Team One

XT-1 GlobetrotterTeam Members: Saverio Rotella (Team Leader), Taylor Berry, Jeremy Bushey, Javier Esquivel, Geoff

Fishering, Walter Glowicki, Christopher Schwall, Daniel Steinbaugh

Outline of CDR

2 Sam

-Project Mission and Target Market -Propulsion-Design Mission and Design Requirements -Structures-Best Aircraft Concept -Weights and Balance-Aircraft Sizing and Carpet Plots -Stability and Control-Design Trade-offs -Environmental Impact-Aircraft Description -Autonomy-Aerodynamics -Cost-Performance Summary -Summary

Project Mission and Target Market

• Project Mission– Carry 100,000 lbs– Travel 6,500 miles– Cruise at Mach 0.85– Reduce Environmental Impact to N+2

Standards as set forth by NASA• Target Market

– Primary Customer would be United States– Aiming to replace C-17

Sam3

Design Mission and Design Requirements

• Design Missions– Take-off <5,000 ft– Range: 6,500 mi

• Altitude: 3,000 ft• Mach 0.85• No Refueling

– Payload: 100,000 lb– Landing <3,000 ft

• Requirements– Minimum Range of 6,500 miles– Cruise at Mach 0.85– Carry a minimum of 100,000 lb– Meet N+2 standards set forth by NASA– Consider Autonomy

4 Sam

Aircraft Concept Improvements

•Reduction in noise and Nox emissions•Reduction in fuel burn by 40% compared

to C-17 ferry mission.•Reduced induced drag by 10% by

incorporating Box Wing design.• Shorter take-off distance• Engines mounted above wing to protect

from ground debris and noise shielding

5 Chris

Aircraft Walk-Around

Double-Bubble Fuselage: -Added Lift -Added Cargo Volume

Boxed Wing: -Reduced Induced Drag -Higher Effective AR -Reduce Structural Weight -Added Fuel Storage

Above-Wing Engines: -Debris Shielding -Noise Shielding

Landing Gear Fairings : -Reduce Noise -Reduce Drag

Chevrons: -Noise Reductions

Ultra Compact Combustor/Counter-Rotating Turbine: -Increase Engine Efficiency -Reduce Fuel Burn

High T-Tail: -Reduce Takeoff distance -Increase Loadability Ramp:

-Easy loading

Supercritical Airfoil: -Improved transonic performance

Jeremy

Final Design Weights & ParametersDesign Values XT1 GlobetrotterTOGW 499,500 lb

Empty Weight 275,000 lb

Typical Range 5,600 nmi (6500 mi)

Typical Payload 100,000 lb

Max. Range 10,100 nmi

Max. Payload 170,000 lb

Take-off Distance 4,850 ft.

Landing Distance 2,950 ft.

Acquisition Cost (USD 2012) $ 180,000,000

Operating Cost (USD 2012) $ 800,000/Year

Development Cost (USD 2012) $ 5,730,000/AC

Design Parameter

Thrust -to-weight 0.27

Wing Loading 130 lb/ft^2

Wing Sweep 25 deg.

Wing Span 156 ft.

Aspect Ratio 8.3

Climb Rate 2000 ft/min

Cruise Mach 0.83-0.85

Cruise Altitude 28,000 ft.

Clmax 2.9

MAC 17 ft.

7Chris

Sizing CodeDevelopment

8

Sizing Code• Iterative MATLAB script using computed TOGW• Features:

– Fuselage dimensions from Payload layout– VSP calculated Fuselage wetted area– Wing/Engine wetted area calculations and

weight calculations from Raymer for Tube and Wing

– Box wing modifications and calculations were self determined.

– Drag Component Build-up

Taylor9

Fuselage Sizing

• Determine dimensions of payload section• Add clearance• Other important dimensions:

– Cockpit– Ramp– APU– Lavatory

• Geometrically Determine necessary nose/tail lengths• Length, diameter of fuselage calculated

Taylor10

Fixed Performance Parameters

•CL_max = 2.9– Based on Airfoil, Implemented HLD’s

• t/c = 0.12– Supercritical Airfoil

•Wing Sweep: 25 degrees– To prevent transonic wave drag

• Taper Ratio: 0.4– Chosen from calibration of C-17

Taylor11

Box wing Estimation

• In the sizing code the box wing was treated as two separate wings as shown to the right.

