How many stages???

It seems that my interest in rockets has led me to the multistage category of mid-power for a while now. I confess I have been stackin boosters ...as soon as I scratchbuild a new booster, I get it ready for yet another new adventure and we all get a kick out of guessing its new altitude. Well I'm up to 4 stages now(D12-0,D12-0,D12-0,C6-7 and everyone's telling me that my road has come to an end with this rocket. Actually they would be right if I used just one D12-0 to try and lift 4 stages,couldn't do it. Little do they know that I'm designing a 5th stage cluster of (3)D12-0's. It will require a bit more work than the previous boosters, but I am confident I can do it. Gotta prove them all wrong ya know.

Going to re-adjust CP & CG for a 5th stage..

Who's with me on this one??

I'm with ya and hope you have success with 5 stages. Very neat personal objective. Do you have any pictures to go with this post?

Nick

I think it's a GREAT idea! we (the rocketry community) need more inovation like this. Can't wait to see the outcome and hear about what you learn from your experiements.

Fortunately for you, you are not building a rocket in which you actually intend to fly in yourself whereas you might blindly call the project "ambitious." You are simply, well maybe not simply, but you are putting to practical use an idea in which through proper experimentation you may produce desirable results. In your defense, I say screw the naysayers! Just be safe and fly in a controlled environment and learn from the mistakes if any. What's at stake? A few motors, some twisted paper tube, and maybe a little heartache? It's worth it! Go for it! Do something unique and amaze yourself. Then come back here and amaze us too!

Oh yes, and I nearly forgot, document...document...document. (i.e. - PICTURES!)

be very careful:

The key is that there must be absolutely NO wind, or the thing will tip off. Once off vertical, gravity turn will take over.

I think 4 is about the limit for single D12's when you use conventional staging. However, using the rack rocket technique 6 or 7 have been reported. The largest rack I've heard of is 11 stages using 4 D12's for the bottom, and single D12's for the rest. For those interested in this technique, you can read about on the monocopters yahoo group. There is also an article on the Tripoli Pittsburg site https://www.tripoli-pgh.org/

Sounds like a cool project and I'll keep looking for updates!

There was a U.K. group a while (year?) back, that posted a video of a 9-stage Commanche-style clone. It was all done with mini (A10-0) motors. The advantage here is that they have such a short burn (<1 sec) that the total burn time is kept to a minimum, thereby reducing the 'gravity turn' probability factor.

Example 1 "A10": 9 times .85 sec = 7.65 seconds

Example 2 "D12": 9 times 1.65 sec = 14.85 seconds


....there's obviously a much greater chance of something going wrong in the second example.

Now, if you're gunning for MAX ALTITUDE, that's a different story; you can achieve much more with fewer, higher-power motors. But if your emphasis is just on the # of stages, don't overlook the minis (or even shorter burn 18mm or 24mm motors like B6-0's and C11-0's) as a way to achieve lots of stages while reducing probability of failure.

Yep the 9 stage attempt was a success, the same person recently tried 14 stages, all stages lit...just it was thrashing about on the floor.

don't let those NAR people hear about this

Just to note, the 9 and 14 stage models were in the UK so were operating under different safety codes.

Thrashing about on the floor does'nt sound to safe????

Originally posted by rstaff3
I think 4 is about the limit for single D12's when you use conventional staging. However, using the rack rocket technique 6 or 7 have been reported. The largest rack I've heard of is 11 stages using 4 D12's for the bottom, and single D12's for the rest. For those interested in this technique, you can read about on the monocopters yahoo group. There is also an article on the Tripoli Pittsburg site https://www.tripoli-pgh.org/

Sounds like a cool project and I'll keep looking for updates!

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I built one of these in 1971 with 4 stages of A3 motors. It flew really well and I never found it. The biggest one was a stack of 5 G160 Silver Streaks in 1993. These were so hot the glassed PML tube failed by the time the last motor burned and the fins blew off. I've got the G160 one on video somewhere.
I have always called this type of rocket unibody staged.

Despite listing the number of motors on my flight card (3 in a rocket designed for 4 on the first try), the RSO thought it was a single D12 model. I got two interesting comments out of that flight!

