Questions on 8oz. Bp coreburning rocket tooling.

[Paradise]

I've got 8oz. tooling from Wolter pyro. The TOTAL length of the entire spindle from base plate is 5 1/4". My question is if I cut my tubes at 6 1/4" as is suggested and use a bulkhead of 1 increment that only leaves 3/8" on top of the spindle!?? In my limited experience that does not seem correct. So I've been cutting tubes at 6 1/2" - 6 3/4" (max). Is this the norm?

[Paradise]

Needless to say (but I will anyways☺) the no PASS lines are not going to aid in any type of consistency.

[Paradise]

Btw, my fuel comp is 60/20/10 (bp)

[NeighborJ]

I believe it is all personal preference as to lengthening your tube length but it appears that Wolter intends for you to use a slower delay comp without a bulkhead.

I use a 50/50 delay mix of bp and titanium dioxide which has a burn rate of 1 second per 1/8". So if I were pressing a motor on this spindle I would use 5/16" thick increment of fuel on top of spindle then 3/8 increment of delay with no additional bulkhead. This will allow for a 5/16" thick cavity on top for passfire fusing and I can still use the factory no pass lines on the rammers. The other option is to just use a sharpie to mark new no pass lines for longer tubes.

Something seems wrong with your fuel mixture(60-20-10) doesn't add up. It would be about 67-22-11 by percentage at that ratio . I'd start at 65-25-10 and swap the kno3 and charcoal 5% at a time until you get the performance you are looking for. Raising the sulfer content above 10% has never created any benefits for my motors and only robbed my motors of gas producing charcoal.

[dagabu]

Something seems wrong with your fuel mixture(60-20-10) doesn't add up. It would be about 67-22-11 by percentage at that ratio .

 

Often comps are measure out in parts, not a 100% ratio.

[Paradise]

Titanium dioxide I'm not familiar with, being a newbie and all. I've been using winokur 20 as delay. Seems if I don't ram an increment of hot fuel above the spindle followed by an increment of delay then the payload bursts too low. Is 100-120 grams too heavy ya think? Btw THANK YOU very much for your time/reply!

[Paradise]

What's the point of the bulkhead then??

[NeighborJ]

Titanium dioxide is a white pigment used in paint. I'm not aware of many people who use it. Baking soda will work just as well. The W#20 works well also and it has a tail. I'm just partial to the titanium dioxide because it won't smoke much and after it burns it stays white hot ensuring ignition of passfire fuse. Just some insurance.

The delay comp will act as the bulkhead until it gets consumed and at that point, if your delay is correct, you should be at apogee. If you can lift a given weight to display height then the delay can be adjusted for apogee. Don't forget if you can't get enough delay from the top of the motor ,you can Always use a time fuse in your header.

[dagabu]

I dont use a bulkhead, just delay, the returning stick is much less likely to lawn-dart with a completely empty tube, when clay nozzles and clay bulkheads are used, one should consider a 'stick buster' to separate them.

[NeighborJ]

Dagabu if it is a smaller nozzled bp rocket I don't use a salute to break the stick. I've usually only taped the stick on in two places with two layers of masking tape and layed a piece of visco fuse between the two layers of tape, it separates the stick every time.

This is a pic of a 2 oz ready to fly with stick separators.

[dagabu]

J, that is a WONDERFUL idea! Definitely one of those, "Why didn't I think of that?" moments!!!

