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Could estes engines be used in space?

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rabidsheeep

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Im curious... Could they? Or would they need the oxygen to actually begin burning. I dont see why they wouldn't?

Anyone?

:)
 

BlueNinja

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I don't know too much about chemistry.... But here's a shot.

I think the potassium something or other (can't remember that second word, i mean KNO3 however) provides the oxygen when it burns. AP motors, i should say composite in this case, have the Ammonium Perchlorate which is the oxidizer.

If any information here is incorrect, please correct me.


Blue
 

DynaSoar

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Originally posted by rabidsheeep
Im curious... Could they? Or would they need the oxygen to actually begin burning. I dont see why they wouldn't?

Anyone?

:)
They would start fine. However, they would not have exactly the same effect.

Look up Team Extreme's Aurora Project (was on Discovery Channel's Rocket Challenge). They had to research how black powder worked in a vacuum in order to figure out their recovery system.
 

rocketdad0934

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which is why they used the co2 cartridge ejection for the recovery system. I don't remember all the particulars except that it woould not burn correctly or creat the proper pressure at the altitude.
 

DynaSoar

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Originally posted by rocketdad0934
which is why they used the co2 cartridge ejection for the recovery system. I don't remember all the particulars except that it woould not burn correctly or creat the proper pressure at the altitude.
Not the pressure, but rather the shock wave -- the pressure interacting with the ambient pressure for form a sudden increase. The vacuum would "suck away" at the pressure front faster than it could build, or at least so fast that they couldn't be sure of enough pressure fast enough giving the kick that they needed.

They *did* use black powder, and it worked for its intended purpose, to make the CO2 system go.

Actually, I found the paper they wrote about it.
Word format.

Aw crud. Not a valid file type.
Well, someone tell me how I can make it available here, or else do a Google search for their site.
 

n3tjm

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Black powder rockets do work in space. Matter of fact, I think I read somewhere that they launched a model rockets in space on a shuttle mission?
 

mikeyd

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The black powder for the Aurora did not use an oxidizer, so at the altitude it was at, it would have a hard time burning completly. The Estes BP include an oxidizer, and I have seen a test that would prove they work in space! If you are ever in Hutchinson KS. I recomend that you go to the Kansas Cosmosphere, and specifically watch and exibit called "Goddard's Workshop" In this Workshop they teach principles of rocket flight, one of these is to launch an Estes rocket inside a clear PVC pipe with all of the atmosphere removed. IT works just fine.

Happy Flying!
Mike Dickinson
 

n3tjm

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Originally posted by mikeyd
The black powder for the Aurora did not use an oxidizer, so at the altitude it was at, it would have a hard time burning completly.
Um, Black Powder is a Monopropellant. That means it contains its own oxidizer. In Black Powder's Case, it is Potassium Nitrate. I am not sure what the issue with the aurora project was...
 

Const Star

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like they said, its the reason nasa uses gas bursts to manouver in space. lack of oxygen kills a fire which thrives on eating oxygen to survive
 

DynaSoar

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Originally posted by mikeyd
The black powder for the Aurora did not use an oxidizer, so at the altitude it was at, it would have a hard time burning completly.
You must have misheard or misread something.

If it didn't have an oxidizer, specifically potassium nitrate, it wouldn't be black powder. Black powder is ~75% KNO3. Without it, it would be 3/4 charcoal and 1/4 sulfur, and wouldn't burn at all.
 

DynaSoar

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Originally posted by n3tjm
Um, Black Powder is a Monopropellant. That means it contains its own oxidizer. In Black Powder's Case, it is Potassium Nitrate. I am not sure what the issue with the aurora project was...
I don't think monopropellant applies. I think that's when a single chemical compound is used and interacts with a catalyst that causes a breakdown reaction from that single chemical to exhuast products. Like 2 H2O2 --> 2 H2O + O2. BP still has an oxidizer and two fuel components even though it's mixed to homogeneity.


Here's the text from their paper on testing BP for Aurora.

I decided plain text was fine because of the three referenced graphs on the paper, there is graph #1, two graph #2, and no graph #3. Graph #2 is attached.

