Clarkson University KnightHawks Design-Build-Fly Team AIAA Design-Build-Fly Competition ...

234 Pages·2017·6.76 MB·English

Clarkson University KnightHawks
Design-Build-Fly Team

CLA UNI

K H

AIAA Design-Build-Fly Competition
Design Report

February 22, 2018
Table of Contents
Acronyms, Abbreviations, and Symbols 4
1.0 Executive Summary 5
2.0 Management Summary 6
2.1 Team Organization 6
2.2 Milestone Chart 8
3.0 Conceptual Design 8
3.1 Mission Requirements 8
3.2 Design Requirements 11
3.3 Configuration Selection 15
3.4 Configuration Refinement 18
3.5 Final Conceptual Design 20
4.0 Preliminary Design 20
4.1 Design Methodology 20
4.2 Mission Model 21
4.3 Preliminary Sizing 21
4.4 Aerodynamics 23
4.5 Stability and Control 24
4.6 Performance Estimates 26
5.0 Detail Design 27
5.1 Dimensional Parameters Table 27
5.2 Material Characteristics and Capabilities 28
5.3 Structural Design Selected 29
5.4 Sub-System Design and Integration 30
5.5 Weight and Mass Balance 37
5.6 Flight and Mission Performance 38
5.7 Drawing Package 39
42
6.0 Manufacturing Plan 44
6.1 Manufacturing Methods Considered 44
6.2 Manufacturing Methods Selected 44
6.3 Manufacturing Milestone 45
7.0 Testing Plan 45
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7.1 Test Objectives 46
7.2 Subsystem Testing 47
7.3 Flight Test Schedule and Flight Plan 48
7.4 Flight Checklists 49
8.0 Performance Results 50
8.1 Demonstrated Performance of Key Subsystems 50
8.2 Demonstrated Flight Performance of Completed Aircraft 53
Bibliography 55

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Acronyms, Abbreviations, and Symbols

Description Acronym
Design Build Fly DBF
American Institute of Aeronautics and Astronautics AIAA
Unmanned Aerial Vehicle UAV
Computer Aided Design CAD
Figures of Merit FoM
Max Empty Weight EWmax
Stability Augmentation System SAS
Length L
Wingspan b
Coefficient of Lift 𝐶
Coefficient of Drag " 𝐶
#
Rated Aircraft Cost RAC
Zero Angle Coefficient of Lift C
Lo
Coefficient of Moment C
m
Electronic Speed Controller ESC
Vertical Tail Volume Ratio 𝑉
%
Line Replaceable Unit LRU
Nickel-Metal Hydride NiMH
Acrylonitrile Butadiene Styrene ABS
Remote Control RC
Center of Gravity CG
Mission 1 M1
Mission 2 M2
Mission 3 M3
RPM per Volt KV
4
1.0 Executive Summary
The objective of the 2017-2018 American Institute of Aeronautics and Astronautics (AIAA)
Design/Build/Fly (DBF) competition this year was to design and manufacture a dual purpose regional “jet”
aircraft[1]. The aircraft must be capable of carrying both passengers (bouncy balls) and payload
(weighted blocks) on three different flight missions that test the range, speed, and capacity of the aircraft
in various configurations. The aircraft will also be evaluated on its performance in one ground mission
where line replaceable units (LRUs) must be removed and replaced in a timely manner. The flights of the
aircraft are to take place in Wichita, Kansas and will require the aircraft to demonstrate its payload
carrying ability across three flights of differing duration.
For the first mission (M1), the aircraft must take off in 150 ft with no payload completing three laps in
under five minutes. Mission 2 (M2), will consist of three laps under five minutes with the maximum
number of passengers it is capable of carrying, which is declared during technical inspection. The
passengers, represented by bouncy balls, will be sized by choosing randomly from a uniform distribution
of five sizes. The passengers will vary in diameter from 27mm to 49mm and in weight from 0.4ozs to
2.39ozs. Each passenger must have its own seat with an individual restraint system. For the third
mission (M3), the aircraft will fly as many laps as possible carrying at least half of the passengers carried
in M2 with a team determined payload in under ten minutes. The ground mission consists of two stages
where tools must be stored inside the aircraft (Stage 1) and outside the aircraft in a designated area
(Stage 2). In each stage, certain aircraft components are eligible to be removed and the selected part is
chosen based on the roll of a die.
After analyzing overall scoring, it was concluded that minimizing the rated aircraft cost (RAC) through
weight and wingspan was the highest priority. This takes precedence over the flight mission performance,
which will not significantly impact the final score. Because of its high priority, the goal during the design
phase was to limit RAC while still maintaining an aircraft capable of flying all 3 missions.
The flying wing was considered the most appropriate aircraft for its small wingspan and large internal
volume. It allowed for the use of foam construction, which is lighter, cheaper, and easier to manufacture
than the balsa or composite alternatives. Leading and trailing edge foam spars allowed for greater than
necessary strength in wing bending and torsion, while opening up the interior for a passenger cabin,
payload tray, and electronics bay. The aircraft is controlled via solid foam elevons and flight tests have
shown the control authority in both roll and pitch to be more than satisfactory. Additionally, the plane uses
a receiver with a built in Stability Augmentation System (SAS), which allows for increased stability and
higher flight speeds due to fewer large and inefficient pilot corrections. The plane has a single vertical tail
with no controllable rudder to save weight by elimination of a servo. The passenger area is on the same
level as the payload bay, but to the front left of it, adhering to the requirements in the rule set. The motor
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is mounted ahead of the leading edge on a balsa boom to allow for a more stable center of gravity (CG)
location.
Clarkson University’s aircraft, the Knighthawk (Figure 1), maximizes score by being the lightest and
smallest aircraft possible, as determined by the design team, that is capable of completing all three flight
missions. Knighthawk will fly M2 with a single passenger for three laps in 190 seconds. It will fly Mission 3
carrying one passenger and one ounce of payload for a single lap in approximately 60 seconds.
Knighthawk has a wingspan of nine inches and an empty weight of .5 pounds for an RAC of 4.5

