Good BP based rocket fuel

[PyroAce]

I did a search but could not find anything specific to my enquiry. Currently I only have access to airfloat Charcoal, what would be a good Potassium Nitrate/Sulfur/airfloat Charcoal based formula for core burner rockets (1LB). In the past I made smaller rockets with coarser Charcoal that worked quite well (mind you they had no header), but I cannot remember the formula, I'm pretty sure if was a formula from Brocks book.I believe the addition of coarser Charcoal (as most rocket formulas stipulate) is primarily to add to the effect of the rockets tail and of slowing the fuel down. What would be a good formula using airfloat Charcoal, can I just substitute the coarser Charcoal with the airfloat Charcoal, or does someone have a proven rocket fuel that uses airfloat charcoal only? Last thing I want is constant CATO from too fast burning fuel.

 

And while I am on rockets, what kind of metals give good effects that I can add straight to the formula, I know iron comes out good, but must be coated, how does Aluminium fair in a rocket?

 

 

[pyrokid]

I have succesfully used a 6/3/1 (KNO3, Charcoal, Sulfur) formula with commercial airfloat, but I believe that some guys have had that CATO on them. It may depend on how you process your fuel.

 

If you are afraid of blowing them up, start with a slightly more conservative fuel and then begin increasing the amount of KNO3 for more power.

 

I don't have all that much experience with tails, but ferro titanium or titanium added to the delay is very nice.

 

Good luck!

[dagabu]

I did a search but could not find anything specific to my enquiry. Currently I only have access to airfloat Charcoal, what would be a good Potassium Nitrate/Sulfur/airfloat Charcoal based formula for core burner rockets (1LB). In the past I made smaller rockets with coarser Charcoal that worked quite well (mind you they had no header), but I cannot remember the formula, I'm pretty sure if was a formula from Brocks book.I believe the addition of coarser Charcoal (as most rocket formulas stipulate) is primarily to add to the effect of the rockets tail and of slowing the fuel down. What would be a good formula using airfloat Charcoal, can I just substitute the coarser Charcoal with the airfloat Charcoal, or does someone have a proven rocket fuel that uses airfloat charcoal only? Last thing I want is constant CATO from too fast burning fuel.

 

And while I am on rockets, what kind of metals give good effects that I can add straight to the formula, I know iron comes out good, but must be coated, how does Aluminium fair in a rocket?

 

 

 

Everyone here that has made rockets can tell you that rockets are finicky little buggers that depend on many variables that together make a rocket succeed or fail.

 

To be 100% safe, go for a nozzleless design with 6/3/1 as already mentioned. Top fuse for thrust and make sure to use an NEPT tube, and press to 6000LPI.

 

Add a nozzle and its all up for grabs. I find in my own experiences that even a simple change of manufacturers of a single component can have drastic results.

 

Yes, adding 5% 80 mesh charcoal will slow the fuel down and is a great way to dial in a fuel that is too hot and CATOs. I am of the opinion that the only metals that should ever be rammed should be on top of the spindle and not added into the fuel that is on the spindle. 1. Ti and Fe will scratch the spindle when the spindle is removed. 2. The friction created by metal to metal contact is thought to be a leading reason for motor ignition when building them. I suggest that you make a separate tub labeled "Delay" and add your metals to the fuel you are using in that tube but only use it above the spindle. Aluminum works OK in delay but is not nearly as noticeable as Fe or Ti.

 

With 10-15% metals in the delay, the tail should appear full.

 

-dag

 

 

 

Edited February 20, 2012 by dagabu

[Peret]

I use 60/30/10 with commercial airfloat, but it does need to be ball milled. I keep a tub of commercial airfloat just for this purpose, as it seems to be quite consistent. Without milling, it's feeble and can hardly lift its own weight, but a good milling transforms it. I use it for both 4oz and 1lb cored motors, with nozzles. My current favorite mix substitutes 8% coarse flake aluminum for part of the charcoal, ie 60/22/10/8. It gives a good silver tail.

