21 replies to this topic

[robbstech]

Hi all,
I thought I would share this with you and hope to get some feedback...

I have been making rockets for a few days now and I finally got a few to work today.

Im kind of going about this in a crude way... I got an old drumstick and cut the end off to use as a rammer. For the casing I use 2x 5cm strips of plain A4 paper wrapped round the drimstick and then 2 layers of gummed paper tape wound in opposite spirals.
I then use ground down kitty litter to make the nossle and end plug. this is how I make the rockets.

1) I wind 2 layers of 5cm wide A4 paper round the drumstick and tape it in place.

2) I wind 2 layers of 18mm gummed paper tape round in opposite spirals.

3) I then pour in kitty litter to make a plug about 12mm thick and ram it very hard nd tight.

4) I pour in the meal powder, a little bit at a time and ram it until I have a propellant grain about 3cm long.

5) I then pour in more kitty litter to make the end cap.

6) I then drill a 3mm hold in the nozzel and i continue drilling until I have drilled 1cm into the black powder

7) I then insert the fuse and tape in place

8) I then atatch to a stick (I have been using thin garden canes for stick and balencing them)

9) Light and enjoy


The problem is they are only going about 40 feet high and this is quite dissapointing (better than just CATOing or working but not lifting)

I was wondering if anyone could give me some exact details on how they make their rockets.

Please state;

• Inner Diameter, Outer Diameter and all other dimensions
• Propellent and what ratios and techniques they use to make it
• Weight
• Stick length, wieght
• Nozzel appature size
• All other things I might find interesting

Thanks all
Rob

[martyn]

Hi - I'm afraid I don't make rockets as it's (probably) illegal in the UK.

However, I have found this article very interesting and informative in the past, I believe the author is a member on this forum.

Then there is always good old Skylighter, and there are loads more BP rocket making sites.

I'm sure someone who actually makes them will pop up soon and advise you further.

Cheers.

[Karl]

I'll post up specs later but i've had great success with the 'Estes C' formula;

71.79% Kno3
13.45% Sulfur
13.81% Charcoal
0.95% Dextrin

Just bare in mind that this is designed for end burning rockets and when done correctly, burns very, very quickly.

[Yugen-biki]

Hello!

You can take two different approaches from here.
One: Manipulate the fuel.
Two: Manipulate the tool.

Don't do the two at the same time because it will be very difficult to know what when wrong or what had desired effect.

A simple and good rule of thumb for BP rocket fuel is 6:3:1 KNO3:C:S. Mill it very fine (untill a dark shade of gray) or else cracks will form and increase the burning area uncontrolled = CATO. If it does not work increase ammount of C by 0.1-1% teps. Don't let S drop below 9-10%.

Start by increasing the nozzle diameter. 1/3 of the case inner diameter is a good start. The spindle should go allmost all the way through the fuel. Just leave a few mm for delay for a topping shell if wanted.

Oh yes. The kind of tubes you are making (spiral) are not as good as just rolling the paper in a parrallell orientation. Use craft paper with home made glue from flour and water (you will find instructions here on the forum). Don't glue the first inner part, or else it will stick to the drum stick. Use a wooden block to roll the tube on the stick on a hard surface to push out air boubbles. Pull of the stick and let dry for a few days. The thickness of the tube should be 5-10mm, guessing from remembering the drum sticks


Good luck!

Edited by Yugen-biki, 27 September 2010 - 10:39 AM.

[Mortartube]

my end burners are 18mm ID and 85mm long. They have a clay choke about 10mm thick with a 3mm hole. I use straight willow meal that is milled in a rock tumbler for about 5 hours. They work fine and reach about 150 feet.

For core burners I use a case of the same size but with an 8mm choke. The powder is willow meal, NOT milled. But all ingredients are sieved to be as fine as talcum powder. These also reach about 150 feet. The cavity runs for just over three quarters of the length of the propellant.

Edited by Mortartube, 27 September 2010 - 01:26 PM.

[dr thrust]

hello, firstly congrats on getting your rockets off the ground! well done you.
as for stick weight/length, im sure..the stick should be 8x the motor length.

also the finished motor/stick should "balance" on yer finger, just stick out your finger sit the rocket on your finger just behind the motor and if the sticks to heavy it will fall towards the floor.
may i ask the diameter of your drum stick "rocket forming tool" 11mm?
ho secondly, but i guess you already know this, drilling into a live motor isn't the best,so id say tooling needed! here's a nice pic of simple tooling.
lol just thought ask ten pyro's a question on rockets and get ten different answers!

Edited by chris m, 03 October 2010 - 10:41 PM.

[PyroCreationZ]

I personally haven't got any rocket experience yet but I'm ordering tools as we speak lol.
Well, not ordering yet but requesting a quote.

Anyway, I can't help you out with the requested information though I "know" someone on YouTube wich has a lot of experience and information regarding rockets.
If you send him a PM he'll be glad to give you more info:
See allrocketspsl account
Don't get me wrong, I think there are enough people here on the forum who can/will help you but the guy I mentioned sort of specializes in rockets so...

Good luck!

[robbstech]

Hey all,
I had another go at some rockets today and WOW!

All 10 of my rockets flew very high and perfectly straight!

I will get a video of a couple tonight when it is dark and upload to youtube for you all!

My problem is that they all went well other 800 feet, well out of site and this is too high for my payloads to be seen or heard lol

What can I try?

Thanks
Rob

[dr thrust]

well, tell us what you changed to make your rockets fly so high !

[Potassium chlorate]

My rockets fly very high too, most of the time, but not that straight.

[robbstech]

well, tell us what you changed to make your rockets fly so high !

Well lets start with what I never changed!
1) The fuel. I used exactly the same meal powder in 75:15:10 Ratio, even from the same batch.

What I did change.
1) I changed the casing ID to 18mm
2) The casing length os now 8cm
3) The Nozzel appature is now about 4mm
4) The stick is now 6mm wooden down 83cm long

Now can I just say again, they flew straight as an arrow fairly slowly but perfectly straight.

I did get a chance to put a 1 inch payload on and it bursts bang on apogee but it is way to high to see or hear lol

Thanks

[dr thrust]

ahhh, so you made a bigger rocket !, what was the diameter of your original motor?

[robbstech]

ahhh, so you made a bigger rocket !, what was the diameter of your original motor?

11mm

[robbstech]

I launched a couple tonight, one with a 1" payload and one with a 2"payload.

The one inch worked perfectly, right height, burst at apogee.

The 2" went about 60 feet then fipped upside down and hit the ground under power then burst.

I am getting there though

[PyroCreationZ]

Glad to hear you're making much progress already
Show us!