Wednesday, May 18, 2011

Big motors - static tests

I always wonder how someone can spend the time (and money) on a large P or Q motor, and then not fly it. Even putting it in a giant rocket and getting a few thousand feet isn't really my style, but at least it is going somewhere. A Q motor can hit 100,000 feet! It is also interesting that static tests are not nearly as loud as the same motor in a rocket. Why is this? Perhaps the exhaust is simply pointing up rather than down (towards the crowd) in a rocket. Also, I suspect the airflow over a large airframe (even a thin P motor is going to be 6 inches in diameter) contributes to the sound level. Any ideas?


Ken Kzak said...

Right on both counts regarding rocket noise.

I shake my head at guys flying motors that big without adequate ground testing. Yeah, testing is expensive, but so is the vehicle, travel, etc.

Of course, a fully ground tested motor can still fail in flight.

R2K said...

Good point...