On a heavy windy day, departing from Hayward, in the San Francisco area, the tower asked me to do a short crosswind for a downwind departure, to avoid San Fran Class Bravo. I did that, climbing at VX, and then turning downwind, where I encountered a 30 knots tail wind. Not good for VX. The plane started shaking violently, engine sounded really rough. I immediately leveled off, and set the plane to a 150' VSI. It was better, but got my wife very concerned.

Basically, the plane was about to stall, and the propeller was stalling as well. This is something to remember about turning into a heavy tailwind.

It happened to me as well a few months before, departing from Ontario at night. Incoming planes were noting about 30knots wind shear at 1000'agl. On departure, the same thing happened, climbing straight out into a tail wind. It got so bad that I almost turned around to land but it was fine with only 100'vsi. Thank goodness for GPS terrain. It was at night, and it was not very comfortable, specially being almost at gross.

The lesson for me is that it is very important to notice winds aloft, departing an airport, especially in known wind shear areas.

Franck Valles