Nozzle less rockets

[Pyropow3r]

Long story short here is my goal to make a nozzle less rocket using bp fuel (75/15/10 of course duh!!!! ) to lift 2 inch ball shell salutes using rocket motors of a size of 1inch and up

 

Yes i know its a very large motor for a 2 inch payload but thats the point. That is the effect i want A high altitude salute. lets say around 300 - 400 meters..........

 

Here is what i know to do so far ........

 

Use full strength 75/15/10 bp

 

Add mineral oil to bp

 

correct stabilization

 

DONT make a clay nozzle but DO make a clay bulk head

 

 

what i don't know ......

 

How long would i need to make the core for lets say a 1 inch I.d rocket..... just a rough idea ??????

 

Would wolter pyro 6/3/1 tooling be adequate the core looks like it could be long enough.....6/3/1 with nozzle 75/15/10 without nozzle. I dont know? it looks like it well could do....

 

So somebody HELP ME!

 

Anyone here have experience with nozzle less rockets ????

[Mumbles]

Here is some info for you.

 

http://www.wichitabuggywhip.com/fireworks/rockets/nozzleless.html

[dagabu]

Long story short here is my goal to make a nozzle less rocket using bp fuel (75/15/10 of course duh!!!! ) to lift 2 inch ball shell salutes using rocket motors of a size of 1inch and up

 

Yes i know its a very large motor for a 2 inch payload but thats the point. That is the effect i want A high altitude salute. lets say around 300 - 400 meters..........

 

Here is what i know to do so far ........

 

Use full strength 75/15/10 bp

 

Add mineral oil to bp

 

correct stabilization

 

DONT make a clay nozzle but DO make a clay bulk head

 

 

what i don't know ......

 

How long would i need to make the core for lets say a 1 inch I.d rocket..... just a rough idea ??????

 

Would wolter pyro 6/3/1 tooling be adequate the core looks like it could be long enough.....6/3/1 with nozzle 75/15/10 without nozzle. I dont know? it looks like it well could do....

 

So somebody HELP ME!

 

Anyone here have experience with nozzle less rockets ????

 

A few questions first:

 

1. Why no nozzle?

 

2. Why a 3# motor?

 

3. Why add oil?

 

You can easily reach 900-1200 feet with a nozzled motor but nozzleless motors tend to provide lower thrust, smaller impulse and overall less performance then nozzled motors. Even if you are to use a 3# BP motor in a nozzleless motor, the height would be limited to the thrust curve which in using a standard Wolter 3# BP spindle would put you at 500-600' since it would start to coast at 300-400' and would be turning at apogee.

 

It seems that you are leaving out the most important piece of the motor.

 

IMHO

[Updup]

A few questions first:

 

1. Why no nozzle?

 

2. Why a 3# motor?

 

3. Why add oil?

 

You can easily reach 900-1200 feet with a nozzled motor but nozzleless motors tend to provide lower thrust, smaller impulse and overall less performance then nozzled motors. Even if you are to use a 3# BP motor in a nozzleless motor, the height would be limited to the thrust curve which in using a standard Wolter 3# BP spindle would put you at 500-600' since it would start to coast at 300-400' and would be turning at apogee.

 

It seems that you are leaving out the most important piece of the motor.

 

IMHO

 

I think...

 

The oil allows the BP to pack better in the tube, also it keeps things less messy.

 

And the point of a nozzless motor is to greatly decrease the chance of a CATO.

 

Mabye he thinks 3# is what it would take to lift a 2" salute to the desired hight.

[dagabu]

Gotcha!

 

If you want to make the BP less messy, wet and granulate it. Oil, even 1% will decrease the propagation time of the flame envelope (it wont burn as fast) and you will get a longer burn with a lower impulse. While its true that you will go higher with a bigger rocket, it is a lot like using a sledge hammer to drive 1/2" brads.

 

An 8oz. rocket made using the Universal Tooling and Hybrid fuel will get the heading up to the same height as a 3# BP rocket nozzless but it will use 1/5th the fuel (125g vs. 25). As far as CATOs go, It's best to make a reliable motor first so that CATOs are no longer a worry.

