AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
Super Close Air Support (SCAS)
“Freedom Fighter”
AE6343 A – Aircraft Design I
Presented by: Michael J. Duffy
Presented to: Prof. Dimitri Mavris
October 16th, 2007
School of Aerospace Engineering
Georgia Institute of Technology
Honor Code Statement
I certify that I have abided by the honor code of the Georgia Institute of Technology and
followed the collaboration guidelines as specified in the project description for this
assignment.
Signed: Michael Duffy
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
Table of Contents
Super Close Air Support (SCAS) ........................................................................................ i
Table of Contents ................................................................................................................ ii
List of Figures .................................................................................................................... iii
List of Tables ..................................................................................................................... iv
Executive Summary ............................................................................................................ 1
Fixed Wing Design (FWD) Tool Description: ................................................................... 3
Layout and Features ........................................................................................................ 3
Layout ......................................................................................................................... 3
Inputs........................................................................................................................... 4
Outputs ........................................................................................................................ 4
Methodology ................................................................................................................... 4
Mission Profile and Payload ....................................................................................... 5
Guessing an Initial Take-Off Gross Weight from Historical Data ............................. 6
Mission Analysis using Fuel Weight Fractions .......................................................... 7
Empty Weight Calculation ........................................................................................ 11
Allowable Empty Weight from Historical Data ....................................................... 11
Implementation of Design Tool for SCAS “Freedom Fighter”: ....................................... 12
Mission Analysis ........................................................................................................... 12
Constraint Analysis ....................................................................................................... 13
Limiting Constraints ................................................................................................. 13
Remaining Constraints .............................................................................................. 15
SCAS - “Freedom Fighter” Design Features: ................................................................... 15
Survivability.................................................................................................................. 16
Weapons ........................................................................................................................ 16
GPU-5/A 30-mm Gun Pod........................................................................................ 16
GBU-32 JDAM Missiles........................................................................................... 17
Aerodynamics ............................................................................................................... 18
Wing Planform .......................................................................................................... 18
Analysis Questions - Design Excursions .......................................................................... 18
Stand Off Weapon vs. Close Air Support ..................................................................... 18
Sustained Turn Rate Effect on Aircraft Structure ......................................................... 19
Field Length (NATO 8,002 ft vs. RFP required 2,000 ft) ............................................ 19
High Temperature (Afghanistan) Take-off and Landing .............................................. 20
Internal Stores Doubled (5,000 lbs vs. 10,000 lbs) ....................................................... 21
Fuel Consumption Reduction of 15% ........................................................................... 22
Add a Dash Segment to the Mission Analysis .............................................................. 23
Conclusion ........................................................................................................................ 23
Appendix A – SCAS “Freedom Fighter” Mission Summary ........................................... 24
Appendix B – Mattingly “Master Equation” Validation of FWD Tool............................ 25
References ......................................................................................................................... 26
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
List of Figures
Figure 1: A-10 Thunderbolt II 3-view ................................................................................ 2
Figure 2: SCAS “Freedom Fighter” 3-view Sketch Using VSP 1.2 ................................... 2
Figure 3: In the FWD Tool the ‘Mission Analyisis’ Tab is Laid Out in Order of the Seven
Steps to Aircraft Sizing from Roskam ................................................................. 5
Figure 4: Super CAS Mission Profile to be Used for Mission Analysis ............................ 6
Figure 5: Historical Weight Trends for Fighter Aircaft ...................................................... 7
Figure 6: Historical Approach Speed from Roskam ......................................................... 14
Figure 7: Constraint Analysis Diagram for the SCAS “Freedom Fighter” ...................... 15
Figure 8: H-Tail is Choosen for “Freedom Fighter” to Improve Survivablity and
Improved Aerodynamics .................................................................................... 16
Figure 9: GPU-5/A 30-mm Gun Placement Relative to Canopy (Behind Pilot View) .... 17
Figure 10: Four JDAM Missiles are Shown as the Most Limiting Case for Sizing and
Constraints ......................................................................................................... 17
Figure 11: Comparison of Planform for the A-10 and SCAS “Freedom Fighter” Aircraft
............................................................................................................................ 18
Figure 12: Constraint Analysis of the SCAS “Freedom Fighter” for Increased Runway
Length ................................................................................................................ 20
Figure 13: The Impact of Increased Temprature at Sea Level on Take-off and Landing
Constraints ......................................................................................................... 21
Figure 14: Constraint Analysis for the SCAS “Freedom Fighter” with a 15% Fuel Flow
Reduction ........................................................................................................... 23
Figure 15: FWD Tool Matches Validation Points ............................................................ 25
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
List of Tables
Table 1: Comparison Data for A-10 and SCAS Vehicle “Freedom Fighter” ..................... 1
Table 2: Payload/Crew for SCAS Mission ......................................................................... 6
Table 3: Typical Fuel Fractions for Various Aircraft Types .............................................. 8
Table 4: Typical Input Values for the Breguet Range Equation for Different Aircaft
Types .................................................................................................................... 9
Table 5: Wetted Area Constants Based on Surface Roughness from Roskam ................... 9
Table 6: Constants used to find Minimum Drag for Various Aircraft ‘Types’ from
Roskam .............................................................................................................. 10
Table 7: Fuel Fraction Summary for SCAS “Freedom Fighter” ...................................... 11
Table 8: Operational and Empty Weight for the SCAS “Freedom Fighter” .................... 11
Table 9: Empty Weight Trends Based on Take-off Weight for Various ‘Types’ of
Aircraft .............................................................................................................. 12
Table 10: Final Empty Weight for the SCAS “Freedom Fighter” ................................... 12
Table 11: Matching Caluated Empty Weight with HItorically Gound Empty Weight for
the SCAS “Freedom Fighter” ............................................................................ 12
Table 12: Comparison of Baseline Design with an Improved 15% Fuel Flow Design .... 22
Table 13: Baseline Mission Summary for the SCAS “Freedom Fighter” ........................ 24
Table 14: Validation Inputs from GATECH AE6343 ...................................................... 25
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
Executive Summary
This report will detail the conceptual design and sizing of a Close Air Support (CAS)
vehicle to full fill AE 6343 Fall 2007 Project 1, based on 2006-2007 AIAA Graduate
Design Competition RFP [1]. The primary goal of this vehicle is to replace the aging yet
invaluable A-10 Thunderbolt II, with a faster, higher range capable aircraft. In addition
to replacement of the A-10’s, the role of this new air vehicle will be to bridge the gap
between the A-10 (CAS vehicle) and the F-16/F/18 (pure fighter vehicle), hence the name
Super Close Air Support (SCAS).
