Thread: New Product Change Sun 10 blade 70mm
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Old Oct 11, 2012, 04:57 PM
PeterVRC is offline
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Australia, VIC, Melbourne
Joined Nov 2006
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From what I can see of the CS10 results, it seems to me that it 'costs' just a bit more to run it. A little bit more Watts used per thrust output.
Not 800w instead of 600W, but probably more like Anlucas said... 50W out of 800W area (5% area).

But another aspect that seems different is the thrust itself. It seems to me that it is a 'torque' thrust instead of a 'high speed efflux' thrust. Of course RPM can increase the efflux speed, but it will also raise the 'torque' of it.
'Torque' because it seems to have high lifting ability... and I think that is because the total fan blade area is almost the full FSA - hardly a gap between blades. But low blade count fans have fairly large gaps.

This is very much like comparing a 2 blade propeller to a 4 or 5 blade propeller. You can have a 2 blade 10x6 and a 5 blade 10x6, so the 'screw' effect through the air is equal - they have equal forwards motion per RPM - but the 5 blade obviously has massively more BITE into the air. It displaces a lot more VOLUME of air, but at the same air speed as the 2 blade.

This extra load of achieving this means the CS10 would either need more power to drive the larger volume OR it will run at a lower RPM.... than a low blade count fan.
So it is a bit of a 'diesel' power system, than a 'petrol' one (for a combustion engine analogy)..... (diesel more torque, petrol more BHP)

But that balance of torque to efflux speed is not something like two to one.... it is more like.... umm, a guess..... 20% more torque than low blade count fans, and thus 20% less efflux speed. Some sort of balance like that.
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Last edited by PeterVRC; Oct 11, 2012 at 05:25 PM. Reason: Spelling, DOH
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