Nozzle vs Nozzleless

[nater]

I still can't get in to nozzleless BP rockets. I like screening a simple BP fuel, pressing a rocket and watching that slow, loud takeoff. My only nozzleless rockets are whistles.

[dagabu]

I completely understand the fantastic tail and the WHOOSH! sound but I really like to lift shells and having a 100% non-CATO rocket that will lift to the same height day and night is a real relief.

 

If I ever retire, I will work on nozzled motors like TR.

[dangerousamateur]

 

Posted Yesterday, 06:00 PM

Quote

 

I burned two motors yesterday and even with ridiculously hot fuel (one was a hybrid), they burned well with no CATO in cheap pulpy tubes.

 

Did you play some expert tricks with you tubes, like waxing or using of strong supports?

 

Neither one, I used Davids Brass Shim Stock support and dry tubes. I don't overdo the pressure either, about 4000 LPI on riced BP.

 

 

One more question:

will your nozzleless motors made that way, how do you fuse them? Do they survive when you quickfuse or topfuse them?

[nater]

I completely understand the fantastic tail and the WHOOSH! sound but I really like to lift shells and having a 100% non-CATO rocket that will lift to the same height day and night is a real relief.

 

If I ever retire, I will work on nozzled motors like TR.

I understand that too, I have CATOs from time to time. My last one was a 1" whistle with a 4" salute that blew about 5' off the rack and made my ears ring the rest of the night.

 

I certainly have a long ways to go to have the consistency and reliability TR has achieved.

Edited May 20, 2016 by nater

[OldMarine]

I popped my first nozzled rocket the other day. My latest batch of charcoal was apparently hotter. I'm going to start screen mixing pre-milled chems so I can adjust the fuel as I go along. Edited May 20, 2016 by OldMarine

[WonderBoy]

I'm with Nate on this, I would much rather just screen mix my BP rocket comp and not mess around milling it. I worked with mostly 1lb, but I would just ram my 1 and 3lb BP motors, and have never had a cato. My 1lb'ers would lift 4" shells no problem. If I want to lift anything more I switch to whistle, then I can throw that 4" on a 4oz motor

 

 

WB

Edited May 22, 2016 by WonderBoy

[innervision]

I've had a lot of bad luck with nozzled BP rockets CATOing. I only do 4oz and smaller and use a 1/2 ton arbor press.

 

I solved the first of the problems by using stronger hand rolled tubes made with casein glue. Now I have no trouble at all with CATOs with my whistle rockets. They fly great.

 

BP still pop. I decided to experiment with nozzleless, so I pressed a 1/4" bottle rocket with the same tooling that i've been also CATOing nozzled with and it flew fast and straight.

 

With confidence in nozzleless, I pressed up a cored 4oz and BOOM. Blew the tube to smitherines and launched a peice of stick that was motor length while leaving the rest still in the launch tube.

 

I'm thinking that my troubles lie in a proper BP grain. I made another batch of red cedar BP, this time 60:30:10 instead of 75:15:10, and added 3% vaseline in hopes that I will get better compaction. We'll see how that goes. If it pops, I'll shorten my spindle a bit.

[schroedinger]

Innercision like you said it is most likely a grain fault. These small rocets normally can take a lot of power. Either you're not compressing righ (what doubt since your whistle works) or the problem is in the bp.

Most likely the charcoal will be the problem. Do you ball mill your charcoal before mixing it and is it a rather stiff type of charcoal lime willow or springy like paulownia? The later didn't work for me in 2 oz rockets even catoing nozzleless motors, whill the first workd really good as hot 75:15:10.

[ddewees]

DD, two days after that rant, I was admitted to Regions Hospital in St Paul for 6 weeks, almost all of that time I spent in a Coma. I may come back to this thread some day but my ego is substantially smaller now and I think I need to spend some time combing through the rubbish to make a valuable reply. I dont think I can do that today, not yet.

 

The bottom line for me is that I have all but abandoned nozzled rockets, the little bit of extra fuel needed to make a nozzleless rocket motor v.s. the greater likelihood of a CATO for a nozzled rocket motor is just not worth the little extra thrust phase length.

 

I burned two motors yesterday and even with ridiculously hot fuel (one was a hybrid), they burned well with no CATO in cheap pulpy tubes.

 

No worries... and thanks for the reply. Glad you're still at it.

[innervision]

Innercision like you said it is most likely a grain fault. These small rocets normally can take a lot of power. Either you're not compressing righ (what doubt since your whistle works) or the problem is in the bp.

Most likely the charcoal will be the problem. Do you ball mill your charcoal before mixing it and is it a rather stiff type of charcoal lime willow or springy like paulownia? The later didn't work for me in 2 oz rockets even catoing nozzleless motors, whill the first workd really good as hot 75:15:10.

 

I am using red cedar charcoal. It seems fluffier than pine but it's been too long to make a comparison with willow and I have never used paulownia. It is ball milled 4 hours and pretty fast. Each increment has a diffused shine to it under light, so it seems like the grain should be ok.

