the b2 – bomber
TRANSCRIPT
TheB2–BomberACloserLookattheB2Configuration
DavidCross,JoelFaber,andRaulTelles
AOE4124–TeamProject
April1,2009
BriefHistory• TheB‐2isarevolutionaryaircraft• Uniqueflyingwingconfigurationwiththefollowingdesignobjectives
– Serveasamulti‐rolebomber– Stealthwasextremelyimportant– Hadtobeabletoflylongmissions
• Development– Beganinthe1970s– FirstoffthelineinNovemberof1988– FirstFlightwasJuly17,1989– In1991,B‐2designteamwasawardedtheCollierTrophy
• B‐2inAction:– 1999inKosovo– 2001inAfghanistan– February22,2008,firstreportedaccidentofB‐2– Humidityonsensorswereyieldingskewedpre‐flightchecks
Jane’sMilitaryAircraftRecognitionGuide,2007
SpecificationsFirstflight: 17‐Jul‐89Classification: BomberSpan: 172feetLength: 69feetGrossweight: 336,500poundsCruisingspeed: HighsubsonicRange: 6,000milesplusCeiling: 50,000feetPower: Four19,000‐pound‐thustF118‐GE‐100enginesAccommodation: 2crewArmament: Morethan40,000‐poundnuclearorconventionalweaponpayloadRunwayLength: 6500feetCost: $2billion
Jane’sMilitaryAircraftRecognitionGuide,2007
(67.28,0)
(48.20,43.84)
(56.75,13.00)
(59.63,86.00)
(69.80,72.60)
(63.15,21.34)
(0.0,0.0)
GeometryPlanformArea: 5118.55ft2
MeanAerodynamicChord: 39.47ftX‐Centroid: 40.21ftSpanwisepositionofMAC: 29.53ftX‐LeadingEdgeofMAC: 20.47ftQuarterChordofMAC: 30.34ftAspectRatio: 5.78AverageChord: 29.76ftTaperRatio: 0.00LESweep: 34.74deg
PictureSource:http://www.aerospaceweb.org/aircraft/bomber/b2/b2_schem_01.gifDataSource:UtilizedWingPlanAnalCodetogeneratedata
CGlocation
CGlocationwascalculatedbylookingatthesideprofileoftheB‐2.
Assuminga15°anglebetweenthelandinggeargroundcontactandthecglocationandassumingthecgwaslocatedforwardofthelandinggear,thecgwascalculatedtobearound33.2feetaftofthereferencedatumline.
NeutralPoint:32.98ftaftofnose
StaticMargin:0.22ft
ReferenceDatum
NP
PictureSource:http://www.aerospaceweb.org/aircraft/bomber/b2/b2_schem_01.gifDataSource:UtilizedVLMpcCodetogenerateneutralpointdata
x
z
CdoatVariousAltitudes
DataSource:UtilizedFRICTIONcodefromhttp://www.aoe.vt.edu/~mason/Mason_f/MRsoft.html
M=0.79
NotebyMason,thiswasrunatadifferentaltitude(Re)
SpanloadingComparison
DataSource:UtilizedLIDRAGCodefromhttp://www.aoe.vt.edu/~mason/Mason_f/MRsoft.html
e=0.96
Cl=1
TwistDistributionforMinimizedDrag
DataSource:UtilizedLAMDESCodefromhttp://www.aoe.vt.edu/~mason/Mason_f/MRsoft.html
OptimizedSpanloading
DataSource:UsedspanloadingdataoutputfromLAMDESprogramfoundathttp://www.aoe.vt.edu/~mason/Mason_f/MRsoft.html
SectionClforB2
DataSource:UtilizedVLMpcCodeoutputforsectionCL’sfromhttp://www.aoe.vt.edu/~mason/Mason_f/MRsoft.html
CLatVariousAltitudes
DataobtainedfromLiftequationatMach=0.79andthecorrespondingdensitiesforeachaltitude.
Lift–to–DragRatio
DataSource:http://www.aoe.vt.edu/~mason/Mason_f/ConfigAeroAppD.pdf
TakeoffandLanding
• Groundeffect:- Largeareaflyingwing- Sitsoncushion- Hastobe“forced”toland- Notdifficult(2ndeasiesttotheF‐15)• Stealthdesignledtogreatliftingfeatures.
ControlSurfaces• B‐2has4pairsofcontrolsurfaceson
thewingtrailingedge.
1)Splitdragruddersonouterwing2)Oneelevononouterwing3)Twoelevonsoninnerwing4)Beavertail
• Outerelevonsprovideprimarypitch&rollcontrol.
• 2innerelevonsconsideredsecondarycontrolsurfaces(usedatlow‐speed).
• Beaver‐tailworksconstantlytoalleviategustloads. Atlowspeedflight,dragrudders
areopen.PictureSource:http://people.clarkson.edu/~pmarzocc/AE430/AE‐430‐5.pdfhttp://people.clarkson.edu/~pmarzocc/AE430/AE‐430‐5.pdfStabilityandControlofConventionalandUnconventionalAircraftConfigurations:ByBerndChudobaPage201http://science.howstuffworks.com/stealth‐bomber2.htm
Stealth
LowObservableCharacteristics
‐RADARcrosssection(RCS)
‐Infraredsignature
‐Appearance
‐ElectromagneticSignature
‐AcousticSignature
Picturesource:
http://www.is.northropgrumman.com/systems/b2spirit_assets/photos/hi/01top20_94a65408.jpg
Stealth
• ThekeytoStealthisknowhowRADARwavesarereflectedoffabody.
• RADARwavesreflectsimilartolightrays.
• Alightraywillreflectoffasurfacethesameangleatwhichitencounteredthesurface.
• TogetareturnaRADARreflectionrequiresasurfaceperpendiculartotheincomingwave.
θ θ
ReferenceData:http://www.aoe.vt.edu/~mason/Mason_f/ConfigAeroStealth.pdf
http://www.answers.com/topic/stealth‐aircraft
http://en.wikipedia.org/wiki/B‐2_Spirit
Stealth
TheB‐2outerprofilehasavariableradius/continuouscurvethatdeflectsRADARwavesatanyangle(non‐tangentialsurface).Thus,reducingit’sRCS.
It’sshapealsoallowsforaerodynamicflow.
Tofurtherreduceit’sRCStheskiniscoatedwithRADARAbsorbingMaterials(RAM)
Transmitter/receivers
target
PictureSource:
http://www.is.northropgrumman.com/systems/b2spirit_assets/photos/hi/01top20_95020910.jpg
ReferenceData:InsidetheStealthBomberByBillSweetman(page25‐26)
http://www.answers.com/topic/stealth‐aircraft
http://en.wikipedia.org/wiki/B‐2_Spirit
QUESTIONS???
Picturesource:GoogleImagesSearch“B2”