Alt innom Rocketry

[esa]

Hei, dette er den nye side til å diskutere alt innom rocketry og håper at folk kan få hjelp med spørsmålene sine...

 

Men jeg foretrekker at jeg snakker engelsk, fordi jeg er egentlig fra Canada (kom her nesten 3 år siden) og det tar mer tid for å snakke norsk Jeg også tror at det vil bli lettere å forstå meg, fordi jeg vett at folk her forstå engelsk ganske godt.

 

But back to rocketry...

 

 

 

I have a big interest in rocketry, and mostly anything to do with science. I have plans of building a Liquid Rocket Engine, running on gasoline and oxygen gas. Although not actually putting it into an actual rocket (mainly because of the added complications), I will be ground testing it, for experimental use.

 

Liquid Rocket Engines are very complicated and dangerous, so I would be have to be reading up a little more until I am ready to build one. It is also expensive (hence manufacturing, propellant, etc), so I won't want to mess it up the first time. Here is the LINK of which design I plan to follow (I also realize that I have to convert it into metric units).

 

I will be constructing this LRE (Liquid Rocket Engine) sometime in the future, and will have pictures and videos of the test fire. Although not having as much thrust as a SRM (Solid Rocket Motor), it can burn for a long time with a temperature at around 3000 degrees Celcius and also generating a lot of noise.

 

However before the construction of the LRE, I plan to make some rockets using solid rocket motors. This probably being in the summer, when I have more time (tests in VGS). With those rockets I plan to experiment on different materials, nozzle designs, and propellants. So I am open for any ideas you guys might have...

 

 

 

Here are some links of all you need to know about rockets (If you don't know so much already):

 

Rocket Equations/Propellents

Rocket Equations (Easy version; also equations for height, speed, stability, etc.)

---//--- and including a variety of Rocket Engines

Experimental Rocket Propellants for SRMs

 

I urge people to understand at least some basic concepts of rockets before attempting to build any type of rocket (which should be a given ).

There are also many cool sites that have videos of rocket launches. Here are some cool links I have found today:

 

An average looking rocket that reaches space! To acheive this is insane, although it was made by NASA, so yeah...

INSANE SPEED! (click on LOSAT movie)

Some other cool High Power Rockets

 

 

 

Right now I am busy getting all my equations in order, for my future LRE design. I can post my design plans and calculations out here, if you guys wish. Any feedback would help...

 

I am also wondering, does anybody out there have any plans of building a rocket?

 

esa

[varmit]

har masse planer om å bygge raketter,har veldig lyst til å montere høydemåler på. har planer om en to meter høy rakett med mange kg brennstoff og en ladning som eksploderer,som jeg håper å få se oppe på himmelen. har funnet et bilde på google av noen raketter,vet noen hvor man kan få kjøpt slike for gjenbruk?

har ikke prøvd noe med bensinmotor,men med kno3 motorer.

men planen er å lage en 2 meter høy rakett med helst noe elektrisk utstyr(høydemåler,fart,0-100km/t osv).

men her er bildet jeg fant,så kan dere ta en titt på det:

[esa]

har masse planer om å bygge raketter,har veldig lyst til å montere høydemåler på. har planer om en to meter høy rakett med mange kg brennstoff og en ladning som eksploderer,som jeg håper å få se oppe på himmelen. har funnet et bilde på google av noen raketter,vet noen hvor man kan få kjøpt slike for gjenbruk?

har ikke prøvd noe med bensinmotor,men med kno3 motorer.

men planen er å lage en 2 meter høy rakett med helst noe elektrisk utstyr(høydemåler,fart,0-100km/t osv).

men her er bildet jeg fant,så kan dere ta en titt på det:

5976059[/snapback]

 

 

 

There is no need for measuring devices. You can easily find out the speed, acceleration, and height by using some rocket equations. Although you would have to find out some stuff first like how fast the propellant is burning and exiting out of the nozzle, etc. The second link I put up in my first post has that information, it might be hard to figure it out but its possible; you can also ask me some questions if you like.

(There is also a simple way of measuring the height and thus speed of your rocket while on the ground, by using a protractor and tape measure and some trigonometry.)

 

So far, this reducts the weight of your rocket, thus increasing the max height (apogee) of your rocket flight. I like your idea, although you might have to research a bit more about how you will make it "work". You can also buy rocket motors, then design your own rocket shell (which is also much easier and safer ) and the thrust, specific impulse, and burn time is already figured out and shown on your motor. However I haven't seen big rocket motors like the ones you need and I've heard you need lisences for them.

 

Your project seems very interesting and it would be cool to see it go up (and maybe explode? ). I don't know so much about electronics, so I wouldn't know what you would put into your rocket, but I'm also wondering if you would buy a rocket motor or design one?

