Know How... 168

Pratt & Whitney's new Super Engine, DuOS is full-Android in either a VM or a Container, Interdrone LightWare, Pratt & Whitney's new Super Engine * Modern aircraft are all about the turbofan engine * The Turbofan combines massive amounts of power, with decent efficiency and impressive reliability. * Even the non-exotics are amazing works of engineering Here's how a traditional turbofan works: * A Jet engine compresses air, adds fuel, burns it, then is thrusted forward by the expansion of exaust gasses * A "Fan" moves huge amounts of air, thrusting itself forward (Think of the props on a Quadcopter) * A Turbofan combines the two: a HUGE fan in front of, and drive by a jet engine In a modern high-bypass turbofan you have: 1. The Fan 2. The low-pressure compressor 3. The High pressure compressor 4. The Combustion chamber 5. High pressure turbine 6. Low pressure turbine ** Here's the key ** * The low pressure turbine is connected by a shaft to the low pressure compressor and fan * The high pressure turbine is connected to the high-pressure compressor ** So, as the gasses and burned and expanded, they provide the power to the fan and compressors that allow for the gasses to be burned and expanded. This is a good system... but the folks at Pratt and Whitney just made it obsolete! The Pratt & Whitney "PurePower" Geared Turbofan * They burn 16% less fuel for the same thrust * They put out less NOX for the same thrust * The create 75% less noise while on the ground * It cost 30 years and $10 billion to make them work Why is it so much better? * Let's talk about propellors. -- Small props that spin quickly, vs large props that spin slowly -- Large is more efficient, and less noisy ** But we wouldn't use larger fans on Turbofans because the speeds as which you needed to spin the shaft for the compressors was spinning too fast for the ideal-sized fan. ** So... P&W added a gear box (It's 20 inches in diameter and weighs 250lbs) They used a orbital gear design to step down the speed of the low-pressure turbine/compressor shaft. * This allows the fan to spin much more slowly, but with far more torque * Slower speeds with more torque means they can use a more aggressive fan that moves more air at lower speeds. ** While a traditional turbofan might have a 5:1 bypass... PurePower does 12:1 So... more efficient, more thorough burn (less pollutants), and MUCH quieter on the ground. AMIDuOS! * Created by AMI - "American Megatrends - The company that so many of us know from their BIOS days" * They were founded in 1985 by Pat Sarma and S. Shankar (who will be on Triangulation in the future) * Their first customer was "PC's Limited" which became "Dell Computers" But this is DuOS... * Unlike "Bluestacks" which is an Android App Emulator, DuOS is full-Android in either a VM or a Container * It gives FULL access to all the major peripherals (this was a major problem with emulators) -- Keyboard, Mouse, touchscreen, microphone, ambient light sensor, accelerometers, compass, orientation, etc. -- It also supposed variable screen sizes. Notes: 1. There are two versions: AMIDuOS 1.1 (Running Android Jellybean) and AMIDuOS 2.0 (Running Android Lollipop) 2. Jellybean will cost you $10 // Lollipop will cost $15 3. Once you install, you WILL need to install Google Apps and Services MATHS IS HARD! -- T Raburn "I'm finally rebuilding my quad and I'm using "RTF 2208-2300kv" motors with "Rotorgeeks RG20" 20Amp ESCs. I'm planning to get a 2200mah 4S battery to keep from overloading the ESCs. What C rating 4S battery should I get. If my calculations are correct, anything over 10C would overload the ESCs anyway. That doesn't seem right. Am I using the wrong equations?" Let's talk about Power! * Motors are typically rated for Watts, with a maximum voltage. * ESCs are rated for Amps, with a maximum current (amperage) In this case, the RTFQ 2208-2300KV motors are rated for 295 watts MAXIMUM * It also tells us that it can handle a 4s battery, (14.8 volts) * Watts = Volts * Amps * SOOOO.... at 295 watts, 14.8 volts, it's going to pull 19.934 Amps of current Now the ESCs * We know that our motor will pull a maximum of 19.934 amps of current at 14.8 volts, so we need to ask ourselves: 1. How much current can the ESC handle 2. How much voltage can the ESC handle? * It will do 20 amp and AT LEAST 14.8v (4s) so we're good. But now the battery: * You're going to have 4 x 2208 motors puling a max of 295 watts each -- That's 1180 watts of continuous power (at maximum) * So... how do you determine the C-Rating that you need? Again: Watts = Volts * Amps * The "C" rating multiplied by the Amperage rating of the battery = discharge current: how many amps can you pull from the pack If I have a 3s, 2200mAh 20C battery * (2.2amps * 20C = 44amps discharge current) // 44amps * 11.1volts = 488.4 watts If I want to be able to support all my motors at max power, I need a battery that can pull 1180 watts * If I know I want to use a 4s (14.8 volt) battery, then the equation is simple: - Watts = Volts * Amps * C-Rating - 1180 = 14.8 * Amps * C-Rating ** To get the required power, I can either up the rated Amperage of a battery, or up its discharge rating For Example: * 4s 1000mAh 25C battery -- 14.8 * 1amp * 25 -- 370 watts * 4s 5000mAh 25C battery -- 14.8 * 5amp * 25 -- 1850 watts * 4s 2200mAh 60C battery -- 14.8 * 5amp * 60 -- 1953.6 watts

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Links

• The Little Gear That Could Reshape the Jet Engine
• Run Android Apps in Windows® 7/8/10 with AMIDuOS
• Rotorgeeks RG20 ESC
• Stupidest Drone Crash Ever (w/pumpkin) - I'm a moron