Re: Trajectory vs. Humidity
Crow Mag, what was the source of that calculation? JBM? Or a hand held computer?
700, in jest I say: You quote Uncle Sam's Misguided Children? [img]images/icons/grin.gif[/img] You are dot on about the molecular weight. FWIW Dept., Rinker said in his book that humid air was denser, Vaughn said dry air is denser...Vaughn wins without debate.
Guess my question was answered in part by Crow Mag's post, ie. not much effect. On the other hand there is a reason they refer to it as RELATIVE HUMIDITY. The warmer it is, the more effect it must have. Maybe unimportant in cold winter air, BUT, if you're shooting prairie dogs at a mile on a warm summer day...well who knows?
I do not have the performance charts for this but in tropical environments(S.E. Asia) the effect of humidity was potentially as great as Density Altitude on any given day. DA=pressure altitude adjusted for Temp. 4000' DA's at sea level were routine there. In 1970 or so some bright lad let us in on a little secret: 90-100% humidity on hot days could nearly double the figure above, the significance being that a UH-1 could hover at gross weight out of ground effect with a 4000' DA. Doubling that number cut the payload in half OR ensured an LZ marked with black smoke. [img]images/icons/frown.gif[/img] The Devil is in the details.