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Will a jet engine work?

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rAiN_Twist

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Hello guys,
New to this forum, so sorry if I put this in the wrong area. Anyways, most people are going to say this is implausible, but I want to try it anyways. To get a ~3 gram model rocket into space, theoretically you would need around 340 single use model rocket engines to make it to space (right outside the exosphere). But what if I were to make a jet engine, for a light weight rocket, it wouldn't be necessarily a model rocket. But instead of using a rocket engine, you take a jet engine up to 40,000 feet. Then switch to a oxygenator (or a jet engine) because above 40,000 feet oxygen is scarce. I read somewhere the reason NASA doesn't use jet engines, is because it wouldn't be able to lift the load of a spaceship, but if you were to make a light weight rocket. Would that work? Thanks in advance.


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dhbarr

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Tsiolkovsky
For 40k feet it's a lot easier and cheaper to use a commercial high power motor, for which you would need practice leading to certification.
 

rAiN_Twist

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For 40k feet it's a lot easier and cheaper to use a commercial high power motor, for which you would need practice leading to certification.
That's the problem though, I want it to go higher than 40k feet. It would just use the same principle as a jet engine until 40k feet, then it would use a oxygenator just like a jet engine. That's why it would have to be custom fabricated.


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tomsteve

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"theoretically you would need around 340 single use model rocket engines to make it to space (right outside the exosphere). "

what rocket motors are involved in this theory?
 

dhbarr

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That's the problem though, I want it to go higher than 40k feet. It would just use the same principle as a jet engine until 40k feet, then it would use a oxygenator just like a jet engine. That's why it would have to be custom fabricated.


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Sure, you're thinking of burning fuel and air to start with, gradually switching over to fuel & oxidizer. I think you may be radically underestimating the difficulty / cost of building a light enough engine, but don't let me stop you.

If all you want is to build a jet, there's forums dedicated to that sort of thing. If all you want is to hit a particular altitude, multi-stage rockets to significant height ( though neither simple nor inexpensive ) are routinely done here.

Start small, and work up to it :)
 

rAiN_Twist

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Sure, you're thinking of burning fuel and air to start with, gradually switching over to fuel & oxidizer. I think you may be radically underestimating the difficulty / cost of building a light enough engine, but don't let me stop you.

If all you want is to build a jet, there's forums dedicated to that sort of thing. If all you want is to hit a particular altitude, multi-stage rockets to significant height ( though neither simple nor inexpensive ) are routinely done here.

Start small, and work up to it :)
What are some ideas you have of getting a model rocket to space?


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rAiN_Twist

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"theoretically you would need around 340 single use model rocket engines to make it to space (right outside the exosphere). "

what rocket motors are involved in this theory?
C6-5 Estes rocket motors


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les

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So a C6-5 itself weighs 0.91oz.
340 engines will weigh 309.4 oz.
With a max lift off weight of 4 oz, according to Estes literature, 74 will have to ignite just to lift the weight of the engines.
But that does not include any structure to hold all the engines together or the next stage.
Maybe you have a super light structure, but you will still probably need a minimum of half of the engines for your first stage.
To keep the math simple, let's be generous and say you only needed 140 to burn for the first stage.
That leaves 200 left, or 182 oz of just engine weight. Again with a max of 4 oz liftoff weight this is 46 engines worth. But with rocket structure say 80 are needed
Down to 120 engines - 109.2 oz - 28 engines. Be generous - you've been dropping pieces so only 40 engines needed at this point
80 = 72.8 oz = 19 engines w/o structure or 30 more realistic
50 left - doubt you are even at 5000 feet yet (trying to relate to a Comanche 3)
.....
Bottom line - I don't see 340 C6-5 engines getting you space.........
 

rAiN_Twist

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So a C6-5 itself weighs 0.91oz.
340 engines will weigh 309.4 oz.
With a max lift off weight of 4 oz, according to Estes literature, 74 will have to ignite just to lift the weight of the engines.
But that does not include any structure to hold all the engines together or the next stage.
Maybe you have a super light structure, but you will still probably need a minimum of half of the engines for your first stage.
To keep the math simple, let's be generous and say you only needed 140 to burn for the first stage.
That leaves 200 left, or 182 oz of just engine weight. Again with a max of 4 oz liftoff weight this is 46 engines worth. But with rocket structure say 80 are needed
Down to 120 engines - 109.2 oz - 28 engines. Be generous - you've been dropping pieces so only 40 engines needed at this point
80 = 72.8 oz = 19 engines w/o structure or 30 more realistic
50 left - doubt you are even at 5000 feet yet (trying to relate to a Comanche 3)
.....
Bottom line - I don't see 340 C6-5 engines getting you space.........
True, I didn't really do the math. I was just saying theoretically it's not very practical. So I'm trying to find a alternative engine to get a model rocket to space (with a GoPro on it [emoji39])


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watermelonman

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You are not getting any objects to space without enormous effort, experience, and cost.

