How many things are wrong with this test firing? ;)

MrJohnson

Member
Joined
Aug 1, 2010
Messages
7
Reaction score
0
This video of a backyard rocket candy test firing gone wrong is short but pretty funny as the flaming grain shoots out the nozzle and back at the camera. :y:

[YOUTUBE]<object width="480" height="385"><param name="movie" value="https://www.youtube.com/v/SdIOrFVt0Jo&amp;hl=en_US&amp;fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="https://www.youtube.com/v/SdIOrFVt0Jo&amp;hl=en_US&amp;fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>[/YOUTUBE]
 

Rocketman248

Well-Known Member
Joined
Jan 30, 2009
Messages
2,395
Reaction score
14
I'm gonna recommend that you move the "test stand" off the porch. That's just begging for a fire.
 

MrJohnson

Member
Joined
Aug 1, 2010
Messages
7
Reaction score
0
Use something a little heavier to anchor the motor to the ground.

Just for the record: That's not the motor taking off. That's a wad of hot propellant shooting out the nozzle.

Here's a photo of the "engine" (brass plumbing fittings with an 1/8" nozzle of 4 #6 steel washers) and the little 4-gram, end-burning grain that was fired in the video. (The next grain was wrapped in masking tape and performed beautifully.) The engine was clamped on to the chair. (Another, identical brass end cap seals it.)

Propellant formula deleted I think this stuff would work OK just end-burning with no core.

2wm4dgh.jpg
 
Last edited by a moderator:

MrJohnson

Member
Joined
Aug 1, 2010
Messages
7
Reaction score
0
I'm gonna recommend that you move the "test stand" off the porch. That's just begging for a fire.

Setting the house on fire would be bad, but having that little comet come up and hit me in the face would be worse. You can't hear it in the video, but when it hit the rail, it sounded like a .22 going off. Scary.

Good thing the wife wasn't home. ;)
 

rcktnut

Well-Known Member
Joined
Oct 26, 2009
Messages
1,897
Reaction score
487
Location
Sheboygan WI
Setting the house on fire would be bad, but having that little comet come up and hit me in the face would be worse. You can't hear it in the video, but when it hit the rail, it sounded like a .22 going off. Scary.

Good thing the wife wasn't home. ;)



Setting someone elses house on fire or hitting a bystander in the face would be scarier yet. After veiwing some of your other "experiments" I'm glad I don't live nextdoor!!!
 

troj

Wielder Of the Skillet Of Harsh Discipline, Potent
Joined
Jan 19, 2009
Messages
14,632
Reaction score
591
This kind of activity doesn't belong A) in a residential neighborhood, and B) anywhere near the house.

-Kevin
 

RobD

Well-Known Member
Joined
Jun 6, 2010
Messages
136
Reaction score
3
I like experimenting with sugar motors.

My concern is that you are using a complete metal case. Potential pipe bomb if your pressure gets too high (especially if something like loose propellant or cardboard plugs the nozzle)

We have re-used bp motors, pvc, and even some spent AT single use. 'Plug' type cement works well for nozzles and somtimes for capping the case. It sets in about 5 minutes.

I believe that we have the propellant consistent enough to try loading in a commercial reloadable case. I have too many other projects going right now to spend money on that though.

It is pretty cool to watch a sugar motor go.

I don't know what the forum's stance is on experimental propellant. pm me if there is an issue with discussing this here.

Thanks.

Rob
 

MrJohnson

Member
Joined
Aug 1, 2010
Messages
7
Reaction score
0
I like experimenting with sugar motors.

My concern is that you are using a complete metal case. Potential pipe bomb if your pressure gets too high (especially if something like loose propellant or cardboard plugs the nozzle)

We have re-used bp motors, pvc, and even some spent AT single use. 'Plug' type cement works well for nozzles and somtimes for capping the case. It sets in about 5 minutes.

I believe that we have the propellant consistent enough to try loading in a commercial reloadable case. I have too many other projects going right now to spend money on that though.

It is pretty cool to watch a sugar motor go.

I don't know what the forum's stance is on experimental propellant. pm me if there is an issue with discussing this here.

Thanks.

Rob

Thanks, that's all useful feedback. It's a tiny "motor with a big nozzle but point taken. It's just for static testing. I wanted something repeatable for testing with and without iron oxide. (Adding 1% iron oxide did make a huge difference--cut burn time almost in half.) But I was amazed at how the tiny motor--you'd think it was pretty harmless--spit out a nasty burning mass, so I thought I'd share in case some other knucklehead might benefit from it (or saner people be entertained by it).

