alpha tech

Making a rocket to beat all other rockets

274 posts in this topic

Posted (edited)

@alpha tech How big is the satellite you're planning on building? 

Keep in mind, dude, Earth is a lot bigger than Kerbin. 

In Low Kerbin Orbit, you're going at ~2,300 m/s. 

In Low Earth Orbit, it's ~8,000 m/s. 

So take a KSP rocket and scale up the Delta-V in it by that much. 

That should give you the Delta-V you need.

Edited by KAL 9000

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1 minute ago, KAL 9000 said:

@alpha tech How big is the satellite you're planning on building? 

Keep in mind, dude, Earth is a lot bigger than Kerbin. 

In Low Kerbin Orbit, you're going at ~2,300 m/s. 

In Low Earth Orbit, it's ~8,000 m/s. 

So take a KSP rocket and scale up the Delta-V in it by that much. 

That should give you the Delta-V you need.

That is why I need a very efficient first stage to de the heavy lifting and then a second stage to kick it near orbital velocity and a third stage to finalize it and I need to figure antenna to work this out for communication

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Posted (edited)

4 hours ago, alpha tech said:

I need one where I can test ideas on and a proto type

Static tests

4 hours ago, alpha tech said:

Also is not that I don't care about safety it's just that if it comes to my attention that something is dangerous I will take precautions

This is why documentation is needed. If something is dangerous but you don't know or think it is, you could be killed. You tell us what your going to do in depth then we would be able to point it out.

4 hours ago, alpha tech said:

And I also need a list of fuels that I could try and mix different than kno3 and sugar. 

I know this sounds rude it is NOT  supposed to.  You can do that yourself. Only use sources you find credible. Also, posting links to the research you have done is part of documentation.

21 hours ago, munlander1 said:

I also think you should join a rocketry forum

So have you made any progress here?

4 hours ago, alpha tech said:

if I bring the thrust chamber to a fine point and expand it for the gas will it produce a higher thrust

I think you are thinking of making a nozzle. One of the problems here is the exhaust velocity. You have to get it has close to the atmospheric pressure at that altitude. That is why in a vacuum the most efficient nozzle is an infinity large one. Since your rockets will be flying around normal atmospheric pressure, you will end up with a much shorter nozzle. Similar to the space shuttle's srb's.

4 hours ago, alpha tech said:

That is why I need a very efficient first stage to de the heavy lifting and then a second stage to kick it near orbital velocity and a third stage to finalize it and I need to figure antenna to work this out for communication

You are a long way from here. I would not worry about that stage right now at all.

Edited by munlander1
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i think I have a problem how can I get the rocket to go straight up without going off coarse too much cause I live near a lot of trees

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2 hours ago, alpha tech said:

i think I have a problem how can I get the rocket to go straight up without going off coarse too much cause I live near a lot of trees

Buy any rocket off this list and appropriate motors for the rocket. Please provide proof of purchase (receipt, the rocket, etc.). Once you buy one you don't have to get another launch stand (that is if you don't want another). They sell rockets without launch stands also. Follow the directions and local regulations before you launch.  

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This thread has to be a giant joke on everybody.

2 people like this

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OK I have a concept for finding how I need to make the rocket by calculating the volume and density of the fuel and the density of the container by the volume to get the mass of the stage and all I have to do to is repeat this and add the last stages mass and by the burn rate of propellant and mass to acommadate for stage. this is only a theroy I haven't figured it all out yet and I need an approximation of the Delta v I need to achieve this orbit.

  @munlander1

Your thoughts on this

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3 minutes ago, alpha tech said:

finding how I need to make the rocket

Can you explain this more?

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OK if I know my Delta v I came do approximations on how I need to build the stages of my rocket by calculating fuel mass burn rate etc

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2 minutes ago, alpha tech said:

OK if I know my Delta v I came do approximations on how I need to build the stages of my rocket by calculating fuel mass burn rate etc

You can't calculate delta v before you design your rocket. That's like finding a car's mpg before designing it.