To facilitate the conceptual design and analysis of this aircraft a spreadsheet Fixed Wing
Design (FWD) tool was created using an energy based approach for aircraft design. This
method, outlined in AE 6343 class, Mattingly [4], and Roskam [6] is the basis of this
report. The reader of this report, armed with the FWD tool, Mattingly, and Roskam,
should be capable of repeating the conceptual design of this SCAS vehicle outlined in
this report or any other fixed wing aircraft.
The initially found design solution SCAS vehicle named “Freedom Fighter” is compared
to the current A-10 Thunderbolt II in Table 1, and accompanying 3-views are shown in
Figure 1, and Figure 2.
TABLE 1: COMPARISON DATA FOR A-10 AND SCAS VEHICLE “FREEDOM FIGHTER”
A-10 Thunder Bolt II SCAS “Freedom Fighter”
TOGW
Thrust
T/W Thrust Loading
Wing Span
Length
Wing Area
W/S Wing Loading
Ceiling
Range
Vmax
51,000 lbs
9,065 lbs x 2
0.28
57’6”
53’4”
547 sq.ft.
93 psf
45,000 ft
695 nm
365 knots
59,488 lbs
18,600 lbs x 2
0.625
69’
58’7”
850 sq.ft.
70 psf
45,000 ft
1,600 nm
550 knots
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
57’6”
53’4”
FIGURE 1: A-10 THUNDERBOLT II 3-VIEW
69’
58’7”
FIGURE 2: SCAS “FREEDOM FIGHTER” 3-VIEW SKETCH USING VSP 1.2*
*Note about SCAS “Freedom Fighter” drawings: All “Freedom Fighter” drawings were
made using NASA’s Vehicle Sketch Pad 1.2. This tool is provided as a free open source
code from NASA to industry and academia.
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
Fixed Wing Design (FWD) Tool Description:
The accompanying spreadsheet FWD tool, in which the basis of the report is written on,
is meant to be a stand alone tool for any initial fixed wing design application. For this
reason all references, tables, and figures used in sizing the SCAS vehicle are located in
the FWD tool.
Layout and Features
Layout
The FWD tool used for this project was created in Microsoft Excel. Key functions are
split into different ‘tabbed’ worksheets and labeled by function. Tabs include:
1) Mission Profile – This tab is just a place holder for inserting the mission profile
for reference. For the SCAS “Freedom Fighter”, the mission profile given by the
RFP is shown in this tab
2) Mission Analysis – Based on user inputs, this tab is where the preliminary sizing
of the aircraft’s take-off weight and empty weight are calculated. Figure 3 gives a
screen shot of the mission analysis tab. After the initial inputs are entered, the
user simply clicks the ‘Final Weight Empty’ button, and an Excel macro will vary
take-off weight until empty weight calculated equals empty weight historical (or
geometrically based).
3) Mission Summary – The mission summary collects all the input and output in one
clear concise table, giving the user the ability to compare all segments of the
mission. The SCAS “Freedom Fighter” baseline mission summary is located in
Appendix A.
4) Constraint Analysis – Aircraft performance requirements are calculated in this tab
using the Mattingly “Master Equation” [4].
Examples of performance
requirements calculated for the SCAS “Freedom Fighter”: max speed, service
ceiling, and take-off distance.
5) Thrust to Weight vs. Wing Loading – A summary graph shows the constraint
analysis in the form of T/W (thrust loading) and W/S (wing loading) comparison.
The user can then choose the lowest weight ‘feasible design’ and apply the wing
loading and thrust loading to size the wing, and engine.
6) Drag Polar – The aerodynamic parameters of the wing are entered in the drag
polar tab. The user can input a historically based drag polar here for conceptual
design, and then for preliminary design resize with more sophisticated drag polar
based on CFD or wind tunnel testing. This tab also contains historical regression
data from Roskam [6] to aid in finding an initial drag polar for several classes of
aircraft.
7) Fuel Fractions – Fuel fractions for various ‘types’ of aircraft are listed here from
Roskam’s text.
8) Weight Empty Data – Historical data used for initial TOGW and WE for a variety
of aircraft ‘types’ can be found in this tab.
9) Code Validation – This tab has validation points for the Mattingly “Master
Equation” given in AE 6343 “Fixed Wing Design” course.
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
Inputs
All FWD tool inputs are labeled with references on where the current example SCAS
variables can be found. Some of these reference tables and figures are shown in this
report or in the appropriately labeled tabs in the FWD tool.
Outputs
Primary outputs from the FWD tool are shown on the bottom of the ‘mission analysis’
tab. The calculated empty weight is shown for the given mission requirements. The user
pushes the ‘Find Empty Weight’ Button to calculate the empty weight. In addition to
mission analysis, wing and engine sizing are done with constraint analysis found in the
‘constraint analysis’ tab. The user can input performance requirements, and plot thrust
loading vs. wing loading.
Methodology
The FWD tool uses an energy balance approach of kinetic and potential energy to size
aircraft, which is thoroughly described in Mattingly [4], Raymer [5], and Roskam [6].
This report will only review the basics of the method, and the remainder of the report will
detail how the FWD tool was used to design the SCAS “Freedom Fighter” vehicle.
Roskam outlines seven steps to sizing a vehicle. These steps are labeled in the FWD tool
under the ‘mission analysis’ tab shown in figure 3:
1) Determine payload based on mission requirements.
2) Guess initial take-off weight from historical data trends.
3) Use fuel fractions to estimate weight of fuel burned during the mission.
4) Calculate operational weight empty.
5) Calculate weight empty.
6) Use historical trends to determine the weight empty for the initial take-off gross
weight guess, figure 5 [6]. Note: That this step can be replaced by using actual
weight estimates based on the geometry or individual weight trends for
components. This will tend to give a more representative answer.
