Two-stage P to O Space Shot attempt at BALLS 30

Andrej

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High altitude ignition for the upper stage has been a problem for other teams, how did you accomplish it?
Sustainer was ignited with a boron /potassium nitrate igniter that was screwed in a forward closure. 20 grams of pellets was housed in a wire mesh basket.
Bellow is a photo of the igniter. Violet thing is a latex cover that covers the wire mesh basket.

20211116_001305.jpg
 

RGClark

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Sustainer was ignited with a boron /potassium nitrate igniter that was screwed in a forward closure. 20 grams of pellets was housed in a wire mesh basket.
Bellow is a photo of the igniter. Violet thing is a latex cover that covers the wire mesh basket.

View attachment 549471

Was that your own design or a common igniter for a sustainer stage?

Bob Clark
 

RGClark

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OK. I recognize this is a form of a BKNO3 igniter that has been discussed for upper stage ignition. There were some safety concerns I had about it being used for example by university teams.

Bob Clark
 

FredA

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Bob - can you refresh us with your safety concerns?
This looks like a great implementation in that it bolts in the top for a late-add.
 

waltr

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Safety concern is that the Igniter is installed before putting the motor into the rocket. Therefore, the motor has ingiter in place before moving it out to the pad and while getting the rocket onto the pad.

This goes against the policy of only installing the igniter After the rocket in on the pad and pointed up and recovery electronics armed.
 

tfish

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Safety concern is that the Igniter is installed before putting the motor into the rocket. Therefore, the motor has ingiter in place before moving it out to the pad and while getting the rocket onto the pad.

This goes against the policy of only installing the igniter After the rocket in on the pad and pointed up and recovery electronics armed.
Projects like this are normally "put together" at/on the pad.

*There was one project a couple/few years ago..where the motor/igniter lit while being removed from the bed of a pickup...plastic bed liner. Igniter not shunted etc...lessons learned .

Tony
 

plugger

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Just FYI the 483d is for 483 days ago.
Just circling back to this as I've got a question. Do FeatherWeight GPS trackers still transmit LoRa packets when the GPS firmware limits are exceeded resulting in no GPS fixes (eg above 500m/s or above 50km agl)? I only ask as all the screens shared in this thread have LAT/LONG fixes and I'm just not quite sure how or if the unit transmits when it's exceeded the GPS chipset firmware limitations.
 

Adrian A

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Just circling back to this as I've got a question. Do FeatherWeight GPS trackers still transmit LoRa packets when the GPS firmware limits are exceeded resulting in no GPS fixes (eg above 500m/s or above 50km agl)? I only ask as all the screens shared in this thread have LAT/LONG fixes and I'm just not quite sure how or if the unit transmits when it's exceeded the GPS chipset firmware limitations.
Yes, the tracker keeps transmitting. You can follow the packet counters increasing and watch the signal strength on the comm page.

A goal for the Blue Raven and updated tracker software is for Blue Raven inertial navigation data to be sent within the airframe over Bluetooth to the tracker and then transmitted by over LoRa to the ground.
 

wclaybaugh2

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Sustainer was ignited with a boron /potassium nitrate igniter that was screwed in a forward closure. 20 grams of pellets was housed in a wire mesh basket.
Bellow is a photo of the igniter. Violet thing is a latex cover that covers the wire mesh basket.

View attachment 549471

I first saw this type of initiator used on the Crisalli / Garboden RRS Dart launch of 1996. That vehicle used two redundant initiators that were screwed into the side of the vehicle at the bulkhead as the last action before connecting them to the blasting cable and retreating 1000 feet for launch.

A full description can be found here: https://www.rrs.org/2022/07/29/building-a-crisalli-igniter/

Bill
 
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