• The wing area for bottom was calculated by assuming the wing will need to lift ~60% of the aircrafts weight.

• The wing area for the top wing was calculated by assuming that the wing will need to lift the remaining ~40% of the aircraft.

• The wing weight was then calculated for both of the wings separately and added together.

Photo provided by: Khan, Fahad A., Luleå University of Technology, Preliminary Aerodynamic Investigation of Box-WingConfigurations using Low Fidelity Codes.

12 Chris

Sizing Code Calibration Using the C-17 Globemaster

Aircraft Specifications

C-17 Globemaster III

Results from Sizing code

Percent error[%]

Fuselage Length 174 [ft] 174 [ft] Input Parameter

Wing Span 169 [ft] 156 [ft] 7.6

Wing Area 3800 [ft^2] 3400 [ft] 10.5

Horizontal Tail Area 845 [ft^2] 950[ft^2] 10.9

Empty Weight 276500 277600 0.39

TOGW 585000 509100 12.9

The aircraft was calibrated using our modified engine deck and code which was researched and predicted to reduce the fuel consumption by ~10%. This results in the TOGW to be less than the actual which the code found it to be ~13% lighter.

13 Chris

Concept ComparisonDouble Bubble Box WingTakeoff Gross Weight: 499500 lbs Fuel Weight: 123900 lbs Payload Weight: 100600 lbs Empty Weight: 275000 lbs ------------------------------------------------------------ Empty Weight breakdown ------------------------------------------------------------ Wing: 86078 lbs Fuselage: 56345 lbs Vtail: 1719 lbs Engines: 24714 lbs Gear: 21438 lbs Misc: 84757 lbs ------------------------------------------------------------ Costs : Acquisition Cost : $ 180,000,000 (USD 2012)Operating Cost: $ 800,000 (USD 2012)Performance:Takeoff Distance: 4850 ft.Landing Distance: 2950 ft.

Elliptical Tube and WingTakeoff Gross Weight: 564592 lbs Fuel Weight: 162184 lbs Payload Weight: 100600 lbs Empty Weight: 301808 lbs ------------------------------------------------------------ Empty Weight breakdown ------------------------------------------------------------ Wing: 87613 lbs Fuselage: 53785 lbs Vtail: 4624 lbs Htail: 7391 lbs Engines: 28295 lbs Gear: 24245 lbs Misc: 95854 lbs ----------------------------------------------------------- Costs : Acquisition Cost : $ 197,000,000 (USD 2012)Operating Cost: $ 890,000 (USD 2012)Performance:Takeoff Distance: 5200 ft.Landing Distance: 3200 ft.

14 Chris

Cross-Plots

40 60 80 100 120 140 16020

30

40

50

60

70

80

90

100Specific Excess Power Cross-Plots

Wing Loading (lb/ft2)

Spe

cific

Exc

ess

Pow

er (l

bf)

T/W = .3T/W = .25T/W = .2

40 60 80 100 120 140 1601000

1500

2000

2500

3000

3500Landing Distance Cross-Plots

Wing Loading (lb/ft2)

Land

ing

Dis

tanc

e (ft

)

40 60 80 100 120 140 1601000

2000

3000

4000

5000

6000

7000

8000

9000Takeoff Distance Cross-Plots

Wing Loading (lb/ft2)

Take

off D

ista

nce

(ft)

T/W = .2T/W = .25T/W = .3Ran code for wing loading range of 40

to 160 pounds per square foot at three different thrust-to-weights: .2, .25, and .3. This gave a range of design points to be plotted on final carpet plot.

