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HLHL Versus VLVL


Spacescifi
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I am referringto horizontal launch/landing versus all vertical ones with spaceflight.

 

It seems going either all vertical or all horizontal is the best approach for either.

 

Thoughts: VLVL can work anywhere, whereas HLHL does not work so well in places with low atmosphere since often HLHL relies on wing interaction to glide or guide to a safe landing.

The main advantage of HLHL is easier egress of cargo and personal before launch.... something one may want with a mature future regular manned presence in space, but not now.

Now what do you know?

Edited by Spacescifi
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34 minutes ago, Spacescifi said:

since often HLHL relies on wing interaction to glide or guide to a safe landing.

So you mix two very different dichotomies: aerodynamic lift vs all-rocket propulsion at landing, and tailsitters vs bellylanders. Thus your proposed dichotomy is false.

Spoiler

2706.jpg

01-Phoenix.jpg

The major disadvantage of a no-atmo HTHL, the need for two engines, can be further obviated once space assembly/significant reassembly becomes available: you can always fly like that:

scale_1200

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Horizontal landing require an runway who is another restriction. That is unless its landing under trust who is possible but require separate landing engines. think of an starship who did not turn upright but landed horizontal on four landing engines. This can also be done in vacuum, a bit like moonship landing but you flip it 90 degree before touchdown or an way to land planes on the Mun in KSP. 
None of this is very practical with current technology. 

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The biggest issue with horizontal takeoff for  atmospheric flight to space  is getting that huge mass of fuel/propellants  up to speed, never mind stopping it if the takeoff is aborted. It would require massive landing gear or a ground-based takeoff carriage. 

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3 hours ago, DDE said:

So you mix two very different dichotomies: aerodynamic lift vs all-rocket propulsion at landing, and tailsitters vs bellylanders. Thus your proposed dichotomy is false.

  Reveal hidden contents

2706.jpg

01-Phoenix.jpg

The major disadvantage of a no-atmo HTHL, the need for two engines, can be further obviated once space assembly/significant reassembly becomes available: you can always fly like that:

scale_1200

 

You are referring not to HLHL, but VLHL.

I do agree on low grav airless worlds that VLHL is very much possible and practical.

On Earth or similar though... or going to an Earth analogue, it would seem you are better off, for the sake of simplified engineering and less possible points of complexity that can fail... to use wholly either HLVL or VLVL.

 

For HLHL  ramps are a possibility to reduce runway size, just burn for a some seconds, let inertia take the HLHL vehicle up the ramp till it is vertical and burn upward into the sky.

Landing would involve standard gliding and runways or could involve the ocean if an amphibous vehicle.

 

VLVL is something Elon has well covered though I think... unless anyone has anything to add to it who is not Bezos...

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1 hour ago, Spacescifi said:

You are referring not to HLHL, but VLHL.

The terminology is wholly inappropriate. This thing

01-Phoenix.jpg

can be called a VTVL because of the manner it moves in, or a HLHL because of its orientation throughout said processes. Either way, it satsy V or H in both modes. Sort out the semantics before any further discussion; we're talking past each other.

Aircraft-style horizontal landing on airless worlds (i.e. lithobraking against the runway) seems too ridiculous to wrap my head around. Because of that, it seems you use "horizontal landing" to refer to two absolutely different manners of takeoff and landing depending on whether the world is airless or not.

1 hour ago, Spacescifi said:

For HLHL  ramps are a possibility to reduce runway size, just burn for a some seconds, let inertia take the HLHL vehicle up the ramp till it is vertical and burn upward into the sky.

Are we still talking about airless worlds? Ramps are an unnecessary wastage of dV when you can just climb upwards.

Edited by DDE
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8 hours ago, JoeSchmuckatelli said:

latest?cb=20120101144521

 

If I recall, this worked.

(but as to what you write above: I think you've asked and answered your own question)

We need a 'not within current capabilities' ship to do HLHL effectively

IIRC, this crashed and left them on a planet full of monsters.

And also was just a movie prop.

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only real reason to go with hthl is that the earth has more airports than spaceports.  though with vehicles like skylon you would need to add lh2+lox fuel capabilities at those airports. you can also move skylon under its own power to any airport in the world for specific orbits and have it rendezvous with a tanker truck to re-fuel it for orbital insertion (if the airport lacks cryofuel capabilities). then you can land anywhere (runway length permitting) in case of emergencies or returns from weird orbits. i think a better way to use skylon is in a suborbital flight that puts the payload at a good fraction of orbital velocity and above the karman line, then open the payload doors and launch a second stage. they would be wise to design it with additional removable tankage such that they can easily reconfigure the vehicle to be a suborbital first stage with a larger payload bay to accommodate a bigger second stage and payload, or just have a suborbital model. reusable rockets are nice but without more facilities to handle them, i think the horizontal option give you the most versatility. space planes also come with practical military applications, for when you need to launch a spacecraft now, instead of when a launch window occurs. 