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No the Delta v to get to orbit

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I can use that to get an ideal of how I need to separate the Delta v over 3 stages and then I build the rocket calculating the mass of the fuel and the volume needed to get the Delta v and the density/volume for the container for the fuel and the payload and all other parts that are unlisted.  And I can repeat this for all other stages but adding the mass of the previous stages

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Just now, alpha tech said:

I can use that to get an ideal of how I need to separate the Delta v over 3 stages and then I build the rocket calculating the mass of the fuel and the volume needed to get the Delta v and the density/volume for the container for the fuel and the payload and all other parts that are unlisted.  And I can repeat this for all other stages but adding the mass of the previous stages

Well, I mean I guess that could work but that is really only for orbital space flight. Right now, I don't think you should be worried about that.

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Just now, munlander1 said:

Well, I mean I guess that could work but that is really only for orbital space flight. Right now, I don't think you should be worried about that.

That's ok I can tone it down to work with smaller rockets

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Just now, alpha tech said:

That's ok I can tone it down to work with smaller rockets

So, you would have to have a specific dv in mind. You would also have to take drag and other forces into account.

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Posted (edited)

Delta v required to hit the edge of the atmosphere? And for drag and stuff just add more Delta v to last stage 100m/s maybe?

Edited by alpha tech

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Posted (edited)

9 minutes ago, alpha tech said:

Delta v required to hit the edge of the atmosphere?

1.4 km/s it looks like. You can google this stuff. Technically, you would be still in the atmosphere if you cross the karman line at 100km. But to do that, you would have to measure your motor in pounds. I think one rocket's motor was 16 pounds. That means lots of paper work.

Edited by munlander1

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1 minute ago, alpha tech said:

Delta v required to hit the edge of the atmosphere?

Delta-v needed for launch operations is highly dependent on your TWR.  If your have a TWR of 20, then you need a lot less d-v to get to the same height than if you have a TWR of 1.001, and if your TWR is < 1, you will not get anywhere.

You will also need to account for drag once you have got a TWR > 1, but I am not familiar enough with the math to know how much of an impact drag will have on your required d-v budget.(I just know that it is enough to justify fairings for everything that is not already reasonably aerodynamic)

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2 minutes ago, munlander1 said:

I have no idea. Technically, you would be still in the atmosphere if you cross the karman line at 100km. But to do that, you would have to measure your motor in pounds. I think one rocket's motor was 16 pounds. That means lots of paper work.

Well orbital velocity is about 17500 mph so I think the x15 went about 5000 MPH

2 minutes ago, Terwin said:

 

and it got into space where you could feel no gravity

 

4 minutes ago, Terwin said:

Delta-v needed for launch operations is highly dependent on your TWR.  If your have a TWR of 20, then you need a lot less d-v to get to the same height than if you have a TWR of 1.001, and if your TWR is < 1, you will not get anywhere.

You will also need to account for drag once you have got a TWR > 1, but I am not familiar enough with the math to know how much of an impact drag will have on your required d-v budget.(I just know that it is enough to justify fairings for everything that is not already reasonably aerodynamic)

I will take this Into consideration

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4 minutes ago, alpha tech said:

and it got into space where you could feel no gravity

If there was no gravity it would stay there.

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Just now, munlander1 said:

If there was no gravity it would stay there.

It was on suborbital trajectory but pilots experienced zero g

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1 minute ago, alpha tech said:

It was on suborbital trajectory but pilots experienced zero g

Well gravitational fire I defined by mass and distance. You are being pulled by everything in the universe.

 

But back to rockets! So when do you plan to buy the rockets?

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Whenever I get more money. 

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3 minutes ago, alpha tech said:

It was on suborbital trajectory but pilots experienced zero g

Well technically anything in freefall you're experiencing zero g. Hit a bump hard enough in a car and you'll experience zero g for a second.

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Just now, peadar1987 said:

Well technically anything in freefall you're experiencing zero g. Hit a bump hard enough in a car and you'll experience zero g for a second.

That is only at apogee and only for seconds though.

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