Jeremy15

Carpet Plot

80 90 100 110 120 130 140 150 160 170 1805

5.2

5.4

5.6

5.8

6

6.2

6.4x 10

5 Thrust-Weight Carpet Plot

W/S [lb/ft2]

WTO

[lb]

T/W = 0.2T/W = 0.25T/W = 0.3distTO < 5000 ft

Specfic Power > 50Design Point

Constraints:-Specific Power > 50 -Takeoff Distance < 5000 ft-Landing Distance < 3000 ft

Design Point:-Wing Loading of 130 pounds per square foot-Thrust-to-Weight of .27-TOGW of 499500 lbs

16 Chris

Fuel Efficiency Trade-off

The Fuel efficiency for the C-17 was calculated from ferry.

Our constraint is to burn 50% less fuel than the C-17 on the same typical mission but information was unavailable.

Assuming that the ferry efficiency is the most efficient full burn then the design point was chosen to be within 40-50% of the ferry efficiency.

Design Point: W/S = 130 lb/ft^3T/W = 0.27

0 20 40 60 80 100 120 140 160 18015

20

25

30

35

40

45

50Fuel Burn Carpet Plot

W/S [lb/ft3]

Fuel

Effi

cien

cy [l

b/nm

i]

T/W = 0.2T/W = 0.25T/W = 0.3Fuel/nmi < 50% C-17Fuel/nmi < 40% C-17Design Point

17 Chris

Design Trade-offs

• Box wing reduces induced drag and has a lower structural weight but results in a small increase in parasite drag.

• T-tail decreases drag due to endplate and increases rate of pitch but increases structural weight.

• Engines on top allow for noise reduction and debris shielding but increased maintenance.

• Electric Taxi decreases fuel burn but increases the empty weight.

• Double bubble allows for increase in lift from the fuselage but increases the parasite drag.

• Technology trade-offs are examined in the Propulsion section.

18 Chris

Final Aircraft Dimensions

161 ft.

133 ft.

19Jeremy

Fuselage Layout

L = 161 ft.

D = 32 ft.

= 463L Master Pallets

= Landing Gear

= Loading Ramp

Component Length (in) Width (in)Pallet 108 88

Ramp 234 216

15 ft.

Taylor20

Aerodynamics

• Airfoil selection, wanted to select a supercritical airfoil to delay effects of drag divergent Mach number.• Starting point was C-17 airfoil: sc(2)-0412• More lift created using the sc(2)-0612 ~ 10%

Geoff21

High Lift Devices

• Implementing two high lift devices: -Slats -Triple Slotted Flaps:

max1.9lC

max.4lC

Values from Raymer Table: 12.2

Geoff22

CL Max

• Sc(2) – 0612 :• Addition of slats:• Addition of triple:• Total:

max1.264lC

max.4lC

max1.9lC

max3.564lC

max max .25.9 cosL l cC C Equation 12.15

max2.9LC Final Value:

Geoff23

Code Drag Prediction

• Total drag equals summation of two separate forms:

•Need these values in order to compute final drag, that value is used in our weight and fuel codes.

0iD D DC C C

Geoff24

Parasite Drag

•Component Build Up

• Allows for drag calculation during different stages, but cruise conditions were used for fuel predictions.• Allows calculation of pressure drag

caused by large upsweep at the rear of the aircraft.

0 &

( )c

misc Wave

fc c c wetD D DL P D

ref

C FF Q SC C C C

S

Raymer (12.42)

Geoff25

Wave Drag

CDW

0CDW .002

Geoff26

Comparison

• Verify results by comparing to initial estimates from Raymer.

• Initial estimate = .0355• Final estimate using component build

up, plus wave and misc. drag = .0325

CD0 C feSwetSref

Raymer (12.23).0035feC

Geoff27

Induced Drag

•Use equation 5.62 from Anderson

2

( R)ei

LD

CCA

.67LC

Using our calculated vales of AR = 8.3, and e = .6822

.0231iD

C

Geoff

0.0586

iD D DC C C

28

Performance SummaryDesign Values XT1 GlobetrotterTypical Range 5,600 nmi (6500 mi)

Typical Payload 100,000 lb

Max. Range 10,100 nmi

Max. Payload 170,000 lb

Take-off Distance 4,850 ft.

