OK. I got more strange plans for you guys to look over

[Neil]

I was just thinking it would be cool to have a ring of Estes E9s surrounding 1 38MM motor mount. It just so happens that I could fit a 38MM motor mount, and 9 24MM motor mounts into one of those Staples mailing tubes I just got. so I made a sim for it... Tell me what ya think.

Wouldent it be cool to have a big red flame (AT redline) coming out of a ring of orange/white/whatever Estes flame?

Id have to figure out how to ignite them at the same time. I have seen enough of BP/APCP clusters to know they dont ignite at the same time (I almost got hit by a dual D12-3 and F21 cluster. It ended up going 20-30 feet above my head and into a hillside about half a mile away.... EEEEK!!!!). How does one do this? If only I had some Thermalite.... Where do you get that stuff, anyway? I bet it would be possible to rig up some kind of thermalite fuse to make the BP motors ignite a second or two after I press the button, to give the H or I (or, what the heck, a J ) time to ignite.

Where does one purchase thermalite? You need a LEUP, dont you?

The rocket could, of course, fly on just a single H, I or J.

This is what happens when I have too many mailing tubes! I start scheming evil schemes!

(or is this just another of my stupid ideas? )

 

[wwattles]

It *could* work, but when mixing the motor types you just have to be careful because the core-burning motors sometimes take longer to ignite - it might be better to boost it with the ring and then air-start the 38mm. The ring would have to have a pretty hefty ignition system and a couple large clip-whips to get all of them started.

WW

 

[gothique_97]

Or, start the core motor on the ground, airstarting the outboards; that'll give it a good, clean, solid boost off the ground with plenty of speed. If you can acquire it, use dfferent speeds of thermalite so that the motors will have a staggered airstart effect.

Sounds like a cool little project, though. I always wanted to try a motor mount configuration like that.

 

[Neil]

That still doesent solve the problem of GETTING thermalite...

Good idea, though. I would like them all to ignite semi-near the ground, so I could get a good pic of the ring of orange flame surrounding the big red flame.

 

[Ryan S.]

it would look cool but I would think the redline would drown out the orange flame. if they were smokey motors it would probably look cool. What will more likely happen is you will get a more smokey exaugst and you will see a little of the BP flame.

As for igniting them. I think I have heard of a method where you put an ignitor in the AP motor then put a flashpan underneath full of blackpowder. When the main ignites it will ignite the BP and then that will ignite all the BP motors. THis sounds good in theory, the main motor comes up first so chances are you get a good boost, but has anyone done it

Man neil you have millions of ideas. you better get to work I want to see some build pics

 

[Neil]

Sorry-all you get is Rocsim files untill spring . The workshop is too cold for building.

You wanna see my entire folder of rocsim files?

Yeah, I suppose it would kinda drown it out.... Maybe a blue thunder... That dont got no smoke (or not much, at least), and blue and orange dont exactly blend together... I357T??? possibly.

Interesting method... I have heard of twisting the Thermalite together just below the big nozzel, and when it starts up it lights the thermalite and gets the other motors going. That might work. I have never heard of using a flashpan to do that, though...

 

[Rocketjunkie]

Originally posted by Neil
That still doesent solve the problem of GETTING thermalite...

Performance Hobbies has Thermalite. LEUP required.

I use it all the time, the largest cluster a M2500 with 8 J350's air started.

 

[Neil]

J350s.... Lets do the math. Each J350 motor system (closures and case). 'bout $110. Thats... lets see... $880. Then, add the M2500 case... another $520. Thats $1,400 on cases ALONE. Then add the motor costs.... $540 for the M, call it $460 more or less for the Js, thats $1000 on the motors. Entire cost of motors for ONE FLIGHT:$2,400. Plus rocket: (call it about $300-$600 for the rocket) About $3,000. Lets say you start the Js halfway through the M burn.... That gets you about a 5 second motor burn.... Thats $480 per second of flight (only for the motors. Not including the rocket.) (also only counting the time the motors are burning).