Figure 1 - Knighthawk in Flight Configuration.
2.0 Management Summary
2.1 Team Organization
The 2017-2018 Clarkson University Design Build Fly team consists of thirteen students participating on
an extracurricular basis. Two members of the team are seniors, while the remaining eleven are juniors
and underclassmen. The team is completely student-led but suggestions and guidance was given by
faculty members and DBF alumni at design reviews. The leadership of Clarkson University DBF is divided
into the executive board and the engineering design leads as shown in Figure 2.
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Figure 2 - Management Chart
The executive board consists of the two Co-Presidents, a Secretary, a Treasurer, and an External
Relations & Event Planning Manager. The Co-Presidents serve as advisors and administrative leads by
overseeing the design and build processes, advising team members on both technical and logistical
matters, along with managing deadlines. The Secretary manages the DBF mailing list that notifies
members of upcoming meetings, along with managing and organizing DBF shared files in our online
storage. The Treasurer manages the DBF budget and orders components and materials required to
manufacture the aircraft. The External Relations & Event Planning lead manages industry connections
and sponsorships, as well as organizes the travel plans required to get to the competition in April.
The engineering design leads each manage a particular subsystem in the aircraft - Structures,
Aerodynamics, Systems, Propulsions, and Stability & Control. The design team leads work with members
to manufacture their subsystem, and work with each other to integrate the subsystems into a complete
aircraft. Weekly meetings are held where the engineering design leads update the team on the status of
their subsystems, and proposed changes are pitched by team members working on that system. Ideas
that are met with no objections are worked into prototypes and any conflicting ideas are debated by the
team. All final calls for the design are decided by the Co-Presidents.
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2.2 Milestone Chart
Figure 3 - Master Schedule showing current progress against planned timing
Shown above is the Gantt chart that was created and used to help the team meet its deadlines on time.
The black lines through the highlighted boxes represents the team’s progress and the green knight logos
mark the dates of important milestones that need to be met.
3.0 Conceptual Design
The conceptual design phase consisted of analyzing the ruleset and scoring equations to decide on a set
of design parameters for the competition plane. There were three main configurations considered based
off of the need to minimize wingspan, an aspect that stood out in the scoring.
3.1 Mission Requirements
For the 2017-2018 DBF competition, the rules and requirements set by the AIAA simulate a dual purpose
regional and business aircraft. The three flight missions and single ground mission are designed to test
the vehicle’s ability to transport payload as well as passengers, while having functional line replaceable
units (LRUs) and maintaining a reasonable efficiency. The mission requirements were used in conjunction
with the design requirements to optimize the aircraft for a high score.
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360° Turn

180° Turn
500 ft. 500 ft.