Landing Distance 2,950 ft.

Climb Rate 2000 ft/min

Cruise Mach 0.83-0.85

Clmax 3

Thrust -to-weight 0.27

28 Chris

Tech

• Engine:– Ultra Compact Combustor [1, 2, 3]

• Increased efficiency, reduced emissions, reduced engine length– Counter-Rotating Turbine [4, 5]

• Reduced pressure losses, increased efficiency– Chevrons [6, 7]

• Decreased noise– Scarfed Inlet [8]

• Noise deflection, debris ingestion shielding, improved performance at positive AoA

– Frequency Adjustable Acoustic Liners [9]• Improved noise performance

• Other:– Lading Gear Fairings [10]

• Reduced drag and noise– Electric Taxiing [11, 12]

• Reduced emissions and fuel consumption

http://it.wikipedia.org/wiki/File:Boeing_787_engine_chevrons.jpg

Figure from Reference [3]

Dan30

Engine Description

• High bypass geared turbofan with ultra compact combustor and counter rotating turbines– B=14.3– OPR=42– FPR=1.5– Low CPR=2.33– High CPR=12– Gear ratio = 2.0– Engine deck Tsls = 23369.2 lb with SFC = 0.2569

Data from ref [13]Dan31

Modeling the engine

• Using engine deck from NASA, found efficiencies at design condition using 1D equations interation• Changed the efficiencies to reflect the new tech

and added inlet and nozzles with typical efficiencies• Using outputs from 1D eqns, scaled engine

deck to reflect new tech and installation losses• Validated scaling using Raymer:

– 1% pressure loss at inlet = 1.3% specific thrust loss

Dan32

V-n Diagram

0 200 400 600 800 1000 1200-3

-2

-1

0

1

2

3

Equivalent Speed (ft/s)

Load

Fac

tor

Sam33

Important Load Paths

Sam34

Wing-Fuselage Intersection and Engine Pylons

•Wing Fuselage Intersection– Front wings

• Low wing carry through• Connects to longerons

– Back wings• High wing carry through• Connects to T-tail

• Engine Mounts– Attaches to top of wing to front spar

Sam35

Landing Gear

Gear Set Length (ft) Width (ft) Height (ft)Main Gear 10.2 4.2 5

Nose Gear 3.55 4.85 3.55

Main Gear: 2x3 bogey (from 777)

*Sized using Raymer Chapter 11 Sam36

Materials Selection

• Steel– Spars, longerons, keelson, landing gear,

and wing attachments• Aluminum-2024

– Skin of aircraft, stringers, engine pylons, flaps, etc.

Sam37

Aircraft Group WeightsStructures Weights, lb Loc., ft Moment, ft-lb Equipment Weights, lb Loc., ft Moment, ft-lb

Wing 86077.64703 60.87 5239546.375 Flight Controls 81.56 80.56 6570.242097

Vertical tail 1719.326071 147.7 253944.4607 APU 1,320.00 159.34 210328.8Fuselage 56345 70.62 3979083.9 Electrical 1,762.85 80.56 142015.5007

Main Landing Gear 17150.75811 60.98 1045853.229 Avionics 1,840.27 9.27 17059.29197

Nose Landing Gear 4287.689527 27.81 119240.6457 Anti-icing 999.09 60.87 60814.786Load and handling 1,584.00 68.11 107886.24

Propulsion Weights, lb Loc., ft Moment, ft-lbEngine(s) - installed 24713.5 71.7 1771957.95 Useful load Weights, lb Loc., ft Moment, ft-lb

Engine Controls 46.69651544 71.7 3348.140157 Crew 600.00 10 6000

Starter 285.9980757 71.7 20506.06203 Fuel - usable 123,895.88 57.42 7114101.43

Fuel System/tanks 343.2067933 80.56 27648.73927 Cargo/Payload 100,600.00 72.14 7257284

TOGW 499546Empty Weight breakdown ____________________________________ Wing: 86078 lb Fuselage: 56345 lb Vtail: 1719 lb Engines: 24714 lb Gear: 21438 lb Misc: 84757 lb

