Thread: New Product Change Sun 10 blade 70mm
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Old Oct 11, 2012, 05:59 PM
PeterVRC is online now
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hehe, I don't think you can match the CFM/Efflux. If one fan is designed a certain way - blade count, pitch, area covered - then it has certain total properties. And then another fan will have its own different ones.
You could match off ONE of those values.... CFM or Efflux Speed.... but you can't alter their ratio in that given fan.

For a rough guide, as mentioned, throw another 5% power at it.

I have not tested - and it would be hard to quantify accurately really - but from what I see, it seems if you get Thrust X from a CS10, and had that same thrust (benched) from another low blade count fan, the CS10 installed in a plane will have a lower top speed.
Again, probably because thrust measured on a bench can come from efflux or CFM, but throw that into a plane and top speed is set by efflux mainly (as long as the CFM is still adequate for the load it propels)..
The CS10 powered plane will sustain climb better.... more 'torque'. Which always can get grey when testing, because a faster entry speed will visually look like a faster plane "climbed" as well anyway. But if you had all the measuring abilities, you should see the CS10 is like a 'diesel pulling a load up a hill' = less speed loss, as it was slower but with more torque all the way.

This means to get the same fast top speed, you had to throw more power at the CS10 and whether you wanted it or not you also got more torque - which is where that 'wasted' extra power that they 'need' (versus low blade count) went. So you still are getting something for that power, whether you wanted it or not (torque).
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