 

esa

[kyrsjo]

Vel, måleinstrumenter er jo greit for å skjekke at ting oppfører seg som beregnet - du kan regne så mye du hvil, men hvis raketten din er ustabil eller ikke oppnår så stor fuelspeed som den skal, så kan du få en indikasjon ut i fra målingene.

[esa]

I don't think the speed would be a problem, rockets go pretty fast.

 

Although it would be nice to know the exact forces being applied to your rocket (and compared with your predictions), but what kinds of measuring devices are there and where could you get them?

 

esa

[varmit]

nei,den raketten var bare en tanke. må lage motor og resten av den selv,og regne ut diameter,vekt osv. men små PVC raketter har jeg jo prøv før,men opp til en kg brennstoff. kunne godt tenkt meg å vite mer om fart/høyderegning/osv.

[esa]

nei,den raketten var bare en tanke. må lage motor og resten av den selv,og regne ut diameter,vekt osv. men små PVC raketter har jeg jo prøv før,men opp til en kg brennstoff. kunne godt tenkt meg å vite mer om fart/høyderegning/osv.

5981726[/snapback]

 

I would recommend you buy a small rocket, with a rocket motor that fits it, because they have already calculated the thrust and impulse (making the equations MUCH EASIER). This is how I started, buying a cheap rocket you can find in various hobby shops in Norway and testing the height, speed, etc. (some products say the top height that the rocket can reach with a specific motor, which you could in turn compare results).

 

Use this LINK to look around and find the equations for height, speed, etc.

I will also post up two pages, one of the formulas and one being example calculations (being my results from my rocket motor: B6-4), later in the week.

 

 

 

The reason I suggest that you read that link is that it gets confusing when building your own rocket engine/motor (btw a rocket engine is a Liquid Propellant Rocket, and a rocket motor is a Solid Propellant Rocket; to spot the differences).

Right now I have many types of equations for finding the thrust and impulse, specific heats and chamber pressures, and the list goes on...

 

Anyways, I will try to find my results of my rocket and post them up...

 

esa

[Ozelot]

Siden dette er en tråd for alt innen rocketry, så lurer jeg på følgende:

 

Hva er enkleste løsning for laging av "rakettmotor" på et radiostyrt elfly ?

 

Trenger ikke å være så banalt rask , men hadde vært litt kult med to raketter på hver side som ga litt røyk\lyd fra seg da de var aktivert.

[varmit]

skal ikke avbryte spørsmålet ditt.men tanken er kul. tenk å kunne trykke på en knapp så to raketter fyrte flyet av gårde i en fin fart!

har prøvd det samme med en radiostyrt bil,koblet 2 små raketter jeg hadde lagd selv i papp med dyse av mørtel,og koblet tenneren til styremekanismen til bilen.

satte den fra meg på en slette,kjørte litt frem med vanlig motor og tente raketten. svisj! den for av gårde i en enorm fart,og begynte å snurre rundt etter ca 30 m.

men har ikke noe direkte svar på spørsmålet ditt,noen andre?

[Ozelot]

Raketter @ Elefun

 

Kanskje dette hadde vært noe ?

 

[esa]

Yes, those are model rocket engines, which I guess you could use. However you must remember those pack a charge at the end of the burn, which is meant to pop out the parachute. The explosion isn't that big, but I don't know how it would effect your model airplane...

 

It would be easiest to buy one, but you could make your own small rocket motor. If you are, then try to add more fuel then oxidizer (not getting enough oxygen, producing more carbon) you should get black smoke, but this also looses propulsion (but I don't think speed is important in this situation).

 

KNO3 which varmit has used as a solid propellant is Potassium Nitrate (Nitrogen + O3 = Nitrate), and uses sugar as an oxidizer. It should be a 50/50 mixture, but you use more fuel or less oxidizer like 60/40 (60 fuel 40 oxidizer) you will get a thick black smoke.

 

 

Btw the Estes rocket motors (including almost all commercial rocket motors) are catagorized by (example: B6-4) B being double the total impulse of an A motor, the 6 showing that the motor has a thrust of 6 Newtons and the 4 being the time delay in seconds in which it will 'pop' the parachutte after the burn.

 

esa

[varmit]

kjempeside! men slik som denne raketten,er den påfyllbar med kaliumnitrat/sukker brennstoff?

hadde jo vert kjempe det.

[esa]

Haha, of course it could "work", but I doubt it could go higher then the actual rocket motors you can buy (max performance and safety). Refilling too? I personally don't know how you would do that, I would have to experiment first.

