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Aero Engineering 315
Lesson 2
History of Aeronautical Designand
Introduction to Aircraft Design
First a little more admin…
Seating chart Pick up any missing materials at the
back
Identify major figures in the development of aeronautics and their contributions
State the reasons for designing a new aircraft
State the steps of the design process
Overview/Outcomes
Aviation History
Montgolfier brothers
Cayley *Lilienthal *
ChanuteLangley *Wright Brothers *
Why Design? Q: Why design a brand new airplane? A: To satisfy a need
Threat, shortcoming, cheaper, change in doctrine, vulnerability
Q: Who identifies the need? A: The user (or the manufacturer)
Via Mission Need Statement (MNS)
Mission RequirementsOperational Requirements Document (ORD)
Defined by the user (ACC, AMC, etc.)
Quantify desired aircraft capabilities What are the measures of merit aircraft is
judged on?
Requirements often conflict - must compromise
Critical requirement may drive design
(speed, range, etc.)
(stealth, affordability, performance, logistics, supercruise, maneuverability, lethality, survivability…)
(A-10 gun)
Design Process
Analogous to the scientific method Six steps:
Define the problem (purpose, performance parameters, MOMs)
Collect data (available tech, existing designs, analysis methods)
Create/synthesize one or more design concepts Select types of analysis to evaluate design(s) Perform analyses Make decisions
If necessary, return to step 1 or 2 and repeat process
Design Cycle
Analysis
Synthesis
DecisionMaking
Test concepts against requirementsModel the systemCollect InformationIdentify problems
Consider AlternativesExplain/JustifyCosts and BenefitsScheduleMay involve politics
Create ideasBrainstormThink of PossibilitiesIntegrate existing & surfacing technology
*Leland M. Nicolai, “Designing a Better Engineer,” Aerospace America, April 1992
PRO
VID
ES A
FR
AM
EWO
RK
TO
SOLV
E IL
L D
EFIN
ED P
RO
BLE
MS
The Design Spiral
Radius of Spiral Suggests Range of Feasible Choices
IncreasingInformation
AnalysisAnalysis SynthesisSynthesis
DecisionsDecisions
Design Phases
Conceptual Design - “ideas”, multiple designs Preliminary Design - “models”, wind tunnel
testing, computer optimization Detailed Design - “prototype”, flight testing,
fly-offs, manufacturing processes defined
DESIGN PROCESS MODEL IS USED ITERATIVELY DURING EACH PHASE
Design Cycle Iterative process Occurs within each phase of design Ideally converges to an optimum solution May result in multiple solutions
Sample Mission: B-1
What was the need? What are the requirements? What are the major design features? How do they help the design meet
the requirements?
B-1 Design Mission
X1
2
3 45
6
7
8
9
10
11
12
13
TOTAL RANGE = 5790 NM
1. TAKEOFF/CLIMB TO BCM/BCA 8. ESCAPE (M 0.85, 500 NM)2. CRUISE CLIMB 9. CLIMB TO BCM/BCA3. REFUEL 10. CRUISE CLIMB4. CRUISE CLIMB 11. DESCENT TO ORBIT5. DESCENT TO 200 FT AGL 12. 30 MIN LOITER6. PENETRATION (M=0.85, 1130 NM) 13. LAND7. WEAPONS DELIVERY (24,000 LBS INTERNAL AND 37,500 LBSEXTERNAL ORDNANCE INCLUDING 8 SRAM, 12 ALCM, AND 8 B-61)
B-2 Redesign
Analysis: Not enough Lateral/Directional control Lt Col Lewelen “Doc” Dougherty suggested sawtooth design
Advanced Tactical Fighter (ATF)1981: USSR introduced MiG-31 (improved MiG-25)1981 (Nov): Air Force developed a requirement for an Advanced Tactical
Fighter1984: USSR introduced MiG-29 (F-16 equivalent)1985 (Sep): Air Force issued formal ATF “request for proposal” to major
defense contractors1986: USSR introduced SU-271986 (31 Oct): Air Force narrows field of ATF competitors to two:
Lockheed and Northrop/McDonnell Douglas1990 (27 Aug): First flight of Northrop/MD YF-23 (test pilot Paul Metz)1990 (29 Sep): First flight of Lockheed YF-22 (test pilot Dave Ferguson)1991 (23 Apr): Air Force selected Lockheed YF-22 design as winner of ATF
competition (originally 750 production F-22s expected but later reduced to 648)
1994 (10 Feb): Air Force reduced number of production F-22s from 648 to 422 as a result of military downsizing
1996 (2 Apr): Russia (former USSR) introduced SU-37 (improved SU-27) 1997 (7 Sep): First flight of F-22A (test pilot Paul Metz)1999 (12 Jan): Russia unveiled the Multi-Functional Fighter (known as “Project
1.42” in the West) and claimed it can outperform the F-222005 (Dec): Expected F-22 Initial Operational Capability (IOC) (current
number of production F-22s is now 339)
Joint Strike Fighter1984: USSR introduced MiG-29 (F-16 equivalent)
1986: USSR introduced SU-27
1993: DoD initiated Joint Advanced Strike Technology (JAST) program to address long term attack aircraft force structure requirements for different branches of U.S. Mil
1995: Air Force/Navy/Marines/UK Navy/UK Air Force developed initial requirements document for Joint Strike Fighter
1996 (Apr): Russia (former USSR) introduced SU-37 (improved SU-27)
1996 (Nov): Lockheed Martin and Boeing awarded contracts to develop concept demonstration aircraft
2000 (Sep): First flight of Boeing X-32 (test pilot Fred Knox)
2000 (Oct): First flight of Lockheed X-35 (test pilot Tom Morgenfeld)
2001 (Oct): Air Force selected Lockheed X-35 design as winner of JSF competition, largest military aviation contract ever at over $200 billion
2006: Projected beginning of JSF (F-35) production
2010: Projected JSF (USMC version) Initial Operational Capability (IOC) (current number of production aircraft is 3002: 1763 USAF, 480 USN, 609 USMC, 60 UK Navy, 90 UK AF)
2011: Projected JSF (USAF version) IOC
2012: Projected JSF (USN and UK versions) IOC
Points to Remember
We design to meet a need Must satisfy certain requirements
Many conflict - must compromise A critical requirement may drive the design
3 phases of design: conceptual, prelim, detail Design process:
3-step design cycle: synthesis, analysis, decision making
Is iterative and cyclical Involves many disciplines Compromise is essential Requires creative and analytical thinking May provide multiple solutions (F-22 vs F-23) Final judge is the user
Next Lesson (T3)… Prior to Class
Read 2.1.1 thru 2.2.2 and 2.4 thru 2.6 In Class
Flow properties Perfect gas law Hydrostatic equation Standard atmosphere Altimetry
Air Refueling
Active Ranger
BattleManagement
TILL/BILL
High Energy Laser
IRST
B747-400F
Pressure Bulkhead
IRSTs
Nose-Mounted
Turret
IRST
Airborne Laser (YAL-1A)