Can't get lift!

[Xzanth]

I have the 1# end burner tooling from wolter. So you know it's good. Kitty kitty ballmilled for 6 hours and used for the nozzle. I made my own BP withe basic full strength formula 75/15/10 ball milled and screened 2x. I hand RAM a motor and I get no lift at all. I'm a newbie here but I know , basically, what I need to do. Now, I am using a custom built from tubes rocket. It does weight about 2.5 lbs. I'm here looking for all the secrets. Please share with me what might help. I use the 3" tubes with 3/4" ID. I give about 12 smacks per TSP of BP. Alone these things fly. But they can't seem to lift rockets. Should I add some titanium powder or .... Any tips secrets or whatever would help. I want to get some rockets off the ground. My delay and ejection charge are working nice. But no lift. Thanks!!

[FlaMtnBkr]

End burners have much less lift than a core burner and a 2.5 lb rocket is 40 oz and a lot for a 1# end burner. That's a lot for a 1# core burner. I think your expectations are just a bit too high. There are things you can do to increase power if you want but you still aren't going to lift that much weight.

 

Is it just a really big rocket or is it over built with heavy tubes? You might want to either build a smaller rocket or use lighter materials.

 

Edit: You can increase power by making hotter BP and you can also make a small core to give it more initial thrust to get it going. Do they fly well with just a stick attached? Does it take off fairly quick or is it a really slow take off? Does it seem to get to a good height? That is quite a bit shorter tube than normally used which I think is 5.5" but might be remembering that number incorrectly.

 

To increase BP power you can use a hotter charcoal and maybe mill your BP longer depending on your mill and media. Also, making sure it dries quickly is an important step in the process that is frequently overlooked and not discussed and probably the third most critical aspect to making fast BP. There are many threads on how to optimize BP if you do a search. Also, there is no reason to use a binder like dextrin as you don't want hard grains that are hard to compress. Are you wetting the BP powder and granulating thru a screen? I assumed you are but after reading your post again, maybe not? That also seems to slightly boost the power. I don't use any binder and my screen granulated BP is plenty hard for all my needs and are hard to squeeze and break up the larger pieces yet still compresses easily when rammed in a rocket.

 

You can also take a drill bit slightly smaller than the nozzle diameter and drill by slowly twisting with your fingers to make the core about a 1/4" deeper.

 

There are probably some other things I'm not thinking of but that would be a good start.

Edited April 6, 2016 by FlaMtnBkr

[OldMarine]

2.5 lbs? Are you using depleted uranium tubes?

[lloyd]

"I made my own BP withe basic full strength formula 75/15/10 ball milled and screened 2x"

---------------

The key may be what he did NOT say.

 

What sort of charcoal did you use?

What is the nature of your ball mill? What size, what speed, what loads in what ratios between volume of the empty jar and media vs. material?

You SAY you "ball milled" it, then screened it? Why after milling? Why would that be necessary?

 

Properly ball-milled BP should be quite a bit faster and stronger than commercial powder, even when using common air-float charcoal.

 

Common end-burners have way-more lift than that. The only two variations would occur from the nozzle diameter (what size nozzle hole vs. tube diameter) and from weak or strong powder. We known the Wolter tooling has an appropriately-sized spindle, so the only remaining cause must be your powder!

 

 

LLoyd

Edited April 6, 2016 by lloyd

[OldMarine]

I assumed the screening was granulation but I forgot what happens when one assumes!

[lloyd]

It may have been, Patrick. He didn't specify. Specificity am my friend! (in almost all things)

 

Lloyd

[Xzanth]

Thanks for the replies. Hmm. I will get an Estes rocket to try out with my engines. I'm still working on this. I use 5lbs of media to mill one lb BP. And mill for about 6 hours. I screen it with no binder to incorporate the comp more. And it dries nice and fast in the Arizona sun. The tubing I have been using has just been some wrapping paper tubes. And yes even off the stick, it still has a slow lift off to a high range. But I'll see what else I can think of. I'm gonna make a smaller on and just use balsa wood for the fins this time. Either way it's still fun to tinker with all this. Just hoping for some more lift. Or is it the stinger tubes I am using? The look really close to the D size Estes. I'm looking for tubes of that size, and I will add more of a core next time. See if that does anything. My BP is nice and fast. But maybe not. Idk. I don't really have much to compare with, buuut. I did build a c size rocket and compared it to a store bought este, launched both with c-6 and the store one went higher. My rockets are a little on the heavy side. I kinda figured that would be a problem. So, anyone who can direct me to some tubing for the rockets, please. Not just the site, but which one would be the best for just a normal rocket, like if you were to go to the store and pick one up. This is a lot of fun either way. Also my mill is running at about 97rpm. Using the barrels from the harbor freight 6lb set. But I do believe my powder is good. I'll try different charcols as well, any preference on the best wood to use for charcoal? Thanks guys. And gals.

[OldMarine]

A pound of powder is way too much for harbor freight jars. They should only be filled about halfway with lead and then a quarter of the volume with chems. I'm no expert but your rotation speed seems way too fast. The media may be hugging the wall of the jar rather than tumbling.

Lloyd literally wrote the book on ballmilling black powder so I'll defer to his expertise.

