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First rocket tested with new tooling, failure. Options?


Phil

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I finally got around to ramming a nozzless rocket a few days ago and tested it early this morning. It was probably about the saddest rocket launch I've seen apart from the challenger itself. It was rammed with 100# screen mixed 75/15/10 using commercial airfloat. Then granulated with lacquer thinner and mineral oil +3%. It had a heading I filled with baking soda as an inert charge to be on the safe side in case it decided to go sideways. There was about 30 grams of my inert charge in the heading. I noticed upon completion how heavy the rocket felt and I was skeptical it would be able to lift the heading. It left the pipe a few feet very slowly before turning sideways and ending up about 10 yards from the launch site. It was kind of funny to see so it wasn't all bad I guess. The completed rocket stick and all weighed just over 4 ounces if I recall correctly. These are the motor tubes I'm using. https://www.woodysrocks.com/store/p218/%22Cohete%22_Tubes_-_5%2F8%22_ID_x_4%22_-_50ct_.html#/

 

I'm trying to see where I can go from here to get a successful rocket, without spending more money.

I was thinking the following...

 

-cut weight of heading powder charge in half

-leave out the mineral oil for the next batch of fuel (someone suggested this in an earlier thread)

-use better charcoal (someone suggested this in an earlier thread)

-adjust ratio of ingredients (Anyone have experience experimenting where the only variable they change is ratios?)

 

I actually already got started on #3, I stuffed a paint can full of my ERC pet bedding poked a hole in the lid then sit it in a propane grill. After running it through a coffee grinder I used the portion that passed my #100 screen and dumped the rest back in the bag. I used it to make another batch of BP the exact same way I did last time, the only difference being homemade ERC charcoal instead of commercial air-float. Here are the results.

 

Do you guys think this would be a significant enough difference to help, of course paired with reducing the weight of the heading and leaving out the oil?

Edited by Phil
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The skepticism of the novice is not worth so much. I would seek to establish a baseline of performance without adulterants such as oil or lacquer thinner. Typically, nozzleless rockets can handle very hot fuel. Unmilled fuel with commercial charcoal is not quite there. You might try a nozzled motor with 65/25/10 fuel on that tooling. A 0.625" motor should lift 30g with no problems.
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Hi Phil. Your ERC bp version looks more promising. Cutting the overall weight will also help. You may as well give it a go.

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The skepticism of the novice is not worth so much. I would seek to establish a baseline of performance without adulterants such as oil or lacquer thinner. Typically, nozzleless rockets can handle very hot fuel. Unmilled fuel with commercial charcoal is not quite there. You might try a nozzled motor with 65/25/10 fuel on that tooling. A 0.625" motor should lift 30g with no problems.

Thanks for the recommendations. I just finished granulating this new batch with alcohol and left out the oil and it certainly looks better than the old stuff I was using. After doing a rocket with this I'll certainly be trying out that ratio. If that doesn't do it I have the kitty litter.

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Looking forward to your new test.

 

btw. I had to laugh about your rocket that took off, then went sideways. Years back my brother and I did some bp rocket tests. The motor (bp end burner) was inserted into a full on rocket design with nose, fins, launch rail, etc.

 

The thing took off slowly with such beauty and grace, for about 20ft, then leaned over sideways and proceeded completely horizontal for hundreds of feet. Like some sort of cruise missile. It was fantastic!!! Not what we wanted, be we still talk about that test with reverence. You can't do that if you tried. :)

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Looking forward to your new test.

 

btw. I had to laugh about your rocket that took off, then went sideways. Years back my brother and I did some bp rocket tests. The motor (bp end burner) was inserted into a full on rocket design with nose, fins, launch rail, etc.

