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

[AnotherDilbert]

I am in complete agreement with Another Dilbert.

I quit reading a while ago, but at whatever point I left, I am in complete agreement with phavoc.

Nice to hear that someone is still interested!

I’ll try to sum up my own thoughts, theories and observations on the subject this weekend ...

Please do.

 

[Anonymous]

I've decided that from now on, we're just going to use psionic levitation to get the ship off the planet. Then we don't have to think about all these stupid equations. I'll tell them to illuminate the thrusters with a lamp just so that it doesn't look suspicious.

 

[phavoc]

First, let's make sure we get the discussion back on track.

Let's set some agreed upon parameters that need not be continually reviewed:

1) Official designs are not universal within the books, and especially across multiple versions.
2) Traveller makes up some things, but the original premise of the game is to take existing science and physics and extrapolate into the future.
3) Some things, like Grandfather, talking cats, dogs, star-faring centaurs, are probably made up.
4) Counter gravity nullifes the local gravity field, allowing a ship or vehicle to ascend, hover, or descend utilizing a process that essentially ignores local gravity.
5) Anti-gravity does everything counter gravity does, but also allows for lateral movement utilizing a process to generate thrust, or thrust-like conditions.
6) Mass is never ignored, but can be countered.
7) M-drives come in many variations.
8) This discussion centers specifically around LIFT - specifically how do ships take off and land in a 1G environment.
9) There are multiple sets of rules covering Traveller (CT [and revisions], Striker, MT, TNE, T4, FF&S, T5, MGTv1 & v2, D20, HERO... did I get them all??). Nearly all of them add, over-write, remove, or contradict one or more versions.
10) To simplify the discussion let's stick with the version whom we are supporting on this board - MGT (v1 & v2)

While I'm tempted to go back point by point, it is degenerating into uselessness. Clipping quotes and one-liners is just getting stupid.

So, by default, Traveller ships are supposed to operate using the aforementioned parameters. To take off and land on a planet with a 1G gravity they need to more or less obey the current rules of physics and aerodynamics. With the wonderful invention of counter grav, ships that are not tail sitters can maneuver into just about any place and set down, and reverse that process to take off.

Taking off or landing involves thrust and lift. You can generate your thrust from your main engine, or you can generate lift from using your main engines and a lifting surface. The many versions of Traveller offer many variations on this. Some specifically offer CG as part of the design process, some allude to it, most completely ignore all aspects of it.

There is nothing in the current MGT version (1 or 2) that mentions how ships generate enough lift. Therefore something is doing it.

Without citing other versions, explain how MGT tech and MGT ships are able to take off and land.

My response - Using points #1 - #10, MGT ships still have to follow the rules of physics. The ships that have wings or are streamlined could use their wings to gain some lift while entering an atmosphere. The X-series of lifting bodies showed that as possible. But aerodynamics would prohibit them from generating enough lift to take off because their mass and wing / body designs cannot generate enough lift because they are too massive and/or have too much drag.

Ships without wings or lifting-body surfaces that are able to land on a planet (and are not tail sitters), must have some form of lift other than their drive to land. Without CG/AG, the only possible answer is that they have extremely power thrusters that are able to lift a fully loaded ship. It is a possible alternative, however thrusters of that power are as strong as the maneuver drive (to lift the mass in a 1G environment). No mention of such thrusters exists in design books that I am aware of.

Adding cost to the process is a non-sequitur. The cost is already amorphous and has to assume all kinds of things. No additional complication is required nor needed. Merely the acceptance that CG lifting capability is present. This allows ships to fulfill the expected maneuverability, it allows ships to generate sufficient lift to maneuver into hangars and docking facilities, it does not affect any part of the game, and it need not cost anything. "Ships are equipped with counter-grav in order to hover and land". It's as simple as that.

 

[dragoner]

Or did I misunderstand you completely?

Not completely, I meant the mass of the vehicle, you could call out specific gravity of 7 (aluminum is 7.8 iirc) because a ship is essentially hollow, and compute that by your 14 dtons, and then be able to get closer using 9.81ms^2 (though Traveller G's are traditionally a straight 10ms^2) there is more to it; nevertheless, in the equation, time is going to be your main variable. A 1G thrust (quite nice acceleration) could also accelerate in atmosphere until it's velocity carries it out of the atmosphere in a shallow angle.

