Level 2 Cert with Piercer 98 - Need Advice!

[STOPPIE]

I'm gearing up for my Level 2 certification, and I'm planning to use the Piercer 98 by Wildman for the big moment. Super excited but also in need of some advice, especially on the electronics front.

Here's the deal: I'm thinking of going for a head-end deployment with a twist. Planning to use electronics to pop the main chute around 400 feet, and let the drogue do its thing with the motor ejection at apogee. (correction J520W-13)

Now, I thought I'd throw it out here - anyone got some wisdom to share? Any tips or tricks for this setup? Maybe you've tried something similar? Or maybe you've got an epic story about why I should rethink my plan?

 

[rfjustin]

I'm gearing up for my Level 2 certification, and I'm planning to use the Piercer 98 by Wildman for the big moment. Super excited but also in need of some advice, especially on the electronics front.

Here's the deal: I'm thinking of going for a head-end deployment with a twist. Planning to use electronics to pop the main chute around 400 feet, and let the drogue do its thing with the motor (rocking an Aerotech J90W-6) ejection at apogee.

Now, I thought I'd throw it out here - anyone got some wisdom to share? Any tips or tricks for this setup? Maybe you've tried something similar? Or maybe you've got an epic story about why I should rethink my plan? Lay it on me!

Have you simmed this combo? J-90 is a bit light for a chunky 4" glass rocket. The J-460 would be a better choice in the same size case.

Also, why not leverage the drogue and main events of the altimeter and just use the motor deploy for back-up? And are you really saying 6 second delay after motor burn?

 

[Titan II]

Is the alt dual deploy? If so, why waste a perfectly good channel? Use it for the drogue and the motor as backup.

 

[Handeman]

As an RSO, I wouldn't let that heavy fiberglass rocket fly on a J90W. Way too low of TTW ratio. At 0.2 seconds, the motor is only up to about 20-30 Ns.

As a former Prefect I would be worried about allowing a cert flight when you don't seem to understand the thrust curve and effects that has on launch rail speeds and altitudes. That motor choice is a huge red flag.

I have nothing against using just DD and no motor back up, but you need to have a motor that gets it off the pad at sufficient speed.

 

[kswing]

I have a Piercer and I've flown it on a J520W and it worked well. I think it reached about 2400'. I would recommend using the altimeter at apogee with the motor ejection as a backup. I've seen ejection charges not work properly and I wouldn't want something this heavy coming in fast.

Here's a link to my build thread: https://www.rocketryforum.com/threads/build-thread-wildman-piercer-98.169902/ Note that the Piercer kit I received had 4 fins, but, I think now it just comes with 3 fins.

Also, be sure to use a very solid motor size adapter (probably something made of aluminum). My first launch on this rocket I used a wooden/cardboard one that looked solid but wasn't solid enough and it didn't go well.