J. Phil Thien's Projects

I am following Retired2, and I think that tubing you used is more appropriate than straws. However this IS quite a head scratcher, the only question i had after watching the videos was the bell-mouth outlet seemed to be a bit deeper in the separator on the later video. Don't know if it makes much of a difference, I assume you played around with that since you have little markings on the side... And then again, as you say, there is little loss in performance and lower noise: so you could just call it a success. Plus the whole setup looks really nice!

Laugh your heads off, it even has duct tape! However the functionality is impressive, I needed a mobile solution to clean out 100years of mice turds, dust, and rotten wood in my attic:

1- it pulls more dust out of cracks that i had previously passed over with a standard wet/dry shop vac with pleated paper filter (had to it off every 10min)

2- The first 1/2 hour of gentle sawdust and dust vacuuming the filter was gray but no accumulation, the bucket had 2 kg (~1lb) of junk.

3- after, I hit thick piles of turds, old bits of insulation and chunks of plaster for 1/2 hour, the filter has 100g of dust and the bucket had 3 kg of junk.

Pretty? Durable? NO
Useful? Portable? Yes
Efficient? maybe

quasi-specs: vacuum is a heavy duty Miele (~2000W) that refuses to die w/ 1.5" inlet, 10" separator bucket (unfortunately with a taper in the opposite direction than desired, so there is a permanent spin of fines in the top corner), semi-rectangular transition from a 1.5" inlet shop vac hose, and yes, a cardboard baffle plate suspended by the threaded rods.

Nice test write up. Concerning the blower inlet spin issue (since it is not really a problem), you could steal a handful of straws from McD's, cut them in half, pack them into your bell mouth, and set them in place with superglue. And if the blower doesn't immediately rip them out and shred them (probably not covered in the warranty) then you can see if there is more air resistance due to the straws that you lose to the inlet spin. I doubt there would be a significant gain.

Oh and to other readers who are wondering about my sanity, I did not pull the straws out of my @55, test wind tunnels usually have a honeycomb panel before the test section to linearize the flow. Straws are cheaper! All may doubt my sanity when I post pictures for my 3gal bucket prototype I just built for 99 cents. I'l save that for a different thread...

Retired, looks great. I have experience with anemometers and would not vouch for cheap wind or sailing versions for ductwork measurements. I suggest building a simple orifice plate with water manometer readout (coffee is easier to see). Plus it will cost you nothing but time.

http://en.wikipedia.org/wiki/Orifice_plate