[Updup]

Gotcha!

 

If you want to make the BP less messy, wet and granulate it. Oil, even 1% will decrease the propagation time of the flame envelope (it wont burn as fast) and you will get a longer burn with a lower impulse. While its true that you will go higher with a bigger rocket, it is a lot like using a sledge hammer to drive 1/2" brads.

 

An 8oz. rocket made using the Universal Tooling and Hybrid fuel will get the heading up to the same height as a 3# BP rocket nozzless but it will use 1/5th the fuel (125g vs. 25). As far as CATOs go, It's best to make a reliable motor first so that CATOs are no longer a worry.

 

Interesting, as a lot of people apear to use mineral oil in thier rocket making. And while I agee that nozzless rockets have really bad efficiency, its still cool, that potential power still seems to show, in a diffrent way... That's just from the videos i've seen.

 

Anyway, I'm not supporting one or the other... I don't make rockets.

[dagabu]

"Nozzle less rocket using bp fuel (75/15/10 of course duh!!!! ) to lift 2 inch ball shell salutes using rocket motors of a size of 1inch and up. Yes i know its a very large motor for a 2 inch payload but thats the point. That is the effect i want A high altitude salute. lets say around 300 - 400 meters."

 

900-1200 feet....

[WonderBoy]

There was an interesting discussion about the difference between nozzless and nozzled motors on passfire a little while ago, when I have more time I will wade through it and post some of the info here. From what I remember, one big plus is that without a nozzle, one can fit more fuel in the tube. Also the absense of a nozzle allows the motor to produce more gas and other particulate without blowing the rocket. More gas equals more thrust. Granted I generally use a nozzled design for my BP motors and a only go nozzless for whistle motors. But I do have a little experience with nozzless.

Here's a 3lb nozzless motor using fuel a little more powerful than 75-15-10 (given to me by Dan T.) on Firesmith BP tooling with ~2" whistle as a bulkhead. 3" salute header.

And here is a 2 stage nozzless whistle, I think, 2" motor made by Dan T with six 5" shells on it.

So nozzless can definitely give you power, but using only 75-15-10 BP you may need a fairly long spindle, unless you decide you don't want that salute so high, then you can just make a rainbow rocket like me (sarcasm).

Edited September 27, 2010 by WonderBoy

[Pyropow3r]

You ask why use oil......for the very same reason we use oil/waxes in nozzle mix.

 

Also some of you think nozzle less rockets are weak.....this is however wrong. Here is why.

 

- more fuel

 

- less weight

 

- better thrust curve

 

- less variables e.g nozzle diameter, nozzle erosion etc....

 

All you need to control is the one variable core length.

 

Whistle rockets are high power and they are nozzle less to. The same should apply for bp nozzle less you just need a longer core.

 

I think you guys have seen too many you-tube videos of UN tuned nozzle less rockets.

 

On DJ's nozzle less rocket page he has a 1# or 3/4 I.D nozzle less bp rocket that can lift a 650 gram header 400-500 feet !!!

[dagabu]

You ask why use oil......for the very same reason we use oil/waxes in nozzle mix.

 

Also some of you think nozzle less rockets are weak.....this is however wrong. Here is why.

 

- more fuel

 

- less weight

 

- better thrust curve

 

- less variables e.g nozzle diameter, nozzle erosion etc....

 

All you need to control is the one variable core length.

 

Whistle rockets are high power and they are nozzle less to. The same should apply for bp nozzle less you just need a longer core.

 

I think you guys have seen too many you-tube videos of UN tuned nozzle less rockets.

 

On DJ's nozzle less rocket page he has a 1# or 3/4 I.D nozzle less bp rocket that can lift a 650 gram header 400-500 feet !!!

 

Looks like it turning into an argument here, I am sorry if I am coming off that way but I do want to argue my point, what I am saying is that you cannot make 1200' on a 3# BP nozzleless rocket.