 

The thing took off slowly with such beauty and grace, for about 20ft, then leaned over sideways and proceeded completely horizontal for hundreds of feet. Like some sort of cruise missile. It was fantastic!!! Not what we wanted, be we still talk about that test with reverence. You can't do that if you tried. :)

I stuck one in the muddy riverbank in the middle of winter with a super flimsy stick. When it fired it bent completely over and went UNDER the water and then traveled a good 30ft to the other side of the bridge and then the report went off all under water. It was at night so it looked like a lighted torpedo as it went down river. I never have the camera when something like that happens

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Success! Used the ERC BP and while I don't entirely feel certain this will lift a 30g charge it lifted the 15g inert charge I put in it. Pretty much went up without turning (until after apogee) even though it was a little sluggish compared to some of the other rockets I've seen here. It didn't seem to go that high but it went up sufficiently for a heading to go off IMO so I'm making progress. I'll make another batch of fuel using the ratio suggested earlier and if I see an improvement I think I'll be happy.

 

Unfortunately I had a problem ramming, it was very hard to get the fuel to consolidate into the motor. Every time I removed the tooling the powder would fall out freely. I tried wetting it with alcohol and while that did help a little bit the benefit was offset by the powder clumping up in the hollow rod. I got pretty frustrated and ended up making a nice bulge in the middle of the motor damn near splitting it. Still didn't CATO, these style of rockets are bulletproof lol. It's easy to consolidate with the solid rammer though, just having problems consolidating with the hollow one.

 

 

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Dampening the BP with 3% water by weight will make for much better consolidation. Alcohol is practically useless in that regard. Damp powder isn't so easy to get into such a small diameter tube, so a really steep funnel is helpful.

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Dampening the BP with 3% water by weight will make for much better consolidation. Alcohol is practically useless in that regard. Damp powder isn't so easy to get into such a small diameter tube, so a really steep funnel is helpful.

Will be using water to damp it next time then rather than alcohol. Got a nice set of metal funnels but didn't realize till I got them home they were practically useless because there's a little "lip" right before the neck that tends to catch powder. See if I can knock that off using a dremel.

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Made a large batch of the good powder last night and upon testing it discovered it performed poorly compared to the prior powder. I must have made an error weighing the chemicals out and i had to add more charcoal in the middle of mixing due to some of the weighed out charcoal being too coarse. I also didn't let it dry long enough so I ended up seeing liquid come out the rocket as I was ramming it. I thought for sure this was gonna look like my first rocket but it actually performed really well. I'm sold on making nozzled rockets. I love the wiggle room. it only takes a few seconds to ram one increment of litter and the crutch of the nozzle will probably allow me to use my commercial airfloat instead of having to process the ERC which I'm finding most of what my coffee grinder is giving me is not fine enough.

 

I muddied up my tooling in the process though. Is it okay if I use my pistol cleaning kit with the copper/bronze/brass brush to clean it out? It actually fits perfectly. I know not to use a steel brush inside but I'm not sure how hard the other materials are compared to aluminum.

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Success! Used the ERC BP and while I don't entirely feel certain this will lift a 30g charge it lifted the 15g inert charge I put in it. Pretty much went up without turning (until after apogee) even though it was a little sluggish compared to some of the other rockets I've seen here. It didn't seem to go that high but it went up sufficiently for a heading to go off IMO so I'm making progress. I'll make another batch of fuel using the ratio suggested earlier and if I see an improvement I think I'll be happy.

 

Unfortunately I had a problem ramming, it was very hard to get the fuel to consolidate into the motor. Every time I removed the tooling the powder would fall out freely. I tried wetting it with alcohol and while that did help a little bit the benefit was offset by the powder clumping up in the hollow rod. I got pretty frustrated and ended up making a nice bulge in the middle of the motor damn near splitting it. Still didn't CATO, these style of rockets are bulletproof lol. It's easy to consolidate with the solid rammer though, just having problems consolidating with the hollow one.

 

 

I don't know if this helps much ,but i never made motors without a support and a hydraulic press,PVC pipe and hose clamps are your friend. I also never tried ramming without some sort of additive like 2% mineral oil or granulating first to avoid a face full of dust every increment,this is my least favorite part of ramming fountains currently because it ejects dust every increment. As far as tooling getting muddled up,I feel like it's the most common part of pressing.Every increment and i am usually digging something out of the rammer,i dont think its avoidable.I have to sweep and clean every time i make motors.You just gotta learn to work with it.

