Easy Question

[Kruegon]

To be completely honest, I got tired of reading threads with no luck. Simple question.

Does the Jolly Logic Chute Release require a vent hole like altimeters?

My gut says yes. How else can it measure its altitude? But confirmation would be appreciated.

 

[tim cubbedge]

No - not needed. I still put an 1/8" vent hole in all my rockets though.

Here's a thread where John Bean chimed in.

https://www.rocketryforum.com/showthread.php?132483-Jolly-Logic-Chute-release&p=1556149#post1556149

 

[jrkennedy2]

Nope, it measures on the pad (or before when you power it on) which will equalize even without holes, unless you have a wicked-tight assembly. After ejection at apogee it is out in the open and can read alt there.

Then again, maybe I'm misunderstanding the question...

 

[smarra01]

I would think you would want a vent hole to keep the pressure equalized so that the rocket does not separate prematurely before apogee.

.

 

[Handeman]

I would think you would want a vent hole to keep the pressure equalized so that the rocket does not separate prematurely before apogee.

.

yes, but not needed for the JLCR

 

[cerving]

It's almost impossible to make a payload bay so airtight that an apogee-only detection device won't work. You DO need the vent holes for recording altimeters to get an accurate flight profile, and you DO need a vent in your payload bay if you're flying near Mach, especially with VMax or ST motors, because the high acceleration can cause a premature deployment due to the pressure difference between the inside and outside if the trapped air can't vent out fast enough.

 

[John Beans]

All correct. Strictly speaking, no vent needed just for Chute Release. But if you also have a recording altimeter, it will need vents. And any vents you need to maintain fuselage pressure equilibrium, as noted.

 

[r66astro]

I have two love them! Going to get two more. Let a guy use one last weekend (Tripoli Ft. Myers) with some great looking Estes kit bash. With G80. First flight without 1/2 mile + landing. Second flight < 50 yards.
Bill