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8 hours ago, DDE said:

can be called a VTVL because of the manner it moves in, or a HLHL because of its orientation throughout said processes

It can't run along the runway, so it's a pure VTVL.

6 hours ago, mikegarrison said:

this crashed and left them on a planet full of monsters.

Just because they didn't close the cabin door, violating the pilot instructions.

Btw those rocket batteries were designed for LHX/Commanche, too. Just to be extended sideways, not up.

Edited by kerbiloid
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On 9/23/2021 at 5:29 PM, JoeSchmuckatelli said:

Failure to check out the aircraft prior to the flight = Pilot Error.

Result?

Internal FOD. 

 

 

i dont think xenomorph removal was on the checklist.

also aliens was kind of a commentary on the vietnam war. that decision making was so far removed from the action that it was impossible to give good instructions to troops in the field. that scene when the liutennant is in the apc and the aliens start coming out of the walls, all hell is breaking loose, and almost the entire squad gets wiped out while the commander hesitates to give viable orders. yea that happened in nam a lot, except replace aliens for charlie. 

Edited by Nuke
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2 hours ago, Nuke said:

i dont think xenomorph removal was on the checklist.

Unplanned passengers are.

And animals, too, even the sapient ones.

They haven't examined the cargo bay if everything is attached properly.

Also it's strange that the gear automatics hadn't signalized about the object stuck inside.

So, they haven't checked the systems before the launch from Sulaco.

Edited by kerbiloid
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i think they checked the systems at the sulaco. its the hot dustoff they didnt check. when i really think about it the alien got on twice. the one that took out the first drop ship, and the queen at the end. there is probibly something wrong with the ship's sensors.  not designed for xenomorphs. i still think its more of a case of bad intel than a failure of the pilot or the procedures. because even the synthetic bishop made the same mistakes, even with the fore knowledge that xenomorphs are sneaky. 

after seeing the intro to alien 3 i think they would have been better off remote launching the nukes. 

Edited by Nuke
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3 hours ago, Nuke said:

i think they would have been better off remote launching the nukes

You referred to the criticism of remote control of tactical decision making - but you are forgetting who the real 'bad guy' of the series is... 

Hint: it's not the Xenomorph 

 

 

 

 

 

 

 

(corporations, maaan... They're EVIL

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25 minutes ago, JoeSchmuckatelli said:

You referred to the criticism of remote control of tactical decision making - but you are forgetting who the real 'bad guy' of the series is... 

Hint: it's not the Xenomorph

We never asked Bishop if he'd let it on board, did we?

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46 minutes ago, JoeSchmuckatelli said:

who the real 'bad guy' of the series is... 

"Series"...

Five different directors with completely different visions of the movie and its ideology...

It's not a series, it's a network.

A1 = "spiritual horror", A2 = "psychological action", A3 = "chamber horror and psychological action", A4= "totally apocalyptica nightmare".

And the author of the A1 hates other movies of the "series" and considers them as heresy and blasphemy.
While other filmed their heresies before the Prometheus and Prometheus-2.

And everyone considers as heresy and blasphemy A3 and A4.

And let alone two A-vs-P.

But the main antagonist of all of them is Weyland-Yutani Corp. Just in every subseries its background varies.
(That's probably the only common place of all three Alien settings, except Ripley).

***

But @DDE is right.
If there are bad androids (badroids?) in every other episode but A2, why should that nice and smiling guy be not as bad as others (a goodroid)?

In A3 and A4 Ripley was infected while sleeping.
Who did that? Newt and Gorman (after A2) were sleeping. Jonsey (after A1) was sleeping together with Ripley.
Of course, Bishop was splitted in halves, but who says he needs both of them to crawl?

***

Btw, couldn't Jonsey be a W-Y catroid, managing Ash?

***

Back to the topic: A1, A2, P1, P2, AvsP all use VTVL landers.

Edited by kerbiloid
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One thing included in KSP (but not the demos. At least I don't think the pre-beta demo had it) is the ability to simulate aircraft.  HLHL gives you the joy of balancing Center of Mass/Center of Lift for combined stage takeoff, upper stage takeoff, and lower stage takeoff.  While I have no reason to believe this is impossible, it is quite difficult and will leave you with some tough choices and limitations.

The only advantage horizontal takeoff has is that you get a "free g" of acceleration while in horizontal flight.  On the other hand, you get to fight through the atmosphere at its thickest.  I'd assume this would be using some sort of air breathing engines, or possibly a rail system that accelerates the ship (likely to the point SCRAMJETs work).  I'd have to believe that any belief in less damage to the launch site is overrated: repairing several km of no longer smooth runway is far different than any effect  inside the firepit of a rocket launch site (I doubt they  care what happens to it).

I'd assume the advantages of horizontal landing are all about safety.  And here you are more or less assuming that all the loading (and CoM checks) are always safe, and that enough (you would have extra) engines coming down might fail to fire.  With current tech, there is a huge mass advantage for retro-rockets.  Any advance (especially magic that gives you SSTO) will keep tipping the balance to retrorockets.  And remember, mass is everything in rocket science.