[californiapyro]

dag, nozzleless with 6/3/1? seems like that wouldnt lift at all....

 

how do you feel about ramming aluminum around the spindle?

[dagabu]

dag, nozzleless with 6/3/1? seems like that wouldnt lift at all....

 

how do you feel about ramming aluminum around the spindle?

 

Like Peret spoke to, a good ballmilling is needed to get the fuel to be reactive and then a top fusing of the core is necessary to generate the volume of gas you need for thrust. You don't want any delay. I prefer 75/15/10 for my rockets but I also encounter the occasional CATO with nozzles. The same rocket will fly very well one day and CATO the next even though they were made identically on the same day with the same batch of fuel.

 

I don't recommend any metals around the spindle at all.

 

My method of choice right now is 4 increments of benzo whistle followed by BP with 3 increments of BP with 20% Fe for delay. no nozzle and still jump off the rack but at 1/3 the cost of a full benzo whistle motor.

 

-dag

[nater]

Dag, are you using U/H tooling with those?

[dagabu]

Yup, I do.

 

-dag

[allrocketspsl]

ok hold on I was under the impression you needed the hottest fuel for nozzeless as the only time I made them was with the same fuel I use on mt long tailed cored rockets.It litfted but slowly then took off.I have now 3lb moters to be made using hot 75/15/10 and using Al's paulowania charcoal w/airfloat.Milled it for 5 hours its hot.Going to 1 percent oil.All

[dagabu]

ok hold on I was under the impression you needed the hottest fuel for nozzeless as the only time I made them was with the same fuel I use on mt long tailed cored rockets.It litfted but slowly then took off.I have now 3lb moters to be made using hot 75/15/10 and using Al's paulowania charcoal w/airfloat.Milled it for 5 hours its hot.Going to 1 percent oil.All

 

Well.... Mostly true. Here is the deal, if you want to lift any real weight, you have to use a fast fuel but my PGI opening ceremony red rockets lifted a 10g report just fine to 600-700' but rose slowly from the rack. This fuel will just not lift the rocket motor itself if lit at the end, it must be lit all the up in the end to make enough thrust. I have found that the reason a lot of nozzleless rockets CATO is because of the top lighting and once a fuse is set at the end of the motor, the rocket will fly just fine. I pipe quick match all the way to the end of the spindle to accomplish top lighting.

 

-dag

 

 

 

[PyroAce]

Thank you everyone for the replies. In regards to adding metals to the formula, only use them in the delay, in saying this though, how much will this add to the rocket flights effects, the delay will last around 3 seconds correct, this will be at the rocket flights apogee, is it worth doing?

[optimus]

Thank you everyone for the replies. In regards to adding metals to the formula, only use them in the delay, in saying this though, how much will this add to the rocket flights effects, the delay will last around 3 seconds correct, this will be at the rocket flights apogee, is it worth doing?

 

The delay should start burning up before apogee so you will see the effect. Different people have different tastes, but if you like a tailed rocket it's well worth doing.

[PyroAce]

The delay should start burning up before apogee so you will see the effect. Different people have different tastes, but if you like a tailed rocket it's well worth doing.

 

 

I will have to give it a try, you won't know if you like something until you try it, this is very true. I mainly want to use Aluminium because it is a lot cheaper than Titanium, any suggestions on a good size mesh Aluminium and formula to use as a delay?

[allrocketspsl]

I will have to give it a try, you won't know if you like something until you try it, this is very true. I mainly want to use Aluminium because it is a lot cheaper than Titanium, any suggestions on a good size mesh Aluminium and formula to use as a delay?

