posted March 15, 2000 10:14 PM            

Ok the shells are pretty simple, they are 4.5 inches in diameter with a 4 inch internal. Giving them a .25 inch wall thickness. I know thats probably overdoing it... but i had that wall thickness readily available... and it was easier than machining solid stock. These have been threaded at the ends to accomidate the cap for them.. which holds the primer. As i said in the cannon post.. i gave them a rebated "rimless" design. The rear of the shell is only 3.5 inches in diameter, and has a .5 inch wide groove cut into it, .5 inches deep. This is also a bit excessive, but makes it a hell of a lot easier to extract the spent shell. By the way... i DO intend to reload these. Too much work in them to toss them after each shot
So far i only have made two different shels for this. One type is the flechette round i mentioned earlier, the other is a buckshot round. The rounds both use a pvc "sabot" with ..hmm... hard to describe... but its basically a cardboard spacer that is split in two, and glued to the two halves of the sabot. Thats so far the best i could come up with to keep the shot in place. The sabot's are only kept in place by how tight they fit into the shell (no crimp to hold them in). All i do is add a bit of glue to the outside of the sabot (and let it dry) if its too loose. I ram the sabot in with a press i made at work.. its pretty basic, but has a scale on the loading lever so i can see what kind of pressure i have on it. Right now i am loading the shells with 40 to 60 pounds of pressure. The powder, is 250 grains of winchester super, ball powder, ignited by a cci muskett primer. Both loads, buckshot and flechette, are 9 ounce loads.

Now for a question... does anyone think its worth the trouble to cast a single ball round for these? I mean.. a 400 caliber ball is a bit of overkill on ANY living beast, and for any uses such as blowing a hole through a wall with it... could simply be done with one of the rockets. Might be cool to fire one... but i don't really see any practical uses for it. Although a steel ball would deffinatly have some anti armour uses. Maybe a giant flechette round of tungsten would be usefull (for when i get attacked by tanks ). Dunno... let me know what you think.

Now for the rockets. I should say first, that i machined a barrel sleeve to fit the chamber of the cannon for when i switch from shells to rockets. Right now... they are NOT loaded with any explosives... as i am only testing them. i have the payload area's filled with sand so that i can see aproxamatly how they will fly when loaded. I havn't even designed the detonators for it yet... as thats a little ahead of matters. Now the majority of the body is made of aluminum. These rockets are 30 inches long, 4 inches in diameter. The nose cone however is made of steel. I am hoping that it'll add a bit more penetration to whatever these strike before detonation. To the tail... i've made a little jig to help me make these. I did decide to go with a folding fin design. They are still a pain in the ass to make... but i'm hoping its worth the trouble. The fins are made of pvc drain pipe. Mainly cause its easier to work with than the alluminum (and lighter). The fins are only pinned at the ends so they'll swivel, and the fins lock themselves open when the ends bottom out. We have springs in quantity at work of the type i needed... so luckily i didnt have to make these.
Now on to the engine... this is where i have some questions... I've casted some kno3 sugar engines for this. They are 3 inches in diameter, and 9 inches long. Anyone have a clue what amount of thrust they'll put out?

Now this is the wierd part of the rockets (and i have more questions). Since i have a mechanical firing mechanism on my cannon... i needed a way to fire the rockets the same way. This is what i came up with. Like the shells i made.. i made a shorter version of these to contain a powder charge and the primers. These simply fit in behind the rocket to ignite the motor. The primer fires into the loose powder, and i should get a pretty good fire blast out the flash hole into the rocket motor. These ignitors are also reuseable. The halves are threaded together, and only require a primer, a few grains of powder, and a paper card to keep the poweder in. This ignitor also serves to keep all the exhaust out of the action of the cannon, so it wont corrode or damage it.

Here now is another question (i know you all were just hoping i'd have more of these ) I had the idea of helping the rockets along with an initial blast to fire them out the barrel, and ignite them at the same time. A bit of a blast assisted launch. My question is... will a blast like this crack the engine grain and fuck everything up? Its just an idea... but i thought it would give me a heck of a lot more range, and hopefully a flatter trajectory. Anyways... its got a lot of possibilities.

Now guess what. MORE QUESTIONS

I know homemade explosives are not a good thing to be storing... but with the amount of time involved loading these things, it'd be nice to have them allready prepared. Does anyone know of something that i can make which has good storage ability? I wouldn't mind having to make the detonators ahead of time... but not the entire payload.

Now with that said... does anyone know what i should load them with?
What detonator, booster (if needed), and primary explosives should i use? Bear in mind... that i, like you... don't have a huge supply of money or chemicals, so some of the more exotic and expensive things are beyond me.

