Multi rocket second stage

stealth6

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Hey all, brand new to the forum - pretty new to rocketry, sort of. Was into it as a kid WAY back in time (early 1800's as I recall), and just re-igniting the interest in my old age.

Have built and flown a few single stage rockets, some of my own extremely low-tech seat-of-the-pants design. Now I'm interested in multi-staging and I've got an idea in my head that I want to get some feedback on. What I have in mind is essentially a multi-rocket second stage. By this I mean the whole thing launches as a single craft from the pad, but during the second stage, it splits apart into two or three seperate rockets.

I can think of a few problems with this idea, but none that absolutely say, "major bad idea - do NOT go there". I've bounced around the net trying to find others that have explored this idea and found nothing. I figure either A)I'm not using the right phrases to search with, or B)it's such a bad idea that no one else has tried it and lived to tell the tale, or C)I'm a rocket science genius about to usher in a new era of technology and human achievement. (something tells me it's not "C").

So, whadda y'all think? Anyone done this? Is this really stupid to try? Anyone have tips or ideas or bits to share? Is this actually pretty common, or is it obvious this can't work because of ___x__?

Thanks in advance for your help/suggestions/guidance,
s6
 

bobkrech

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Hot Rod Nitro FireBall

Stage 1 - Airborne Fireball launch platform
Stage 2 x 6 - Hot Rod Rockets Nitros

Boris Katan of https://www.bpasa.com/index.htm and David Mackiernan of https://www.hotrodrocketshop.com/HotrodHome.html


LDRS28-082998b_small.jpg


https://www.bpasa.com/hrnf.htm

Bob
 

stealth6

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Excellent - thanks.

My idea is somewhere in between these - construction more like the Fireball but simpler inter-stage ignition like the MIRV Gryphon. hmmmmmm.

I can totally see, and would expect, some of the problems they had with the various Fireball attempts. Specifically, the sustainer stage rockets either not igniting, or being blown off trajectory at their ignition (or lack of) and heading directions other than up. All the info on the bpasa webpage is great - lots to learn from there.

As to the MIRV Gryphon, I'm pretty skeptical about the two fin design/setup on the sustainer rockets. Anyone here ever flown anything like that? I like the clean design, but.......

s6
 

BEC

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Look at the just-released Estes MIRV. This, too, is a single booster that then separates into three separate sustainer rockets.
 

stealth6

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Missed that Estes MIRV (thanks for the heads up). Yep, that's what I'm talking about. At least this verifies to me that it is a sane concept.

I can't tell much from the Estes website on how their configuration actually works. There seems to be only a single view picture, and it is actually kinda confusing. How are the fins actually setup on the sustainer stages?

I like the idea of a single motor for the booster stage. Simple.....wonder how well it works?

Mayhaps I oughtta just get one of these kits first rather than flail with my own experiments to start.

then again, maybe not.....

d6
 

adrian

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As to the MIRV Gryphon, I'm pretty skeptical about the two fin design/setup on the sustainer rockets. Anyone here ever flown anything like that?
I've flown the MIRV Gryphon and it does work. When the A10-0T went out of production, I built my own MIRV Gatling with a cluster of six 18mm booster motors each staging a separate, more conventional looking 13mm sustainer. That worked as well, once. It had the same problem as the MIRV Gryphon in that it sent a bunch of small rockets up to some height and then scattered them. Only one of the sustainers was ever found, and that was some weeks later. :D
 

stealth6

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Ok, I'm a bit farther down the road with this idea, and I'm actually getting somewhere - at least in sense of "putting pencil to paper" and doing some calculations.

It's interesting the timing of this . Just a couple months ago, I had absolutely no clue or idea of what was happening in the model rocket world. I didn't know this forum existed; I hadn't even seen a rocket launch in probably 30 years. For some reason the idea of rockets just popped into my head and I started to get real interested in them. So I just jumped right in, and along the way found you folks. And then this particular idea came to me and, coincidentally - as has been previously noted - the Estes MIRV just came out. In the last couple of weeks there have been a couple of threads started about it on this forum, and with them some more good info for me. In particular are a couple of other examples of folks doing, or having done, something similiar.

So, I downloaded the RockSim demo and jumped right in "designing" my rocket. I'm absolutely learning on the fly, and I'm sure I'm going about it the wrong way in at least a few areas, but I'm having fun just the same. I fully realize that I'm a complete noob at this and some folks must see me as some outsider bungling along with no clue. I appreciate it that no one has treated me this way so far.

