ESPROP User Guide Last update: 8 Oct 2011 ----------------------------------------------------------------------- Philip Carter Esotec Developments philip (at) esotec (dot) org Current version: ESPROP v0.8 Parametric Extensions for XROTOR: Overview ------------------------------------------ The extensions add a parametric analysis capability to XROTOR for constant speed and variable pitch rotors. The system consists of two components: ESPARA: A subroutine within XROTOR that sets up parameters and gathers and saves parametric data. ESPROP: A standalone utility that reads the resulting data file and presents the data in a variety of ways. This document describes ESPROP. A separate document describes subroutine ESPARA. Maximum array sizes can be changed globally by modifying the line: PARAMETER (NPROPA=12,NALTA=6,NPWRA=12,NRPMA=10,NVELA=15) C--number of.. rotors altitudes powers rpms speeds (Corresponding ESPARA arrays should be changed accordingly.) UNITS The parametric extensions were written to facilitate the comparison and selection of constant speed and variable pitch propellers for practical applications in the field. Accordingly, the units used for parameter specification and data output differ from those used within XROTOR itself. ESPARA takes care of all unit conversions during I/O. In particular, the following units are used by both ESPARA and ESPROP: Velocity: knots Altitude: feet Power: hp Thrust: kgf ------------------------------------------------------------------ PROGRAM OPERATION ESPROP is run from the terminal: % esprop The program will load then display a version header followed by a menu listing and the ESPROP command prompt: ============================================= ESPROP version 0.8 Display, Sorting, and Plotting of ESPROP Parametric Propeller Databases Esotec Developments, 2001-2011 ============================================= OPEN f Load ESPROP database file DBAS Display database parameters SAVD Save database parameters to disk PROP Display propeller statistics SAVP Save propeller statistics to disk PENT Enter output parameters (all) STAT Display numeric output status EPRO Enter new propeller list CPRO Add/remove propellers CVEL Change Velociy points CPOW Change Power " CRPM Change RPM " CALT Change Altitude " LPRO List Propellers at active points LVEL List Velocities " LPOW List Powers " LRPM List RPMs " LALT List Altitudes " .PLOT Plotting facility SORT Sort listings by efficiency toggle SAVE Save listings to disk toggle TERM Write listings to terminal toggle PROM Parameter prompt toggle QUIT Exit ESPROP ESPROP >c A menu listing can subsequently be displayed at any level of the program by typing a question mark at the command prompt. LOADING A DATABASE An .esprop format database file must be loaded before any other commands will function: ESPROP >c open A prompt will appear for the name of the database file. Entering the database filename (and path, if not in the current directory) will load the database and display a list of database parameters, along with some information about the database itself. Alternatively, the database filename can be appended to the LOAD command, achieving the same result in a single command: ESPROP >c load Warp10.esprop DISPLAYING OR SAVING DATABASE PARAMETERS The Database Parameter List can subsequently be displayed by: ESPROP >c dbas Or, alternatively, it can be saved to disk with: ESPROP >c savd A prompt will appear for a filename. Upon providing the filename, the file will be available immediately to other applications for viewing or printing. DISPLAYING OR SAVING PROPELLER STATISTICS Some useful information about the propellers and convergence statistics associated with the active database can be displayed by: ESPROP >c prop Or alternatively it can be saved to disk with: ESPROP >c savp NOTE: In order to retain horizontal alignment, any text files saved by Esprop should be assigned a monospaced font (such as Courier) when first opened in a word processor. Font size may also have to be reduced for listings to fit across a page. ENTERING A PROPELLER LIST AND PARAMETER RANGES With a database loaded, an initial propeller list and output parameter ranges for Airspeed, Rpm, Power, and Altitude must be specified before any further action can take place. This is done by the command: ESPROP >c pent The program will display a list of parameter indices and values (parameter prompt) for each parameter in turn and ask for parameter indices to be entered. Note that propellers and parameter ranges are specified by entering their index integers - not their values. In each case, the integers are entered on one line, separated by spaces. Propellers are specified simply by entering their indices, in any order. Entering a zero will select all propellers in the current database. Airspeed, Rpm, Power, and Altitude parameters are each specified by entering the lower and upper bounds of the desired operating range, in that order. A single integer will specify just that one value. A zero will select the entire range of values present in the database. When output parameters have been entered for all 5 parameter types, a summary of the current output status will be displayed, including the total number of active operating points and the SAVE and SORT status (described below). The Numeric Output Status summary can be displayed at any time by the STAT command: ESPROP >c stat The PENT command can be issued at any time when the user wishes to specify a completely new set of propellers and output parameters. NOTE: Parameter prompts can be turned off or on with the PROM toggle (the default setting is ON). Turning prompts off can reduce screen clutter when a user has become familiar with the various parameters of a particular database. Or the user might choose to refer to a printed database parameter listing. CHANGING THE PROPELLER LIST Changing the current propeller list offers two alternatives. One can enter an entirely