====================================

When Aurora was envisioned, Dad, Pat and I knew we would need to come up with some alternative to black powder deployment. The record for large high altitude rockets is not good. Ballistic recovery seems to be a common occurrence. Given the skill of the rocketeers involved, something other than carelessness is at work. That gremlin is air density. In the standard atmosphere model, at 30,000 ft the air is 27.6% of the density at sea level. Not only is there just 28% of oxygen available, but more insidious still, there is only 28% of air mass for the expanding black powder gases to expand against. Exploding black powder does NOT create enough gas to fill the empty spaces of a larger rocket all on its own. Pressurized liquid CO2 can provide the needed gas, and it can be packed in a nice small package.
_
Soon after we began spinning our brains on the problem, we came upon the CD3 system developed by Tom Rouse. This was the perfect type of system to do the job. However, the CO2 cylinders that were compatible with his method were way too small for Aurora (Tom has since added bigger CO2 cylinders.) Being an avid paintball player, I knew of just the thing; Paintball CO2 canisters. After a little hunting Dad found pre-filled 4oz one-time-use CO2 paintball cylinders at Wal-Mart. After machining our own copies of Tom Rouse’s CD3 that would fit the bigger threads we had the perfect system. Now it was time for testing, testing, and more testing. I’ll spare you the blow-by-blow account of our experiment and skip right to the findings. This is what you need to make your own rocket work anyway, eh?
_
CO2 works slightly different from black powder. There is one more variable at work and that variable is time. You can ignore this factor and everything may work out great. Or it may not. To understand, let’s start by looking at how black powder does its job.



Imagine a sealed rocket using black powder. Graph 1 shows the internal/external pressure difference vs. time. Because black powder acts so quickly, it’s as if the internal pressure just instantly jumps from zero to Pmax (The graph trails off after Pmax because of the vent hole.) As long as the pressure required to remove the nosecone (Pnose) is less than Pmax, everything is hunky-dory. Pmax is NOT effected by the size of the vent hole (unless its way way big) However, Pmax is not the same at every ejection altitude (see Graph 2.) It may not take much altitude to reduce your Pmax below Pnose. You can increase the size of your charges but how are you going to get to 30,000 ft to test whether you have enough?_ Even then, as Pat has told us, the BP won't burn completely after certain volume levels. Now let’s take a look at a CO2 system.

Using the same sealed rocket, Graph 3 shows the internal/external pressure difference vs. time for a typical CO2 system. Our pressure still changes from zero to Pmax at the ejection event but now it takes a measurable time for this to occur. The delay comes as the liquid CO2 evaporates into gas and vents out of the cylinder. The typical vent time for Aurora’s 4oz cylinders is .1 to .5 seconds. The crucial fact for high altitude rockets here is that Pmax is NOT dependent on altitude (it actually does vary slightly but it is a negligible amount.) Because your vent hole will be trying to reduce Pmax during the vent time, you must get the balance right so that Pmax is greater than Pnose. Fortunately, you don’t need to work out any complicated equations to get your CO2 system to work. All you need do is test your flight configuration. With CO2, IF THE NOSE WILL COME OFF IN A GROUND TEST, IT WILL COME OFF IN THE AIR. In practice, the main problem is that your nose will come off TOO easily before internal pressure has built up. You will likely want to restrain your nose in some way. This will allow the pressure to build enough so that the nose “pops” off with force. (It does so within .25 seconds)
If you ground test your CO2 ejection you will not need to work any equations. However, in the process of tweaking your rocket deployment system you may find some of the following equations and relations helpful.
_
First remember the general relation F=PA (force = pressure * area)
_
You may also want to note that
h=V0t – ½gt2
Where h= height nose cone will be ejected above the rocket.
V0 = velocity nosecone leaves the body tube.
t= time nosecone takes to accelerate off the coupler shoulder.
g = acceleration of gravity (9.8m/s2)
_
This last relation is not very useful because V0 and t are not known. However if you throw in the ballistic relations V=at and x=1/2at2 you can come up with something much more useful…
_
h = 2s –gsm/PAn
Where h= height nose cone will be ejected above the rocket.
s = length of coupler shoulder
g = acceleration of gravity (9.8m/s2)
m = mass of nosecone
P = internal pressure differential
An = Cross sectional area of nosecone base
_
This last equation is exactly what we used with Aurora. We started with the assumption that we would need the nosecone to “pop” off at least 5 feet. Using this last equation we then found the required internal pressure. From F=PA we could then say exactly how much force we needed to restrain the nosecone with.
_
One last word about these equations; Use only metric values (any guesses what the English unit of mass is? One clue. It’s not pounds) and convert everything to consistent units. I recommend meters, seconds, kilograms, and their derived units like m/s and newtons (kgm/s2)
_
So there you have it. The maximum ejection pressure from black powder varies with altitude but provides a nice instant shock load that is very forgiving of variations in your restraining nose force. CO2 maximum ejection pressure does NOT vary with altitude but has a measurable venting time that causes a concern not found with BP. However, CO2 has some nice benefits like non-corroding waste gasses and reproducible flight conditions at sea level. If it will work on the ground using CO2, it will work in the air.
 

