Nosecone Electronics Venting

[Mark Weidhaas]

I'm building an L3 project that will be dual deployment from a single compartment. I am considering putting the redundant drogue deployment electronics in the nosecone. My question is twofold. First, where is the best place to vent a nosecone? I'm thinking below the nosecone base, somewhere through the shoulder area. Second, should the baro based electronics be isolated from the deployment compartment so the ejection pressure can not effect the baro sensors?

 

[Voyager1]

You might want to consider head end deployment (HED). There’s a good thread here:
https://www.rocketryforum.com/threa...oyment-details-explanations-requested.129482/

 

[Buckeye]

Second, should the baro based electronics be isolated from the deployment compartment so the ejection pressure can not effect the baro sensors?

Umm, yes. Have you flown altimeter deployment before this L3 project?

 

[crossfire]

I have done it in the NC. Vent holes were in the NC shoulder. All worked as it should.

 

[MClark]

Use accelerometer based deployment, venting not required.

M

 

[Buckeye]

Use accelerometer based deployment, venting not required.

M

Unless you use much better acclerometers than me, I have never gotten a good apogee detection. Then, they are useless for main deployment. So, baro is the way to go for deployment, and accel is the way to gather more flight data.

 

[mpitfield]

I have many rockets that have baro based altimeters in the nosecone and I asked the same question years ago when I made my first. The rule I try to follow is to place the holes as close to the bottom of the flat area, as possible. This has never failed me, but not knowing your nosecone design YMMV. If you place them on the curved spot I was advised that it could increase pressure. Just past the curved spot and it can also be affected by pressure, "due to laminar" something. So you want it well past that area where the airflow attaches back to the airframe.

This is my regurgitated version, so you might want to check me, but I believe it is "mostly" correct.

 

[rharshberger]

I typically place my static ports just above the airframe and nosecone joint or above the bulkhead for plastic nosecone conversions. Any data from the altimeter will be noisy but apogee deployment is unaffected afaict.

 

[jderimig]

You want the vent where there is no risk of separated flow. This is generally just above the nosecone/airframe joint. Below on the shoulder is risky for nosecones such as conical NC and especially Nike Smoke nosecones.

 

[David Schwantz]

If you do go through the NC shoulder, make sure you "pin" the NC and air frame so they will not rotate and close your vent hole.