 

Although I know someone who made a very "simple" form of a rocket. He used some potassium nitrate and sugar, mixed it togethor and rolled it up into a wet newspaper (wet making it less reactive, safer). He then put it in a steel pipe, poked a hole in the bottom and launched it. It just went up and up he said.

HOWEVER, this guy is a little crazy, although very intellegent (he is an inventor), I wouldn't recommend you doing this the same way. He has just told me what he has done, I haven't actually seen it.

(Although we made a big balloon out of plastic bags, and when done it had unbelievable power. It went up and up, because of the thick black smoke inside the see-through plastic was heated by the sun)

 

Here is a LINK to some various solid rocket propellants, if you want to know more about that...

 

esa

[Ozelot]

esa: regner med negativt svar, men spør allikevel:

Kan jeg bruke bensin eller den metanolblandingen jeg bruker til rc-biler\båter\fly ?

 

 

 

Dette vil vel eksplodere, men finnes det en måte en kan få dette til å brenne saktere og heller blåse ut et rør ?

 

(som f.eks. en jetmotor)

Endret 25. april 2006 av Ozelot

[esa]

esa: regner med negativt svar, men srpør allikevel:

Kan jeg bruke bensin eller den metanolblandingen jeg bruker til rc-biler\båter\fly ?

 

 

 

Dette vil vel eksplodere, men finnes det en måte en kan få dette til å brenne saktere og heller blåse ut et rør ?

 

(som f.eks. en jetmotor)

5985882[/snapback]

 

 

Well, first of all you need to make a nozzle, or you can't make anything 'move' because inside the combustion chamber of a rocket, there is high pressure low velocity mass, and at the exit of the nozzle its low pressure high velocity mass. This is how a rocket actual works.

 

Second, how are you going to pump the fuel and oxidizer into the combustion chamber? The simplist form of a liquid rocket engine is a pressurized system (others are with complicated pumps, turbines, etc.), the faster the fuel/oxidizer gets to the combustion chamber, the more 'speed'. You can't make it burn 'slow' unless you can get way more mass out of the rocket. The mass and speed are proportional, and you have to go into thrust and impulse.

 

So far you have way too much weight, and I haven't even gotten into the specific heats of metals you wish to use, propellants, or even the dangers.

Although I don't mind you asking, because this is what the forum is for.

 

Btw the only difference between a rocket and jet engine is that a jet engine is an 'air-breather', getting oxygen thats in the air through the turbines. A rocket on the other hand has oxygen on board (this being the so called 'oxidizer'), so a rocket stores fuel and oxygen on board, thats also why rockets can travel in the vacuum of space and why jet engines can't.

 

So in conclusion, trying to make a liquid rocket engine (which I plan too) is just way to complex and expensive. Although it is a little bit safer then an actual solid rocket motor. It is possible to use a methonal mixture, but there are so much other propellants that are better.

 

 

If I were you I would either buy a solid rocket motor or make one myself. A solid rocket motor is excessively easy compared to liquid rocket engines. It depends on what you want to acheive...

 

Any other questions? I hope I haven't discouraged anyone, but I'm just saying how it is

 

esa

[Ozelot]

If I were you I would either buy a solid rocket motor or make one myself. A solid rocket motor is excessively easy compared to liquid rocket engines. It depends on what you want to acheive...

 

Any other questions? I hope I haven't discouraged anyone, but I'm just saying how it is 

 

esa

5986231[/snapback]

 

Får vel bare sette en fyrstikk borti det da.

Det er noe gammelt drivstoff som er altfor gammelt til å bruke, så får heller bare sette en fyrstikk borti det og filme det

[esa]

Haha, thats one way to do it But I wonder if you add something more and make it into some type of sludge? Then see if it is flammable. You could even add some sort of oxidizer, then pack it tightly into something and see if it explodes...

I guess thats one way to find out new types of propellant

[varmit]

noen putter jo kalium-permaganat(kmmo4?)i drivstoffet,for ekstra oksygen.

litt svovel skal være bra,har ikke så god greie på det jeg.

[Ozelot]

Vil ikke dette lage en eksplosjon ?

 

 

Edit:

Kannen er tett.

Endret 25. april 2006 av Ozelot

[varmit]

tenker du på vanlig bensin,er min tanke at det vil brenne bra. lunta brenner hull i tanken(om den er av plast). Det jeg ville gjort er å legge en bombe nedi,noe som eksploderer i alle fall. da vil du få et smell pluss en fin sopp-flamme:)

Du kan også legge mange glassflasker med bensin(tettet) i en søppelpose og hive noe brennbart nedi,f.eks en hyler/brennende papir osv. Kast den av gårde og "run to pieses"