Wow! Great links! I'll have to take time to peruse all that info...should be good food for mindsim. Regarding the compression of airflow, it may not be a factor in my first tests; however it will come into play with later upscale and larger motor/higher speed tests (if it gets to that point). Also I think nose cone shape may have some effect (especially at higher speeds) since cones like the Nike Smoke behave differently than the usual conical (ogive?) ones we see - I've read that sampling holes on the smoke should be farther away from the nose cone since that one creates odd readings close to the cone...I'd guess the shape creates a lower pressure area at the base since the air is pushed in a straight line away at an angle whereas a curved side profile of the normal conical cones likely allows the air to follow the curve due to the tendency of fluids to follow the surface of an object (Coanda effect?). On the topic of outlet & inlet size I think for the initial tests I'll try larger than inlet, same area as inlet and smaller than inlet. I think larger than inlet may be best since it would be least likely to create too much pressure inside the shroud (which means drag) and also would possibly allow the air to be drawn out of the slots on the back end more easily (we'll see). Thanks for all the homework prof!