7) Change initial take-off weight guess and repeat steps 3 thru 6 until the weight
empty calculated matches the weight empty from historical data
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
Mission Analysis
Step 1
Payload Calculations, W PL
Ammunition Weight (1.62 lbs x 2000 rounds)
Internal Stores Max
External Stores Max
W PL
Total
Crew Weight
Crew (1x250lbs)
Total
3,240
5,000
12,000
12,000
lbs
lbs
lbs
lbs
250 lbs
250 lbs
W CREW
Step 2
Weight Take Off Guess Based on Historical Data, W TO_GUESS
Aircraft Type
W_PL
W_TO
V_MAX
Range
(lbs)
(lbs)
(kts)
(nm)
F.R. A10A
15,000
50,000
450
540
Grumman A6
17,000
60,400
689
1,700
Tornado F.Mk2
16,000
58,400
600
750
Average:
16,000
56,267
580
997
W TO_GUESS
59,488 lbs
Step 3
Mission Fuel Weight Fractions, W F
Profile
Warm-up Taxi
Step 4
Max Perforamnce Take-Off @ SL
Weight Fractions:
W 1/W TO
0.990
W 2/W 1
0.990
Max Power Climb to Opt. Alt.
W 3/W 2
0.960
Cruise out 800 nm @ Optimum Speed/Alt
W 4/W 3
0.930
Loiter for 20 min. @ 5,000ft
W 5/W 4
0.986
20 min. Combat @ Corner Speed/SL
W 6/W 5
0.974
Max Power Climb to Opt. Alt.
W 7/W 6
0.960
Cruise Back 800 nm @ Optimum Speed/Alt
W 8/W 7
0.927
Descend to SL @ Idle Thrust Setting
W 9/W 8
1.000
20 min Loiter @ Endurance Speel/SL
W 10/W 9
0.986
Landing with 30 min Reserve Fuel @ SL
W 11/W 10
0.979
Total Fuel Fraction
Total Weight of Fuel Required
WL/WTO
16,516 lbs
0.722
WF
Initial Operation Weight Empty, W OE
W OE = W TO_GUESS - W F - W PL
W OE
Step 5
30,973 lbs
Initial Weight Empty, W E
W E = W OE - W TFO - W CREW
W TFO
WE
-
lbs
30,723 lbs
Step 6
Allowable Weight Empty From Historical Data, W E_HIST
A
Regression Const. (Fighter + Ext Load)
0.5091
B
Regression Const. (Fighter + Ext Load)
0.9505
Weight Empty from Historical Data W E_HIST
30,723 lbs
Step 7
Adjust Take Off Weight Guess Until W E = WE_HIST
First Iteration
WE
30,723 lbs
W E_HIST
Error
30,723 lbs
0 lbs
FIGURE 3: IN THE FWD TOOL THE ‘MISSION ANALYISIS’ TAB IS LAID OUT IN ORDER OF
THE SEVEN STEPS TO AIRCRAFT SIZING FROM ROSKAM
Mission Profile and Payload
First a mission profile is defined by some set of requirements; in this case it is a close air
support vehicle to replace aging A-10 anti-tank aircraft. Figure 4 from the RFP [1] shows
the mission profile used in this design study.
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
FIGURE 4: SUPER CAS MISSION PROFILE TO BE USED FOR MISSION ANALYSIS
Payload is usually accompanied with a mission profile such as the one given for the
SCAS mission. Payloads for this mission range from internal cargo of 5,000 lbs to
external cargo of 12,000 lbs; therefore, the most limiting design constraint of 12,000 lbs
is used. In addition to the weight of the payload the drag of the aircraft will also go up
due to the additional excrescences. Table 2 outlines the internal cargo, external cargo and
crew weight.
TABLE 2: PAYLOAD/CREW FOR SCAS MISSION
Payload Calculations, WPL
Ammunition Weight (1.62 lbs x 2000 rounds)
3,240
Internal Stores Max
5,000
External Stores Max
12,000
W PL
Total
12,000
Crew Weight
Crew (1x250lbs)
Total
W CREW
lbs
lbs
lbs
lbs
250 lbs
250 lbs
Guessing an Initial Take-Off Gross Weight from Historical Data
To get an order of magnitude for what a new aircraft should look like and weigh, it is
common to begin with historical data. First, a class of aircraft with similar mission
requirements and/or capabilities is selected. For purpose of this study, the A-10, F-16,
and F-18 all fall into the ‘Fighter’ class of aircraft. Figure 5 from Roskam [6] shows an
historical regression of take off gross weight (TOGW) to weight empty (WE). This plot
will later be used to correct the initial TOGW guess with the WE that is acquired from
the mission analysis portion of the FWD tool.
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
FIGURE 5: HISTORICAL WEIGHT TRENDS FOR FIGHTER AIRCAFT [6]
For the purpose of sizing an initial take-off gross weight for the SCAS vehicle the A-10
with a payload of 15,000 lbs and a take-off gross weight of 50,000 lbs, the Grumman A6
(PL = 17,000lbs, TOGW = 60,400lbs) and the Tornado F.Mk2 (PL = 16,000 lbs, TOGW
= 58,400lbs) are averaged to get and initial guess for the SCAS TOGW of 56,267 lbs.
This weight will be used as a starting point for the mission analysis outlined in the next
section.
Mission Analysis using Fuel Weight Fractions
The end goal for running mission analysis is simply to find the total fuel burned during
the mission. To accomplish this, the mission is broken into small manageable segments,
in which fuel fractions can be calculated or looked up. For short relatively simple
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
segments such as taxi, take-off, climb, descent and landing, table 3, found in Roskam [6],
can be used for a variety of aircraft.
The SCAS “Freedom Fighter” is classified in the fighter airplane type in table 3. The
fuel fractions used for “Freedom Fighter” are highlighted by the red box. These fuel
fractions are multiplied together and then multiplied by the TOGW to determine the total
fuel burned for the given mission.
TABLE 3: TYPICAL FUEL FRACTIONS FOR VARIOUS AIRCRAFT TYPES [6]
For cruise and loiter missions, the range and time need to be factored into the fuel
fraction. To determine the fuel burned during a cruise and loiter, the Breguet Range
equation is rearranged into the form shown in equation 1 and 2 from Roskam [6]. Values
for cj and cp can be found from table 4. Table 4 can also be used to find typical values of
L/D; however, if a drag polar is assumed the user can calculate L/D based on
instantaneous mission weight.
