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Disappearing Act: Minimum-mass I1299 rocket

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CarVac

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Since I'm now feeling confident about using the body tube I made, and now that it and the nosecone and fin stock are currently post-curing, I decided to start a build thread for the rocket that I've dreamed of making ever since I found out about this motor: a minimum mass Aerotech I1299 Warp Nine rocket.

It's also to one-up all of the H410 min-d rockets that have been popping up like mushrooms lately: this currently simulates to accelerate at a peak of 231 G's, pushing the limits of even the 250G Raven I'm using for deployment.

I tend to scratch build my rockets, but this one is more completely scratch-built: the only parts I won't have made are a Blue Tube coupler for an AV-bay (it's hard to get good OD tolerances), the electronics, the parachute, and the motor.

disappearing_act.jpg
View attachment Disappearing_Act.ork Note: lotsa comments on the parts in the sim file, for those who are curious.

The nosecone I turned from balsa wood, for minimum mass. The body tube I laid up out of fiberglass in three separate steps: two layers of plain weave fiberglass uncompressed, then 5 or 6 layers of longitudinal unidirectional S-glass (it was hard to tell how many) vacuum bagged for minimum resin content, and then 3 more layers of plain weave. This was made with PTM&W 5712, the same high-temperature epoxy CCotner and I used/will use on Bare Necessities.

The fincan is a short section that I vacuum bagged a while back on a nylon mandrel; it's 3 layers of carbon/Kevlar twill, with carbon oriented circumferentially. This was laid up with Aeropoxy 2032/3660.

The fins are 1/16" G10 core, with one layer of 5.7 ounce carbon fiber twill on each side laid up with PTM&W 5712.

For electronics, I have a short section of Blue Tube 38mm coupler for an AV-bay. In it are nestled an Altus Metrum Telemini for tracking and a Featherweight Raven2 250G for deployment and data logging.

I'm using an 18" Spherachute as my main, bundled up with an Archetype cable cutter for dual deploy. The 1/8" Kevlar shock cord is anchored to the motor using the cut-off end of a dead (anodizing was dissolved off) Aerotech 29/180 case. A few holes drilled in it accommodate the shock cord, and it screws onto the forward closure of an Aerotech Electronic Forward Closure instead of the EFC electronics.


Photos will come later, since the post-curing cycle is running right now.


Either everyone will get whiplash watching this thing go, or nobody will even see it. It will leave a 4-foot tower at 225 feet per second, and it will break Mach at 85 feet above ground level. OpenRocket says it'll hit around 7300 feet, while RASAero claims about 10,000, but it's not gonna be the most aerodynamically clean rocket so I'm leaning towards believing OR on this one.
 

cjl

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This should be very interesting. I look forward to hearing how it turns out. I've wanted to do this since the I1299 came out, but I've never gotten around to it.
 

MasonH

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Oh I see how it is. -_-

Tood luck with the project!
 

JordanT

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Do you have a target date for your flight?
 

CarVac

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ROCStock, the coming Saturday. If I finish.
 

Rocketbuilder

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Very cool! You're insane. Still a cool project, though. :D
I'm glad to hear that you'll have tracking; I can't imagine finding a ~BT-60 sized rocket after a 7000+ ft flight without that sort of assistance.
Will it create an audible sonic boom? I don't know if you'd be able to hear it over the motor, but at on 85ft AGL it seems possible.
Good luck! :)
 

MasonH

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Looks like I have another record to beat...this should be fun!
 

New Ocean

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It would be fascinating to see what this motor could do at 100,000 feet!
 

kenstarr

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I built a similar project "Speed of Money". Originally titled Blackhawk 38. I had all intentions on blasting it away at Hellfire on an I1299 but alas, none of the vendors at the launch had that reload! They all said it was prone to CATO.... So I used my 38/480 case and threw in an I-225. It still went to almost 6000' and required a bit of riding around on the salt to find it! I'm still itching to test out the 1299 though. I just need to order it in advance!
 

CarVac

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I built a similar project "Speed of Money". Originally titled Blackhawk 38. I had all intentions on blasting it away at Hellfire on an I1299 but alas, none of the vendors at the launch had that reload! They all said it was prone to CATO.... So I used my 38/480 case and threw in an I-225. It still went to almost 6000' and required a bit of riding around on the salt to find it! I'm still itching to test out the 1299 though. I just need to order it in advance!
They are afraid of the propellant because a bunch of J1999's cato'd at LDRS a few years ago simultaneously. I contacted Aerotech about grain bonding and they said that the motor has never had a cato reported, but that grain bonding couldn't hurt.
 

CCotner

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We could probably work our new top end on Bare Necessities to contain Disappearing Act... *slaps self* *terrible idea* *that rocket has enough violence in its future as it is*
 
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New Ocean

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We could probably work our new top end on Bare Necessities to contain Disappearing Act... *slaps self* *terrible idea* *that rocket has enough violence in it's future as it is*
Just give it a frangible glass nosecone...
 

