Hybrid Rocket Motor Nozzle Tests

[LTF85199]

Thanks for sharing this video.. very useful

[Dragonsintuxcedos]

Is the combustion chamber made of glass?

[llllXeallll]

hello i'm new to rocket making and you probably hear this alot but where is a good site/book to go read to learn the fundamentals. i understand alot of what your saying but i wouldnt be able to figure that stuff out myself yet and i'm really interested in learning more.  Any help would be greatly appreciated!!!

[psyclistic]

A few questions:

1) What kind of steel are you using for your nozzles?

2) What's the material of your combustion chamber walls?

3) What are you using for fuel / oxidizer?

I'm an aero engineer but not an expert on this stuff. Maybe your nozzles/orifices aren't melting because there's enough thermal mass for a lot of the heat to be conducted away from the region where the steel comes in contact with the exhaust.

[noxnflame]

What is the clear tube made of in the middle of the engine? I would think glass but that melts way below the temperature it's at.

[emilen2]

Nice nough, though seriously you ought to get an F for Failing the metric system.

[Alexpaths]

@nox665 Most CalPoly engineers use metric unless specifically told otherwise. Many times we use English units since we are told to by industry such as Boeing, Lockheed Martin and Some others for presentations; have you ever had good momentum in a presentation that is brought to a sudden stop because some old engineer can't use metric? Really we want jobs.

[Alexpaths]

To everyone who has commented in regards to using metric. The professor/advisor of this project and mine is opposed to the metric system.

[Nox665]

Oh well, Sounds like both u and ur professor/advisor belong to the past :)

If the rest of the world can learn ur language, u could at very least learn the !rest of the world's! metric system.

[fookthefrench]

Your analogy is flawed. The OP and his professor know the metric system. They just didn't use it for this project.

[alejandroengineer]

The sputtering is caused by the lack of oxygen making the flame inside move to different areas, and this explains why the sputtering began to increase at the end because the burning surface area increased when the oxygen supply was the same.

[ZachreyCA]

Wow thanks for the explanation! It's like the flame is hunting around for oxygen in the chamber.

[TripingAIR]

sounds like a very interesting study are you still working on these types of projects or was it a one time thing?

[Fenrisulfir]

0,075 inches, 0,175 inches... tss these are really nice numbers to calculate with. Haver you ever heard about a thing called metric system?! Makes your life much more easier.

[EUBG]

Agreed

[nickalisse]

@Fenrisulfir Pretty good video & explanation, but I'm all with you. Metric system is lot easier to calculate!!!

[AtheistOnTheEdge]

Metricphobia.

[mrmanleedude]

good video. making another one soon?

[hansbenedikt]

Is it that hard to use N instead of these strange Ibf ?

[eamonia]

This dude gives way too much explanation. Trying to act like it's rocket science or something...

[HAL11000]

This "dude" is explaining it like it's rocket science because, um...it is rocket science.

[eamonia]

You're kidding right?

[HAL11000]

I had the same thought when I read your comment.

No matter, its irrelevant anyway.

[892snowyowl]

Don't see you building this, and why do you even watch video's like this if you are just gunna put some shit comment like that?

[eamonia]

It blows my mind that anyone took me serious and didn't catch the blatent sarcasm. Whatever. And you're right, I have no intentions of fabricating a hybrid rocket, I can afford one. What the hell do you care anyways? I was making a indirect compliment on the mans intelligence that apparently rocketed over your heads and you nosy opinionated losers just had to play Mr. Hero. The entire YouTube comminuty greatly appreciates your efforts and wouldn't be the same without you. Kindly fuck off.

[arias1772]

what is so not rocket science about this?

[Shazee083]

dude its Aerospace / Fluid Mechanics mix with Thermodynamics he explain to fast and very fast

[airoscar]

this is a senior project, he probably has to write a more detailed report.

[kondordv]

nice job, thank you!

[GlitchAttack]

exclusive job !

best wishes for you

[ALeKZanDoHr]

K3 hydrogen magnesium and oxygen is the N.A.S.A. Formula

[mikeyidh]

Hydrogen and oxygen fuel. Good choice.

