Alt innom Rocketry

[varmit]

Åhh!!

Dette er noe av det råeste jeg har sett av motorer,bare se denne O-motoren her:

 

[esa]

Åhh!!

Dette er noe av det råeste jeg har sett av motorer,bare se denne O-motoren her:

 

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I've seen that before

 

By the way, the thrust is measured in either pounds, kilograms or Newtons and is the result of the excerted pressure (aka "power", which I guess you can say). The specific impulse is the time (in seconds) to which the rocket engine provides a thrust equal to the propellant consumed. The total impulse (measured in Newton seconds, or pounds/kilograms a second for that matter) is kind of like "velocity = stretch / time", but is expressing how much thrust a rocket can produce in a given time frame. As I said earlier, the motor classes are measured in total impulse. That being that a rocket can have very little thrust, but a long burn time, and have the same total impulse of that of one that has a high thrust and short burn time..

 

I hope I have explained it so you can understand, but here are some pages that can explain it way better then I can...

Richard Nakka (in the "Theory" section)

Rocket and Space Technology (in the "Rocket Propulsion" section)

 

esa

[varmit]

Ok,so when it stands pound seconds,that means how much "power" the rocket produce?

 

I also have a film of an P-motor thet produse 78.000 newton!

[esa]

Ok,so when it stands pound seconds,that means how much "power"  the rocket produce?

 

I also have a film of an P-motor thet produse 78.000 newton!

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Well lb/s (also can be kg/s or N/s) is the impulse. Which is the thrust (in lb, kg or N) a rocket produces over a time (in seconds). Like the space shuttle's SRBs produce 11 000 lbs of thrust a second. Thrust is the "force", which is what I believe is what you are looking fore.

 

Oh, and I can explain why the Specific Impulse is measured in seconds. First of all, the Specific Impulse is how many N-s/kg (aka lb-s/lb or kg-s/kg) a rocket produces. As you see the "weight" cancels each other out, leaving behind the "seconds". That the specific impulse is the time (in seconds) to which the rocket engine provides a thrust equal to the propellant consumed. It is a little confusing, even I need to think through it a little

 

With the P-class motor, I think you mean 78 000 Newton-seconds

 

esa

[varmit]

yess,newton seconds.

So,it is just many ways to explain the "power"?

But if you calkulate over it,you could also messure the thrust in horsepower?

(75 kg 1 meters up in 1 second)

 

I am planing to make an PVC-motor in I-class,drawings from nakka-roketry.

Witch way is the most used for explaining thrust, Newton-seconds?

And,witch motor is the biggest one you ever built?

 

I am planing to build an rocket to put my I-motor into,sould I build that after drawings too?

[esa]

Haha, well explain to me the power of a car It depends what you mean by power, it could be horsepower or torque for that matter. I think the thrust is the "torque" and the specific impulse as "horsepower" When doing things in rocketry, use the terminology in rocketry. Don't think of horsepower and stuff, it just gets extra confusing

 

I can explain some more, and maybe make some examples later...

 

esa

 

EDIT:

 

I have only built one motor so far (h-class), but am making another one (k-class). Plus I have just made some homemade cardboard for which I am going to use as an air-frame for my first motor I made, plus everything else for building and finishing the actual rocket. I will post more details when I have time

 

When you build your motor, follow Nakka's drawings EXACTLY That way you don't have to worry about anything else, because all the calculations have been done. For "power", look at the total impulse for the total "power" the rocket can give, the average thrust (force) multiplied by the burn (time) will give you the total impulse (work). Just remember though, keep your focus on this rocket motor your building! You won't get anywhere if you don't focus on one project

 

You should be concentrating on where to find the materials in order to copy Nakka's design. Replicate his design as best as you can, then you can look more into the math When you test-fire it, you will get a feeling for what is meant by power. You can also test how many Newtons it does with some devices, then you find out the thrust of your rocket (aka "power")

 

esa

Endret 9. september 2006 av esa

[varmit]

Do you know where I can buy the materials I need?

I am also going to build a rocket that my motor fits, but first the motor.

I will take it step by step, so I don't do anything wrong.

I also have to make the thing I fill with propellant( den formen)

 

There will be bigger motors later,but have to make some small motors and learn more about rocketry first.

I will soon begin at my I-motor,just need the materials!

[varmit]

Ok,now I know a little more about rocketry.

I saw your film esa, a good film

 

I will post the film of my rocket launch +some photos I will take when I make the rocket

[esa]

Here is a little update...

 

I believe I have my final design plan for my rocket Pioneer, seen here:

 

Then the drag:

 

I have already started the building process, but it takes time..

Here is what the rocket will look like (in a way):

 

The half-done motor mount:

 

The hard black plastic chunk, which I'm going to turn on a lathe for the nosecone:

 

Example bulkheads, I need a size in between those two:

 

Then a quick sketch of what might be my deployment system:

 

I have already done testing/research on a lot of things so far (like parachutes, ejection charges, etc.) and even finding places where I could get ahold of these.

 

There will be more updates when I get farther into the construction

 

Oh, and I also found a good picture basically showing how a rocket works (just to help those who are new to rocketry)

 

esa

[varmit]

Wow, tell us when you are ready!

And we would be very happy for a film of the rocket

[omr]

Just a quickie, what material did you use for you casing and nozzle?

I have been looking into a Lead/Steel alloy ("Ledloy") for easier turning of the nozzle on my lathe.

[esa]

Just a quickie, what material did you use for you casing and nozzle?

I have been looking into a Lead/Steel alloy ("Ledloy") for easier turning of the nozzle on my lathe.

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I used 303 (300 something) stainless steel, for the casing/nozzle/bulkhead. Usually stainless steel is hard to turn on a lathe, but this big lathe I used had no problem. Plus the 303 (I believe) is the softest stainless steel, but normal steel should be easier to turn on a lathe. Whatever works best for you on the lathe, then just make a comparasion to the tensile strength (if there is any info on the steel your using). Run it through a motorcalc, and see the dimensions needed for the type of steel you are going to use. Richard Nakka has a good motorcalc for that I believe, so does Scott Fintel (but you now have to be a member to access his site). You can easily find the links to those pages in this topic...

 

With my project, I haven't really done much. Its been "on hold", but I've still done experiments with various chemicals, and even tested some "steam" rocket motors I have made. Also, I plan to do a failure test for a bent casing I have. In other words, I am planning to blow it up either confined in water or underground

 

esa