Missile Works 29mm S.M.A.R.T. sled adapter idea/question

I have a MWC 29mm S.M.A.R.T. sled, great quality, really like it!
Thanks Jim and Andrew!
The question is: if I adapt it for 38mm, 54mm and 2.56" BT's using centering rings( see picture), how big should the static pressure holes be in the other body tubes and will this even work to give accurate data and deployment?
Thoughts, comments!

The size of the vent holes is dependent on the volume of the av-bay. The larger the holes the quicker the pressure in the bay will equalize with the outside pressure. If the holes are too big, crosswinds can affect the altimeter, especially on the pad.

I really doubt that crosswinds can have a detrimental effect on newer altimeters with their software filtering capabilities. On the older ones, if the holes were too big, the crosswinds could cause deployment on the pad in RARE cases.

IMHO the biggest issue today is too small of holes. If it takes too long to equalize the pressure, the rocket will arch over and be gaining speed on the way down when it finally senses the pressure in no longer dropping and fires the apogee charge.

I think I would size the vent holes in the airframe per formula's available. The adapter I would just cut a bunch of the tube open so I could access altimeter. This tube is just to contain it, and has all thread through it so the tube is not really doing much. This will eliminate a separate set of holes in the adapter.


Mark Koelsch
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