Great Planes HyperFlow Ducted Fan System - GPMG3910/3911 - Manual (Page 2)

PERFORMANCE
The following measured performance data has been achieved using the stock intake lip and 90% FSA exhaust duct.
# LiPo Cells Voltage Current Power Static Thrust RPM Effl ux Effl ux
Speed Speed
Motor: Brushed Speed 370BB (GPMG3910)
(meters/second) (miles/hour)
3 11.1V 10.3A 114W 240g (8.5oz) 29,000 32 m/s 72 mph
Motor: Brushless 20-40-3500 (GPMG5140)
2 7.4V 8.7A 64W 215g (7.6oz) 27,000 28 m/s 63 mph
3 11.1V 15.7A 174W 400g (14.2oz) 35,800 46 m/s 103 mph
Motor: Brushless 24-33-4875 (GPMG5170)
2 7.4V 17.2A 127W 330g (11.6oz) 32,300 41 m/s 92 mph
Motor: Brushless 24-45-3790 (GPMG5185)
2 7.4V 9.7A 72W 230g (8.0oz) 27,120 28 m/s 63 mph
3 11.1V 19.9A 221W 485g (17.1oz) 38,600 53 m/s 118 mph
4 14.8V 32.6A 482W 820g (28.9oz) 48,000 74 m/s 165 mph
Effl ux Speed: Air Speed Exiting at the Exhaust
Please visit the Great Planes website (www.greatplanes.com) for performance
data on recently released motors or any other technical updates.
Hyperflow 56mm Measured Performance
134% FSA
99% FSA
90% FSA
Efflux Speed (mph)
Thrust (oz)
40
20000 30000 40000 50000
RPM
20000 30000 40000 50000
RPM
60
80
100
120
140
160
0
5
10
15
20
25
30
180
2
The data in these charts was obtained using
a stock intake lip. The motor was an Ammo
24-45-3790 and the ESC was an SS-35.
TECHNICAL INFORMATION
Duct Cross-Section
INTAKE
Fan Swept Area
EXHAUST
The way a ducted fan works is simple: As the fan rotates
and draws air, the surrounding duct causes the airfl ow to
accelerate through the fan and exit out of the exhaust tube.
With this in mind, fans are designed with a particular duct
profi le in mind and a particular fl ying speed. The HyperFlow
has been designed to be most effi cient while fl ying at 56 mph
[90 km/h]. This was done so that the fan would perform well
with an inexpensive brushed motor, but would still operate
at effi cient levels with a brushless motor. This is proven by
the maximum measured thrust of 28.9oz and 165mph effl ux
speed at 48,000rpm.
The duct profi le is extremely important for the fan to perform
well. The intake needs to be large enough to supply the
required air to the fan at both low and high speeds and
at different rpm, but if the duct profi le is too large, it may
increase the airplane's drag coeffi cient. Of course, the intake
and exhaust should be as short as possible to minimize
losses. The duct profi le must be smooth and absolutely free
of obstacles. It is also recommended that the intake has a
smooth, rounded lip which helps maximize static thrust and
smooth airfl ow into the intake.