My triple r-candy rockets project to lift a 8" shell

[MinamotoKobayashi]

Hello forum.

Unluckly my new 300mm aluminum rocket failed to bring up a massive 4KG+ of firework:

https://youtu.be/H_hN2Dzcdf8

Luckly the hard impact of the firework against the field has detached the massive 8" shell just before its ignition.

 

Here is my new monster, a granulated r-candy powered rocket pressed at 6700 PSI, with a hole diameter of 12mm, a back recess of 20mm and an effective

hole depth of 310mm.

The delay part is 40mm and the unused part on the top is 30mm. 400mm total lenght, 1.5mm wall thickness aluminum case rocket:

 

The recess and the pseudo-nozzle:

 

The unused part:

 

To determine the real altitude reached by the rocket I attached on the top a small light 2" shell filled with only KP with 2% titanium sponge 1000:

 

The finished rocket with 2x1250mm sticks and fuse:

 

The perfect launch:

https://youtu.be/YVMTrrUL8Pw

 

At the moment of the launch the environment temperature was 0°C: at that temperature the speed of sound

is 331 meters/second.

The delay elapsed from the aperture to the perceived BANG was more than two seconds,

so the rocket has reached, more or less, an average altitude of 700 meters, that is very very good:

a lot of juicy thrust for my heavy shells!

But my goal is to attach, on the left and on the right of the main rocket, other two 255mm cardboard

tubes as additional thrust:

 

I have well tested this granulated r-candy powered rockets for my 5" shells and they works great and without CATOs.

Three fast fuses will be used inside the drilled holes and joined to one unique slow fuse to have simultaneous ignition.

If the total thrust will be too much and the altitude reached will be exaggerated, I will proceed to eliminate one of the two additional rockets:

it is better to start with high altitudes rather than with too low ones.

Of course to counterbalance the whole weight (about 5KGs), I will use 4x1250mm sticks, that allow me to obtain a center of gravity just where

the sticks are glued.

This solution is surely not environment-friendly due to the presence of the aluminum tube, but I always found all the falling parts

in the middle of the field the day after, so both aluminum tubes and sticks can be re-used, doing a favor both to nature and the wallet

Stay tuned ...

Edited January 26, 2019 by MinamotoKobayashi

[MinamotoKobayashi]

Well, here is my first prototype of triple-vector granulated r-candy rocket to lift 8" shells:

 

 

 

 

 

 

The shell is empty, but soon will be created an awesome big Kamuro. I have found airfloat coconut charcoal that it is perfect for this kind of effect.

 

I have created two holes into the delay because I suffered some failure with superfast visco fuses (failed shell ignition due to interrupted fuses), and since it is

not a great show to see a 5 KG fireworks fall to the land completely intact, I prefer to put two fuses instead one.

 

The delay thickness is 4 cm, but since it is too much, I created 10mm deep holes, so the fuses will be ignited some seconds before the end of the delay.

It is a good idea to make enough delay thickness due to the high internal rocket pressure, especially the long one, that is pushed to the limit.

A too thin delay is risky because the pressure can blow up it.

 

All the tubes are made in aluminum, ID 27mm, OD 30mm. I changed my original project built with two side cardboard tubes.

The central rocket is 350mm lenght, the other two are 300mm lenght.

The hole diameters are 12mm.

The central rocket has a hole lenght of 310mm, the other two rockets a lenght of 240mm.

The granulated mix (KNO3, Sucrose, RIO, Titanium) was pressed at about 7000 PSI.

 

I used 4x1250mm Samba long sticks to have a decent counterbalancing.

 

The tubes and the sticks will be rescued the day after, to protect the environment and to save some moneys for the next launch LOL.

 

I will post more photos when the rocket will be finished, and if the launch will be successful, the video

Edited February 7, 2019 by MinamotoKobayashi

[pyrokid]

Absolute madman! Now start making color tipped crossettes!

[rogeryermaw]

good lord!! looking forward to this!

[stix]

Indeed!!

[MinamotoKobayashi]

Well, finally the rocket is ready!