[eddimbr]

I have to agree that it´s really stupid to keep using different measuring units. What about the international units system? m,Kg,s,N? anyway it´s an really interesting study but I think you should test with real conditions instead of using propane combustion chamber, specially when using solid rocket fuel that you have milions of particles coliding against the edges of the nozzle. keep it up, cheers.

[Inventor81]

units are units. If they cause you a problem, then they're obviously not your native "language". And afaik the propane is to pre-heat the fuel grain.

[lakissssssssssss]

gamo panagia

[killabilla]

you guys use lbs, inches and Fahrenheit, what a shit collage

[sumplesnoob]

Really? dissing someones education, then saying "collage"?

[killabilla]

i could have corrected it but didn't bother, just like you fuckers don't bother learning real science with SI units.

btw i love usa, but the unit thing fucking my shit up

[qsucvatz]

Cal Poly's engineering does unit conversion out of their asses - we just match what is used in industry currently for projects. We can out-convert anyone.

[Collinoeight]

That would indeed make a shitty collage...

I like collages with more pictures in them

[dudebot09]

I can imagine the shop blowing up and the narrator saying "that's a pretty standard burn"

[bali105]

Awesome stuff! I really enjoyed watching this. Im about a year off before I can start in the aerospace engineering program, but man that year seems sooo long....stupid classes I have to do beforehand!

[estevan300]

i dont understand this stuff and i am because i might want to do what your doing :D

[estevan300]

Thats awsome

[rocketman0815]

overexpanded doesnt mean flow separation...flow separation in overexpanded nozzles only occurs when the ratio of nozzle xit pressure over ambient pressure is less than 0.3 ;)

Pressure oscillations in the chamber have nothing to do with vortexes in the nozzle, because interferences in the supersonic nozzle flow can only travel downstream out of the nozzle.

[Inventor81]

did you calc re: the ratios?

area ratio up around 5?

;)

[ant1ph0n]

i think dousing everything in gasoline should make it run better, right?

[dawson01912]

So it didn't produce enough thrust at all!!!

You've just made a really big lighter, dude.

[jman51]

read the description man, the point

wasn't to produce a lot of thrust.

[dawson01912]

Yeah, and I wouldn't watch this if I knew that before reading that really lengthy desc. Whatever, this sucked.

[alancj05]

You might try increasing the injection to chamber pressure drop of your oxidizer and see if that helps the combustion instability. In other words, if your chamber is at 150 psi and the oxidizer is at 175, that's a drop of 25 psi. Raising the drop should help.

[rocketboy734]

thanks and i wasn't planing on making one soon.

[rocketboy734]

Hi I am in 7th grade and was wondering if you could answer some questions for me. did you use model rocket engines and what do you mean by hybird.I know what it means with cars but i am not sure if it is the same with this.Also i make my own model rockets and was wondering if i should use washers as my nozzels.nice video.

[johncheever123]

While I am not on this team, I am working on a hybrid rocket at the University of Michigan. A hybrid rocket is a rocket engine that uses a liquid or gaseous oxidizer and a solid propellant. In this video, the rocket uses oxygen (either gas or liquid, I don't know) as the oxidizer and plexiglass as the fuel. At UofM, we use Nitrous oxide as the oxidizer and parafin (wax) as the fuel. It is totally separate from car hybrid engines, which use electricity and gas for power.

[rocketboy734]

thanks

[rocketboy734]

do you want to be a aerospace engineer and do they give you classes about that there.

[pitbike2006]

hybrid in this turm is useing 2 fules like a car electric and petrol and thease engins ARE NO WAY THE SAME AS MODEL ROCKET ENGINE THEASE ARE BIG BOY ENGINS if you had one of thease on a model rocket u would never see it again lol i will help you in the future if you need it just email me

[plzplz12232]

Could you provide an ISP of your motor, along with you final nozzle concept. And if you please, provide a delta v.

[plzplz12232]

Could you provide an ISP of your motor, along with you final nozzle concept. And if you please, provide a delta v.

[cabagesoup714]

That is great, just the information that I needed. I am making a hybrid rocket motor, using gaseous oxygen as the oxidizer. The nozzle is the hardest part for me, I have a lot of machining experience but am too poor to buy materials other than steel. I was worried that the steel would melt, but this resured me. I don't know if you have any tips, that would be great.

