47 replies to this topic

[sizzle]

Thanks for the help everyone, if anyone has any smaller tubes that would be good for rockets, share the wealth

[Pretty green flames]

Hows this for a rocket.

First proper working rocket!
It was charged with a 40gram blank payload to test if it could lift it, and...it did.
I'm happy.
This weekend i'm going to try a 2 inch shell on top of that and we'llsee how that goning to go.

[Frozentech]

Hows this for a rocket.

First proper working rocket!
It was charged with a 40gram blank payload to test if it could lift it, and...it did.
I'm happy.
This weekend i'm going to try a 2 inch shell on top of that and we'llsee how that goning to go.

Classic !

[Pretty green flames]

How's this for a rocket. Made this 1 day before NY but i just got around posting it here.

Enjoy
1/2" rocket with 2" canister payload.

[Frozentech]

I would like to publicly thank Alany and LadyKate for the clues that cured my CATO problems

I was so happy to be consistently shooting successful rockets I went ahead and bought a decent
video camera to record them ( I was going to buy a digital video cam in a couple months but the
pyro pushed me to do it now... I am not a patient man LOL )

Here's my first digital video with sound :

[alany]

Nice rocket!

Don't you just love that delay from the flash to the bag... You really know its got up there when you observe that.

What were the details of that device?

[Frozentech]

Nice rocket!

Don't you just love that delay from the flash to the bag... You really know its got up there when you observe that.

What were the details of that device?

Thanks.

It was a 1/2" ID tube, cut to 6" long, with a straight bentonite rammed nozzle. Propellant was your "RP", with 6% of "Firefly" Al from Skylighter ( CH0155 ) +40-325. I used Wolter's cored tooling. The final increment was roman candle delay with 5% ferro-titanium, topped with 1 gram of 70/30 flash. The flash was capped with tissue paper and hot glue. Stick was 1/4" square, 24 inches long. I quit struggling with ripping my own sticks with a table saw, and just buy 36 inch square dowels at a local hardware store for $0.68 US apiece, I went and bought 20 more sticks today I could probably find them cheaper if I search around, but these will do for now.

I've lifted two 50 gram 2" round shells with these rockets just fine, my delay fuse on one shell was long, and it burst on the way down, but it did reach 200+ feet I estimated.

Next project is to try a 1# rocket with the RP and then a test lift with a 3" dummy shell, after that "the sky's the limit" eh ?

[alany]

I've never made anything larger than a 2 oz (3/8" ID) rocket with RP, I always assumed it would CATO rather violently. I'll have to give that a try. Did you mill and dampen, then granulate the RP? Perhaps yours is a bit cooler than mine?

I haven't used RP for quite a long time actually. I no longer make 9.5 mm x 50 mm motors, I've gone the more traditional route since I got my 2 oz tooling set from Wolter. There is a much larger body of work in the community to draw from on that tooling with BP variants.

I do have a small quantity of RP left from my last batch, but I hadn't planned to make any more after it was gone. I use it now mainly for comparison experiments. BP variants seem easier to tune and are cheaper, but RP does have that "different" tail effect and some unusual properties which give it a certian charm.

Based on some recent burn-rate experiments, RP with good charcoal burns about 7.5 mm/s under my testing conditions. My 6:3:1 "gold standard" rocket propellant which is actually fairly cool for 4 oz motors burns only 4.6 - 5.4 mm/s depending on the charcoal and preparation method.

I know that 7.5 mm/s 6:1:1 BP will cato 1/4" rockets on SBR tooling, which is why I had assumed RP would be too hot for 4 oz motors on standard tooling. I guess I'll have to try it and see.

[Frozentech]

I've never made anything larger than a 2 oz (3/8" ID) rocket with RP, I always assumed it would CATO rather violently. I'll have to give that a try. Did you mill and dampen, then granulate the RP? Perhaps yours is a bit cooler than mine?

I haven't used RP for quite a long time actually. I no longer make 9.5 mm x 50 mm motors, I've gone the more traditional route since I got my 2 oz tooling set from Wolter. There is a much larger body of work in the community to draw from on that tooling with BP variants.

