DOC vs. Sweep

2010
DAR-20 Áscian Ray
Douglas A. Rieck
AME-481 Aircraft Design
USC Viterbi Engineering
5-14-2010

1.0 Mission Requirements Summary:
The Âscian Ray was designed to fill the role of a 200 passenger, medium range,
medium field length commercial airliner for introduction into the market in early
2020. It has been optimized to minimize direct operating cost under the conditions
and constraints tabulated below.
Passenger Capacity Goal 200
Limited Bulk Cargo 0 - 10000 lbs
TOFL (at MTOGW, standard atmosphere) < 8,400 ft
LFL (at max landing Weight, standard atmosphere)
ROC @ ICA and Max Cruise Altitude > 300 fps
Cruise Altitude Optimized for DOC
M cruise
2.0 Aircraft Geometry, Performance & Weights Summary
Lifting Surfaces Wing Horizontal Vertical Winglet
Area (ft 2 ) 1,200 396 532 51.2
Span (ft) 114.9 46.6 31 7
AR (n.d.) 11.0 5.5 1.8 0.96
Sweep (deg.) 28 35 40 35
Taper Ratio (n.d.) 0.46 0.30 0.30 0.35
Average t/c (n.d.) 0.10 0.09 0.09
Dihedral (deg.) 4 3 75
MAC (in.) 10.9 9.3 18.9
General Shape
Fuselage Length (in.) 1,960
Total Length (in.) 2,068
Diameter (in.) 198.0
Nose Fineness Ratio (n.d.) 1.8
Tail Fineness Ratio (n.d.) 3.1
Weight
OEW 87110 lb
MTOGW 160585 lb
Mission Payload 43000 lb
Bulk Cargo 5000 lb
Design Mission Fuel 23877 lb
Reserve Fuel 1601 lb
Total Usable Fuel 25478 lb
Optimized for DOC
Flight Conditions
Field Elevation 0 ft
Cruise Altitude 40000 ft
Vc 774 ft/s
0.8 -
M c
Cruise C L
Cruise L / D
0.66 -
16.2 -
Performance
TOFL 8159
LFL 4797
Min ROC @ Crz 398
Vldg Max
138
Vs1 164 kts
Range 3000 nm
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TOFL (ft)
14,000
12,000
10,000
8,000
6,000
4,000
2,000
Below is a chart depicting FAA Required Runway Length for the Ascian Ray in standard
atmosphere conditions at various altitudes and weight ranging from OEW to MTOGW.
Takeoff Runway Length Requirements
85,000 95,000 105,000 115,000 125,000 135,000 145,000 155,000 165,000
TOGW (lbs)
It can be seen that field length falls just under the 8,400 ft maximum length requirement
(see table above). Only departure from higher altitude airports will result in a higher
TOFL.
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Payload (lbs)
3.0 Comparison to Competition
80000
70000
60000
50000
40000
30000
20000
10000
The Ascian Ray’s payload capabilities may be marginally lower than the 737 for shorter mission
distances, it makes up for it. For all ranges approximately greater than the design range (3,000
nm) the Ascian Ray has a higher payload capability than the 737.
TOGW/(PaxNmi) Lbs/PaxNmi
0
1.400
1.200
1.000
0.800
0.600
0.400
0.200
0.000
Competing Aircraft Payload-Range Comparison
0 1000 2000 3000 4000 5000 6000 7000 8000 9000
Range (nm)
Commercial Transport, TOGW per passenger mile
Historical Trends 2001/02 AWST Data
1st Generation, Narrow Body TurboJets
Narrow Body Turbofans
Wide Body Turbofans
Supersonic Concorde M=2.0
Âscian Ray
0 2,000 4,000 6,000 8,000 10,000 12,000
Still Air Range (nmi)
Âscian Ray
Max Full Occupancy Range
737-900ER w/ winglets
737-700
767-200
MD-90-30/-30ER
757-200
The Ascian Ray also far outperforms other medium range airliners in weight efficiency.
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4.0 Configuration Description & Justification
The Acian Ray is a turbofan powered monoplane with wing mounted engines and a
conventional aft tail. The fuselage and wing structures take advantage of recent advances in
composite materials which reduces aircraft’s weight without sacrificing payload. The Ascian
Ray’s low MTOGW benefits L/D efficiency during flight and results in a lower cruise thrust
required. This translates to a reduced engine weight and size, further improving fuel
economy.
Two high bypass ratio turbofans are mounted to the rear edge of the wing struts slightly
inboard of the engine nacelles, each offering 32,000 lbs of SLST. The wings themselves are
swept aft at 28 degrees, to minimize structural weight, while still offering superior cruise
drag performance. The control surfaces on each wing consist of one inboard and one
outboard aileron, running 30% of the chord. High CL is achieved with one inboard and one
outboard single segment flap, and leading edge slats, also running 30% of the chord.
The vertical stabilizer takes advantage of a low mounted, double-hinged rudder to provide
sufficient yaw control for engine-out situations. The horizontal stabilizer is mounted further
aft to provide clearance from the vertical stabilizer’s structural spar and to avoid negatives
due to drag divergence. Both the horizontal and the vertical stabilizer are swept further
than the wing to reduce drag and prevent control reversal during high Mach dive situations.
