11 replies to this topic

[curious aardvark]

Having chatted to various members about rockets at shugborough it seems that people make the motors by building the rocket and then ramming powder into the engine tube which is a bit hit and miss (or rather a bit, whoossh and BANG or fhupp).
Has anyone tried launching an effects rocket with standard model rocket engines ?
Has anyone actually tried making those bloody expensive rocket engines and if so what are they made of. And why couldn't slightly larger versions be used for display rockets built in a modular fashion ?

Definitely seems to me to be the easiest way to build a rocket.

Or (as usual) am I missing something fairly obvious ?

I'd love to be able to produce consistent rockets. I know the emphasis is on shells, which are fairly easy to lift. But you really can't beat the sound of a rocket going up. Modular motors definitely look the sensible way to go.
discuss :-)

[LadyKate]

Has anyone tried launching an effects rocket with standard model rocket engines ?

There is a book on making this type. See: http://www.fireworks...ateurrocket.htm Although he does cored rockets. The end-burners are a bit more sensitive to make but you can do it with time and patience. Once you get your powder and techniques down, you can repeat it fairly easily. However, since they are more design critical, there isn't a magic formula for making them because of that wonderful variable called BP - you have to dial in your own. The construction is easily done by machines which nets good repeatability - when doing them by hand, the construction takes longer than for normal rockets (in my experience).

I use them occasionally when I need a motor and I didn't plan ahead. I also wait for them to go on sale at our local Wal-Mart and pick up lots when they do. You can make motors that are like them - you just have to be careful and do it right. I find it much easier to overkill the construction (go bigger, use a wider throat, make a core) which lets me make little mistakes that don't matter to the inefficient motor. I can make lots of motors that will lift what I need to where I need it for a fraction of the cost.

http://www.wichitabu...ks/rockets.html

Edited by LadyKate, 15 September 2005 - 02:11 PM.

[curious aardvark]

Looks interesting - what's a CATO ?

[Creepin_pyro]

Looks interesting - what's a CATO ?

Google is your friend

click me!

[adamw]

Or (as usual) am I missing something fairly obvious ?

Well... one of the aspects of being a pyro is to make something! Only use pre-made stuff if (like fuse) it is too fiddly or critical, or if you want to rapidly prototype something (you want to test a rocket header, then it is OK to use a bought motor)

[fishy1]

Looks interesting - what's a CATO ?

catos is not good.

neighbours get upset.....

forum search is good.

[The_Djinn]

Thus far my home pressed rocket motors have all been successful... a little to successful as they keep tending to fly out of sight (straight up before any of you start with the wise cracks ). I have used both a standard BP formula and an alternate KCIO4 mix and both but more so the later are very energetic and dont hesitate getting off the ground.

Cato's are normaly down to cracks in the pressed comp or air bubbles forming pockets.. can even be down to poor casings. A little search around the web will turn up the tooling and there is a rocket motor tool set up for sale on the forum at present wich a search will soon turn up.

Nice thing about rocket motors... dont have to wait for it to be dark to test unless you have a payload you are testing as well.

Mark

[Rip Rap]

I have quite a few years experience building cored BP rocket motors. It took me approx 2 years of rocket building / refining technique, before I was confident in the end result.

The obvious first step is to get one to fly properly. This usually involves many trials & tests. That is why it is essential to keep detailed notes of BP proportions, spindle length / diameter, nozzle diameter, whether pressed or rammed (clean BP & candy mix are the ONLY "safe" fuels to ram!) etc etc. These notes will ensure that you can replicate your success & steer clear of your failures. Avoid attaching any type of burst filled header, until you are confident the rocket will rise the necessary distance for safe viewing.