 

[AnotherDilbert]

Very well...

I will keep addressing your points in short snippets; it easier to discuss specific details that way, than a monologue in your general direction.

1) Official designs are not universal within the books, and especially across multiple versions.
2) Traveller makes up some things, but the original premise of the game is to take existing science and physics and extrapolate into the future.
3) Some things, like Grandfather, talking cats, dogs, star-faring centaurs, are probably made up.

Agreed, editions differ, but we keep science plus some fictional technologies.

4) Counter gravity nullifes the local gravity field, allowing a ship or vehicle to ascend, hover, or descend utilizing a process that essentially ignores local gravity.
5) Anti-gravity does everything counter gravity does, but also allows for lateral movement utilizing a process to generate thrust, or thrust-like conditions.

No, AG and CG are not magic spells defying science by bending and unbending curved space-time selectively. Gravity cannot be ignored, or locally dispelled.

AG is simple: One AG module provides a specified amount of thrust, nothing more, nothing less. It can push you away from the planet or pull you towards it. Gravity, mass, and weight are not affected.

CG is more mysterious but seems somehow provide a lifting force opposed, but never greater than, the current gravitational force. It can never make a craft ascend by imposing a greater lifting force than the downward gravitational force (this is very explicit in TNE). CG craft always needs additional thrusters to be mobile.

Either way the craft and its occupants are still in the full grip of gravity and not weightless. Just like in a helicopter.

6) Mass is never ignored, but can be countered.

No, no inertialess drives. Mass is never changed, countered, or otherwise manipulated. Newton's second lives in all its glory.

7) M-drives come in many variations.

While we can use many different drives for propulsion, the common one aka thruster plates is predominantly used in most editions.

8) This discussion centers specifically around LIFT - specifically how do ships take off and land in a 1G environment.

The discussion can never be about aerodynamic lift alone. We will never get anywhere without thrust.

Note that even HiGrav worlds can have very thin or even no atmosphere, where lift is irrelevant.

Thrust alone is quite enough for take-off and landing, as shown by rockets and VTOL aircraft.

9) There are multiple sets of rules covering Traveller (CT [and revisions], Striker, MT, TNE, T4, FF&S, T5, MGTv1 & v2, D20, HERO... did I get them all??). Nearly all of them add, over-write, remove, or contradict one or more versions.
10) To simplify the discussion let's stick with the version whom we are supporting on this board - MGT (v1 & v2)

I can try to keep to MgT, but since it mostly very carefully avoids locking down details that can be difficult. CT (and MT providing more detail) set the expectations that later editions mostly follows.


As a end note to these points I have to say that simply ignoring my arguments and restating your peculiar view will not convince me of anything.

So, by default, Traveller ships are supposed to operate using the aforementioned parameters. To take off and land on a planet with a 1G gravity they need to more or less obey the current rules of physics and aerodynamics.

Agreed.

With the wonderful invention of counter grav, ships that are not tail sitters can maneuver into just about any place and set down, and reverse that process to take off.

Now you are sneaking in the unwarranted assumption that M-drive thrust is not vectored.

If we stick to MgT we have no CG, but only AG. With vectored thrust AG offers no advantage.

Taking off or landing involves thrust and lift. You can generate your thrust from your main engine, or you can generate lift from using your main engines and a lifting surface. The many versions of Traveller offer many variations on this. Some specifically offer CG as part of the design process, some allude to it, most completely ignore all aspects of it.

Agreed, if by lift you mean any lifting force, not just aerodynamic lift.

Without citing other versions, explain how MGT tech and MGT ships are able to take off and land.

My response - Using points #1 - #10, MGT ships still have to follow the rules of physics. ...

Ships without wings or lifting-body surfaces that are able to land on a planet (and are not tail sitters), must have some form of lift other than their drive to land. Without CG/AG, the only possible answer is that they have extremely power thrusters that are able to lift a fully loaded ship.