The aircraft interior is divided into coach and business class, and offers a maximum capacity
of 209 passengers. The business class section takes advantage of a slightly unorthodox 2 by
2 by 1 seating arrangement to avoid wasted space while still adhering to aisle width
guidelines. Coach seating features a 2 by 3 by 2 seating arrangement with two aisles for
efficient navigation of the cabin by the potential 7 person crew. A twin aisle arrangement
also provides for more efficient emergency egress through the six exit doors. Two 42’’x72’’
exits are located at the forward galley and an additional two are located at the aft galley.
Ahead of the wings are two supplementary 24”x54” exits.
The nose of the plane was designed to elevate the pilots to a position where they have
sufficient viewing angles according to Mil-Std 850 guidelines for transport and cargo
aircraft. This is accomplished with a 10” step up to the cockpit floor level.
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5.0 Trade Studies
Cost/ton-nm ($)
TOGW (lbs)
0.600
0.580
0.560
0.540
0.520
0.500
155,000
152,500
150,000
147,500
145,000
142,500
140,000
DOC vs. Aspect Ratio
8 10 12 14 16 18
TOGW vs. Aspect Ratio
8 10 12 14 16 18
AR
AR
TOFL limit
Design Point
TOFL limit
Design Point
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Cost/ton-nm ($)
TOGW (lbs)
0.700
0.675
0.650
0.625
0.600
0.575
0.550
0.525
0.500
150,000
148,000
146,000
144,000
142,000
140,000
TOFL limit
ROC limit
Design Point
6 8 10
BPR
12 14
TOFL limit
TOGW vs. Bypass Ratio
Design Point
DOC vs. BPR
6 8 10 12 14
BPR
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Cost/ton-nm ($)
TOGW (lbs)
0.6500
0.6250
0.6000
0.5750
0.5500
0.5250
0.5000
154,000
152,000
150,000
148,000
146,000
144,000
142,000
140,000
DOC vs. Sweep
Cruise Buffet
Buffet @ ICA
TOFL limit
ROC limit
Design Point
10 15 20 25 30
Sweep (deg.)
35 40 45 50
TOGW vs. Sweep
10 20 30 40 50
Sweep (deg.)
Cruise Buffet
Buffet @ ICA
TOFL limit
ROC limit
Design Point
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This diagram demonstrates optimal sizing for the wing surface area and aspect ratio. The
final wing geometry was selected based upon this plot in conjunction with a number of
constraints, such as those in the previous charts.
Cost/ton-nm ($)
0.600
0.590
0.580
0.570
0.560
0.550
0.540
0.530
0.520
800
900
1000
DOC vs AR & Wing Area
1100
1200
1300
8
10
12
14
16
18
This snapshot of Jetsizer’s
Mission input page (left) shows
the results of the code and
includes checks for mission
constraints
The image shown shows the
results of an aircraft planform
that was run with intentionally
poor configuration in order to
demonstrate the constraint
checks.
Note: The Ascian Ray PASSED
these checks.
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C_L Buffet
L/D
18.000
16.000
14.000
12.000
10.000
8.000
6.000
1.40
1.20
1.00
0.80
0.60
0.40
0.20
0.00
L/D vs. C_L
0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
C_L Buffet vs. Mach
0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900
C_L
Mach
Crz
C_L Buffet
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6.0 Stability & Control
7.0 Cross-Section Drawing
\
Tail Geometry Horizontal Vertical
Volume Ratio 1.80 0.23
AR 5.5 1.8
Sweep (deg.) 5.5 1.8
t/c 0.09 0.09
Moment Arm (in.) 850.0 743.00
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8.0 Interior Arrangement Diagram
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9.0 Cockpit Three-View Drawing
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10.0 Jetsizer Configuration Page
Configuration Layout Image Control
481 Spring 2010
Douglas Rieck 0
Ascian Ray < Notes
< Notes
Plan View
Side View
Front View
Isometric View
Change Red Cells
Wing & Tails Wing Horiz. Vertical Winglet
Wing Area | Tail Volume Ratio, VH | VV = 1,200 1.80 0.236 NA n.d.
Axial Tail Pos'n (Xc/4-Xblkhd) = NA 120 140 NA in.
Aspect Ratio, AR | Winglet Height = 11.00 5.50 1.80 7.0 n.d.
Sweep Angle, c/4 = 28.00 35.00 40.00 35 deg
Planform Break Pos'n Ybreak/(b/2) = 0.4 0.00 0.00 NA n.d.
Break Taper Ratio Cbreak/Croot = NA 1.00 1.00 NA n.d.
Tip Taper Ratio, Ctip/Croot = 0.46 0.30 0.30 0.35 n.d.
Glove Extension at SOB, C/CSOB = 0.1 NA NA NA n.d.
Yehudi Extension at SOB, C/CSOB = 0.35 NA NA NA n.d.
Flap Chord Fraction Cflap/Cw = 0.25 0.35 0.35 NA n.d.
Area, total trapezoidal, S = 1,200 396 532 140
Span, b = 114.89 47 31 2
Wing Dihedral Angle, = 4 3.00 NA 75 deg
Vertical Offset, Z = -70 40.00 75.00 NA in.
Airfoil t/c @ SOB = 0.115 NA NA NA n.d.
Airfoil t/c @ Break = 0.100 0.09 0.09 NA n.d.
Airfoil t/c @ Tip = 0.085 NA NA NA n.d.
MAC Incidence Angle = 2.00 -1.00 NA NA deg
Axial Wing pos'n, Xc/4trap@C/L = 880.0 NA NA NA in.
1000
800
600
400
200
0
-200
-400
-600
-800
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11.0 General Arrangement Drawing
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12.0 Aircraft Systems Drawing
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