Sugar Rocket Issues

[Differential]

This is what I'm trying to do. It's a long video but you get the idea and you can skip forward to the end to see the launch.

 

Dissolve the sugar and KNO3 in hot water and then boil it down. It takes a little longer, but you will get a much faster, more consistent burn. In the video, you can see that it's a little bit burnt, and that there are still some lumps of KNO3. The final product should be white or off-white, not brown.

[braddsn]

I argue with Oinikis about stuff all the time. It's fun. But I would argue with someone at NASA before I would argue with O about rockets.

[stix]

http://editorial.designtaxi.com/news-lingerie2304/7.jpg

 

Oh, the Humanity!!... that's horrible - Bastard

Edited March 6, 2015 by stix

[dagabu]

BWWAAAAA-HAAAAAHHAAA!

[Jakenbake]

That guy has to be smuggling prunes or something

[dagabu]

Naw man, its STIX actual picture!

 

Sorry STIX but you DID call me a bastard!

 

Just funnin all, I do love this place.

[stix]

Naw man, its STIX actual picture!

 

Sorry STIX but you DID call me a bastard!

 

Just funnin all, I do love this place.

 

No probs Dags. Anyways I decided to take a more 'masculine and manly' approach - this posted image of me wearing pink long johns is for all the ladypyro's out there It does look rather intimidating and aggressive, and I don't normally smoke huge charcoal sticks but who cares. I just hope I don't put all those potential women candidates off. Unfortunately those dating sites don't seem to be working that well for me at the moment, I don't know why. So, why not try something different?

 

ANYWAY... BACK ON TOPIC...

 

 

https://www.youtube.com/watch?v=hyPysthIRss

 

This is what I'm trying to do. It's a long video but you get the idea and you can skip forward to the end to see the launch.

 

That fuel looks pretty lumpy and the ground test about half way through looked like the fuel didn't burn all that well, BUT the result worked well - job done.

 

Sorry about all the distractions regarding pink undergarments - So, where are you at with this now?

 

Cheers.

Edited March 6, 2015 by stix

[gregkdc1]

Back to the original topic

When I was making cored sugar rockets sometimes they would burn great and other times not at all. With sugar the flame will sometimes have a hard time traveling up the core so it burns somewhat like a hybrid between a core burner and end burner with little to no thrust. As soon as I started putting the igniter all of the way into the core this problem went away. On the other hand I started to have a few more cato's and had to back off on the KN just a little. If you are using fuse you may need to use quick-match or maybe some slow bp in the core to get the flame all the way to the end.

[stix]

Back to the original topic

When I was making cored sugar rockets sometimes they would burn great and other times not at all. With sugar the flame will sometimes have a hard time traveling up the core so it burns somewhat like a hybrid between a core burner and end burner with little to no thrust. As soon as I started putting the igniter all of the way into the core this problem went away. On the other hand I started to have a few more cato's and had to back off on the KN just a little. If you are using fuse you may need to use quick-match or maybe some slow bp in the core to get the flame all the way to the end.

 

Yep, agreed. You really do need to ignite as far up the core a possible. I use homemade e-matches and have never had an ignition failure.

 

Cheers.

[dagabu]

Back to the original topic

When I was making cored sugar rockets sometimes they would burn great and other times not at all. With sugar the flame will sometimes have a hard time traveling up the core so it burns somewhat like a hybrid between a core burner and end burner with little to no thrust. As soon as I started putting the igniter all of the way into the core this problem went away. On the other hand I started to have a few more cato's and had to back off on the KN just a little. If you are using fuse you may need to use quick-match or maybe some slow bp in the core to get the flame all the way to the end.

 

Peppering the core with granulated BP helps a lot in core lighting.

[Oinikis]

The fuel making process is very important. I wouldn't advise the technique used on that video, and ground test showed the fuel wasn't very good.