So your entire argument is that thrust cannot possibly be vectored, despite being explicit in MT and Gurps? The Hawker Harrier is impossible, and like the bumblebee cannot possibly fly?

You realize that that would make CG craft useless too?

However, all contra-grav vehicles are assumed to have vectored thrust agencies to hold up the remaining fraction of their weight, allowing them to hover.

It is a possible alternative, however thrusters of that power are as strong as the maneuver drive (to lift the mass in a 1G environment). No mention of such thrusters exists in design books that I am aware of.

So, ships must have a system (AG) that is not mentioned or discussed, because they do not have another system (downwards facing thrusters) that is not mentioned or discussed? I would say that would make them both equally unlikely...


Lets see what MgT actually says:

... in the presence of a significant gravity field that field acts as an additional “thrust” on the craft ...

MgT1 HG, p86 (just like LBB2) explicitly says that ships are affected by gravity normally and does not have any extra thrust or way of ignoring gravitational acceleration. Conclusion: they generally have no AG drives.

I have made this argument a few times and you have yet to acknowledge or try to address it. Ignoring it will not make it go away.

Streamlined Hull: A ship designed to fly through atmosphere – will feature a wing or lifting body.
...
A streamlined ship is designed to enter a planetary atmosphere, and can function like a conventional aircraft. ...

Partial streamlining allows a ship to skim gas giants and enter Atmosphere codes of 3 or less, acting in the same way as streamlined ships. In other atmospheres, the ship will be ponderous and unresponsive, reliant on its thrusters to keep it aloft. ...

MgT Core, p137: A streamlined ship can be flown in atmosphere with the Flyer(winged) skill. Ships can't be flown with the Flyer(grav) skill.

Adding cost to the process is a non-sequitur. The cost is already amorphous and has to assume all kinds of things.

No, cost is always a consideration. Otherwise we can just assume that all ships have J-6 and M-9 since that would undoubtedly be convenient.

If we go to MgT2 Vehicle handbook we see that grav craft are much more expensive than ground craft, the difference is probably the grav modules and extra power systems. Scaling that up to starships it would be cost prohibitive.

No additional complication is required nor needed. Merely the acceptance that CG lifting capability is present. This allows ships to fulfill the expected maneuverability, it allows ships to generate sufficient lift to maneuver into hangars and docking facilities, it does not affect any part of the game, and it need not cost anything. "Ships are equipped with counter-grav in order to hover and land". It's as simple as that.

Or you just say "Spacecraft have vectored thrust", no extra cost, complication, or systems required. As specified in MT and Gurps.

 

[Condottiere]

At the moment, I think only three types of gravity based drives are available in the Mongoverse.

The one that vehicles use, and optionally spaceships, would be orientated downwards along the lines of gravitational force, so it's fully efficient in buoyancy, and tends, in my opinion, to be more of a field effect.

 

[phavoc]

You asked earlier about an interplanetary car. Taken from MT 101 Vehicles - TL12 Planet Hopper Grav family car."This high-tech family vehicle permits commuting between planets and their satellites (natural or artificial) or even travel between inner planets when they are in opposition. FYI - there is a crapper but no internal gravity. Max accel is 1.2G. There you have it - the canon family car that takes you from Mars to Earth/Venus/Mercury and all points in between.

4) Counter gravity nullifes the local gravity field, allowing a ship or vehicle to ascend, hover, or descend utilizing a process that essentially ignores local gravity.
5) Anti-gravity does everything counter gravity does, but also allows for lateral movement utilizing a process to generate thrust, or thrust-like conditions.

No, AG and CG are not magic spells defying science by bending and unbending curved space-time selectively. Gravity cannot be ignored, or locally dispelled.

AG is simple: One AG module provides a specified amount of thrust, nothing more, nothing less. It can push you away from the planet or pull you towards it. Gravity, mass, and weight are not affected.

CG is more mysterious but seems somehow provide a lifting force opposed, but never greater than, the current gravitational force. It can never make a craft ascend by imposing a greater lifting force than the downward gravitational force (this is very explicit in TNE). CG craft always needs additional thrusters to be mobile.

Either way the craft and its occupants are still in the full grip of gravity and not weightless. Just like in a helicopter.