I'm new to propellants (as you might guess) but I have to assume that it's OK to discuss them in a propellant topic. Otherwise it seems like it would be like modern-day ham radio operators who buy all their gear and don't much know or care how it works. But that's off-topic editorializing, and I do get the message: Don't do testing where you can hurt people and where you might start a fire. Got it. :blush:
 
Last edited:

troj

Wielder Of the Skillet Of Harsh Discipline, Potent
Joined
Jan 19, 2009
Messages
14,632
Reaction score
591
I don't know what the forum's stance is on experimental propellant. pm me if there is an issue with discussing this here.

The biggest rule is No Formulas.

-Kevin
 

WillMarchant

Well-Known Member
TRF Supporter
Joined
Jan 14, 2009
Messages
2,594
Reaction score
245
I'm new to propellants (as you might guess) but I have to assume that it's OK to discuss them in a propellant topic. Otherwise it seems like it would be like modern-day ham radio operators who buy all their gear and don't much know or care how it works. But that's off-topic editorializing, and I do get the message: Don't do testing where you can hurt people and where you might start a fire. Got it. :blush:

The subject area is "propulsion" not "propellants" so it covers a lot more than mixing research motors.

I'm guessing you are not a ham radio operator if you think the hobby consists solely of "appliance operators."
 

blackjack2564

Crazy Jim's Gone Banana's
Joined
Jan 17, 2009
Messages
9,167
Reaction score
1,385
Location
Savannah Ga
If you really want to follow the road to serious sugar propellant, check out this website. I have been following it for many years.

They are doing a sugar motor to space shot, link is on front page.

https://www.nakka-rocketry.net/

I bought the CD so I could read off line. This site will keep you busy for months. The amount of research and formulas is staggering. Helps keep one from making the same mistakes, saves time and will get you on the road to success quickly.

Good luck and enjoy!
 

troj

Wielder Of the Skillet Of Harsh Discipline, Potent
Joined
Jan 19, 2009
Messages
14,632
Reaction score
591
If you really want to follow the road to serious sugar propellant, check out this website. I have been following it for many years.

Thanks for posting that, Jim -- I hadn't had a chance to go dig up the link.

Everyone I know who's interested in sugar propellant says the same thing -- that's the site to go to.

-Kevin
 

niels popping

Well-Known Member
Joined
Aug 2, 2010
Messages
278
Reaction score
0
I like experimenting with sugar motors.

My concern is that you are using a complete metal case. Potential pipe bomb if your pressure gets too high (especially if something like loose propellant or cardboard poreanym build lugs the nozzle)

We have re-used bp motors, pvc, and even some spent AT single use. 'Plug' type cement works well for nozzles and somtimes for capping the case. It sets in about 5 minutes.

I believe that we have the propellant consistent enough to try loading in a commercial reloadable case. I have too many other projects going right now to spend money on that though.

It is pretty cool to watch a sugar motor go.

I don't know what the forum's stance is on experimental propellant. pm me if there is an issue with discussing this here.

Thanks.

Rob



A long time ago I made a PVC motor, 54mm
with aluminum layer around it (0,8mm)
and glue it together.

OK I know it wasn't that strong.

the first test seen on this picture, the test platform start to burn to the ground.
the engine was leaking fuel, and shoots the casing in the air.

but the casing survived and I made it a little bit stronger.
using a kno3/sugar grain with a single core from the front to the end straight, the grain was 700mm long

I did a next test that one was in the first seconds really loud en working fine with high thrust. but after 3 second it explode, raining pieces of PVC and aluminum, and the neighbors thought the was a crashing Jet-fighter.



at this time, when I made a new engine I'm using a strong metal pipe


Rocket%20enige%20test%200001.jpg

Sequence%2006.jpg
 

niels popping

Well-Known Member
Joined
Aug 2, 2010
Messages
278
Reaction score
0

Than could people like bin laden,
find this forum on Google and See's how to make propellant and use it as an explosive or some thing.

just like talking about a nuclear bomb, plutonium & high explosive,
yeah but how much. and how made you one.
 

ghrocketman

Well-Known Member
Joined
Mar 29, 2010
Messages
458
Reaction score
1
Ahhh....this was NO BIG DEAL.
Nobody got hurt, nothing caught on fire, and there was no window shattering explosion.
Could this have been performed MORE safely in a better manner ? ABSOLUTELY.
In my book, no harm = no foul for everything ALWAYS no matter where it is at.
 

