A lot of worlds over 1g gravity. How do 1G thrust ships take off?

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AnotherDilbert
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby AnotherDilbert » Sat Feb 09, 2019 8:52 pm

I watched a YT video with the F-15 pilot that survived. Apparently his arms and legs were almost ripped off when he was ejected into the airstream. One arm and both legs were severely broken, despite the ejection seat.

Perhaps we can count survival as a marginal possibility, but better than nothing.
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby phavoc » Sun Feb 10, 2019 5:44 pm

AnotherDilbert wrote:
Sat Feb 09, 2019 8:52 pm
I watched a YT video with the F-15 pilot that survived. Apparently his arms and legs were almost ripped off when he was ejected into the airstream. One arm and both legs were severely broken, despite the ejection seat.

Perhaps we can count survival as a marginal possibility, but better than nothing.
Captain Udell was only in a flight suit. The pilot, Bill Weaver, who survived when his SR-71 disintegrated around him and he was ejected was in a space suit. The extra protection he had made the difference. So unless the person was properly protected, yeah, ejecting at supersonic speeds is pretty much a death sentence. Udell's injuries probably should have killed him (and usually do). He got lucky.

If anyone is interested to read the story of the SR-71 pilot, you can find it here - http://www.chuckyeager.org/news/sr-71-d ... ived-tell/

In both cases the pilots survived and the other crewman perished.
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby nats » Mon Feb 11, 2019 9:53 pm

So have we established whether ships with 1G M-Drives could take off from a world with 1G of gravity at its surface? Do they use antigrav drives to get into orbit? I am sure I've read something like that, it's the only thing that seems to make sense to me.
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby Condottiere » Mon Feb 11, 2019 10:46 pm

Any form of anti gravity propulsion takes up space and costs money; you'd have to declare it on the design sheet.

Repurposing the manoeuvre drive to fulfill this function, if inefficiently and clumsily, then makes sense, the question would be how inefficient and how clumsy, one of which requires enough energy and diverted thrust, and the other if you need to make continuous piloting checks.
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby phavoc » Tue Feb 12, 2019 4:26 am

nats wrote:
Mon Feb 11, 2019 9:53 pm
So have we established whether ships with 1G M-Drives could take off from a world with 1G of gravity at its surface? Do they use antigrav drives to get into orbit? I am sure I've read something like that, it's the only thing that seems to make sense to me.
Well, that answer is probably still being debated. It was shown that MGT materials from Pirates of Drinax called for the ship to have grav plates (whatever that is supposed to mean) to take off from world's. The ship has a 1G drive and can take off from a 1.4G world without wings.

You'd have to read the very long thread and establish your own opinion. I'm rather biased towards one view and it's only fair that each person determine it for their self.
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby Condottiere » Tue Feb 12, 2019 7:10 am

Etra power could be drawn from batteries, assuming they're installed, though you can easily just take half of basic energy and reroute it to the manoeuvre drive without effecting the rest of the ship's systems, which coincidentally at ten percent is exactly what you'd need for an extra gee in thrust for a default manoeuvre drive.

If in six minutes you can gain enough altitude where one gee acceleration is sufficient for escape velocity, the engineer can concentrate totally on squeezing that extra factor in thrust from the propulsors.
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby phavoc » Tue Feb 12, 2019 2:11 pm

Condottiere wrote:
Tue Feb 12, 2019 7:10 am
Etra power could be drawn from batteries, assuming they're installed, though you can easily just take half of basic energy and reroute it to the manoeuvre drive without effecting the rest of the ship's systems, which coincidentally at ten percent is exactly what you'd need for an extra gee in thrust for a default manoeuvre drive.

If in six minutes you can gain enough altitude where one gee acceleration is sufficient for escape velocity, the engineer can concentrate totally on squeezing that extra factor in thrust from the propulsors.
I don't quite understand that. How can you take 50% of the ships "basic systems" power without affecting half the systems? And how is 10% (where are you getting that number from anyways?) going to get you an extra G worth of thrust?

As far as the batteries go, did you just advocate against antigrav lifters being included as part of the base hull cost because it costs money and takes up space, therefore it needs to be declared on the design sheet?
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby Condottiere » Tue Feb 12, 2019 3:14 pm

Basic ship systems energy requirement is twenty percent of volume, but you can getaway with ten percent before the lights start dimming and the gravity fluctuates, which kinda reminds me of jumping.

