35 replies to this topic

[a_bab]

I know nozzle less cato because the pressure must be big since they are as fast as a cored nozzle.

Should I bite the bullet and order the 1" tubes? I need rockets for the NYE !!!!! Will they work for a nozzle less BP?

I have:
-hydraulic press with gauge
-sleeves etc

I can make any tooling with my lathe.

[Mumbles]

I'm not sure what happened to cplmac exactly. I haven't heard from him for about a year. Summer is generally a busy time for him with work I would imagine though.

It wasn't until I was reading about Dagabu's work with nozzleless BP rockets that I realized how cplmac got away with using the tubes that he does. The more I read about them, it seems the highest pressure in whistle rockets is developed during the pressing.

[knackers]

On the other hand I don't think they'd work for whistle.

I used spiral wound tubes to make these whistles, they were 1" ID x 4" long with a 3mm wall thickness
spiral wound whistles

[a_bab]

knackers, please give me the specs for the spiral wound tubes (paper: virgin kraft or recicled? Gaps beween the spirals?). A pic would help alot. Also, I'd like to know the pressing pressure you used for these spiral wound whistles and the sleves (PVC?). Was the spindle similar to the one in your avatar?

Were the paper tubes made of some stronger paper? Does it make sense to order more then 5mm wall thickness? 3 mm sounds like really thin for 1", but you proved I'm wrong.

I know, lots of questions...

Edited by a_bab, 31 October 2010 - 10:15 AM.

[knackers]

a_bab, Yes the tooling is my avatar, I'm sorry but i don't know if the tubes are virgin or recycled, i got them from here bits and pieces (although he is still in the process of builing his site back up due to a hacker in his old site). The spiral joint is 1mm wide with the paper laying 1 full turn. I don't have a gauge on my press but its a 4 ton press and i press it to the point where its probably on the verge of splitting ( i don't use a sleave ) i just cosollidate it untill its very firm,( by the feel of my press i would hazard a guess at about the 1 ton mark, afaik the tubes are not made any stronger ( they look like all of my other tubes) but you could always wrapp a few turns around them to make them stronger.
If i could get 5mm+ walled tubes and at a decent price i would but, these are what is available to me and at a reasonable price
4'' long
1'' ID
3mm wall


i hope this has helped you some what even a little bit

Edited by knackers, 31 October 2010 - 11:54 AM.

[a_bab]

Oh, thank you so much knackers.

I'll try to put here some thoughts I have.

People like cplmac with their high performance rockets go for very strong NEPT tubes, which are supposedly the best. Even with these tubes they can have issues, as they use lots of pressing force. Not a good sleve=split in the wall. They press these nozzle-less very hard, with long cores, but these rockets will do tricks such as a 1" rocket would lift 1-2 kg to 500 meters or more with no effort.

On the other hand you just proved that is perfectly possible to fly a whistle with the "crappiest" tube around (spiral, thin walls, gap between the spirals, AND recycled paper). Moreover, the fact that you pressed with no sleves makes for more wonder from me.

Anyway, you've been VERY helpfull. I really appreciate this.

There are just few more things I need to clear up:

1.A spindle drawing (or dimensions)
2.Did you try to attach a payload to these 1" rockets? What would be the maximum lift power?
3.How much fuel? How many increments?

Thank you knackers in advance.

[Dagabu]

Oh, thank you so much knackers.

I'll try to put here some thoughts I have.

People like cplmac with their high performance rockets go for very strong NEPT tubes, which are supposedly the best. Even with these tubes they can have issues, as they use lots of pressing force. Not a good sleve=split in the wall. They press these nozzle-less very hard, with long cores, but these rockets will do tricks such as a 1" rocket would lift 1-2 kg to 500 meters or more with no effort.

On the other hand you just proved that is perfectly possible to fly a whistle with the "crappiest" tube around (spiral, thin walls, gap between the spirals, AND recycled paper). Moreover, the fact that you pressed with no sleves makes for more wonder from me.

Anyway, you've been VERY helpfull. I really appreciate this.

There are just few more things I need to clear up:

1.A spindle drawing (or dimensions)
2.Did you try to attach a payload to these 1" rockets? What would be the maximum lift power?
3.How much fuel? How many increments?

Thank you knackers in advance.

a_bab,

A rocket motor can be made from ANY tube. The question is, how long can the rocket be and will it have to be nozzleless?

I made 50-3# BP rockets for a friend for his sons graduation this last spring. The rockets were to lift a 3" pall shell to 100' . The feat was accomplished by using 3" of thin wall spiral tube, using a 1/2" nozzle, 70:15:10 BP with another 5% coarse charcoal for a standing tail. If I use even 1/4" more tube, they CATO every time.

I use the NEPT tubes that a buddy of mine carries over at Hobby Horse in Wisconsin, USA. They are the very best tubes made, period.

Here are two 3# rockets that I made two weeks ago using spiral wound tubes (recycled), fuse powder pressed to 9000 LPI with no nozzle. They have tiny shell attached and could not be seen from the ground as they went up through the clouds.

BTW- I attach all of my headings with hot glue and use fast paper fuse to pass fire to the header. I also do not use bulkheads on my rockets, the delay acts as the bulkhead and it saves weight. I will post some specs later of the tooling I use.

