
literature review will be explored.
Fuel Nozzle:
The fuel containment scenarios need to inject fuel into the combustion chamber and will
be accomplished with an injection nozzle. The nozzle must be positioned and designed correctly
in order to properly mix the fuel with the air before it reaches the combustion chamber.
Fuel Subsystem and its relation to other subsystems:
27
As figure 8 illustrates, the fuel system, circled in red, affects the throttling which in turn effects
the thrust the engine produces.
Figure 8: Block Diagram Reference
5.4.2 Fuel Types [MG]
Thrust and flight time are the two main variables that will change. In flight, if the throttle
is fully opened then there will be an increase in thrust but a decrease in flight time. If the same
amount of thrust can be met with a different fuel at a lower flow rate, the fuel would increase the
efficiency. The following fuels fuel types have been used in previous pulse jets. The parts list
indicates the type of fuels most commonly used by hobbyists and by those in the aerospace
industry. The design will be designed with a common aviation fuel as the basis.
The fuel can be varied by changing its composition. Hydrocarbon based fuels will mix
together easily; hence combining different amounts of kerosene based fuels with gasoline will not
be difficult. Combining kerosene with gasoline will lower the flash point but increase the time it
takes to burn; this can also cause a viscosity loss in the fuel. Combining fuels with different flash
points is not a linear function and should be done carefully.
The type of fuel composition used affects the fuel delivery and containment system, as
well as the engine. The corrosive qualities of the fuels need to be taken into account as they could
damage the pump, valves, and hoses. In the engine, the temperature that the fuel burns could
cause damage to the welds or change certain properties in the metal.
5.2.5 Brackets/Mounts [MG]
Once the engine size is fully designed, brackets will be designed to mount the engine to
the aircraft. FEA analysis will be performed on the brackets to make sure they are adequate before
being integrated onto the plane.
28
5.2.6 Telemetry Systems [MB]
The pulse jet engine will be equipped with a wireless telemetry system that will be
capable of measuring vital engine data such as temperature and airspeed and transmitting the
data to a ground station to be analyzed. The system will be implemented using k-type temperature
sensors connected to the engine to read engine temperature, an airspeed sensor attached to the
aircraft frame, an Arduino Uno microcontroller, Xbee pro wireless communication module,
Arduino data logger, SD card, and a laptop PC with MatLab. The sensors will provide the Arduino
with analog signals that will be converted into digital format corresponding to airspeed and
temperature. Thermocouple temperature sensors have a low output voltage swing which makes
the output hard to read by itself. An amplifier circuit is needed to amplify the sensor output to a
useful level. The data will then be stored locally on board using the Arduino data logger and SD
card to insure data is recorded even if communication between the air and ground system fails.
The data will also be sent wirelessly using a 10Kbps serial communication link between two Xbee
pro wireless communication modules. The serial data will be transferred from the air to the
ground station where the data will be displayed in real time on the ground. The ground system
will use MatLab software to process, store, and display the live data stream. The data can then be
used to analyze the system performance by comparing the collected data.
Figure 9 [12] Telemetry Block Diagram for airborne system
5.2.8 Materials [JH]
The material for the engine shell (intake, exhaust, and combustion chamber) is required