RobD

Well-Known Member
Joined
Jun 6, 2010
Messages
136
Reaction score
3
Yeah, such a small amount of propellant is pretty harmless as far as explosions go. I am assuming Niels is either joking about using a strong metal pipe, or he is very educated on propellants and internal pressures, etc.

I thought I saw something about discussing propellants in the rules somewhere...

The website operators don't want to be the reference given to the fire investigator about where the big idea came from ;)
 

niels popping

Well-Known Member
Joined
Aug 2, 2010
Messages
278
Reaction score
0
I have found some useful information about making HPR rocket engines for you
https://www.thefintels.com/aer/rocketmotors.htm

but be careful if you make a hpr rocket engine,
you need to know first how powerful you propellant are.
with kno3 sugar you can better try first some grain with a surface burning, ( no core).
and see if you cassing likes the pressure.

I´m using a more powerful nitrate than kno3.
with a conical core for each grain separate with a centering from
metal.

that way you can better control the inside pressure.

also your nozzle needs to be right, if the hole is to small its like a JDAM (bomb)

if you test a new engine, be aware for windows,
and have a huge amount of water with you, for if it goes wrong.

use a electronic ignition, that could be a small rocket engine, mostly I´m using a C6 engine for ignition of the grain.
or using a piece of more powerfull proppelant to ignited.


by hybrid engines it goes a lat different,
I have not the education at this moment to do that save.
 

Rutrag

Active Member
Joined
Jul 10, 2010
Messages
38
Reaction score
0
Ahhh....this was NO BIG DEAL.
Nobody got hurt, nothing caught on fire, and there was no window shattering explosion.
Could this have been performed MORE safely in a better manner ? ABSOLUTELY.
In my book, no harm = no foul for everything ALWAYS no matter where it is at.

Everytime you do something dangerously, you're playing Russian roulette. I would rewrite your equation to no harm = you got lucky. Take it as a learning experience and do it more safely next time. Unfortunately many people assume that luck = safety, and that ain't so. I have completed many accident investigations where the injured individual's first comment was "I never thought that would happen. I've been doing it that way for 20 years."

Here's a link to a video I show my employees to illustrate the point. (It's about 10 minutes.)

https://www.harsco.com/onsite-value/safety-and-environment.aspx

Click at the end of the third paragraph where it says "Click here to watch the video." (Incidentally, this is not my company.)

Not trying to be a spoilsport, but I hate to see guys get hurt or cause property damage if some simple precautions can prevent it.;)
 

rcktnut

Well-Known Member
Joined
Oct 26, 2009
Messages
1,897
Reaction score
487
Location
Sheboygan WI
Just for the record: That's not the motor taking off. That's a wad of hot propellant shooting out the nozzle.

Here's a photo of the "engine" (brass plumbing fittings with an 1/8" nozzle of 4 #6 steel washers) and the little 4-gram, end-burning grain that was fired in the video. (The next grain was wrapped in masking tape and performed beautifully.) The engine was clamped on to the chair. (Another, identical brass end cap seals it.)

Propellant formula deleted I think this stuff would work OK just end-burning with no core.

2wm4dgh.jpg





I have no problem what-so-ever with people wishing to make their own motors/propellant as long as it is done properly. What I see in this picture is what could be construed as a PB, or nowdays IED by the authorities. I, me, myself, believe you 100%, that your intentions to make a rocket motor are genuine.

To make a properly functioning rocket motor involves a great deal of science/math. Simply forming a rough propellant grain and putting it in a metal pipe with an 1/8" hole is not what I would consider an honest attempt at making a true rocket motor.

Why am I so concerned about what I see?? Well first of all you are the one that asked what is wrong with the test firing. I've also "experimented" with sugar motors as well as zinc/sulfer, BP in the early 70's. There were a few of us guys that were involved with this for qiute a few years. We used very little science in the production of our motors. Trial and error was about it.

None of us had the "guts" to use metal casings (pipes). We used heavy walled cardboard tubes with plaster/water putty nozzles. What we were trying to do was to make large "Estes" type motors. We had more failures than success. All of our testing, flights, etc. were done on my Grandpa's farm well away from buildings and people. We were guilty of mixing up "stuff" at home (backyards) and lighting small samples.

