Altitude/Pressure Question

I just got my new Kestral weather station and I have a question. When calibrating the unit do you use the standard 29.92 in/hg barometric and then read the "station pressure" directly from the meter? Or do you need to know the actual altitude of the track you are at and use that to calculate your corrected Barometric pressure? The manual for the unit discribes procedures to perform either calibration but I need to now basically what the "standard" procedure is (if there is one)

I hope I explained that correctly.

I plan to use Davenports jet software but I haven't got it yet, does anybody know what that software requires?

Thanks
Corey

 

That is how I set my Kestrel...

EDB

 

Yup, me too.

 

Kestral

Thanks for the info guys. I did a little more reading and they said in the manual that you can get altitudes from google earth. I tried that and yes the altitudes are dead on. I also phoned the airport to see what thier altitude is and it matched google earth. The cool thing I found is you can use the satalite image to go to any track in the world, and zoom right in a the starting line to get the altiude.

If I know this information, is this as accurate as using 29.92 and the station pressure?

When I put in the altitude of the shop (2011 ft), my barometric reads 29.86 give or take. Now, if I put in the 29.92 barometric my altitude is off a little about 2025.

The density altitude on both methods is not exactly the same but its only about +/- about 20-25 ft. Am I splitting hairs here or does this difference matter. Granted I'm not running Top Fuel or even Top Alk just a door car, but if I'm going to read the DA I would like to have to most accurate info I can.

Thanks again for all the great insight

Corey

 

I feel it doesn' tmatter if it is 20-25 or 250 feet off. As long as it is the same everytime! All you are charting is the change.

 

Kestral

Thanks for all the info guys.

Corey

 

Make sure you use the same altimeter every time. They can very greatly with different altimeters. There is a reason why we have them in our hands and not in the instrument panel of an airplane.

 

Altitude

I don't plan on comparing info with anyone, so the Kestral unit I have will be the only one I ever use.


Corey

 

How easy is it to get hold of an old altimeter in the states? I have tried in the UK and all I can find are gauges that need a sender unit to work which is nit very useful.

If Mythbusters is to be believed though the states is full of aircraft salvage yards where you can just grab what you want easily.

 

Check ebay.com

EDB

 

I'm from Europ to, same problem.
When I was in the states some years ago I walked into a small airfield (with a small shop) and asked for the maintance department.
I was shoved into a hanger were a mechanic was upside down in a cessna.
He had several used ones on the shelf and adviced me to take a no longer certified one for usd 50. It is in fine working order and does not lose calibration.
I check it ones a year and drag it al over europe.

Or, for the easy way, check ebay as the previous poster sugested.

Hans

 

speedwaymotors.com sells the altimeter for $125.00

 

I've had no luck with ebay in the past but am tracking 2 ex-RAF items at the moment. Cheers for the speedwaymotors link, think we have bought a few things from them before.

 

Ha ha i'm watching those RAF ones too, i don't need one yet so good luck !

 

As long as it isn't you I am bidding against! How is the bus coming along?

 

It's getting there thanks , just having the injection stuff flowed then it's new valve springs and hopefully fire it up, still doing stuff like the copper leafing on the name on the sides etc but once it makes a noise I'll be much happier with it ! hows things with you ? oh and i haven't bid on it !