New experimental launches.

[MinamotoKobayashi]

Hello forum.

Finally I have found some time to launch my creations.

I have the time to build the items, but I never found the time to launch them .. pretty funny, isn't it?

 

For the first time I used a hot BP rocket propellant instead r-candy granulated mix.

The procedure is the same of my r-candy aluminum rocket tutorial:

 

https://www.amateurpyro.com/forums/topic/13292-making-a-granulated-r-candy-powered-aluminum-rocket-tube-for-6-shells/

 

but I replaced the granulated r-candy mix with hot BP meal plus 4% of phenolic resin.

The meal was slighly wetted with pure ethyl alcohol (98°) to activate the resin and eliminate the unwanted fuel relaxation issue during the packing procedure

(issue accentuated by aluminum tube smooth walls).

The pressure applied was about 8000 PSI.

I drilled the packed hot BP without any kind of issues, in the same way that I drilled the r-candy mix, then I waited that the mix becomed completely dry

inside my dehidratator.

 

Here is the launch:

 

https://www.youtube.com/watch?v=Fn3pPTL4Y_M&feature=em-comments

 

There was some mistakes, but it is pretty normal for the first try:

 

1. The launch was too sloping;

2. The delay was too high, so the rocket start to falling too much before the ignition;

3. The stars core had to be blue, but were a pale washed azure. Besides this, the camera do not caught the real color and show a white appearance.

 

Hovewer, the altitude reached was perfect for a 6" shell.

Next time I will add some titanium (or magnalium) in the delay part to improve the tail.

---

Now it is the time of the second launch.

I improved the procedure for this project:

 

https://www.amateurpyro.com/forums/topic/13373-my-new-1kg-nozzleless-hybrid-propellant-aluminum-tube-rocket/

 

I increased the KP percentage in the mix, so for every 100 parts of hot BP I used 20 parts of KP;

I lowered the phenolic resin percentage from 5% to 4%;

I eliminated the titanium in the mix and added it only in the delay part.

 

The departure of this 1KG rocket was so damn fast that the big heavy stick that I added to the rocket was not enough

to maintain it in the correct trajectory:

 

https://www.youtube.com/watch?v=KZgwUgdKj_Y&feature=youtu.be

 

In the future I will use this rocket to lift heavy shells (correctly balanced of course LOL).

---

And now .. the CATO

Usually I collect all the wasted powders, the ugly malformed stars and the various project mistakes in a container.

Of course I make sure that all the chems are compatible with each other and there is no flash between them!

When I reach the right amount I put the strange mix inside a mortar, I press some paper over it, and I light the mix

with a fuse inserted into a small hole on the bottom of the mortar.

Usually I obtain somewhere between a fountain and a cannon shot .. usually!

This time something very dangerous happened. The pressure inside the 4" mortar was probably too high and the fiberglass mortar exploded!

I never hear a explosion so loud like this! I savor my balls taste!

Luckly my quality mortar was conceived also for this evenience, so no chipping was ejected around: all the dangerous pieces was kept

together with a fluffy skein.

In addition, we were at a safe distance that not to be hitted by the glowing stars.

All in all the show was remarkable, even though I lost one of my mortars

Here is the video:

 

https://www.youtube.com/watch?v=oUyVu5MYfDM&feature=youtu.be

 

All the launches (and CATOEs) was made after a raining day, so all the fields around was very wetted. I always wait for that conditions to

avoid unwanted ignition of grass, brushwood and various reeds ...

Edited March 7, 2020 by MinamotoKobayashi

[SharkWhisperer]

Interesting progression. And your 4" mortar CATO was impressive....yipes!

 

Apart from the tuning-in that you still have to do, what are your general impressions when comparing sugar vs BP for rocket fuel?

 

Always enjoy reading your investigations, and you provide good detail so it's simple to understand your approaches. Fun, fun!!!

[stix]

Great work Minamoto

 

[EDIT] And as Sharky said, great detail and explanations on your methods.

Edited March 7, 2020 by stix

[MinamotoKobayashi]

x Sharkwhisperer:

the "hiss" sound is totally different, and also the tail and the departure.

BP powered motors had smooth sound, progressive thrust increasing and a nice fluffy tail.

Granulated r-candy motors had greater and rough sound, almost instant start and a short rough tail.

If both the powders are well mixed, packed and dried, the thrust seems to be the same.

Of course we are talking about nozzleless motors, that are ideal to lift heavy shell for a short time.

The main two advantages of the BP powered motors are:

 

- They are not hygroscopic as the r-candy motors be, especially when mixed with phenolic resin;

- They do not suffer loss of thrust when the temperature is low.

Edited March 7, 2020 by MinamotoKobayashi

[SharkWhisperer]

x Sharkwhisperer:

the "hiss" sound is totally different, and also the tail and the departure.

BP powered motors had smooth sound, progressive thrust increasing and a nice fluffy tail.

Granulated r-candy motors had greater and rough sound, almost instant start and a short rough tail.

If both the powders are well mixed, packed and dried, the thrust seems to be the same.

Of course we are talking about nozzleless motors, that are ideal to lift heavy shell for a short time.

The main two advantages of the BP powered motors are:

 

- They are not hygroscopic as the r-candy motors be, especially when mixed with phenolic resin;

- The do not suffer loss of thrust when the temperature is low.

Very interesting. What are the comparative disadvantages of using BP? With your specific processing, is there a large time difference in fuel manufacture and consolidation into the rockets? Any notable cost differences? It's surprising to me that, even with equal total impulse, the thrust (as subjectively indicated by motor sound) is nearly maximal very rapidly in a nozzleless sugar rocket and seems to progressively increase in a nozzleless BP rocket--I'd have guessed that without a core, you'd get the more uniform burning throughout, more like a short-cored endburner. Do equal fuel volumes/loads carry the same weight to the same altitude, or you haven't specifically measured vertical maximums yet? I ask many questions because BP rockets are a favorite, and I thought I might test out some sugar rockets, with which I have little experience, just for fun. And you are a pro at sugar rockets!!

 

Anyways, excellent experimenting and reporting.

[MinamotoKobayashi]

Thanks for the kindly words.

For me, the only disvantage of the BP fuel is the charcoal, because it creates a lot of dust and dirties much more. With sugar rockets, I don't need the use of masks

and everything is much more clean. Only a little bit sticky

The time of preparation, granulation and packing is more or less the same. To granulate the r-candy mix I need alcohol that increase a little bit the total cost,

but I do not need charcoal and sulfur, while the classical sugar is cheap. So, more or less, the cost is the same for both the mix.

It seems that the BP powered rocket has lifted the same weight at a greater height.

I think to use the BP powered motors in the winter season, while I will use the r-candy motors in warmer seasons since they work better in a warm environment.

Edited March 7, 2020 by MinamotoKobayashi