










                PROP OPTIMIZER INPUT DEFINITIONS








































                      PROP OPTIMIZER PROGRAM                          
          Copyright 1993 Donald R Bates - All Rights Reserved
    BATES ENGINEERING, 2742 Swansboro Road, Placerville, CA 95667
                       Phone/FAX 916-622-1886


                PROP OPTIMIZER INPUT DEFINITIONS



  ----------------------------------------------------------------------------
  CONTROL

  NPAYOFF Select design objective merit function for optimization:            
          0 - ADRAG and BACAL flight calibration                              
          1 - Point design analysis (may vary RPM only using IOPT=3)          
              Calculates point performance for one set of design variables.   
          2 - Maximum VCRS (cruise velocity)                                  
                                                                              
          NOTE: PROP OPTIMIZER Advanced has additional options to find the    
                maximum rate of climb and minimum horsepower required for a   
                given design cruise speed.                                    

  IOPT    Select one or more design variables to be optimized:                
          1 - AFDES, Activity Factor per blade                                
          2 - DIAM, Propeller diameter                                        
          3 - RPM, Engine RPM                                                 
          Variables not selected remain fixed for the duration of the run.    
          Example: IOPT=1,2,3 allows activity factor, diameter and engine     
          speed to be varied by the optimizer while reduction factor is fixed.
                                                                              
          NOTE: PROP OPTIMIZER Advanced has additional options to find the    
                optimum speed for maximum rate of climb and optimum gear      
                ratio for geared engines.                                     

  PDES    Selects radial pitch angle distribution for design output:          
          0 - Constant geometric pitch distribution (default).                
          1 - Constant angle-of-attack pitch distribution for slender nose or 
              pusher (KS must equal 1 for a pusher) and better efficiency.    
          2 - Constant angle-of-attack pitch distribution for blunt nose.     


  ----------------------------------------------------------------------------
  DESLIM

  AFLIM   Lower and upper bounds on the single blade activity factor, AFDES.  
          The default is 60 to 150 which is about the practical range. If     
          the optimizer can not converge to a solution in the desired range   
          different try different limits.                                     

  DLIM    Minimum and maximum diameter limits, inches                         

  TDMAX   Maximum blade thickness/diameter ratio to prevent excessive hub     
          thickness. A value greater than zero must be input to trigger blade 
          airfoil coordinates output.                                         


  ----------------------------------------------------------------------------
  DESVAR

  ABDES   The minimum design blade angle-of-attack for cruise referenced to   
          the zero-lift-line. This prevents the propeller design from being   
          too lightly loaded. Normally, you will want to run the propeller at 
          the angle for best efficiency which the program automatically finds 
          if ABDES=0 or is omitted. This usually gives the propeller blade a  
          lift coefficient in the minimum drag range. This is about CL=0.2 and
          an angle-of-attack of about 1.2 degrees for the Clark Y airfoil.    
          You can determine the loading angle of your present propeller by    
          running the ADRAG calibration.                                      

  ADRAG   Equivalent flat plate drag area of your aircraft in square feet.    
          (Typically: F-51 Mustang= 2.7, Cassutt= 0.9, Miller JM-2= 1.0,      
          KR-2= 1.4, Q2= 1.5, Falco= 2.2, RV-6A= 2.3, Varieze= 1.75).         
          With test flight speed, power and propeller known, ADRAG can be     
          determined using NPAYOFF=0. This option computes ADRAG based on the 
          power required calculation at a recorded cruise performance point,  
          i.e., at ALTCRS, RPMREF which defines the horsepower produced and   
          delivered to the propeller and VDES is the recorded cruise velocity.
          ADRAG is used to calculate the parasite drag component of the total 
          drag. Total drag is parasite + induced + slipstream drags. WTGRSS,  
          SPAN and KS are needed to calculate ADRAG and the total drag.       

  AFDES   The initial design single blade activity factor. When input, AFDES  
          makes the program start with this value. The resulting propeller    
          is scaled from the input or default CHORD values. Otherwise, AFDES  
          is calculated from the input CHORDs or the default NACA propeller.  
          The practical range is about 60 to 150 per blade.                   

  ALTCRS  Density altitude for optimized cruise propeller design, feet        

  BACAL   Calibration increment to the rated blade angle at 75% tip radius.   
          When BACAL is input, the program outputs both effective and rated   
          pitch. To determine BACAL, use the NPAYOFF=0 input option and input 
          propeller data recorded for cruise performance at maximum power.    
          BACAL is used as a reference to relate the manufacturer's airfoil   
          and pitch measurement to the program output. If not known, BACAL    
          is usually in the 1-5 degree range and approximately the zero lift  
          angle-of-attack with the opposite sign.                             

