Princeton University attempt at a suborbital space shot?

[blackjack2564]

https://www.wackywillysweb.com/proddetail.php?prod=HP-short19.90mm..

I did not know about firework star presses when I began 5yrs ago down this road. I found "Wacky Willy" pill press, I don't see mine there...10mm version, anymore. [60.00] Shipped in unmarked brown paper...LOL
Star press is more economical & readily available from pyro supply houses.

Use with vise. Dampen with flexible nitro cellulose [used for flexible fuse coating].
I have made a batch with polyester resin, which is what is called for in mil-spec formula here:





Due to such a small amount ...30 grams only needed 2drops of resin with 2-3% curative...I have not been able to duplicate the actual mil-spec version & i'm not about to waste a .lb trying to figure out the scale down.
The pressed nitro ones work perfect if not a tad susceptible to breakage if not handled proper. I can drop on floor they will not break.

I have used acetone also with success, to dampen. Any suggestions, I'm listening.
I was just fortunate enough to get several pounds [before the shipping debacle] of surplus granules to play with. So far [3yrs] they work every time.

Mil-spec file for making pellets:

 

[saadzmirza]

Just wanted to add that unlike some thermite forumlations, and ZPP, BKNO3 is not static sensitive and is relatively benign/safe to handle. Wish it was easier to obtain without an ATF explosive user permit.

 

[FredA]

Thanks Jim - something to experiment with in the "off season."

 

[jsdemar]

I've been making B-KNO3 igniters without a press. I've detailed the formulas and bomb test results for many igniter formulas in an igniter thread here in the research forum. I use viton pellets dissolved in acetone as the binder as an alternative to nitro lacquer.
Thermite is not a good igniter when tested for what an igniter is supposed to do (heat flux and pressurization gas).
The boron must be amorphous micron sized and not crystalline elemental boron.

The other key to reliable ignition, especially upper stages, is to plug the nozzle to hold 200 to 400 psi. I've been working on a cheap reliable method but I need to do some more tests.

 

[OverTheTop]

As for ESD testing these are pretty good. Have a couple sitting around at work.

Tests up to 30kV, various application rates (single - 20Hz), positive and negative, etc.

I have some igniters sitting the HV lab for a few months now, trying to find time to static testing. Not sure if I will try thermite at work .

 

[RGClark]

Am I the only one looking at that rocket and thinking there was nowhere near enough hardware on that pad to get to the Karman line?
I mean the CSXT rocket needed an S to get up to 72miles and these kids were going on about expecting 80miles. When I saw them loading it on stream, I thought that was a sustainer.
I can’t find dimensions or mass numbers for this thing anywhere. Anyone know where to find them?

Here is some info on their rocket:

https://www.rrs.org/2018/03/03/usc-testing-at-the-rrs-mta-traveler-iii/

They also used carbon composite for the casing instead of aluminum. This saves about 1/2 off the dry weight.

Bob Clark

 

[saadzmirza]

Couldn't agree with you more, jsdemar

 

[markkoelsch]

So what is better to use for lighting a sustainer motor from a safety perspective, a BKNO3 pellet or copper thermite?

Not all thermite is equal depending on particle size and ratio.

Electric matches can be set off by static. I think that is worth thinking about. I am not sure how to test this, but if static triggered the ematch that is another issue.

 

[markkoelsch]

Just don't ask where the BKNO3 pellets came from.
You don't want to know.

Actually, I would want to know especially after you post something like this.

 

[watheyak]

Just don't ask where the BKNO3 pellets came from.
You don't want to know.

Actually, I would want to know especially after you post something like this.

They're BKNO3, not BKYES3...

Sorry. I'm usually the only one who thinks I'm funny...

 

[plugger]

Am I the only one looking at that rocket and thinking there was nowhere near enough hardware on that pad to get to the Karman line?

I mean the CSXT rocket needed an S to get up to 72miles and these kids were going on about expecting 80miles. When I saw them loading it on stream, I thought that was a sustainer.

I can’t find dimensions or mass numbers for this thing anywhere. Anyone know where to find them?

Given their Fathom II rocket went to 144k' in 2017 I have more confidence that they could reach the Karman line when compared to other teams. And similar to what Robert said, using a CF motor casing makes for a higher mass fraction and therefore a more efficient vehicle.

Here's the video of their Fathom II launch.



