29 replies to this topic

[robert johnson]

Is any body into rockets for payload or speed?

[Matt]

I originaly got into rockets cos its fun. About a month after i started i wanted to make them go faster and so i tried new propellants but meal powder beats them all and ive only been doing them for about half a year and my little engines are 9.5mm I.D and 3.5cm long travel to about 300-400 feet (only with a stick) and since ive got them performing well i have been putting payloads on them. I only actually started putting payloads on last weekend. they easily take up a 10 gram payload so i might up the size a bit for this weekend, see what happens.

-Matt

[Rhodri]

I made some small rockets a while ago with reasonable success - about 1 in 3 launched straight up. 1 exploded - I now know why - 1 shot off the wrong way.

Making sure I perfect these before any more launches!

Currently though, I'm trying to make some really good colour compositions. So far I've got a pinkish red and a weak green.

I know it's basic stuff but I'm making a traffic light!

Also looking into perfecting my Roman candles - need to apply some 'oommph' to the stars' colour though - so far I have a sort of orange ball with occasional white sparks. I do get quite good heights though.

[robert johnson]

At the momment I am able to get the Rockets up to about 400 feet and carry 200 gms of pyro, usually a 3" shell or some type of pyro payload. I use a Refined black powder with a few percent of balsa charcoal added into the initial mix which is made using the precipitation method the ratio of the powder is 75/15/10 a normal mix which gives the motor a reasonably long tail but with loads of power. The case's are 110 mm long with an id of 24.5 mm and a 6 mm wall thickness. these motors are quick and very attractive in flight. The knack is to have good reliabilty is too have good tooling and once you have the set up correct don't change it.

[Rhodri]

Wow! That's a big payload - would love to see one of those in action!

I too use BP for the engine and now understand why one of my first attempts exploded - the nozzle was too small and the BP was very fast Willow BP. I'm now using a different ratio for the BP which I find gives a reliable lift -> 65:20:15. I also add a 'smidgen' of icing sugar.

I haven't tried any payloads yet as I'm not 100% confident with my rockets but it is an aim.

I use a nail and dowel to create the centre part of the rocket. This works but I can imagine that Robert's comment on the right tools would make the manufacture easier.

To change the subject, any advice with colours? I use Ba2CO3 and Sr2CO3 with BP in varying 'bucket chemistry' ratios and don't have a ready access to ClO4's.

Thanks

[Pyromaster2003]

i made a very good rocket using a mix of 30 sodium chlorate:30 potassium nitrate:25 burnt timber:10 sulphur:5 aluminium powder(from tiranti). the rocket shot off the ground with great speed leaving i nice silver trail behind. it flew about 200 feet and then the nozzel hole got bigger and there wasn't any more power so it fell back to earth still burning. the rocket was 1.5 cm ID, 7 cm long.

[robert johnson]

Do you have access to Parlon,Red gum or good quality Pvc. Can you confirm that you do have carbonate colouring agents as I think you may have added a [2] in to your chemical nomenclature which I don't recognise.
Certainly with most colours and colouring agents you need a Chlorine donor for the colurs .A good example of this is a Barium Nitrate Formula that gives a good white but soon as a chlorine supply such as Parlon or Pvc is used you end up with a very good green.
I personally use magnesium in my red's Greens and White's although it is expensive for the correct grade it creates a absolutly splendid colour.
As far as Potassium Perchlorate goes all my formula's use Potassium Chlorate as this is easier to buy than the other.

[brocade]

Rob is quiet correct stars produced using mag formulas give far superior results to those produced using standard carbonates, nitrates & chlorates. However it generally costs more to make mag stars and they are notoriously difficult to work with as the correct grade of mag has to be selected and the binder chosen carefully ie you don't want to use water alchole and dextrin as usual as water applied to mag powder can cause it to heat up. Therefore for these reasons it is usefull to use general colour star formula's as they are cheaper, easier to use and give acceptable results especially when trying things out presented below is to red formula's that work well for me.

Potassium chlorate 70%
Strontium carbonate 15%
Red gum 10%
Dextrin 4%
Charcoal 1%

bind with 75% water 25% alchole

the above can be used as a pumped star or even better as a round star ever way this will require a 1mm prime of H3.

Red mag

Strontium nitrate 55%
PVC 7%
Parlon 10%
Magnesium 100 - 200 mesh 28%

These mag stars need to use a stepped prime ie roll stars to 8mm then take 75% mag mix 25% bp and roll to 8.5mm then 50% mag mix 50% bp roll to 9mm then 25% mag mix 75% bp roll to 9.5mm and finaly 100% bp to 10mm.

Bare in mind once you get the strontium carbonate star working it is worth pursuing the mag star as this gives a really bright red in the sky.

[robert johnson]

Mr Brocade I think we need to meet some time as your knowledge is quite impresive and factual. Also I like the fact that you talk pyro, Every year I usually have a few good displays around the country of high quality fireworks for wedding or Birthdays etc, it would be a pleasure to have you on board my team if you want to join in.
Lets get in contact so we talk more.

[brocade]

Mr Johnson ive just sent you a U2U with my details you can send me a private email to confirm logistical details

[robert johnson]

In return I have just u2u 'd yourself .
will contact you later on.

[robert johnson]

Made a new spindle today which is 3mm longer in length than before and kept the same nozzle of 13 mm and it worked perfectly. I was able to carry 230 gms of payload to a height of 350 feet[ measured using a measured amount of kevlar thread] so allowing for an increase in drag with the thread attached it should easily reach 400 feet in height next time. I do not think the motor can produce any more thrust with out reducing the reliability which so far is now 100%. Also these motors are very loud when they launch which sounds fantastic.

[Pyromaster2003]

did you use black powder?

[robert johnson]

yes I do, but their again unless you use composite materials then basically they are all a form of black powder. Its just a matter of having the correct tools for the rocket [quality and size] and a particular type of powder.
These rockets work incredabily well but their success did not come overnight.along with every thing else I do it has taken a long long time to perfect and make them safely and reliabily.
I have found that my best fuel is very carefully refined with special attention to the types of charcoal that are used.

[robert johnson]

How are your Lampblack stars drying out, must be nearly ready to use!


Managed to get the lampblack off your hands yet? or every thing else it came in to contact with.

Do you use a dryer for your comps and stars? It makes life much easier I can hold 10 large trays in my drier which is fantastic in winter and it only costs about 5p an hour to run with an average temperature inside depending on the internal humidity of 30 degrees. It also means none of the mixes are any where near my house.

Cheers dears

Rob