 

Today I pressed a 4oz cored nozzleless, this time with 60:30:10:3(vaseline) and I also ground off some of my spindle since I'd prefer to have a little more space for delay anyway. No CATO, but it took off very slow and quiet, climbed about 30 feet before beginning its arch and popped its BP/dragon egg header around 10 feet above ground and 40 feet from where it was launched. Also flew two 2oz whistles, one that took its dragon eggs to the clouds, and the other being shorter lugged a small ball shell up to the lower end of where i like them to burst. Guess I'll need to lengthen the spindle slightly if I'll be putting more ball shells on them. It was very top heavy.

 

I suppose for my next BP, i'll use the same slower fuel with new shorter spindle and use a nozzle. If it doesn't please, then i'll go back to the hottest BP and nozzleless and work on my teqhnique for pressing a nicer grain.

 

Is it correct to assume that all else being ideal, that a nozzleless BP rocket should never CATO from a too hot BP? I think I remember reading that piping the fuse to the top of the core can, but I always j hook about a cm deep. For whistles, it was CATO city until I started drilling through the side and sliding the fuse in to lay against the bottom of the grain, away from the core.

[schroedinger]

No, no bp should be able to cato a rocket, due to being to hot.

You should be able to top fuse every nozzleless bp rocket and all classic nozzled bp rockets. J-hooking costs you way to much power.

 

For youf size rocket, the core lenght is very critical. They don't have much lifting force anyway, but shortening the spindle will cost you a significant ammount of that. With a shorter spindle you will need to use a hotter fuel to get some good performance.

[dagabu]

No, no bp should be able to cato a rocket, due to being to hot.

You should be able to top fuse every nozzleless bp rocket and all classic nozzled bp rockets. J-hooking costs you way to much power.

 

For youf size rocket, the core lenght is very critical. They don't have much lifting force anyway, but shortening the spindle will cost you a significant ammount of that. With a shorter spindle you will need to use a hotter fuel to get some good performance.

 

Not in my experience, I have made plenty as have others here and elsewhere that can and do pop nozzleless motors with hot, ball milled BP. Scratch made BP? I'll give that to you.

 

Its all in the impulse, the propagation rate and the pressure/pressure wave for the powder burn and in the increments for pressing along with 'relaxation' of the increments along the "glassy" ends of the increments as pressed.

 

I am not sure what what you mean by they dont have much lifting force? The size of the rocket or the nozzleless design? I am sure that we have put that one to bed with all of the testing on the ACME test rigs etc.

 

@innervision,

 

Are you granulating your BP or pressing the raw powder? I have found some cracking in grains when using straight powder, add some water and ball it up, press it through a screen and let dry. Less dirty, makes stronger grains and seems to be a lot more consistent.

 

Top lighting is great for nozzleless... most of the time. I light my red cedar motors with a J-hook about 1/2" in the grain and top light my hardwood charcoal BP nozzleless motors. The willow I will be using this week will be even MORE likely to pop being top lit. This will be a fun weekend to see what it ends up doing.

Edited May 23, 2016 by dagabu

[schroedinger]

Dag, the power aspect is, in of a normal bp spindle and a shortened spindle. Specially in this small rockets, shortening a spindle for just 1 cm, makes a lot of difference, because it is allready 10% of Spindle lenght.

 

I got a 6 mm bottle rocket set, with two spindles, one spindle 7 times i.d. lenght which is flying perfect and has quite some nice power and a benny whistle spindle 6 times i.d. lenght. If i use the bp spindle with hit bp, no problems lifting a 15g header, but same bp with the whistle spindle and you see the rocket arch after 10 m w/o a header. You can allready hear the power difference at take off.

[dagabu]

Dag, the power aspect is, in of a normal bp spindle and a shortened spindle. Specially in this small rockets, shortening a spindle for just 1 cm, makes a lot of difference, because it is allready 10% of Spindle lenght.

 

I got a 6 mm bottle rocket set, with two spindles, one spindle 7 times i.d. lenght which is flying perfect and has quite some nice power and a benny whistle spindle 6 times i.d. lenght. If i use the bp spindle with hit bp, no problems lifting a 15g header, but same bp with the whistle spindle and you see the rocket arch after 10 m w/o a header. You can allready hear the power difference at take off.

 

With small rockets sets, the rules become a little harder to follow due to a multitude of variables. The OP was using a 12mm rocket as the analog, you have decreased the size by 50% and ANY change will result in HUGE changes.

 

Back to my question: I am not sure what what you mean by they dont have much lifting force? In relation to the size or due to the shortened spindle length?

[schroedinger]

Due to the shortened spindle lenght. (Compared to a normal spindle lenght). In 12 mm i only got a 6 times i.d. spindle lenght. No way to get nice working loads out of it with bp. Max 30 g to 100 feet.

[innervision]

 

@innervision,

 

Are you granulating your BP or pressing the raw powder? I have found some cracking in grains when using straight powder, add some water and ball it up, press it through a screen and let dry. Less dirty, makes stronger grains and seems to be a lot more consistent.

 

 

At first I was using granulated until I realized that the batch had dextrin! Then I moved to powder. On the last test, vaseline in an acetone/nathpha mix was added and granulated. It was a pleasure to work with and still burned fairly fast in a pile for being 60:30:10. Using powder is a messy business that I won't be returning to.

