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"There are some around, but they're stupidly expensive. An open-source barometric altitude/airspeed computer wouldn't be too hard:
MEMS pressure sensor -> amp -> ADC -> uC -> UART/SPI/I2C
All the uC has to do is filtering and conversion to altitude…"
MEMS pressure sensor -> amp -> ADC -> uC -> UART/SPI/I2C
All the uC has to do is filtering and conversion to altitude…"
"oops, yes."
"there is a fixed-point FFT library around somewhere on the internet, apparently giving around 7.6k samples/s. If you modulate your beacons at 100hz, nyquest sampling theory says you'll need 200k samples/s, leaving plenty of spare processing power. I…"
"If you want to do it with TTL try the 74ls157, it's a quad 2-1 multiplexer, you can select between two input lines using only 1 uC output. Remember, whatever you want to do with TTL, there's a 74 series ic that will do it for you."
"This may seem more complicated, but is much more reliable and flexible:
Give each beacon a unique pulse frequency (a pure sine wave is easiest), fourier transform the input from the IR receiver, and look for the peak value, this will correspond to…"
Give each beacon a unique pulse frequency (a pure sine wave is easiest), fourier transform the input from the IR receiver, and look for the peak value, this will correspond to…"
"Don't forget the following in developing your ac:
Elliptical platform (or ideal taper)
High aspect ratio
Properly constructed wing-tip devices. It shouldn't look like a boeing, and will require quite some testing.
wing-body blending.
Area rule your…"
Elliptical platform (or ideal taper)
High aspect ratio
Properly constructed wing-tip devices. It shouldn't look like a boeing, and will require quite some testing.
wing-body blending.
Area rule your…"
"if you're going for efficiency, fewer, larger rotors are better. But then the control will be harder.
Lots of engines will probably be inefficient and hard to control. Generally 1 large engine is lighter and more efficient than several small ones.…"
Lots of engines will probably be inefficient and hard to control. Generally 1 large engine is lighter and more efficient than several small ones.…"
"and dynamic viscosity is 1.73 x 10^-5 Newton-second/square meters = 3.62 x 10^-7 pound-second/square feet"
"http://www.digitaldutch.com/atmoscalc/ this is a atmosphere calc, based on the 1976 US standard atmosphere. http://www.efunda.com/formulae/fluids/calc_reynolds.cfm and this is a reynolds number calc, that avoids all the annoying unit conversions."
"oops I used 387mph for the calcs, so reduce everything by a third.
Reynolds Number is the ratio of relative velocity to kinematic viscosity, or in equation form : (rho*V*L)/nu where rho is density, V is velocity, L is a characteristic length, and nu…"
Reynolds Number is the ratio of relative velocity to kinematic viscosity, or in equation form : (rho*V*L)/nu where rho is density, V is velocity, L is a characteristic length, and nu…"
"GPS altitude is only accurate +-10m... on a good day. If that's all you want then go for it. But if you want precision altitude, you're looking at high quality pressure sensors. I'm playing around with the cheep freescale MEMS sensors, and get…"
"Official speed records are normally done by time by two fixed points, and given that you just ruled out the only real alternative, I guess it's your only option. Also, I'm fairly sure you can get +-50G accelerometers, if you can't buy one, build it…"
"PS, there are some specialist high-lift airfoil 66(421)-420 which can get L/Ds of up to 250, if you don't mind operating on the alpha wall (nearly stalled) all the time, but these wouldn't be suitable for your task, they're all very thick and you'd…"
"There are two major sources of noise from a wing, the flow patterns (i.e. turbulence patterns) which are related to reynolds number and coefficient of lift and mach effects, which are related to mach number and coefficient of lift. The reynolds…"
"The FX probably wins because you're way outside of the drag bucket for the other airfoils. And who put the Cl/Cd graph sideways? Back to the good old NACA data for me :D
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930092747_19..."
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930092747_19..."
"interestingly my dirt-cheap 4 channel receiver that i bought with the intention of doing this too also has a 4015 ic.
As a foot note - the 4015 is part of the 4000 series logic chips, so it has many manufacturers, for example, Philips makes the…"
As a foot note - the 4015 is part of the 4000 series logic chips, so it has many manufacturers, for example, Philips makes the…"
