19 replies to this topic

[Sparky]

Dear all

I would just like to say that I made my first ever core burner rocket engine this evening and performed a static test and it worked exactly as I imagined it should. Not a clue how much thrust it generated but given the way it tried to bury itself even deeper in the pant pot it was not bad at all. Big woosh, very loud and short until it hit the delay.

I'm using the tooling from oliver brown with 60:30:10 ratios of KNO3, C and S. 7 inch long thick walled tubes.

I have just rammed number 2 and am waiting for darkness for a free flight test :-)

Sorry, had to share as I'm very excited and the family just don;t get it!! !

[Sparky]

OK that was a failure. It started to lift off then blew out the top. Clearly I had not rammed enough BP beyond the top of the spindle and core or possibly not rammed it well enough.

I'll try again tomorrow!

[Vic]

1lb core burners are very good work horse for lifting a multitude of effects.

I know how you are feeling right now

Did you use a top plug?

Edited by Vic, 28 March 2012 - 08:59 PM.

[Mortartube]

It took me years to get rockets flying. No pre-made tools when I experimented. And the feeling when the first one flew (my KNO3 was too coarse was the main problem in the early days), it was just elation, and like you. I just had to tell somone. Rockets are still my favourites to make even after many years. Get the motors producing a reasonable thrust before adding headings. Good luck and welcome to the great world of rockets.

[Sparky]

Thanks guys!

The top plug was almost certainly the issue as I plugged the first one but not the second. I thought it might be possible for the delay section to be strong enough to contain the pressure...clearly not.

Just out of interest...do you usually just make a small hole in this to ignite the header when I get to the point of making them?

[Creepin_pyro]

Just out of interest...do you usually just make a small hole in this to ignite the header when I get to the point of making them?

Yes, and you want it close to the side of the tube. The flame front propagating through the fuel grain will reach this point last, so all of the grain will be consumed when the header is ignited.

[starseeker]

It certainly is a good feeling,i tested a couple of 1lbs in the week,one with timed reports and one with a experimental brocade,which i will post up in case anybody is interested as i was really pleased with it.

If you aim for a 4 to 5mm passfire hole that should do the trick.

Good luck with the test,

[Sparky]

Just rammed 2 more so will be testing again at nightfall

[Sparky]

Wow that was even more impressive than I thought it would be!!

Extremely fast launch, dead straight and vertical flight too.

What sort of size header can these reliably lift?

[starseeker]

Wow that was even more impressive than I thought it would be!!

Extremely fast launch, dead straight and vertical flight too.

What sort of size header can these reliably lift?

200g plus headers no problem,start off smaller and build your way up,

[Sparky]

Sounds great! I'll start very simply I think. I'll just be happy getting some stars up there and lit

[www.oliverbrown.co.uk]

Sounds like you are getting on OK with my tooling, now you have the top plug sorted... Rockets are very addictive, my 3 year old nearly wets herself with excitement each time we let a decent rocket go!
I'd recommend tigertail stars to get you going because they are so easy to make and easy to light, pop them in a paper hemi with a bit of rice crispy burst and you are in business!!
If you get a chance, get a video or some pictures as I'm going to add a gallery to the website soon.

[Sparky]

Yes, works lovely and well worth the investment!

Here's a vid of a motor test. I'd been keen on feedback about how effective it looked.

My girlfriend didn't quite manage to follow it all the way up but you can see a very strong launch. The only thing I might try is a little more delay as it burnt out very quickly compared to a previous test.

I've actually got some hand cut willow stars ready to go so I think it will be the next test :-)

[www.oliverbrown.co.uk]

That looked a stunning launch, very well done Sir.
To extend the flight time make sure you have consolidated the fuel as best as possible and make sure your top plug is right at the top of the tube and your nozzle plug is kept trim, I use 6g of clay.
This is a vid I made a whille ago, same tooling, same comp with a 3" hemi with tigertails, short delay after rocket had finished but still looks fine! ROCKET

[Sparky]

I'll make sure I ram it completely full and I was probably over cautious with the nozzle.

I see you used titanium in yours but I'm slightly nervous about adding metals to the comp as I'm ramming. What do people do about adding effects to the trail but safely? I was going to add some courser charcoal etc or ferro-titanium if its safer to ram than sponge titanium.

p.s. Love the gf (I presume) screaming at the woosh ;-)