At what point did I mention magic? At what point was curved space time mentioned? By the way, the definition of 'contra' means against, opposite, contrasting. Ergo the physical force holding an object down is ignored (or to use your magical analogy, dispelled). Please not this is local and meant to be relevant to the force pulling the object toward the (for example) planetary surface. Unlike your hysterical explanations, it's not physics gone wild and the object is flung off the planet because it is no longer bound by the local space-time locale gravity. Turning on CG doesn't make your object into a projectile to be flung off.

6) Mass is never ignored, but can be countered.

No, no inertialess drives. Mass is never changed, countered, or otherwise manipulated. Newton's second lives in all its glory.

Where, oh where is inertialess mentioned? Or Newton?

8) This discussion centers specifically around LIFT - specifically how do ships take off and land in a 1G environment.

The discussion can never be about aerodynamic lift alone. We will never get anywhere without thrust.

Note that even HiGrav worlds can have very thin or even no atmosphere, where lift is irrelevant.

Thrust alone is quite enough for take-off and landing, as shown by rockets and VTOL aircraft.

No, you are wrong. Look at the thread title - "A lot of worlds over 1g gravity.How do 1G thrust ships take off?" My statement reflects the title of the thread and the original topic asked. LIFT, whether provided by main drive or some other mechanism, is required to get off the ground. If you are going vertical then LIFT is not required. Since you like Wikipedia, here is the first sentence from it -

"A fluid flowing past the surface of a body exerts a force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction.[1] It contrasts with the drag force, which is the component of the force parallel to the flow direction. Lift conventionally acts in an upward direction in order to counter the force of gravity, but it can act in any direction at right angles to the flow."

Things like drag are mentioned (which not surprisingly you don't seem to like to talk a bout). And look (referencing the bold statement above), lift counteracts gravity, but only at right angles. And all those pretty equations from NASA and elsewhere about lift only being generated by a lifting surface with the air flowing underneath the lifting surface. Unfortunately lift equations are not Newtonian. Yes, the equation is insufficient to explain lift and drag and lifting coefficients. So there are actually different equations that do this. Oh, sure, they include some Newtonian things, but they specifically not.

9) There are multiple sets of rules covering Traveller (CT [and revisions], Striker, MT, TNE, T4, FF&S, T5, MGTv1 & v2, D20, HERO... did I get them all??). Nearly all of them add, over-write, remove, or contradict one or more versions.
10) To simplify the discussion let's stick with the version whom we are supporting on this board - MGT (v1 & v2)

I can try to keep to MgT, but since it mostly very carefully avoids locking down details that can be difficult. CT (and MT providing more detail) set the expectations that later editions mostly follows.

As a end note to these points I have to say that simply ignoring my arguments and restating your peculiar view will not convince me of anything.

Unless it specifically states that this rule overwrites the old one you've already established that any rule is valid from any version. There's no peculiarity.

With the wonderful invention of counter grav, ships that are not tail sitters can maneuver into just about any place and set down, and reverse that process to take off.

Now you are sneaking in the unwarranted assumption that M-drive thrust is not vectored.

If we stick to MgT we have no CG, but only AG. With vectored thrust AG offers no advantage.

Sneaking in? Stating the obvious is sneaking in? You state that M-drive thrust is vectored. Where in MGT does it state it is vectored? I don't think it does. And you are seemingly oblivious to the advantages of hovering without blasting your M-drive in vectored mode. And you neglect the other limitations (see below) of this.

Taking off or landing involves thrust and lift. You can generate your thrust from your main engine, or you can generate lift from using your main engines and a lifting surface. The many versions of Traveller offer many variations on this. Some specifically offer CG as part of the design process, some allude to it, most completely ignore all aspects of it.

Agreed, if by lift you mean any lifting force, not just aerodynamic lift.

Aerodynamic lift is a lifting force.

Without citing other versions, explain how MGT tech and MGT ships are able to take off and land.

My response - Using points #1 - #10, MGT ships still have to follow the rules of physics. ...