Ryan S.

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the reason BP charges dont work in space is the lack of pressure to hold the charge together while burning is still under way. So, what you get is unburned particles flying every which way, and not complete burning, therefore not as much pressure. Some people have just used bigger charges, while others have contained them

There is no reason a BP motor wouldnt work in space, as inside of the motor is not effected by the vacuum, except for the pressure being slightly lower inside. Other than this the motor will still burn.
 

DynaSoar

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Originally posted by Ryan S.
the reason BP charges dont work in space is the lack of pressure to hold the charge together while burning is still under way. So, what you get is unburned particles flying every which way, and not complete burning, therefore not as much pressure. Some people have just used bigger charges, while others have contained them

There is no reason a BP motor wouldnt work in space, as inside of the motor is not effected by the vacuum, except for the pressure being slightly lower inside. Other than this the motor will still burn.

What you say would hold true for loose and uncontained BP, but it's not the only problem with using a BP charge. Having no air to pressurize into a shock wave is also a problem when it comes to ejection. It's not the gasses from the BP that blow the nose off, it's the pressure wave caused by those gasses expanding some distance away, fighting against the countering air pressure (or lack of) keeping the nose on. Contained BP would burn OK, but when the container burst there'd be nothing for it to pressurize and the gasses would get sucked away faster than a front could form, by the vaccuum.
 

bobkrech

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There's a lot of technically incorrect statements in this thread.

1.) By definition, a rocket motor that supplies thrust based on chemical combustion does not need atmospheric oxygen to funtion, as it contains both an oxidizer and a fuel. A motor using hot gas to supply thrust operating by the combustion of a fuel with atmospheric oxygen is a jet.

2.) Black powder not a monopropellant. It is a solid propellant mixture as it at a minimum, contains both an oxidizer, Potassium Nitrate, and a fuel charcoal. Monopropellants are molecules that rearrange to form hot gases.

H2O2 --> H2O + 1/2 O2 + heat , N2H4 --> N2 + 2 H2 + heat (oversimplified), etc.

3.) BP motors will work just fine in space. The issue is not operation, it is ignition. Hot Gas is required for the heat transfer needed to initially ignite the fuel grain. At low altitudes, below 20 Kft, there is enough air to perform this role, above 20 kft, you need to have a hermatic ignitor/hot gas generator to perform the ignition function. This fact has been known for more than 60 years.

4.) BP works just fine for high altitude deployments systmes as long as it is initiated in a hermatic container. People that claim that you can not use BP to deploy recovery systems at altitude simply have not bothered to read any of the aerospace engineering hanbooks that describe the processes and hardware designs in detail.

5.) Shock waves have nothing to do with motor ignition or parachute ejection.

The combustion processes inside the motor thrust chamber are subsonic. If something goes wrong and you get supersonic combustion within the motor chamber, a detonation is occuring and the motor will dissamble in milleseconds.

BP is a low explosive by defination and deflagrates (burns fast) and generates hot gases. It is the generation of these hot gases and the resulting pressurization of the deployment compartment that provide the force to activate the deployment system.

