CJ's "PUNISHER" build!

blackjack2564 said:

Before we forget [like I usually do] 2 must do's before going any further while glue cures:

1st slide nose cone coupler/av-bay into fin slot end of airframe, and use the slots to mark for 3 equal points around the coupler.
These will be transferred from coupler to vent band for altimeter breather hole & on NC for shear pin locations later.

View attachment 248526

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why did I never think of that?

blackjack2564 said:

FANTASTIC..... beyond all expectations of the design, this is a real performer ....oopps I mean...".PUNISHER".:dark:

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Are you saying this bird is a serious drag race Competitor, sure to Intimidate any future rocketeers who dare to challenge it? No extra bells and whistles or Gizmos here, this thing is designed for high performance!

daveyfire said:

Are you saying this bird is a serious drag race Competitor, sure to Intimidate any future rocketeers who dare to challenge it? No extra bells and whistles or Gizmos here, this thing is designed for high performance!

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Well ...........Gaaa......lee there Goober...........ShaZaammmmm! By Gosh I think you got!

Designed to down right "punish" performance, by ga...leee and spank the challenger's. [I suppose you probably recognize the fins, he optoptimized them folks]:y:

Ummm do I detect more than a few cliches here?

The 4in version is a down right Beastie..... of course one could leave out the guts and do a minimum with either.

By the way congrats on your new job title, I think [no..I know] you will do an outstanding job. Just hope all that work doesn't cut into your flying time too bad.

blackjack2564 said:

[I suppose you probably recognize the fins, he optoptimized them folks]

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I did recognize the fins. I commented on them earlier. I just can't see the full level of detail. Are the fins flat, as in same thickness except for bevels, or is there more diamond air foiling? This is exciting. I am in.

Going to paint mine in my trademark pink and get black decals that say "Pinkisher".

o1d_dude said:

Going to paint mine in my trademark pink and get black decals that say "Pinkisher".

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What come to mind instead of skulls...LOl

4kids49 said:

the fins flat, as in same thickness except for bevels, This is exciting. I am in.

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This....above

The bevel is on all sides. Inherently slippery design. Post # 106 has a good size pic of fin raw, just blow it up [click it]






Remember folks....the build continues, but back several posts where I reserved space for continuity in build.

"Back to the future"

daveyfire said:

Are you saying this bird is a serious drag race Competitor, sure to Intimidate any future rocketeers who dare to challenge it? No extra bells and whistles or Gizmos here, this thing is designed for high performance!

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Well, yes, but seriously don't get the switchband(?); especially if there is a step inside the nosecone--why suffer from an extra seam and 1" in length?

dixontj93060 said:

Well, yes, but seriously don't get the switchband(?); especially if there is a step inside the nosecone--why suffer from an extra seam and 1" in length?

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My guess (and that's all it is) is that the switch band is to make mounting switches easier.1" on this scale won't harm performance all that much IMHO, and if it does then you might as well go MD. But that's just me.

dixontj93060 said:

Well, yes, but seriously don't get the switchband(?); especially if there is a step inside the nosecone--why suffer from an extra seam and 1" in length?

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We thought about that.....actually for quite a while. And this is where it stands:

1. For those just getting into building fiberglass rockets & Dual Deploy [HED] the vent band keeps it simple & moves the sampling holes even further back, allows for standard placement of switches or twist and tape. With out it [vent band] where are you going to tape switch wire? Can't tape to NC or body tube, or that would prevent separation of parts at apogee or main.
It is designed as a simple, fun, easy to build and entry into HED [DD out of nose cone].

2. Those that want to go extreme can just toss it, use the half-hole method for switch/wire, no vents in NC & accelerometer based altimeters, magnetic switch or what ever floats the boat. Builders in this category are already versed in the finer dark arts of "extreme" building and can go it on their own. But then there are many just wanting something simple and fun.


So by supplying a vent band, it can be built as a sport flier or just toss it and go extreme with your own design, everyone is a winner this way and no one is left out. Either way an economical kit with a lot of versatility in the way it can be built.
Heck it's a great flier just using motor eject & you have a place for an altimeter to see how high it goes, with out sacrificing length or weight to a payload section.


It would make a heck of a sustainer in 2-stage ....short..compact all performance.

If you don't use the switchband, in this rocket how is the av-bay going to be held in place under acceleration? Unless you glue the av-bay into the nose, in which case you wouldn't be able to use the nose cone to store the main.

