Need Ducted fan flow rate info

[XTheOwl]

Hello,

I am looking for a ducted fan for a project.

I was wondering if anyone knew where to find or how to calculate flow rates for some ducted fan/motor combos.

Or maybe a CFM/RPM constant for a given fan?

Is there a ducted fan/motor combination that could put out 300+ cfm?

Thanks,

xto

[AirX]

What size fan do you need in this project?

Eric B.

[XTheOwl]

Well AirX, thats what im tryin to find out.

Anyone know where I can find flowrate data for various systems?

Thanks,

xto

[AirX]

There is no reall flowrate data on any of the fans available, it can be calculated from the swept area of the fan and the average blade pitch angle. I have posted on this subject a few times. The individual fan needs to be measured of course.

I did look up a few fans I have performed the required calculations on and the smallest fan tht can output 300CFM realistically is a 55mm and of course all the way up to 5 inch with slightly varying power levels.

Cheers,

Eric B.

[XTheOwl]

Thanks for the info AirX. If theres any way you could link me to your previous posts, that would be great. I did a search before, but came up empty.

Thanks again,

xto

[winmodels]

Hello, I am looking for a ducted fan for a project.
I was wondering if anyone knew where to find or how to calculate flow rates for some ducted fan/motor combos. Or maybe a CFM/RPM constant for a given fan? Is there a ducted fan/motor combination that could put out 300+ cfm? Thanks, xto

Hi xto

Eric has already given an answer to your question; cfm is not a useful term in EDFs - at least nobody uses it. It's more akin to the heating and ventilation branche.
Since this type of question crops up occasionally it would interest me what you want to do with that fan and the 300cfm? And what sort of pressure are you looking for?

Have fun with fans

Klaus

[XTheOwl]

Well, it is a bit off topic, so I appologize, but I'm lookin to build a larger scale hovercraft. I found some info on the web, but I figured there were a lot of experts on this forum.

Is there maybe a webpage that has the A-Z's of ducted fans? I could use any and every equation I can find.

Thanks again,

xto

[AirX]

Here is a link to a thread where Klaus has given a lot on the subject our looking for. My knowledge is dovetailed into his equations so this is the best avenue to answer your questions.

Eric B.

[winmodels]

Hi

here is the link which Eric is hiding somewhere :D

http://www.rcgroups.com/forums/showthread.php?t=463604

BTW 300cfm is really not very much for an EDF, it's about what my WM600 produces at 200W. The WM2000 at 1.5kW produces about 1200cfm, but at a much higher total pressure rise.

Have fun with fans

Klaus

[charlieoneseven]

For a hovercraft maybe why there are some not quite what your looking for answers.

[cyclops2]

CFM is the key to a real model Hovercraft. Try to calculate the following area.

Raise your model up to the right looking height and measure the sq. in. or ft. of the space between the bottom of the skirt and the floor.

Weigh the complete model.

You can now compute PSI and area-- you need to generate. Any Brand name fan company, cooling fans are ok, can tell you all the other "stuff you will need to know so you can then go to a .46 fan or whatever size.

9# of thrust out of a 5" DF is than usable data to the fan company.

Do the # collecting, check your facts , then call the fan people.

Piece of cake to them.

[AirX]

Hi

here is the link which Eric is hiding somewhere :D

http://www.rcgroups.com/forums/showthread.php?t=463604

BTW 300cfm is really not very much for an EDF, it's about what my WM600 produces at 200W. The WM2000 at 1.5kW produces about 1200cfm, but at a much higher total pressure rise.

Have fun with fans

Klaus
Klaus,

Thanks for the save, I thought I put it in the post.

Eric B.