Alternative rocket casings

[hillbillyreefer]

[/First off thanks to all who post in the rocket section, your knowledge has been invaluable to me.

This morning while cleaning in my man cave I came across a bunch of 12 gauge shotshell hulls. Figured they may work for rocket casings. Popped the primers out of 2. The first a 2 3/4 federal topgun. I filled it to the crimp with pressed BP, and plugged it with bentonite. Put a stick on it and lit 'er up. To my surprise it flew! First attempt, pretty good for a neophyte. Anyway it went up about 30 feet, angled over flew another 40 yards and spudded. It started to sound odd about 1/2 seconds or so in. Turns out the whole body melted to nothing, pretty much what I expected.

Second attempt 3" Winchester of some sort. Smaller primer hole. Wrapped it with about 10 wraps of gummed tape. Packed it in the same method as the first one, and put a core about 3/8" into it with a drill bit. Attached to a stick and fused it, and touched it off!! We'll holy sheep turds, she leaps into the air and streaks into the heavens just like my factory bought Estes. Estimate altitude of about 250-300 feet, the she nosed over and ended up about 200 yards down my driveway. WooooHooooo!

A couple more to play with tomorrow and then attempt to lift something. Maybe try a couple sugar rockets too. Pretty happy with the results considering all I expected was a Cato.

]

Edited March 23, 2011 by hillbillyreefer

[NightHawkInLight]

Wow, I like the idea a lot! I particularly like that a shell casing comes with a centered hole built into it with the primer popped out. Dirt cheap too. I think cored rockets would be much more ideal than end burning because the lower portion of the wall would not be exposed to heat until the fuel was almost entirely expended. That is, if the casings can withstand the pressure. I'm going to have to try it out for myself.

 

To me this seems like the rocket version of a film canister shell. Perhaps it could be the dirt cheap and easy option for beginners to rocketry that film canister shells are for shell building. Really good thinking!

[hillbillyreefer]

Wow, I like the idea a lot! I particularly like that a shell casing comes with a centered hole built into it with the primer popped out. Dirt cheap too. I think cored rockets would be much more ideal than end burning because the lower portion of the wall would not be exposed to heat until the fuel was almost entirely expended. That is, if the casings can withstand the pressure. I'm going to have to try it out for myself.

 

To me this seems like the rocket version of a film canister shell. Perhaps it could be the dirt cheap and easy option for beginners to rocketry that film canister shells are for shell building. Really good thinking!

 

I will try a couple different methods tomorrow. A cored with no tape would be handy to have work. Not a big deal though, a bit of tape and about 30 seconds work is all the tape takes.

 

I will look around tonight and see what other brands and makes of hulls I have. I think I've got a couple thousand paper hulls down in the shop, will have to look. They are all a bit different around the primer pockets,

 

I'm curious to try another end burner with some tape this time. If that works I can't imagine an easier rocket to put together.

 

I was watching your Rcandy video last night. Could it just be poured into the hull and then cored after it cools? I need to read a bunch more before I get carried away with this new diversion.

[Blackthumb]

Did that as a kid....try the .410 3" shells/hulls in paper if you can still find them...quick to assemble and perform well!

[Guest no6]

Sweet.

[SirBang]

That sure is an odd idea.

 

I like it:) That must be tested.

 

 

 

Do you have any video of the launch ..

[donperry]

Yup, i've seen the shotgun shell rockets on youtube before

[Blackthumb]

Video cameras were in the thought stage when I fired my first .410 ga rockets...all that remained of their existance was a black spot on the driveway and a smile on my face!

I do remember a 30-06 shell casing w/Zn and S...a jetex fuse thru the primer hole and pressed into the soil....large hole, no rocket to be found...first and last but oh what fun!!

[Algenco]

Video cameras were in the thought stage when I fired my first .410 ga rockets...all that remained of their existance was a black spot on the driveway and a smile on my face!

I do remember a 30-06 shell casing w/Zn and S...a jetex fuse thru the primer hole and pressed into the soil....large hole, no rocket to be found...first and last but oh what fun!!

 

 

Jetex? your telling your age

[hillbillyreefer]

Yup, i've seen the shotgun shell rockets on youtube before

 

d'oh I thought it was something new. Oh well.

 

I found the video camera cables, will attempt to get video today. Then it will take a week or two to figure out how to post it. I think blackthumb and I are around the same age, lol.

