10 replies to this topic

[pyrodude]

Hiya,
Looking at Stuarts Website i saw that he had an article on how to make rockets and was wondering how would you attach a payload to this type of rocket E.g Stars and also what size stick would i need for a big rocket with the tube being 6 millimeters thick and 3 1/2" in total diameter with a 3" ID and being 10" long as this is going to be one big rocket and how would i seal the top of it with it being so large.
Thanks for your help, Kyle

[Yugen-biki]

You will find some of your ansvers in this forum. The glue gun is a good help when puting on a cylindrical or round shell on a rocket.

[bernie]

Assuming you are building a BP rocket all that is necessary is too ram a goodly amount of clay on top. Slowly bore a hole just off to the side of center. Best if you thought to ram BP only in the last 1/2" so your drill won't churn around any metal causing a spark.

Where you gonna get this giant tooling?

A 6mm tube wall is not going to be thick enough.

I suggest you back up a little bit and work with smaller bore rockets for a while longer. It's insane to even imagine boring the core for such a large rocket. The proper tooling to create this monster is gonna cost you some SERIOUS money.

Edited by bernie, 08 February 2004 - 12:43 AM.

[Stuart]

PVA or glue gun. I no longer use wallpaper paste anymore as I recently bought a 2.5 litre tub of PVA. Wallpaper paste wont be strong enough I dont think.

Stuart

[willd]

i have tried adding a payload to a rocket by drilling a hole in the clay in the end of one of my rockets then filling the space in the end of my tube with loose blackpowder but for some reason the rocket got about five meteres then blew up i know i didnt drill more than a millimeter or two int the blackpowder. can anyone tell me what im doing wrong do i need a fuse or something

[Stuart]

If you don't pack your BP, then it will burn up through it very fast. Packing it will reduce burn speed due to there not being as many gaps between the particles.

Stuart

[StfuStuf]

I just thought of this...

A rocket that shoots out a shell from the top of it. So it basically becomes a flying mortar that shoots out a small shell. I think that would be pretty cool. Except I guess it would be really really heavy, but if it could work imagine how high you could get those shells!

[ash]

I dont think it would propel the shell much higher - or at least nowhere near as high as if the same powder charge was used to propel the shell from the gound. The detonation would push the "flying mortar" earthwards with an equal force as it pushes the shell upwards (ie Newtons 3rd law). Plus just think of the momentum the mortar tube would have when it hit earth again (not one you want to set off over the audience )

Having said that if you figure out a way to do it I wanna see!

[The_Djinn]

I stand to be corrected, but as far as I am aware of Newton?s law is based on the object being stationary. Hence if the rocket is travelling at 10 miles an hour and fires the shell, the rocket speed will be reduced by the equal amount of speed that the shell is fired at. If the shell is fired at a velocity of 10 miles an hour, the rocket would stall.
I think what you are trying to achieve is possible but it is going to boil down to some very close timing. As Ash has mentioned, should the shell be fired at apogee then the rocket will be propelled earthwards at an equal velocity of the shell moving forwards. I expect you would need to fire the shell prior to apogee then the rocket would stall and tumble back down as per normal.. but like I said it will need to be close timing. If you fire the shell to early whilst to motor is still burning it could change the direction of the rocket which could also have dire consequences should it be travelling back to earth with full thrust.

At the end of the day, the concept is not that different than that off a "shell of shell's" except that the mortar is replaced by the rocket as the means of getting the payload in the air.

Mark

Edited by The_Djinn, 18 March 2004 - 08:16 AM.

[Fluff]

I stand to be corrected, but as far as I am aware of Newton’s law is based on the object being stationary. Hence if the rocket is travelling at 10 miles an hour and fires the shell, the rocket speed will be reduced by the equal amount of speed that the shell is fired at.

You also have to factor in the relative masses of the rocket and the payload at the time of detonation of the separation charge. Now if the rocket fuel is all used up the rocket could be a lot lighter than the payload and acquire most of the separation speed (in a downward direction).

[willd]

stuart are you talking about the proppelant or the burst charge as the propelant was packed and surely you want loose blackpowder for it to explode. sorry if ive misenterprited you but would you please further explain