12” Mega Punisher Build Thread

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Following this thread made me go back and review one of my last build threads posted on TRF.
"Tweety Bird" is a 7.5 inch rocket with five 54mm motor mounts, built in 2018 for LDRS and held by Tripoli Central California. Not quite the scale of this build, and definitely not done at the pace of this build, but an interesting study for those that are contemplating a large clustered high power rocket:

https://www.rocketryforum.com/threads/tweety-bird.144668

Sharon (my wife and "Hardline" here on TRF) is the driving force behind our rocketry hobby. I'm hard pressed to meet the goals she sets for our attendance at many of the launches here in the Southwest, not that I don't thoroughly enjoy the challenge. One of my favorite quotes is "My wife is a full time job."
 
Alright folks, I'm about halfway through my 1,400 mile trek back home to Idaho, so here's a recycled image!

The rocket is mostly done, with only finishing, painting, and electronics to be situated.

That's up to our boys @tjsnakez and @matttherocketman

I'm still working out logistics of when I'll be coming down for Airfest, but we got quite a lot done for a single week!

As of now, the rocket weighs 107 pounds loaded with recovery gear, which actually brings us in a bit lighter than we anticipated. Right now, sims are showing about 13k on our classified motor selection.

Thanks again to Taylor for hosting this build party, storing the rocket, and of course making all the parts so we basically just had a giant kit to build.

It's going to be a party in Argonia this year!

For now, I leave you with our best attempt at looking hard.

Videos should start rolling out on the construction of this beast next week! Of course, my Patreon supporters will get the full "feature length" build right off the bat!

Braden
20220619_111339.jpg
 
Very nice build guys . What will your first flight motor(s) combo be . 13k on a 12 inch airframe that's 107 pounds , I'm guessing around 23kns .
 
Alright! I thought we'd give this a shot since it seems like fun. Below is the link to the first video installment of this build. It premiers this Sunday, July 3rd at 9AM Mountain Time (8AM Pacific/11AM Eastern). If you're around and feel like popping in to watch, you'll be able to live chat as the video plays.

If you're not around for the premier, you'll still be able to watch this video with the link afterward.



Hope to see you there!
Braden
 
I also had the opportunity to test a thermite igniter in an L1940 a couple weeks ago. Instant on :)
Just wanted to test the sizing because 1G per 1000Ns seems to be a BS rule of thumb. It will work, but it does not scale linear and seems over energetic as the motors get larger. I used 2.5g on that motor.
D21D1253-C9DB-4F12-BDA7-996D53AE71F0.jpeg
 
Rail button inserts have been installed and primer has made it onto all pieces! Progress. After hours of filling and sanding on the booster, I believe we are almost there.

Btw the finishes on the PML pre glassed phenolic and the fwfg nosecone from unknown origin are incredible. Very little filling and sanding will be needed to make those look nice.

I have a wedding next weekend, but the plan is to shoot auto paint the weekend after that! :D

A0F1EB76-739A-4A68-A967-DB595605E1D5.jpeg3BF2580F-5907-4F85-AA03-CD25D8C77502.jpegE2B71325-D26F-412B-A3DB-8444ECF33F03.jpegAA8E07FC-87A4-48A1-AB34-48C569B44758.jpeg
 
Also, those are not the rail buttons we intend to use for the flight, but some rough 3d printed pieces that Braden had made to test. They are all threaded into the heaviest duty 1/4-20 threaded inserts I could find for easy replacement of rail guides.
 
Also, those are not the rail buttons we intend to use for the flight, but some rough 3d printed pieces that Braden had made to test. They are all threaded into the heaviest duty 1/4-20 threaded inserts I could find for easy replacement of rail guides.
I forgot if it’s been mentioned here or in the vids. What sort of rail will this beast use?
 
I take it you'll be painting the end of the NC silver to emulate the WM metal tip..? (Looks that way from the third pic)
I think you are seeing a shadow. There actually is a big metal tip on that cone, but I am painting the whole thing.
 
Sorry I'm coming to this build thread super late.

I saw in a previous post that the fin can centering rings are held in with screws. Is it just the screws, or do you have epoxy in there, as well?

Edit: A friend pointed me to the build videos. [The 19ish minute point of this answers that question](https://www.youtube.com/watch?v=09uTFE_lkHQ) and [about the 3 minute point of this video](https://www.youtube.com/watch?v=22Jlmvm-Jt8)

Yeah....that thing is solid.

-Kevin
 
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Sorry I'm coming to this build thread super late.

I saw in a previous post that the fin can centering rings are held in with screws. Is it just the screws, or do you have epoxy in there, as well?

Edit: A friend pointed me to the build videos. [The 19ish minute point of this answers that question](https://www.youtube.com/watch?v=09uTFE_lkHQ) and [about the 3 minute point of this video](https://www.youtube.com/watch?v=22Jlmvm-Jt8)

Yeah....that thing is solid.

-Kevin
Yessir, we want it to fly more than once!

We are currently sitting around 110lbs dry. That should be around 170lbs with motors on the pad. 2500lbs of thrust puts us around 15:1 thrust to weight :D
We might be a little closer to mach than we thought. Haha

Braden
 
Well, good luck guys at Airfest. I was thinking about going, but I have this temp gig I am currently working for another month (until October), which has killed my plans to attend. Maybe next year. I should have stayed retired, but the extra bucks have allowed to spend as much as I like on some new kits (my Credit Card weeps). I'll drink a toast on Labor Day. "May the winds be calm, and your chute always deploy".
 
We are currently sitting around 110lbs dry. That should be around 170lbs with motors on the pad. 2500lbs of thrust puts us around 15:1 thrust to weight :D

With that weight, the C-9 will bring it down very nicely.

....are you sure that thrust:weight is sufficient? ;)

-Kevin
 
Well, good luck guys at Airfest. I was thinking about going, but I have this temp gig I am currently working for another month (until October), which has killed my plans to attend. Maybe next year. I should have stayed retired, but the extra bucks have allowed to spend as much as I like on some new kits (my Credit Card weeps). I'll drink a toast on Labor Day. "May the winds be calm, and your chute always deploy".
Thanks! And we’ll be back next year with at least one big project ;)
 
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