What is your project for Thunda Down Under 2019?

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OverTheTop
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Re: What is your project for Thunda Down Under 2019?

Postby OverTheTop » Mon Jan 22, 2018 10:52 am

What is the official statement regarding the allowability of HEI (head end ignition) at the Thunda event? Is it a proscribed technique? Is it allowable with certain caveats? Some info on this would be great as there are a few multi-stage rockets to be flown there by the looks of it.
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drew
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Re: What is your project for Thunda Down Under 2019?

Postby drew » Mon Jan 22, 2018 4:17 pm

OverTheTop wrote:What is the official statement regarding the allowability of HEI (head end ignition) at the Thunda event? Is it a proscribed technique? Is it allowable with certain caveats? Some info on this would be great as there are a few multi-stage rockets to be flown there by the looks of it.


From the conversations I've had OTT this HEI hardware is kosher for all AMRS launches. I suspect one of the benefits of creating your own rocketry governing body is the ability to make rules that are a little more sane than other orgs, especially when it comes to this sort of modification that can easily be described as providing safer staging options. From a technical perspective I believe you have a much higher chance of success staging with HEI when compared with bottom lighting from the booster or leveraging conduit or tape wire for lighting a motor via sustainer electronics; especially with MD attempts.

All that said I'm 100% certain that I'm the only Australian customer that has this set of hardware so the answer might be different with other hardware, especially if it's home brewed and relatively untested. Charlie Ogino and Jim Hendricksen have put a lot of effort in these HEI forward closures to ensure both a safe experience and repeatable capability. They've been static tested and flown on numerous occasions from my understanding.

Finally, from my perspective HEI isn't the primary safety concern when it comes to staging, well configured staging electronics are the primary concern. I definitely don't want to light a L sustainer motor if my rocket is more than 12 deg off vertical when the ignition is meant to occur. IMHO the "logic" in flight computer programming that controls staging is much more important from a safe staging perspective when compared to commercial HEI hardware.

TLDR; Ask. I've asked Blake and Scoop regarding this hardware and their responses have been positive. YMMV dependent on HEI hardware leveraged and the testing regime it's been subjected to.
Andrew Hamilton
AMRS 28 L3
AMRS Records Committee Chairman
Max Alt AGL - 23,908ft - K300 - Balls 22
Max V - 2,488 ft/s, ~Mach 2.2 - M2250 - THUNDA 2015

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OverTheTop
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Re: What is your project for Thunda Down Under 2019?

Postby OverTheTop » Mon Jan 22, 2018 5:28 pm

Thanks for the comments Drew. So that is the official AMRS stance on HEI? If so, is it documented somewhere, and what are the requirements for using other HEI setups other than the CJ system?

Agreed. HEI is definitely not the main safety issue for staging. Not so bad if things go awry up at altitude when it lights, but an unintentional ignition during setup on the ground is more than just frightening.
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Re: What is your project for Thunda Down Under 2019?

Postby drew » Mon Jan 22, 2018 5:39 pm

OverTheTop wrote:So that is the official AMRS stance on HEI?

I didn't say that at all... :D I only said my conversations with Blake and Scoop regarding this HEI hardware have been positive.

OverTheTop wrote:HEI is definitely not the main safety issue for staging. Not so bad if things go awry up at altitude when it lights, but an unintentional ignition during setup on the ground is more than just frightening.

And this is where staging goes from "a good idea" to "did I just crap my pants?" :wink:
Andrew Hamilton
AMRS 28 L3
AMRS Records Committee Chairman
Max Alt AGL - 23,908ft - K300 - Balls 22
Max V - 2,488 ft/s, ~Mach 2.2 - M2250 - THUNDA 2015

drew
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Re: What is your project for Thunda Down Under 2019?

Postby drew » Mon Jan 22, 2018 5:48 pm

To be more pedantic, my conversations specifically regarding Carolina Composite Rocketry HEI hardware with Blake and Scoop have been positive. At an absolute minimum any HEI hardware will require appropriate due diligence from the flyer hoping to leverage it at an AMRS launch. To my knowledge the AMRS has no formal framework for HEI staging but I do plan to bring up this point in the near future in my "official" capacity as a Records Committee member.

I also expect more due diligence will be required to gain approval for staging shots that attempt to leverage HEI (and staging shots in general). Also remember that any flight that sims to 18k' or above requires it to be reviewed by the High Altitude Flight Review Committee (I'm not 100% sure that's what it's called) and so there is already a rough framework in place for managing many of these attempts at THUNDA, especially the more aggressive ones.
Andrew Hamilton
AMRS 28 L3
AMRS Records Committee Chairman
Max Alt AGL - 23,908ft - K300 - Balls 22
Max V - 2,488 ft/s, ~Mach 2.2 - M2250 - THUNDA 2015

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OverTheTop
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Re: What is your project for Thunda Down Under 2019?

Postby OverTheTop » Mon Jan 22, 2018 5:55 pm

Thanks Drew. I am looking at making my own HEI adaption and have been considering it for a number of years. It will, of course, be based around materials and methods that are up to the task.

I have a few other ideas around the safety theme too, but I don't want to hijack the thread too much :) .
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"Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)


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