I do have a small quantity of RP left from my last batch, but I hadn't planned to make any more after it was gone. I use it now mainly for comparison experiments. BP variants seem easier to tune and are cheaper, but RP does have that "different" tail effect and some unusual properties which give it a certian charm.

Based on some recent burn-rate experiments, RP with good charcoal burns about 7.5 mm/s under my testing conditions. My 6:3:1 "gold standard" rocket propellant which is actually fairly cool for 4 oz motors burns only 4.6 - 5.4 mm/s depending on the charcoal and preparation method.

I know that 7.5 mm/s 6:1:1 BP will cato 1/4" rockets on SBR tooling, which is why I had assumed RP would be too hot for 4 oz motors on standard tooling. I guess I'll have to try it and see.

Hmmm.... now you've got me wondering ! I thought the performance of the 4 oz rockets with the RP was actually hotter than I expected. I rammed them with RP meal, milled for just 1 hour. I had planned to
moisten and screen the RP comp for the 3/4" rockets though, just too much blowback when ramming the larger tubes. Messy.

what are the testing conditions that you use for your burn rate testing ? I've rigged a stopwatch to trigger externally, and bought some small microswitches to make a Dan Williams style trough tester, I need to go buy a piece of angle iron and get that built soon so I have something more than empirical data on my BP's quality and speed.

I think I will press on (hehe...) with my plan to try a 3/4" rocket with RP, I'll just be aware of the stronger possibility of a CATO of large proportion. I'll post the results.

[alany]

To do my burn-rate tests I charge 1/4" tubes 2" long about 1/2 full. I charge them flat against the desk, so at the powder is flush with the end of the tube. Then I measure the powder train length with a vernier caliper (one that can measure depth and subtract from the tube length).

The tube is then ignited with blackmatch and the burn recorded on video with a digital camera. The audio track gives quite reliable (nearest 10 ms or so) burn times, but a stop watch can be used on the video if the audio is too weak. I use an audio spectrogram program (Baudline) to extract the data, its waterfall view makes it easy to see and measure the time the composition was actually burning.

If you wish to replicate the conditions as exactly as possible, I use Pyrotube 1/4" ID x 2" tubes. I weigh the tube carefully before and after charging so I can get a good approximation of the density I rammed the composition to. This is more useful for repeatability than normalizing the results.

I place the charged tube empty-half up in a testing stand which I made from a 20 mm off-cut of 2 oz (Skylighter) rocket tube hot-melt glued to a plastic jar lid as a stand:

http://www.vk2zay.ne...ment.php?id=685

I should probably start another thread on this actually. Several people on the #pyrotechnics IRC channel (on the chat4all network) have replicated this experiment on their BP meal and we have compared results.

My latest results are here, but I haven't finished the documentation yet:

http://www.vk2zay.ne...vice.php?id=210

I want to compare these against the static test results of the rocket motors using these propellants. I've already observed that RP's thrust output was lower than predicted by its burn-rate alone and need to do more experiments to study this.

[Frozentech]

I've never made anything larger than a 2 oz (3/8" ID) rocket with RP, I always assumed it would CATO rather violently. I'll have to give that a try. Did you mill and dampen, then granulate the RP? Perhaps yours is a bit cooler than mine?

I haven't used RP for quite a long time actually. I no longer make 9.5 mm x 50 mm motors, I've gone the more traditional route since I got my 2 oz tooling set from Wolter. There is a much larger body of work in the community to draw from on that tooling with BP variants.

I do have a small quantity of RP left from my last batch, but I hadn't planned to make any more after it was gone. I use it now mainly for comparison experiments. BP variants seem easier to tune and are cheaper, but RP does have that "different" tail effect and some unusual properties which give it a certian charm.

Based on some recent burn-rate experiments, RP with good charcoal burns about 7.5 mm/s under my testing conditions. My 6:3:1 "gold standard" rocket propellant which is actually fairly cool for 4 oz motors burns only 4.6 - 5.4 mm/s depending on the charcoal and preparation method.

I know that 7.5 mm/s 6:1:1 BP will cato 1/4" rockets on SBR tooling, which is why I had assumed RP would be too hot for 4 oz motors on standard tooling. I guess I'll have to try it and see.

