L3 Build - Starless Rogue

[pathtouch]

Howdy TRF gang. It took a little while for a free weekend and the weather to line up but there was finally a launch I could attend. This was just a test flight to make sure chutes were properly sized, new altimeters worked, recovery gear was up to snuff, and deployment charges work.

Despite temperatures in the teens and some wind to contend with, this one was fun as I convinced my dad to tag a long. K1050 put her up to about 2140 feet, and my new Eggtimer Proton is officially flight tested.



Anyways long story short I think (4) 4-40 shear pins on the drogue side is a bit excessive and seems a lot of my 6 gram deployment charge vented out the back instead of separating the rocket. Also at the pad my backup altimeter with a 7 gram charge didn't have continuity but I went ahead and sent it figuring the 125 foot per second fail safe would pop the main if the drogue didn't come out.

Guess what happened... be better than me and don't be afraid to take a rocket off the pad to double check electronics. We all hear that advice but until you almost lawn dart a rocket you never really listen to it! Would that backup have separated the drogue at apogee? Maybe, but I'll never know and now I get to repair this sucker:


Pretty wild zipper, can't believe how strong kevlar is. According to the altimeter the fail safe kick in and by the time it the main opened the rocket was going over 300fps. At least I know all my recovery hardware is properly sized and the rocket will break before the hardware! 1/4"-20 hardware throughout on a 40-lb rocket with motors is no problem.

Naturally I made a video of the this misadventure.

 

[bad_idea]

Sorry to see this, but looks like the rocket will fly again.

 

[tfish]

Thanks for sharing for others to learn from...

Tony

 

[JamesBenMoore]

Never like to see that happen but thanks for sharing. I look forward to seeing the repair process!

 

[rfjustin]

Thanks for sharing for others to learn from...

Tony

This, exactly this, thank you for sharing OP! Go fever bites hard, but you have learned the lesson and have the guts to share the nitty gritty.

Cheers!

 

[rocketgeek101]

Thanks for sharing the results of the first flight. It's pretty cool how smaller motors in a big rocket like this can arguably produce a more impressive visual spectacle than a larger motor that sends it out of sight!

Good luck with the repairs. At least the damage is mostly contained to the upper airframe which can be easily replaced.

I agree that 4x 4-40 pins seems excessive, but I'm still surprised a 6 gram charge failed to separate the sections! In your ground test video it separated with a good degree of authority. Was there a clear path for the ejection gasses to escape out the back?

I only used two 4-40 pins on my Ultimate Wildman for the drogue separation point (and 3 for the nose), and that has worked for me without issue, including on a flight to 13,000 ft.

 

[pathtouch]

Thanks for sharing the results of the first flight. It's pretty cool how smaller motors in a big rocket like this can arguably produce a more impressive visual spectacle than a larger motor that sends it out of sight!

Good luck with the repairs. At least the damage is mostly contained to the upper airframe which can be easily replaced.

I agree that 4x 4-40 pins seems excessive, but I'm still surprised a 6 gram charge failed to separate the sections! In your ground test video it separated with a good degree of authority. Was there a clear path for the ejection gasses to escape out the back?

I only used two 4-40 pins on my Ultimate Wildman for the drogue separation point (and 3 for the nose), and that has worked for me without issue, including on a flight to 13,000 ft.

Yea I think there was some slop around my 54-98mm adapter rings that let a lot blow by. I didn’t ground test with those. Another good lesson there.

 

[John Kemker]

Paint it black, then your theme song for the rocket can be: