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Thread: Home made horizontal milling machine.

  1. #31
    [email protected] tonyfoale's Avatar
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    Quote Originally Posted by crazypj View Post
    Been a while since I could get online, been looking after grandson last 2 yrs. I thought 2 yr olds were close to 'perpetual motion' but 3 is even closer.
    Leon Moss was founder of LEDAR, died in a hang gliding accident if I remember right.
    I had to scroll back to see why you were talking about Leon. I knew of Leon, in our previous discussion I was just indicating that I was not familiar with his work although I knew of him.

    Quote Originally Posted by crazypj View Post
    Don't know if you've looked into it at all but could one of the cheap weather anemometers be used to measure airflow in flow bench? It would work along the lines of Vizard's 'floating point' bench with a ~5hp vacuum cleaner/shop vac
    I looked into many ways to measure air flow for the bench. Most benches use an orifice plate but the flow coefficients are low, 50 to 60%. I used a venturi in place of an orifice plate, coeff around 96 to 98%, so I only need a vacumn source of roughly 1/2 that I would with the orifice. Combined with electronic differential pressure transducers it is very accurate and highly repeatable. Most/all orifice machines have to change out plates at different flow rates, even when doing a single test over a range of valve openings on the same port. With my venturi I have to change out nothing. Testing is very quick. My software averages 100 readings over a set period (usually 5 secs). All I have to do is set the valve lift, push a button, wait 5 secs and repeat for as many steps as I want. My software does the rest.

    I don't see any price or functional reason to use a weather anemometer over what I have.

    Home made horizontal milling machine.-tempsensor01.jpg Click for full size images.
    Ventururi with temp sensor attached. See my old post on ruggedized temp sensors.

    Home made horizontal milling machine.-board_03.jpg Home made horizontal milling machine.-board_06.jpg Home made horizontal milling machine.-board_08.jpg
    Some pix of the black box and DP sensors. There are humidity, baro and temp on the board as well as a temp sensor on the venturi and port. These parameters allow the results to be compensated for different atmospheric conditions. I obtain indistinguishable results from testing at 0 deg when I lived in NH, USA and testing at 30 deg here in Spain. My workshop is always 30 deg in summer.

    I use a floating plenum pressure as Vizard has as well. However, I realised when I made my first bench a long time back that even without electronic sensors you could make accurate manometers from clear plastic tube and coloured water to actually measure flow. That is unlike Vizard's first efforts where he only got a "better or worse" indication. I had real flow numbers from the outset.

    As you suggest I do use a motor from the biggest shop vac that I could find on a trip to the US. I extracted the motor which was light enough for a suitcase and left the rest behind.

    Anyway I'll leave more on the flow bench subject until I make a full post about that. Maybe this discussion will bring it to the top of my list to document. I was intending on doing something on an LVT that I made for my shock dyno or some modifications to put my bead blaster on steroids.
    Last edited by tonyfoale; 01-01-2019 at 03:57 AM. Reason: Minor correction.

  2. #32
    crazypj's Avatar
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    Hi Tony,
    Happy New Year.
    That's a really neat solution, I won't hold my breath but will be waiting for a full write up (LOL)
    I've seen cheap anemometers on sale around $40.00, obviously not best quality but if repeatable results would be OK for a yes or no on flow improvements. (pretty sure they just use something like a 2 wire computer fan and measure generated voltage?)
    I used flow bench a few times when I taught at MMI (Motorcycle Mechanics Institute, Orlando) Superflow 110. Not sure how accurate it was but it did show improvements (or otherwise ;( )
    Reading Vizard's work/books over the years I suspect he isn't burning any bridges but doesn't think 10" pressure drop extrapolation is best way to go?
    Got some good results for a semi-pro MX'er on his YZF250, he jumped about 30 spots in national ranking
    3yr old is sleeping at present, I get a lot of time to think trash but not much time to actually do anything (plus watch too much You Tube)

  3. #33
    [email protected] tonyfoale's Avatar
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    Quote Originally Posted by crazypj View Post
    Hi Tony,
    I've seen cheap anemometers on sale around $40.00, obviously not best quality but if repeatable results would be OK for a yes or no on flow improvements.
    Why settle for a "yes/no" when it is no more expensive or more work to get some actual repeatable numbers. A bench that I built a long time ago for almost nothing, which used my smallish shop vac missing the filter, and for which I still have tested items gave results better than 1% when compared with my current machine. The only thing wrong with using simple manometers is that testing takes longer and results have to be either entered manually into software or you have to do it all manually.

    Home made horizontal milling machine.-flowbench.jpg click to enlarge.

    This was much later than my first bench but it is about as simple as it can be, but that does not detract from its accuracy. Note that even though this was all manual I still had a weather station there to calculate correction factors. Sometimes for budget reasons you have to make or use "yes/no" equipment but there really is no need for that with a basic flow bench. Having said that, there is a difference between getting accurate data from any testing programme and how closely that data represents reality. This is never more true than with flow testing. You take static flow measurements whereas reality is rapidly irregularly pulsing flow with liquid being injected into the stream.

  4. #34
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    Hope this 'conversation' isn't messing up thread?
    I've read a lot about flow benches over the last 50+ yrs (Mostly by D. Vizard ,LOL) I always wondered about valve haed shape, at very fast lift couldn't it create something of a vacuum behind it or would pulse pressure in port tend to pressurise entire port at a resonant frequency? (when it comes 'on the pipe' )not expecting reply right now, I think your about 6 hrs ahead so it's about 1:40am in Spain? My brother in Britain used to call around 7~8:00 am British time, 2~3am in Florida. I never could get him to understand the time difference

  5. #35
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    Quote Originally Posted by crazypj View Post
    Hope this 'conversation' isn't messing up thread?
    I've read a lot about flow benches over the last 50+ yrs (Mostly by D. Vizard ,LOL) I always wondered about valve haed shape, at very fast lift couldn't it create something of a vacuum behind it
    The velocity of valve heads is actually quite low as is the displacement. There will be some reduced pressure but it will be minor.
    Valve head shape is very important for flow though.

    You might find this of interest Some flow tests

  6. #36
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    Thanks tonyfoale! We've added your Manometer to our Measuring and Marking category,
    as well as to your builder page: tonyfoale's Homemade Tools. Your receipt:





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