150 ft.
(takeoff
length)
This image cannot currently be displayed.
Starting Line
Ground rolling takeoff and landing NOT TO SCALE

Figure 4 - AIAA Competition Course Layout
3.1.1 Scoring Summary
The total score for the 2018 Competition is given by Equation 1
𝑇𝑜𝑡𝑎𝑙 𝑆𝑐𝑜𝑟𝑒 𝑊𝑟𝑖𝑡𝑡𝑒𝑛 𝑆𝑐𝑜𝑟𝑒 𝑇𝑜𝑡𝑎𝑙 𝑀𝑖𝑠𝑠𝑖𝑜𝑛 𝑆𝑐𝑜𝑟𝑒 (Eq. 1)
𝑅𝑎𝑡𝑒𝑑 𝐴𝑖𝑟𝑐𝑟𝑎𝑓𝑡 𝐶𝑜𝑠𝑡
∗
=
The written score is determined as a grade on the design report. The mission score is the sum of the
scores obtained on the three flight missions. The equation for total mission score is shown below in
Equation 2.
𝑇𝑜𝑡𝑎𝑙 𝑀𝑖𝑠𝑠𝑖𝑜𝑛 𝑆𝑐𝑜𝑟𝑒 𝑀 𝑀 𝑀 (Eq. 2)

= ; + = + >
The rated aircraft cost is a function of the plane’s empty weight (EW) and the wingspan (b). The equation
for RAC is given below by Equation 3.
𝑅𝐴𝐶 𝐸𝑊 𝑏 (Eq. 3)
= ∗
3.1.2 Mission 1: Demonstration Flight
For the first mission, the objective is to complete three laps within the five minute designated flight
window with no payload; landing is not considered to be part of the five minute time window. Time starts
when the aircraft throttle is advanced for the first take-off attempt and stops when the aircraft passes over
the start/finish line in the air. Take-off must occur within the prescribed field length and the aircraft must
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complete a successful landing in order to score points. The scoring is pass/fail and shown below in
Equation 4.
M = 1.0 for successful mission (Eq. 4)
1
3.1.3 Mission 2: Short Haul of Max passengers
The objective of the second mission is for the aircraft to complete three laps within five minutes with the
payload being passengers. The aircraft may carry any number of passengers, but the amount flown with
cannot exceed the maximum number of passengers declared at tech inspection. The passengers must be
carried internally and takeoff must occur within the prescribed field length of 150ft. Time starts when the
aircraft throttle is advanced for the first take off attempt and will stop when the aircraft passes over the
start/finish line in the air at the end of the third lap. The landing is not included in the five minute window;
however, the aircraft must have a successful landing to get a score. Exact scoring is shown in Equation 5
below.
M = 2 (Eq. 5)
2
BC(#EFGGHIJHKG/MONH)
∗(QFRC(#EFGGHIJ HKG/MONH))
Where Max_(#passengers/time) is the highest #passengers/time score of all teams
3.1.4 Mission 3: Long Haul of Passengers and Payload
Mission three simulates a long haul of both passengers and payload. The aircraft must carry passengers
and payload internally. Half of the passengers from Mission 2 must be carried, as well as at least one
payload block, but no more than the maximum number declared at tech inspection. The optimal score
would result from the most laps completed in the ten minute window, while carrying as many passengers
and payload as possible. Timing is the same as for the previous missions and a successful landing is
required. The M3 score is given below by Equation 6.

M = 4 + 2 (Eq. 6)
3
BC(#EFGGHIJHKG∗MSMFTEFUTSFV(SW)∗#TFEG)
∗(QFRC(#EFGGHIJHKG∗MSMFTEFUTSFV(SW)∗#TFEG))
Where Max_(#passengers * total payload (oz) * #laps) is the highest (#passengers * total payload (oz) *
#laps score for all teams
3.1.5 Ground Mission: Field and Depot LRU Replacement:
The ground mission must be successfully completed before attempting Flight Mission 2. This mission
consists of a removal and replacement of two LRUs chosen at random with rolls of a single six sided die.
There are 2 stages to this mission. Both stages must be completed within eight minutes, and after
completing Stage 1, teams will immediately continue onto stage 2. Stage 1 consists of Field LRU
Replacement, this must be completed in three minutes and the Replacement LRU and tools must start
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