 

I use 2/1 KNO3/Sugar ratio (66.7 KNO3). So, I weight out 2 part KNO3, 1 part sugar, and 1 part water by mass. I put the nitrate and the water in a shallow pan (don't use a high walled pot), and heat while mixing. when it reaches about 80C all the nitrate should be dissolved and only then I add sugar. This is important, because in R-Candy only the sugar is molten, so we need water in order for the nitrate to mix it at molecular level.

 

While it's cooking keep it on low heat and mix it non stop, and make sure you scrape all the fuel from the bottom, so it doesn't burn one one side, while remaining wet on the other. When it's stars acting like clay, take a small piece out, and put it on a cold surface. It will cool quickly, and when cold it should be rock-hard and snap in half like something hard, when you try to break it, if it doesn't, cook it until it does.

 

This way R-Candy will be way more energetic, because it will be better mixed, and the sugar won't be caramelized. It's important, because caramelizarion takes away energy, and make it more hydroscopic. The fuel should be this color or lighter. Also, keep the heat so R-Candy would be clay like, if it's liquid like in the video, it's overheated and caramelizes. Of course, as I mentioned some time earlier, be careful and do this in a non-living area.

Edited March 7, 2015 by Oinikis

[ryandgarrison]

Hey guys, thanks for all the feedback.

 

So I tried again with the same process, and as you guys said, I kept track of the data as I went along making the fuel. However, I had a ton of problems casting it and have taken a step back to attempt dry mix motors inside of PVC piping with a clay nozzle. It's easier and less likely to fail every time.

 

I followed this tutorial:

 

 

This guy also has a tutorial for "solid" fuel or, in other words, the cooked fuel instead of dry mixed. That's also what I was basing my initial attempts off of. But again, I'm switching gears for now.

 

Now what he does in another video is make a simple cardboard and duct tape rocket (which he shows how to build in yet another video). Obviously it's not going to be perfect, but it's CHEAP and really fun to make and as you can see in the video below, it works!

 

 

However, when I gave it a shot, it also failed!

 

Here's my photo

 

http://s15.postimg.org/8j3k7cqzf/rocket.jpg

 

After this moment, it spiraled out of control.

 

So some questions:

 

How do you measure the length of a rocket compared to the size/length/placement of the fins? I imagine that this rocket was unstable because of not ideal measurements and sizes? And therefore the center of gravity and the drag was all wrong? I realized after that my rocket, constructed the same way as his was only half the length. So does that change it as well?

 

 

I know that this is all very rudimentary, especially here where a lot of you guys have years of experience and a duct tape rocket probably sound ridiculous but I'm new, curious, and just experimenting!! Thanks for the help.

[Oinikis]

Keep in mind that most tutorials on youtube are made by people, who aren't really good (Kruger-Dunning effect), and since you are on this forum and have been directed the right way and to the right literature, your knowledge exceeds theirs. So I suggest you reading on websites like these: http://nakka-rocketry.net http://www.jamesyawn.net and experimenting on your own (Safety first!).

What problems you had with casting and what were your techniques?

As for fins there isn't really a rule that I'm aware of. However the websites might answer that.

Edited March 10, 2015 by Oinikis

[ORMDale]

Ryan, there is nothing wrong with dry pressed sugar rockets. They go like hell. When I decided to get into this, my plan was to get set up with a ball mill and start making BP rockets. I had looked into rcandy, but it seemed a lot of damn work to make that hot sticky mess and then try to press it into a mold before it cools. So I said no I will wait until I'm milling my own black powder. Then I saw that now famous video you posted, and I thought to myself that damn, I could have one of these done by tomorrow..

 

So I did, and it was pretty much exactly his recipe, with pvc pipe, but an inch longer. I didn't use stump remover, because 99.8 pure potassium nitrate is dirt cheap online and I already had it, and I blade milled the shit out of it and added some red iron oxide, then blade milled the shit out of some pure baking sugar, because store bought powdered sugar has starch and probably other crap in it. I hot glued a couple 36" Home Depot sticks on launched it. Gone. Out of sight and gone. So I had to do it again, because it was rad as hell. But I kinda felt like an asshole for putting that much pvc pipe that high in the air to fall God knows where, so I made the next one a little longer so I would have room to add some flash on top of the bulkhead to blow the whole thing to pieces before it fell. There was room for 13 grams. I saw it report, but it was too high to hear it. But then, later, I felt like even more of an asshole for spreading shards of pvc over the countryside, but I was hooked.

