Quantcast

Static Pressure Port size

The Rocketry Forum

Help Support The Rocketry Forum:

jdud

Well-Known Member
Joined
Jan 19, 2009
Messages
244
Reaction score
0
I've built a very small e-bay for a 54mm airframe to house my Missile Works rrc2 mini. Inside dimensions are 2" diam by 6" long. According to my calculations (based on Missile Works paperwork), the e-bay needs a single hole between 1/32 and 1/16". This seems awful small to me. Should I drill one large hole or 2 or 3 smaller holes? What size?
 

Zeus-cat

Well-Known Member
Joined
Mar 14, 2009
Messages
4,478
Reaction score
678
The hole(s) don't need to be very big to provide proper venting. I would use what the manufacturer recommends as they have tested these configurations and are making these recommendations based on experience.

If you use more than one hole, four equally spaced holes are a good idea. It reduces the effects of wind gusts. Remember, if you use four holes they can (and should) be 1/2 the diameter of the single hole. If you do the math, 4 holes of 1/2 the diameter of one hole equals the exact same area.
 

Graham Orr

Well-Known Member
Joined
Mar 14, 2009
Messages
297
Reaction score
0
The hole size (coupled with the volume of the bay) acts like a low-pass filter on the internal pressure. smaller holes provide more continuous curves though have latency problems. larger holes are more prone to pressure discontinuities (in data) though have better transient response.

for 54 mm, an adequate vent is probably 3/16" diameter or larger for most applications.
 
Top