What Chemical Rocket Design has the Greatest Possible Thrust To Weight Ratio?

[Spacescifi]

I only ask because I was thinking of a linear acceleration scifi drive that relies on main rocket engine acceleration to start it, but after you shut the rocket engine down the scifi drive will continue accelerating in a linear manner at the same rate as the rocket engine was before it shut off.

 

The reason I wanted to know what the highest thrust to weight ratio of a chemical rocket was is because if I know that I can also know the maximum possible mass/weight an SSTO can be using chemical rocketry.

 

Obviously it needs enough thrust to get off the ground... but after that you can just turn on the scifi linear acceleration and let it do the rest as the SSTO takes off.

It's also great to use for 1g acceleration in space and great for ISRU rocket applications.

 

Thoughts?

 

Overall it is less overpowered thsn other ideas I have had but still utilizes rocketry that is not a fantasy torch or a radioactive nightmare.

 

Edited October 10, 2022 by Spacescifi

[mikegarrison]

Simple solid rockets probably have the best TWR.

Edited October 10, 2022 by mikegarrison

[Spacescifi]

1 hour ago, mikegarrison said:

Simple solid rockets probably have the best TWR.

 

Solid rockets are a no go because they are a pain to reuse. Also not something you easily throttle.

I wanted something you could reuse quickly.

 

EDIT: On second thought you may be on to something. Solid rockets can be throttled or turned on and off... so there is no reason to think such an engine could not exist.

 

And solids have better TWR than chemical rockets due to the fact that they have denser fuel so it requires less fuel to get the same amount of thrust you would get with a chemical rocket.

Edited October 10, 2022 by Spacescifi

[DDE]

Exteme TWR in LRPEs was mostly attempted through exotic, high-density propellants. At one point, some madman tried a mercury compound.

[kerbiloid]

Why need the extremely high thrust at all?

Probably, it's a continuation of the former idea from thie forum of Sprints as space rockets.

[Shpaget]

Why does it matter at all? If you have such a magical drive, just accelerate the drive (not the whole ship) on some short rails.

A hammer would do.

[Spacescifi]

6 hours ago, kerbiloid said:

Why need the extremely high thrust at all?

Probably, it's a continuation of the former idea from thie forum of Sprints as space rockets.

 

To lift the heaviest SSTO possible off the ground and then turn on the scifi constant linear acceleration drive to duplicate the rocket's thrust after shutting down the rocket.

 

The more thrust the heavier SSTOs you can manage.

 

Basically maybe it is possible to get 8000 ton SSTOs... perhaps with ten percent being fuel/propellant.

5 minutes ago, Shpaget said:

Why does it matter at all? If you have such a magical drive, just accelerate the drive (not the whole ship) on some short rails.

A hammer would do.

A hammer thrown out the back won't generate the TWR to launch a multi-kiloton SSTO.

[wumpus]

13 hours ago, Spacescifi said:

 

Solid rockets are a no go because they are a pain to reuse. Also not something you easily throttle.

I wanted something you could reuse quickly.

EDIT: On second thought you may be on to something. Solid rockets can be throttled or turned on and off... so there is no reason to think such an engine could not exist.

And solids have better TWR than chemical rockets due to the fact that they have denser fuel so it requires less fuel to get the same amount of thrust you would get with a chemical rocket.

 

2 hours ago, Spacescifi said:

To lift the heaviest SSTO possible off the ground and then turn on the scifi constant linear acceleration drive to duplicate the rocket's thrust after shutting down the rocket.

The more thrust the heavier SSTOs you can manage.

Basically maybe it is possible to get 8000 ton SSTOs... perhaps with ten percent being fuel/propellant.

A hammer thrown out the back won't generate the TWR to launch a multi-kiloton SSTO.

Why ask about real fuel when none of them will work?

You want thrust?  Solids provide thrust.

Also note that SRBs can provide a certain amount of "pre-programmed thrust profiles" that closely resemble throttling.  The Shuttle did this and reduced thrust near maxQ.

