Winokur 39J - Single Shot And 5" Shell Sugar Rocket Powered

[MinamotoKobayashi]

Here is my last experiments with Winokur 39J stars.

 

This is a good single shot 25mm near-rounded star, Monocapa primed.

Added also some grams of Dragon Eggs (the initial crackling sound):

 

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I didn't know that the Winokur 39j had a pleasant crackling sound itself!

 

Here is how I built the mini single-shot mortar.

I saved a used italian "Martarello" tube:

 

Inserting a 10cm long time fuse (the hole present in the tube was perfect for this kind of fuse):

 

10 grams of granulated 2FA fast BP is the right quantity for this kind of device:

 

Putting the powder inside the tube and close it with an handmade perforated cardboard washer:

 

Carefully pressing the washer with a rammer until it reach the powder:

 

This is the (raspberry) Winokur 39J star primed and dried:

 

Adding three grams of Dragon Eggs:

 

Inserting the star, the Dragon Eggs, an another handmade not-perfored cardboard washer:

 

Carefully pressing the cardboard washer until it reach the stars:

 

Gluing a stabilizing cardboard base:

 

 

Now, here is the launch of a ONFA 5" shell with (smaller) Winokur 39J stars and Dragon Eggs, powered by a 250mm granulated sugar rocket:

 

v=Z5OhGzBORWs

 

There was some difference between the stars used in the two videos:

the single shot star was made from a mix milled in a ballmill soaked in bioethanol, dried, granulated thru a 60 mesh sieve

and finally screen-mixed with Aluminum and Magnalium.

I created 10mm cylindrical stars with a star plate and then rolled in my star roller until reached the correct diameter, then primed

with Monocapa and finally dried in a dehidratator (only strong airflow, no heat) for three days.

I used both dextrin and phenolic resin, wetted with a mix of 70% demineralized water and 30% bioethanol.

 

The ONFA shell was made with smaller shells created from 2mm lead shots.

The chems was only screen mixed, no ballmill used.

Same priming procedure as above.

 

It seems that the ballmilled version is much better and elegant, so now I'm building a double petalled 8" shell with smaller Jopete's fucsia

stars plus strobe ad the center and big Winokur 39J stars as external layer. The result should be fantastic .. stay tuned!

Edited July 10, 2020 by MinamotoKobayashi

[SeaMonkey]

Very nice and informative sequence of photographs!

 

Very nice effect in the video too!

[Blackmach]

Good work Minamoto!!

[Bigmark]

Really nice work.

[Dylman]

Minamoto, That was a beautiful rocket with a nice bushy tail streaming from the motor, the shell broke beautifully. I know some would say that the timing was a tad off with the burst of the shell not breaking at the apogee. But I thought it was amazing. Keep up the great work. Thanks for all the photos to document it all. Thanks again, Dyl

[MinamotoKobayashi]

Thanks for the kindly words.

Yes, it is difficult to calculate perfectly the ignition altitude using rockets as lift. Some extra delay or a hole too deep in the delay can vary the altitude a little bit.

Also, sometimes it is enough to add a heavier or longer stick to vary the final performance.

Luckly we are amateurs and not professionists, so we can do all the mistakes we wants without anyone having to scold us

Edited July 11, 2020 by MinamotoKobayashi