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Propeller-thrust ratio

Started by Aravind298, August 22, 2017, 08:44:26 PM

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Aravind298

Has anybody ever tried to map the thrust produced by each unit cm of the propeller? Like at which place of the prop. the most thrust is produced and at which place the least?

Also anybody with experience in propeller designing may PM me.

Thanks :)

swapnilnimbalkar

I think thrust produced by a propeller is even at all given points.

Since tip of a blade moves faster than the part near center, that is the reason why blades are more inclined towards the center.

pnkyjs

very nice idea, there is a difficulty in mapping such a property w.r.t. the propeller because after cutting up a propeller into single unit , this single unit would not behave in same manner as when this unit works when attached to the entire propeller . so best way would be to set up an arrangement in a wind tunnel and rotate the propeller in streamlines of smoke and put many sensors radially outward at varying distance from centre to measure the pressure differences. Then a clear picture would emerge at which position that particular propeller is most efficient. Also the efficiency points would change for varying RPM . It would be interesting to also find the pressure variation in moving airflow as opposed to a standstill airflow in front of the propellor.
V911
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pnkyjs

my 10cents of gyaan !

Thanks.
V911
V977
XFX 450 V2
Scratchbuild foamies galore

Aravind298

@ Swapnilnimbalkar, I don't think it's same throughout the propeller. Since you can see the surface of propeller is not the same throughout.
Anyways, I'll be conducting some tests :)

Aravind298

@pnkyjs, that was really informative! Well I can't afford to test it in a wind tunnel, I'll try my best to create a similar environment to test the propeller.

madaquif

http://www.instructables.com/id/DIY-Wind-Tunnel-20-Project-Paperclip/
follow this to know the exact results...

kindly share your experience if you happen to build a tunnel....

gud luck.
Regards

MadAquif...

4 D RC ....SURFACE WATER AIR N SPACE

swapnilnimbalkar

@Arvind298

just googled it, found this, it may be relevant

http://www.explainthatstuff.com/how-propellers-work.html

Read this "Why a propeller has twisted blades"

Aravind298

#8
Thanks to Swapnilnimbalkar & mada! What I thought of, was to measure the thrust produced by every cm. of the propeller. Each centimeter of thrust will be measured through a separate precision weighing system.
But here's the downside:

1)I'm not sure how much efficient would it be, but I just wanted a ratio b/w each part of the propeller.
2)Lots of weighing machines would be needed (like at least 5-6 pieces).
3)The configuration has to be changed at will for each size of propeller.
4) Have to spend a lot of time in it :P