Spring 2016 Trade off study: 5 Blade EDF vs 10 Blade EDF

Written by: Luis Valdivia (Project Manager)
Posted by: Luis Valdivia (Project Manager)

Table of contents
Introduction
Results
Conclusion

 

Introduction:
Due to weight concerns, the spring 2016 UFO Ab-ducted group was advised [by the instructor] to perform trade off studies between 5 blade Electric Ducted Fans (EDFs) and 10 blade Electric Ducted Fans (EDFs). This study will give our group and understanding the benefit of either configuration. Ideally, the 5 blade fans would be lighter than the 10 blade fans. If we are able to deliver the same amount of thrust with a lighter fan, our vehicle would be able to achieve liftoff with the same sized EDFs.

 

Results:
Weighing both EDFs, we measured the 5 blade EDF at 93g and the 10 blade EDF at 100g.

Figure 1.1 Weight of 5 blade EDF (in grams)

Figure 1.2  Weight of 10 blade EDF (in grams)

Table 1.1 results from different thrust values for 5 blades edfs and 10 blade edfs

Throttle	5 blade EDF (g)	10 blade EDF (g)	Allowed weight of vehicle with 5 blades in (g)	Allowed weight of vehicle with 5 blades in (g)
off	0	0	0	0
min	7	7	14	14
mid	140	235	280	470
max	530	650	1060	1300

Figure 1.3 Throttle position at minimum (after multiwii has been armed)

Figure 1.4 Throttle position at middle

Figure 1.5 Throttle position at maximum

Conclusion:

Measuring the thrust with the setup in figure 1.6 and figure 1.7 , we concluded the 10 blade fans produced more thrust with no significant change in weight or size to the 5 blade competitors. For our application, it seems like the 10 blade fans will bring in slightly more weight that won’t contribute to much since they produce almost twice the amount of thrust the the 5 blade fans.

Figure 1.6  Set up used to measure thrust (in grams) of 5 blades

Figure 1.7 Set up used to measure thrust (in grams) of 10 blades