Equation (1)
Equation (2)
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
TABLE 4: TYPICAL INPUT VALUES FOR THE BREGUET RANGE EQUATION FOR DIFFERENT
AIRCAFT TYPES [6]
The drag polar is found using equations 3 thru 6, table 5, and 6 from Roskam [6], page
118 -120.
,
Equation (3)
Equation (4)
,
,
Equation (5)
,
Equation (6)
TABLE 5: WETTED AREA CONSTANTS BASED ON SURFACE ROUGHNESS FROM ROSKAM [6]
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
TABLE 6: CONSTANTS USED TO FIND MINIMUM DRAG FOR VARIOUS AIRCRAFT ‘TYPES’
FROM ROSKAM [6]
Marked in red on tables 3 thru 6 are the values used for the SCAS “Freedom Fighter”;
except, L/D was calculated at the beginning of each cruise and loiter segment, based on
the instantaneous weight. In addition, the SCAS pays a drag penalty in cruise for the four
external stores; this is accounted for in the min drag calculation. Roskam estimates 3.2
sq.ft. of drag for a typical external load, page 156. This increase in drag is captured in the
L/D found in equations 1, and 2.
Final fuel fractions for all mission segments are multiplied by TOGW to get the total fuel
burned during the mission. Table 7 depicts the final fuel burn for the SCAS “Freedom
Fighter”. Total Fuel burned during the mission is 16,516 lbs, including the 30 min
reserve fuel.
10
Aircraft Type
W_PL
W_TO
V_MAX
Range
Payload Calculations, W
PL
(lbs)
(lbs)
(kts)
(nm)
Ammunition
Weight (1.62 lbs15,000
x 2000 rounds)
3,240
F.R. A10A
50,000
450 lbs 540
Internal
Stores Max
5,000
Grumman
A6
17,000
60,400
689 lbs 1,700
AE6343-Aircraft Design
I –Stores
Conceptual
Design
Oct
External
Max
12,000
lbs 750
Tornado
F.Mk2
16,000 - SCAS
58,400 Michael
600 Duffy,
Total
12,000
Average:
16,000 W PL 56,267
580 lbs 997
W TO_GUESS
59,488 lbs
Crew FRACTION
Weight
TABLE 7: FUEL
SUMMARY FOR SCAS “FREEDOM FIGHTER”
Crew
(1x250lbs)
250 lbs
Mission
Fuel Weight Fractions, W F
Step 3
W CREW
Total
250 lbs
Step 1
Step 2
Step 3
Profile
Weight Fractions:
Weight
Take
W 1W
/WTO_GUESS
Warm-up
TaxiOff Guess Based on Historical Data,
0.990
TO
Aircraft
Type
W_PL
W_TO
V_MAX
Range
W
Max Perforamnce Take-Off @ SL
0.990
2/W 1
(lbs)
(lbs)
(kts)
(nm)
W
Max Power Climb to Opt. Alt.
0.960
3/W 2
F.R. A10A
15,000
50,000
450
540
W 4/W 3
Cruise
out
800
nm
@
Optimum
Speed/Alt
0.930
Grumman A6
17,000
60,400
689
1,700
Loiter
for 20 F.Mk2
min. @ 5,000ft 16,000
0.986
Tornado
58,400 W 5/W 4 600
750
Average:
16,000
56,267 W 6/W 5 580
997
20 min. Combat @ Corner Speed/SL
0.974
W TO_GUESS W 7/W59,488
lbs
Max Power Climb to Opt. Alt.
0.960
6
Cruise Back 800 nm @ Optimum Speed/Alt
Mission
WF
DescendFuel
to SLWeight
@ Idle Fractions,
Thrust Setting
20 min Loiter @ Endurance Speel/SL
Profile
Landing with 30 min Reserve Fuel @ SL
Warm-up Taxi
Step 4
16th, 2007
Max
TotalPerforamnce
Fuel FractionTake-Off @ SL
Max
Power
Climb
to Opt.
Alt.
WF
Total Weight
of Fuel
Required
Cruise out 800 nm @ Optimum Speed/Alt
Initialfor
Operation
Weight
Loiter
20 min. @
5,000ftEmpty, W OE
Empty Weight Calculation
20
Combat
@ -Corner
Wmin.
W F - WSpeed/SL
OE = W
TO_GUESS
PL
W 8/W 7
0.927
W 9/W 8
1.000
W 10/W 9
0.986
Weight Fractions:
W 11/W 10
0.979
W 1/W TO
0.990
W 2/W 1
WL/WTO
W 3/W
2
16,516
lbs
W 4/W 3
0.990
0.722
0.960
W 5/W 4
0.986
W 6/W 5
0.974
0.930
W 7weight.
/W 6
Max Power
Climb to Opt.
Alt.
0.9608 shows the
Step 4 and 5 are simply
calculating
operational
and empty
Table
W OE
30,973 lbs
W
/W
Cruise
Back
800
nm
@
Optimum
Speed/Alt
0.927
8
7
equations used and the values for the SCAS “Freedom Fighter”. The difference
between
W 9/W 8
Descend to SL @ Idle Thrust Setting
Initial
Weight Empty,
operational and
weight
are theW Emission specific equipment that1.000
goes into the
Step 5empty
W 10/W 9
20 min Loiter @ Endurance Speel/SL
0.986
aircraft. For the SCAS
W E“Freedom
= W OE - W TFOFighter”
- W CREW all mission equipment is assumed to be in the
W 11/W 10
Landing
with 30 min Reserve
Fuel @ SL
0.979
weight empty. Final weight empty for the “Freedom
Fighter” is- calculated
to be 30,723
W TFO
lbs
lbs
Total Fuel Fraction
WL/WTO
WE
30,723 lbs 0.722
WF
Total Weight of Fuel Required
16,516 lbs
TABLE 8:Step
OPERATIONAL
AND
EMPTY
FOR THE
Allowable
Weight
EmptyWEIGHT
From Historical
Data, SCAS
W E_HIST“FREEDOM FIGHTER”
6
Step 4
Initial
Operation
Weight
Empty,
W OE + Ext Load)
A
Regression
Const.
