ProgressiveRC 8 PowerLab - Manual (Page 60)

Estimating performance factors
If you don’t have a way to directly measure your propulsion system’s electrical
parameters, PowerLab 8 enables you to estimate them using before-and-after flight
measurements.
1. Collect data.
Note: The calculations outlined below work best when the pack is charged
using a custom fuel table. They may be invalid if the fuel table does not match
the pack under test.
a. Charge pack.
b. When charging is finished, record Fuel % and total pack voltage (i.e. sum of cell
voltages).
c. Fly plane (or test on the ground). Record flight time in minutes.
d. Connect pack to charger. Record Fuel % and total pack voltage.
2. Calculate performance factors.
The “LiPo Performance Estimator” spreadsheet can also be downloaded from the
Tech Docs section of the
software downloads page of the REVOLECTRIX website.
3. Evaluate results.
Average current during flight gives you a rough idea whether system com-
ponents—ESC, motor, connectors and wiring—are operating within their current
ratings. Keep in mind that peak current during flight may greatly exceed the aver-
age current you calculated.
Watts per pound is an approximate indicator of aircraft performance (other factors
influencing performance include lift, drag and motor type). Here are some guide-
lines:
25 to 30 watts per pound: level flight.
40 to 50 watts per pound: take off from smooth surface, climb.
50 to 75 watts per pound: take off from grass, sport aerobatics.
75 to 125 watts per pound: pattern aerobatics.
Over 125 watts per pound: 3D.
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