[Mumbles]

If you have 1lb of black powder in a single jar from the harbor freight mills, then it sounds like you may be overcharging with your product. Those mills comfortably handle around 150-200g. The rule of thumb is the jar should be about half full of media (which 5 lb of lead should be), and a quarter full of your charge. This will often approximately be the interstices between your media plus a little.

 

Overcharging will reduce milling efficiency. Now, there are a lot of variables at play, but you did say that your motors are not quite up to par with Estes. This could be something simple like a shorter core, or larger nozzle. Then again, it could be a slightly slower propellant. Out of the mill, how does the BP burn? A small pile should burn in an instant. For me the real test is burning on a piece of paper. The BP should barely toast it, and leave little to no residue.

[lloyd]

nah... at "double-filled", he's not milling at all... he's just 'tumbling' the raw ingredients for 6 hours, then taking them back out of the jar in essentially the same condition they went in.

 

Xzanth, determine the volume of your jar. For grins, let's say it's 1/2-gallon.

 

For a 1/2-gallon milling jar, you need 1 quart of milling media, and one pint of ingredients to be ground.

 

Don't go by weight on anything... milling loads are calculated by volume.

 

Your milled powder should come out so fine you cannot feel or see ANY grains. It should burn so fast that, as Mumbles said, it only 'toasts' a piece of paper, but doesn't catch fire to it.

 

Until you do it right, you might as well just grind up your chemicals on a flat rock with a rolling pin, for all the actual milling you're getting done.

 

LLoyd

[stix]

. . . A small pile should burn in an instant. For me the real test is burning on a piece of paper. The BP should barely toast it, and leave little to no residue.

 

That's a great way to put it Mumbles. Xzanth, you still haven't mentioned what charcoal you have used, nor have you told us the size (diameter) of the nozzle.

 

These are important things to know as well, regardless of milling issues.

[Xzanth]

Oops I meant 5lbs to a 100 gram batch. My bad

[Xzanth]

The jar is only 1/3 to 1/4 full with media. I'll test it on paper to see. But on my testing brick its whoosh. But I'll see after that. I also might wanna get a scale that weighs in better increments. And the only charcoal I have is what i burned out of some 2x4 from home depot. So I'm guessing fir or spruce. I know charcoal matters. I'll look more into it. I also have some oak charcoal. And I was reading, 80-100 rpm is good. I managed to get 97. On both my Mills. But I'll test a few things and post some pics and all that today.

[Xzanth]

Don't know the size. It's from wolter 1# end burner tooling, which was sent to me non standard. Machined wrong and the base creates a nozzle an inch into the tube. I used washers to make it work.

[Xzanth]

Here is what it looks like and what I had to do to make it work. They are fixing the problem.

[Xzanth]

I'll measure things out, check my powder, and post more. As far as my mill. I worked on it for a while. It's working g nicely. Now to make sure I'm getting the comp right. That's the important part

[schroedinger]

97 rpm? Thats way to fast. Slow it down to 80 rpm. Your meadia will just cling to the wall.

5lb should fill a 6lb jar half full, what size is your media, 10 mm is a good size for these jars.

 

What do you mean by it makes whoosh? Whatbi experienced as a powerfull feeling powder whith a whoosh is a rather slow powder that has more of a pushing power. You need a powder that just burns on instant.

 

To determine how good you powder is, you should do the baseball test. This way we can compare your powder.

 

How did you cock the charcoal from youre 4x4's? Retort, Tlud or just what was left over in a fire pit?

[Xzanth]

Yeah the BP is a little dirty. Video next

[Xzanth]

[Xzanth]

Whoosh as in burns up instantly. But it's dirty. I just burned the 2x4s and crushed it easily in my hands and screened it through my kitchen strainer. It's not the right charcoal, but it's all I got for now. The shot I used was 1/2 inch lead bullet balls things. Ha-ha. I'm just working with what I got. I know with some good info from the forums and some tinkering and work. I'll get it. But for now, I know my rockets are heavy. So I'll make a smaller one to see what happens.

[Xzanth]

But my media doesn't stick to the sides cause I can hear it tumbling along. Maybe it's not 97, I just put a piece of tape on it, video recorded it for 10 sec and x6. So it's somewhere in the good range. Thanks for all the help Edited April 6, 2016 by Xzanth

[schroedinger]

Well that bp is not fast enough. Make yourself a TLUD and cock up some propper charcoal. The charcoal will be the main problem.

[Xzanth]

Oh and spindle is 3/16 at the top

[Mumbles]

It's not stellar black powder, but you're closer to high quality than not. Your RPM's are fine. The optimal speed (65% of the critical speed) is around 92 rpm. You're a touch fast, but close. The BP burns reasonably quick, but there is a fair amount of residue left behind. This could be remedied with more milling. Alternatively, it could be a high ash content in your charcoal. That's what I think is the more likely suspect.

 

Try looking into retort charcoal cooking, or a TLUD (top lit up draft) cooker. Both will cook charcoal in a basically oxygen free environment, and cut down on the ash. 2x4 usually aren't a bad source of wood actually.

[Xzanth]

Just re-milled it for a little while. And it burns very slow now straight from the barrel to the paper. ....... Idk. I guess I give up for a while

Edited April 6, 2016 by Xzanth