Density Alt Calculation

[shenweas]

Can anyone fill me in on the dew point used by the Dynon for calculating Density Altitude?

I have noticed that when useing the on-screen data from my Skyview and entering that into an E6B that I have a discrepancy in the calculated DA.

 

[dynonsupport]

Without complicating things by requiring a dew point to be keyed in (which you may not know at any given altitude at any given moment), it assumes a certain humidity, though I'm not sure of the value. A cursory look shows that it may not be the "worst case" possible spread, which is when is at 100% rel humidity (no temp/dewpoint spread). We're going to look into whether it makes sense to adjust the algorithm for DA.

 

[shenweas]

Any update on this?

 

[dynonsupport]

(This post edited from an earlier incorrect answer where we claimed 100% humidity assumption)

Sorry we never got back to you on this. The answer is that we calculate density altitude using a dry air calculation that is the general "standard" equation for density altitude calculation when you don't know the humidity.

This doesn't get you the highest possible density altitude (which is at 100% humidity) but clearly isn't going to match any other calculation that uses a different baseline or uses the real humidity.