(Fighter
B
Regression
Const.
(Fighter
+ Ext Load)
W OE = W TO_GUESS - W F - W PL
Weight Empty from Historical Data W E_HIST
W OE
0.5091
0.9505
30,723 lbs
30,973 lbs
Step 7
Step 5
Adjust Take Off Weight Guess Until W E = WE_HIST
Initial
Weight Empty, W E
First Iteration
W
WE = W - W
-W
30,723 lbs
E
OE
TFO
CREW
W E_HIST
Error
W TFO
WE
30,723
0
30,723
lbs
lbs
lbs
lbs
Allowable Weight Empty From Historical Data, W E_HIST
Const. (Fighter + Data
Ext Load)
0.5091
Allowable EmptyAWeightRegression
from Historical
B
Regression Const. (Fighter + Ext Load)
0.9505
The allowable empty Weight
weight
based
historical
can be found
onelbsof
W E_HIST
Empty
fromon
Historical
Data data
30,723
Step 6
three ways:
1) Table 9 from Roskam [6] shows the trends and constants used to calculate the
Adjust
Weightaircraft
Guess Until
W E =same
WE_HIST‘type’. The red box in table 9
Step
7
weight
empty
basedTake
on Off
various
of the
First Iteration
shows the values
used for the SCAS “Freedom Fighter”
WE
30,723 lbs
2) For a more representative
weight that captures the individual weight break down
W E_HIST
30,723 lbs
for all major aircraft
components, the user can choose to gather
Error
0 lbs historical TOGW
trends by component. Many of these trend equations can be found in Raymer [5],
or Roskam [6]
3) For the most accurate method, the user can have a preliminary designer mock up
each component, and have a weights engineer give estimates based on wetted
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
area, structural thickness, and volumes, for each component. This however, is
time consuming and manpower intensive; therefore, is usually saved for the
preliminary design phase, as opposed to the conceptual design phase.
TABLE 9: EMPTY WEIGHT TRENDS BASED ON TAKE-OFF WEIGHT FOR VARIOUS ‘TYPES’
OF AIRCRAFT [6]
The initial take off gross weight guess is adjusted for several iterations before the empty
weight shown in table 10 and 11 were found. Based on a TOGW of 59,488 lbs the
“Freedom Fighter” weight empty is 30,723 lbs
TABLE 10: FINAL EMPTY WEIGHT FOR THE SCAS “FREEDOM FIGHTER”
Step 6
Allowable Weight Empty From Historical Data, W E_HIST
A
Regression Const. (Fighter + Ext Load)
0.5091
B
Regression Const. (Fighter + Ext Load)
0.9505
Weight Empty from Historical Data W E_HIST
30,723 lbs
TABLE 11: MATCHING CALUATED EMPTY WEIGHT WITH HITORICALLY FOUND EMPTY
WEIGHT FOR THE SCAS “FREEDOM FIGHTER”
Step 7
Adjust Take Off Weight Guess Until W E = WE_HIST
First Iteration
WE
30,723 lbs
W E_HIST
Error
30,723 lbs
0 lbs
Implementation of Design Tool for SCAS “Freedom
Fighter”:
Mission Analysis
Based in the mission analysis done in the previous section the take-off weight of 59,488
lbs was found to meet the mission profile requirements. Now the user must size the
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
engine and wing to meet RFP’s point performance specifications. The next section will
review how the constraint analysis was done for the SCAS “Freedom Fighter”.
Constraint Analysis
The ‘constraint analysis’ tab provides the user the ability to apply the Mattingly “Master
Equation” [7] for thrust loading and wing loading to size the engine and wing. This ties
together the mission analysis with the constraint analysis to give a final design. The user
can specify the design constraints, and find the optimum (lowest weight) aircraft that
meets all the specified requirements.
Equation (7)
The final design point for the SCAS “Freedom Fighter” is found at a minimum thrust
loading of T/W =0.625 shown in figure 7. The constrains that drive the final design are
take-off distance, landing distance, sustained turn, and climb rate. The remaining
constraints have no impact on the design, but are still plotted to show compliance with
the RFP requirements
The SCAS “Freedom Fighter” T/W of 0.625 corresponds to a wing loading of 70 psf.
Given the TOGW was found to be 59,488 lbs, the final wing area (850 sq.ft.) and thrust
required (18,500 lbs x 2) can be computed.
Limiting Constraints
1) 2,000 ft Take-off – Take-off distance is based finding a representative CLmax and
applying it to the take-off distance equation found in Raymer [5]. CLmax for a
fighter is found in Roskam [6] to be around 1.9. Rolling friction and flaps down
drag are found in Roskam page 145.
2) 2,000 ft Landing Distance – Take-off distance is determined using the method
found in Roskam, page 187. The approach speed is found from historical data
from Roskam, figure 6. This is then applied to find the desired CLmax to fit the
2,000 ft field length for the SCAS. Since a CLmax used for take-off was 1.9, the
same CLmax was used for landing.
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
FIGURE 6: HISTORICAL APPROACH SPEED FROM ROSKAM [6]
3) 10,000 ft/min climb rate – Rate of climb is found using the Mattingly “Master
Equation”, where the vertical velocity is defined as 10,000 ft/min. Be careful to
correct the units to ft/s to match the units used in the “Master Equation”.
4) 12°/s Turn Rate – The load factor, n is determined using Raymer [5], page 106
where the user can input a turn rate and a free stream velocity. This equation is
programmed into the FWD tool; hence, the user need only input turn rate and free
stream velocity. The velocity is assumed to be the cruise speed of 459 knots,
which makes the n value 5.14 g’s for the SCAS “Freedom Fighter”. The load
factor is then plugged into the Mattingly “Master Equations” to determine the
T/W vs. W/S.