 

I am wondering if you can provide some information on your claims that you have above. In weighing my 9" long 3# nozzled motor vs. my 9" 3# nozzless motor last night, there was 4g difference between the two in total weight. Yes, there is more fuel but as soon as the grain lights, whatever extra fuel was added is exhausted in a microsecond and the *nozzle opens up too much to create enough lift for a 1200' lift.

 

Also, you mention thrust curve, could you please post the two graphs side by side so we all can see what you mean by "better"?

 

Again, I have NOTHING against nozzleless rockets, they are terrific at dumping copious amounts of fuel (and huge tails) in a second but are not able to reach the heights you call for with the slow fuel and lack of thrust that a nozzless rocket provides.

 

Hell, I would LOVE to be proven wrong, lets see a tut on these and some flight video. The weather here is good and I have three 3# motors with 2" cans on them to measure flight end. I will fly them tonight and take video.

 

1. Nozzled 3# fuse powder, 125g fuel grain.

2. Nozzled 3# Hybrid, 125g fuel grain.

3. Nozzleless 3# 75:15:10 (no oil) BP, 150g fuel grain.

[WonderBoy]

Dagabu, what spindle are you using? Also, I assume you are pressing them; may I inquire as to what pressure on the comp?

[dagabu]

Dagabu, what spindle are you using? Also, I assume you are pressing them; may I inquire as to what pressure on the comp?

 

In the three motors I will shoot tonight, I will be using the Universal Tooling for this test but I can do a BP tooling test as well but will need a some time to make the motors.

 

Yes, I am pressing, pounding is, in my opinion, best for spollettes and small rockets but once you use anything but plain BP, you can no longer pound.

 

I put 9000 psi on my comp, 3" piston, 1" ram, 1000 psi on the dial = 9000 psi loading pressure.

 

Sorry, I lost the fuse to the nozzleless on the way out to the range, you will have to deal with just the two for tonight.

 

LINK

Edited September 28, 2010 by dagabu

[dagabu]

Sorry, I lost the fuse to the nozzleless on the way out to the range, you will have to deal with just the two for tonight.

 

LINK

[Pyropow3r]

Looks like it turning into an argument here, I am sorry if I am coming off that way but I do want to argue my point, what I am saying is that you cannot make 1200' on a 3# BP nozzleless rocket.

 

I am wondering if you can provide some information on your claims that you have above. In weighing my 9" long 3# nozzled motor vs. my 9" 3# nozzless motor last night, there was 4g difference between the two in total weight. Yes, there is more fuel but as soon as the grain lights, whatever extra fuel was added is exhausted in a microsecond and the *nozzle opens up too much to create enough lift for a 1200' lift.

 

Also, you mention thrust curve, could you please post the two graphs side by side so we all can see what you mean by "better"?

 

Again, I have NOTHING against nozzleless rockets, they are terrific at dumping copious amounts of fuel (and huge tails) in a second but are not able to reach the heights you call for with the slow fuel and lack of thrust that a nozzless rocket provides.

 

Hell, I would LOVE to be proven wrong, lets see a tut on these and some flight video. The weather here is good and I have three 3# motors with 2" cans on them to measure flight end. I will fly them tonight and take video.

 

1. Nozzled 3# fuse powder, 125g fuel grain.

2. Nozzled 3# Hybrid, 125g fuel grain.

3. Nozzleless 3# 75:15:10 (no oil) BP, 150g fuel grain.

 

You said as the nozzle gets bigger it will lose thrust but you failed to mention as the nozzle gets bigger so does the burning surface of bp making this point irrelevant..... This is why they have a better thrust curve. As the nozzle gets bigger so does the burning surface area. Making the thurust curve more linear when compared to a nozzled motor. And the linear the thrust curve the better as we all know........

 

The main reason why oil is added to fuel is to make the fuel grain hold its shape make it stronger and more dense which equals more fuel. It also stops fuel from blowing out of the motor. You did not add oil to your motor so it will perform poorly of course.

