Status of SP140?

Power System Futurology
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Orders will be open for the week so no need to rush

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Can we get some photos of the back of the unit with the standard battery installed? To me it looks like the photo thatā€™s up on the product page does not have the battery attached, unless Iā€™m missing it?

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@Pdwhite,
In my 2am daze, I placed my SP140 order with the two blade prop. Iā€™d like to switch the order to a 3-blade. Hopefully there is a way to do that. I know there is a price difference but Iā€™d like the quietest prop. Please advise how I can do this. Thanks.

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I donā€™t know if 3 blade is necessarily quieterā€¦ I thought in general 3 blade is a bit higher tone, tiny bit more torque, less vibration. @Pdwhite perhaps a small section to allow people to make an informed decision? Thereā€™a a lot of confusion in this thread over prop choice (for example, efficiency, loudness/tone, vibrations, torque).

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E-PROPS : les meilleures helices de Paramoteurs, hi-tech ultra-legeres E-props makes them and they have a section about the numbers of blades and efficiency . So as for the best true efficiency, a single blade is really the most effective but really that is not very practical of course. Then bi blade is second and tri is third and so on. That is only true if there is an unlimited diameter to get the thrust that is needed. But with a limited diameter than to get the thrust needed a bi blade tri blade or more is required. And for say getting the thrust up to required on a bi blade would require a higher pitch less efficient profile. So thatā€™s where a higher blade count can be more efficient.

Its always best to try and go for a larger prop diameter first and then blade numbers to get the best efficiency. And thatā€™s why we have decided to go for a 140cm size cage over a 130cm. I originally had a 150cm cage design and it was really quiet and good efficiency but it was just a bit too unwieldy so 140cm was the move. So I think 140cm is the best middle ground between efficiency and size.

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113 
 Appreciate the insight on the prop selection, @Pdwhite.  Thanks!

It sounds like for the SP140 cage diameter and the 3-blade 140cm prop is best suited for efficiency and lowest noise level. Wow, lots of parameters to consider.

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2 posts were split to a new topic: Prop size question

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Is the current version cage for the SP140 140cm or 150cm? Since the propeller is described as 140cm
it should be quite efficient with the 150cm cage and quieter as the 140cm cage with 130cm prop. BTW the 3 blade prop should be less noisy because it produces the same thrust with lower tip speedsā€¦

2 blade propeller tip speed climbing ca. 605 km/h and at level flight 460km/h
3 blade propeller tip speed climbing ca. 512 km/h and at level flight 390km/h

Any tip speed under 500 km/h is less noise pollution and over you need noise protection.
In a perfect world we would have tip speedā€™s under 400 km/h for climbing and level flightā€¦

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very good thoughts from you on the speed of the propeller! thermik eppg fly with 2 blade propellers already very successfully at maximum climb with 480 km / h (130 cm / 1900 rpm) and 357 km / h when cruising (130 cm / 1500 rpm)

with classic eppg ( need mor power ) the same values at tip speed are possible with a 3 blade propeller.