Yet another 38mm min diameter rocket

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T34zac

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I have had an awful track record when it comes to 38mm min diameter rockets.

Back in 2014, I made my first one that flew on a CTI I800 Vmax. Shredded the phenolic airframe very quickly.
FD88F1AD-68EF-4B85-9903-5E6972BC98C7.jpeg

2015 I tried again with a carbon airframe, better stability margin and carbon fins with a CTI I216 classic. That motor cato’d.
8B817169-C9FE-4A3D-AAC1-FF538BB6D21D.jpeg

February 2021, I revive the previous rocket (since it survived the cato with some burn marks on the side), and try it again on another I216. The apogee charge fails and it punches a hole through the ice of the frozen lake we were flying off of.
5BD31B52-E39E-4EA7-A73D-33AC3D029D5A.jpeg

March 2021, new one with a fiberglass airframe and carbon fins. AT I1299 Warp-9 as the motor. That cato’d at about 245 Gs of acceleration.
F00BF5FB-980C-44D6-8413-45F670F9AA68.jpeg

So here I am again. Attempting another I1299 powered min diameter rocket. Am I crazy? Maybe. But somethings I just can’t leave unfinished (so yes there will be another I216 min diameter rocket at some point).
2AA97598-8C0E-473C-BC15-57434CF68052.jpeg

Looking to pull about 250 Gs with this one and reach an altitude of about 10,500’. Should break mach 1 before 100’ and mach 2 before 500’. Will be flying at XPRS this weekend.
 

rocketace

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Good luck!!
Any electronics on board to record the high G's?
 

boatgeek

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I have to acknowledge the third photo looks like the lunar surface.
When I first saw the picture, I assumed it was going to be a "We never found the rocket, so we assume it landed on the Moon" joke.
 

T34zac

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I have to acknowledge the third photo looks like the lunar surface.

When I first saw the picture, I assumed it was going to be a "We never found the rocket, so we assume it landed on the Moon" joke.
That was a frozen lake. The rocket penetrated over a foot of ice and was never found. Only tell that the hole pictured was made by my rocket was the tiny fluorescent paint chips around the hole, and the last known GPS coordinates were about 200’ above the hole
 

Donnager

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That was a frozen lake. The rocket penetrated over a foot of ice and was never found. Only tell that the hole pictured was made by my rocket was the tiny fluorescent paint chips around the hole, and the last known GPS coordinates were about 200’ above the hole
Replacement rocket--Ice Pick.
 

ECayemberg

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What are you using for recovery electronics? Do they ride in the nose cone? How are you working out the vent holes?

Good luck.
 

T34zac

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Got to fly this one on Friday afternoon once the waiver opened back up for the rest of the day. Motor didn’t cato this time but there was an early separation, exact cause is still unknown.

22353D67-FD8C-4827-8587-F1E4E1CD7154.png

Nosecone and parachute were found about 1000 feet past the away pads. The tracker was halfway between the nosecone and away pads. And the booster was just in front of the Uber Rail, sticking out of the playa. Motor casing was unharmed, but the front end of the tube and electronics were toast.

C7DC6E1C-45CF-4AC8-AD28-42C15A17ECDD.jpeg

I’ll upload a couple videos when I get a chance.
 

watheyak

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Bummer... Sorry to hear about that. Been there!

Was there a vent hole in the parachute compartment?

It's good at letting the evil spirits out. Or higher pressure air. They're really the same thing.
 

T34zac

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Bummer... Sorry to hear about that. Been there!

Was there a vent hole in the parachute compartment?

It's good at letting the evil spirits out. Or higher pressure air. They're really the same thing.
Yeah these 38mm rockets are tearing me apart here.

Yes there was a pressure hole and shear pin. I’m quite surprised it separated unless it was an early ejection. Once I get a chance I’ll be checking the nosecone for black powder residue.
 

T34zac

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Decided I’m not going to let this failure get the best of me. I ordered three more I1299s over the weekend, so I’m going to be trying to get one of these to hold together for an entire flight sometime in the future.

Future attempts will also need a high G accelerometer even if it’s only for recording and not attached to a flight computer. I want to see just how fast and how many Gs one of these things pulls!
 

mo2872

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That's the spirit!!!!


Or it's insanity.......you pick. /sarc


Seriously cool. That thing was gone in less than a blink.
 

T34zac

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That's the spirit!!!!


Or it's insanity.......you pick. /sarc


Seriously cool. That thing was gone in less than a blink.
Insanity might be the right word. But you know, 3rd time’s the charm right?
 

T34zac

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I approve of this flame-to-rocket-length ratio. Good luck on your next try!
Haha yeah, a crazy flame:rocket ratio was one of the goals for this.

I’m already trying to figure out ways to make the rocket even shorter to increase that effect.
 
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