[roc-chat] Re: PET2+ OK for sustainer airstart?

  • From: Terry McKiernan <terry@xxxxxxxxxxxxx>
  • To: roc-chat@xxxxxxxxxxxxx
  • Date: Sun, 13 May 2018 10:26:42 -0700

All good points; I appreciate the discussion and advice.  I can certainly see how ROCstock needs to be more safety-conscious with all the spectators, especially kids running around.

OK so, getting down to specifics: let's say I'll get an altimeter with some smarts to do my airstart.  How about the RRC3 (about $75)?  Or do I need the Raven ($155) or something even more capable?  Just to repeat myself yet again, the 2nd stage payload will also have an EggTimer TRS which will handle the motor ejection charges.  I just need something to handle the airstart.

Thanks!

Terry

On 5/13/2018 9:17 AM, David Erbas-White wrote:

On 5/13/2018 8:56 AM, Allen Farrington wrote:
I agree with David that this discussion is exactly what this chat is for!

The idea of doing a sim and setting the logic triggers is what most staged rocket flyers do. It’s what I do as well.

The “if required” clause in the guidelines are there to allow for some discretion based on the range situation. For example, at a ROC launch, especially a ROCStock Saturday, we have lots of spectators and new LPR flyers so I would stray to the more safe configuration. If it were Friday morning when it’s primarily experienced flyers in a small crowd, I’d let you fly the timers, put it on the back row, and call it a heads-up flight.

Additionally, while your rockets are previously flown, you are trying a new ISC and if it fails during boost, you could light a tumbling sustainer. That’s a bad situation at a ROC launch, but would be OK from the away cell at black rock.

You've said it far better than I did.  I was mentally thinking of our 'normal' Saturday morning, heavily attended with numerous spectators type of launches in my response.  I agree with all of the above...

David Erbas-White




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