 

use sperical 325 mesh aluminum mate put it in the delay only if you want a sparky tail to your CORED rocket!! Depending on what header your using the timing you have to dial it in using the delay.On one pounders that I shoot I use c6 with 325 mesh sperical al one incremen just above spindle,me to no need to use TI but I do use FeTi sometimes for different look!I cant tell you how to on end burners or nozzeless.Im making 3Lb motors nozzelesss as I type for a couple of specialty headers so Im in the dark on this subject also.Good luck.The more you make and shoot the better you get. ALL

Edited February 22, 2012 by allrocketspsl

[dagabu]

I will have to give it a try, you won't know if you like something until you try it, this is very true. I mainly want to use Aluminium because it is a lot cheaper than Titanium, any suggestions on a good size mesh Aluminium and formula to use as a delay?

 

There are three things to consider when adding delay above the spindle.

1. Will the delay increments hold the pressure of the rocket motor or will it blow out?

2. What delay timing are you looking for?

3. What is the ID of your motor?

 

When you get to #3 motors, the 1" of delay above the spindle (BP burns at about 3 seconds per inch in column) will blow out (in my experience) and more delay will cause to much coasting time allowing the rocket to lean over or even come back down before going off. In a #1 motor, 1" of delay (BP) seems to work fine, it also gives you 3 seconds of flight and the heading goes off right about where it should. There will be a lot of testing on your part unless you are willing to do as those whom have already tried and failed.

 

What is the point of metal in the delay? Tracking... Rockets may coast for several seconds until their heading breaks and it is very easy to lose sight of the rocket in that coast phase, the metals help you to keep track of the trajectory and give you a better chance to view the whole shell display.

 

-dag

[PyroAce]

Thank you to everyone for the advice

 

I launched my first 1LB rocket and it was a CATO, but I am kind of happy which might seem strange to a few, I am happy because I was able to retrieve the casing so I can get an idea why it failed. What happened was the rocket lit up and launched into the air perhaps 10-15 meters, it then made a louder whooshing sound and gave a soft explosion. I looked around and found the casing still intact with the stick still attached. On further inspection I have found that the clay washer is still intact, but interestingly the top clay plug was gone, so it couldn't hold the pressure. How thick should I be making this clay washer? I believe that I may not have given this top clay plug enough hard blows, I underestimated the pressure these rockets can produce.Realistically was my rocket failure even really a CATO? Isn't a CATO more related to the rocket motor exploding before is even launches?

 

 

[dagabu]

Thank you to everyone for the advice

 

I launched my first 1LB rocket and it was a CATO, but I am kind of happy which might seem strange to a few, I am happy because I was able to retrieve the casing so I can get an idea why it failed. What happened was the rocket lit up and launched into the air perhaps 10-15 meters, it then made a louder whooshing sound and gave a soft explosion. I looked around and found the casing still intact with the stick still attached. On further inspection I have found that the clay washer is still intact, but interestingly the top clay plug was gone, so it couldn't hold the pressure. How thick should I be making this clay washer? I believe that I may not have given this top clay plug enough hard blows, I underestimated the pressure these rockets can produce.Realistically was my rocket failure even really a CATO? Isn't a CATO more related to the rocket motor exploding before is even launches?

 

 

 

A #1 rocket needs a 1" delay in order to hold the pressure of BP fuel with no bulkhead (the washer) and it has to be pressed to a substantial pressure as well. Hand pounding rarely creates enough pressure to keep the delay in place and so a clay plug is often used to support the delay so it doesn't blow out.

 

You really didn't have a CATO but a blown bulkhead, try more delay (faster burning so as to not have around trip) next time.

 

-dag

[ibizon]

Thank you to everyone for the advice

 

I launched my first 1LB rocket and it was a CATO, but I am kind of happy which might seem strange to a few, I am happy because I was able to retrieve the casing so I can get an idea why it failed. What happened was the rocket lit up and launched into the air perhaps 10-15 meters, it then made a louder whooshing sound and gave a soft explosion. I looked around and found the casing still intact with the stick still attached. On further inspection I have found that the clay washer is still intact, but interestingly the top clay plug was gone, so it couldn't hold the pressure. How thick should I be making this clay washer? I believe that I may not have given this top clay plug enough hard blows, I underestimated the pressure these rockets can produce.Realistically was my rocket failure even really a CATO? Isn't a CATO more related to the rocket motor exploding before is even launches?

