PDA

View Full Version : Real gust?



spyboy
03-30-2008, 11:39 PM
Is that peak gust after 1pm today real? Looks like the winds were dieing down to almost nothing and then a 111mph gust? Did a jet buzz the OBS?

Kirk

Bill O
03-31-2008, 01:12 AM
In a word....no.

Okay, I've seen their wind chart look like that during a summer thunderstorm, but not under near record high pressure and clear skies.

My guess is they were doing some maintenance to purge water droplets from the system.

bclark
03-31-2008, 08:21 AM
Is that peak gust after 1pm today real? Looks like the winds were dieing down to almost nothing and then a 111mph gust? Did a jet buzz the OBS?

Kirk

I was just waiting for someone to notice that and question it. I'm actually surprised it took this long!


My guess is they were doing some maintenance to purge water droplets from the system.

Close. Actually, Steve and I spent the better part of 8 or 9 hours working on the entire pitot system. We replaced old deteriorating rubber hoses with new clear plastic tubing. We cut down some lengths of tubing running to some of the instruments because they were unnecessarily long. We took out some junctions that were no longer necessary. We checked every joint between copper tubing or instruments and clear plastic tubing, replaced tubing and resealed the joints as necessary, and zip tied each joint.

The spike in wind speed that spyboy noticed occurred while I was using our Druck Pressure Calibrator, which is made specifically to calibrate pitot systems. This device applies a pressure to the system, basically mimicking a real wind. I was performing a leak test on the system, but I forgot to tell our digital database to ignore the data coming from the Setra pressure transducer. Oops.

All this work was for the most part, just preventative maintenance. We have had some issues we have had this winter with condensation getting into the system, which then has the potential to freeze and block the pitot lines, causing erroneous wind speed measurements. This is likely happening because there is a very small leak in the system somewhere. So, since it was such a nice day and we were able to use other instruments to determine our wind speed, we decided this was the day to do what we could to fix any possible leaks in the lines going to the instruments. We also did this in anticipation of a high wind event Tuesday night into Wednesday. We want to prevent the problems we had during the big wind event on the 21st, where the other shift had to pump ice and condensation out of the system many times through the course of the day.

We did what we can do for now. If there is still a problem, it is likely in one of the joints of the copper tubing that runs from the top of our tower down to the weather room. That won't be able to be worked on until summer, when we also have big plans to build new pitots and make some other big changes.

edog2007
03-31-2008, 08:49 AM
Did you find any problems?
If you did,would that effect the wind speed for the 21st?
Zip ties?:D
You don't use duct tape,do you?:D

bclark
03-31-2008, 09:27 AM
Did you find any problems?
If you did,would that effect the wind speed for the 21st?


To quote myself:


All this work was for the most part, just preventative maintenance.

So no, there were no problems that were found that would lead me to believe that any wind speeds we have measure are inaccurate. The system we have in place is an excellent system, but like anything of this nature, it needs maintenance and repairs at times to keep it working correctly and efficiently.


Zip ties?:D

These are handy to ensure that joints between clear plastic tubing used in the system, is securely attached to either copper tubing, or instruments. Yesterday, we used a combo of two zip ties, making sure the buckles were not lined up so that a good seal is created. When shift change comes up on Wednesday(maybe Thursday), we are going to have them bring up a different type of clip that does a better job of uniformly sealing the plastic to the copper without having to use more than 1.


You don't use duct tape,do you?:D

Although in my experience, duct tape is a handy tool, none is used in the pitot system.

edog2007
03-31-2008, 09:44 AM
Quote

We are going to have them bring up a different type of clip that does a better job of uniformly sealing the plastic to the copper without having to use more than 1.







Like those used in irrigation?