Okay Aviators, Density Altitude question

CYanchycki

CYanchycki

Club Coordinator
This discussion is going to center around the Beggs tuner and what I will the 2 camps in how the tuner is used.

I know there is a camp that adjusts by DA (density altitude) and what Rodney has choosen to do. As he mentioned he did not want to buy a Kestrel so he decided and found a process taht works for him as has been discussed in the tuner again thread.

In regards to using DA I would like a few answers from the aviators out there.

To calculate DA using say a APP on my I-Phone, I need to know the Air temperature, Dew Point temperature, the current altitude, and finally the BP (barometric pressure) in inches of Mercury.

Now what I did find out that the Kestrel 4000 uses the altitude it sees, the air temp it reads, dew point temp, and not the pressure it reads but the standard of 29.92 hg. Is that the correct BP that is used when DA is calculated? I thought the DA that is used at ground level is the current BP you read.

Could this be clarified.

See I have a Kestrel 3500 and do not want to get another. It can give me all I need to calculate DA but it does not have the DA feature built into it. I can then plug the data into my I-Phone APP to calculate it and log it.

So I guess Gene Beggs, you are an aviator can you elaborate? I want to find a standard that can be used and shared if the desire arises. Or do I just say stay with the way the Kestrel 4000 calculates the DA?

Hope this makes what I am trying to say........

Thanks all in advance
Calvin
 
CYanchycki said:
This discussion is going to center around the Beggs tuner and what I will the 2 camps in how the tuner is used.

I know there is a camp that adjusts by DA (density altitude) and what Rodney has choosen to do. As he mentioned he did not want to buy a Kestrel so he decided and found a process taht works for him as has been discussed in the tuner again thread.

In regards to using DA I would like a few answers from the aviators out there.

To calculate DA using say a APP on my I-Phone, I need to know the Air temperature, Dew Point temperature, the current altitude, and finally the BP (barometric pressure) in inches of Mercury.

Now what I did find out that the Kestrel 4000 uses the altitude it sees, the air temp it reads, dew point temp, and not the pressure it reads but the standard of 29.92 hg. Is that the correct BP that is used when DA is calculated? I thought the DA that is used at ground level is the current BP you read.

Could this be clarified.

See I have a Kestrel 3500 and do not want to get another. It can give me all I need to calculate DA but it does not have the DA feature built into it. I can then plug the data into my I-Phone APP to calculate it and log it.

So I guess Gene Beggs, you are an aviator can you elaborate? I want to find a standard that can be used and shared if the desire arises. Or do I just say stay with the way the Kestrel 4000 calculates the DA?

Hope this makes what I am trying to say........

Thanks all in advance
Calvin
Click to expand...




Calvin

Density altitude (DA) is pressure altitude adjusted for temperature. Set an altimeter to 29.92 and it will read pressure altitude which may or may not be the same as field elevation. If barometric pressure is unusually high, pressure altitude will be somewhat lower than actual field elevation and vice versa. There are sites on Google that can figure DA for you if you know the pressure altitude and temperature. But why bother? I concluded long ago that outside air temperature is the only thing you need to monitor. Keep it simple. :)

Gene Beggs
 
Gene Beggs said:
Calvin

Density altitude (DA) is pressure altitude adjusted for temperature. Set an altimeter to 29.92 and it will read pressure altitude which may or may not be the same as field elevation. If barometric pressure is unusually high, pressure altitude will be somewhat lower than actual field elevation and vice versa. There are sites on Google that can figure DA for you if you know the pressure altitude and temperature. But why bother? I concluded long ago that outside air temperature is the only thing you need to monitor. Keep it simple. :)

Gene Beggs
Click to expand...

well yeahhh but, but, Gene.... he asked for AVIATORS. You ever actually fly a plane??

;)

al
 
I was a Chief Flight Instructor and we lived with Density Altutude (DA) every day.

Density altitude is the altitude in the International Standard Atmosphere at which the air density would be equal to the actual air density at the place of observation, or, in other words, the height when measured in terms of the density of the air rather than the distance from the ground. "Density Altitude" is the pressure altitude adjusted for non-standard temperature.

Both an increase in temperature and, to a much lesser degree, humidity will cause an increase in density altitude. Thus, in hot and humid conditions, the density altitude at a particular location may be significantly higher than the true altitude.

Air density is perhaps the single most important factor affecting aircraft performance. It has a direct bearing on:[1]

The lift generated by the wings — reduction in air density reduces the wing's lift.

The efficiency of the propeller or rotor — which for a propeller (effectively an airfoil) behaves similarly to lift on wings.
The power output of the engine — power output depends on oxygen intake, so the engine output is reduced as the equivalent "dry air" density decreases and produces even less power as moisture displaces oxygen in more humid conditions.
Aircraft taking off from a "hot and high" airport such as the Quito Airport or Mexico City are at a significant aerodynamic disadvantage. The following effects result from a density altitude which is higher than the actual physical altitude:[1]

The aircraft will accelerate slower on takeoff as a result of reduced power production.
The aircraft will need to achieve a higher true airspeed to attain the same lift - this implies both a longer takeoff roll and a higher true airspeed which must be maintained when airborne to avoid stalling.
The aircraft will climb slower as the result of reduced power production and lift.

Due to these performance issues, a plane's takeoff weight may need to be lowered or takeoffs may need to be scheduled for cooler times of the day. Wind direction and runway slope may need to be taken into account.

Here is a video to help: http://www.youtube.com/watch?v=RaDMpRRKWwQ

Hope this helps.

George
 
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Well said Boyd.
Gene is one of those people I referred to in another post about being willing to bend over backwards to help someone do better and shoot better.
He has given a lot of his own time and money to the sport trying to develop things that will help the rest of us. And there/this is a HUGE difference between one Gene B. and the other Gene b.
Thanks Gene Beggs.
 
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Gene Beggs said:
Calvin

Density altitude (DA) is pressure altitude adjusted for temperature. Set an altimeter to 29.92 and it will read pressure altitude which may or may not be the same as field elevation. If barometric pressure is unusually high, pressure altitude will be somewhat lower than actual field elevation and vice versa. There are sites on Google that can figure DA for you if you know the pressure altitude and temperature. But why bother? I concluded long ago that outside air temperature is the only thing you need to monitor. Keep it simple. :)

Gene Beggs
Click to expand...

Love the kiss method
 
FBecigneul said:
I consider myself quite the apiator also.
Since I installed a Kestrel 4000 on the hives Flora, Fauna, and Flossie have produced much more honey and the quality is higher as well. I believe they have learned to fly better once they knew the density altitude.

I just noticed you guys are talking about aviators. I thought you said apiators.
Click to expand...



Francis, you're a real hoot! :p

Gene Beggs
 
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