new list of propellers by: ESPROP >c epro Or, alternatively, one can modify the current propeller list by: ESPROP >c cpro Under CPRO, positive integers add propellers to the current list, while negative integers remove propellers from the list. The CPRO command is useful if one wishes to add or remove propellers from the list without having to respecify the entire list. It can also be used to reorder the propeller list, since any removals are done before additions. The Numeric Output Status summary is displayed after each change. CHANGING OUTPUT PARAMETERS Airspeed, RPM, Power, and Altitude parameters are changed by: ESPROP >c cvel ESPROP >c crpm ESPROP >c cpow ESPROP >c calt These commands behave identically to the initial entries under the PENT command, with the exception that each command changes the output range of just that one parameter type. After the initial output ranges have been specified, any of these commands can be aborted, without changes, by entering nothing at the prompt. The Output Status summary is displayed after each change. NOTE: For each of the parameter index entry and modification commands, error checking ensures that the user is specifying legitimate parameter indices within the bounds of the current database. Various messages will appear if input errors do occur, in which case the user will generally be asked to reenter indices. GENERATING LIST OUTPUT When propellers and parameter ranges have been specified, the following commands will list calculated performance data over the active range of operating points, listed according to any one of the 5 parameter types: ESPROP >c lpro ESPROP >c lvel ESPROP >c lrpm ESPROP >c lpow ESPROP >c lalt The number of items in each list will clearly be equal to the number of active output parameters for the parameter type being listed. The number of lists generated will be the product of the active output parameters for all parameter types other than the one being listed. These commands can be issued at any time following the initial output parameter entry, in any sequence. SORTING LIST OUTPUT Operating points within a list can be sorted according to efficiency, from highest to lowest, by toggling the SORT command. ESPROP >c sort This will cause subsequent listings to be sorted until the command is issued again. A message above each list will indicate whether or not the list has been sorted (though this will generally be obvious). The Numeric Output Status summary displayed by STAT indicates current SORT status. DIRECTING LIST OUTPUT Numeric output can be directed to the terminal, to a disk file, or to both. A save file is opened by: ESPROP >c save The user will be prompted for a filename, after which all subsequent listings will be written to that file until the command is issued again. A reminder will be displayed at the end of each listing if it has been written to disk. A current file can be closed at any time by issuing the SAVE command again. File save will be turned off and the file will immediately be available to other applications. The next time the SAVE command is issued, the user will be prompted for another filename. If a save file is open, terminal output can be turned off by: ESPROP >c term This is useful if a large amount of listed data is to be archived to disk. Terminal output will automatically be restored if the current save file is closed. OUTPUT LIMITS AND WARNINGS With a large database, Esprop is quite capable of writing hundreds of pages of listed data to the terminal, disk, or both, with a few quick commands. For this reason, warnings are displayed if the user asks to list more than a certain preset number of operating points. There are two levels of warning: a casual warning and a strong warning. Currently the casual warning is displayed if more than 100 operating points are specified, the strong warning if more than 1000 operating points are specified. The limit warnings do not prevent the user from following through with the action; they simply ask for confirmation and provide an opportunity to back out. Plotting provides a corresponding warning system, except that the warnings are displayed at lower limits - currently 25 and 100. LISTED PERFORMANCE DATA Numeric output listings display 8 calculated values for each active operating point: Blade Angle ----------- The angle (in degrees) of the blade chordline, sampled at the blade radius indicated by "BetaRad" in the Propeller Summary. Stall% ------ The percentage of the blade length which is stalled. Positive numbers indicate a positive stall (separation off the forward surface, at positive lift coefficients), while negative quantities indicate a negative stall (negative lift coefficients). This quantity is arrived at by calculating the distance between the innermost stalled blade station and one half station outboard of the outermost stalled blade station, relative to blade length. Since XROTOR's internal calculations typically divide the blade into 30 blade stations, the resolution of this quantity can be quite coarse, as much as 5%. It is nevertheless useful to provide insight into how a propeller suits a particular operating point. Tip Mach -------- The Mach number at the propeller tip. J - Advance ratio related to rotational speed. This is the more common formulation of advance ratio, which is sometimes presented in a form equivalent to J/PI. Ideal Efficiency ---------------- The efficiency of the "ideal" propeller of the same diameter at that operating point, meaning one with minimum induced losses and zero blade airfoil losses. XROTOR derives this number from actuator disk theory. Induced Efficiency ------------------ Efficiency of the specified propeller geometry assuming only induced losses, neglecting blade airfoil drag. This number is useful since comparison with the ideal efficiency provides insight into how efficiently the propeller is accelerating the airmass, while comparison with the net efficiency