 

This is also going to be an unfair test however because you are comparing a tuned motor to an UN tuned nozzle less rocket.

[dagabu]

WHY SHUT MY MOUTH!!!

 

This is my reply from Danny Creagan....

 

 

"A 5/8 nozzleless motor will easily carry a 2" salute to 1200 feet. Here is a movie of a 5/8 with a 4" grain and a 3" core (very short - less than LWS), nozzleless, 75/15/10 milled BP (hot, not fuse powder!) with a 2.5" plastic ball filled with kitty litter. A BP spindle would have put it much higher:

 

http://www.wichitabuggywhip.com/fireworks/rockets/nozzleless5eighth...

 

You should be able to lift up to 5" shells with a 3# nozzleless. I've lifted 6" with 4# nozzleless with augmented fuel (BP + 15% whistle).

 

 

A reliable motor to lift 2" salute to 1200:

 

Use either a 5/8 or 3/4 tube

 

Use 75/15/10 BP made with a reactive charcoal. Pine will work, willow or equivalent will be better.

 

Use a BP spindle or, if you just drank the U/T LWS Kool Aid and threw away your BP spindles, you can probably still get it done.

 

Press to at least 4000 so you get a good mechanical binding on the grain. However, you can hand pound these very successfully.

 

Put in about 3/4 to 1 inch of delay using the same fuel. Adjust the delay to get to 1200 - the motor will probably peak, with the correct delay, at around 1500 feet or a tad more. If you want to put it to the moon, then augment the fuel with a little whistle."

Edited September 28, 2010 by dagabu

[Pyropow3r]

Im going to have to pose-pone my efforts on this project for the next 1-2 weeks due to just having a new shed built and the concrete slab be poured just 3 days ago.... I gotta wait for it to cure build benches and move all my stuff in..........

[dagabu]

Soooooo, jealous!

 

I made a kilo of the oiled fuel last night, on my way to the shop to press one right now. If the wind holds, I will get that one and the dry fuel end burner up and on video.

[anapogeetoofar]

If I may offer some input on this subject from an experimental rocketeer's point of view, I think I could be of some help.

 

First of all, nozzle less motors, no matter what the burn rate of your propellant is, have regressive thrust curves. As the propellant burns, the KN ratio decreases, meaning the ratio of the available burn area to the nozzle throat decreases, along with thrust.

The decrease in thrust can be quite dramatic, burnsim has given me graphs that shoot straight up, then straight down in fractions of a second, but It can also be just as gradual as a nozzled motor with a regressive thrust curve, such as one using the "tablet" grain geometry.

 

As far as me and the other folks who have investigated nozzle less motors can tell, the ISP is in fact lower when compared with a good convergent/divergent nozzle. You don't even need to actually make and test a nozzle less motor to see it will be less efficient.

 

 

The real fun in nozzle less motors is the high KN's you can use, and the low risk of CATO. DJ's 1# nozzle less has an initial KN of 64 (assuming the core is 3 inches long, can someone correct me?), halfway into the burn, the KN is about 20, we can do better! If the core is 4in long, that 20 becomes about 39, and the initial KN is 80. At 5 in, the KN is nearly 100. In a nozzled motor, using hot BP, an initial KN of 100, with a final KN of 213, probably means CATO.

 

I have made a nozzle less BP motor with an initial KN of about 110, it was a 7/8 diameter grain, with a 1/4 core, probably a bit over 5 in long. No Idea how much thrust it produced (probably somewhere well over 8 lbs), but it managed to get my little aspire the highest I have ever seen it go. It also spat a chunk of grain out (erosive burning is a bad habit of nozzle less motors), the high pressures probably didn't help either.

These were all pressed by the way, if you ram these half of you're propellant will fly out nozzle(that's been my experience at least).

 

Far higher KN's can be used if R candy or an epoxy based propellant is used, why? Because the web thickness of the grain effectively becomes the thickness of you're casing! That means, for a period of time in the burn, some serious pressures can be had. especially with the epoxy propellants, as they tend to be very strong and resistant to fracture. The erosion is ridiculous though unfortunately (bye bye high ISP!) especially with BP motors. I suppose AP could be the best because of its very low elastic modulus (it is rubber after all!) but the erosion would probably be a killer.

