28 replies to this topic

[castillareno]

Hi, friends of PYRO-FORUM. I write from Madrid (SPAIN). Sorry for my bad english. Now I am press comets which this composition ''TIGER TAIL KAMURO METEOR.'' I desire shoot every comet like aerial shell: inside a cardboard (pipe of carton).

The exact diameter of every comet is 25 mm.

Please, I want to know ideal length of every press comet, in order that everything languishes in the air and none falls down ignited to ground. Also I want to know the quantity (GRAMOS) ideally BLACK POWDER lift charge, inside of every cardboard (pipe of carton).

I wait urgently for yours response.

Sincere regards from Madrid (SPAIN), PYROTECHNICS FRIENDS!!!

Edited by castillareno, 06 April 2004 - 09:43 PM.

[thewildething]

Hi Castillareno,
Firstly I do not have any experience in any shell/comet type launching so someone else on the forum may be able to give you some numbers, but I do think that you need to test various lengths/weights of comet with various amounts of Black Powder (using dud comets of course!). You should know the burn time of your comet so you need enough black powder in your tube to keep it in the air for at least the twice the burn time, so there is no chance of it falling to Eatrh. What I would say overall is settle on a comet weight/length and try a dud with varying amounts of black powder, until you get the flight time or altitude you want. This is only what I think, other members may have a better way to solve this problem. Hope it helps you Castillareno, and remember safety is paramount.

Marcus.

Edited by thewildething, 07 April 2004 - 11:00 AM.

[Phoenix]

I suggest you make the comet about 35mm long, and do not wrap it in paper. To start with, I would use about 2.5g of good black powder, and adjust this amount to get the result you like best. 2.5g should be enough that it will not fall to the ground. As thewildthing said, be careful when you test it, and you might want to fire some dummie shells that weigh the same as the comets, and are the same size, to get an idea of how they will function.

[castillareno]

Hello, friend Phoenix!!! It happy for me to return to speak with you.

The question: Then, every comet must have 35 mm of ideal length?

And the lift charge "ONLY" 2,5 grams?

I believe that is very few BP for lift charge, Phoenix.


I am going to write to you here my personal formula that I use in every comet/meteor PRESS wet with only water closet. Wait, Phoenix ............

This way you give me opinion. OK?

[castillareno]

tiger tail

Edited by castillareno, 09 April 2004 - 12:40 PM.

[Phoenix]

Your formula looks like it should be very good, but I do not have titanium or ferrotitanium so I can not make it. Thanks anyway though.

Are you going to paste the comet with paper, so that it can only burn from the bottom end? If you do, you will have to do tests and adjust the length to make them burn for the right time.

If you do not paste them, then they can burn from all surfaces, so the length does not affect burning time as much. You can make them as long you like, but if the comets are too long then they may be too heavy, or may break in half. If they are too short (less than 25mm) then they can rotate in the mortar and jam. 35mm would probably be OK though. I usually make comets and pumped stars so that the lenth is roughly about 1.5 times the diameter.

The amount of BP needed for the lift charge depends on how powerful the BP is. For my 25mm shells (which are about the same size as the comets) I use about 2g of BP. I think you would probably also need about 2g of commercial BP. I said 2.5g because it is best to start by having them go too high, and then reduce the amount until the comet just burns out at the top of the flight. Thay way, they don't land still burning. You will need to judge how much of your own BP you will need, and try it, then adjust the amount to get the height you want.

[castillareno]

Bitch

Edited by castillareno, 09 June 2005 - 10:10 AM.

[adamw]

Hello Castillareno.

If you paste paper around the dry comet star then this will make it burn for longer because only 1 burning surface is able to take fire (the other sides are protected by paper). It is best also to not use paper around the star because this may produce burning debris fallout.

For the height of the comet, I usually find that for smaller stars that it is usual to have the height the same as the diameter. So try 25 x 25.

The correct size, lift powder and other factors can only be discovered by testing the comet. If you still are using a lot of lift powder to get the comet high and it is still burning for a long time you can modify your star pump / machine to have a 'peg' that will produce a hole most of the way through the comet so it will burn faster:

Here is a picture of a slide for the pump with a 'peg'

[castillareno]

Thank you very much, adamw. I will have in bill your advices and you have been very nice showing the photo with the tool, to accelerate the combustion of the meteoro/cometa. I send a photo of them, drying off in the terrace of house. Measure of every comet/meteor= 25 mm diameter x 35 mm long. (I have followed Phoenix's instructions) Maybe they are too long, and they start to launch, for the force of BP lift, or maybe they fall down ignited...

As I say, in this moment they are drying off in the terrace of house. I have to try.

Question, adamw: How many grams of lift charge B.P you recommend to use me to launch?

Phoenix say 2 gramos / 2.5 gramos m?ximo lift charge, and measures comet/meteor=
25 x 30 mm even 25 x 35 mm.

P.D= I need your e-mail por send Photos. I do not know how to do it from here. Sorry.

Edited by castillareno, 08 April 2004 - 08:57 PM.

[Phoenix]

I didn't mean a _maximum_ of 2g, I just meant that is what I would use, of my BP, as a first try. I know from past experience that that is probably what I would need. However, I suggested you use 2.5g of good BP, as it is better to over lift the comet to start with so that it won't come down burning.

On the other hand, if you know that you need more of your BP than other sources (such as books) tell you that you would need of commercial BP, then you should base your first try on that. Just use whatever amount you think should be right, and test it somewhere it won't do any harm. If it burns out before it reaches the top of it's flight, use less. If it falls a long way back down to the ground, or lands still burning, then use more. Usually, you would want it to keep burning to the top of its flight, the just arc over and start to fall before going out.

[castillareno]

OK, friend PHOENIX.

[adamw]

Yes it is really better to try different sizes of BP lift charge and find the one that works with your comets. But if you use too much the star may not light well (blown out).

I have sent you a message through the forum with my e-mail address.

[BurlHorse]

Hey there all, Long time no post....

Anyway, the semi-rigid rule of thumb for lift charges is weight of object to be lifted, divided by 16, so for a 1 pound shell, divided by 16 equals one ounce, or 28 grams.

a 35x25MM Comet probably weighs in at about an ounce, or 28 grams, so........the lift would be about 1.75 grams I'd say Phoenix was pretty darn close!

So to you my Madridian friend, I say weigh your comet, take that number and divide it by 16, this will give you a good starting point.

This is not written in stone as there are variables to account for, such as the fit of the comet in the mortar, the grade and/or size of the BP, which by the way, I generally use 3fg to give the comet a good kick out of the mortar without disintegrating it as 4fg or 5 g would likely do. The Burn speed of Tiger tail is relatively slow when used in bigger stars or comets, so you would adjust accordingly.

Just a few thoughts, and as always, stay safe over there,

Regards,

Stay Green,

Bear

[castillareno]

I am grateful for your suggestions, BurlHorse

[BurlHorse]

You are most welcome!

Regards,
Stay Green!
Bear