 

This mornings projects are: mill some more bp, make up a bunch of sticks, find and measure up a variety of casings, make up some motors, time permitting I'd like to make a batch of sugar fuel also. Oh, and look after the kids, nothing better than the wife leaving us unsupervised.

 

A good starting mix for sugar would be 67:23 KNO3:Sugar correct or is it 63:27? Damn dyslexia! I will look it up before I mix anything.

Edited March 23, 2011 by hillbillyreefer

[moondogman]

d'oh I thought it was something new. Oh well.

 

I found the video camera cables, will attempt to get video today. Then it will take a week or two to figure out how to post it. I think blackthumb and I are around the same age, lol.

 

This mornings projects are: mill some more bp, make up a bunch of sticks, find and measure up a variety of casings, make up some motors, time permitting I'd like to make a batch of sugar fuel also. Oh, and look after the kids, nothing better than the wife leaving us unsupervised.

 

A good starting mix for sugar would be 67:23 KNO3:Sugar correct or is it 63:27? Damn dyslexia! I will look it up before I mix anything.

 

Ive been using 65:35 = 1% red iron oxide.

 

Steve

[dagabu]

Jetex? your telling your age

 

Jetex? What the heck is Jetex? I suppose you old farts will go telling me that it was some kind of fuse or something with a "wire" that ran its length or something silly like that .

[Mumbles]

The only qualm I'd have about recommending these to beginners is the metal "nozzle". I don't know if it'd be wise testing unproven fuels in them at least.

[NightHawkInLight]

The only qualm I'd have about recommending these to beginners is the metal "nozzle". I don't know if it'd be wise testing unproven fuels in them at least.

Yeah but it's light and thin. Certainly not lethal as a projectile. Painful maybe, but less so than a hot glue or solid clay plug. After testing them myself I don't think I'll have any fear in recommending them.

[hillbillyreefer]

The only qualm I'd have about recommending these to beginners is the metal "nozzle". I don't know if it'd be wise testing unproven fuels in them at least.

 

The metal on a cheap low brass winchester is 1.8g and just under 0.008 in thickness. All brands will be about the same. The high brass 3 and 3.5" may have another 0.5 grams of metal, I didn't test any of those. I'll leave the safety debate up to those with more knowledge than me. Will follow along closely though.

 

Thanks for the formula moondogman.

Edited March 23, 2011 by hillbillyreefer

[donperry]

Trust me, that red iron oxide makes the thing goes [voom] if you powder it out after recrystalizing (sorta like granulating)

 

I'll try to do a video of me lighting RIO rcandy powder

[hillbillyreefer]

We just flew three more of the rockets:

All were 3 inch cheap winchester hulls filled to the crimp line with composition, and finished up with bentonite plugs. Weights with 4' sticks were all between 50.5g and 52.0g.

 

1. Rocket was cored about 3/8 into fuel with 11/64 drill bit, was not wrapped with tape to prevent meltdown. When lit liftoff was instantaneous, gone into the clouds.

 

2. Rocket was not cored, but was wrapped with tape to prevent case burn out. When lit it sounded weak and made no attempt to lift off. It did manage to burn it's stick off, the case survived the ordeal. This will probably be my last attempt at non-cored rockets in this configuration.

 

3. Rocket was cored about 3/8" into fuel with an 11/64 drill bit. The case was wrapped with tape to prevent case meltdown. Lift off was instantaneous, gone into the clouds.

 

1&3 were very similar in design and performance. I estimate the cloud ceiling to be 400-500 feet at the time of the test. Socked in badly, had just quit snowing. In hindsight I'm not sure if they entered the clouds or were lost against them at burnout. My sticks may have been longer than needed, they flew in pretty much a straight line.

 

Not sure what else to tell you except they had right around 19g BP in each motor.

 

Now to make them lift something! What would you suggest as a starting point for payload? My thoughts are about 20g.

 

My video skills suck, all I managed was a bit of the lift off of the first one, then nothing but sounds for the next two. If someone really wants to see it, I may be able to get it off the tape and post it.

[NightHawkInLight]

If you try to film the next ones it will make it easier if you're further away when they take off. Also try to center them towards the bottom of the frame while the fuse is burning. There's no need to see much of the ground under the rocket.

[Peret]

Jetex? What the heck is Jetex? I suppose you old farts will go telling me that it was some kind of fuse or something with a "wire" that ran its length or something silly like that .