I generally make rammed 10mm ID rockets. (Although I have now started pressing these 10mm ID ones with an arbor press). The tooling is made from Aluminium mounted on hardwood. This is what I have found works for me -

* 10mm ID case, 100mm length
* Spindle 4mm diam 59mm length
* Fuel is BP + 6% extra charcoal
* Increments are rammed so that after ramming only 10mm (same as ID) has been added to grain length. This means that including the clay exhaust nozzle & clay end plug on top of the fuel, 9 seperate rams of 15 blows are needed.
* Ensure there is twice the ID (20mm) of fuel rammed above the end of the spindle. Finish with a 5mm clay end plug.
* I drill out the clay exhaust nozzle (not the BP core) to 5mm. This just keeps on the side of caution to avoid CATO's.
* Always use finely ground ingredients in your composition (charcoal atleast #60 mesh) to ensure consistent compaction.
* After construction, handle carefully & store in air tight container to avoid causing faults / fractures in the grain.

Some of this info will have been given before. Good luck. I personally love making rockets, they are great fun (as long as they work as predicted).

[Frozentech]

Whoosh indeed ! I had put off making rockets for a while, the actual hold up was lack of decent sticks of all things LOL... didn't feel like cutting my own, for some reason cutting 3/8 and 1/4" sticks from scrap on a table saw makes me more leery than ramming comp. Well, I decided to just buy them, found square 1/4" dowel at the Lowes hardware store for $0.65 US apiece for 36" lengths. I felt dumb for putting off rocket launches. So, instead of making another roman candle today, I made 4 oz. rockets. I used milled BP meal dust with 25% of 36 mesh charcoal to slow that down a bit, and 5 grams of ferro-titanium for some bush in the tail. Good thing I added the coarser charcoal, I think it would have blown apart otherwise, it was that energetic .

Didn't feel like making up a shell effect, since I wasn't sure it would lift, so I just taped a red pumped 3/4" roman candle star to the head of it to show me the burn-through time of the motor. Used a core burning tooling set from Wolter to make the motors.

Worked great ! Here's video of one of them.

4 ounce BP rocket

Pardon my shaky camera work and lack of sound. Using a Fuji digital still camera that saves up to 60 sec of video. I think my next major hobby purchase needs to be a good digital video camera. Any recommendations on a good brand for night pyro movie filming ?

Also, on that note, what is a good ( preferably freeware) program for editing and converting video clips on Windows XP ? I normally use cinelerra in linux, but need to have something for windows as well. Thanks.

Mark

PS - would an experienced rocket builder PM me, I want to ask some questions about 1 LB rockets.

[ProfHawking]

Fraid i havent a clue about the videocamera, its on my xmas list too. but editing:
Dr Divx is a simple & efficient video editor, but its not quite free... COUGH
proper free, & powerful is Virtualdubmod will encode video etc, but its not that simple.
Sony Vegas video is inefficent (i think) and expensive, but very powerful for editing video.

I think my rocket tooling from america arrived today, but nobody was in to sign for it will go to post office tomorrow, hopefully i'll have a decent rocket or two within ~26hrs

[Frozentech]

I think my rocket tooling from america arrived today, but nobody was in to sign for it will go to post office tomorrow, hopefully i'll have a decent rocket or two within ~26hrs

I haven't seen any posts on it, but how do you like your new rocket tooling, and how are the rockets coming ?
I've been ramming rockets left & right, and until tonight, no cato's, but my streak is over

I wanted to get more lifting ability with small rockets, so I decided to try using straight BP that was milled, corned, and sieved meal. Basically 'left over' fines from making 2F equivalent. Anyhow, I was launching an inert 1.75" ball shell as the header, ( weighted to 45 grams ), rather, *trying* to launch, on a 4 ounce rocket... it launched, but I sure don't know where to ! Here is a photo of the only recovered pieces. Made a nice salute though



Tomorrow I'll try again, with 20% and 10% additional 36 mesh charcoal.

[ProfHawking]

ive had great fun with the motors, both sizes work well
Here are just the motors:
http://clintweb.co.u...lfinchmotor.avi
http://clintweb.co.u...rocketmotor.avi

Next steps are to put fancy headers on, but im working on that still. been a bit busy lately, maybe over xmas break i will have some time.