to withstand the extreme temperatures and moderate pressures resulting from combustion. A
304 stainless steel has been selected and will be coated in one hundred percent pure 316 stainless
29
steel pigment to obtain the corrosion and oxidation resistant qualities of 316 stainless steel. After
multiple runs of the engine, the coating may need reapplication based upon inspection. The engine
intake, exhaust, and combustion chamber will be manufactured from various tubing sizes and wall
thickness as listed in the Parts List, Table 9.
To transition between the intake, exhaust, and combustion chamber, sheet metal will be
cut and welded to form gradual transition between each tube. These gradual transitions are
intended to reduce flow losses, maximize thrust, and improve fuel efficiency. Additionally, sheet
metal will also be used to produce a conically shaped exhaust, maximizing the velocity reached by
the expanding gases. If possible, tube reducers will be used in place of sheet metal to ease the
manufacturing process and reduce cost.
As Table 9 shows, the tubes and sheet metal will be purchased from a combination of
OnlineMetals.com and McMaster-Carr.com based on price and part availability. “Weld-ability” will
also become a factor when determining material selection. If parts are unable to be welded, a
larger wall thickness will be selected. Intake, exhaust, combustion chamber, and transitioning
pieces, will be dimensioned using CAD and aid in the manufacturing process.
6 Project Organization [MB]
John Hamburg (ME)
Project Manager
Matt Benes
(EE)
Electrical Systems
Kyle Goetzelmann
(ME)
Fuel Delivery
Mechanical Systems
John Hamburg
(ME)
Materials Selection
Eileen Schweiss
(ME)
Air flow analysis
Mike Godinho
(ME)
Fuel Selection
Figure 10: Project Organization
7 Action Item List [JH]
30
Table 7: Action Item List
Project: Jet Pulse Engine Powered Drone
Action Item List
Sec Ref #: S14-59-PULS
Date: 13-Jan-14
Team Members:
David Morris, ME (DM)
Matt Benes, ECE (MB)
Kyle Goetzelmann, ME (KG)
Eileen Schweiss, ME (ES)
Michael Godinho, ME (MG)
John Hamburg (PM), ME (JH)
#
Activity
Person
Assigned
Contact all members (set TM
1 date)
JH
7-Jan
Assign Design Report Tasks
JH
13-Jan
Design Subsystems
2 Design Combustion Chamber
DM/ES/JH
13-Jan
3 Design Intake
DM/ES/JH
20-Jan
4 Design Exhaust
DM/ES/JH
20-Jan
5 Design Fuel Delivery System
KG/MG
13-Jan
6 Design Ignition System
DM/MB
27-Jan
7 Design Telementry System
MB
13-Jan
8 Design Engine Brackets/Mounts MG
27-Jan
9 Order Parts
JH
20-Jan
Cut/Weld/Assemble Engine:
10 Shell
ALL-MB
27-Jan
11 Ignition System
MB/DM
3-Feb
12 Fuel System
KG/MG
3-Feb
13 Telemetry System
MB
27-Jan
14 1st Static Engine Test
ALL
3-Mar
Performance Modifications on:
15 Fuel Delivery System
10-Mar
8 Timeline [JH] KG/MG
16 Ignition System
DM/MB
10-Mar
Table 8: Timeline SpringDM/ES/JH
2014
17 Exhaust Length
10-Mar
18 Intake Length
DM/ES/JH
10-Mar
19 2nd Static Engine Test
17-Mar
SALL
chedule for S EC S 14-59-PULS
20 Perfect Fuel Type/Ratio
ALL
24-Mar
21Legend:
Integrate Engine with Drone
ALL
3-Mar
As bid:
As worked:
Added:
First Jet Pulse-Powered
Drone
Activity
22 Flight
ALL
31-Mar
23 Design Report tasks
ALL
13-Jan
27-Jan
3-Feb
10-Feb
17-Feb
24Activity
Oral Design13-Jan
Reports20-Jan
ALL
7-Apr
Due
New Due Status %
Comments
8-Jan
13-Jan
27-Jan
27-Jan
27-Jan
10-Feb
10-Feb
10-Feb
10-Feb
10-Feb
3-Mar
3-Mar
3-Mar
3-Mar
10-Mar
14-Apr
14-Apr
14-Apr
14-Apr
24-Mar
31-Mar
31-Mar
Deleted:
7-Apr
14-Apr
24-Feb
28-Apr
M ilestone:
3-M ar
10-M ar
17-M ar
24-M ar
31-M ar
7-Apr
14-Apr
Design Combustion
Chamber
Design Intake
Design Exhaust
Design Review
Design Fuel System
Design Ignition System
Design
Brackets/M ounts
Design Telemetry
Systems
Order Parts
M anufacture/Assemble
31
21-Apr
28-Apr
9 Resources Needed [MG]