Dave

[Potassium chlorate]

I thought this pyro lark was a bit of a hobby thing. Why is everybody talking about buying tubes, whats wrong with making them. Paper, thats all they are, paper. I bet 60% of the people on this forum throw enough paper and card in their recycler every week to make enough tubes to last a year. I use cereal boxes, newspaper, old catalogues and even the wrapper around my fish and chips on a friday night. With a bit of good quality wood glue (not just pva ) you can get some strong tubes with a bit of practice. All my rocket motors are made this way and on inspection afterwards, I could actualy use them again.

I use toilet paper rolls for my Bengals. Otherwise I buy all the paper stuff. Laziness, I guess. Though I re-use icecream boxes of plastic etc to keep my chemicals and compositions in.

It would be incredibly cool to make as much as possible from scratch, but like someone mentioned in another thread, it would take an eternity and making potassium nitrate from scratch wouldn't be worth it even economically.

[phildunford]

I've used 'found' spiral wound tubes for 3/4 inch fountains no problem. They were thick ones though that had walls of at least 1/4"...

Many old production fireworks used spiral wound tubes - eg 'traffic lights' - see article in last Spark.

[dr thrust]

my thoughts on the matter, buy the tubes, then buy lots of rockets from a store , use them on nye, and spend a year or so testing motors (yes it takes that long, theres so many variables) by the way ive used 3lb tubes but i find them a bit over the top, 3/4" 1lb rockets are more user friendly, i have a picture here of a 10" long motor, and what goes up most come down, think about it!

Edited by dr thrust, 31 October 2010 - 08:42 PM.

[knackers]

Oh, thank you so much knackers.

I'll try to put here some thoughts I have.

People like cplmac with their high performance rockets go for very strong NEPT tubes, which are supposedly the best. Even with these tubes they can have issues, as they use lots of pressing force. Not a good sleve=split in the wall. They press these nozzle-less very hard, with long cores, but these rockets will do tricks such as a 1" rocket would lift 1-2 kg to 500 meters or more with no effort.

On the other hand you just proved that is perfectly possible to fly a whistle with the "crappiest" tube around (spiral, thin walls, gap between the spirals, AND recycled paper). Moreover, the fact that you pressed with no sleves makes for more wonder from me.

Anyway, you've been VERY helpfull. I really appreciate this.

There are just few more things I need to clear up:

1.A spindle drawing (or dimensions)
2.Did you try to attach a payload to these 1" rockets? What would be the maximum lift power?
3.How much fuel? How many increments?

Thank you knackers in advance.

My pleasure a_bab,
I've read often about NEPT and would love some but expensive to buy due to int' shipping costs. I have made about 15 of these rockets and split the tube once and have had zero cato's, i do have an identical spindle except the taper is about 1--2 degrees off parrallel ( just enough to release the motor easily ) and it works great too but not quite as much power as the pic below.
My motor specs are :- Total weight of motor ( one i just weighed ) = 94.5g.......70.7g fuel.... card tube = 18.8g... Bulk head = 5g ( 5mm thick )
I press 1x diameter increments ( a full 1.5 t-spoon) until the fuel is about 1/4" from the top then press in bentonite just shy from the top, The delay is 20mm.
I have never attached a payload to these so can't speculate of the lift potential but, they are very powerful.


Those 10" rockets Thrusty, Man they are huge ! They must take ages to press, are they difficult to get off the spindle ? One could use them as a baton to keep law and order
Are they nozzless Bp motors ?

Edit :- not long ago i saw some 1/4" ID plastic insert caps, they looked to be about 2" long and yellow by colour, ( used for report inserts with 1/4" time fuse ) Could somebody please point me in the right direction to get some ? Thanks

Edited by knackers, 01 November 2010 - 04:53 AM.

[a_bab]

Thanks knackers, will come back with the results. I'm planning to lift some 4" shells with these rockets. BTW, are you based in Oz?

[knackers]

No worrys a_bab, I am very interested in your results, , I havn't loaded a payload onto these motors because my mortar launched shells were / are working very good and after rocket testing it was less time consuming to bang a lift cup on the bottom of a shell than a rocket motor, i have launched a few shells on rocket motors but they were big motors ( 150mm long x 38mm ID with a 12mm core, 100mm long ) fueled with Bp and they sent my shells into the stratosphere almost ( you almost needed binoculars to see them ).
Yes i am from oz

[a_bab]

The rockets are the reason I hate to carry my mortars racks around. Imagine 6x4" rack around when I'm supposed to be "discrete" (due to a fireworks ban in my area that recently kicked in).

Rockets on the other hand are "fire and forget" kind of items. Moreover you can actually make the motors as long as you want, for some impressive heights. A short fat motor able to lift a 4" to 100 meters using some 50 grams of fuel is much better than half the amount in lift IMO. Albeit more dangerous (cato=problems, flowerpot=nice mine)

[dr thrust]

that spindle is a specifically designed "pusher" for very powerful whistle and wont work for bp, also a rocket with a header is very different from a rocket with no header because of the initial thrust needed to lift the heavier payload.
a short motor will call for a exotic fuel beyond the capabilities of bp