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1 hour ago, kerbiloid said:

all use VTVL landers

Well... They're kind of both; they don't need a runway to get up to or bleed off speed - so yeah, launch and landing are initially VTVL... But they also (apparently) have atmospheric flight capability (as neophytes would describe 'flight '). 

They're clearly not 'rockets' in the sense of streamlined 'go up and over as fast as you can' or 'fall with style until you flip and power to a stop' like SS is intended.  But they do have the luxurious capability of being 'plane-like' once landed. 

I think that's what the OP wants (heck what we all want) - something with the convenience of a plane and the ability to drive it to the moon whenever we want to.  Runways are not required - in fact the ability to park it in the back yard is a plus! 

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10 hours ago, kerbiloid said:

"Series"...

Five different directors with completely different visions of the movie and its ideology...

It's not a series, it's a network.

A1 = "spiritual horror", A2 = "psychological action", A3 = "chamber horror and psychological action", A4= "totally apocalyptica nightmare".

And the author of the A1 hates other movies of the "series" and considers them as heresy and blasphemy.
While other filmed their heresies before the Prometheus and Prometheus-2.

And everyone considers as heresy and blasphemy A3 and A4.

And let alone two A-vs-P.

But the main antagonist of all of them is Weyland-Yutani Corp. Just in every subseries its background varies.
(That's probably the only common place of all three Alien settings, except Ripley).

***

But @DDE is right.
If there are bad androids (badroids?) in every other episode but A2, why should that nice and smiling guy be not as bad as others (a goodroid)?

In A3 and A4 Ripley was infected while sleeping.
Who did that? Newt and Gorman (after A2) were sleeping. Jonsey (after A1) was sleeping together with Ripley.
Of course, Bishop was splitted in halves, but who says he needs both of them to crawl?

***

Btw, couldn't Jonsey be a W-Y catroid, managing Ash?

***

Back to the topic: A1, A2, P1, P2, AvsP all use VTVL landers.

i think the real reason i didnt like alien 3 was the horrible special effects and not the fact that it killed everyone from the previous movie. the new compositing techniques made the alien look like a cartoon. the previous incarnations of aliens used practical puppetry and a lot of slime. even the guy in the suit from the first alien movie looked better, and that came out in '79. later movies with cgi xenomorphs also lost something in translation, but they were acceptable where as alien 3 really botched it entirely (which is a shame because the overall story and characters were great). 

Edited by Nuke
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I’m going to assume VTVL means entirely rocket propelled landings where the horizontal velocity is close to zero as for pretty much every rocket powered landing system ever (Falcon 9, LEM, Thunderbird 3…), and HTHL means horizontal velocity is very high compared to vertical velocity as for pretty much every plane ever.

Horizontal landing has obvious advantages where the atmosphere is thick enough to sustain aerodynamic flight, you can control your rate of descent without expending significant quantities of fuel fighting gravity as the wings do that for you. Air can also be used to get thrust, whether that’s with air breathing engines in an atmosphere with oxygen or using atmosphere as propellant for a nuclear engine without (see Project Pluto) which means less propellant to carry around and so more delta-V. An aircraft design also means it’s easier to load and unload cargo as the holds and cabins are nearer to the ground and would tend to be arranged horizontally on one level rather than stacked vertically in something like Starship.

Vertical landing is better where there’s no air- while you could try a runway landing in vacuum, the main advantages are lost and you’d have to try and balance the asymmetrical friction from the ground to prevent the whole craft from planting its nose and cartwheeling as well as needing retro-rockets to slow down (unless you wanted to land backwards, which sounds even worse!). Vertical landings are also better where precision is needed or where horizontal approaches are impractical, such as inside a crater or where there’s not enough open space for a runway.

On Mars, where the air is barely thick enough to generate usable lift, a hybrid approach would work best with aerodynamic lift bringing the craft low and slow enough to make a propulsive landing, a bit like those shuttles in Avatar. This gives the benefits of a horizontal approach (saving propellant) and a vertical landing (precision) and the lower the gravity the more attractive a vertical landing becomes as gravity losses are lower.

For getting off the ground, things are rather different- short of an air or atmosphere breathing engine to power your aircraft through the lower atmosphere, vertical takeoff rockets are better as they clear the thick atmosphere much faster to minimise efficiency losses via drag and lower engine performance. Where there’s no atmosphere, however, it’s more effective to make the most aggressive gravity turn possible as close to horizontal as possible without hitting the ground, to get up to orbital velocity with minimal gravity losses- plus there are options like electromagnetic accelerators (railguns and the like) which can provide a hefty impulse to smaller unscrewed vessels to throw them up to orbital velocity (or close to it) without using any propellant at all, or give a useful boost to a larger and/or crewed craft without crushing them with the G forces; these wouldn’t work nearly as well with an atmosphere present due to friction heating and drag losses.

 

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