Ill check performance hobbies later. Gotta take the dog out! thanks for telling me where to get it!

 

[Ryan S.]

yeah thermilite will work, you just put it under the nozzle and into the throats of the airstart motors...you need a LEUP though. The Thermilite lights and burns up into the outboards

 

[gothique_97]

Originally posted by Rocketjunkie
Performance Hobbies has Thermalite. LEUP required.

Back to square one for me...

 

[Neil]

leup leup leup... everything needs a leup...

Good news! we got an ATF office RIGHT IN PORTLAND! Howzat??? They just sent us our paperwork for the fingerprinting (a day or two after we asked for it, not bad!). they say that once we get our paperwork sent in we should have our LEUP within 90 days! 3 months.... Still, its better than the 6 months you guys said... Who knows if they will keep thier word, though.


So we should be able to purchase Thermalite ETC soon.

$60 for one spool? What is it? 30 meters? That ought to last me for the rest of my life... If I had a job I could just stock up on reload cases, a spool of thermalite, BP, APCP, and all that fun stuff. But it takes me a wicked long time to earn $60. and when I do, I want to spend it on motors, not a lifetimes supply of this or that. If only I had a job... Countin the days till I am 15/16 (?) and can get a job... But then I will get a lousy job at Shaws or whatever, and gripe about having to go to work every afternoon or whatever. But my dad says he might be able to get me work as an electritians apprentice. He is friends with several people who would take me. That wouldent be too bad. I sure as heck dont want to work at a Target all my life (no offence, doug, but I dont like the sounds of your "cart duty" during cold weater ). being an electritian looks like a good choice. I could go to trade school, move out west (either to Black Rock or New Zealand), stay single, keep a dog or two, and start up in EX motors! Sounds good to me! With all this housing boom, there must be a need for electritians out there! OK. I wont go into any more detail in my lifes plans.


I just had a nice romp outside with the dog... Its snowing outside (a lot. We already have several inches. Woulding want to be stuck on cart duty tonight, no siree!). Its Shannons first major snowstorm since she got here (possibly her first EVER snowstorm... Shes gonna have fun tommorow morning!). Shes sleepin in her crate now... Cuuuuuute!!!

Anyone else have snow????

 

[Rocketjunkie]

Originally posted by Neil
J350s.... Lets do the math.

Actually a *lot* cheaper.
Dr Rockets 98/10240 case - $300 (used).
8 *clone* 38/720 cases, $80 for material and an afternoon with a CNC lathe
Homemade propellant and consumable parts to fill all the cases $170. (The M was Smoky sam, the J's white.)

Here's a composite pic showing the burn:

 

[MDRocket]

Try this, you might have to do a test first though. Set up your core 38 mm on a timed ignition with the nozzel protected from the E motor ignition at launch. set a timer to light the 38 a split second after the initial launch, with a match dipped in pryogen (IE: Igniterman solution) And set the E motors off with a flash pan ignition. It is the way that a lot of cluster motors were launched in the old days. Your dad will have to help you with that.

It's worth a try.

Mike Dutch

 

[teflonrocketry1]

Neil,

You need to put in some more details on this design. On the 8 E's and I161 this rocket has about 1.25 calibers of stability. You might want to put centering rings, bulkheads, lugs, shock cord and electronics inside to see if the design is still stable when fully loaded. You get a real scary launch if the core doesn't ignite, try it out! Better use a 72 inch long launch guide.

Bruce S. Levison, NAR #69055

 

[Neil]

Oh, the rocket was just something I threw together. I needed something the right diameter and basic shape. It was more to test out the motor combos, not the rocket. If I actually decide to build it, yes, I will have a better design, dont worry

We have a 12 (or 16, I forget)' launch rail at our club

I dont quite get it.... Why have the timer on the core? wouldent you want to have the timer on the BP motors ?