  KS      Propeller slipstream constant for drag generated on other aircraft  
          components. Drag added is KS*CT/J^2 times parasite drag. KS varies  
          from 1 for tail mounted pushers to 13 for a very clean streamline   
          body. NACA TR 640 suggests 2.5 for 1938 vintage aircraft. Modern    
          homebuilt tractors may be slightly higher, possibly about 3, and    
          powered self-launch sailplanes slightly lower due to the large      
          wing area outside of the slipstream.  The high value for clean      
          streamline bodies is due to the relatively low drag without the     
          propeller compared to the added drag due to the slipstream effect.  
          This term may be negated by setting KS to zero but there is much    
          test data to support it and 2.5 is the program default.             
          NOTE: PROP OPTIMIZER Advanced can determine KS automatically.       

  DIAM    Initial propeller diameter, inches                                  

  DREF    Reference propeller diameter, inches, for calculating the efficiency
          correction for diameter changes. It is the diameter of the propeller
          used to determine ADRAG for the reference performance calibration.  


  OSWALD  Aircraft efficiency factor due to W.B.Oswald. This term directly    
          affects induced drag. If the aircraft designer does not provide     
          this value, most aircraft are in the 0.70-0.95 range and you may    
          omit this input and use 0.825 the program default. This term has    
          about a 1% effect on cruise performance since induced drag is small 
          at high speeds and maybe about a 5% influence on climb performance  
          for relatively moderate climb speeds. In the August 1993 issue of   
          the EAA Experimenter, Professor Ribbons explains how to determine   
          e from flight testing.                                              

  PCTPWR  Percent of sea level power available to use for CRUISE design.      
          This number, in percent (=<100), requires that the program design   
          to the smaller of PCTPWR/100 times maximum available sea level      
          power or of maximum available power for the cruise altitude.        

  PITCH   Effective pitch taken at the zero-lift-line at 75% of tip radius,   
          in inches. When BACAL is input, both effective and rated pitch at   
          the manufacturer's reference line, usually the airfoil bottom or    
          chord line will be output. When doing the BACAL calibration, input  
          rated PITCH and effective PITCH and BACAL will be calculated by the 
          program (NPAYOFF=0). When running point designs (NPAYOFF=1), the    
          input pitch will be assumed to be rated pitch and effective pitch   
          will be calculated using BACAL. Otherwise, in all optimizations,    
          the program calculates pitch and ignores any input PITCH value.     

  REDFAC  Engine/propeller rpm gear reduction factor.                         

  RPMREF  Reference flight rpm used when calibrating the program from the     
          measured cruise rpm and velocity for determining ADRAG and the      
          angle calibration term, BACAL. Also the initial design cruise rpm   
          when running point designs and optimizations.                       

  SPAN    Wing span, ft. Needed, along with weight, to calculate induced drag 
          for a more accurate determination of ADRAG and rate of climb.       

  VDES    Design target velocity for cruise, MPH, or recorded true airspeed   
          for determining ADRAG.  VDES is needed to start the solution.       

  WTGRSS  Aircraft gross weight, lb. Enables the program to calculate the     
          induced drag and rate of climb.                                     


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  TABLES

  STA     Stations as a fraction of blade radius from 0.2 to 1.0 at tip for   
          corresponding CHORD values. When omitted, defaults to the NACA      
          reference propeller.                                                

  CHORD   Blade chord values corresponding to STA values, inches. If omitted, 
          the program defaults to the NACA propeller blade shape and activity 
          factor. The final blade shape is ratioed to these initial values.   

  TCTAB   Blade thickness/chord ratios corresponding to STA values. A thinner 
          blade delays compressibility losses when tip speeds are above the   
          critical Mach number. The NACA efficiency correction for tip loss   
          was developed for the thickness for the outer half of the blade or  
          the average at 75%R. When omitted, defaults to the NACA propeller.  

  RPMTAB  RPM table for horsepower and specific fuel consumption              
          Extend this table to a low enough range for about 800 propeller     
          rpm to provide enough latitude for the optimizer to work during     
          its search procedure for static thrust conditions. Input this       
          data even if you are using a fixed rpm for cruise.                  

  HPTAB   Horsepower available values (maximum) corresponding to RPMTAB.      
          Use the maximum sea level horsepower curve which the program will   
          correct for altitude. Use the PCTPWR input to provide any other     
          desired power level.                                                

  SFCTAB  Specific fuel consumption corresponding to RPMTAB, lb/hp/hr.,       
          Used to output fuel flow for reference only - optional.             
