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Sep 10, 2001, 11:40 AM
Electriaddict
dorysch1's Avatar

spinner or not


spinner or no spinner? I am in the process of building a new duct\fuse for my tutor should I eliminate the spinner on the rotor ?
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Sep 10, 2001, 04:41 PM
EDF Head
Haldor's Avatar
Only if the spinner represent a problem for you. There must be some loss without it but to what extent isnt sure. Scott Black flies hit F86 without and it dont appear to miss it. I guess YMMV.

So its flying now - great!
-Haldor
Sep 10, 2001, 04:43 PM
Fixed Wing Fanatic
Jim Walker's Avatar
I'm no expert on flow dynamics and I'm new to EDF, but from what I've read so far on this forum, everything that smooths airflow through the duct is very important.

Without the spinner, air will have to change direction very suddenly as it hits the hub face vs. flowing smoothly around the spinner into the fan blades.

I've learned that small things like this can take a huge toll on fan efficiency. Just my .02 worth, by all means get a second opinion....

Jim
Sep 10, 2001, 05:12 PM
Electriaddict
dorysch1's Avatar
I was thinking of making a tubular director inside the ducting to direct air away from the hub? or am I just wasting time and server space heheeheh
Sep 10, 2001, 08:43 PM
EDF Jet Jam 2017, June 15-18
Kevin Cox's Avatar
I also fly without a spinner. You could balance it but it always seem to run smoother without it and at a little more RPMs so did I win or lose? It flys just as fast and makes less noise. I'm happy
Sep 13, 2001, 06:56 PM
Scott Black, Montreal
sblack's Avatar
I fly mine with no spinner (HW609 fan). It does not seem to be nearly as critical as the inlet lip. Maybe I am losing 1 or 2% eff. but I can't notice it. I just couldn't get the darn thing to run smoothly so I took it off. Vibration will also cost you power.

sb
Sep 14, 2001, 10:03 AM
Electriaddict
dorysch1's Avatar
that will be more weight I can shed Thanks ! hopefully I can get it up again (the plane that is) before it snows here I want to build something to put my speed600 motor in to fly around in the winter not sure what though
Sep 14, 2001, 01:29 PM
Lithium Member
Herb's Avatar
My experience is that it depends on the model, and in particular on the inlet ducting. If the airflow has already a slight turbulence at and around the spinner location, it won't matter much whether it's on or off. It seems the air will create its own spinner... I was quite astonished on some of my earlier models to notice the absence of any detectable effect when you took the spinner off. If the ducting is really straight & smooth I have noticed though some significant changes in sound when you take the spinner off, ie increased turbulence.

If you do have the time and patience, I would suggest though to painstakingly balance the prop and spinner, it's worth the effort,

http://aeneas.ps.uci.edu/edf/fan/balancer_1.jpg

One thing that seems to have very little effect (around less than 1/2 oz of st thrust in a HW-609) is the streamlined carbon fiber cone aft of the motor,

http://aeneas.ps.uci.edu/edf/mig17/p3010006.jpg
Last edited by Herb; Sep 14, 2001 at 01:34 PM.


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