For all the "experimenting" we did back then we were very fortunate in that only one of us was seriously injured. He was packing a BP motor that "went off", taking 2 fingers and half of his thumb with it. He also suffered a groin injurey on which I will not elaborate. Needless to say that incident ended our motor production.

Accident or not, we were coming to the conclusion anyway that we could not make consistant, reliable, safe motors. Now,commercial motors only for me, thank you, and things can "go wrong" with them also. That's why we have the safety codes.

Things have changed a heck of a lot since then. We were able to buy our supplies at the corner pharmacy. Implications of getting caught with the "stuff" back then were minor. I would never want to be caught with the item you have in your picture nowdays. You will be a terrorist and be treated as such until you prove otherwise.

Also now, for those that wish to "roll their own" there is a wealth of info out there, computer programs, experienced persons etc. to help in making/testing motors in the safest possible way.

Best wishes on your motor making, Be Legal, Be Safe!!!
 

ghrocketman

Well-Known Member
Joined
Mar 29, 2010
Messages
458
Reaction score
1
Treating NATURAL BORN US Citizens as terrorists for experimenting in making rocket motors is gubmint abuse of power at its WORST.
Total load of nonsense on numerous fronts, the largest of which is violation of presumption of innocence (instead of guilt), which I think even requiring posting of bail/any sort of bond for any charge violates as well.
 

Mikus

Well-Known Member
Joined
Jan 27, 2009
Messages
651
Reaction score
7
In my line of business, we would have termed it a "near miss". :y:

Everytime you do something dangerously, you're playing Russian roulette. I would rewrite your equation to no harm = you got lucky. Take it as a learning experience and do it more safely next time. Unfortunately many people assume that luck = safety, and that ain't so. I have completed many accident investigations where the injured individual's first comment was "I never thought that would happen. I've been doing it that way for 20 years."

Here's a link to a video I show my employees to illustrate the point. (It's about 10 minutes.)

https://www.harsco.com/onsite-value/safety-and-environment.aspx

Click at the end of the third paragraph where it says "Click here to watch the video." (Incidentally, this is not my company.)

Not trying to be a spoilsport, but I hate to see guys get hurt or cause property damage if some simple precautions can prevent it.;)
 

ghrocketman

Well-Known Member
Joined
Mar 29, 2010
Messages
458
Reaction score
1
Mikus,
Near Miss huh ? I have heard several of those stories in the past.
Are you an ATC at a FAA ATCC ?
My father is an ATC.

I have a Libertarian philosophy in that one should be able to do pretty much ANYTHING as long as they do not hurt someone else, and NO I don't buy into that actuarian philosophy of if you engage in something you are X% likely to injure someone else. As long as it does NOT happen, in my book NO HARM ALWAYS = NO FOUL. If you hurt someone else no matter the reason or background of activity (irregardless of any baloney gubmint bogus additional tack-on garbage charges), and you are found 100% at fault, you (your insurance) are going to pay.

No danger/risk = no thrill/fun = NO THANKS !

Ever see ANY fans at a NASCAR race marvel over the level of safety equipment in a race car or be satisfied when a race has zero wrecks ? Absolutely not unless they are some sort of pencil-necked geek safety engineer. WHY ? Because it is BOOOOOOOORRRRRRRRRIIIIIIIIIINNNNNNNNNGGGGGG !

OOO BOY ! A video link from a Safety and Environment company; I'll put that on my list of "Not interested if the last video on earth"
 
Last edited:

Rutrag

Active Member
Joined
Jul 10, 2010
Messages
38
Reaction score
0
OOO BOY ! A video link from a Safety and Environment company; I'll put that on my list of "Not interested if the last video on earth"

Actually, Harsco produces preformed concrete structures, performs scaffolding services, railroad maintenance, mines, and produces industrial air handling equipment. They're not a safety and environment company any more than Estes, Custom Rockets, Fliskits, Quest, or Squirrel Works is.

If some jerk cuts you off in traffic causing them to fear for their lives to the point you have to execute an emergency maneuver in order to avoid a collision, is that no harm no foul? What if the OP set his house on fire, and that spread and burned down a subdivision?

Ignorance isn't bliss; it's ignorance.
 
Last edited:

ghrocketman

Well-Known Member
Joined
Mar 29, 2010
Messages
458
Reaction score
1
Yes somebody that cuts you off in traffic but no accident results IS in fact, NO HARM = NO FOUL, but most likely WOULD encite a JUSTIFIED case of ROAD-RAGE with henceforth justifyably RUNNING HIM INTO THE DITCH.
 
Top