 

 

 

I was in this same spot a year ago. Wanting to make my first rockets ever, I prepared about eight 1lb BP rockets for a club shoot and everyone of them either blew up before launch, or made it about 20-40 feet in the air before blowing up. I used a variety of fuels, ranging from 60-30-10 up to 75-15-10, so I could see which one worked best. In my case, the problem wasn't the fuel, but rather the way it was prepared. I was putting 5 parts dextrin and then granulating it to keep down dust. It did a good job of keeping down the dust, but since I was ramming my rockets, I was unable to apply enough pressure to completely break up these grains of fuel. This left tiny cracks between the grains leading up to my header. I came to this conclusion based on the fact that not a single motor casing was destroyed, only the header. I eliminated the Dextrin from my fuel and have only had one CATO since then. It doesn't sound like this is your problem though.

 

As a rule, when I use a bulkhead (the clay washer), I make it approx 1/2 ID of the rocket motor, so 3/8" in the case of the 1lb motor.

 

My technique:

 

I use universal tooling and no longer use nozzles in my rockets because they perform well enough for me the way they are.

I ram a 75-15-10 fuel to 3/8" above the spindle.

Next comes 3/4" to 1" of delay.

then 3/8" bulkhead (I rarely do this either)

 

Depending on what I'm lifting, I'll just j-hook some visco inside, or attach some fast fuse to the end of the visco and feed it up the core. The latter gives me a faster take off or allows me to lift slightly heavier headings.

 

Hope this some of this helps.

[PyroAce]

Thank you for the advice dagabu & ibizon , I will try the suggestions out.

[WonderBoy]

I am a big proponent for using clay bulkheads. I use them in every motor that I make, as it gives extra insurance against blowing through, and it allows you to use a slower burning delay ie. star compositions.

I like Chrysanthemum #6 plus about 10% mixed mesh flake Al

and Blonde Streamer which uses FeTi

I ram all of my BP motors and I make them pretty hot, so I find a clay bulkhead to be necessary. For a bulkhead in a 1lb motor I use a heaping tsp. of clay. Are you ramming these? If so, what size and type of mallet are you using?

 

 

WB

Edited March 12, 2012 by WonderBoy

[dagabu]

I am a big proponent for using clay bulkheads. I use them in every motor that I make, as it gives extra insurance against blowing through, and it allows you to use a slower burning delay ie. star compositions.

I like Chrysanthemum #6 plus about 10% mixed mesh flake Al

and Blonde Streamer which uses FeTi

I ram all of my BP motors and I make them pretty hot, so I find a clay bulkhead to be necessary. For a bulkhead in a 1lb motor I use a heaping tsp. of clay. Are you ramming these? If so, what size and type of mallet are you using?

 

 

WB

 

I used to as well but the last 50-60 rockets I made (#1) have been nozzleless with no bulkhead. The issue is the weight of the empty rocket coming back down. An empty paper tube on a stick does little damage but a clay nozzle and a clay bulkhead give it enough weight to break a windshield.

 

-dag

[allrocketspsl]

when i was shooting in my backyard I got so good that hot gluing slightly the stick on when the shell broke it blew off so the tube seperated and no damage,yeah i hit my own car twice no damage i could fire a one pounder have it break right over the house when it blew back from the break all laned i used sticks four or five times

[WonderBoy]

Yes this is a risk. A general rule of thumb that I follow is the only thing inside of the fallout zone is myself. At club events this becomes an issue and I don't want anyone or anything to be hit and risks should be minimized. But as I see it, anyone at the event that places themselves or their cars inside the fallout zone of a BP 1lb motor should already understand the risks and consequences of doing so, it is all part of the fun.

