Pressure release hole in BT not just for Altimeter

[Orestes Mayo]

Hello all. I was wondering about pressure holes in the BT.
I know that its used for the altimeter and placed just below the nose cone line but I was told to place a hole just above the fore MMT ring.
It is supposed to help with the ejection. Anyone have anything on this or heard of this? Thank you in advance.

 

[user 30299]

The pressure holes are for allowing the air to escape as the rocket rises and
the air in the rocket expands due to change in elevation. The air expansion
can cause the nose cone to pop off before your rocket reaches apogee, or
cause body sections to separate prematurely at a coupler location.

I usually locate the holes midpoint on the body tube, between the top-most
centering ring and and the nose cone. The same if the rocket has two sections,
with an avionics bay between the two body tubes; holes midpoint on the sections.

I'll shift the holes upward if I think the harnesses (shock cords) and chutes might
block the holes during flight.

 

[Hobie1dog]

Hello all. I was wondering about pressure holes in the BT.
I know that its used for the altimeter and placed just below the nose cone line but I was told to place a hole just above the fore MMT ring.
It is supposed to help with the ejection. Anyone have anything on this or heard of this? Thank you in advance.

nope

 

[cerving]

If you're launching a model rocket, you probably don't need to worry about early ejection due to trapped air pressure in the body tube. You're not going fast enough for the pressure not to reasonably equalize. With an HPR, that's a different story, especially if you're hitting Mach. One small hole in the body tube, in an area that won't be blocked by your chute, is all you need.

 

[user 30299]

nope

Ditto

 

[MClark]

I will put vent holes just below the coupler.
Idea is to let air out on ascent but not too much ejection gasses.