Help with measuring cowl pressure differential - Page 12

lostpilot28 · #**111** 12-13-2011, 04:17 PM

Quote:

Originally Posted by DanH

Ok, let's see how accurate it is. Easy to do; tee the meter to a water manometer made from vinyl tubing and a yardstick. Make sure the static end for each meter is in the same location and oriented the same. Have your assistant hold the pitot tube out the window of your car and note the readings (you drive!). If accurate, the meter will read exactly twice the rise of the water in one of the tubes, or put another way, it will equal the difference in water level between the two legs of the manometer.

Couldn't I simplify that by just putting one end of each tube out the window and having the other end free inside? They should measure the same, no? less T's this way I think.

DanH · #**112** 12-13-2011, 05:08 PM

Quote:

Originally Posted by lostpilot28

Couldn't I simplify that by just putting one end of each tube out the window and having the other end free inside? They should measure the same, no? less T's this way I think.

I dunno about you Sonny. I try to give you a triple cool, Dynamic Science Guy, zoom around in your sports car setup..... and you bitch about too many tees

As punishment I give you the boring, cheap, dirt simple no-tee method. You can do it over the kitchen sink. No worshipful assistant required. Just you and about 10 feet of 1/2" vinyl tube. Hook up as pictured, pour water in one end, measure the height difference and compare with the meter reading. Make sure the connection at the meter is air tight.

Lars · #**113** 12-13-2011, 05:46 PM

Fixed it for you (sorry, it's getting close to 5PM here on the west coast)...

longranger · #**114** 12-13-2011, 06:01 PM

I'll drink to that! As soon as I'm done here I'm heading out to Chapter 1000's annual "Festivus" party. Rumor has it there will be a new Festivus Pole for "airing of greivances".

Now back to your regularly scheduled thread...

lostpilot28 · #**115** 12-13-2011, 08:52 PM

Quote:

Originally Posted by DanH

I dunno about you Sonny. I try to give you a triple cool, Dynamic Science Guy, zoom around in your sports car setup..... and you bitch about too many tees

As punishment I give you the boring, cheap, dirt simple no-tee method. You can do it over the kitchen sink. No worshipful assistant required. Just you and about 10 feet of 1/2" vinyl tube. Hook up as pictured, pour water in one end, measure the height difference and compare with the meter reading. Make sure the connection at the meter is air tight.

Ahh, c'mon, Dan...if I could do it the first way you mentioned, I wouldn't have needed to spend the $40 on the digital instrument!

GrayHawk · #**116** 12-13-2011, 08:54 PM

Quote:

Originally Posted by lostpilot28

Ahh, c'mon, Dan...if I could do it the first way you mentioned, I wouldn't have needed to spend the $40 on the digital instrument!

I heard that Idaho just passed a new law: "No manometering while driving".

RV8R999 · #**117** 12-13-2011, 09:12 PM

very funny!

I like the idea of using the car to test the sensitivity of the piccolo tube. set up a pitot line outside the car and have an assistant hold the piccolo as a static source changing orientation while observing the pressure readings.

rocketbob · #**118** 12-13-2011, 09:27 PM

I have a heated pitot/static probe design I'm going to turn out on my lathe this weekend. The heater is just going to be a few turns of nichrome wire inside the "nose" of the pitot. Looks like I'll have the only VW car in the world with a functioning heated pitot.

lostpilot28 · #**119** 12-13-2011, 09:29 PM

Quote:

Originally Posted by GrayHawk

I heard that Idaho just passed a new law: "No manometering while driving".

I would've gotten a ticket on the drive home from work today if that were the case!

DanH · #**120** 12-14-2011, 09:16 AM

Quote:

Originally Posted by lostpilot28

Ahh, c'mon, Dan...if I could do it the first way you mentioned, I wouldn't have needed to spend the $40 on the digital instrument!

Seriously, we do want to know if the $40 digital is any good. Only way to know is to calibrate. In this case the standard is really, really cheap (water) and so is the apparatus.

Add a tiny bit of dishwashing liquid to the water to reduce surface tension.

The kitchen sink method is actually the better way. I just didn't think of it until after posting the first one

Quote:

Originally Posted by Lars

Fixed it for you (sorry, it's getting close to 5PM here on the west coast)...

That's funny....I don't care who 'ya are.