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Re: dyson motors
Posted: Wed Oct 14, 2015 4:16 pm
by damunk
cheers tony.
someone said what kind of bench i want to make.
Well there's not much to it.
flowbendesign.jpg
Re: dyson motors
Posted: Thu Oct 15, 2015 12:50 am
by storm
Tony wrote:damunk wrote:
Also when you talk about more motors combined "stealing" from performance from one another.
Is this because we should design the pipe work from each motor similar to a car exhaust manifold then link them all to one main pipe like an exhaust so there is no back pressure problem....
Where there is only one motor, the air moves towards the motor intake hole from all directions, and accelerates as its gets closer to the motor intake. Its a pretty orderly process.
If you have a whole cluster of motors
located very close together, the air becomes very confused and turbulent around the motor intakes.
It cannot make up its mind which motor to flow into. If the whole thing is then further confined into a relatively small blower box on the intake side, the air around all the motor intakes will go frantic and be quite turbulent.
The motors fight each other for air, and the result is each motor flows slightly less than it would if it was the only motor running.
As you add more motors to your bench, the final airflow will always be slightly less than the number of motors multiplied by the rated flow of a single motor. Its not a huge reduction, but its definitely there.
Tony what would happen if there were staggered stacks put on the motor intakes like staggered stacks put on hipo engines (like in the attached picture)? Would this alleviate the "stealing"?
Re: dyson motors
Posted: Thu Oct 15, 2015 12:58 am
by Tony
storm wrote:Tony what would happen if there were staggered stacks put on the motor intakes like staggered stacks put on hipo engines (like in the attached picture)? Would this alleviate the "stealing"?
I would expect so, but it would take up a lot of room.
the alternative is just to fit one motor extra, and gain that way.
Re: dyson motors
Posted: Thu Oct 15, 2015 3:47 am
by damunk
Just to add the Sealey CX105 trolley costs around £65 inc delivery (UK) brand new.
I bought a referb one for £45.00 inc delivery.
Overall Size (W x D x H): 890 x 420 x 800mm
Shelf Size (W x D x H): 790 x 405 x 80mm
For small blocks you can put the hole in the middle and is big enough to cover the whole range.
I might put a block of wood (60mm thickness) on the shelf so the engine is raised up (higher up).
Re: dyson motors
Posted: Thu Oct 15, 2015 3:51 am
by Tony
The way that trolley appears to be built, it looks like the top can be unbolted and turned upside down.
That would give a flat surface for the top.
Re: dyson motors
Posted: Thu Oct 15, 2015 7:07 am
by RACEPUMPER
So your going with a pitot bench? The performance trends style?
Jim
Re: dyson motors
Posted: Thu Oct 15, 2015 1:54 pm
by damunk
Tony wrote:The way that trolley appears to be built, it looks like the top can be unbolted and turned upside down.
That would give a flat surface for the top.
cool. Yeah it can. Just checked. Will confirm once I've turned it upside down.
Re: dyson motors
Posted: Sat Oct 17, 2015 3:18 pm
by damunk
Just realized buying two 119996 from the UK might equate to 4 of the cheap Panasonic motors after they have been shipped here and paid for the import tax.
Could 180 cfm be achieved at 28" with two 119996's?
http://www.rossbrownsales.com.au/files/ ... asheet.pdf
Just looking at the data sheet, it has got a similar cfm at 3/4 inch orifice compared to the cheap Panasonic ones. Just 10cfm more.
Have I missed something here>?
Re: dyson motors
Posted: Sat Oct 17, 2015 5:27 pm
by Tony
damunk wrote:
Could 180 cfm be achieved at 28" with two 119996's?
It should come pretty close, 82.9 CFM at 42.7 inches at 240v
Re: dyson motors
Posted: Sat Oct 17, 2015 7:34 pm
by damunk
RACEPUMPER wrote:So your going with a pitot bench? The performance trends style?
Jim
Jim,
sorry I don't understand.
I want to make the pipe from the motors up to the test piece with a way to test the flow, velocity .
Just want it simple as poss and accurate for the money I spend.
I'm porting and polishing a 1.4 head for personal use but at the same time learning about the flowbench builds. I read on some forum posts that 1.4 heads flow from 140-160cfm whether that's right.
And reading more about pressure drops. I've decided to spend the extra money on better motors.
I think two/three good motors might be enough for me now.