Blimps and dolphins

We returned home with no problem after the NASCAR races, and since the trip was uneventful, I'd like to answer a common question we get as we travel the country.

Why does the blimp bob up and down like a porpoise when it's flying?

No, that's not just us having fun up there. It has to do with rising hot air and the speed that we fly. When flying on a commercial airplane, you've probably noticed that it gets a little bumpy just after take off and right before landing. At low altitudes, an airliner encounters up and down drafts due to unequal heating of the earth. (Imagine how much heat a blacktop parking lot emits versus a nice cool lake.) Since the airliner is moving at high speeds, passengers only feel slight turbulence when encountering updrafts.

Now take that same principle and apply it to slow-moving, low-altitude cruising blimps. When we fly into an updraft, the blimp's nose is pushed upward. As soon as the blimp pilot reacts by pitching the nose lower, the same updraft is now pushing on the tail, giving the opposite effect.

As a blimp pilot, I am used to the bobbing, but I know it probably looks a little strange from the ground.