I'm not sure what I'm trying to do CAN be done using RockSim. There are two issues it seems:
The first is that my "booster" is actually the main rocket and it has a nose cone - I can't seem to add a cone to a booster stage in RockSim; it doesn't give me that option.
The second issue is that my "second stage" is in fact three seperate rockets. Again, RockSim doesn't seem to allow me to do this.

So.......in the meantime I went ahead and designed this (in RockSim) as a single stage rocket, just to see if the whole thing would actually launch and be stable at least for the first stage. What I did was just created it as a single rocket with three outboard "pods" that do NOT detach as second stages. Where the sustainer motors would be, I simply put in generic "mass objects" with the weight of the intended motors plugged in. This way I could see how stable and under/overpowered the whole package might be at least to launch off the pad. It seems to work fine at least as a simulation.

For the time being this is all just an idea and theorizing. If I actually start to physically build this thing, I'll post some bits about it here. And of course, if I ever get to launching it, I'll report the results.

s6
 

stealth6

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Bump and update.

Well, after an (obviously) long time, I finally got around to some actually flying with this idea. I've actually spent quite a bit of time designing/studying/sim-testing this, but until now have not been able to actually physically try it out. So I decided to build an extremely crude mini version of this thing just to see if it would work. I mean REALLY crude - taped on cardboard fins, mismatched cones, garbage bag chute/streamers, junk box parts, etc. I just wanted to see if this would work without investing a lot of time/money into something that just fizzled or blew out of site and was lost. I also used (mostly) mini motors to keep the cost down.

Today I finally had a chance to put it into the air.


And.................. IT WORKED!
PERFECTLY!!

I flew it twice and both times it did exactly as I was hoping (expecting?) it would. The main rocket (which is technically the booster) had a B6-4 in the center and three pods with A10-0Ts in them. The three secondary/sustainers each ignited off the A10s and then flew on 1/2A3-4s. They all staged perfectly, igniting simultaneously and flying straight up, clearing the main/booster before it ejected it's nose/chute. Being tiny, they all briefly went just barely out of sight, but soon appeared together descending on bright streamers. All three sustainers landed very close together both times.

I'm psyched. Quite honestly, I was half expecting problems similiar to what happened with the Nitro/Fireball (sustainers blowing off and/or failing to ignite, sustainers taking off in random directions, etc.), but I had no issues. Both tests were as close to perfect flights as I could have hoped.

So, now on to the "real thing". Now I'm going to build this the right way. It will be upscaled from this, but still in the realm of low power/hobby. The motors will be a 24mm D12, three 18mm B6s, and staging to three 18mm A8s. The main/booster will be a little over two feet long, 2.6" diameter, and the launch pad mass will be around 22oz. I'm going to pay a lot more attention to detail and try to build something really nice. We'll see how it goes.

Once again, this will likely take a long time (this is a very part time/occasional thing for me), but I will at least post some pics when it's all done, and give a report when it flies. If I can manage to do so, I might even post some pics/details along the way as a sort-of build thread.

til then.....s6
 

hornet driver

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Go for it . Would like to see pics of the little test bird.Sounds like a very cool build.
 

paul.nortness

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Hey all, brand new to the forum - pretty new to rocketry, sort of. Was into it as a kid WAY back in time (early 1800's as I recall), and just re-igniting the interest in my old age.

Wow....you are old!

Welcome back to rocketry. Have a blast!
 

stealth6

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Kurt Gugisberg's

Triple Trick of Disaster (It was not a disaster at all. It was very successful!)
An L-850 staging to three parallel sustainers on H123s



Dang.

That there's a bit more...........uh, ambitious than what I'm working on.

Sure is cool/impressive/fun-looking though.

s6
 

Rocket_Man

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Hot Rod Nitro FireBall

Stage 1 - Airborne Fireball launch platform
Stage 2 x 6 - Hot Rod Rockets Nitros

Boris Katan of https://www.bpasa.com/index.htm and David Mackiernan of https://www.hotrodrocketshop.com/HotrodHome.html


LDRS28-082998b_small.jpg


https://www.bpasa.com/hrnf.htm

Bob



Here is a picture of the Hot Rod Nitro FireBall that I really like. It shows one rocket pointing straight down AND IS LIT! There is another rocket coming to point straight down that is also lit. 2 rockets pointing straight down that are lit ??? !!!