 

Paper tubes. They are just as easy to work with and much safer. I just can't get behind pvc. If something goes wrong, it'll blow sharp nasties everywhere. Phil's General Store has some very nice 3/4" paper tubes for a great price.

 

If you really wanna go all home made with your rocketry, I would suggest stick rockets to start out with. You'll get joy right away and take what you learned into finned rockets later if you still want to.

 

Sorry for the ramble. Stress day at work and too many beers tonight..

[stix]

I'd forget about the "duct tape rocket" and look into making a "proper" model rocket - if that sort of thing appeals to you.

 

It's a bit of a sharp learning curve but I suggest looking at this:

http://openrocket.sourceforge.net/

 

It's free open-source software and has many features - one is to design your own rocket body with fins etc. and check stability . A brilliant piece of software, at no cost but a reasonable amount of effort is required to use it. Afterall it "IS" Rocket Science

 

Alternatively, to get a "fix" just attach a stick to it as ORMDale suggested. You'll at least know where you stand in regard to your motors performance without complicating it with fins, CG, CP etc. Then later you can investigate further.

 

Cheers.

Edited March 11, 2015 by stix

[chand]

In my sugar rocket it is CCreating more pressure inside core and so much pressure that nozzle blows out so much force what could be improvement that should be done

[chand]

Any one knows how to make altitude meter at home

Any one knows how to make altitude meter at home

[chand]

My propellent is sugar and kno3 I have combustion chamber with diameter meter 3cm and nozzle with 2 to 3 mm it will work or not

[webski]

For sugar rockets using the dry rammed method (as per Grant Thompson video) would adding iron oxide make it faster (better) ?

This seems like an easy and relatively safe method with good results.

I'd stay away from the pvc if I could find some cheap 3/4" tubes.

what do you guys think ?

[stix]

Hi webski, are you asking because you have tried his method and aren't getting good results - or thinking of making it, and just wondering?

 

If you follow his method you may or may not get the same results - but it's probably worth giving it a go. As for adding RIO, I don't believe he found it necessary to use, so why introduce a potential cato situation?. Adding around 1 to 2% RIO will indeed make it burn faster, but "faster = better"?... I don't think so, not with that particular fuel geometry anyway.

 

Having some proper tooling instead of drilling out the core is a more consistent and reliable method imo.

 

You might glean something from this thread - it does tend to go off on a wild tangent at times, but I think there's a lot of good, positive and worthwhile info there.

http://www.amateurpyro.com/forums/topic/10324-substitute-for-fuse/

 

Cheers.

Edited April 10, 2015 by stix

[stix]

 

No it doesn't - you were correct in what you said before.

 

example:

 

15cm length core burner (nozzleless motor):

 

1cm core = 1cm nozzle = kn ratio of 60

as it burns out :

1.5cm core = 1.5cm nozzle = kn ratio of 40

2.0cm core = 2.0cm nozzle = kn ratio of 30

2.5cm core = 2.5cm nozzle = kn ratio of 24

 

The ratios above would be even more regressive as the fuel length is reduced - I have not taken that into account. The thrust to weight ratio over time should be taken into account, but for the purposes of this exercise it shouldn't have too much bearing on the result.

 

example 2 (fixed nozzle = 1cm):

 

15cm length core burner:

 

1cm core = 1cm nozzle = kn ratio of 60

as it burns out :

1.5cm core = 1cm nozzle = kn ratio of 90

2.0cm core = 1cm nozzle = kn ratio of 120

2.5cm core = 1cm nozzle = kn ratio of 150

 

The ratios above are "progressive" - as it will always be with a fixed nozzle and a core burner, unless you have a star shaped core or some other geometry.

