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

Good luck.
 
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.
 
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.
 
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.
 
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!
 
That's the spirit!!!!


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


Seriously cool. That thing was gone in less than a blink.
 
Alright. Going to a launch next weekend and I want to start 2022 off with a bang (but not a cato). But I need to build a new rocket… again. Motor will once again be the I1299.

The airframe is going to be all fiberglass this time since I don’t have any more carbon for the time being. I’ve got a 1/16” sheet of fiberglass that the fins will be made of, and the tube will be rolled from some fiberglass cloth I have.

The electronics are going to be an Altus Metrum Easy Mini for deployment, and Featherweight GPS for tracking. The av-bay was 3d printed from ABS and held in place with four #4-40 set screws.

A00A980D-B940-4177-B4D3-02BF593EAACE.jpeg

Current estimations from Open Rocket are a tad more extreme than the last time around, but I’m sure that will change once I get actual weight and CG. But 287Gs is quite the number if you ask me. Unfortunate I won’t have a way to verify it
ADBA6A83-E867-4027-AA08-7F0CC2D9825C.png

Looking to fly this on New Year’s Day, so later tonight I’m going to be doing a bunch of work to try and get it ready.
 
No you are not crazy! I did a minimum diameter 38mm beast called the Speed of Money and fed it an I1299. It's cool to see is vanish. https://www.rocketryforum.com/threads/blackhawk-38-scratch-build.31616/
This was my build if anything in here helps you.

I’m starting to run out of failure modes, so hopefully this one goes well. But I agree, the vanishing rocket trick is really cool to watch.

Here’s a photo taken by Jim Wilkerson of my latest attempt at XPRS. 6DE186CD-22A0-4EF3-9EA8-86FDDDB7E0C9.jpeg
 
So the launch this weekend with TRAPHX was cancelled due to weather earlier this week. As a result I haven’t done much to get the rocket ready. Still need to cut fins out, and cut the tube to size, but that’s pretty much the majority of the work along with bonding the fins to the tube. I expect I can knock out the entire thing in a weekend if I just put the time to it
 
That motor is way cool. Looks like the rocket teleported to a different dimension. I have a 30 ounce 38mm MD I'm going to put an I 500 in. It's a LOC motor tube and hardened balsa nose cone. The fins are 1/4 ply. We will see what happens. I'm already planning the next one. Good luck and may the Rocket Gods smile on you.
 
That motor is way cool. Looks like the rocket teleported to a different dimension. I have a 30 ounce 38mm MD I'm going to put an I 500 in. It's a LOC motor tube and hardened balsa nose cone. The fins are 1/4 ply. We will see what happens. I'm already planning the next one. Good luck and may the Rocket Gods smile on you.
Good luck your flight as well. I500 sounds pretty spicy for a rocket like that
 
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
I don't know much about these super-high G flights. Is it possible the propellant grains collapsed under that kind of load? Is that a thing?
 
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