 

[Austin]

Neil,

There are ways of speeding up how fast AP ignites, such as thermalite that was previously mentioned, or dipped ignitors. Yes, you are correct, if you want to ignite them together, the BP motors could be put on the timer to delay their ignition intil the AP central is up to pressure.

Carl

 

[LarryH]

Used to know of a pyrotechnics guy that sold thermalite broken down into it's two major components, didnt require an LEUP, nor even any HAZMAT fees, he was selling the stuff to shooters for use on exploding targets and for agricultural purposes(stump blowing, scaring crows, etc.)...... this of course was long before 9/1/01, dont know if he's still in business and dont know if he still sells it this way, I do know that even back then he was having problems with his local fire marshal trying to get him shut down.

 

[BlueNinja]

What diameter was this tube? I might try this with a 29mm instead of 38.

I like the idea of using the AP motor to light the flashpan.

You could rig it up so that you had a thermalite fuse going to all the BP motors, centered right under the 38mm nozzle so it would light them and have a delayed airstart. Or as someone said, use symmetrical arrangements of different therm fuses so it would have a staggered airstart. The first method would probably work good with a medium or long fuse, possibly so that they lit after the core burnt out. That would make for a cool (if stable) launch.

 

[Neil]

I already said that !

The tube is 4" ID, 4.217" OD (I think...). You dont really want a 29MM mount, I dont think. You need more oomph. Go with 38. You could, of course, downsize everything Then you could use something smaller.

 

[havoc821]

In theory, this might work. First you would have 2 seperate launch controllers. One hooked up to the 38mm, the other to the BP motors. Here is how it would go:

5...4...3...2...1 (press button for 38mm AP motor)....launch (press button for BP motors). Woosh!

This might work, never tried though. Never had a need to try. My biggest cluster was a C and 2 Bs in a modded Gemini DC.

 

[Neil]

Oh, that works? Cool! I always wonderd if you could put something in those pods on the DC.... Ill add that to my list of Estes kits I want to buy, reinforce, and modify so far I have "phoenix" and "Gemini DC". Any other ideas?


I still like the idea of having Thermalite below the nozzel. how does thermalite work? I have heard that you can strip off the outer stuff so it burns really fast. If so, you could get almost instinaneous ignition of the BP and AP motors. That would be good. See, the AP motor lights, shoots flame, lights thermalite, thermalite burns, hits BP motors, lights BP motors, FOOOOOOOOSH ( camera goes*click*). Interesting thought...

 

[BlueNinja]

Only problem with Havoc's idea is that the rocket would probably be going before you pushed the BP control.

 

[Neil]

Well, if you waited for the AP motor to start coming up to pressure, you could proabably get the timing right.

Orrrrrrr.... you could use a Pratt ECS2B to make the BP motors light at the press of the button. No wires going from ground to rocket, so you wouldent have to have perfect timing! Theres an idea!

OK. Heres my next plan. It is an un-glassed 4.217" OD rocket, 36" long tube, 3 triangular fins (Quite a reach from my normal 4 finned rockets with LOC Forte shaped fins, huh?), made of .25" ply, a foam cone and tailcone, 54MM motor mount (gonna give my adaptors some work...), and a PVC electronics bay. When I was looking at parts for a PVC rocket, I saw some threaded end caps. Now I was just thinking back to that, and now it seems like a pretty good idea to use one of those (and a piece of pipe) for an in-the-cone electronics bay.


I make way too many plans when I have too many tubes lying around....

 

[daveyfire]

I wish Pratt still made that unit... Missileworks has a similar one, the WRC², but it's $275. I think the best way to take care of the BP airstart would be with a G-Wiz, set for cluster launch detect. $80 and it'll pop all the igniters you want when equipped with 2x 9Vs. Gonna have to get me one of those!

 

[Neil]

Not a bad idea.... If only I had $80... I wonder if my dad wants to make a cluster rocket... IF he does, he could pay...