Start smaller and build up.
 

rAiN_Twist

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You are not getting any objects to space without enormous effort, experience, and cost.

Start smaller and build up.
But let's say I had the time and money. I don't want an answer "start small and build up". I want to know what kind of engines I would need to make a model rocket, or a little bigger rocket to space.


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DavidMcCann

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But let's say I had the time and money. I don't want an answer "start small and build up". I want to know what kind of engines I would need to make a model rocket, or a little bigger rocket to space.

That's the problem. You can not just jump into this with any amount of money and succeed. Money is needed, but it doesn't matter. Unless you have years of experience, knowledge, and and many many many things go right, you are not getting into space.

Countries have a hard time doing this. If you don't want the answer, don't ask the question. Because no one, anywhere is going to tell you "yep, it's simple to get into space, anyone can do it" There is a reason it's hard.

The first step to getting into space for you, is going to be admitting it's not easy and you have a long way and time to go.
 

rAiN_Twist

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That's the problem. You can not just jump into this with any amount of money and succeed. Money is needed, but it doesn't matter. Unless you have years of experience, knowledge, and and many many many things go right, you are not getting into space.

Countries have a hard time doing this. If you don't want the answer, don't ask the question. Because no one, anywhere is going to tell you "yep, it's simple to get into space, anyone can do it" There is a reason it's hard.

The first step to getting into space for you, is going to be admitting it's not easy and you have a long way and time to go.
Omg, I know, I have a long ways before I can reach space. I'm asking what type of engine it would take to get to space. And the different type of engines that would get a model rocket to space.


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matthewdlaudato

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Should I go get popcorn? That's it, I'm going to get a big bag of popcorn! 🍿
 

les

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So far the only non professional rocket to reach space used an S50,150 motor with 435lbs of propellant and costing $60,000.

http://www.ddeville.com/derek/CSXT.htm
Omg, I know, I have a long ways before I can reach space. I'm asking what type of engine it would take to get to space. And the different type of engines that would get a model rocket to space.


rAiN Twist - YouTube
Part of the problem I think is semantics. To us the term "model rocket" is typically used for low power rockets
Then there is high power rocketry.
You can't get a low power rocket into space, unless it gets hand carried up by an astronaut to the space station. You need a hi power rocket for that

Your question was answered for a high power rocket - it took an S 50150 motor that contained 435 pounds of propellant....
 

rAiN_Twist

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Part of the problem I think is semantics. To us the term "model rocket" is typically used for low power rockets
Then there is high power rocketry.
You can't get a low power rocket into space, unless it gets hand carried up by an astronaut to the space station. You need a hi power rocket for that

Your question was answered for a high power rocket - it took an S 50150 motor that contained 435 pounds of propellant....
So a S 50150 would theoretically take a small rocket to space?


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les

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define small.....
Relative to a low power rocket with C6-5 engines - no, it was huge!!
Compared to a Saturn V it was small

Their rocket was 10" in diameter, 21 feet tall, and weighed 724 pounds at liftoff (again, 435 pounds of that was propellant)
 

rAiN_Twist

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define small.....
Relative to a low power rocket with C6-5 engines - no, it was huge!!
Compared to a Saturn V it was small

Their rocket was 10" in diameter, 21 feet tall, and weighed 724 pounds at liftoff (again, 435 pounds of that was propellant)
Yeah, I just saw that when I looked up S 50150. That was definitely not as small as a model rocket. No, I'm asking, what motor would it take to shoot something about 3-5" in diameter, and about 3-5 foot tall into space.


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Flyfalcons

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Magic fairy farts should do it if you feed the fairys the right combo of chicken wings and cheese sticks.
 

noffie79

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Yeah, I just saw that when I looked up S 50150. That was definitely not as small as a model rocket. No, I'm asking, what motor would it take to shoot something about 3-5" in diameter, and about 3-5 foot tall into space.