 

I'm very confident in the math above - but someone else should verify. I believe it is correct, otherwise I'll go gay. Not that there's anything wrong with that!, but i'd prefer not to. Especially since I know a lot of nice beautiful women at the moment and it would be such a waste.

 

Cheers.

 

 

 

Nah!.. I disagree... What a crock!! - perhaps you guys (oinikis and dag's) can jump around the tabletop with glee, swinging gayfully arm in arm, wearing your frilly pink and rainbow coloured underwear whilst drinking pimms and pink champagne ... ok... all fine, there's nothing wrong with that, but there is no way I'm going to agree with what has been put forward above.

 

I guess I'll have to prove otherwise, which will sidetrack me from what I'm doing now, but nevertheless needs proving.

 

Luv you guys Cheers.

 

Well, I did say that I would come back to this and try and prove otherwise - or prove something at least, through actual scientific process and measurement.

 

I'm part way through testing and what I've seen already shows that a nozzle-less rocket motor IS INDEED regressive - given that the geometry of the core, the fuel weight and type are the same. The actual specific impulse in the graph is irrelevant at this point. I will post comparisons and actual data later.

 

I'll be doing some more tests to ensure that the results are correct, but I believe that what I originally posted was "theoretically sound" even though it seemed based upon a speculative "hunch".

 

The load cell used for the tests has a resolution of 1 gram and was set to 100 samples per second. I have only posted the "nozzle-less" graph. I will be posting all the final results in the next month or so.

 

btw. The load cell used was made by a close friend of mine - very accurate and reasonably cheap to make. He's told me that he's happy to provide details and instructions for making one. Gratis of course

 

Cheers.

[webski]

I've read all the comments and checked out most of the leads and tangents, and continued to test sugar rockets.

My conclusions have led me back to dry mix 65/35 powdered propellant rammed into 3/4 tubes.

I tried melting and casting fuel (too messy and time consuming)

melting and recrystalizing, grinding and ramming ( very powerful, but inconsistant)

finally back to dry mix. (easy, efficient and consistant)

 

My questions are :

 

what would be the ideal nozzle size for a 3/4 x 5" tube and what size spindle should I use ? (length/diameter)

and,if I use a 5/8 tube x 4" what should I try as a starting point.

 

also related:

What would I do to make this a lower impulse smoke bomb ?

 

I know that it seems that I'm taking the easy way out, but I've spent alot of time and effort trying to get it right, and

I want to have some success that I can consistantly duplicate.

 

My trial and error methods are sometimes frustrating and I do want to be safe and successful in the near future !

 

thanks for your insight and help,

 

WEBS

[mikeee]

Webski,

 

You should try making some whistle fuel some time, the process is pretty simple and there are some tutorials

on the process used in making it safely. You need to press the fuel grain instead of ramming it tough. But the fuel

can be easily adjusted for power by mixing it with charcoal. The fuel can also be used loose for reports and burst charge.

Very versatile fuel and you can add fine metals to the delay for nice rocket tails.

 

http://www.firesmithtools.com/Tutorials/whistlefuel.pdf

[webski]

I have made some whistle mix and have used it for headers and rockets, and it works great, through I'm really trying to dial in my dry mix sugar comp.

and would really like some info on spindle size and nozzles so get close to right without all the trial and error.

I'm making 5/8 and 3/4 rockets.

 

thanks for your help

[mikeee]

Webski,

 

What kind of pressure are you putting on the dry fuel grains?

Every person makes fuel a little different which determines the power and performance of the fuel.

If you are doing a dry sugar mix are you milling the chemicals prior to mixing?

There are several websites that focus on Sugar Fuel Rockets and there are plenty of variables with the fuels & motors. Someone posted a link several days ago to a website that shows spindle profiles based on rocket types, you type in the motor type and size and the optimal spindle design is shown. I might have it in my bookmarks, I will look for it and forward if I find it.

Edited June 19, 2015 by mikeee