Jetex was a model jet engine - for model aircraft, not rockets - when I was a kid. The motor was a little aluminum can about an inch long with a clip-on end cap that had a pinhole in it. The fuel was pellets like 1/2 inch pumped stars, dark green, with guanidine nitrate as the main ingredient. It didn't flame, it decomposed into smoke and ash that stank of ammonia. Jetex fuse was like a super skinny Visco that would go through the pinhole and was used to set the motor off. It was useful for a lot of other things besides lighting Jetex motors.

[dagabu]

Yes, and it had a thin copper wire in the middle.

[Blackthumb]

Hillbilly ...think your last one just cleared my house!!

Got my first Blackthumb with Jetex fuse......

[donperry]

Book 75 Chapter 15 Verse 10 -

Maaaddddd

 

[hillbillyreefer]

Book 75 Chapter 15 Verse 10 -

Maaaddddd

 

 

Can't believe how many times I looked at that and didn't figure it out, and I made BP yesterday. D'oh!

 

On to the matter at hand..

 

Flew 6 rockets last night. 5 with payloads 1 without. The one without flew as expected, disappeared into the cloud, our weather sucks. The other ones that were under 75g total weight flew well. The ones over 75g flew but poorly. Even the 91g easter egg container flew, but it hit the ground after going up about 75 feet and 150 feet horizontal. Just wondering if changing the cores would up the power and get the effect up in the air. Currently they are about 3/8" deep and made with an 11/64" bit. What I'm thinking is a couple sizes smaller bit but run it into the fuel pellet around an inch deep. From what I've read it should create a quicker burn (more power), but a quicker impulse, which is exactly what I'm looking for. The core rule of thumb is 7/10 right? Don't want to get that aggressive right off the bat.

 

A question about sticks, long and light is better than short and heavy right? Picked up some supplies to make a launcher today. Should work better with 1/2" tube launchers than sticking them in the snow. Plus the snow should be about ready to piss off. I hate winter.

Edited March 26, 2011 by hillbillyreefer

[dagabu]

Can't believe how many times I looked at that and didn't figure it out, and I made BP yesterday. D'oh!

 

On to the matter at hand..

 

Flew 6 rockets last night. 5 with payloads 1 without. The one without flew as expected, disappeared into the cloud, our weather sucks. The other ones that were under 75g total weight flew well. The ones over 75g flew but poorly. Even the 91g easter egg container flew, but it hit the ground after going up about 75 feet and 150 feet horizontal. Just wondering if changing the cores would up the power and get the effect up in the air. Currently they are about 3/8" deep and made with an 11/64" bit. What I'm thinking is a couple sizes smaller bit but run it into the fuel pellet around an inch deep. From what I've read it should create a quicker burn (more power), but a quicker impulse, which is exactly what I'm looking for. The core rule of thumb is 7/10 right? Don't want to get that aggressive right off the bat.

 

A question about sticks, long and light is better than short and heavy right? Picked up some supplies to make a launcher today. Should work better with 1/2" tube launchers than sticking them in the snow. Plus the snow should be about ready to piss off. I hate winter.

 

You pose some of the most elementary but most important questions about tuning rocket motors and while these topics have been covered ad nauseum, I like them so much that I will give it a shot. (Dude, this is going to be a lot harder then I thought it would be, the codeine is messing with my mind something fierce)

 

(Core Drilling: I only drill one rocket motor, that is the 1/2" x 3" end burners I use for Monocopters, I drill less then 1/8" in to the powder, I use a drill press and run it at the lowest speed (250 RPM). You would be better served to make some tooling with spindles, start a little long and cut off extra length as you CATO rockets. I dont like or recommend core drilling, the dangers are too great.)

 

Longer cores do allow for a faster dump of thrust and thus, your *Specific impulse ( is a way to describe the efficiency of rocket and jet engines. It represents the impulse (change in momentum) per unit amount of propellant used.^[1] The unit amount may be given either per unit mass (such as kilograms), or per unit Earth-weight (such as kiloponds, since g is used for the latter definition).^[2] The higher the specific impulse, the less propellant is needed to gain a given amount of momentum.) will increase as the spindle or core gets longer and more surface is exposed. Your rockets exhibit the classic signs of the short-spindle phenomenon as the cored portion gets them off the pad and then they essentially become end burners and tip over and fly horizontally for a while. While you will be having some of these pop on you as the core gets longer, testing is definitely worth the time it takes. Take good notes

 

Guidance sticks are one of the hot topics that really bring out the passions in some. I have been super hard core on the "rules" for stick length keeping the minimum stick length 6:1 to motor length, (6" long motor gets a 36" stick and the stick thickness one nozzle ID or 1/4" whichever is greater) until last week when my son and I launched a slow and lazy 1/2" motor with a drinking straw for a guidance stick. VIDEO

 

With only 9" of straw exposed after the end of the straw, the 3" long motor only had a 3:1 ratio and the balance point was almost 1/2 the way up the motor so that according to the recommendations that nearly everyone seems to give, this rocket should not have flown straight, but it did.