Doesnt that violate every rule in the NAR book of rules ????


IMG_7261.jpg
 
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cjl

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Here is a picture of the Hot Rod Nitro FireBall that I really like. It shows one rocket pointing straight down AND IS LIT! There is another rocket coming to point straight down that is also lit. 2 rockets pointing straight down that are lit ??? !!!

Doesnt that violate every rule in the NAR book of rules ????

No, it doesn't violate the rules any more than any other unstable or otherwise failed flight would.
 

Wayco

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So, does anyone have the video from the camera taped to the Hot Rod Nitro fireball?
That would have to be wild!

I really like Kurt Gugisberg's Triple Trick of Disaster. Just wondering what he used to ignite the H-123's. That had to be an awesome launch!
 

stealth6

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Well, as promised, this was going to be a very slow moving project. I've been working on this very sporadically and making slow progress. But progress nonetheless, and I finally pretty much have a rocket (actually four of them).

Also, as promised, here are some pics - it's almost there and should fly soon.

I've still got some work to do before launching - some finish details, getting all the recovery bits in order, etc. - but it's mostly "finished". The biggest worry I have concerns nose weight. Somewhere along the line, I miscalculated. When I did a "final" re-check I found that I needed a LOT more nose weight than I planned on (had to add 6oz. of lead!). I should have made the fins much larger - oh well, it's still supposed to fly according to RockSim. In a way this might be better. As it stands with all that added weight, this thing is not going to set any altitude records. But in all honesty I'm not that concerned with it "punching a whole in the sky", and a Low&Slow flight might mean I actually recover the sustainers, which is ok by me.


I will post a report after I get a chance to fly this thing. I've got no way to take photos or video, but I'll be sure to submit a written account at the least. It may be a while, or it may be as soon as this weekend. We'll see.

til then, s6

3sus1.jpg

3sus2.jpg
 

HotRod Rockets

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Some one paged a crazed rocket mad man?:roll:

https://www.youtube.com/watch?v=d1NJg-D3Jng

That's Video on-board from LDRS.

Remember sports fans, that rocket flew multiple times...not a one hit wonder. Some with greater success than others.

It was very carefully planned and the ideas and performance tweeked over time.

Love that rocket you have there Stealth6! Reminds me of... oh ya... PSYCO-X
https://www.rocketryplanet.com/forums/showthread.php?t=6928&highlight=psyco-x
----
I think I'll have that ready for CMASS Amesbury in September. If that's o,k with Mr. Bob K. ? (fingers crossed)

It's a project on the back burner for a while. If you need any help there Stealth don't be afraid to ask.

.:D I don't think about it I, do it.

.

captianchaos1small.jpg

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stealth6

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Ahhhhh, what a good day.

Woke up this morning to clear skies, no wind, and the luxury of a rare semi-day off. Said to self, "today we fly!"

So, got up and immediately started getting my launch bits together to go out and finally fly this thing. Ran into a bit of a problem at first though - as I was loading the rocket into the van I noticed that I had forgotten to install a launch lug! Oops. No biggie - a quick mix of 5 minute epoxy, some semi crude scraping of paint, and I was good to go. Off to the launch site.

Launched a few smaller basic rockets to test the wind and such. It had picked up a small bit but posed to real problem. Adjusted the pad angle a bit and prepped the main attraction. Started off with smaller (A8-3s) motors in the sustainers (though I think from now on I'm going to refer to them as
"parasites" - thanks for the inspiration HotRod) as this was the first test. Wired it all up, checked and double checked, and was ready to launch.

5....4....3....2....1.......

......BEAUTIFUL!!! Perfect flight, just as I was trying/hoping/planning for. Nice lift off - slow enough to be dramatic, but fast enough to fly true. All three parasites ignited on cue, and flew straight up off the main rocket simultaneously. They stayed together in a nice little air started drag race, and popped their laundry together. All four rocket's recovery rigs worked as they should and everyone landed pretty close together. It really was beautiful.

