        program performance
c	
        implicit real*8 (a-h,o-z)
        real*8 LoverD,Wtot,Wfueltot,Wfuelcruise,eta,sfc,R,Vstall,
     ^  rhosea,Swing,Clmax
c
c       namelist /PerfInput/ LoverD, Wtot, Wfueltot, eta, sfc,
c    ^  Swing, Clmax
c
        open(3,file='PerfInput')
        read(3,*) LoverD, Wtot, Wfueltot, eta, sfc, Swing, Clmax
        close(3)
c
c       fuel weight estimation
c       unit conversion for specific fuel consumption
c
        Wfuelcruise=0.85*Wfueltot
        R=(eta*LoverD/sfc)*log(Wtot/(Wtot-Wfuelcruise))
        Range=R/5280.0
c
c       sea level stall speed
c
        rhosea = 0.002378
        Vstall=sqrt(2.*Wtot/(rhosea*Swing*Clmax))
c
        open(4, file='PerfOutput', status='unknown', form='formatted')
c
        write(4,*) ' '
        write(4,*) ' ===========  Performance Analysis ============ '
        write(4,*) ' '
        write(4,101) Wfueltot
 101    format( 'Total Weight of Fuel (lbs.) =', G15.6)
        write(4,102) Wfuelcruise
 102    format( 'Weight of Fuel Available for Cruise (lbs.) =', G15.6)
        write(4,*) ' '
        write(4,201) Range
 201    format( 'Max. Range (miles) =', G15.6)
        write(4,202) VStall
 202    format( 'Stall Speed (miles/hr) =', G15.6)
        close (4)
c
        stop
        end
