Mine / Shell Combination.

[CrossOut]

Hey guys, id like to try making a couple of mine / shell combinations much like the Japanese star mines... i will be using a 4" ball shell lifted to a normal height.. but was wondering if anyone had insight on how to stack the mine in there with the shell if anyone can make a diagram that would be great..

 

Can i tape a small pouch of stars on top of the shell for the effect?

Do i need to use a full size lift cup for the stars?

etc

 

thanks in advance.

Edited December 11, 2012 by CrossOut

[dan999ification]

first you need a piston, at least one id thick corrugated card disks can de glued together, i tend to alternate the corrugations for extra strength and prefer card over solid pistons to help cushion the load, a central hole in the piston is enough to accept the leader and ignite a mine but for inserts i add four smaller holes around the centre one, since a ball shell is going in i would not fuse the centre hole but run the fuse along the wall of the sleeve.

Three or four turns of craft rolled then taped or glued make the sleeve, the sleeve must provide enough confinement for the shell to ignite before it leaves the tube so needs to be quite strong and survive being tied

Make lift bag and attatch the leader, i tape this to the piston, tie one end of the sleeve, and insert lift,leader,piston, add stars, add shell, tie the top off.

 

What stars will you use? Do you have an idea of the shells weight and how many stars for the mine you want and how much lift, it is critical to not overload the mortar on big mines.

 

Dan.

 

 

 

[Xtreme Pyro]

If you want a mine effect when the shell lifts I always just put them directly into the lift bag, but I believe I remember Seymour telling me you can also tape a baggie of stars on top of the shell as you suggested.

[dan999ification]

stars on top could damage the shell, stars in lift could slow it down or speed it up, getting a good amount of stars to good height will look better than a few falling off the shell or just falling out the gun either way the effect will look sparse and low due to the smaller amount of stars that can be used safely and the construction.

I try to avoid just bunging things in when i fire, is it a mine with a shell or a shell with some stars thrown around it? There is a few advantages to the extra work.

 

 

Dan.

Edited December 11, 2012 by dan999ification

[nater]

I just drop a handful of stars in the mortar after loading the shell.

[Mortartube]

A small bag of primed stars thrown on top of the shell has always worked and never caused any problems to anyone that I know. Just put in about the amount that you would put in if it was just a mine in that size of mortar.

[dan999ification]

i use 100-150g of stars for a 3inch mine, theres no way id put them on top of a shell but then again i never thought about using a bag of stars which would in effect stop them migrating around the shell,which is what worries me,duh.

To get the best presentation i still think it is important to put more effort in, the way i build them you can put almost any insert/s in there ( normally bombettes ) and that construction is key to getting the stars as high as possible to have the inserts break just above the stars apogee or burnout, i use larger than normal stars to help with height also.

I will try the bag of stars but it looks and feels so wrong, im quite passionate about mines as you can probably tell.

 

Dan.

[CrossOut]

Thanks for all the replies guys!

 

The effect im looking for is as XP described it, the mine effect when the shell is launched. i though about simply dumping a hand full of stars on top of the shell prior to launch but i was also worried about the shell being jammed.. for a hand full of stars or 2 this isn't really much if a problem as the gasses expanding around the shell would easily clear it out of the way of the shell.. second the force of the shell would easily crush any star in its way. I lost count of how many times ive seen a shell jammed stuck in a mortar due to the tube being warped or because of debris. naturally getting the shell out by had was always the worst idea so the general fix was jsut shoot the shell and it will clear its self.. so far that has worked 100% of the time. no detonations cause of a jammed shell yet.

 

however i believe that safer is better so i think the bag of stars method would probably be best assuming this method actually works.

 

any other suggestions / concerns i should have?

[dynomike1]

If a star hangs a shell coming out for 1 millisecond you can get ready to buy another tube. I guess you could have to see what i have seen to understand, What i have seen is Cannon barrels busted open with only 2oz of FG. over stuff like this. Its up to you, you might do it 1000 times and get away with it but don't let your guard down

[CrossOut]

Agreed it is a potential hazard.. however with a paper ball shell the shell is soft which will form around the star and in most cases the star would be crushed from said forces.. as you said its best to be safe.. the pouch method will be used.

[MrB]

I've had shells not getting the height they were supposed to, a single flowerpot, (could simply have been a defect in the shell) and lines/scratches in the mortar from dumping stars on top of the shell. Now-days i tend to add a lift-cup with the mine-content. Having the stars on top of the shell also gave me a slightly wider spread, Barely noticeable, but still. I prefer putting mines in really short tubes, or even just on top of a "wok".

B!

[dan999ification]

my colour shells will not crush, nor will my solvent bound stars they are like stones, the velocity of the shell protects it to some degree making it stronger ive seen em shot through plywood even the big ones dont collapse and should given the large soft centre and dimensions.

The risk of malfunction does not bother me really with good distance and 1 inch walled card mortars, wasting my work does.

Surely just placing the stars on top and relying on the lift gasses to centre them also means that they are floating in hot gasses and not actually being pushed by anything other than hot air, this in turn means low stars if true, the shell relys on its own weight the stars need help.

 

Small stars and energetic prime should be avoided in large mines,

time fuse can be adjusted to compensate for the poor height ( in comparison to the shell )

10 percent lift is enough for large mines with large stars and inserts or shells maybe too much in a four inch, built properly you could easily send over 750g up and would not need 10 percent.