I think this is what Ray Goodson was going for with his AP nozzle less experiments.Though he was using ablative nozzles made out of HTPB, the concept is pretty much the same.

 

Another nice ting is you can use propellants with scary pressure exponents. A guy at NEFAR has been researching a KClO4/epoxy/Mg propellant with a frighteningly high Mg content. He wants it for end burners, I have never seen a single one of his motors with that propellant work, it has worked for him......a few times (or so I'm told). Next launch (Oct 9 I think?) I'll get the formula from him and try it in a nozzle less, should be interesting.

 

Ill throw some videos of static tests up when I get a chance.

 

 

I hope some of that was helpful to somebody, I only started venturing into pyro a few months ago, so I have yet to see how useful my rocketry experience will be.

[dagabu]

First of all, let me officially state that I hate Pyropow3!

 

 

I am just kidding of course. I pressed three oiled nozzleless rockets this morning and BOY OH BOY are they pretty! The grain is so hard that I could not scratch it with my fingernail. I have some strobe stars drying right now for the headers I will be using on top (small 2" canisters) of them.

 

AATF, good to see you hear, I am an old APCP fan but the cost and set up not to mention the shooting sites and waivers needed were too much for me and when the ATF struck the fuel as explosive, well, I quit the field all together. I am only doing pyro now with a major in rockets.

 

I am a n00b here but I like to debate way too much to stay silent very long.

 

Anyone that has not tried nozzleless has at least got to try it. My tooling Loves me now No scratches from clay nozzles.

[Pyropow3r]

First of all, let me officially state that I hate Pyropow3!

 

 

I am just kidding of course. I pressed three oiled nozzleless rockets this morning and BOY OH BOY are they pretty! The grain is so hard that I could not scratch it with my fingernail. I have some strobe stars drying right now for the headers I will be using on top (small 2" canisters) of them.

 

AATF, good to see you hear, I am an old APCP fan but the cost and set up not to mention the shooting sites and waivers needed were too much for me and when the ATF struck the fuel as explosive, well, I quit the field all together. I am only doing pyro now with a major in rockets.

 

I am a n00b here but I like to debate way too much to stay silent very long.

 

Anyone that has not tried nozzleless has at least got to try it. My tooling Loves me now No scratches from clay nozzles.

 

What reasons can you possibly give to hate me........... was it my corrections ?

[dagabu]

What reasons can you possibly give to hate me........... was it my corrections ?

 

LOL!!! Pyropow3, it was tongue in cheek! Heck no, I'm not angry, I'm glad you stuck to your guns and made believer of me.

 

I am just kidding of course.

 

Now that we are buddies.... got any more rocket ideas?

[Updup]

What reasons can you possibly give to hate me........... was it my corrections ?

 

I think its the fact that we are all really jealous of your new shed, any cool features you going to put in it?

 

Or the fact the he sees the light in nozzless rockets now... not sure.

[dagabu]

Yup, UpDUp got it!

[Pyropow3r]

^^^^^^Yup Rodger all that ^^^^^^^

 

Now just got to wait till the shed is done then I can start making some real monsters !!!!!!!

 

Until then stay safe ........

[Pyropow3r]

OK Im back with my new shed and here is where i am on the subject of nozzle-less rockets.....

 

I constructed a nozzle-less rocket with oil added to the fuel to help with the grain formation but adding oil has one fatal flaw it slows down the burn rate excessively ...... It slows down the burn rate so much you will need an extremely long core for them to work properly so long that it is probably better to not add oil to the fuel and make a shorter core thus making construction more feasible.

 

Sure some of the fuel will get spat out of the motor with no oil added but its all worth while because you dont need to make an excessively long core. so my tips are don't use oil

and oil would make a great burn rate depressant (better than using bicarb-soda)