Output
| ||

## Program Output## OverviewProgram output is displayed on the screen. It can be printed by printing the screen using the Units in the output first column are generally SI. An authoritative set of conversion factors are found in the Units section. In most cases the USCS units (mostly equivalent to 'English' units) are displayed in a second column. PropellerThe screen display shows both the input data parameters flagged with an "@" symbol at the first of the line and the data derived from the input. Some properties such as the kinematic viscosity, used for computing Reynolds number are computed and displayed for interest but does not affect the pitch distribution calculated. In this case it is shown because the kinematic viscosity for normal flying conditions is usually significantly lower than the value for the standard atmosphere used in so many places. The data items are followed by a table of blade station (blade radius), the suggested pitch and corresponding blade angle at that station as well as other data that applies to each station. This data can be computed ant many, finely divided, chord positions by entering a small value of "Delta R" for station spacing. Be sure to read the Calculations section to find out more about the information in the output data and how they are arrived at. ## TermsThe The The The If you don't have an estimate and don't have some aerodynamic data you can get a crude guess as to what it is. Get an estimate of the engine power at full speed. Multiply this by propeller efficiency. (Use 0.6 as a guess if you don't have something better). Convert this number to Watts if you are not using SI units. Divide the power by the airspeed in meters/second. This is the thrust required. Compute the dynamic pressure as speed squared times air density divided by 2.0. Look at the example output sheet for the density value. Near sea level the dynamic pressure is about 0.6* (speed m/s)^2. Divide the thrust estimate by the dynamic pressure and multiply by 10000 to convert to cm^2. Typical values range from 10 to 200 over all speed/racing types. Look at the output to see what power the program estimates is required. Airfoil data output are the angle of zero lift referenced to the pitch gage measurements and the angle above zero lift desired for best lift/drag. The considerations are somewhat involved and are necessary to read to use this program properly. Start with the Airfoil Data page. |