But as long as you keep talking about SSTO, it doesn't matter what the thrust is: no known fuel makes any sense (with the possible exception of hydrogen + atmospheric oxygen).  You could have all the TWR in the world and you won't get to orbit in one stage.  I think some Japanese orbital rockets lifted off with TWR ~10, but used something like 5-7 stages to get to space.

[Shpaget]

3 hours ago, Spacescifi said:

A hammer thrown out the back won't generate the TWR to launch a multi-kiloton SSTO.

You don't throw the hammer, you use it to whack the drive with it. Then use the acceleration of vibration to magic the rest.

[farmerben]

An aerospike engine is best, otherwise the nozzle will not be optimum at some altitudes.

[MatterBeam]

A flat disk.
A layer of explosives.
... stacked

TWR should be in the millions.

[magnemoe]

16 hours ago, DDE said:

Exteme TWR in LRPEs was mostly attempted through exotic, high-density propellants. At one point, some madman tried a mercury compound.

This, and its only relevant for missiles, the common rocket propelled grenade has an rocket who burn out before leaving the launcher. 

For an orbital rocket TWR of engine is much less important, its a lot like an car, yes having an lightweight and powerful engine is nice but as the engine is just an fraction of the car's weight.
Efficiency is more important for an long run

[sevenperforce]

On 10/9/2022 at 10:04 PM, Spacescifi said:

I was thinking of a linear acceleration scifi drive that relies on main rocket engine acceleration to start it, but after you shut the rocket engine down the scifi drive will continue accelerating in a linear manner at the same rate as the rocket engine was before it shut off.

Obviously it needs enough thrust to get off the ground... but after that you can just turn on the scifi linear acceleration and let it do the rest as the SSTO takes off.

So, magic.

The answer, FWIW, is that you can give a chemical rocket engine almost arbitrarily high T/W.

A Merlin 1D at full thrust pushes a T/W ratio of around 180 which is certainly more than you'd need for any conceivable application.

On 10/9/2022 at 10:04 PM, Spacescifi said:

Overall it is less overpowered thsn other ideas I have had but still utilizes rocketry that is not a fantasy torch or a radioactive nightmare.

It's actually one of the most overpowered possible designs. It will be a relativistic projectile within a few hours.

On 10/9/2022 at 11:06 PM, Spacescifi said:

Solid rockets can be throttled or turned on and off... so there is no reason to think such an engine could not exist.

And solids have better TWR than chemical rockets due to the fact that they have denser fuel so it requires less fuel to get the same amount of thrust you would get with a chemical rocket.

Solid-propellant rockets are chemical rockets.

17 hours ago, MatterBeam said:

A flat disk.
A layer of explosives.
... stacked

TWR should be in the millions.

Yep, this should work.

You can have explosives in a semiliquid form that are pumped into a very wide cylindrical chamber, then have the doors open. Ignite it as you switch the linear accelerator on. T/W ratio is arbitrarily high.

[wumpus]

3 hours ago, sevenperforce said:

So, magic.

The answer, FWIW, is that you can give a chemical rocket engine almost arbitrarily high T/W.

A Merlin 1D at full thrust pushes a T/W ratio of around 180 which is certainly more than you'd need for any conceivable application.

It's actually one of the most overpowered possible designs. It will be a relativistic projectile within a few hours.

Solid-propellant rockets are chemical rockets.

Yep, this should work.

You can have explosives in a semiliquid form that are pumped into a very wide cylindrical chamber, then have the doors open. Ignite it as you switch the linear accelerator on. T/W ratio is arbitrarily high.

Are dilithium crystals trademarked?  If not, use them.  You don't want anything that would actually work (we've had this argument 100 times) so just use dilithium crystals.

[sevenperforce]

6 minutes ago, wumpus said:

Are dilithium crystals trademarked?  If not, use them.  You don't want anything that would actually work (we've had this argument 100 times) so just use dilithium crystals.

Dilithium crystals don't provide enough lithiums to counteract flux capacitor depression.

The only true solution is the trilithium crystal. 50% more lithium and 100% as much crystal.

 

[kerbiloid]

Spoiler