When it first came out, the page illustrating mountain waves was quite horrible, and we criticized it:
Fortunately, that didn't last long. A few months after its original publication, the course was updated and greatly improved, although it still wasn't perfect:
Yes, there is still a fair amount to criticize here, but this is probably the limit of what a typical airplane driver needs to understand about mountain waves. After all, the target audience of the Air Safety Institute seems to be airplane pilots, exclusively.
Which is a shame, since the pilots of gliders, helicopters, ultralights, and balloons probably could also use some well-made refresher courses on safety.
P.S. You should join AOPA.
10 comments:
Finally the rotors turn in the right direction...lennies still too low though. NEXT...
The relative height and space between waves still not accurate, as I understand them. Very difficult to get a realustic feel of this phenomenon. Better illustration needed.
Yes, a better illustration is needed to get a realistic feel. But that's not the point of the lesson.
This lesson teaches the power pilot what the clouds look like, and the relative locations of the rough and smooth air. That's all. It's not meant for glider pilots, and it says nothing at all about how to soar the wave.
It's a cartoon; it's not meant to be a scaled diagram. It serves its purpose.
Does it matter to a glider pilot whether the rotor is clockwise or counterclockwise?
Yes. Understanding which way they turn is key to centering those weird thermals that lean upwind.
Geez Rick! You whined so much about their "cartoons" that I passed your criticism on to AOPA. They actually listened to you and acted upon your advice. You don't get that much respect from anyone in the PMSC!
I'm OK, with that, as long as they don't make a habit of reading this blog!
I think Rick is one of the most respected in the PMSC, I don't know why you don't see it.
Why do thermals lean upwind from a rotor?
And are there such animals in the first place?
Sure, there is an adiabatic layer underneath the wave. (This is the dark blue layer in the image.)
The boundary between the stable and unstable layers is where all the shear turbulence is. And since the wave system is standing still, this is where the rotors form. (In the image, the boundary between dark and light blue should be going through the roll clouds).
Picture a bubble of air that leaves the ground somewhere downwind of the mountain and is rising up to the shear layer. When it gets to the boundary, it gets dragged "upwind" (against the prevailing wind) by the rotor.
Your strategy when you find yourself drifting upwind while circling is to get as high as you can and then transition upwind into the bottom of the wave.
Post a Comment