Programs
o Microsoft Office Suite
o FEA
o Autodesk Inventor
o MATlab
Locations
o Machine Shop (Construction)
o Lab (Mixing fuels)
o Open field (testing and flying)
Tools
o Mill
o Plasma Cutter
o Welding Equipment
o Safety Equipment (Glasses and Ear protection)
o Laptop
10 Data Analyses and Simulations to be performed [MG]








CAD Renderings
Circuit and wiring diagrams
Thermodynamics and Combustion analysis
Bench-testing
Finite Element Analysis on the engine brackets
In-flight or simulated in-flight testing
Business plan based on prototype
Program microcontroller

Program MatLab

Connect electrical components/ mount in airframe

Calibrate Sensors

Deliverables
Troubleshoot/debug
 Electrical Schematic and Block Diagram
 Arduino Code
 MatLab Code
32
Table 9: Parts List [JH]
Table 10: Parts List Continued
33
11 Description of what is to be built [ES][MB]
A valve less pulse jet engine will be built to be used on a remote controlled air plane, which
will be constructed by a RC plane enthusiast. The engine will feature a reverse style of air intake,
a combustion chamber, and a conical exhaust tube. A fuel pump will be used to deliver fuel to the
engine. A nozzle will be installed at the point where the fuel enters the engine to ensure maximum
mixing of air and fuel. The fuel pump will also allow for the throttling of the engine. A spark plug
will be installed to start the combustion process.
The telemetry system will include a microcontroller which will be programmed to read
sensor data from engine temperature sensors and airspeed sensors and send the data wirelessly
to ground based PC where the data will be analyzed using MatLab software. MatLab software will
be programmed to read the data it receives and display the data in a graphical format.
34
13 References
[1] George Mindling, Robert Bolton: US Airforce Tactical Missiles:1949-1969: The Pioneer.
[Internet]. Pp6-31. Available: Lulu.com. [Sept. 11, 2013].
[2] “High Temperature Characteristics of Stainless Steel.” A Designers’ Handbook Series [On-line].
Pp5-11 Available: http://www.nickelinstitute.org/~/Media/Files/
TechnicalLiterature/High_TemperatureCharacteristicsofStainlessSteel_9004_.pdf [Sept. 17, 2013]
[3] B. Simpson. “The Pulsejet Engine FAQ” [Internet] http://aardvark.co.nz/pjet/pjfaq.shtml, January
16, 2003 [Sept. 16, 2013].
[4] R. Ordon. (2006). “Experimental Investigations Into The operational Parameters of a 50
Centimeter Class Pulsejet Engine.” [Internet]. pp27. Available: http://www.johntom.com/JetTurbinePlans/MechEngPapers/MechEngPulseJet%20Experiments.pdf. [Sept. 20, 2013]
[5] “Creep and Stress Rupture Properties.” [Internet]. http://www.ndted.org/EducationResources/CommunityCollege/Materials/Mechanical/Creep.htm. [Sept. 24, 2013].
[6] “Corrosion.” [Internet]. http://www.ndted.org/EducationResources/Community
College/Materials/Physical_Chemical/Corrosion.htm. [Sept. 24, 2013].
[7] M. Zamanzaceh. “Silcolly.” [Internet]. http://www.silcotek.com/Portals/22765/docs
/silcolloy.pdf?&__hssc=&__hstc&hsCtaTracking=fbe62198-ffdd-44d0-8362-b2eac72eb3af|31ceffb08476-4089-a7bb-5b6f88c73c4c. [Sept. 25, 2013].
[8] D. French. “Creep and Creep Failures.” National Board BULLETIN. [On-line]. Available:
http://www.nationalboard.org/Index.aspx?pageID=181. [Sept. 30, 2013]
[9] D.E. Smith. “The Synchronous Injection Ignition Valveless Pulsejet.” Ph.D. thesis, University of
Texas at Arlington. 1987.
[10] B. Simpson. “The Pulse Jet Troubleshooting Guide.” Internet:
http://aardvark.co.nz/pjet/pjet2.htm, [Sep 30, 2013].
[11] F Westberg. (200, April). Inside the Pulsejet Engine. [Online]. Available:
http://www.aardvark.co.nz/pjet/inside_pj.pdf
[12]"Andoya Rocket Range". (2009). Payload Services Telemetry Tutorial (rev.C) [Online]. Available
FTP: ftp://ftp.lpp.polytechnique.fr/robert/keep/Transfert/ICI/Telemetry_Tutorial_RevC.pdf
[13]"Eagle Tree". (2005). User Manual for the Seagull Wireless Dashboard Telemetry and Data
Recorder Systems [Online]. Available FTP:
http://www.eagletreesystems.com/Support/Manuals/Pro,%20Glide,%20Flight%20and%20Boat%20Se
agull%20and%20Data%20Recorder%20Instruction%20Manual.pdf
[14] Gary Katzer. (2010). Understanding RC Batteries [Online].Available FTP: http://www.efliterc.com/Articles/Article.aspx?ArticleID=2106
[15] Anthony William Denne, “Pulse Jet Engines” USA. WO 2005/106234 A2, November 11 2005.
35
[16] Bruce Simpson “Making Reed Valves Last” aardvark.com, May 11, 2002
[17] “What are pulse jet engines and how do they work” Pulsejetengines.com
[18] “Pulse Jet Researsh at NCSU http://www.mae.ncsu.edu/news/article/16442/pulse-jet-researchat-ncsu/ January 2, 2007
[19] Britannica, “Flash Point” [online] 2012