I have video of mine lifts, my first few were pants....just bunging stars in the lift bag.

 

 

Dan.

[Mumbles]

...

The risk of malfunction does not bother me really with good distance and 1 inch walled card mortars, wasting my work does.

Surely just placing the stars on top and relying on the lift gasses to centre them also means that they are floating in hot gasses and not actually being pushed by anything other than hot air, this in turn means low stars if true, the shell relys on its own weight the stars need help.

...

 

What exactly do you think happens to a shell when it's being lifted? Magical elves kick it out of the mortar?

[dan999ification]

no, i thought it was the guy in the red suit and the pointy hat.

The lift gasses creeping around the shell before it leaves cant lift it but could well lift the stars, after pressure has built up enough to lift the shell the gasses are still escaping around it now do they go straight up and leave the stars alone or that and following the shape of the hemi lift the stars?

Because there is blowby the stars will be affected by it, which is fine the stars just wont go as high as they could if it was restricted.

A sabot in a smooth bore helps the shot build velocity increasing distance and concentrating the grouping by controlling the blowby that the load will be affected by, the same principle aplies here.

Mines without pistons spread the stars wider and lower than mines with them and in this situation i would want the stars to follow the shell up as high as possible.

Light stars may get lifted by the gasses and not build maximum velocity resulting in low stars

heavy stars may not be lifted by the blowby gasses and ride the shell building good velocity but possibly getting stuck

just the way i see it no elves, my mines are great check them out.

 

Dan.

[MrB]

I'm not entirely sure, but i think the reason for stars to cause issues is small, hard stars, and a fairly tight fit for the shell in the mortar. Regardless, i've only had a few issues, out of loads of shots like this, however, as i found it way easier to load, and fire the shell with the mine attached to the bottom, i've started doing that over dumping the "mine" in after the shell.

 

Dumping the stars in after works, at least most the time, and when it fails, it's rarely a spectacular fail. I've never had a shell roundtrip on me, or anything like that, from dumping a handful of stars on top of it.

B!

[Mortartube]

You have to exercise some common sense. Use fairly large fast burning pumped stars in a thin plastic bag and throw it on to of the shell. It produces an acceptable effect and is quick and simple to do. Much depends upon the amount of time that you have available to you.

[Pirotecnia]

Well, i'm using the method below.

 

 

Tonight i launched one like that... In my opinion, it works in a beautiful and efficient way.

[Seymour]

Pistons of various sorts are definitely a great addition for mines, and as said are critical to getting good and uniform height. A shell makes a great piston.

 

Stars above the piston/sabot are obviously a lot more effective than below it. Both work, but if you put the stars with the lift the mine is... a bit shit.

 

Loose stars jamming the shell in place is only a problem if you want to pull the shell out by hand. If you fire the shell, the lift gasses are going to move the stars out of the way before the shell has moved much at all. All those slow motion videos of shells being fired from transparent mortars demonstrate this.You may break one or two stars, but you certainly won't ruin the effect or add a level of danger.

 

If you are adding just a handful of stars, the shells lift alone is all good. If you are like me and want to stack the mortar half, or even all the way to the top, you might want some more, but like big multibreak shells, perhaps less extra than might be expected.

 

Tonight i launched one like that... In my opinion, it works in a beautiful and efficient way.

 

Beautiful and effective I agree. Efficient, I do not agree. There it twice as much work to your method as if you used the shell as a piston instead of that extra disk.

 

Light stars may get lifted by the gasses and not build maximum velocity resulting in low stars

 

Can be true.

 

heavy stars may not be lifted by the blowby gasses and ride the shell building good velocity but possibly getting stuck

 

Yeah... No. Not any star on earth. A neutron star perhaps.

 

The lift gasses creeping around the shell before it leaves cant lift it but could well lift the stars, after pressure has built up enough to lift the shell the gasses are still escaping around it now do they go straight up and leave the stars alone or that and following the shape of the hemi lift the stars?

 

Well, the gasses are going to follow some sort of pattern and curve around the shell in certain ways that I'm sure can be predicted. At the end of the day, whatever the exact route of the lift gasses, in normal situations you get fire everywhere, and anything primed lights anywhere in the mortar. Look at rising comets, sitting right at the top as sheltered from the lift as you can get.

 

Do you have an idea of the shells weight and how many stars for the mine you want and how much lift, it is critical to not overload the mortar on big mines.

 

With weak mortars this is true, and I won't deny that many commercial mortars are probably weak enough to be in this category. With suitable mortars though, overloading a big mine is when you cannot fit it all in the mortar due to literal lack of more volume.

 

Small stars and energetic prime should be avoided in large mines

 

Small stars, I completely disagree with. Energetic prime, I mostly disagree with. Sure, I could come up with some 'energetic primes' that fit the bill, but within the reasonable range of common primes, I don't think there is anything to be worried about.

 

Crumbly silver stars on the other hand... now they are a hazard.

 

CrossOut, have you seen Shimizus description and diagram of a Japanese type starmine? It's on page 267 of my 3rd edition copy of FAST.

 

Not one, but two full size shells are lowered straight on top of the lifting charge. 'Small flowers' are next loaded, appearing to take up about 1.5 X the ID in mortar length. Then what appears to be a similar volume of stars is placed on top, and the mortar is capped with the only card disk used in the set up, with only one ID of empty mortar at the top.

 

This is a star mine system that I approve of!

Edited January 1, 2013 by Seymour