Even if you manage to overdrive the thrusters, you're going to need that extra energy from somewhere, so if as it's usual for commercial ships, that the defaut is manoeuvre drive plus basic systems, that extra ten percent has to be rerouted from basic systems.

Unless you have batteries installed, that at ten energy points per quarter tonne at twenty five thousand bucks, per hundred tonne displacement, is hilariously cheap compared to default early fusion reactor at a tonne and half a million quid (though granted, for batteries that's for a single six minute turn, and for the reactor that's ten energy points continuous).
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby Condottiere » Tue Feb 12, 2019 4:38 pm

Speaking of ejection seats:


Why Aborting From Gemini Would've Likely Killed The Crew

Climbing on top of a rocket is still nutty when you think about it. I mean you’re literally riding on top of a controlled explosion, sitting upon a column of flames until the blue sky turns black.

And because of the risky nature, it’s generally considered a good idea to have a backup in case things go wrong. Welcome to launch abort systems. Most human rated vehicles have some system to get people away from a failing rocket in a hurry, typically by pulling the crew capsule off of the rocket with a special set of abort motors.

But did you know that the United States’ second crew capsule, the Gemini spacecraft had an interesting solution for getting crew away from impending doom, an ejection seat… Today we’re going to take a look at an engineering solution to a problem that in hindsight would’ve almost certainly led to death... oh, and there’s much more to it than just the ejection seat that could’ve killed you, that’s only part of the equation…

https://www.youtube.com/watch?v=5IRdZjjq1Ik
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby Moppy » Tue Feb 12, 2019 5:00 pm

Still waiting for helicopter ejection seats.
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby Sigtrygg » Tue Feb 12, 2019 6:45 pm

Sideways and then up...
phavoc
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby phavoc » Tue Feb 12, 2019 7:16 pm

Sideways seems a much better option than up. Unless you blow the rotors first. Real men don't need autorotation!
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby Old School » Tue Feb 12, 2019 9:58 pm

nats wrote:
Mon Feb 11, 2019 9:53 pm
So have we established whether ships with 1G M-Drives could take off from a world with 1G of gravity at its surface? Do they use antigrav drives to get into orbit.
Yes, we established that. :D
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby AnotherDilbert » Tue Feb 12, 2019 10:47 pm

Old School wrote:
nats wrote: So have we established whether ships with 1G M-Drives could take off from a world with 1G of gravity at its surface? Do they use antigrav drives to get into orbit.
Yes, we established that. :D
We have established that some believe so, yes. Others disagree...
phavoc
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby phavoc » Wed Feb 13, 2019 12:50 am

AnotherDilbert wrote:
Tue Feb 12, 2019 10:47 pm
Old School wrote:
nats wrote: So have we established whether ships with 1G M-Drives could take off from a world with 1G of gravity at its surface? Do they use antigrav drives to get into orbit.
Yes, we established that. :D
We have established that some believe so, yes. Others disagree...
I agree with both of you. :lol:
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby Condottiere » Thu Feb 14, 2019 7:42 pm

If this were a movie, the issue would be described as a plothole.

As I always point out, I'm not an engineer, but my intuition tells me that if your drive factor is cancelled out by the local gravity, you can't reach escape velocity.

The funny thing is, the understanding of gravity and it's manipulation is the centrifugal Force that holds the Traveller universe together, whether allowing the creation of fusion bottles, anti gravity and probably the capability to punch holes through to another dimension.

I think it's the editorial policy of Mongoose neither to discuss nor explain how the negation and manipulation of gravity is carried out, which is why it's likely authors don't understand the ramifications of permitting factor one spaceships to take off from Earth sized planets.

I could be wrong, but it seems disingenuous not explaining the principles behind manoeuvre drives and vehicle anti gravity.

I feel the question is if the manipulation is a field effect, or what I'll describe as kinetics.

If the manoevre drive creates a field effect, then you could shape it so that the spaceship could vertcally land and take off, though I suspect factor one isn't sufficient beyond a certain altitude, maybe ten metres.

If the manoeuvre drive is just pure thrust, than the engines need to physically reorientated, or at best, the spaceship is a tailsitter.