Ships without wings or lifting-body surfaces that are able to land on a planet (and are not tail sitters), must have some form of lift other than their drive to land. Without CG/AG, the only possible answer is that they have extremely power thrusters that are able to lift a fully loaded ship.

So your entire argument is that thrust cannot possibly be vectored, despite being explicit in MT and Gurps? The Hawker Harrier is impossible, and like the bumblebee cannot possibly fly?

You realize that that would make CG craft useless too?

However, all contra-grav vehicles are assumed to have vectored thrust agencies to hold up the remaining fraction of their weight, allowing them to hover.

Ah, once again you want to cherry pick at things. Lets go ahead and tear your cherry picking apart. A Harrier jet is classified as a S/TOVL - Short Take off / Vertical landing aircraft. From your favorite place, Wikipedia:

The Harrier Jump Jet, capable of taking off vertically, can only do so at less than its maximum loaded weight. In most cases, a short take off is performed, using forward speed to achieve aerodynamic lift, which uses fuel more economically than a vertical take off. On aircraft carriers, a ski-jump ramp is employed at the bow of the carrier to assist the aircraft in becoming airborne. Landings are typically performed very differently. Although a conventional landing is possible, the range of speeds at which this can be done is narrow due to relatively vulnerable outrigger undercarriage. Operationally, a near-vertical landing with some forward speed is preferred. Rotating the vectored thrust nozzles into a forward-facing position during normal flight is called vectoring in forward flight, or "VIFFing". This is a dog-fighting tactic, allowing for more sudden braking and higher turn rates. Braking could cause a chasing aircraft to overshoot and present itself as a target for the Harrier it was chasing, a combat technique formally developed by the USMC for the Harrier in the early 1970"

Why golly, a Harrier can hover or take off using vectored thrust! Ergo your starship example can do the same thing! Now, lets apply the rest of the Harrier physics. Using vectored thrust it is unable to take off fully loaded. So going back to your Type-R example, it, too, would be unable to take off. Oh I'm sure you are going to argue either Type-R have more power available, thus they can do it. Or else the ship would overload their engines/power plant to do so.

Oops, MGT rules state that overpower engines or power plant incurs a risk. Therefore each time a fully loaded Type-R attempted to take off or land the engineer would have to roll and see if they blew out their engine, which would have a deleterious effect on the hull when it came crashing down.

You postulated that the MGT rule citing cumulative risk for each attempt could be erased via maintenance. Since you are against the concept of the inclusion of CG lifters because of cost or added complexity, you've now just interjected additional cost and added complexity into your model.

Some dude named Occam came up with a theory (must been while he was shaving) in explaining a thing no more assumptions should be made than are necessary. The principle is often invoked to defend reductionism or nominalism. Your assumptions are far more complex than mine, and have to span multiple rule sets in an attempt to justify them. Vectored thrust has limitations. SSOM (look at the pretty picture) states lateral thrust is only 25%. Using your aforementioned thrust plate (adopted by multiple rule sets), your logic fails. A thrust place pushed to the aft at 100% power. Laterally it is only capable of 25% force, and forward only 10%. Using our lovely Type-R trader, it is capable of vectoring only 25% of it's force laterally, above or below. Anything else requires overloading, which by it's very definition is adding stress above normal parameters. Per MGT you can only overload your drive by 10% (with the risk of causing damage). So, using Newton, err, simple math:

1G drive * 10% overload = 1.1G drive. 25% of 1.1 is .275G worth of thrust available to vector downwards. So your vectored thrust cannot work because it is insufficient. This going back to a previous point I made in regards to SSOM. Page 3 of SSOM covers your overdrive rules.

"Pushing the Drive Limits: If called upon to do so, a vessel can force the maneuver drive beyond its normal operating limits for a period of time, but this must be undertaken with care. Using overdrive is the most common way for a ship with a maneuver drive less than 4G to hover in a lateral attitude, rather than in a nose position.

The more pronounced the overdrive, the closer the engineer must monitor the drive status. The plates may be overdrive by up to 40% for extended periods of time (days) with few harmful effects if the overage is done skillfully.