[mark8v35]

Well, I would warn you that the combustion temperature stayed below steel's melting point only because the combustion pressure was so low. If you up the pressure to get any kind of decent thrust, you're going to increase the combustion temperature and thereby run a good chance of melting a steel nozzle. It also depends on how long you run it - even aluminum would last a second or two. It also depends on what you are using for the fuel... so many variables. Let me know if I can help you out.

[chaosopher23]

@cabagesoup714 Use the kind of clay that fires in a 2500* kiln that can be reheated and reheated... it's cheap, and can be machined if you're slow and careful, and it doesn't melt easily. Estes does it all the time.

[flyme1991]

that`s serious nobelprize-stuff,, cool ;)

[RatkoUSA]

Your nozzle orifices really blow.

[12gravediggers]

prety standard thrust curve 4X

[neoterranami]

Well done. What is the fuel type? What approximately are the combustion chamber pressures (about)? Is the Plexiglass a standard or modified material- what gauge thickness is it?

[bangous]

2 pounds very impressive for a model rocket motor

[laboo69]

Ever get a handle on the cause of the combustion instability? Seems to be the hybrid curse.

[irishguy20007]

What is the difference with producing a much larger rocket engine.Will the same principals apply as one sizes up or are there different principals involved.I was inspired when I was in Chicago in 1994 and seen one of the captures rocket engines at a university.

[mark8v35]

The same fundamental principles apply, although new issues are almost always introduced with scaling.

[cabagesoup714]

Thanks, I'm a pretty experience builder, but new to rocketry. I'm starting with cellulose as the fuel grain, I want to try different materials eventually. I am very aware of the possibility of the nozzle melting. Are there any good forums online for hybrid rocket motors?

[airgunsniper]

Great job! Up your o2 pressure by a lot. That will result in a huge increase in thrust but watch out that you don't decompose your nozzle or burn through your combustion chamber.

[JonRavenfield]

yay home made missiles :D

[hightechstuff2]

Very cool! What's your combustion chamber made out of? Quartz? how long can you run it like that?

[mark8v35]

The combustion chamber you see is the inner core of a Plexiglas tube. We can run this for about 90 seconds before it will burn through the sides.

[beatsiz]

Wouldnt it blacken?

[mark8v35]

It does actually blacken, but not enough to completely block the light of combustion.

[battlekingdeluxe]

cool

we build a hybrid rocket too. you can watch it in my youtube site.

[Russo017]

Cool stuff! I'll have to post my senior project as well :)

[hifeyracer]

hey im going to cal poly in 2 yrs to become an aerospace engineer is it a good school and hows the campus life? also is there a lot of handson?

[HighrockTendales]

Why not use three smaller nozzles?

[insults4u]

this is pretty good but when i went to school they did not offer rocket science

[tkktkt]

I envy people born with innately high IQ's.

[robertgissing]

great video. I also got sputtering near the end of my runs, and i think it might be because the soot build up around the inside opening of the convergent part of your nozzle is impeeding the flow. My motor did not have a post combustion zone to allow for a complete combustion of the fuel. I wonder if it is the same problem you are having with the sputtering.

[mark8v35]

Could be. I've thought about putting a post combustion zone to ensure complete combustion, but we'll see.

[tanilozkan]

Have you analysed the combustion front progression speed? The reduced O2/fuel ratio is probably caused by the fact that the combustion front progression speed is slower than the flow speed of the fuel. Include also a tiny CO sensor next time, it could be interesting to see the degree of combustion.

[mark8v35]

Hmm, interesting. Why would the flow speed of the fuel be lower than the speed of oxidizer at injection?

[simonhorwell]

poor mixing of the fuel and oxygen as well as fuel/oxidiser turbilance into the combustion chamber can cause spluttering.

[Nemesis00243]

Very Complex project nicely put together! Bravo have yout tried any other rocket propellants?

[mark8v35]

We are planning on testing the motor with N2O (Nitrous Oxide) as an oxidizer as soon as I get back to school. It should be fun!