http://www.britannica.com/EBchecked/topic/209573/flash-point [Accessed 11 September 2013]
[20] Hypertextbook, “Energy Density of… “ [online] 2003
http://hypertextbook.com/facts/2003/ArthurGolnik.shtml [Accessed 1 October 2013]
[21] T. Martens, “Airtoi Pulsejet,” [online] 2002 http://www.airtoi.com/pulse.htm [Accessed 15
August 2013]
[22] Wikipedia, “Pulse Jet” http://en.wikipedia.org/wiki/Pulsejet [Accessed 23 August 2013]
[23] Engineering Toolbox, Flash Point Fuels, [online] http://www.engineeringtoolbox.com/flashpoint-fuels-d_937.html [Accessed 11 September 2013]
[24] R. Bradley, J. Hoke, P. Litke, D. Paxson, F. Schauer, “Assessment of the Performance of a
Pulsejet and Comparison with a Pulsed-Detonation Engine” [online] 2005,
www.innssi.com/images/pde03/AIAA-2005-0228.pdf [Accessed 12 September 2013]
[25] D. Perkins, “Static Performance of a Pulsejet Using Ethylene Oxide as a Fuel in Both Liquid and
Gaseous Forms,” [online] 1954, http://www.dtic.mil/dtic/tr/fulltext/u2/058316.pdf, [Accessed 13
September 2013]
[26] Ebay, SR-71 Pulse Jet Engine 7 lbs Thrust PLANS build your own RC Model Airplane [2013],
http://www.ebay.com/itm/SR-71-Pulse-Jet-Engine-7-lbs-Thrust-PLANS-build-your-own-RC-ModelAirplane-/181222672953 [Accessed 12 September 2013]
[27] J. Bourke, "HobbyKing Mercury Alloy 64mm 4700KV EDF Unit," (RCgroups), [online]
2011, http://www.rcgroups.com/forums/showthread.php?t=1533735 (Accessed: 18 August 2013).
[28] Jet Cat USA, Turbines," [online] 2013, http://jetcatusa.com (Accessed: 18 August 2013).
[29] Pulse Jet Engines, Pulse Jet Plans," [online] 2013,
http://www.pulsejetengines.com/freepulsejetplans/ (Accessed: 18 August 2013).
[30] J. Bourke, "MEDUSA 36-60-1600V2 8s testing," (RCgroups), [online]
2008, http://www.rcgroups.com/forums/showthread.php?t=911614 (Accessed: 23 August 2013).
[31] J. Bourke, "Change Sun 12 blade 120mm," (RCgroups), [online]
2011, www.rcgroups.com/forums/showthread.php?t=1545957 (Accessed: 23 August 2013).
[32] Pulse Jet Engines, How Pulse Jets Work," [online] 2013,
http://www.pulsejetengines.com/howpulsejetswork (Accessed: 18 August 2013).
[33]
“MetalsMelting
Temperature.”
[Internet]
Available:
http://www.engineeringtoolbox.com/melting-temperature-metals-d_860.html [Sept. 30, 2013]
36
[34] “Coefficients of Linear Thermal Expansion.” [Internet] Available:
http://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html [Sept. 30, 2013]
[35] http://www.hobbyking.com/hobbyking/store/lithium_polymer_battery_configuration.asp
[36] "Spektrum", TM1000 Telemetry Module User Guide, [Online]
http://www.spektrumrc.com/ProdInfo/Files/SPM9548-Manual_EN.pdf
[37]http://www.hobbyking.com/hobbyking/store/__10343__quanum_2_4ghz_telemetry_syste
m_ volt_amp_temp_mah_v3_0.html
[38] Understating the FCC Regulations for Low-Power, Non-Licensed Transmitters, FCC,
Washington D.C., 1993
37
14 Appendix: Personnel Resumes
DAVID W MORRIS
College Address:
Permanent Address:
401 E College St, Apt. 104
Carbondale, IL 62901
dawillmo@siu.edu
(309)202-7954
800 East Eighth Street
Delavan, IL 61734
dawillmo@gmail.com
(309)244-7471
SUMMARY
Dedicated, Fast Learning, Team Player
EDUCATION
Bachelor of Science in Mechanical Engineering, May 2014 GPA 3.5/4.0
Southern Illinois University, Carbondale, Illinois 62901 Fall 2012 – Present
 Senior Design Project: Designed a pulsejet engine with telemetry system and adapted
it for use in an unmanned airplane
 Relevant Course Work: Introduction to Nanotechnology, Internal Combustion and Gas
 Additional Studies: Minors in Mathematics and Air Traffic Control
Associates in Engineering Science, July 2011 GPA 3.4/4.0
Illinois Central College, East Peoria, Illinois 61611 Fall 2009 – Spring 2012
RELEVANT SKILLS
Programming experience with C++, Java, and Matlab
3D Modeling experience with Pro-Engineer
WORK EXPERIENCE
Menards, Pekin Illinois February, 2012 – July, 2012
Plumbing Morning Stock – Stock the shelves and assist guests with purchases
Delavan Finer Foods June, 2008 – December, 2008
Stock and Carry Out – kept shelves stocked and helped customers carry groceries
Delavan School June, 2007 – August, 2007
Summer Maintenance – helped install new equipment, fix problems, and clean rooms.
INTERESTS AND ACTIVITIES
Volunteer Emergency Medical Technician
Delavan Ambulance Service (June 2010 – August 2013)
Flight Student with solo experience
38
Eileen Schweiss
Email: eschweiss@siu.edu
Personal: (636) 208-3882
Permanent Address
University Address
10 Crystal Lake Ct.
609 E Campus Dr apt 403
Festus, MO 63028
Carbondale, IL 62901
__________________________________________________________________________________
Summary of Qualifications




