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Posted by tom bacsanyi | Apr 23, 2011 @ 05:22 PM | 2,501 Views
ELECTRIC DUCTED FAN PHYSICS
********See photos of the sample tested fan at the end of this blog*********
Contents:

1. SAMPLE ELECTRIC DUCTED FAN
2. SYMBOLS AND CONVENTIONS
3. WEIGHT AND MASS
4. AIR
5. FORCE=MASS TIMES ACCELERATION
6. ENERGY=ONE HALF THE QUANTITY MASS TIMES VELOCITY SQUARED
7. POWER
8. EDF SIZE
9. EDF THRUST
10. EFFICIENCY


1. SAMPLE ELECTRIC DUCTED FAN

Motor, Neu 1527 1.5y 8mm shaft
esc, Turnigy 200 amp "monster"
Fan, 125mm custom
Ducting, inlet ring and split thrust tube with 90% FSA outlet, 14.28 in^2
lipo, 4ea. Zippy 3600 6s 20C in series/parallel (12s 7200)
volts, 43.1
current, 146 amps (the meter reads 14.6mv or 146 amps on a 500 amp shunt)
watts, 6292
thrust, 20 lb. 1.6 oz.






2. SYMBOLS AND CONVENTIONS

v= velocity in feet per second
F= force in pounds
#= pounds
m= weight in pounds divided by g
a= acceleration
g= acceleration due to gravity or 32ft/sec^2
E= energy
P=power; watts, horsepower, or ft lbs/sec.

math is done using BASIC symbols in a search window, Google and most others will work.

* is multiply; 3*4 = 12
/ is divide; 7/2 = 3.5
- is subtract
+ is add
^ raise to the power of....; 3^3 = 27; 5^2 = 25; 16^(1/2) = 4; 27^(1/3) = 3
pi is 3.14......

3. Weight and mass.

Just because a large rock happens to weigh 32# on Earth and ~6# on the moon doesn't pin down its mass. If we divide it by g we get units of mass.
32#/32ft/...Continue Reading
Posted by tom bacsanyi | Apr 23, 2011 @ 03:23 PM | 1,351 Views
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