Multi-Staging with clusters

[Mike]

Is it generally considered safe to have multi-stage models with a clustered lower stage? I'm talking about low power Estes motors, probably a cluster of about 3 D's.

How about clustered lower stage to clustered sustainer?

Thanks

 

[astronboy]

As Frankenstein said:

"Clustered booster to single motor sustainer: GOOD!!

Clustered booster to clustered sustainer: BAD!!"

I have attempted the second scenario in the past. It is very iffy at best.

 

[vjp]

Originally posted by astronboy
As Frankenstein said:

"Clustered booster to single motor sustainer: GOOD!!

Clustered booster to clustered sustainer: BAD!!"

I have attempted the second scenario in the past. It is very iffy at best.

What about single to clustered, or clustered to single? Same deal?

 

[vjp]

Originally posted by vjp
What about single to clustered, or clustered to single? Same deal?

Duh, you answered half that. What about single to clustered? Has this ever been done?

 

[powderburner]

The difficulty of staging single-to-cluster is that you have deliver enough ignition 'stuff' to each upper stage nozzle to ensure a light-off. You probably do not get enough lower stage blow-through (hot gas and particles) to fill much volume and light too many motors, or else all the rest of us with single-to-single staging would be getting incinerated! So to make single-to-cluster work reliably, I am guessing you would have to design some sort of interstage ducting to control the blow-through, contain the pressure and not allow much expansion, split the flow, and re-direct it to all your upper stage nozzles. Most model rocket building materials are not going to stand up to much of that kind of abuse (temperature, pressure, erosive flow, etc).

I won't say it can't be done, but I have never seen (or heard of) anyone doing a single-to-cluster. We want to learn too, so if you pull this off, please let us hear about it!

 

[shockwaveriderz]

IF I was going to do a cluster-staged model ( and I'm not) and I wanted to ensure that the upperstage cluster ignited, I would probably use an electrical ignition timer to make sure the upper stage cluster ignited ....


I would also consider using say a non -zero delay in the lower stage so that it could eject a recovery system..as this lower stage would also contain the ignition timer/battery..
www.perfectflite.com has a micro timer, as does www.zitdt.com and of course there are others...do a search on timer in this forum and you will find numerous urls for ignition timer makers..

 

[SwingWing]

With cluster to cluster, single to cluster or APCP motors, electronic ignition would be necessary.
Cluster to single BP motors can be done. Be sure the rocket is stable with partial booster ignition. The worst failure mode would be a unstable rocket twisting about and the lighting the upper stage and stabilizing into a powered lawndart.

I think someone here did a DW CHAD dropstaged cluster.

 

[n3tjm]

Originally posted by SwingWing
I think someone here did a DW CHAD dropstaged cluster.

That was me . Worked Great. The booster motors were from the ame batch and same back, so their variance should not be off by to much.

 

[Mike]

Originally posted by SwingWing
Be sure the rocket is stable with partial booster ignition.

Hmmm, thanks guys, how can I work out if it will be stable?

 

[arthur dent]

I've been toying with the idea of cluster to cluster staging,but im now just thinking about cluster to single stage.when you say "partial booster ignition" do you mean not all the motors igniting???

 

[Mike]

Yes, such that on the clustered booster stage not all of the motors are burning.

 

[eugenefl]

Since we're on the subject of BP staging:

Here's an idea for ya - Jason (jetra2) recently built and flew a Terrier/Sandhawk rocket. It featured 3x18mm MMTs in the Terrier booster and a 24mm central motor in the Sandhawk. It flew successfully for the first time 2 weekends ago on 2 C6-0s and 1 C6-7 in the Terrier booster (C6-7 for Terrier chute ejection) and a C11-5 in the Sandhawk. All I can say is WOW. (BTW, this rocket features what is known as gap-staging.) I've never seen a gap-staged rocket fly before and needless to say, I was quite skeptical. I think Jason was too. I must say that this is no easy feat. I will hopefully someday do something as ambitious as this. See attached liftoff shot. Congrats Jason.

 

[SwingWing]

Originally posted by Mike
Hmmm, thanks guys, how can I work out if it will be stable?

The usual suspects, Rocsim or VCP or spacecad. Or build a long, tall rocket with big fins and good stability margin. Big booster fins.

I just recently built a cluster to single variant of the Deuces Wild that uses gap staging and a stuffer tube.
As Eugene says, it is fun to fly!

 

[powderburner]

Now I'm gonna have to order another DW

Darn the luck

 

[Silverleaf]

I realize this is an older thread..but:

The Estes Comanche D was my first 3 stage rocket - having launched it the first time as a single stage, then adding the second stage - both times perfect launch. Then double-checked everything and put the 3rd stage together. Hit the button and waited, fist stage dropped off, second stage dropped off, and 3rd stage lit..then gone. I swear that rocket made it to the moon. Lost it, then 4 weeks later was walking through the woods searching for a Sandhawk, and lo and behold, my Cherokee was laying on a pile of dried grass, in perfect shape - 3 miles away from the launch site.

