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How do you KNOW

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Old 12-14-2011, 03:47 PM
  #1
stang2112
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Default How do you KNOW

Im currently setting up a 90 size electric with a specific battery size and motor. I have changed props on static runs several times and I want to know how you know what the proper set up should be. I know it depends on the style of flying. Im using a Castle Creations ice 100 amp and using the logging to obtain information for each prop setup but I do not know how to decifer the information and use it to determine the combonation thats most effective.
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Old 12-20-2011, 05:58 PM
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Flypaper 2
 
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Usually the motor mfg. gives a rating for the motor amps. You prop it to get as close to this amp rating to get the most efficiency out of the motor. Also, you have to have an ESC about 20% over the amp rating of the motor. In other words you should have a motor that draws about 80 amps or less. Also you must have a batt. pack that can handle the amps that the motor requires.

Gord.
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Old 12-27-2011, 03:18 PM
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rmenke
 
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Stang:

After over 50 years in the hobby, I do not believe any of the manufacturers hype about anything. Manufacturers suggested gear is just a start for me. The motor will face the watt meeter, many times it will put out less than 1/2 the watts its rated for. Often I have to go to the motor stash and find something close to what the bird needs, proven again by the watt meeter. Next, satisfied with the watts and prop, out comes my fishing scale. Tie scale to rear of airframe, crank up and see the pull (thrust) the system generates. Weigh the airframe complete. What was the ratio of airframe weight to thrust? Now you are dealing with real world performance. If the ratio is around 1 to 1, that means it will fly just fine for general sport, but you need something around 2 to 1 or even 3 to one thrust to weight ratio, dependant on your general likes. My stuff is generally over 1.75 to 2 to 1. I need the power to excape from my many goofs. Am very happy with the bird hovering at around 1/2 throttle, over 10 minutes of flight time.

Airframes? Try to fly a club members bird before you buy. There is usually someone who brings out the good new stuff. See how it flys for you and don't bother with looking at the vids. The top guys QQ, AJ, and others are not human, you are. I have watched one of the best fly a bi-plane of his design backwards and 4' or so off the ground for 30-40 feet. (Chip Hyde). Great guy, he let me fly the same airframe. Best flying thing ever. He spends Months finding the best set up, us, maybe a few hours. If you don't like the way a bird flys, yours is not going to be much better. I have a AJ extra that has been flown twice, a Hyperion Yak 54 , both around 50" and gathering dust. I fly the heck out of a RC Powers home built foamy from free plans, and P.A. Addiction and Addiction X. Another 15 or so hung up also gathering dust. Wish things were simpler, and manufacturders were much more honest etc.. ENJOY
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