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#1 Vic

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Posted 04 February 2009 - 10:11 PM

Does anybody know the optimum mix for whistle rockets using sodium benzoate? I have tried 64/32/1/3 the 3 being Petroleum Jelly on a 4oz rocket. The tooling came from Richard Wolter using 4” tube it started to come back down but 3” was spot on. If I use mix of 76/23/1/3 would there be improvement in thrust or is the tooling optimised for Salicylate whistle?
thanks Vic

Edited by fflach, 20 February 2009 - 09:53 PM.

Freud. Artists, in this view, are people who may avoid neurosis and perversion by sublimating their impulses in their work.

#2 dr thrust

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Posted 04 February 2009 - 10:39 PM

i find 64/32/1/3 just fine for potassium benzo whistle, chances are its your fuel, its very hygroscopic and takes a lot of drying out, copperman stocks pot benzo at a good price

#3 dr thrust

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Posted 04 February 2009 - 10:55 PM

what height is the spindle on the tooling?, and how much did you press above the spindle on the 4"tube?, its just that there's little thrust after the spindle on whistle motors, and they will come back to earth whistling :) if you use to much whistle above the spindle

#4 Vic

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Posted 04 February 2009 - 11:25 PM

Thank you for the suggestion with regards to the hydroscopy of the fuel Chris. I do not think this is the issue as I was very careful to make sure that it was dry, however I will look into it.

The spindle has a height of 1 1/8" with about 2" more fuel after that when I use a 4" tube.

If I changed the catalyst to Copper Oxychloride [not that I have any] would there be any improvement?

Thanks again.

Best regards,
Vic.

Edited by fflach, 11 February 2009 - 09:10 PM.

Freud. Artists, in this view, are people who may avoid neurosis and perversion by sublimating their impulses in their work.

#5 Mumbles

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Posted 05 February 2009 - 04:37 AM

Yes, increasing the Perchlorate, and decreasing the benzoate will increase the power. At least try 70-30. I've seen similar salicyliate mixes to the one you're using mentioned, and they are noted as being far less powerful. I've worked with Wolter's tooling on multiple occasions, and have never had problems. Steve LaDuke, who is what I consider to be the foremost authority on pyro rockets recommends 76-23-1-2 as the hottest mix available. I included the relavent information below.

Copper Oxychloride will indeed increase output. Going back to steve, he said he was having cato problems when using it though.

I would also check the dryness, as already mentioned. Just because it seems dry, doesn't mean that it is. If nothing else works, try cooking it in an oven at about 150C for a few hours, and retry.


From Steve LaDuke:

DWC:
The way I see it, making whistle from the fastest to the slowest, the 76-23-1-2 is the fastest and the 64-32-1-5 is the slowest in any of the fuels used, ben., saly, or potassium ben. And by varing the amount of vasoline in each batch will also slow it down when added.
Here's a good test to see which is more potent: make up a batch of 64-32-1-5 using benzoate and salycilate. Press up a rocket with each fuel and fire side by side. You decide which one flys better.
Now, change the catalist from iron oxide to copperoxichloride and you have a whole new ballgame again. There are a few thousand variables in making up whistle mix. When you find ont that works for your purpose, stick to it. I've probably only used around 35 of those variables and make pretty good rockets that satisfy my needs.
Then change the type of perc you are using. Here we go again. Another few hundred varialbes. This is real science. The art is putting it all together and making it work.
SLD

Edited by Mumbles, 05 February 2009 - 04:45 AM.


#6 dr thrust

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Posted 05 February 2009 - 06:53 PM

agreed, theres a million variables, something i found with my nozzle-less bp motors as well, even the loading pressure on your press can effect the burn rate, i made two identical whistle rockets with the second pressed harder than the first and it hardly got off the ground.
strange thing to, i found the 64/32/1/3 faster than the 76/23/1/2 !???, but that may of been down to, two much Vaseline 1g makes a big difference as well as the amount of solvent used, to wet a mix and the solvent can get locked up in the comp even after a couple of weeks my rockets were chuffing, so now ive got a 100ml granulated glass measuring cylinder to dial in the exact amount of solvent needed.
i find to get good rockets, consistency in production is needed even down to having a timer on my ball mill to mill the individual chems the same every time, I'm just trying to cut down on the variables
also manganese dioxide is a good catalyst, cheap and plentiful from pottery suppliers heres a link to whistle testing press here!
playing around with tooling makes a big difference to, im using tri core stepped spindles at the moment, so maybe treat yourself to a small lathe of ebay? ^_^ here's a link to the stepped spindles bottom of the page

Edited by chris m, 05 February 2009 - 07:34 PM.