MarkH said:

If you don't use the switchband, in this rocket how is the av-bay going to be held in place under acceleration? Unless you glue the av-bay into the nose, in which case you wouldn't be able to use the nose cone to store the main.

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Shear pins.

I suppose, but with a K2000 you'd be looking at 60 gees and probably need 4-40 screws to be safe.

Yea, shear pins wont do the trick. Im wondering if there is a significant enough step built into the nosecone that it can positively stop the acceleration forces from jamming the coupler into the nosecone.

maxvelocity said:

Yea, shear pins wont do the trick. Im wondering if there is a significant enough step built into the nosecone that it can positively stop the acceleration forces from jamming the coupler into the nosecone.

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Yes the step runs full length forward....... the coupler simply cannot move forward,especially with a BP on it, there is nowhere for it to go. Look at the pic in post # 19...it's pretty obvious.

The NC is close to double the wall thickness from the step forward. The tip is even thicker with just a small hole in it to accept the phenolic point/tip. The last 3 inches where the coupler goes is actually same OD as airframe. This NC was well thought out for multiple uses, several changes were made before the final rendition cam to fruition.

So then a small slice of coupler tube 1/4" to 1/2" long could be epoxied in to the body tube for the coupler to rest on and you could eliminate the switch band and the extra seam.

Thought on foaming the fins?

maxvelocity said:

So then a small slice of coupler tube 1/4" to 1/2" long could be epoxied in to the body tube for the coupler to rest on and you could eliminate the switch band and the extra seam.

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????.... why do you need this, I don't follow. If you shear pin the cone onto coupler/shoulder it can't fall down into airframe & you must do this when putting main in the cone.

The cone is ejected at apogee and the main come out at lower altitude, no worries about the coupler being blasted back into the airframe, it's in open air.

Explain please, inquiring minds want to know.

Willie said:

Thought on foaming the fins?

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No advantage with foam on this build, there is not enough room between airframe and MM , barely 1/2 in. I want glue on this one, I'm injecting anyhow, so why inject foam.

Suppose you could.... but why?

blackjack2564 said:

????.... why do you need this, I don't follow. If you shear pin the cone onto coupler/shoulder it can't fall down into airframe & you must do this when putting main in the cone.

The cone is ejected at apogee and the main come out at lower altitude, no worries about the coupler being blasted back into the airframe, it's in open air.

Explain please, inquiring minds want to know.

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If you choose to not use the switch band then you are relying on the shear pins to hold the load of the coupler/sled/avionics/bulkplates/main chute/ shock cord and blast protector. Under the high loads from high G flights the shear pins will likely fail. If you epoxy a thin piece of coupler inside the top of the body tube right where the lower bulkplate will land after the lower edge of the nosecone lands on the top of the body tube then the body tube will hold everything in place. Since the nosecone has an internal shoulder you wont have to worry about the coupler jamming in the cone, another thing the switch band would prevent in say the usual filament wound cones with coupler used this way.

maxvelocity said:

If you choose to not use the switch band then you are relying on the shear pins to hold the load of the coupler/sled/avionics/bulkplates/main chute/ shock cord and blast protector. Under the high loads from high G flights the shear pins will likely fail. If you epoxy a thin piece of coupler inside the top of the body tube right where the lower bulkplate will land after the lower edge of the nosecone lands on the top of the body tube then the body tube will hold everything in place. Since the nosecone has an internal shoulder you wont have to worry about the coupler jamming in the cone, another thing the switch band would prevent in say the usual filament wound cones with coupler used this way.

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Got it! Thanks for the explanation, I missed that one.

blackjack2564 said:

No advantage with foam on this build, there is not enough room between airframe and MM , barely 1/2 in. I want glue on this one, I'm injecting anyhow, so why inject foam.

Suppose you could.... but why?

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Foam from the back end, without the motor retainer in place, sure seems easy. The question might be better stated as, "would foamed fins provide sufficient strength?"

maxvelocity said:

If you choose to not use the switch band then you are relying on the shear pins to hold the load of the coupler/sled/avionics/bulkplates/main chute/ shock cord and blast protector. Under the high loads from high G flights the shear pins will likely fail. If you epoxy a thin piece of coupler inside the top of the body tube right where the lower bulkplate will land after the lower edge of the nosecone lands on the top of the body tube then the body tube will hold everything in place. Since the nosecone has an internal shoulder you wont have to worry about the coupler jamming in the cone, another thing the switch band would prevent in say the usual filament wound cones with coupler used this way.