Current rockets have to obtain an optimal amount of thrust in takeoff as a matter of fuel conservation, not something a spaceship with a fusion power plant and a manoeuvre drive have to worry about.

Even if a manoeuvre drive based spaceship blasted straight up, it supposedly has inertial compensation to elimate gee forces, and a local gravity field that orientates the crew to the established floor of the spaceship. Granted, that the planet's own gravity might counteract that to a forty five degree angle, it's also possible more sophisticated artificial gravity plating would compensate for that as well.
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby Sigtrygg » Thu Feb 14, 2019 7:49 pm

There is no such thing as centrifugal force...

:)
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby Moppy » Thu Feb 14, 2019 7:52 pm

Found out the Russian Black Shark helicopter gunships have ejection seats (as do the 2-seat variants). They blow the blades off first. I don't know how they end up controlling where the blades go after they get ejected but they claim it works. Then again, they claimed the machines worked in the desert too, and that having only a single crew member was OK, until Egypt bought a bunch and found out they don't work in the desert and that you need 2 crew.
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby phavoc » Thu Feb 14, 2019 8:24 pm

Condottiere wrote:
Thu Feb 14, 2019 7:42 pm
If this were a movie, the issue would be described as a plothole.

As I always point out, I'm not an engineer, but my intuition tells me that if your drive factor is cancelled out by the local gravity, you can't reach escape velocity.

The funny thing is, the understanding of gravity and it's manipulation is the centrifugal Force that holds the Traveller universe together, whether allowing the creation of fusion bottles, anti gravity and probably the capability to punch holes through to another dimension.

I think it's the editorial policy of Mongoose neither to discuss nor explain how the negation and manipulation of gravity is carried out, which is why it's likely authors don't understand the ramifications of permitting factor one spaceships to take off from Earth sized planets.

I could be wrong, but it seems disingenuous not explaining the principles behind manoeuvre drives and vehicle anti gravity.

I feel the question is if the manipulation is a field effect, or what I'll describe as kinetics.

If the manoevre drive creates a field effect, then you could shape it so that the spaceship could vertcally land and take off, though I suspect factor one isn't sufficient beyond a certain altitude, maybe ten metres.

If the manoeuvre drive is just pure thrust, than the engines need to physically reorientated, or at best, the spaceship is a tailsitter.

Current rockets have to obtain an optimal amount of thrust in takeoff as a matter of fuel conservation, not something a spaceship with a fusion power plant and a manoeuvre drive have to worry about.

Even if a manoeuvre drive based spaceship blasted straight up, it supposedly has inertial compensation to elimate gee forces, and a local gravity field that orientates the crew to the established floor of the spaceship. Granted, that the planet's own gravity might counteract that to a forty five degree angle, it's also possible more sophisticated artificial gravity plating would compensate for that as well.
We know, by inference at least, that internal inertial compensators and grav plates for flooring have a range of capabilities. Otherwise all these ships hopped up on reaction drive thrusters would squish their human cargoes. As you have pointed out, the rules are pretty vague in this area, thus discussions like this continue to crop up.

I personally don't think it's a good idea to have to depend on other versions of the game to illustrate how things work. We already know each publisher changes things for their particular versions, and what is canon in one can be non-canon in the next. Thus it makes sense to stick with the same version and let it stand or fall on it's own.

If you can control local gravity you can spin the ship on it's axis and the people inside will never know or feel it. If you can use antigrav to counteract the local gravity then you can fit it into places that are described in the books. And you can easily take off and land in more than 1G environments.
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Re: A lot of worlds over 1g gravity. How do 1G thrust ships take off?

Postby baithammer » Fri Feb 15, 2019 12:30 pm

Moppy wrote:
Thu Feb 14, 2019 7:52 pm
Found out the Russian Black Shark helicopter gunships have ejection seats (as do the 2-seat variants). They blow the blades off first. I don't know how they end up controlling where the blades go after they get ejected but they claim it works. Then again, they claimed the machines worked in the desert too, and that having only a single crew member was OK, until Egypt bought a bunch and found out they don't work in the desert and that you need 2 crew.
Blades are blown horizontally away from the hub, giving enough time for the most part to allow for ejection.

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