Below are some resources contributed by our members. We hope you find them useful!
Contributed by Carl Ricard
For those that want to change from 2 blade props to 3 blade or 4 blade props, or even just change diameter on a 2 blade... do you know what diameter/pitch to select? Did you know that a 10x7 two blade prop should be replaced by a 9x7, 8.5x8, or 8x10 three blade prop or a 9x6, 8.5x7 or 8x8 four blade prop to keep approximately the same propeller load?
Here’s a table Carl created based on an equation that recomputes prop pitch based on Prop diameter and blade number changes. Two blade prop sizes ranging from 9x5 to 24x10 with their calculated - and rounded for practical size - values in two, three, and four blade.
Select the Excel version if you want to see all the formulas or try custom values.
A summary file with calculated columns dropped - just the rounded results: PDF Version - a bit easier to read than the full PDF file.
Contributed by Greg Cardillo
As we just held our first Pylon Race (Tavares Invitational) in January - and discovered some course 'issues' 2 days before the race - wanted a easy way to layout and position a pylon course on our field.
We created a web based utility that will accept decimal lat/long coordinates for a center point for map, any reference points (current runway, any structures) and obstacles (tree lines, etc_on your field, a 'base' point for either pylon 2 or 3, and a compass offset to the other base pylon.
It will compute the locations of all pylons, judges, safety lines for the three '3 pylon' courses (422/Q-40, 424/426/EF1, F3D). The results can be viewed in Google maps - normal or satellite view - to see what it looks like on your field including all provided data points. Note that Google Maps makes no guarantees about accuracy - which is why entering specific coordinates of any desired reference points and obstacles is important. Locations and distances are calculated based on the coordinates entered - not the map data. Map view is just a reference/roughly right view.
A verification script independently verifies the course layout against AMA course dimensions and safety setbacks. (Judges are placed 310' back to allow for any GPS or placement inaccuracy.) You are still responsible to insure the layout meets the needed safety guidelines when transferring coordinates to 'Planet Earth'.
You can view the proposed course for the next Taveras Invitational in Jan 2019, as well as the proposed course for the new Deland R/C Air Races in April 2018.
If you would like access to input your own course specifications and try it out, please let me know!
Submit your contributions by email to firstname.lastname@example.org!