Hardworking senior in mechanical engineering with a 3.9 GPA
Experienced leader and competitor on the cross country and track teams at a NCAA Division 1 level university
Selected by SIU as the 2013 Lincoln Academy Student Laureate
Completed an internship with Ameren Missouri related to managing the design and implementation of a large scale
project
Education
Southern Illinois University, Carbondale, IL 62901
Bachelor of Science - Mechanical Engineering, May 2014
GPA 3.94/4.0 (108 hours completed)
Senior Design Project:

To design and construct a pulse jet engine to power a flying drone
Specialized Coursework:

Computer Aided Drawing and Manufacturing, Hydraulic and Pneumatic Engineering
Experience
Intern, Callaway Nuclear Energy Center, Ameren MO


Assisted as necessary in tasks related to managing a large scale project
Coordinated with team members and vendors to achieve desired design
Student-Athlete



May 2013-August 2013
August 2010-Present
Competed as a track and cross country athlete at the Division 1 level for SIU
Captain of the cross country and track team for three years
Peer Mentor for underclassmen athletes
Saluki Volunteer Corps



Victory Dream Center - Served food to those in need
Parish Pumpkin Festival - Assisted elementary school with fund raising activities
State Farm Just Read - Read with students at local elementary schools
Tutor, Southern Illinois University


August 2010-Present
August 2011-Present
Tutor athletes in college algebra and calculus
Assist students in reviewing for quizzes and exams
Head Lifeguard, Crystal City Pool


Worked independently, supervised activity at the pool
Maintained facility, performed manager duties, supervised guards




MathWorks MATLAB
Autodesk Inventor Professional 2014
Microsoft Visual C++ 2008
Microsoft Office (Excel, Word, Power Point, Visio)
June 2008-August 2012
Skills
Honors/Awards



SIU College of Engineering nominee for the Lincoln Laureate
SIU Chancellor’s Scholar, 2010 through 2014
Dean’s List 2010-present (Six Semesters)


Academic Outreach Committee Chair of Engineering Student Council
Member of Tau Beta Pi Illinois Epsilon Chapter
Activities
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