On the other hand, overdriving plates by 400% (as in the case of a 1G ship trying to do a lateral hover at takeoff or landing) takes the utmost care, and can only be done for brief periods of time (under 5 minutes). While overdriving the plates at such extreme levels, the engineer must pa very close attention tot he drives to make sure no overloads develop or warning lights appear."

In a previous post I incorrectly stated drives are not capable of 400% overdrive. That point you were correct on. By quoting the entire section, rather than an incomplete sentence, we gain a fuller understanding of the issue. For MT, the type-R is capable of overdriving, with risk, to land or takeoff in a 1G environment. However, to the point of the post, a planet with more than 1G rating would prohibit 1G ships from taking off or landing. MGT rules do not permit 400% overages. Mixing the rule sets means either picking and choosing what you want from each (4x vs.10%), or keeping them each separate, thus rendering MGT ships incapable of using thrusters to do this.

It is a possible alternative, however thrusters of that power are as strong as the maneuver drive (to lift the mass in a 1G environment). No mention of such thrusters exists in design books that I am aware of.

So, ships must have a system (AG) that is not mentioned or discussed, because they do not have another system (downwards facing thrusters) that is not mentioned or discussed? I would say that would make them both equally unlikely...

Ships must have a system that matches the extrapolation of reality that has already been acknowledged and affirmed. A thruster system equivalent in power to the main drive needs to be equivalent in size. That size can be spread around in multiple places, but equivalency requires this. As you have continually stated you prefer words to pictures, and rules to assumptions. I have continually asserted a CG (notice, not AG) system that provides a ship the capability to maneuver in confined docking spaces while under gravity is a requirement based upon the other aspects related to starships. Your assertion that both would be equally unlikely doesn't make any sense. BOTH systems are mentioned elsewhere in different versions.

Again, going back to Occam's razor theory, no more assumptions than necessary should be used to explain something. CG lift provides for the ability to lift off in any gravity field. CG lift is specifically called out in GURPS and is identified in many of the designs. Overpowering the thrusters is called out in SSOM. Overpowering is specifically mentioned in both SSOM and MGT that there is an implicit danger to this. SSOM specifies you can overpower to 400%, MGT specifies no more than 10%. So right there is a conflict in the rules. CG, however, has no conflict in the rules. BOTH, however, also suffer from not being specifically called out in the rules. As has already been specified, MGT is rather light when it comes to details. Again Occam's razor comes into play here as the most logical explanation that requires the least number of assumptions.

Lets see what MgT actually says:

... in the presence of a significant gravity field that field acts as an additional “thrust” on the craft ...

MgT1 HG, p86 (just like LBB2) explicitly says that ships are affected by gravity normally and does not have any extra thrust or way of ignoring gravitational acceleration. Conclusion: they generally have no AG drives.

I have made this argument a few times and you have yet to acknowledge or try to address it. Ignoring it will not make it go away.

Another non-sequitur cherrypick. In this case you are quoting from the alternative movement section. Notice the entire section deals with starship movement in space. This has absolutely NOTHING to do with the original discussion. But let's run with your quotation and provide the ENTIRE section so that all can see how useless it is in this discussion. For those who choose not to look this up, the specific discussion is centered around starships in the gravity well of a small gas giant (an image is provided):

"Effect of Gravity - When fighting in the presence of a significant gravity field that field acts as an additional “thrust” on the craft fighting within it. For combat purposes only gravity fields of 1G or more significantly above the planet’s surface are considered significant and hence only fields
around gas giants are considered. If a ship contacts the surface of a planet at a speed of more than 1 unit per turn it is assumed to be destroyed (either burnt up or crashed). If at any stage the path of a vessel lies within the gravity field of a body, it attracts thrust as shown below as an additional change in vector at Step 3 above."

The section talks about the attraction of gravity on a ship and how a vessel in a straight-line movement will be pulled towards the gravity well of the gas giant. Conclusion: AG drives, or thruster plates, or chemical rockets would all fit within the same parameters for movement. Further conclusion - nothing you said is germane to the discussion. At no point has anyone, but you, tried to interject movement of ships in space and equate them with movement of ships trying to take off or land.

Streamlined Hull: A ship designed to fly through atmosphere – will feature a wing or lifting body.
...
A streamlined ship is designed to enter a planetary atmosphere, and can function like a conventional aircraft. ...