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If you use 3 shear pins on the NC and 2 on the airframe, that's 5 shear pins holding against G forces. That's 100 lbs at 20 lbs per shear pin, if forces are reasonably evenly distributed. Seems even at 60 Gs, it would be good enough for at least 24 ounces of AV bay.

Yeah that would work pinning the cone and the body to the av-bay. I'm not used to thinking of using nylon shear pins sort of as dual purpose rivets/shear pins.
The internal coupler band is a good idea too.

WoShuGui said:

If you use 3 shear pins on the NC and 2 on the airframe, that's 5 shear pins holding against G forces. That's 100 lbs at 20 lbs per shear pin, if forces are reasonably evenly distributed. Seems even at 60 Gs, it would be good enough for at least 24 ounces of AV bay.

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Where do you place the tracker in a head end deployment? Nose cone not available and short ebay. I don't like the approach of taping or typing to shock cord.

With limited space in the nose cone for a chute... do folks flip the Dual Deploy and have the drouge in the nose cone and main chute in the booster?

What wrong with taping tracker to shock cord I have never done any other way.

crossfire said:

What wrong with taping tracker to shock cord I have never done any other way.

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Protecting the tracker from shock of ejection charge and violent whipping of shock cord/parachute.

robbdm said:

Where do you place the tracker in a head end deployment? Nose cone not available and short ebay. I don't like the approach of taping or typing to shock cord.

With limited space in the nose cone for a chute... do folks flip the Dual Deploy and have the drouge in the nose cone and main chute in the booster?

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I fly many head end deployments rockets( smallest is 3.0 diameter) and I still tape my tracker to the shock cord. I tape it as far down as I can on the Drogue side. I put a nomex blanket in front of the charge well and then the drogue. I have never had a problem doing this. I have found that I put the main on a piece of separate short cord about 3 feet to avoid a redundant charge from getting to my main chute.

I haven't flipped my drogue to inside of nose cone. I also feel it is important to use the drogue chute in head end deployment.

robbdm said:

Protecting the tracker from shock of ejection charge and violent whipping of shock cord/parachute.

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Over 100+ flights with properly taped to cord (meaning the correct tape and the correct amount), not a single "problem"

Wow, this is a tough crowd....... that's great!

Ya'll are building this thing in your heads, trying to figure out where you would put your "normal" flying gear with out actually having hands on yet.

Exactly what we were going through and it took several days of shortening and lengthening stuff to figure out.
We can get everything in, that we normally would use in much larger, more spacious rockets. 2-altimeters, tracker, nomex on both ends, drugue...12in...25ft of cord in apogee side [ we fly around trees] 48in. main & 12 ft in nose. All 1/4 in. Kevlar.

All with a 54mm 6xl grain motor installed. Quik-links only on Av-bay sides of cords, knots to tie ends to Y-harness & NC loop.

I am sure there will be many, many other methods used and that's as it should be.


As far as Trackers go:

Before the build is done I will lay out the 2 ways I do it with both Marshal [Scout, 6in antenna ] and ComSpec [11.5 in antenna]
I have always taped tracker to shock cord, most often apogee side. Reason is...........when rocket separates at apogee the signal becomes very loud once outside the airframe, notifying me of successful deploy. Especially handy when flying at altitudes where you can't see.

I also have taped to Main shock cord when there wasn't room or any other way.

One must ALWAYS use electric tape [or spec the same] never masking as it will tear through even many layers. I tape the unit on & cover end to end unit and shock cord, but leave the antenna free.

For nine years now, it hasn't failed me. I have a few NC's with a place for trackers in them, they always worked great, especially when flying near water.
At Bong .....Twice now... I landed in ponds and the only thing visible was the NC & tracker bobbing on the surface.

I have seen so many different ways to install trackers, it never ceases's to amaze me.

Back to the punisher, there is enough room to get either type tracker I mentioned in both places, I have done it.

Of course room is tight, and it will depend on how much, & what size shock cord you use. For the NC how large a chute and what type, some 48's pack much smaller than others. The 2 sizes of tracker I use pretty much mimic most other units out there, so that should not be a problem.

There are a lot of 54 minimum's out there with everything crammed in, and this is like a cavern compared to them.:wink:

just a quick question cj is there enough motor tube to slide it down a bit and put a tailcone retainer on ? That would look sweet !