Originally posted by Rocketjunkie
The biggest one was a stack of 5 G160 Silver Streaks in 1993. These were so hot the glassed PML tube failed by the time the last motor burned and the fins blew off. I've got the G160 one on video somewhere.
I have always called this type of rocket unibody staged.

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Just out of curiosity, was the tube slotted to avoid the Krushnik effect? I bet that was a cool flight to watch! Please find that video.

Originally posted by rstaff3
Just out of curiosity, was the tube slotted to avoid the Krushnik effect? I bet that was a cool flight to watch! Please find that video.

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Yes, the tube was slotted. I'll see if I can find the video and convert it to a MPEG.

Sorry it has taken so long to get ya'll pics of the 4-stage Orbit. have had some trouble with my previous screen name(Prizzm242), so I will be posting for the time being as, "Minimag 54mm. As mentioned, the fifth stage booster will be a 3 motor D12-0 cluster with a specially designed internal manifold to more sufficiently direct the ejection flame. All boosters are vented as well. It may not look like much, but I am quite satisfied on how well this rocket performs.......................

Why is it that the rockets that work best are the rockets you never find time to paint?

nice, it looks like you took a bunch of boosters from other rockets

I've got the video of the 9 stage commanche. Is there any way I can put it on here?? It's 2,685KB

Eric

The best way is probably to give us a link to follow.

I did try and find it on the web but couldn't, thanks for tracking it down.

I checked my HD and lo and behold, I had saved it too.

I put it up (temporarily) at
https://members.verizon.net/vpearman/comanche9.mpg

Get it before Verizon chokes me off for using too much bandwidth!

wow, that is just amazing

In my earlier thread I mentioned that the I was starting work on a fifth stage cluster for the 4-stage Orbit. Well that work has begun( about finished actually) however the fifth stage will NOT house 3-D12-0"s, but rather 2-D12-0"s. Go ahead, call me a chicken, I can take it Seriously though, the reason behind decreasing 3 motors to 2 is this. All of my boosters are 4 fin, therefore assuming any additional boosters will be 4 fin as well. Ever try doing through-the-wall construction with 4 fins and only 3 motors internally.:kill: Not too easy! Unless ya'll got some ideas on how to attach 4 fins to 3 motor tubes????


Go ahead, make me build another one.....

yep, easy...

if your lower stage body tube is large enough (or even have some motor tube protrusion), got with a straight-3 rather than a triangle , like this:

OOO

jim

Yep,easy....If your lower stage body tube is large enough( or even have some motor tube protrusion) go with a straight-3 rather than a triangle, like this: OOO

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That would sure be a good idea if my BT was large enough, unfortunately the tube I'm using can only allow 2 motors across and 3 motors in the triangular design. I kinda want to keep aft drag down to a minimum or I would go with a larger(2.5 dia.) BT.
But I am much obliged for your idea. Actually I was thinking that in time to come I will variate different 1st stage boosters,eventually building one in the configuration you mentioned.........I'm still wondering if I should put "some" sort of tracking beeper in it....I know for a fact that this thing(provided all stages ignite) is going to go REAL high.
Future plans also include a final stage with an E9-8.

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powderburner..the NAR only suggests a maximun of 3 stages. Number of stages isn't even addressed in the safety code now.

I flew a 4 staged Astron Farside back in the stone age..early 70's, D12-0,D12-0,C6-0,C6-7 I got back the first and second stages, that was it! Dick is correct 4 stages will be it for single motor staging, your 3-D12 5th is a fine idea, I'd go with 4 D12's in a Bt-80 stage but that's just me. The clustered stage exhaust will need to be funneled into the next stage motor and vented to insure enough hot particles get into the next motor nozzle.

...sorry to dredge up an old thread just for this, but does anybody have a copy of the aforementioned video, "comanche9.mpg", that they may have saved off to their hard drive?

Originally posted by powderburner
three stages or you're out
don't let those NAR people hear about this

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Not true - there is no limit to stages in the NAR Safety codes - there is a Pink Book limit of three stages but that is for competition flights.

Why worry about thru the wall construction on the first stage? It is going to be the slowest portion of the flight due to the weight and properly constructed surface mounts can be very strong.

Before replying to these posts, remember this thread is almost 3 years old.... I re-opened it because I was hoping someone might have saved the video that I posted back then (COMANCHE9.MPG).