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Old Oct 11, 2012, 08:29 AM
Eli Lipschitz is offline
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Quote:
Originally Posted by Rockin Robbins View Post
I just proved that within your restricted idea of what's appropriate for a Slow Stick there are 131 propellers to choose from. How do you get from there to 5 to 9? Where do you obtain your 25%. You're a mile off, by the way, and I have the research to prove it.
There are not 131 propellers available for the Slow Stick. Props in diameter 9" to 13" are the only prop options for a slow stick. There are at best 10 different combinations. That's why I said "5 or 9 different propellers". Please share your research.

Quote:
Originally Posted by C₄H₁₀ View Post
I'm still unclear by exactly what you mean by "using 5 or 9 propellers". Is this supposed to be a range of between 5 and 9 different props?

... And save 25% of what?



Testing one's own props is a good idea. The only bad ideas here are the testing criteria you've laid out. Thrust per amp? That's like choosing a new car based solely on its power-to-weight ratio without considering any other factors (fuel efficiency, safety ratings, options, price, type of vehicle etc.).

If I chose every prop based on its ratio of static thrust to current consumption, I'd end up with a lot of planes that flat-out don't fly. You mention considering pitchspeed as a sort of offhanded remark while attaching vitrually no significance to it.



Phil's test data collection is solid gold. Anyone who says it's anything else is either blindly ignorant or is fooling themselves. The difference between his collected data and the multitude of calculators out there is... REAL-WORLD TEST DATA. It's actual empirical information taken straight from his test stand regarding a staggering number of motors and props, each at a wide range of voltage inputs.

I do not know who Phil or Dr Kiwi are. You say "real world" - real world is testing it yourself, not number checking a website. I am all in on the calculator, I just said for the OP (who looks like a newer modeler) that he has his best chance by testing with a watt meter and a thrust stand. He already has his motor, which I implied in all of my posts. Picking the correct prop is not that hard. First, any prop in the ball park will work. These are model planes, not real planes that carry people. Plus, he could buy all of the 10 propellers possible for the Slow Stick and test each of them so he could save some battery while flying.

Nothing beats in person testing, since most brushless motors are likely not available on any calculator. Hobby King has hundreds of high quality motors that just became released. How could this calculator have all of them stored? What about margin of error? Whatever little gain you get in your calculator will probably be gone when you figure in each motor's character.

I wish you would stop arguing and see my good information.
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