I think that about covers it. I know its a lot of questions... but if i even get an answer to one or two of them, it'll help.

Thanks guys.

BaDSeeD

posted March 16, 2000 02:37 AM            

If it can be done i'd make a solid ball. It would be great for longer range and shitloads cheaper than a rocket, even if it has no practical use (come on, how often IS this weapon going to have a practical use? : •) In other words, if its cool, do it...

As for rocket propellant i dont know, but as you know kno3 + sugar is quite brittle.. perhaps AN + rubber cement.. also the blackpowder + nitrocellulose bound with acetone (makeshift arsenal) is quite rubbery and wont crack, its also a prick to get to keep its shape (drys with gaps in it, perhaps ball powders would help this), also expensive.
ps. you didnt mention the type of nozel...

The "blast assisted launch" was brought up before, but rejected as suposedly the initial blast wouldnt allow the propellant to fully ignite therefor wouldnt immediately run under its own steam..
I recon the idea would work, but the barrel aint that long, so i dont know..

For the explosive, why not simply double base powder? unequaled stability in storage, low density to keep the weight down, low or high explosive & unless it being compared to ANFO or ANNM its also quite cheap.

For the detonator, i'd stay away from electrical means, unsafe and not reliable.
Using someone elses idea (FF's i think? someone correct me if its not) a cylindrical weight is placed behind a spring in the body of rocket, which upon impact under its own inertia compesses the spring and belts bown on a percussion cap fitted to a nipple, jetting the flame into a detonator, detonating the main charge.. using this method you could use a shaped charge and not be interfeared with by an ignitiator on the front of the rocket. also should be reliable and easy, bad side is it would probably be loaded and ready in storage..
For the booster.. tube packed with rifle primers maybe? at least it'll be somewhat safe to store but whether youll get a high order detonation with smokeless powder i dont know..

posted March 16, 2000 12:29 PM            

I thought about using a double base powder... but honestly... i've never been able to get it to detonate. Though i havn't tried very hard.

The ANFO or ANNM would be a good filler, as long as i mixed it before i was ready to fire. As long as its a powder... it shouldnt be to hard to load... and AN i know couldnt be much more stable to store. Also.. it's easy to make a large quantity with minimal time.

The only problem i've got with anfo and annm, is i havnt heard anything on this forum, or on mega's site really... that talks about reliable blasting caps for this.

Has anyone gotten complete detonation of their ANFO or ANNM? What did you use for your blasting cap?

BaDSeeD

posted March 16, 2000 06:20 PM            

I have struggled with tube launced rocket ignition before, and the solution I came up with is either electrice ignition. OR put a hollow tube half the diameter of the rocket nozzle around the percussion cap, and fill with a couple grams of NC. Have the cap in a small "cup" for lack of a better word, filled with an ounce or so of black powder.
That way the motor is sure to ignite and ignites the powder which blasts it out of the tube.

/| |\
| |
| |
| | | |
| | | |
|...,,,...|

,,,= primer, |=tube, and "cup" ...= bottom of cup / \ =nozzle

As for the motor, It will probably produce K class power, maybe more.
Make absoloutly sure you static test at least 2 motors before puting them in a rocket.

A few suggestions are make the motor smaller in diameter and longer. And make the entire rocket longer. For good stability you want to have a rocket at least 10-15 times as long as it is wide.

P.S.
Could you send me diagrams of how the fins work?

Catch 22

posted March 16, 2000 11:44 PM            

Thats exactly what i did..lol

I tried to describe it in the post.. but when the musket primer fires ... it is in a seperate piece.. it looks like a short version of one of my shells. it unscrews to where i pour in an amount of powder (loose), and when the primer fires.. its sends its fire into the powder.. which in turn the powder sends a LOT of fire into the nozzel of the rocket.
As i said... the shell has the added benefeit of stopping the exhaust from the rocket from screwing up the firing mechanism.

As for the schematics on the folding fins... i'll try and find some time (maybe this weekend... weather looks shitty) to do that.
I don't have a page i can upload them to, but i'll e-mail them to someone here if they don't mind posting them for me.

posted March 17, 2000 01:26 PM            

I don't have a drafting program for my pc. The best i can do is adobe photoshop 5.5
Its a pain in the ass to do mechanical drawings with adobe, as it wasn't designed for this. Can someone recomend a drafting program? Or better yet... give me a url to a warez site or freeware site that has a decent one?

Thanks.

posted March 17, 2000 11:26 PM            

Now i just have to figure out how the hell to use it.