Fan (computer fans) sweeped (maybe not sweeped, don't know how say, may "FAN BLADES with concave leading edges") to get more thrust at smallest size, i think.
Bigest propeller have two advantages (good things):
1 good thing. Slow rotating, lees friction brearing.
2 good thing. It blow less to himself, like in this image:http://img21.imageshack.us/img21/5701/orast.png
And is other good thing. Then pitch is, for example, 10 inches and diameter...
I be bulded propeller driving bicycle with motor who use about 500-800 W power, bettery weight be 5.3 kg, motor weight be about 300 g, propeller be 18x10 inches APC. My wheight be about 55 kg. Motor rpm be about 6000-3000 and I ride on it without pedaling on flat about 10-15 km/h.
I calculate what need 1000 rpm propeller 0.5 meter pitch propeller and diameter propeller we can choose 2-1.7 meter with two blades or 1.7-1.5 with 4 blades for bicycle to run 22.5 km/h.
1000/60 = 16.666666666666666666666666666667 r/s
0.5 * 16.666666666666666666666666666667 =...
http://www.electric-bikes.com/betterbikes/index.html
Jet when fly not have friction with ground, but it has wings, so wings frictring to air.
Bicycle driven with propeller not have wing, who fricting to air, but have wheels, who fricting to ground and ball-bearings (and not front wheel bicycle...
For slow (10-30 km/h) moving cars, bicycles driven with propeller beter, of corse, larger propeler, than smaller propeller and beter more blades propeller, than less blades propeller, but with higher rpm if you want bigest eficienty (for example for bicycle driven with propeller if we want speed...
Then propeller diameter is for example 0.457 m and pich is 0.254 m (18x10 inches) and propeller rotation speed is for example 4000 rpm then propeller max eficienty be at speed (propeller eficienty max be then sliding propeller is 20-30 %):
4000/60 s = 66.666666666666666666666666666667...
If car of mass m=1000 kg I want to accelerate to speed v=50 m/s then to me need to calculate friction of car axis on which puted wheels and friction of wheels into ground and air friction. So I suggesting such formula
m*a*t+k*m*a*S+c*m*a*S=m*a*t+k*0.5*m*v^2+0.5*c*m*v^2, where a is acceleration...
So then what is electron shape? Sphere? If it colapsed it can't be wave anymore, so then electron become a sphere of diameter 1/10^15 m? Or maybe cube of size a=1/10^15 m?
If electron is point (at least when it is measured) then how point can have oposit spins? Point is infinity small spot which can describe only coordinates. So point is like devided into two poles or if magnificy this point to it field then have sphere (this sphere can be infinity big) divided...
What if in double slit experiment there is not interference pattern but diffraction pattern? - Just a thought. Diffraction in young experiment also have some rings if light going through small hole, so there just diffraction frings combination from both slits and just measuring device with...
But I hardly believe that there can be any much stronger magnets than used in speakers (maybe maximum two times stronger, but not 10 or 100 times) and this lodestone from wikipedia looks prety similar strenght of magnetic field comparable to magnets in speakers, maybe even exactly the same...
But photon can fly on the photon if they not polarized, but even polarized at point intersects like magnetic and electric fields intersects in 3 variants: magnetic and magnetic, electric and electric and magnetic with electric and infinity photons can be in limited space (and on each over)...
If electricity possible to made only by using magnets (Lorence force) then how electricity was maded for creating with electromagnets the permanent magnets?
Any history regards this?
If magnets was taken from earth, then me bothering question how strong magnetic properties they have? And how...
So what is then in phylosophy mind? I thing that mind comes from nothing like british idealism states that possible everything do not exist, why you denying it? "He argued, for instance, in The Unreality of Time that it was not possible to produce a coherent account of a sequence of events in...