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I'm pretty sure the consensus is that you can't get something 3-5" in diameter and about 3-5 feet tall into space...
 

rAiN_Twist

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I'm pretty sure the consensus is that you can't get something 3-5" in diameter and about 3-5 feet tall into space...
Those were just some random numbers a picked. But let's say this, something under 6 foot, and something under 8" in diameter.


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les

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Yeah, I just saw that when I looked up S 50150. That was definitely not as small as a model rocket. No, I'm asking, what motor would it take to shoot something about 3-5" in diameter, and about 3-5 foot tall into space.


rAiN Twist - YouTube
Magic fairy farts should do it if you feed the fairys the right combo of chicken wings and cheese sticks.
I'm pretty sure the consensus is that you can't get something 3-5" in diameter and about 3-5 feet tall into space...

Using our known propellants you can't launch something that small to fly on its own to space. You can't pack sufficient energy into something that small - except for possibly the magic fairy farts mixed with a sprinkle of pixie dust..... or Back to trying to get someone to carry it as luggage on a real rocket flight

Ooops - see you updated your numbers, but still too small

The rocket was as big as it was because it needed to be that big to make its flight. They were not going to waste weight by building it bigger than it needed to be
 
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rAiN_Twist

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I did the math, if I were to use G80 motors. To make it halfway to space, I would need 150 motors. There would be 8 stages, and it would be 20" in diameter, 6 foot tall, and 20 motors in each stage. Not only that, but it would have to be made out of a Pringles can. Mostly because they can only lift 32 oz. If each motor weighs 4.2 oz then you would need 20 motors on each stage to even lift all the rocket.


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bobkrech

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Hello guys,
New to this forum, so sorry if I put this in the wrong area. Anyways, most people are going to say this is implausible, but I want to try it anyways. To get a ~3 gram model rocket into space, theoretically you would need around 340 single use model rocket engines to make it to space (right outside the exosphere). But what if I were to make a jet engine, for a light weight rocket, it wouldn't be necessarily a model rocket. But instead of using a rocket engine, you take a jet engine up to 40,000 feet. Then switch to a oxygenator (or a jet engine) because above 40,000 feet oxygen is scarce. I read somewhere the reason NASA doesn't use jet engines, is because it wouldn't be able to lift the load of a spaceship, but if you were to make a light weight rocket. Would that work? Thanks in advance.


rAiN Twist - YouTube
The answer is that is not only implausible, but impossible, both theoretically and practically, to put a 3 gram model rocket into space with any number of SU hobby rocket motors. By definition a FAA Class 1 model rocket can not weigh more than 1500 grams loaded on the pad, and may not contain more than 125 grams of propellant. At most you can obtain ~270 Ns of total impulse, and your rocket's minimum weight will be ~500 grams if you made a very efficient 2 or 3-stage rocket using high specific impulse hobby rocket motors. I'm not going to optimize the rocket for you but you could probably achieve 3 km to 5 km apogee.

To get to space, >100 km, you need a Class 2 high power or Class 3 amateur rocket. I suggest you do some research on the sounding rockets developed in the 50's and 60's to see what is required. The long-burn Super Arcas and the and the fast-burn Loki Dart rockets represent the 2 design extremes that reached 100 km. Both rockets weigh well in excess of 10 kilograms and require a Class 2 high power motor at a minimum.

http://www.astronautix.com/s/superarcas.html and http://www.designation-systems.net/dusrm/n-12.html
 

les

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I did the math, if I were to use G80 motors. To make it halfway to space, I would need 150 motors. There would be 8 stages, and it would be 20" in diameter, 6 foot tall, and 20 motors in each stage. Not only that, but it would have to be made out of a Pringles can. Mostly because they can only lift 32 oz. If each motor weighs 4.2 oz then you would need 20 motors on each stage to even lift all the rocket.


rAiN Twist - YouTube
You also have to consider the strength required for your building materials. Between the G forces from the motors and the aerodynamic forces and heat from multiple mach speed your Pringles cans would collapse.
The Qu8k rocket body was made from aluminum, hit Mach 5 with 15G, and went to about 121,000' or just under 23 miles
I believe the GoFast was also aluminum and it also hit Mach 5 with 23G, and went to 72 miles and officially into space.

And as bobkrech pointed out, the propellant & rocket weights would exceed the legal definition of a "model rocket".

Interesting thoughts, but it can't be done - sorry
 
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