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AE6343-Aircraft Design I – Conceptual Design - SCAS
2,000 ft Landing
Michael Duffy, Oct 16th, 2007
2,000 ft TakeTake-off
1.4
1.2
Feasible
Design
Space
12°
12°/s Sustained Turn @ 459 kts
Final
Design
Point
Combat Corner Speed of 275 kts
T/W – Thrust Loading
1.0
0.8
10,000 ft Rate of Climb
0.6
Service Ceiling 45K ft
0.4
Level Cruise, 459 knots
Max Speed, 550 knots
0.2
Stall Speed of 100 knots (SL, MTGW)
0.0
0
25
50
75
100
125
150
175
200
W/S – Wing Loading
FIGURE 7: CONSTRAINT ANALYSIS DIAGRAM FOR THE SCAS “FREEDOM FIGHTER”
Remaining Constraints
1) Combat Corner Speed at 275 knots – Similar to turn rate, corner speed is defined
by a load factor, n. For the SCAS “Freedom Fighter” this value was found using
Raymer [5], page 106 and setting the free stream velocity to 275 knots
2) Service Ceiling of 45,000 ft – Raymer defines that the service ceiling be the
altitude at which the minimum rate of climb is 100 ft/min to allow for maneuver.
3) Max Speed, 550 knots – Max speed is defined in the RFP as 550 knots, and is
assumed to be capable at the cruise altitude of 42,000 ft. The cruise altitude is
defined by the example given in Roskam, page 118 for a ‘fighter’ aircraft.
Because of the high mach number of 0.986, a component of minimum drag
(CD_0 = 0.0025, found in Roskam, page 166) is added for compressibility. The
wings are also swept aft according to Raymer [5] to reduce transonic drag (figure
11).
4) Min Stall Speed of 100 knots – Stall speed is defined in the RFP, and is required at
sea level, max take-off weight.
5) Level Cruise Speed – Cruise speed of 459 knots is defined in Roskam [6], page
62, for a fighter. The altitude of 42,000 ft is also found in Roskam, page 62.
SCAS - “Freedom Fighter” Design Features:
It is up to the user of the FWD tool to do research on unique design constraints and
features, such as engine placement, wing shape, gear configuration, etc. The tool only
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
provides quantitative values for major design parameters. For this aspect of design
Roskam [6] and Raymer [5] both have good initial layout and qualitative design
discussions. For the SCAS vehicle several key design considerations come to mind.
Survivability
Raymer talks specifically about the A-10’s H-tail design as being a feature for
survivability. More specifically the H-tail tail partially shields the engines from ground
enemy fire, as does the mounting of the engines above the fuselage, and not under the
wings. Figure 8 shows a quick design study using Vehicle Sketch Pad to model what the
“Freedom Fighter” might look like with a conventional tail as opposed to an H-tail. For
the “Freedom Fighter’s” design mission it is important to maintain high survivability, in
addition the H-Tail provides a favorable end plate effect for the horizontal stabilizer;
therefore, the H-tail is chosen over the conventional tail.
More Horizontal Tail Required
Because of No End Plate Effect
H-Tail Partially Shields Engines from
Enemy Ground Fire
FIGURE 8: H-TAIL IS CHOOSEN FOR “FREEDOM FIGHTER” TO IMPROVE SURVIVABLITY
AND IMPROVED AERODYNAMICS
Weapons
GPU-5/A 30-mm Gun Pod
The RFP states that a GPU-5/A 30mm gun pod be fitted to the aircraft at all times. This
presents a unique design layout problem, as forward firing guns can cause great
distraction when smoke invades the pilots view (Raymer [5]). This can be over come by
placing the muzzle behind the pilot, also making for a more favorable CG. Figure 9
shows cannon placement on the SCAS – “Freedom Fighter”.
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
Forward Firing Cannon Located Aft of Pilot
To Reduce Smoke Invasion on the Canopy
FIGURE 9: GPU-5/A 30-MM GUN PLACEMENT RELATIVE TO CANOPY (BEHIND PILOT VIEW)
GBU-32 JDAM Missiles
The most limiting case in sizing the SCAS is the external stores of 12,000 lbs, Figure 10
shows their layout.
FIGURE 10: FOUR JDAM MISSILES ARE SHOWN AS THE MOST LIMITING CASE FOR SIZING
AND CONSTRAINTS
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
Aerodynamics
Wing Planform
A swept wing was chosen for the “Freedom Fighter” to alleviate transonic drag rise
(Figure 11). This is not a problem for the A-10; however, the “Freedom Fighter” will be
flying at much higher speeds where drag divergence can severally penalize cruise.
Compared to the A-10 which was designed to have all ‘flat wrapped’ surfaces (meaning
no compound surfaces) the wing for the SCAS aircraft will be more expensive and harder
to manufacture; however, with today’s use of composites, this is becoming less of an
issue.
Top View
A-10 Thunderbolt II Wing Platform
SCAS Peace Keeper Wing Platform
Swept Aft to reduce
transonic drag
FIGURE 11: COMPARISON OF PLANFORM FOR THE A-10 AND SCAS “FREEDOM FIGHTER”
AIRCRAFT
Analysis Questions - Design Excursions
Additional design excursions are provided to give the user examples of how changing the
design constraints affect the sizing and performance of the SCAS “Freedom Fighter”.
Stand Off Weapon vs. Close Air Support
Design ‘excursion 1’ is found under the “mission excursion 1” tab in the FWD tool. The
purpose of the first excursion is to see if the SCAS “Freedom Fighter” can perform a
stand off mission as apposed to a close air support. The mission deviates from the
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
baseline mission by replacing the 20 min loiter and combat segments with a one hour
loiter and release of half the payload (bombs, strafe),
The mission analysis is re-run and shows that the excursion 1 mission requires 16,279 lbs
of fuel, this is less then the baseline design fuel capacity of 16,516; therefore, a surplus of
237 lbs fuel remains. This extra fuel could be used to extend the range, or loiter time.
Sustained Turn Rate Effect on Aircraft Structure
A sustained turn requires the aircraft structure to operate at higher loading factor then
one. This means that a structure that is sized to just handle the weight of the aircraft at
level flight, where n =1, would break if exposed to a sustained turn which requires the
structure to hold 5-7 times the level flight loads. From a structural design prospective, a
sustained turn exudes the largest loads that the aircraft will see in its flight envelope;
therefore, is the critical design constraint.
Field Length (NATO 8,002 ft vs. RFP required 2,000 ft)
Increasing field length to any length over 2000 ft has no impact on the chosen T/W and
W/S of the current final design point. Figure 12 shows that when the take-off and
landing constraints are completely removed the minimum of thrust loading is still found
at 70 psf. This means that only decreasing the field length to less than 2000 ft will
impact the current design.