 

First layer of Kamuro stars. They were made with a mix of two kinds of charcoals: a coconut airfloat charcoal for initial slow burning

and 20 mesh raw lumpwood charcoal for a long-lasting effect falling sparks:

 

Second layer of Kamuro stars:

 

(Experimental) To be sure that the outer layer will be ignited correctly I filled all the interspaces with granulated fast BP.

They added about 400 grams to the total shell weight.

Then I placed the classical tissue paper bag full of coated rice hulls for the breaking charge.

The smaller 6" shell is another experiment of mine: my first double-petaled shell. It will be launched soon:

 

The finished pasted 8" shell:

 

Double fast fuse inserted into two different holes drilled directly in the pressed mix to be sure to have the shell ignition.

Some cotton balls will help to keep everything in place:

 

A close shot of the custom handmade shell adapters. Three kinds of glue was used: Titebond, Kostrufiss and thermal glue:

 

The three fast fuses joined to an unique fast fuse joined to a slow fuse.

To be sure to have a solid path I cut vertically every fuse for some millimeters and then inserted one inside the other:

 

And finally the monster, a 1900mm rocket with a massive weight near 5 KG:

 

Sincerely, I do not have a place where try to launch this beast.

I'm not sure if it will works correctly, there are too many variables in this project, so I want to be safe, and

try it far away from humans, animals, buildings and trees.

Of course I will post the full launch video when I found the right place.. stay tuned.

Edited March 2, 2019 by MinamotoKobayashi

[dagabu]

I can't wait to see that video! Great job, fantastic build quality! Wow!

[MinamotoKobayashi]

Well, finallly I found a good place to launch this beast and was a big success !!!

Not really a beautiful simmetric aperture but surely a perfect vertical launch.

The three rockets were perfectly syncronized and well conterbalanced, and they lift a massive 8" shell like a plume!

 

https://www.youtube.com/watch?v=9lIPFA4WS_w

Edited April 4, 2019 by MinamotoKobayashi

[Aspirina]

Man... thats is insane, what a perfect work!

My entire respect from Spain

[stix]

Fantastic!!!!!

 

How did you ensure that ALL 3 motors ignited at the same time?

[MinamotoKobayashi]

I used three pieces of superfast Visco fuses (1 meter/second) joined to one piece of the same fuse joined to a normal slow green fuse.

The ending part of every fuse was cutted longitudinally to expose the internal parts, so I was able to insert the fuses one inside the other.

Finally some turns of paper tape assured that every part rests in place.

The superfast Visco fuse is the ideal fuse to ignite quickly the walls of the core burner rockets, instead to ignite first the core and then

the rest of the propellant as usually happen.

In that way the rockets starts quickly and at the same time ...

Edited April 7, 2019 by MinamotoKobayashi

[Aspirina]

Did you re-use the aluminium casing?

 

 

I always found all the falling parts

in the middle of the field the day after, so both aluminum tubes and sticks can be re-used, doing a favor both to nature and the wallet

Stay tuned ...

okey, nice, how many times can you re-use this tubes?

Edited April 9, 2019 by Aspirina

[stix]

 

I used three pieces of superfast Visco fuses (1 meter/second) joined to one piece of the same fuse joined to a normal slow green fuse.

The ending part of every fuse was cutted longitudinally to expose the internal parts, so I was able to insert the fuses one inside the other.

Finally some turns of paper tape assured that every part rests in place.

The superfast Visco fuse is the ideal fuse to ignite quickly the walls of the core burner rockets, instead to ignite first the core and then

the rest of the propellant as usually happen.

In that way the rockets starts quickly and at the same time ...

 

 

Absolutely sensational!!!

 

To get all three motors to light at the same time is more impressive than the shell itself.

 

Good stuff indeed - thankyou. .

[Zmuro]

I'm just speechless. A lot of things has to go right to ensure that all motors start burning at the same time. Can't wait for your new projects

[PyroTop]

Absolutely incredible job on lifting an 8" shell!

Edited April 17, 2019 by PyroTop