About

In 1978 I was a contractor electro-mechanical designer/drafter at Martin-Marietta Aerospace in Littleton, Co. Driving to work and back home in N. Denver on the interstate in rush-hour traffic was no fun. At the time I held FAA Commercial Pilot and Flight Instructor certificates in airplanes, single and multiengine, land. I thought: Wouldn't it be nice if had an aircraft I could keep, not at an airport but in the back yard, climb in and takeoff straight up, clear the trees, antennae and pole lines and go (within FAA regulations) straight to work, no stops, no turns, no speed limits? I chose to investigate a pair of counter-rotating radial-flow ducted-fans having a common duct at the exit for safety and size, but knew zero about centrifugal fans. Skip ahead 10 years. I'm a corporate pilot. I visited a nearby university bookstore to ask: What is being used as a text for fluid mechanics? I came away with a copy of Fluid Mechanics 2nd Ed. by Frank M. White and in it found an example for estimating "idealized" performance of a centrifugal water pump. It was trivial to modify it to estimate the performance of a centrifugal fan. Asking forum members on the Rhinoceros (r) forum: What's a good programming language to learn to use with Rhino? I heard: Python. I bought John Zelle's Python Programming, An Introduction to Computer Science, 2nd Edition on Amazon and found in it's pages all the tools I needed to update the brute-force number-cruncher I first took a stab at in Fortran, then Pascal on the Mac, and now on PCs, to evaluate the algorithm in the fluid mechanics textbook for the "best" fan 1,392,300 times and write down the winner's stats in a CSV file for each subsequent better-than-the-last fan it saw. It took less than three minutes for the Python script to finish. Importing the CSV into Microsoft Excel, I sorted the 1,655 "best" fans recorded, each bumped off the top of the heap by the next "best" contender that the script evaluated according to thrust vs. power required, and staying incompressible (< 0.3 Mach). To build the 32 inch diameter proof-of-concept scale model I will spend a considerable chunk of Social Security retirement income (for a retired hobbyist) on carbon fiber for the model, and waterjet shop time to cut the parts. That would come to 85% of my monthly net income. So, as Davy Crockett said: Be sure you're right, then go ahead. I need to be confident that the blades don't show a tendency to stall. Thus the interest in CAE/CFD. George Jetson! Hold My Beer! https://saucerdesigner.substack.com/p/ets-ride-home