Is this website about hypersonics legitimate ? (EDIT: It's absolute fiction)

[sevenperforce]

57 minutes ago, FleshJeb said:

My dumb question of the day is: Is there a propulsive efficiency cost in the phase-change of the fuel from liquid to gas? I forget all my thermodynamics, and I am now frantically googling what "adiabatic" means.

Haha!!

It is much easier to pump a liquid than to pump a gas. So there's an advantage. Any decent high-efficiency rocket engine is going to use regenerative cooling at some level, which transfers waste heat to the propellant which makes the whole engine more efficient. There is usually going to be plenty of waste heat available to heat your propellant as warm as necessary. If he had 16,000 psi hydrogen at 0°C then it would get EXTREMELY cold if allowed to exhaust and expand to ambient...fairly certain it would self-liquefy.

He has very little information about his fancy rocket engine's closed-cycle mode, but if what he's proposing is simply a pressure-fed gas-gas rocket, then....I mean, yes, that would work. Exhaust the GH₂ and the GOX straight into the combustion chamber. Keep the chamber pressure high enough and it's fine. It's the propellant containment that's an issue.

Ullage might be an issue eventually though.

 

[mikegarrison]

1 hour ago, FleshJeb said:

I am now frantically googling what "adiabatic" means.

Adiabatic means there is no net flux of heat into or out of the system.

[JcoolTheShipbuilder]

2 hours ago, Spacescifi said:

With enough staging, one can launch ANYTHING...not tied down.

What about the planet?

[insert_name]

4 hours ago, sevenperforce said:

I feel like he has very odd ideas about the interplay between density, mass, and volume....

"Overall fuel capacity for Raven is beyond 18,000 gallons (which liquid fuel weight would be beyond 140,000lbs), which since it is designed to be fueled by hydrogen; and oxygen for orbital capabilities,  that reduces overall take off weight greater then 140,000 LBS."

Does...does he think that compressing hydrogen produces a higher energy density but not a higher volumetric density??

Not to mention that  measuring your capacity by volume is a waste of time with a heavily compressed gas like that

[Selective Genius]

@sevenperforceHis rocket nozzles are rectangular. Wont it cause flow separation and turbulence at the corners?

 

[Spacescifi]

49 minutes ago, Selective Genius said:

@sevenperforceHis rocket nozzles are rectangular. Wont it cause flow separation and turbulence at the corners?

 

 

Hmmm...Elite dangerous much?

 

Spoiler

 

 

And no...ED ships don't fly well in the air KSP. Let alone reach orbit on their own like SSTO's.

Edited April 16, 2021 by Spacescifi

[wumpus]

On 4/15/2021 at 2:04 PM, sevenperforce said:

That's probably even more mean but I won't say no

Only mean if you make them in RO.  Between KSP's low delta-v requirements (i.e. air breathing SSTOs will work) and general extremely heavy fuel tanks (to make up for the challenge), they might even make sense.  I hope he didn't get any of these ideas from KSP (presumably a short stint.  I'd expect more rocket science from a long term player).

Other things I noticed:

"Copyright 2018-2030 IO Aircraft | Drew Blair".  So while it might not be "20-30 years into the future", expect at least 10.  And one guy has been using CAD for 2 years (presumably got a ton done during the pandemic) without learning the rocket science of a KSP player.

I'm particularly amused by the use of an aerospike in the air-breathing SSTO design.  So you want an  engine that is wildly less efficient than your air-breathers in the atmosphere (and doesn't explain why you are using it) and also invariably less efficient than a bog-standard vacuum nozzle in vacuum.  But since these designs are all about being buzzword-compliant, I'm not surprised.

[cubinator]

15 hours ago, Selective Genius said:

His rocket nozzles are rectangular. Wont it cause flow separation and turbulence at the corners?

It's like a cross between a conventional nozzle and an aerospike in all the worst ways.

[sevenperforce]

41 minutes ago, wumpus said:

On 4/15/2021 at 2:04 PM, sevenperforce said:

That's probably even more mean but I won't say no

Only mean if you make them in RO. 

It's mean by calling more attention to it, I think