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@Phil. There was improvement in the last two tests. It was was difficult to see properly though, because of the video.

If you are just into rocket motors, then I suggest looking into sugar rockets motors. Can be fun and possibly easier to make.

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This is what i did,BP pissed me off when it never performed the same for me because i didn't know what i was doing. I went to hotter fuels that just worked without any tinkering,however I eventually realized its a step that couldn't be skipped for very long. Looking back i might have did it different..

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"crutch of the nozzle"??? That's like the crutch of having tires on the wheels of your car. Jeez.

Edited by davidh
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I swear, I will never understand the attraction to a nozzleless BP rocket. Just, why???

I like nozzleless rockets because they can lift more than standard BP rockets. A 1# nozzled BP motor can reliably lift a 3" shell. A 1# nozzleless motor with good BP can easily lift a 4" shell more than high enough. I like both.

 

That said, it's probably best for a new rocket maker to start with nozzled black powder rockets, especially if hand ramming. The materials are easier to prepare, the slow whoosh is very satisfying, and the nice bushy tail gives a sense of accomplishment.

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I've never made a nozzleless BP rocket, but I thought it would be easier to make having no nozzle to worry about?

A lot of initial thrust to launch a shell would also be a benefit.

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I switched to nozzleless rockets with the hottest BP I could make after this debacle. This was pressed not rammed and you see what still happened. Nozzled rockets are finicky.

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Spectacular!! Sometimes those are more entertaining than the normal flight.

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I switched to nozzleless rockets with the hottest BP I could make after this debacle. This was pressed not rammed and you see what still happened. Nozzled rockets are finicky.

I can't stop laughing because of what he said. I couldn't count how many times i said that after i got all excited and lit something.

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  • 2 weeks later...

Made the motor with the 30g heading using the airfloat charcoal. Got the delay dialed in nice.

https://streamable.com/pxcv54

 

Here's another one with the ERC charcoal lifting 100 grams of fun powder. I made the motor the same way as the one with the smaller heading without taking into account the hotter fuel, so it broke a bit sooner.

https://streamable.com/ykbmav

 

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  • 4 months later...

If you can make hot BP, I don't see why you wouldn't make nozzle-less rockets?! Different strokes for different folks and all that.

 

If you can make hot BP, the hotter the better, there is no dialing them in like with a nozzle. With a small 5g header of flash to help find it in the sky, they take off so fast it's easy to not see it. I was making hot BP already and found one thread on the newsgroups by the 'inventor' and after reading about it gave it a try. Back then just about everyone I talked to about it said I was full of sh*t and there was no way it would work. So I kept it to myself and had a lot of fun with them. Anyways...

 

Also, something sounds wrong if your ERC charcoal is mainly too coarse after going thru a coffee grinder. The shavings should be like a potatoe chip and crumble to dust between your fingers. If too coarse, I imagine it's not being completely cooked and still woody. If using a retort you should cook it until flame stops, then watch for smoke to completely stop, then cook another 4 or 5 min just to be sure. And if you are really pressing the shavings in, then you should shake or stir it a couple times during the cook as the outer cooked stuff can insulate the middle and sometimes its still a white shaving if you really pack it in.

 

When I was using a retort I found the easiest thing was to find the lightest 2x4 in the pile and cut them about an inch shorter than my can. Then take a hatchet and split into 1/4" to 3/8" square kindling and jam them in and couldn't over fill and made BP plenty hot for most anything.

 

While I'm rambling, after milling your BP, an important step is to granulate it and dry it as fast as possible. On a hot sunny day and in thin layers, it should be crunchy dry in 20-30 min. Stick some in a plastic bag in the sun and make sure no condensation and if so keep drying.

 

Good luck!

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