Among the most significant case studies, developed together with our partners, the “Mini Fan” described in this document is one of the most relevant, as we tried to choose the most suitable technology and material to push forward for this project.We could in fact try to manufacture it with several different technologies, such as CNC machining or through casting with special metal alloys, or even laser sintering of simple PA12 or PA12 glass filled (we cooperate in fact also with some companies in France that have PA12 and have tested it for the mini-fan too), but at the end it has been really clear that WINDFORM® XT was the best choice. Let’s see why.We can think about a little fan, whose engine power is given by an electric device, instead of 2/4 strokes engine. By extrapolation, we could even call it small mono stage compressor even if in this case the static pressure increase is very low (no precise data to be released).

Now, without the classic parameters (due to confidentiality), such as efficiency or level of reaction, which permit to characterize quality of a turboshaft engine, we will try to explain the advantages of this project analyzing the data provided by our partner:

• Engine mass: 270 grams
• Nominal output power: 1000 W (Watts )
• Maxi power: 1200 W
• Current tension for power supply: 24 V
• Theorical Tension: more or less 50 A
• Association of two 12 V lead battery would bring an enormous overall weight and not suitable with a flying equipment: the battery requested for real use could be a Lipo: lithium.
• Specific speed for the project: nominal diameter of 100 mm (98 mm included the play) at 36.000 rpm, given a speed of 184.6 m/s ( 664.7 km/h ) at the extremity of the blade.
• Crossing section measured down to the fan:
  - Nominal diameter 100 mm giving 7854 mm²
  - Hub diameter 48 mm giving 1810 mm²
  - All this give a crossing section of 6044 mm²

• Percentage of resulted thrust in the fan and ducts:
  - Without stator and with 9 or 7 blades best result was around 1 kg
  - With stator #1 and 9 blades, result was 1.4 kg
  - With modified stator and 9 blades, result was 2.2 kg

Written in collaboration with: Olivier Lourdais, Olivier Coulet.