Well... some follow up to the RP in various size rockets question. Although I get great success in 1/2" rockets with your RP formula +5% firefly Al, the 3/4" rocket I test-fired tonight CATO'd about 30 feet up within 1/10th of a second after launch. It was an impressive launch though. No video , I somehow managed to pause the camera after lighting the visco as I was backing off rapidly to safer ground LOL... It was a fine arial salute !

It was a major struggle to get that rocket off the tooling, I ended up having to use two small strap wrenches to twist it off, with a notable *squeaking* as the rocket loosened up off the spindle. Possibly I damaged the core, but to be on the safe side, I made up some "Degn 1lb rocket" comp, and got some dry-lube PTFE spray for the spindle and some graphite powder. I plan to add about 5% to the bentonite for the nozzle and 5% to the fuel comp. Hopefully she'll slide out easy then 3/4" launch #2 tomorrow night.

[Maineiac]

A light wipe of graphite will allow easier removal from the spindle. Wolter tooling? Degn #1? Too much like work. No need to complicate the issue with various charcoal meshes and adding things to the nozzle material. Save your airfloat for other uses. Straight 80 mesh is all you need and the mixed hardwood ala Skylighter or Ace pyro is quite sufficient. The best BP rocket comp I've seen for 1# motors is simply 58/33/9. Dampen with no more than .5% H2O and run through a 20 mesh screen a couple times. Makes for a much cleaner process. These motors lift 350 grams reliably and I've seen them lift more. Using 60% nitrate invites catos. Soundly pressed 8oz motors using 60% have proven to be on the razors edge of cato. Ignition comes with a sharp "pop". And that's before doing typical core mods!
Can I assume that you are pressing these motors rather than ramming them? Pressing sleeve? Good luck with launch #2!

[Frozentech]

A light wipe of graphite will allow easier removal from the spindle. Wolter tooling? Degn #1? Too much like work. No need to complicate the issue with various charcoal meshes and adding things to the nozzle material. Save your airfloat for other uses. Straight 80 mesh is all you need and the mixed hardwood ala Skylighter or Ace pyro is quite sufficient. The best BP rocket comp I've seen for 1# motors is simply 58/33/9. Dampen with no more than .5% H2O and run through a 20 mesh screen a couple times. Makes for a much cleaner process. These motors lift 350 grams reliably and I've seen them lift more. Using 60% nitrate invites catos. Soundly pressed 8oz motors using 60% have proven to be on the razors edge of cato. Ignition comes with a sharp "pop". And that's before doing typical core mods!
Can I assume that you are pressing these motors rather than ramming them? Pressing sleeve? Good luck with launch #2!

Well I launched 1 pounder #2 tonight, it was a success !

It was rammed, on Wolter tooling, using the Degn#1 rocket comp, slightly modified by using half airfloat, milling 1 hour, and adding 1/2 36 mesh charcoal and 5% firefly aluminum. I did add some graphite to both the bentonite clay and the comp before ramming, as well as wiping the spindle down with it. The rocket came off the spindle much easier, but still required the use of a strap wrench to get it loosened.

Here's the video:

[Maineiac]

Well I launched 1 pounder #2 tonight, it was a success !

It was rammed, on Wolter tooling, using the Degn#1 rocket comp, slightly modified by using half airfloat, milling 1 hour, and adding 1/2 36 mesh charcoal and 5% firefly aluminum. I did add some graphite to both the bentonite clay and the comp before ramming, as well as wiping the spindle down with it. The rocket came off the spindle much easier, but still required the use of a strap wrench to get it loosened.

Here's the video:

Looks good! Time to start some inert lift tests I'd say. Get a good baseline from a few motors and then try modifications in process. The biggest gain I've ever found was moving from ramming to pressing with a sleeve and then lengthening the core with a drill (hand spun!) for more initial thrust. The other mod I was taught was to only use quickmatch as fuse. Save the stubs from e-matching displays and you'll have a lifetime supply! Turns ignition into a crisp "pop".
Keep us posted on your progress.

[alany]

Nice.

Did you run blackmatch up the core, or just tie visco into the nosing?