38 Javier

C.G. Calculation

39 Javier

Stability and Control

40 Javier

C.G. Travel Diagram

41 Javier

•Using historical data from Raymer, volume coefficient eqns used– Elevator C_e/C_ht=.25, b_e=.9*b_ht

(assumed normal T-tail)– Aileron C_a/C_w=.15 to .25, b_a=.4b_w

positioned .5b_w to .9b_w– Rudder C_r/C_vt = 0.35, b_r = .9b_vt

Dan42

Fuel Burn

• Calculated when aircraft is acting as a Ferry

* Fuel Burn Measured in lb-Fuel/nmi

Fuel Burn ReductionGlobetrotter 19.75 -------

C-17 38.06 48%

777-200ER 34 44%

Walter43

NOx Reduction

• NOx Calculation done by Matlab Code• Equation to Calculate NOx (From Gas Turbine Combustion:

Alternative Fuels and Emissions) [4]

Emissions (g/kN) = (NOx Index + Fuel Flow + Time In Mode) / Max Thrust at Sea Level

Percent Below CAPE/6 = 71%

• Use of geared turbofan engine combined with compact combustor led to reduction in Nox

• Total NOx Emissions (with cruise included) = 34.67 (g/kN)

CAPE / 6 63.36Ours 18.35

Walter44

Noise Reduction

• Features used to reduce community noise– Geared Turbofan [1]

• 22 EPNdB approximate cumulative reduction– Noise Shielding [2]

• 20 EPNdB approximate cumulative reduction (tested with chevrons)

– Landing Gear Fairings• 4.50 EPNdB approximate cumulative reduction

– Acoustic Liners• 3 EPNdB approximate cumulative reduction

Walter45

Aircraft Noise Estimation

• Roughly Followed Professor Kroo’s Noise Calculation method set fourth in his Aircraft Design, Synthesis, and Analysis Book [3]

• Use Boeing 747-400 Freighter as baseline data (ICAO Noise Database)

Total Cumulative Noise Reduction: 49.5 EPNdB

* Aircraft Noise Estimation Estimation = 40 + 10 log W

Sideline EPNdB

Take Off EPNdB

Approach EPNdB

Baseline 99.7 101.5 104.7Geared Turbofan -7.333 -7.333 -7.333Noise Shielding 0 -5 -15Acoustic Liners -1 -1 -1Landing Gear Fairings

0 -2.25 -2.25

Airframe Noise* -1.8684 -1.8684 -1.8684Total 89.507 84.0486 79.117

Walter46

Autonomy

• Three options for approaches:– Completely Autonomous– Remove one pilot and replace with an

autopilot– Do nothing in terms of Autopilot

• Issues with autonomy:– Technology– Safety– Integration amongst civilian population

Sam47

Cost

• Currently 239 C-17s in service that are operated by the United States government• Throughout course of production, the C-17’s

will have accumulated 30 years of service and will need to be retired or upgraded at a significant cost

Cost Dollars (2012)Developmental 6 Mil

Acquisition 180 Mil

Operating 800,000

Sam48

Cost Calculation Methods

• Equations were taken from Aircraft Design: A Conceptual Approach, 4th Edition, by Daniel Raymer•Calibrated acquisition cost to the cost to

purchase a C-17, then used calibration factor to calibrated operating cost as well

Sam49

Summary

50 Sam

Compliance MatrixFinal Compliance Matrix

Requirement Target Threshold Double Bubble

Range (w/ max payload) 2200 nmi 1800 nmi 2,400 nmi

Range (w/ typical payload) 6517 nmi 5648 nmi 5,648 nmi

Max Payload 195,000 lb 160,000 lb 170,000 lb

Typical Payload 130,000 lb 100,000 lb 100,000 lb

Cruise Mach Number 0.85 >0.74 0.85

Landing Field Length <3,000 ft <3,500 ft ~2950ft

Takeoff Field Length <5,500 ft <6,000 ft ~4900 ftDesign Mission Fuel

Burned<107,600

lb <129,100 lb *123,600 lb

Acquisition Cost <$202M <$240M $180M

= Equal to/Greater Than Target = Beats Threshold, Does not meet Target = Does Not meet Threshold