So, let's do this again, yes? I took my time cleaning everything up, and prepped for a second attempt. Hit the launch button, and this time - well, let's just say "not so beautiful". It seems that one of the outboard boosters failed to ignite. So the whole thing comes off the rod and immediately goes horizontal. It pretty much flew straight sideways about 40 feet off the ground. The main rocket's chute opened about ten feet from the ground and of course had a pretty hard landing accordingly.
When I walked over to it, I found that one fin had popped and the whole rocket got a bit beat up. I continued on to where the two parasites landed, and found one of them had the streamer get caught up in the shock cord and it never deployed or came out of the airframe - so melted streamer/cord and another broken fin, as well as a bit of hard landing scraping.
So, a bit of damage, but all relatively minor. But that's what having super glue in my range box is for, right?! So, I patched things up, resigned myself to having some less-than-pretty repairs, and prepped for a third launch.

This time, I decided to go with B6-4s in the parasites. All fixed, all prepped, and wired - time for the third launch.

Third time's the charm as they say. This one was even better than the first. Simply perfect flight. Watching those sustainer/parasites take off together was so cool. Unfortunately the sun had risen in the sky, and with the added altitude, the three parasites headed for apogee right into the sun - so I lost them visually at first. But they soon appeared together coming down on shiny red streamers, and everything landed within about 100 feet of each other. As good a flight as I could hope for all told. So, with my motor supply depleted, and a couple of more than satisfying flights in the bag, I packed up and headed home.

Dang that was fun.



Anyone who is interested should really consider building something like this - it was a blast all the way around. I'll post my RockSim file and a few other flight/launch details in a little while for your use if you'd like.

s6
 

stealth6

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Ok, here's my RockSim file, and a bunch of other bits/details that might help anyone who wants to experiment down this path. I've named this thing the "Triple Parasitic". Some bits to consider:

* The main important thing to understand is that the rocket in the file IS NOT A TWO STAGE ROCKET! It is only a single stage, and is incomplete as to the final version of this project. Why? Because you can't actually build this in RockSim - it won't let you have multiple second stages, nor will it allow you to put a nose cone on the booster (which the Triple Parasitic essentially has). Still it was worth doing the RockSim in that it shows all the parts necessary for the build (and where they all go!), and it also allows you to at least sim the launch phase of the flight - which is important for checking overall stability, and for choosing appropriate booster motors.

* This is by no means THE way to go about this, it is simply the way that I did it. Please feel free to design/build/fly whatever you want - whether it is just loosely based on this, a direct copy, or a modified/improved version. Use this info for inspiration or basic concepts to further your own vision of how to go about this, or build it exactly as is - whatever works best for you.

* This is a pretty basic, standard design and construction. No ground breaking ideas or techniques at all. It's also a relatively easy build. The only thing I would strongly suggest is to make some sort of good fin alignment jig - it's pretty important that all the fins line up the way they should.

* The main booster (the D12) has a simple engine hook, but the other motors are friction fit. The smaller boosters have a rear engine block holding them in, and they are direct staged to the sustainer motors with cello tape. Again - basic standard Estes style two stage construction.

* In the RockSim file, I've put "mass objects" in the place where the sustainer motors would go, with the weight of an A8-3 motor. You don't want to actually "load" motors there for your launch sims (due to this being a single stage rocket as far as RockSim is concerned).

* The RockSim file has incorrect recovery details. For the actual rocket, I used a 24" nylon chute with a 9" Nomex blanket in the main rocket, and 2" mylar streamers with wadding in the sustainers. All worked well.

* As I mentioned before, I had to add far more nose weight to this than I wanted to - 6 ounces of lead! If you wanted to build a rocket "just like" mine, I would strongly suggest addressing at least that design element in your own build. You could make the main airframe longer, or probably better, make the fins larger/wider.

* I launched from a 3/16" rod on a standard PortaPad. Anything less would not be recommended. A more sturdy pad would definately be better.

* You will definately need a 12volt launcher to ensure all four motors ignite, and do so together. I used an Aerotech unit off my car battery, along with a homemade clip whip. I used both standard Estes igniters as well as Quest ones.

* Although I originally planned to use B6-0's for the outboard boosters, they would have been too weak and I'm not sure the timing of the second staging would have been optimal. I ended up using C6-0s and they were great. A8-3s or B6-4s were both fine for the "parasites" - anything more might mean you'd stand a good chance of losing them. (Remember that you will be trying to track FOUR rockets simultaneously!).

* Did I mention this was fun? It really is.

So, there it is. If any of y'all build something similiar or related, I'd love to hear about it and/or see it. Any feedback or ideas would also be fun to hear/read. Build one - fly it - and post it here.

* Oh, and one more thing - don't forget to install a launch lug (sheesh.)

s6

View attachment Triple Parasitic.rkt
 
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