Field length is not the only constraint a designer must consider when sizing for take-off
and landing. Austere environments like Afghanistan, can affect take-off and landing
ambient conditions like in the next section: the increased ambient temperatures can cause
the landing and take-off performance to degrade, requiring a longer field for take-off. In
addition, rough field can force the designer to size the gear stroke to allow for a minimum
clearance between ground and obstacles. An example would be a minimum clearance
required between the underside of the fuselage with the gear fully compressed and the
ground (or rock, bump).
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
1.4
Feasible Design Space w/o
TakeTake-off and Landing
Constraints
1.2
12°
12°/s Sustained Turn @ 459 kts
T/W – Thrust Loading
1.0
Final Design Point
Combat Corner Speed of 275 kts
0.8
10,000 ft Rate of Climb
0.6
Service Ceiling 45K ft
0.4
Level Cruise, 459 knots
Max Speed, 550 knots
0.2
Stall Speed of 100 knots (SL, MTGW)
0.0
0
25
50
75
100
125
150
175
200
W/S – Wing Loading
FIGURE 12: CONSTRAINT ANALYSIS OF THE SCAS “FREEDOM FIGHTER” FOR INCREASED
RUNWAY LENGTH
High Temperature (Afghanistan) Take-off and Landing
The ambient condition plays a critical role in the take-off/landing constraint for the SCAS
“Freedom Fighter”. Increasing the temperature at sea level from 59° to 110° to simulate
an Afghanistan take-off mission caused the current baseline SCAS “Freedom Fighter”
design to miss the 2,000 ft requirement. The run-way length would have to be 2,165 feet
for the current SCAS “Freedom Fighter” design to take off at SL, 110° F. Figure 13
shows both take-off and landing for standard day 59° and the 110° “Afghanistan day”.
The current design point lies outside of the new feasible design space with the adjusted
requirement.
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AE6343-Aircraft Design I – Conceptual Design - SCAS
2,000 ft Landing
Michael Duffy, Oct 16th, 2007
2,000 ft TakeTake-off
,5
SL
0.8
10,000 ft Rate of Climb
0.6
0.4
SL, 59°
T/W – Thrust Loading
1.0
12°
12°/s Sustained Turn @ 459 kts
9°
SL
, 11
1.2
0°
SL, 110°
1.4
0.2
The hot day conditions forces the taketakeoff/landing lines above the current design point
0.0
0
25
50
75
100
125
150
175
200
W/S – Wing Loading
FIGURE 13: THE IMPACT OF INCREASED TEMPRATURE AT SEA LEVEL ON TAKE-OFF AND
LANDING CONSTRAINTS
Internal Stores Doubled (5,000 lbs vs. 10,000 lbs)
From a constraint analysis and mission performance perspective, increasing the internal
stores will not impact the current design of the SCAS “Freedom Fighter”. Reason being
is that the external stores is the most limiting case at 12,000 lbs, and increased minimum
drag; however, internal stores can cause a large problem for volume limited
configurations such as a ‘fighter’ type aircraft. Increasing internal stores can have a
significant impact on structures and manufacturing. Increasing internal stores might
interfere with the wing carry through structure. A wing box connects the load path
between wings and fuselage. The wing box design is typically the lightest configuration;
however, if the internal volume is occupied by internal stores, then the wing box might
have to be replaced with less efficient carry through structure like ‘Ring Frames’ or
‘Beam Bending Frames’ as shown in Raymer [5], figure 8.12.
In addition to structural considerations, manufacturing must be considered, as today
many aircraft are assembled using subassemblies. Figure 8.23 in Raymer [5] shows the
subassemblies for the SAAB Draken. Subassemblies can be affected by having large
compartments that span the length of the fuselage, like for internal stores, causing the
sub-assembly size to grow undesirably large.
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AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
Fuel Consumption Reduction of 15%
The 15% reduction in fuel flow significantly reduced the take-off gross weight of the
baseline SCAS “Freedom Fighter” design. Table 12 shows comparison of the baseline
with the improved fuel flow version. A reduction of mission fuel caused a cascade effect,
reducing take-off weight by 12,000 lbs. The constraint analysis shown in figure 14 was
not as significantly affected because the major driving constraints like climb rate, take-off
and landing field length did no move; however, even with no change in thrust and wing
loading, the reduced take-off weight reduces wing area, and required engine size, shown
in table 12.
TABLE 12: COMPARISON OF BASELINE DESIGN WITH AN IMPROVED 15% FUEL FLOW
DESIGN
Baseline SCAS
SCAS “Freedom Fighter”
“Freedom Fighter” w/ 15% Fuel Flow
Reduction
TOGW
Thrust
T/W Thrust Loading
Wing Span
Length
Wing Area
W/S Wing Loading
Ceiling
Range
Vmax
59,488 lbs
18,600 lbs x 2
0.625
69’
58’7”
850 sq.ft.
70 psf
45,000 ft
1,600 nm
550 knots
47,522 lbs
15,000 lbs x 2
0.625
55.2’
47”
678 sq.ft.
70 psf
45,000 ft
1,600 nm
550 knots
22
AE6343-Aircraft Design I – Conceptual Design - SCAS
2,000 ft Landing
Michael Duffy, Oct 16th, 2007
2,000 ft TakeTake-off
1.4
1.2
T/W – Thrust Loading
1.0
Final
Design
Point
0.8
12°
12°/s Sustained Turn @ 459 kts
Combat Corner Speed of 275 kts
0.6
10,000 ft Rate of Climb
Service Ceiling 45K ft
0.4
Level Cruise, 459 knots
Max Speed, 550 knots
0.2
Stall Speed of 100 knots (SL, MTGW)
0.0
0
25
50
75
100
125
150
175
200
W/S – Wing Loading
FIGURE 14: CONSTRAINT ANALYSIS FOR THE SCAS “FREEDOM FIGHTER” WITH A 15% FUEL
FLOW REDUCTION
Add a Dash Segment to the Mission Analysis
Replace the 800 nm cruise with a 200 nm Mach 0.87 dash segment and the remaining
600 nm is a cruise at best range speed. The mission analysis for this profile can be found
in the FWD tool under the ‘mission excursion 2’ tab. The take-off weight resized with
the new segment and is found to increase from 59,488 lbs (baseline design) to 62,414 lbs.