[Paradise]

Stick separator, 😉 GREAT idea. So no bulkhead = no suprise lawn darts.. DEF a + in my sitch. So under what circumstances is a bulkhead desirable? Also, will a delay of 50% bp, 50% baking soda burn in an open pile? My rp comes from Danny Creagans site, he suggests 18/6/3. Isn't that the same as 60/20/10? Oh yeah, I added 2 parts 3 micron al also. So increasing kno3 in 5% increments to heat it up -or- 5% increments of charcoal too cool it down. Sounds very straight forward 👍. Will a 5% increment of coarse charcoal say 30-40 mesh cool it down alot more than the same in airfloat? To what extent will heating up the rp increase its payload potential ya think? And please one more quesht: is it hotter bp fuel in smaller rockets for faster gas propagation? Then slower fuel for larger rockets why? Does slower = say... more robust? Therefore greater thrust potential to get that heavy sucker in the air? I apologize if this is a total snore 😴. Once more I am sincerely grateful for those sharing their time and expertise 👍

[Paradise]

NJ, nice little rocket there btw in a small header like that what would be an example of a fairly basic yet neto effect? Including type of burst and the kitchen sink. I'm just trying to get some ideas sprouting. I've done rolled charcoal streamers w and w out metals, parlon bound veline colors, and a few kinds of pumped glitter stars. Mostly cylinder headers 1 3/4"-2" paper and plastic on my 8 oz rockets. FU,UN! 😁

[Paradise]

Btw, I know nothing of rocket science nor pretend to. I'm just trying to wrap my brain around the basics in a way that I can understand. Simply and in laymens terms. So I can have more fun!👍

[NeighborJ]

Umm where to start, safety: please do not ram the AL in your motor even if it is only 5%. It will pose an explosion hazard, unless you use a press, not to mention it will scratch your shinney new tooling. Scratched tooling = stuck spindle😖😞. When you test this motor test it upside down in the ground, unless you have a very large test site that can handle Catos and misguided launches. No headers, at least until you get a consistently reliable result.

The first thing you should concentrate on is getting it to work. The addition of different mesh charcoals will throw in too many variables and it only makes diagnosing any problems that much harder. Stick to only the screen mixed airfloat 60/20/10. The coarse mesh charcoal should be looked at as an effect and while it does add fuel value it's not a good choice of fuel. Most of it burns as firefly dust outside the motor.

The 50/50 baking soda will be a flop if you are not mixing it with hot mill dust. If you are using the screen mix you will need far less soda. I can't pick a number out for you because I don't know your powder. To figure this out, take a weighed amount of your rocket fuel and add say about 20% soda, ram an inch of comp in the tube and test the amount of time it takes to burn to the other end of the grain. Keep adding measured amounts of soda until the burn time of the space you have for delay matches about 2.5-3 seconds. If I remember it was 1 second for 1/8" of delay because you only had 3/8" of room on your motor.

This is a process of experimentation and the goal is to learn principals and techniques which will aid you in all other pyrotechnic endeavours. This is rocket science but it's more like "cowboy style".

Keep us posted.😀

[dagabu]

J, wondering about your statement "please do not ram the AL in your motor even if it is only 5%. It will pose an explosion hazard, unless you use a press, not to mention it will scratch your shinney new tooling."

 

While it's never a good idea to ram any metal on a spindle, why would aluminum cause scratching? 3µ Al is going to have all sorts of coatings on it to keep it from degrading, it should pose no issues for scratching at all. It's the small µ size that causes me concern, not the aluminum itself in ramming, it's non-sparking and non-abrasive. No real friction to be concerned about with small flakes but being reactive as it is, I would keep it to the delay portion.

 

THAT SAID, adding aluminium to rocket fuel increases the burn speed at lower percentages and slows it at higher percentages. It really provides no advantage in the core as the core is exhausted within the first few hundred feet and the delay gives the tail, not the core.

[dagabu]

Stick separator, GREAT idea. So no bulkhead = no suprise lawn darts.. DEF a + in my sitch. So under what circumstances is a bulkhead desirable? Also, will a delay of 50% bp, 50% baking soda burn in an open pile? My rp comes from Danny Creagans site, he suggests 18/6/3. Isn't that the same as 60/20/10? Oh yeah, I added 2 parts 3 micron al also. So increasing kno3 in 5% increments to heat it up -or- 5% increments of charcoal too cool it down. Sounds very straight forward . Will a 5% increment of coarse charcoal say 30-40 mesh cool it down alot more than the same in airfloat? To what extent will heating up the rp increase its payload potential ya think? And please one more quesht: is it hotter bp fuel in smaller rockets for faster gas propagation? Then slower fuel for larger rockets why? Does slower = say... more robust? Therefore greater thrust potential to get that heavy sucker in the air? I apologize if this is a total snore . Once more I am sincerely grateful for those sharing their time and expertise

 

Whats the baking soda for? Lengthening the delay? Why not just use a longer delay increment?

