Static Pressure Hole Location

For the SL100 Stratologger the user manual recommends the holes be located as far as possible from body tube irregularities to minimize pressure disturbances caused by turbulent air flow over the body tube.

What are people's experiences with placing these holes in a "not so perfect " location? Maybe just below a nosecone or above/below a transition or even in the mid section of a transition.

A project I'm working on incorporates the altimeter bay inside the the transition. I need to determine the best location for the sampling holes.

If you HAD to do it near a transition, put it in the shoulder of the larger diameter end. It should work, but it won't be very accurate. If you're not doing dual deploy, just an altimeter, you can put a vent hole in the body tube and a vent from the transition into the tube.

Try searching this topic. It comes up a lot. The answers are the same - putting sampling holes in funny places is usually not a problem.

Here is one recent discussion:

https://www.rocketryforum.com/showthread.php?124661-Nose-cone-AV-bay-Sample-hole

I've put them in the base of the nose cone and at the rear of the rocket between the fins. The chute came out at the right time and the altitude numbers were what I was expecting.

Thinking of putting them in the lower (larger diameter) shoulder of the transition.

For deployment purposes, as long as your altimeter has some kind of filtering and mach-transition handling (and all of the modern ones do), it really doesn't matter that much where you put the holes. The rocket is going to be moving relatively slowly when these events occur, so the aerodynamic effects will be relatively small and therefore the pressure/altitude readings should be reasonably accurate. If you're doing data logging, the location is somewhat more important, putting them in a spot that may be a source of pressure buildup or voiding may cause some anomolies in your graph but it shouldn't affect deployment events.

That makes a lot of sense. Thank you.