CCotner

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You mean, have the I1299 burst out of the top of the N5800 Alien-style?

I feel like that would disqualify us from the Tripoli record, just a little bit.
 

edwinshap1

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You mean, have the I1299 burst out of the top of the N5800 Alien-style?

I feel like that would disqualify us from the Tripoli record, just a little bit.
would be awesome to see, however.

Carlo I would check with Jack. IIRC he doesn't stock W9 anymore due to the issues he had with Aerotech regarding the J1999 cato's in 2010.
 

CarVac

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I just did; he can't get it from Aerotech in time, and Bay Area Rocketry isn't going to be in attendance, but they implied they can ship it to me in time for the launch.

Also, there's no way you would ever be able to see the I1299 from the ground when staged to (especially by an N5800 at 80-90k ft), since the motor makes no smoke.
 

cjl

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It would be fascinating to see what this motor could do at 100,000 feet!
Why?

It's got a decent Isp, sure, but it has an abysmal mass fraction due to the enormous core size. A lot of other motors would be a better choice, honestly.


As for the statements about reliability? I've flown a pair of I1299s, and I've seen several others, and I haven't seen a failure yet. The J1999 was problematic, yes, but I think some people are just extrapolating its poor record to all W9 motors, and I haven't seen any evidence that the other W9s are similarly unreliable.
 

New Ocean

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Why?

It's got a decent Isp, sure, but it has an abysmal mass fraction due to the enormous core size. A lot of other motors would be a better choice, honestly.
Oh this thread is about top acceleration, and without drag Id expect it to squeeze out another 50 gs or so. Maybe the burn is so short and violent that drag is insignificant?
 

weboide

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As for the statements about reliability? I've flown a pair of I1299s, and I've seen several others, and I haven't seen a failure yet. The J1999 was problematic, yes, but I think some people are just extrapolating its poor record to all W9 motors, and I haven't seen any evidence that the other W9s are similarly unreliable.
I haven't flown any I1299s (yet), but I've flown two H999s, 4 H669s, and two G339s, all without any issues.
 

cjl

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Oh this thread is about top acceleration, and without drag Id expect it to squeeze out another 50 gs or so. Maybe the burn is so short and violent that drag is insignificant?
I would expect that drag costs are maybe around 10G or so at the end of the burn - the easiest way to know for sure is simply to look at the data file after flight. Drag losses just before burnout will be similar to the deceleration due to drag just after burnout.
 

Rocketbuilder

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I hope so...
Well, I'm not exactly in much of a position to be condescending towards you. :wink:

OK, done hijacking this thread. Sorry for the sidetrack Carvac. :blush:

Back on topic, I noticed that you plan on using fiberglass for a lot of this bird, but CF for some of it. Is the FG really lighter, or is this just a practicality issue?
 

CarVac

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Back on topic, I noticed that you plan on using fiberglass for a lot of this bird, but CF for some of it. Is the FG really lighter, or is this just a practicality issue?
I used fiberglass because CF is harder to deal with in small sizes, and I needed radio transparency for tracking. Plus, my club has effectively infinite amounts of fiberglass we got for free.

In any case, I have an update: it's not gonna fly on an I1299 until next month, since I decided it's not worth 25 extra dollars for a single motor. I might try to L2 on it, though! I284 or summat to test, then J420 with a spacer. (so much for saving money)
 

bandman444

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I'v got a J354W (CTI 6G) motor if you are interested. Pm me, we could work out a deal I am sure. :)

Sounds awesome!
 

CarVac

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I'v got a J354W (CTI 6G) motor if you are interested. Pm me, we could work out a deal I am sure. :)

Sounds awesome!
Won't work unless you have a tapped forward closure, and also I don't have an extension tube available that'll extend long enough that's not wound paper and much larger OD. I'm planning on doing a J420: baby J Redline just like my L1 was a baby H redline, the H165. Totally different style rocket, though.
 

JordanT

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Oh this thread is about top acceleration, and without drag Id expect it to squeeze out another 50 gs or so. Maybe the burn is so short and violent that drag is insignificant?
I just printed out a model for a MD version using the 3 grain 24mm F240, simming to ~235Gs with a raven, but no tracker (don't own one...yet). The drag at burnout results in 70+Gs of negative acceleration (~mach 1.5). I suspect a similar result would be the case for Disappearing Act.
 

cjl

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I just printed out a model for a MD version using the 3 grain 24mm F240, simming to ~235Gs with a raven, but no tracker (don't own one...yet). The drag at burnout results in 70+Gs of negative acceleration (~mach 1.5). I suspect a similar result would be the case for Disappearing Act.
What kind of burnout mass are you looking at? In general, I'd expect a larger model (38mm rather than 24mm) to have a bit of a higher ballistic coefficient, so I wouldn't expect Disappearing Act to have quite that violent of a slowdown post burnout. I'm surprised it's that significant though - you must be simulating a fairly high drag and incredibly light rocket.
 
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