 

As for the spindle, I made my tooling so that the spindle is swappable and is held in place with a set screw. It takes about 5min to make another and a couple more min to polish it up real nice. I find it easiest to roll tubes with paper thats 4.5" wide. That gives me a half an inch leeway with the spiraling to end up with 4" rocket tubes so I already use a shorter spindle than the average person I suppose. I'm not looking for maximum lifting power. I'm more looking for a satisfying liftoff sound. The loud tearing sound the whistles provide as they burn the core is VERY satisfying. I might switch to whistle core and a taily comp for delay instead of CATO BP rockets. The only benefit I see to BP rockets is the safer pressing compared to whistle.

[dagabu]

Due to the shortened spindle lenght. (Compared to a normal spindle lenght). In 12 mm i only got a 6 times i.d. spindle lenght. No way to get nice working loads out of it with bp. Max 30 g to 100 feet.

 

Thank you, I get it now.

[nater]

I might switch to whistle core and a taily comp for delay instead of CATO BP rockets. The only benefit I see to BP rockets is the safer pressing compared to whistle.

While I love the sound and takeoff of a traditional BP rocket with a nozzle, for lifting power and reliability I go with whistle.

 

In my opinion, Dan Thames' Super Whistle Fuel is the ideal fuel for a core burning rocket. If this is the sole comp and delay, you get a chirp at takeoff followed by a nice howl during the delay phase. If you press this comp most of the way up the spindle and switch to a BP based comp for the last hollow rammer for the tail, you get the power of the whistle and the tail of BP. It still chirps a bit at takeoff, but mostly sounds like a hot nozzleless BP rocket.

 

This is the motor I have dialed in the best a day is my goto motor for 3/4" rockets. It lifts great, is more reliable FOR ME than pure Sali whistles and pure BP motors. The Benzoate based comp presses nicely. Commercial charcoal work fine, so no searching for the hottest BP possible.

[dagabu]

I am using Steve's Hybrid, 50/50 with standard BP for nozzleless with fantastic lifts of larger shells but alas, no sparky tail or long whoosh! sound.

 

As long as you all are making and flying rockets, I really dont care how you do it as long as you are doing it!

[schroedinger]

Benny whistle rockets are amazing, but storing them can be a problem, as they can take up humidity. Does someone here have experience with pottasium hydrogen phthalate whistle? (Only read the post of steve f on fireworking.com).

[innervision]

I can't for the life of me find Dan's Super Whistle formula. Is it benz based with some added charcoal? I have no benzoates as I synthesize potassium salicylate fairly cheaply from aspirin. Would adding charcoal and using Cu oxy for the catalyst work ok?

 

 

Benny whistle rockets are amazing, but storing them can be a problem, as they can take up humidity. Does someone here have experience with pottasium hydrogen phthalate whistle? (Only read the post of steve f on fireworking.com).

 

I synthesized some potassium terephthalate with the intention of seeing if there is a sound difference from the usual benz or sali, but I cannot get it to whistle. I was hoping that it would since biphthalates are known to. I'd love to hear any experiences with phthalates of any kind...

 

I also synthed some potassium nicotinate, shooting for a different sound. No luck there either and it also likes to suck the juices out of the air.

[dagabu]

The text below is largely borrowed from a link on Google, all rights attributed to Ned Gorski and will be taken down at the authors request:

"Super-Whistle-Fuel, HP-140-4-C, this whistle-rocket-motor propellant was developed by Dan Thames.

The name "HP-140-4-C" was derived from the type of potassium perchlorate he used, HP-140 (Chinese, "high-purity", 140), at a 76:23:1 ratio with the 23 being sodium-benzoate and the 1 being copper-oxychloride. The copper-oxychloride, used as a catalyst with the sod-benz, instead of red iron oxide or other catalysts, really maximizes the power of sod-benz fuel.

The "4" in the name comes from the added 4% mineral oil, and the "C" denotes the addition of 5% charcoal. Ballmill the pot-perc and copper-oxychloride together, since the KM perc is not extremely fine to begin with.

The SWFuel is very potent stuff, comparable to flash-powder in terms of friction/impact sensitivity, and power, so I'm very careful when working with it."

[innervision]

Thank you. Do you have reason to believe that the mix is more sensitive than typical benz whistle or are your concerns for sensitivity for whistle in general?

[dagabu]

Thank you. Do you have reason to believe that the mix is more sensitive than typical benz whistle or are your concerns for sensitivity for whistle in general?

 

I really have no comments, I'll leave that to others as I have settled on making a hybrid fuel instead and have never made "Super-Whistle-Fuel, HP-140-4-C," myself.

 

The quote above is Ned Gorski's and is attributed to him above as well.

Edited May 25, 2016 by dagabu

[ddewees]

Thank you. Do you have reason to believe that the mix is more sensitive than typical benz whistle or are your concerns for sensitivity for whistle in general?

It's just a disclaimer because it's whistle propellant aka organic flash.

 

It's good for work... not sound.

Edited May 25, 2016 by ddewees