I suspect CSXT was aluminum rich.

 

[plugger]

As per usual CJ, thank you SO much for the information above. Now I need to see if I can get a line on BKNO3 domestically. I doubt I'll try and get a pill press though, we just had a 1/2 ton MDMA bust in the news today down here and I know the cops aren't really keen on people owning pill presses!

Now with the "other end" of the staging equation, if I recall correctly you've mentioned using paraffin/canning wax to seal staging motors. Is there any set technique you use to accomplish this? do you cast the seal inside the nozzle (if that's even the appropriate way to describe it)?

 

[plugger]

Not all thermite is equal depending on particle size and ratio.

Electric matches can be set off by static. I think that is worth thinking about. I am not sure how to test this, but if static triggered the ematch that is another issue.

So are you saying there's a formulation of thermite that is better to use than BKNO3 Mark?

 

[OverTheTop]

I doubt I'll try and get a pill press though, we just had a 1/2 ton MDMA bust in the news today down here and I know the cops aren't really keen on people owning pill presses!

Move to a different suburb or make your own press

 

[plugger]

Move to a different suburb or make your own press

Heh. Funnily enough it's "your people" (aka Victorians) that I always think of when pill presses come up. I can't think of a pill press without Carl Williams coming to mind.

 

[jsdemar]

You don't need a press.

 

[plugger]

You don't need a press.

Thanks John. Do you have any recommendations for processing BKNO3 into a usable form factor that doesn't require a pill press?

 

[jsdemar]

Thanks John. Do you have any recommendations for processing BKNO3 into a usable form factor that doesn't require a pill press?

In this thread:

Princeton University attempt at a suborbital space shot? #304

 

[plugger]

https://www.wackywillysweb.com/proddetail.php?prod=HP-short19.90mm..

Just clicked through on that link... I was not expecting a keif hash press!

 

[markkoelsch]

So are you saying there's a formulation of thermite that is better to use than BKNO3 Mark?

No, I am not. Thermite can certainly be touchy stuff, but has been proven to work in certain circumstances. What I am getting at is that there are variations on thermite- different components in both composition and particle size. Some variants might be more static sensitive than others.

As alluded to previously, there have been experienced people in the hobby- people who have used plenty of thermite- who have been bitten by it. It is not something to ever be taken lightly. I have never used it- thought very seriously about it though. I decided after people getting bit by it that I was not really interested in it- I really am not interested in skin grafts and such.

 

[grouch]

CJ's pills have the little smiley faces pressed into them for extra luck.

 

[FredA]

I was going to order a press....was torn between the smiley or the skull....
Now, do I stick with "convention" and us a smiley or go rogue with the skull????

 

[pendrin2020]

I like the smiley for the irony, but I like the skull cuz skulls are cool.

decisions.

 

[jsdemar]

Back when I used a press, I got one of the arbor presses from Harbor Freight. I made a form and pin to fit the press.

Much easier and safer to use Viton as a binder for B-KNO3 without a press. As with thermite, the powdered ingredients are static and friction sensitive until wetted out. And the particle size and form of boron makes a huge difference.

 

[Nytrunner]

Um, if motor formulation and such are restricted to the research forum, wouldn't pellet compositions be similar?

 

[plugger]

Um, if motor formulation and such are restricted to the research forum, wouldn't pellet compositions be similar?

Are pellets motors? I don't think so. To quote Bob Krech.

Discussions of Amateur Rocket Motors belong in the Research Forum
The details of how to make your own motors shall not be posted in this public propulsion forum, and will be moved to the private research forum.

To gain access to the private research forum, go here. https://www.rocketryforum.com/showthread.php?17943-Research-Forum-Access

Bob Krech, Research Forum Administrator

Given it's possible (and arguably advantageous) to stage with commercial motors I think it wise to have this information more easily accessible than research motor formulations, especially given the pitfalls of thermite and the dangers associated with its use.

 

[plugger]

A hard choice for Steve and the Tripoli BoD but I believe it's the right one...

 

[RGClark]

Thanks for that. My opinion is that university teams should always have a professional mentor on site during launch preparations for any high power flight.

Bob Clark

 

[FredA]

professional mentor

What is that????

 

[markkoelsch]

What is that????

Great question. The vast majority of us are just hobbyists- not professionals. So, who is to mentor the teams if not “us”?