9 replies to this topic

[Aussie Pyro King]

Hello

I have finally achieved reliable core burning rockets and would like to have a parachute eject from the top. Is the parachute best made out of paper? and if so what sort?

I got this idea when I fired a commercial rocket. The rocket flew high and then ejected a parachute which slowly came to the ground with a very slow burning composition in a small tube attached to the parachute at the bottom. Luckily I found the parachute and tube but I have no idea how to fold the parachute and attach the strings. How do they get the parachute to come out evenly? Please help, thanks.

Jared

[Mortartube]

The best source that I can point you to is Lancaster's book which has a diagram of how to fold a parachute. The only additional piece of advice that I can give you is to sprinkle the parachute with talcum powder before you fold it. This keeps down friction and helps the chute to open more freely as it acts like a dry lubricant. I would suggest that you use thin cotton for the chute, the sort of material that handkerchiefs are made from, if not use tissue paper. Either way you will need to put bran or sawdust between the pyro bits in the rocket (the flare and blowing charge) and the parachute itself. This acts as a firewall to stop the chute catching fire when it's ejected. Also make sure the flare has a fairly heavy cardboard case as this helps the chute to fly properly, if it's too light the chute won't work (don't forget it gets lighter as the composition burns away). Have fun.

[Mortartube]

This might help, but obviously don't use plastic bin bags for your chute.

http://www.lnhs.org/hayhurst/rockets/

[Aussie Pyro King]

Thanks guys. I own a copy of Lancaster's book but it is being rebound at my local book binder because of a little accident with cousins.

Well I'll just have to wait

Jared

[adamw]

Sacrilige! Throttle the little **.......

If you fold the parachute into quarters so you end up with a square, then fold this square in half and then fold the corners into the centre so they meet to make a smaller rectangle, then wind the cord around this I think that will do the trick and it should open out no problems.

Be careful what colour the flares are and where you fire them (ie not near rivers, lakes, coastline, mountains etc) so they dont get mistaken for distress flares.

[The_Djinn]

Just to add to AdamW's words of caution.

I don?t recall if it is discussed in Lancasters book or Shimizu's, but there is reference to the fact that these devices have become less common both in the east as well as with many other pyro teams for various reasons.
One of the most noted ones being that if there is a breeze which may not always be evident at ground level, there is a chance for the device to travel a fair distance and come down somewhere and start a fire.

I recall these from when I was a kid, we all used to run after the parachutes and try collect them when they landed. They are also aesthetically pleasing as you get a prolonged effect in the sky as the suspended comp burns.
Until reading the article in whichever book it was I had practically forgotten about these but I must admit that after reading this link it is an item I will be adding to the ever extending list of things to try.. maybe with a glitter or willow type formula.

Mark

[Aussie Pyro King]

Yes I agree, there is a serious fire hazard. I must test the burn rate several times first so they are not still burning when they hit. I think i'll try and perfect the parachutes without a burning trail first so they don't come falling to the ground still burning when the parachute doesn't open.

[The_Djinn]

I expect it is more of an issue if you have a large amount of comp suspended. A small amount of comp deployed at higher altitudes should burn out long before it reaches the ground.. size of parachute would also be a variable as to how long it took the device to descend.
Shimizu say's Gampi Paper is best for the chute but has been replaced due to high price. He also goes on to say that thin cloth is sometimes used but falls at about twice the rate of a paper shute. Another tip in his book say's to crumple the paper to soften it.

Let us know how you get on as these are interesting devices and a little different from the normal devices people construct.

[bernie]

Model airplane hobbyist use a tough sort of paper to cover over wings etc. It won't tear as easily as normal paper. A wee bit expensive but no where near that of gampi.

[lord_dranack]

I got some today: 50p per approximatly A3 sheet (will use it for chinese fuse)