 

My recommendation? Start with thin and light sticks and add length and width if the rocket seems to spiral or get squirrely on you.

http://www.youtube.com/watch?v=lWVoTYfKruo

*Wikkipedia

[hillbillyreefer]

You pose some of the most elementary but most important questions about tuning rocket motors and while these topics have been covered ad nauseum, I like them so much that I will give it a shot. (Dude, this is going to be a lot harder then I thought it would be, the codeine is messing with my mind something fierce)

 

I always take the advice of people on medication seriously!! Really, thanks for the reply.

 

(Core Drilling: I only drill one rocket motor, that is the 1/2" x 3" end burners I use for Monocopters, I drill less then 1/8" in to the powder, I use a drill press and run it at the lowest speed (250 RPM). You would be better served to make some tooling with spindles, start a little long and cut off extra length as you CATO rockets. I dont like or recommend core drilling, the dangers are too great.)

 

I understand the issues with drilling the cores. I have improvised a blast shield around my small drill press, everything but my hand is protected, and a short piece of pipe will fix that problem. These motors are 3/4" x 3 so similar to yours. If I had put my mind to it a set of tools could have been crudely fashioned in the time the shielding took. I just had an epiphany while typing this, quick and dirty tooling coming up after work tonight. I have access to several machinists and lathes, so getting a set of proper tooling built is not difficult, in fact it's kind of stupid I haven't got a set yet. One buddy goes on days off Thursday, maybe this weekend, after I hillbilly a set of homemade ones up to experiment with.

 

Longer cores do allow for a faster dump of thrust and thus, your *Specific impulse ( is a way to describe the efficiency of rocket and jet engines. It represents the impulse (change in momentum) per unit amount of propellant used.^[1] The unit amount may be given either per unit mass (such as kilograms), or per unit Earth-weight (such as kiloponds, since g is used for the latter definition).^[2] The higher the specific impulse, the less propellant is needed to gain a given amount of momentum.) will increase as the spindle or core gets longer and more surface is exposed. Your rockets exhibit the classic signs of the short-spindle phenomenon as the cored portion gets them off the pad and then they essentially become end burners and tip over and fly horizontally for a while. While you will be having some of these pop on you as the core gets longer, testing is definitely worth the time it takes. Take good notes

 

Thanks for the definition tutorial, always good to learn something. I'm actually disappointed I haven't had a cato yet. Some of the best videos are Cato's. That being said, there is a certain pride in not having one too, it also means your not trying hard enough.

 

Guidance sticks are one of the hot topics that really bring out the passions in some. I have been super hard core on the "rules" for stick length keeping the minimum stick length 6:1 to motor length, (6" long motor gets a 36" stick and the stick thickness one nozzle ID or 1/4" whichever is greater) until last week when my son and I launched a slow and lazy 1/2" motor with a drinking straw for a guidance stick. VIDEO

 

Mine have been in the range of 15:1 no big deal, just added weight. Now that we are both on the same line of thought on the nosing over thing, shortening the sticks up shouldn't be a problem. Will leave then as they are for now, one change at a time. During the ascent under power, they have been flying true as an arrow(the ones with no payload) the motors with payload have been reasonably stable, until they nose over. But that is more a thrust problem than a stabilization problem, I think.

 

With only 9" of straw exposed after the end of the straw, the 3" long motor only had a 3:1 ratio and the balance point was almost 1/2 the way up the motor so that according to the recommendations that nearly everyone seems to give, this rocket should not have flown straight, but it did.

 

My recommendation? Start with thin and light sticks and add length and width if the rocket seems to spiral or get squirrely on you.

http://www.youtube.com/watch?v=lWVoTYfKruo

*Wikkipedia

 

Thank you for your help Dagabu. It's much appreciated.