Two stage rocket - Stage connection question
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This is my 3" Wildman sustainer MMT. The conduit is 3/16" brake line.
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Thanks Rob, and Tim for the photos!
Does anyone know where the AV bay for that rocket was located? Fincan? Forward airframe? Nosecone?
I can see that the wires that were apparently used for the airstart didn't separate from the back of the rocket. I suspect that those would add a little drag, which I'm not worried about. However, if the AV bay isn't in the fincan portion of the airframe, how does one connect the Altimeter to the wire bundle, and allow it to separate upon deployment of the parachute? Some kind of cable cutter? Some kind of plug that allows the lines to be pulled out (yet holds it secure enough that it doesn't pull out during the boost phase)?
Thanks!
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woferry
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Curious what diameter that tube-fin cluster rocket is and the overall length. I was mulling over the exact same thing a few weeks ago, they're the two things I want to try next so at first I figured one rocket to kill two birds.
But I started to get concerned about the combined rear-end weight of both clustering and tube fins, in addition to the tube diameter I seemed to be heading toward (I was thinking central 54mm with 6 38mm's surrounding it, so that was heading towards at least a 6" tube). So I've started leaning towards just doing the tube-fin now and thinking about clustering later, but now you have me thinking about it again. Is the 'motor core' of that rocket actually removable, or are those latter pictures the assembly before it was glued in place?
BDB
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At this point in my planning for HPR two-stage, I am thinking motor deploy for the booster with a Chute Release. I'll probably do electronic deployment for the sustainer, but also use a Chute Release for pseudo-DD. The only issue is the tilt go/no-go decision. The Telemega is the flight computer of my dreams, but it isn't cheap. Is there any other altimeter that I could use?
Titan II
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blackjack2564
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The RRC3 3rd pyro channel,can be set to only fire sustainer if reaches altitude > [greater than] say 1400ft. or velocity > than say 600 ft/sec. You can set a coast delay also.
Pet timer default setting is fire after 1st stage motor burn out.[nothing to learn or change settings] That goes in interstage coupler. The second timer in it, [has 2] can be used as back-up/redundant with altimeter in booster. Saving space & money while learning.
It would happen like this:
1st stage motor burn out. Pet2 fires separation charge. After a 5 second coast, sustainer motor fires ONLY if it reaches altitude of 1400 ft. [ pick altitude after doing your sims] If something goes wonkers, it should happen before reaching what altitude you pick.
Booster coasts to apogee, altimeter/motor fires charge....Pet 2 fires back-up on cue.
If your motor choices are based on plenty of thrust, you should be flying straight, if not, you won't reach selected altitude going sideways & sustainer won't fire.
This solution only costs 75.00 +45.00 and is a great way to learn on smaller 2 stages. The Telemega is a fantastic unit, I have 1 myself, but requires a learning curve to familiarize yourself with it. At 400.00 I waited till I had a couple of 2-stage flights under my belt. It is a definite "must have" once you start flying large motors.
Pet timer default setting is fire after 1st stage motor burn out.[nothing to learn or change settings] That goes in interstage coupler. The second timer in it, [has 2] can be used as back-up/redundant with altimeter in booster. Saving space & money while learning.
It would happen like this:
1st stage motor burn out. Pet2 fires separation charge. After a 5 second coast, sustainer motor fires ONLY if it reaches altitude of 1400 ft. [ pick altitude after doing your sims] If something goes wonkers, it should happen before reaching what altitude you pick.
Booster coasts to apogee, altimeter/motor fires charge....Pet 2 fires back-up on cue.
If your motor choices are based on plenty of thrust, you should be flying straight, if not, you won't reach selected altitude going sideways & sustainer won't fire.
This solution only costs 75.00 +45.00 and is a great way to learn on smaller 2 stages. The Telemega is a fantastic unit, I have 1 myself, but requires a learning curve to familiarize yourself with it. At 400.00 I waited till I had a couple of 2-stage flights under my belt. It is a definite "must have" once you start flying large motors.
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Salvage-1
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Electronics in an AV bay half way up the rocket. I used JST connectors with the tiny little 'lock' tab shaved off, one good yank and they come apart.
The 'tail' of ignitor leads looks cool but doesnt affect the flight much. There is far too much momentum from the 12lb of Kraken.
Curious what diameter that tube-fin cluster rocket is and the overall length. I was mulling over the exact same thing a few weeks ago, they're the two things I want to try next so at first I figured one rocket to kill two birds.
The pics of the motor assembly are before it got glued (and screwed) in place.
Airframe is 4", which just allows 4x38mm motor mounts to be squished into the rear end.
For more of the story, check out the build thread
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Salvage-1
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RRC3 , Raven , etc. There are a few altimeters that have an additional line for airstarts, etc.
But.... once this happens..... Telemega is the next step.
You can see that one skidmark lit (DONT GROUNDSTART 2+ SKIDMARKS). Just after the second picture, the other skidmark lit. This was now at the 'bottom/lower' tube, and worked quite well with the tubefins and forward canard to keep the Kraken going horizontal. Then the two outboard Smokies lit. The Raven stated 400ft/sec horizontal.
Problem is, as soon as the last two motors burnt out, the nose dropped, at which point the computer shouted "APOGEE" then about 0.00001 seconds later "MAIN"
Obviously this needs a rebuild. Side note, Bluetube doesnt zipper, it unwraps.
Was that a cluster?
Salvage-1
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In all senses... yes.
Salvage-1
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SaturnV
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I care this issue tоо. The attachment of the second stage must be securely. Forces acting on its fins are large and the design must endure. On the other hand attachment does not have to be very hard to second stage can take off I have such an idea:
I have such an idea:
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BDB
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Not much yet. I flew the sustainer last month and I'm going to fly it again this weekend using a JLCR for pseudo-DD. I bought a 3" FG nosecone and a length of 54 mm coupler to use as the transition.
I'm pretty busy right now and I want to finish my L2 kit (BD Terrordactyl) before starting something else, so this will probably be one of my winter projects. I have two other MPR/HPR multistage builds on the drawing board, so next year will contain lots of two-stage flights.
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