*=Based on FerryChris

51

Future Work

•Drag Polars for airplane• Find a better way to determine

aerodynamic center of box wing• Further analysis on noise reduction and

NOx emission•Re-adjust Landing Gear•Determine Lift generated from body

52 Sam

References

[2] Envia, E. “Emerging Community Noise Reduction Approaches,” 3rd AIAA Space Environments Conference, AIAA, Honolulu, HI, 2011

[1] “Pure Power PW1000G Engine,” Pratt and Whitney, East Hartford, CT, [http://www.purepowerengine.com/]

[3] Kroo, I.,“Aircraft Design: Synthisis and Analysis,“ Stanford University, California, 2006. [http://adg.stanford.edu/aa241/AircraftDesign.html Acessed 4/2/2012]

[4] Lefebrve, A., Ballal, D. Gas Turbine Combustion: Alternative Fuels and Emissions, Taylor and Francis Group, Boca Raton, FL, 2010.

53

References

1. Donald D. Johnson, Marc D. Polanka. Air Force Institute of Technology, WPAFB, Ohio, 45433, U.S.A. Cooling Requirements for an Ultra-Compact Combustor AIAA 2012-0948

2. Zelina, J. Ehret, R. D. Hancock, D. T. Shouse and W. M. Roquemore, G. J. Sturgess. Air Force Research Laboratory WPAFB, OH 45433. ULTRA-COMPACT COMBUSTION TECHNOLOGY USING HIGH SWIRL FOR ENHANCED BURNING RATE AIAA2002-3725

3. Alejandro M. Briones, Joseph Zelina, Viswanath R. Katta. Flame Stabilization in Small Cavities. AIAA 44162-759 4. David Lior. Technion, Institute of Technology. Haifa, Israel 32000. Rafael Priampolsky. Becker Engineering ltd. –

Rehovot, Israel 76706. Stator-Less Turbine Design. AIAA-2005-4220-4005. Qingjun Zhao, Jiafei Qiao, Huishe Wang, Xiaolu Zhao, and Jianzhong Xu. Institute of Engineering Thermophysics,

Chinese Academy of Sciences 1, Beijing, 100190, China. Experimental and Numerical Investigation on Flow Characteristics of a Vaneless Counter-Rotating Turbine at Off-Design Conditions. AIAA-2009-4835-346

6. http://www.aviationweek.com/aw/generic/story.jsp?channel =awst&id=news/awst/2012/01/16/AW_01_16_2012_p21- 413463.xml&headline=Surprising%20Designs%20For%20E co-friendly%20Airliner&next=10

7. http://www.nrl.navy.mil/media/news-releases/2011/nrl- researchers-study-ways-to-reduce-jet-aircraft-noise8. Donald S. Weir, Bruce Bouldin†, and Jeff M. Mendoza. Static and Flight Aeroacoustic Evaluations of a Scarf inlet.

Honeywell Engines, Systems, and Services, Phoenix, AZ, 85072, USA9. Michael Perrino, Jeff Kastner, Ephraim Gutmark, Sivaram Gogineni. Towards Development of an Active Single-

Layer Acoustic Liner for Jet Engine Noise Reduction. University of Cincinnati, Cincinnati, OH, 45221 10. Perforated Fairings for Landing Gear Noise Control - K. Boorsma and X. Zhang N. Molin – AIAA11. http://www.nasa.gov/topics/aeronautics/features/greener_aircraft.html12. http://honeywell.com/News/Pages/Safran-and-Honeywell-Commence-Electric-Green-Taxiing-System-Testing.aspx13. Mark D. Guynn, Jeffrey J. Berton, Kenneth L. Fisher, William J. Haller, Michael T. Tong, Douglas R. Thurman.

Refined Exploration of Turbofan Design Options for an Advanced Single-Aisle Transport. Glenn Research Center, Cleveland, Ohio

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