The moral - have a gigantic field, and a large streamer for recovery. 8)

 

[Nite Builder]

Mike:
Sorry if I appear to be beating a dead horse here, however I thought I would share some of my experiences on the subject of clustered staging. As mentioned, clustered to single--good, single to clustered? At best, difficult. But Like Powderburner said, not saying it can't be done, just never seen or heard of anyone doing it.

I just recently launched my "Orbit" 5-stage rocket. Motors consisted of, (2)D12-0's to D12-0 to D12-0 to D12-0 to C6-7. All motors were "gapped" and "vented". Biggest problem multi-stage rockets have is not enough venting. The sustainer motor tends to "pop" off before actually being ignited due to extreme pressure. Anyways, I think I got about 5000 feet.
I think the luckiest thing that ever happened to me when it comes to rocketry is the fact that I got everything back -------Good Luck

 

[nomopbo]

I know this is an extremely old thread, but I'm glad it's here! A Multi-stage cluster is my next objective.

And the "cluster to single, GOOD" comment is simple, yet very good advice.

I'll let you know how it goes!

 

[Karl]

CHAD staging would work if all of the booster motors are taped to the sustainer motors. All of the motors have to light at excactly the same time note.
-Karl

 

[hokkyokusei]

The old MIRV Gryphon by Seattle Rocket Works (and laterly Lawndart Rocketry IIRC) had four motors in the booster and four motors in the "sustainer", but actually there were four sustainers, one motor in each. It was a challange to get them all to light, but it was certainly possible, and a fun flight ensued. I did a semi upscale once using 18mm mortors (but only in clusters of three).

 

[adrian]

Clustered upper stage: all those motors are going to be heavy. The lower stage had better be powerful enough to lift them! To ignite them, I'd probably put a piece of Quickmatch in each motor, tape the ends together, then run another piece of Quickmatch from there to the first stage.

Clustered booster: if the booster motors are sharing a single body tube and one of them doesn't ignite, the burning particles from the ones which did might bounce back and light it from the front. I speak from experience. Also, such a booster is likely to be heavy, so think about having one or more motors with delay and ejection charges to deploy a recovery device.

MIRV Gryphon: a very cool rocket, and I was the first person in the UK to own one. What's the minimum angle between the fins of a two-fin rocket like the sustainer of the Gryphon? Because I've had an insane idea, MIRV Gatling, like MIRV Gryphon only with 6 tubes instead of 4...

 

[hokkyokusei]

Originally posted by adrian
MIRV Gryphon: a very cool rocket, and I was the first person in the UK to own one. What's the minimum angle between the fins of a two-fin rocket like the sustainer of the Gryphon? Because I've had an insane idea, MIRV Gatling, like MIRV Gryphon only with 6 tubes instead of 4...

Hmmm. If it's a MIRV gatling, you might want to consider spin stabilisation. maybe spin the booster a bit and them get the upper stages to spin also. Might help their two-fin stability.

I'll look out for that at the IRW2004 , shall I

 

[Micromeister]

Guy's I really to hate repeating stuff over and over, but this is a very important technique. clusted to clusted motors is a very tricky operation in small non electionic equipped MODEL or LRM models. Without electronics only BP motor should be considered.

Because of the slighly different amounts of BP in ALL motors, they will have a slightly different burn duration, EVEN Booster motors. couple this with slightly different ignition times, you can begin to see the potential for upper stage ignition problems. Here is another example where matching motors by initial weight is critical. with matched sets of motors it is possible to lessen not eliminate the upper stage ignition problems. I've not been at all impressed with adding Thermalite to the upper stage motors. again those differing burns make for some LOOPY flights. Normal magic tapeed stage ignition has proved the most reliable...If that word has any meaning at all in this discussion. two stages is it NO MORE the timing gap makes more impractical. I've had exceptional luck with 2 staged clustes due to the system I use, HD relay ignition, HI amphr battery at the launcher, My own igniters or hand selected Estes igniters that have been tested before and after insertion in the motors. and as i mentioned earlier matching booster motors as closely as possible by weight. I only use one of my H/D relay launch systems with Proven Cluster ignition performace.

Someone mentioned the Gryphon, I very nice take off on a VERY old theme model called the Tri-AD, a 7 motor 3 2 staged model and core vehicle designs for a very old 4 event contest called Quadrant. I've convered the design to use 13mm motors in leu of the 18mm short motors used in the original. With a B6-6 or C6-7 core motor and 3 sets of A10-0T/A10-3T outer staged birds when the 3 upper stages seperate their tails look alot like the Blue Angle's "Bomb Burst" manuver..very kewl at demos

Can we build multi motor multi staged models...Sure. Will they survive more than a single flight..depends on how much attention is paid to all the LIttle things.

 

[nomopbo]

Micromister,
You are a wealth of information and a real asset to this forum. I swear there isn't anything you haven't done, and don't have a well laid out photo to prove it! (and you don't come across as a know it all, just someone that has mucho experience)

I think I am going to start a new thread titled " What Micromister
hasn't done, or is working on, or maybe wants to do" and let you have at it!

Love your input!