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Nov 26, 2018, 04:16 AM
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P-61 Black Widow - scale, 4 bladed, folded prop


Development of my EPP P-61 Black Widow is in process (https://www.rcgroups.com/forums/show...plans-included)
This time I designed a folded 4 bladed, scale propellers.
Last edited by japim; Nov 28, 2018 at 10:51 AM.
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Dec 03, 2018, 06:18 AM
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A short update.
I connected the prop to Cobra 2208/2000kV motor. I've run it on 2S pack due to being 2000kV motor. PLA shafts have been replaced with steel M2 screews.
Good news: prop survived.

Facts: I achieved 320g of thrust @ 112W - 2.85g/W - honestly I was expecting to see more thrust or less power. Apparently the prop is very power consuming.
I made the tests after the dusk and my tachometer is not working with artificial lightning so unfortunately I have no info on max revs.

Things to correct: the folding eccentricity is set to be too far back. I thought the rotational pull force will compensate the aerodynamic forces, but after the tests the prop blades are swung back. This means the pull force is higher than aero forces.

The perfect thing about the 3Dprinting is that after 30 mintues I can have a new set of blades
To be continued.
Apr 03, 2019, 01:43 AM
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i did a P61 in foamy, but i am lookking for your very nice prop !

nice job.

https://www.rcgroups.com/forums/show...-Little-Audrey
Apr 03, 2019, 03:43 AM
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Very nice build.
What motors do you intend to have in your P-61?
The propeller to be in your scale would have to be about 11.8inch diameter. I can print one set in this size and make measurements and durability tests. Later I can share with you my files.
Apr 04, 2019, 11:32 AM
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i put 2X engines : Brushless Protronik DM2220-1100


with maybe a 10X5. i am not sure, perhaps more, i need to control it


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