question about pvc blades

[snake21]

hi friends,just want to know about the difference in resistance between blades from 6 inch pipe and blades from 8 inch pipe.

in fact,i have a set of 3 blades coming from 6 inch pipe for my ametek 38vdc but most of the time,it will record 8-10 vdc,i was planning to change to 8 inch pipe blades to test.

what do you advise friends?

thanks

[tanner0441]

Hi

I assume you are aiming for a 12V system, working on 5,200 RPM at 36V you will have to hit around 1600 RPM to get near cut in so your present blades may be at their limit. I doubt if bigger and heavier blades will spin any faster.

Brian.

[snake21]

hi,the motor is rated at 1150 rpm at 36v.i think blades made with 6 inch pipe has more resistance compared to blades made from 8 inch pipe

what do you think

[tanner0441]

Hi

I made a set of blades from 4in PVC pipe, on a car alternator. It never managed to put anything into a battery but it did spin at over 500 RPM until one very windy night it was hit by a flying branch from a neighbours tree, that took one and a half of the three blades.

I still think small thin blades will spin faster than longer fat blades.

I am sure someone on here will have done what your trying and will comment for you.

Brian.

[zvizdic]

I think you need  propeller of 2 blades, not 3 to increase rpm .
And add a 1' on a diameter of rotor.
8" pipe is better in any way you look.

[Isaiah]

Are you using heavy or thin wall pvc?
Thin wall will work better for this project I take some scrap and cut a strip to covet the mounting holes in the blades and put the same hole pattern in them as the blades and we have had no cracking or break out in the mounting area.
 When you lay out your pattern on the pipe dont make your straight side square to the pipe drop it so the tip is down about a inch.
 this will give you the effect of  rifling in a rifle barrel. put your mounting holes in  so that  they are parell to the straight edge which should be the bottom edge.
 Hope I didnt confuse you.
Isaiah

[ghurd]

Snake,

Got your email from a few days ago.
Your computer is still full of viruses, and every time you check your email it sends me spam.
Due to the state of your computer and email accounts, Yahoo refuses to allow me to respond (that's one good thing about yahoo!).
About time to get that straightened out.

G-

[snake21]

hello ghurd,thanks for the reply.in fact,there is no problem with my pc but it is with my email.
anyways,i will try to fix this.thanks for informing me,i thought the problem was over.

this is what i sent you in the email.please try to help me in building this system.

thanks

''hello ghurd.

how are you,hope you are ok.hope you still remember me.

i am mailing you to ask if i can use your controller to activate a relay to dump excess power to grid using the cheap Chinese grid tie inverter.i have 3 controtroller,1 for dump,1 as lvd and 1 i think will be used to control the relay

if this is possible,would you be able to guide me through the process please?

my system was down for some month and now i am working on it again.

thanks''