[Paradise]

Will do! Going to test this weekend when I get home. I am VERY concerned about safety therefore, GOOD ADVICE! I assumed (bad idea) The al was fine enough to ram around the spindle w/ out consequence. So in reality metal is metal always to be avoided in that area, got it. I've flown many successful 8 oz. It seems my rp DEF needs more consistency from batch to batch though. When they take off with an extra loud whoosh is when I can tell (mostley) they arent going to go high enough. That's when I start with the rp increment over the spindle b4 the delay and sometimes no delay at all. Nozzeless, 75/15/10 works consistently almost ALWAYS for me, straight up like an arrow but a bit lack lustre. I considered just sticking to it but figured the ability to get consistency WITH a nozzle was par for the course as a good little beginner pyro. I like " cowboy rocket science"😁

I'll keep my endeavors posted. Ty!

[dagabu]

Will do! Going to test this weekend when I get home. I am VERY concerned about safety therefore, GOOD ADVICE! I assumed (bad idea) The al was fine enough to ram around the spindle w/ out consequence. So in reality metal is metal always to be avoided in that area, got it. I've flown many successful 8 oz. It seems my rp DEF needs more consistency from batch to batch though. When they take off with an extra loud whoosh is when I can tell (mostley) they arent going to go high enough. That's when I start with the rp increment over the spindle b4 the delay and sometimes no delay at all. Nozzeless, 75/15/10 works consistently almost ALWAYS for me, straight up like an arrow but a bit lack lustre. I considered just sticking to it but figured the ability to get consistency WITH a nozzle was par for the course as a good little beginner pyro. I like " cowboy rocket science"

I'll keep my endeavors posted. Ty!

 

Try top lighting the rocket, easy way is to wrap a few turns TIGHTLY around a length of visco to block the fire and stuff it all the way up the core with the end bared. They leap off the stand for me.

[Paradise]

D, it's just an (unfamiliar to me) delay comp NJ uses 50/50 ti dioxide, bp. I was just curious about it's characteristics. I will continue w the win 20 but test the burn rate as NJ outlined. 👍

[Paradise]

D, just read ur other post. THAT is something I did Not know. When I top light the rp it seems like it burns up too quick but now I am realizing... Hmmm I have no idea actually what I'm realizing I have to think about that for a minute. I'm at work so if I drift off to much into pyro mode "snap"!! Already past lunch! After work though the wife....well, took a wee bit adjusting and she's used to it now. 😉 tg!

[Paradise]

But I think I've left more than just the tip of the visco bared which would not top light but ignite most of the core as well. I have to use some control I'm thinking about it when I don't even realize it and my task at hand is getting jealous

[NeighborJ]

The delay comp I use is just personal preference. It burns slow at a predictable rate and with almost no smoke or light. The rockets tend to leap off the launcher with a nice flame and then seem to disappear until the burst. Builds anticipation. I use other comps with Fe-Ti, AL flake or plain Ti if I'm using a press and want a glitter but none of them seem to burn at such a predictable rate and in such a short increment 3/8" as the Ti dioxide. That's not to say one doesn't exist, I just haven't found it yet.

The soda in the w#20 can be increased also if it burns too fast.

[dagabu]

It is certainly a personal decision but overall, people want to see the tail all the way to break. It's hard for people to track the flight and they miss the burst, which is more important to some than the spread of the stars.

[Paradise]

Solid on both accounts. This clarification is EXTREMELY helpful to me. Ty!👍