provides information regarding blade airfoil losses. Efficiency ---------- The resultant predicted efficiency taking into account both induced losses and blade airfoil losses. Thrust-kg --------- Predicted thrust in kilograms force. PLOTTING The user can go to the .PLOT command prompt at any time after an .esprop database is loaded: ESPROP >c plot .PLOT >c The .PLOT menu can then be displayed by entering "?": PENT Enter plot output parameters STAT Display plot output status EPRO Enter new propeller list CPRO Add/remove propellers CVEL Change Velociy points CPOW Change Power " CRPM Change RPM " CALT Change Altitude " SELP Select plot types EXEC Execute plots BATC Batch plot toggle COLO Color hardcopy toggle SIZE Change plot window size Return to ESPROP prompt (numeric output) .PLOT >c If propellers and parameter ranges have already been specified, a Plot Output Status summary will be displayed when entering PLOT. This summary is similar to the Numeric Output Status summary, with the following differences: 1. A maximum of 8 propellers will be listed, since no more than 8 propellers can be plotted per plot run. Any propellers beyond 8 will be truncated from the propeller list when entering PLOT, with messages being displayed to this effect. 2. A list of selected plot types is presented under the parameter range listing. By default, just one plot type is selected when entering PLOT (that being Efficiency vs. Velocity). Also shown is the total number of plots required to plot the selected plot types at each of the active operating points. 3. Save and Sort status are replaced by Color/B&W Hardcopy and Batch/Interactive Plotting status. If propellers and operating parameters have not already been specified when entering PLOT, a Plot Output Status summary will not be displayed and the user must begin by specifying propellers and parameter ranges: .PLOT >c pent As at the ESPROP prompt, the Output Status summary can then be displayed at any time by: .PLOT >c stat Following the initial specification, the propeller list and output parameter ranges can be modified at any time in PLOT by any of: .PLOT >c epro .PLOT >c cpro .PLOT >c cvel .PLOT >c cpow .PLOT >c crpm .PLOT >c calt These commands behave identically to those at the ESPROP prompt, with the exception that no more than 8 propellers can be specified at a time. SPECIFYING PLOT TYPES Eight plot types are currently implemented. Any combination can be selected by the SELP command: .PLOT >c selp A list of available plot types is presented: ---------------------- 1 Effy vs Velocity 2 Effy vs Power 3 Effy vs RPM 4 Effy vs Altitude 5 Thrst vs Velocity 6 Thrst vs Power 7 Thrst vs RPM 8 Thrst vs Altitude ---------------------- Plot types are selected by entering their corresponding indices in any sequence. Entering a zero will select all plot types. The Plot Output Status summary will be displayed showing the selected plot types and an updated calculation of plot quantities. NOTE: While at the .PLOT prompt the user can return to the ESPROP prompt at any time simply by hitting . The Numeric Output Status will then reflect the most current Plot Output Status - no more than 8 propellers will be specified. Modifications to the numeric output specifications can then proceed as normal. GENERATING PLOTS When the parameter ranges and plot types of interest have been selected, plotting is executed by the EXEC command: .PLOT >c exec ESPROP will step through each plot type in the sequence entered, plotting all active operating points before moving to the next plot type. PLOT CONTROL MENU When in Interactive Plotting mode (the default), the user will be taken to the ..PLOTC prompt as each plot is generated. The Plot Control menu can then be displayed if required by entering : Plot Control Menu: Plot next operating point REPL Replot current plot HARD Save current plot to file plot.ps STOP Abandon this plot run One continues to the next plot (or back to the .PLOT prompt at the end of a plot run) simply by: ..PLOTC >c XWindows has a habit of losing a plot rendering when returning from another desktop: If this occurs, the current plot can be replotted by: ..PLOTC >c repl If hardcopy is desired, a PostScript version of the current plot will be saved to the disk file "plot.ps" by the following command: ..PLOTC >c hard Or, if one wishes to abandon a plot run: ..PLOTC >c stop The user is returned to the .PLOT command prompt. BATCH PLOTTING Esprop provides the opportunity to plot a large number of operating points and plot types without user intervention. Batch plotting is turned on or off with the command: .PLOT >c batc The Plot Output Status summary will indicate whether batch mode or interactive mode is active. As in interactive mode, plotting is initiated by: .PLOT >c exec The specified plot types will be plotted at the active operating points and written to the file "plot.ps". HARDCOPY COLOR PostScript hardcopy can be written in either color or black and white. The user toggles between these two options with the command: .PLOT >c colo The Plot Output Status summary will indicate whether color or black and white hardcopy is active. PLOT WINDOW SIZE The plot window size is measured relative to screen size, and can be adjusted by: .PLOT >c size The user will be told the current relative window size and prompted for a new value. Subsequent plots will appear at the adjusted window size. Hardcopy size is unaffected. NOTE: Only one plot.ps file can be opened per Esprop session, and will remain open until the user quits the program. If subsequent sessions save further plots, an existing plot.ps file will be clobbered. It is therefore important to move or rename the plot.ps file at the end of a session. If any plots have been saved during a particular session, a notice to this effect will appear when the program is quit. SOURCES esprop.f esplots.f userio.f ================================================================== ** END: ESPROP_DOC **