One driver of this increase is the added compressibility drag due to the high Mach
number cruise. This drag penalty can be reduced with a more advanced wing planform.
Sweeping the wing leading edge aft by some amount can reduce the compressibility drag
rise. Figure 11 shown under the SCAS “Freedom Fighter” design features section shows
a comparison of the A-10 planform which flies much slower then the SCAS “Freedom
Fighter”.
Conclusion
The Fixed Wing Design Tool provided with this report has designed an aircraft with
nearly twice the speed, and triple the range to meet the RFP [1] requirements. The SCAS
“Freedom Fighter” design has been completely laid out step by step in this report for any
user of the FWD tool to change and modify inputs to fit his or her design requirements.
23
AE6343-Aircraft Design I – Conceptual Design - SCAS
Appendix A –
Summary
SCAS
Michael Duffy, Oct 16th, 2007
“Freedom
Fighter”
Mission
This appendix shows the last iteration of the SCAS “Freedom Fighter” from the mission
analysis.
TABLE 13: BASELINE MISSION SUMMARY FOR THE SCAS “FREEDOM FIGHTER”
Mission Summary (Baseline Mission)
Seg.
0
1
2
3
4
5
6
7
8
9
10
11
Description
Warm-up Taxi
Max Perforamnce Take-Off @ SL
Max Power Climb to Opt. Alt.
Cruise out 800 nm @ Optimum Speed/Alt
Loiter for 20 min. @ 5,000ft
20 min. Combat @ Corner Speed/SL
Max Power Climb to Opt. Alt.
Cruise Back 800 nm @ Optimum Speed/Alt
Descend to SL @ Idle Thrust Setting
20 min Loiter @ Endurance Speel/SL
Landing with 30 min Reserve Fuel @ SL
Altitude
(ft)
0
0
0
42,000
42,000
5,000
0
42,000
42,000
0
0
0
Temp.
(°F)
59.0
59.0
59.0
-90.6
-90.6
41.2
59.0
-90.6
-90.6
0.0
0.0
0.0
Density Velocity Range
slug/ft^3
knots
nm
2.377E-03
0.0
2.377E-03
0.0
2.377E-03 TBD
5.571E-04 350.0
25
5.571E-04 459.0
800
2.048E-03 226.6
800
2.377E-03 275.0
800
5.571E-04 350.0
825
5.571E-04 459.0
1,600
2.377E-03 459.0
1,600
2.377E-03 187.5
1,600
2.377E-03
0.0
1,600
24
q
psf
0
0
0
167
150
256
167
167
119
0
CL
CD
L/D
0.0000
0.0000
TBD
0.3940
0.4088
1.1794
0.3379
0.3379
0.4400
0.0000
0.0172
0.0172
TBD
0.0282
0.0291
0.1160
0.0253
0.0253
0.0309
0.0172
0.00
0.00
13.97
14.07
10.17
13.36
13.36
14.23
0.00
W n-1/W n Fuel Burn
(lbs)
1.000
0.990
595
0.990
1,184
0.960
3,516
0.930
7,434
0.986
8,161
0.974
9,477
0.960
11,477
0.927
14,985
1.000
14,985
0.986
15,600
0.979
16,516
Fuel
(lbs)
595
589
2,332
3,918
727
1,315
2,000
3,508
615
916
Weight
(lbs)
59,488
58,894
58,305
55,972
52,054
51,327
50,012
48,011
44,504
44,504
43,889
42,973
Beta
1.000
0.990
0.980
0.941
0.875
0.863
0.841
0.807
0.748
0.748
0.738
0.722
AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
Appendix B – Mattingly “Master Equation” Validation of
FWD Tool
Validation data was provided by AE6343 TA’s and is shown here for completeness. The
blue line represents data calculated from the accompanying conceptual design tool. The
red dots are the validation points. Only one set of data is shown for brevity, the
remaining validation points are shown in the ‘Code Validation’ tab provided in the tool.
3.0
Validation Case 1: W/S and T/W
2.5
Calculated Using Mattingly Master Equation
2.0
T/W
Provided Validation Points
from GA TECH
1.5
1.0
0.5
W/S
0.0
0
50
100
150
FIGURE 15: FWD TOOL MATCHES VALIDATION POINTS
TABLE 14: VALIDATION INPUTS FROM GATECH AE6343
Validation Point 1
α
β
n
g
R
Velocity
q
CD0
K1
K2
dh/dt
dV/dt
0.33
0.57
2.6
32.2
0.001832
695
442.4509
0.019
0.25
0.005
35
1.8
W/S
ft/s2
slug/ft3
ft/s
psf
ft/s
ft/s2
25
T/W
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
2.791
1.5549
1.168
0.9933
0.9035
0.8562
0.8332
0.8253
0.8275
0.8368
0.851247
0.869554
0.890831
0.91444
0.939915
0.966907
0.995147
1.024428
1.054586
1.085488
200
AE6343-Aircraft Design I – Conceptual Design - SCAS
Michael Duffy, Oct 16th, 2007
References
[1] Jimenez, H., Griendling, K., 2006-2007 AIAA Graduate Team Aircraft Design
Competition – Modified RFP, Advanced Systems Design Lab, Georgia Institute of
Technology, Atlanta, GA, 2007
[2] Jimenez, H., Griendling, K., AE6343 Aircraft Design Project #1 – 2007, Aircraft
Constraint Analysis, Advanced Systems Design Lab, Georgia Institute of
Technology, Atlanta, GA, 2007
[3] Jimenez, H., Griendling, K., An Energy Based Approach to Aircraft Design,
Constraint Analysis – Part I, II, Advanced Systems Design Lab, Georgia Institute
of Technology, Atlanta, GA, 2007
[4] Mattingly, J., Aircraft Engine Design, 2nd Edition, AIAA Education Series, 2002
[5] Raymer, D., Aircraft Design: A Conceptual Approach, 3rd Edition, AIAA
Education Series, Reston, VA, 1999.
[6] Roskam, J., Airplane Design: Part I, Preliminary Sizing of Airplanes, Roskam
Aviation and Engineering Corporation, Ottawa, Kansas, 1985
26