6.) Cold gas thrusters are often used for attitude correction systems becasue they very simple and do not require an ignition system. They only require a high pressure gas tank, a pulsed solenoid valve and a nozzle. They have very low specific impulse and low thrust, but that all that is required for attitude control.

There's a lot of good technical information posted at various educational web sites. Apogee's education webpage http://www.apogeerockets.com/education/index.asp has links to many of them. I wish the folks responding to this and other threads would simply do a google search on the topic being discused before they post to insure that the information they are posting is correct.

Bob Krech
 

r1dermon

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so would the standard pyrogen dipped igniter work in space? i dont see how it wouldnt, it is ignited electrically, but i dont know much about pyrogen, it would seem that it doesnt need air to ignite and burn, whats the accuracy of that assumption?
also, bob, i've seen a couple posts of yours with these BP containers cited in them...is there a link where i could find out more? i've been interested for a while, and i couldnt find anything on them, it would just seem to me that any contained BP would detonate its container at more than sonic speeds thereby destroying its vehicle.
 

Micromeister

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Hoooo! Get em Bob!
Saved me a bunch of typing;) Perfect example of what those
Advanced topics guys were squawking about. Misinfo spread and quickly corrected... Nicely, Pleasently and concisely. TRF Mods policies vindicated once again:D
 

bobkrech

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r1dermon

From my previous post:

"The definative reference on solid rocket motor igniters, complete with the details of heat transfer, pyrogen chemistry, and mechanical design as well as a large number of technical references, is found in NASA SP-8051 Solid Rocket Motor Igniters. This is the source where most of the information in Sutton's subchapter on igniters came from.

It can be download at http://trs.nis.nasa.gov/archive/00000094/ and is a must read for anyone who wants to know how professional solid rocket motor igniters and ignition systems work."

A pyrogen is a material that make fire and heat. Pyrogens may or may not generate hot gases, however you need hot, high pressure gases to ignite a rocket motor in space. A pyrogen dipped ignitor would operate in space, but it would not ignite a motor unless boosted with a BP or similarly combustable hot gas generator.

A typical dipped ignitor has 2 components: a real or virtual bridge wire and a pyrogen.

A real bridgewire is simply a very fine wire that will get hot when current passes through it because the resistance is high, and it generates power acording to the equation P = I^2 R. The heat generated by the power dissipated by the hot wire ignites the pyrogen which generates far more heat due to the reaction of the fuel in the pyrogen with the oxidizer in the pyrogen.

If the pyrogen uses a conductive polymer as the binder, the resistance of the conductive polymer acts as a virtual bridgewire and it dissipates power and heats up as current is applied. Once it gets hot enough the chemical combustion take off in the same manner as described above.

The pyrogen usually contains at minimum, a metal and a metal oxide and a binder to glue it all together.

The normal use of a pyrogen dipped ignitor is to set off the BP lifting charge in commercial fireworks. This is how it works. (I'm not giving the percentages so you won't be able to make it, nor will I violate the TRF policy on publishing pyrotechnic formulations.)

A typical binder might contain vinyl resin, nitrocellulose lacquer, dibutyl phthalate, and acetone. The solvents evaporate and you are left with a flexible combustible binder that keeps the pyrogen together.

A well known pyrotechnic pyrogen contains potassium perchlorate, potassium chlorate, charcoal, magnesium powder, red iron oxide, aluminum fine, sodium bicarbonate (the chlorate make this mixture very sensitive and really shouldn't be used)

In this pyrogen, the bridgewire heat causes the chlorate and perchlorate to burn with the charcoal which generates enough heat to ignite the magnesium which in turn produces enough heat to decompose the iron oxide and burn the aluminum, and make molten iron. The binders also burn and generate some gas which disburses the molten iron into the BP and ignites it and the deflagration begins.

Please note that dipped ignitors were first used to ignite BP pyrotechnics. BP is much easier to ignite than APCP. A lot easier.

When you use dipped ignitors to ignite APCP, the molten iron sticks to the APCP grain and the grain starts to smolder. If the ignitor is small, there may not be enough iron particles generated to get enough smoldering going to ignite the fuel grain. If there's barely enough iron and thus heat release, it may take several seconds of smoldering before the motor catches and the rocket lifts off. If there's too much pyrogen for the volume of the void, the gases generated when the pryogen is burning will blow the ignitor right out of the motor.