#7 Potassium chlorate

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Posted 05 February 2009 - 07:51 PM

Shimizu has a recipe with 67% potassium picrate and 33% potassium nitrate.

Another recipe from the good old times is 67% potassium chlorate and 33% gallic acid. :P
"This salt, formerly called hyperoxymuriate of potassa, is
used for sundry preparations, and especially for experimental
fire-works."

Dr. James Cutbush

#8 Vic

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Posted 05 February 2009 - 09:33 PM

Thanks Mumbles for the reply. I will give the 76/23/1/2 a go also will give the sodium benzoate an airing in a low heat oven. Thanks for the quote from Steve La Duke he is living legend a great inspiration to myself and I’m sure to many others as well.

One odd thing was an occasional spark trailing back about 5’ or so, is this normal? From what I know whistle rockets are clean burning with regards to sparks.

Thanks again to everyone for all the input.

Best regards,
Vic.
Freud. Artists, in this view, are people who may avoid neurosis and perversion by sublimating their impulses in their work.

#9 Vic

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Posted 08 February 2009 - 12:55 AM

Well I tried 76/23/1/3 and the outcome was some increase in power but not much and no whistle just a short sound at the end of the burn (this was only on the longer motor of the two I tested ) I don’t think the sodium benzoate is air milled there were white flakes which didn’t break up in the screening, this may explain poor performance, but why hardly any whistle sound?
Vic
Freud. Artists, in this view, are people who may avoid neurosis and perversion by sublimating their impulses in their work.

#10 ExplosiveCoek

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Posted 08 February 2009 - 10:14 AM

Did you press it hard enough? My nabenzo was airfloat, but still my whistle wouldn't whistle.. I didn't press them hard enough :).

#11 Vic

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Posted 08 February 2009 - 12:03 PM

I used the same pressure on my two ton arbor press for these and my first ones that did whistle.
Vic
Freud. Artists, in this view, are people who may avoid neurosis and perversion by sublimating their impulses in their work.

#12 ExplosiveCoek

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Posted 08 February 2009 - 12:43 PM

Then your nabenzo probably wasn't fine enough, it has to be realy fine powder.

#13 spanner

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Posted 08 February 2009 - 04:53 PM

One odd thing was an occasional spark trailing back about 5’ or so, is this normal? From what I know whistle rockets are clean burning with regards to sparks.

Barring some unknown impurity, this is probably just nozzle erosion or the inside of the case burning and being ejected.

As to the mesh of your fuel, there should be no "grit" felt if a solvent-dampened sample is rubbed between your fingers/thumb. You can check this by putting a small amount in a baggie and kneading it through the plastic.

#14 Vic

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Posted 08 February 2009 - 05:20 PM

Just made second batch of 76/23/1/3. The sodium benzoate was definitely gritty, tried ballmilling and it just clumped up, then the coffee mill and it just stuck to the sides. After considerable amount work managed to get it through 40 mesh screen but still slightly gritty but a whole lot better than the first mix. Will know the outcome tomorrow night
Vic
Freud. Artists, in this view, are people who may avoid neurosis and perversion by sublimating their impulses in their work.

#15 spanner

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Posted 08 February 2009 - 05:35 PM

Good luck w/your new batch- I think it'll be better.

Milling that stuff is the pants (is that how you say it?). Best to get it air milled if possible- I found out the hard way that sometimes a deal, isn't! :(

Only had a pound of it so no big deal, but still.

EDIT- Just occurred to me that you could separate the finest from the rest by screening with a home made screen.

Use an old pair of pantyhose or stockings (women's ;) ) and stretch them over a clothes hangar that has been bent into a circle.

Another way is to cut both ends from a large can and stretch them over one end and secure w/a rubber band. This way, there's only one thickness and will pass the material easier than using the hangar method- it will have 2 thicknesses.

It won't be as easy to screen as Al or KNO3, but you should be able to get some fine from the procedure.

The mesh can be "adjusted" by how tightly you stretch the pantyhose over the wire frame or can end. Tighter = larger mesh.

Edited by spanner, 09 February 2009 - 03:04 PM.





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