Muammer Yildiz Magnet Motor

[TinselKoala]

Here's another online prop calculator:
http://adamone.rchomepage.com/calc_thrust.htm
Using its "APC 16x10" and its default atmosphere parameters I get 46.4 Watts. More than I expected, for sure, but still a lot less than what Yildiz has advertised.
Nine candy bars.

[TinselKoala]

Does anyone know where the RPM numbers are coming from? Is an optical tachometer being used? Is it counting blade passages? Is it possible that it is reading 2600 blade passages per minute, which would be 1300 RPM?

Power to turn the prop goes as the cube of the RPM, so half the RPM means one-eighth the power required. Two candy bars.

[ramset]

I was going to say at 14 watts for a 16 inch prop
No way !!
I don't get You tube ATM ,is the settup in the Tube?
or free air?


putting the blade into that tube with the back pressure from the other blade is analogous to placing it into water.[OK water is a bit dramatic .however the load increase will be huge.]


As will the watts required to drive it!


Since you have all the propeller  toys already TK and with all that spare "internet Time".


Some chewing Gum a couple of staples and a cardboard tube.
we could even Calibrate the little out put genny load [TinMan knows How to do that ]


?
photo below courtesy of
Physics Prof
quote

I found the meter used to measure RPM's - it also can measure temperature (non-contact): http://www.extech.com/instruments/product.asp?catid=21&prodid=16 It is seen in one of the vids from 10 April.  Note the reading - 1517 (RPM), for this run at about 3pm on 10 April.

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[TinselKoala]

The setup is fairly described in the quote from Sterling's correspondent above. The prop is sitting well out in front of the motor, there isn't really any shroud but when he puts the plastic box on it, it effectively acts as an "end plate". I've demonstrated how adding an endplate can actually _increase_ the RPM of a model airplane propeller at a given input power, but that's not really relevant here.
I'm happy with the 46 Watt figure that the online calculator comes up with as ballpark -- IF the RPM can be trusted. I am having doubts now, based on the sound, and I'd like to see something about how the RPM is measured: what kind of optical tach, does it correct for blade count, is it calibrated against some standard, etc.
Because if the thing is actually counting blades and not correcting, then it's indicating 2600 blades per minute and not 2600 RPM which means 1300 RPM and that cuts the power requirement by a factor of 8.

[TinselKoala]

photo below courtesy of
Physics Prof

I found the meter used to measure RPM's - it also can measure temperature (non-contact):
http://www.extech.com/instruments/product.asp?catid=21&prodid=16

It is seen in one of the vids from 10 April.  Note the reading - 1517 (RPM), for this run at about 3pm on 10 April.

You are kidding, right? OK, that thing has no correction for blade number. Where on the motor is he measuring the RPM? If it's at the blades.... then it should read 5200 for a motor turning 2600 RPM.