The point of this discussion is to illustrate that while you can ignite a APCP motor with a dipped ignitor, it is by no means assured or prompt. Dipped ignitors work reasonably will in smaller composite motors where the length of the grain is short and the internal volume is low. As the motor size increase, prompt ignition with a dipped ingitor is less assured. From my personal observations, they do a good job on H and I motors, but can start to get iffy on K's and above, and the reason for this is that a dipped pyrogen ignitor alone doesn't generate the large volumes of hot gases that are required for prompt ignition of larger motors with large internal volumes.

Commercial and military solids are ignited by ignitors burning BP or a similar low explosive propellants at the head end of the engine. This generates a lot of hot gas which pressurized the motor and ignites the entire length of the fuel grain simultaneously. These ignitors have two components, a first fire pyrogen like the dipped ignitor which in turn ignites large flakes or grains of BP or similar propellant which generates large quantities of hot gas for one or two seconds. Ignitors like those make by Quickburst operate in this manner.

If you read the reference above, you may get more information than you need, but at least it will be correct information.

Bob Krech
 

rocketsonly

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Originally posted by rabidsheeep
Im curious... Could they? Or would they need the oxygen to actually begin burning. I dont see why they wouldn't?

Anyone?

:)
Isn't oxygen required for combustion?

And surely you don't plan on sending rockets to space with Estes motors, right? ;)
 

n3tjm

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I stand corrected. I thought monopropellant was a propellant that had a built in oxidizer. I guess I got the description confused.
 

sandman

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Yes, they would work in space.

I don't understand the complicated "stuff" in the one reply!:confused:

Or rather why it was said...

The question was "Could Estes engines be used in space?"

They are black powder...KNo3, Sulfer and Carbon...Black Powder!

KNo3 is the oxidiser, when it gets hot enough it gives off it's oxygen and that combines with the Sulfer and the Carbon.

WOOSH...a rocket motor!

The trick is getting a hot enough igniter in the cold vacuum of space to get it to ignite.

Yes, it could work in space!

Would you use them in space?...I don't think so...there are better motors available.
 

wwattles

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Originally posted by sandman
Would you use them in space?...I don't think so...there are better motors available.
And think of all the permits you'd have to have to transport them and store them! :eek:

But seriously - this is something I've always wondered about as well. I guess I always assumed that they would, but also assumed that the mass-to-power ratio just wouldn't be worth it when there are far more efficient things available.

WW
 

rstaff3

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How many treaties would you break my storing those weapons in space? :rolleyes:

Thrusters need to be throttled.
 

edwardw

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Originally posted by rocketsonly
Isn't oxygen required for combustion?

There are Flourine/Hydrogen liquid rocket motors.


Edward
 

wwattles

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I suppose that just about any chemical reaction that involves a product that includes a release of energy and a mass to eject and initiate Newton's 2nd and 3rd laws could be used in an ideal environment. We commonly use BP and APCP because they are nice and stable and give a pretty good bang for the buck, if you'll pardon the innacurate expression. Burning happens to be the means through which our products are released as gasses (and a few solids/liquids), but I would think that there are other "non-burning" reactions that would work as well.

I'm sure there are hundreds of combinations that are lighter and more energetic, but also a lot more difficult to produce, more costly to prepare, and more dangerous to store.

WW

Disclaimer: The above observations are based entirely upon conjecture stemming from a limited exposure to physics, chemistry and engineering during my life as a student over 8 years ago.
 

r1dermon

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there are alternatives, however, as bob krech told me on a PM a while back, solid rocket fuel is pretty well known, and we've basically reached the peak impulse that a solid propellent can create. thats why even NASA uses it still, so does the military.
 

buzz

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huh.... If I launched my Estes rocket from the moon
how far would it go?!:D
 

rabidsheeep

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actually this whole question sparked up when i was showing my friend fliskits.com and we started talking about tour de duece and he said "so wheres this thing gonna end? up in nasa launching off a space shuttle"

:p
 

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