 

On another note, in my early days I had a nozzle-less and bulkhead free 1lb BP motor (pulpy tube) come back and land on the deck, leaving a nice 1/4" deep ring indent in the wood, not something I particularly want to get hit with. From my experience, and what I have observed, as long as the tube is still attached to the stick, it is pretty likely to become a lawn dart, even if it is a half ounce lighter, missing the nozzle and bulkhead material.

 

 

WB

Edited March 13, 2012 by WonderBoy

[dagabu]

Yes this is a risk. A general rule of thumb that I follow is the only thing inside of the fallout zone is myself. At club events this becomes an issue and I don't want anyone or anything to be hit and risks should be minimized. But as I see it, anyone at the event that places themselves or their cars inside the fallout zone of a BP 1lb motor should already understand the risks and consequences of doing so, it is all part of the fun.

 

On another note, in my early days I had a nozzle-less and bulkhead free 1lb BP motor (pulpy tube) come back and land on the deck, leaving a nice 1/4" deep ring indent in the wood, not something I particularly want to get hit with. From my experience, and what I have observed, as long as the tube is still attached to the stick, it is pretty likely to become a lawn dart, even if it is a half ounce lighter, missing the nozzle and bulkhead material.

 

 

WB

 

Two observations:

 

1.) A "good" BP rocket with ample delay and a small heading can easily go 1000' vertical and 2000' at the optimum angle of flight. Even the PGI does not have these distances cleared for fallout. Any rocket at any time can take a 90° turn and come right for the observers, 2000' is well within windshield territory at any shoot site I have ever been at.

 

2.) I have seen rockets with and without nozzles and bulkheads hit items and the damage even an ounce of head weight can make is remarkable.

 

I do agree with your statement, "But as I see it, anyone at the event that places themselves or their cars inside the fallout zone of a BP 1lb motor should already understand the risks and consequences..." though and do see it as an acceptable risk for those that partake in rocketry but this is not always the case and innocent bystanders (children and such) can be injured by rockets that are allowed to become lawn darts. this is why I have worked hard to place the stick against the shell bottom causing the hot glued (only, no tape) stick to be ejected from the tube in most cases or add a small report to shred the tube and eject the stick.

 

It is likely that this will be the standard in the near future with the guild as rockets landed in excess of 1500' away from the racks consistently. This is the West Fargo Fairgrounds, it is 1500' to the highway from the closest rocket rack.

 

 

 

 

This is one of about 100 rockets stuck in excess of 6' in the ground because they didn't uncouple and had clay nozzles and bulkheads. No tube/stick combos were found out this far that were still vertical stuck in the ground Friday morning after "Rocket Thursday". This stick/casing combo was on the near shoulder of Hwy 94 at the point where the Interstate 94 badge is shown in the picture above on the bottom left. There were several on the far side of the freeway as well.

 

 

 

Now lets consider the audience that was sitting 1000' away to the North... I don't think anybody there knew of the consequences an errant rocket would have, do you think they did?

 

 

 

 

I think its better to de-stick.

 

-dag

Edited March 13, 2012 by dagabu

[PyroAce]

I am a big proponent for using clay bulkheads. I use them in every motor that I make, as it gives extra insurance against blowing through, and it allows you to use a slower burning delay ie. star compositions.

I like Chrysanthemum #6 plus about 10% mixed mesh flake Al

and Blonde Streamer which uses FeTi

I ram all of my BP motors and I make them pretty hot, so I find a clay bulkhead to be necessary. For a bulkhead in a 1lb motor I use a heaping tsp. of clay. Are you ramming these? If so, what size and type of mallet are you using?

 

 

WB

 

 

Yeh I am ramming them, I used a rubber mallet, I hit the rammer fairly hard and around 8 times, but to be honest I probably could have hit it harder. I will try again, trial and error is all part of the fun and nothing is more rewarding than when you get success,