Partial streamlining allows a ship to skim gas giants and enter Atmosphere codes of 3 or less, acting in the same way as streamlined ships. In other atmospheres, the ship will be ponderous and unresponsive, reliant on its thrusters to keep it aloft. ...

MgT Core, p137: A streamlined ship can be flown in atmosphere with the Flyer(winged) skill. Ships can't be flown with the Flyer(grav) skill.

As usual, you have neglected the other quotations provided on lifting bodies. In all the research done on lifting bodies, none of the experimental craft took off from the ground. In fact, if you look at the origin of lifting bodies, they were designed for controlled descents from orbit. And all of the experiments involved the lifting body craft being carried aloft by a B-52 and dropped. Any climbing was done via their rocket engines. I can put a rocket engine on a brick and it can gain altitude. Doesn't mean it is flying or generating enough lift on it's own. The lifting bodies, much like the space shuttle's wings, allow the craft to have a controlled descent and the forward speed of the craft allows the wings to generate some lift - but only when moving at higher speeds. A brick falling from the sky will generate lift by virtue of air crossing it's boundaries (assuming, of course it has some angular velocity. Wikipedia already states it must move at right angles). I believe no one, including yourself, is going to argue the brick is capable of flying. Capable of falling, yes. Just like the shuttle or an X-34 can fall in a controlled fashion. But it is not flying, and it's certainly not ascending based upon lift generated from it's lifting surfaces. With a rocket it is possible.

Here is a link to an article about Martin aircraft, which built the first lifting bodies. If you look at the illustration on pg 8 you will see the lifting bodies were designed to fly in one direction - down. the lift was meant to increase landing opportunities and to be a more robust method of returning from orbit. The comparison is made against the Apollo craft (zero or very low lift) and the lifting bodies (substantial lift). The paper showcases a LOT of data on the subject. (Bonus point to me - a brick is called out on the glide angle chart on page 11.. discovered after the comment below. )

Per your quotes above, ships are able to fly so long as they have power. Flying implies forward movement. Lift requires a great deal of forward movement, the more mass an object has the more more forward movement and lifting surfaces are required. If you want to say that all of that is combined that's certainly your perogative. But a far simpler explanation that uses common sense is that CG lifters are present and simply not detailed.

Adding cost to the process is a non-sequitur. The cost is already amorphous and has to assume all kinds of things.

No, cost is always a consideration. Otherwise we can just assume that all ships have J-6 and M-9 since that would undoubtedly be convenient.

If we go to MgT2 Vehicle handbook we see that grav craft are much more expensive than ground craft, the difference is probably the grav modules and extra power systems. Scaling that up to starships it would be cost prohibitive.

No, it's really not. Do we know how much the windows on the bridge cost? No. Do we know if you add a crapper in the ship it costs X more credits? Nope. I don't think the rules actually state how much an extra crapper is going to be. I guess, using your reasoning all ships are equipped with anti-matter drives, too. After all if we are going to use silly reasoning lets crank it up a notch.

You, again, fail to see reason. A starship hull has a multitude of equipment, items and fittings on it. Not everything is listed. For example - landing gear isn't mentioned. It's cost is assumed to be included. Tanks to store O2 are assumed to be included. Extra crappers (latrines for you ground pounders, heads for the navy folks) are assumed to be included (specifically those outside of the staterooms). Lots of things are included in the base cost. There is no reason, other than your insistence that they must be included, to be there. In the systems that specifically call these items out (such as GURPS), they are specifically listed in the ship descriptions for those that would have them.

As far as grav equipment being more expensive than ground craft, duh? A BMW is more expense than an Opel, no? Grav vehicles are the top end of vehicles, and as such it is only common sense that they would be more expensive than ground craft. Isn't that a logical and obvious conclusion - which has no real bearing on the discussion?

No additional complication is required nor needed. Merely the acceptance that CG lifting capability is present. This allows ships to fulfill the expected maneuverability, it allows ships to generate sufficient lift to maneuver into hangars and docking facilities, it does not affect any part of the game, and it need not cost anything. "Ships are equipped with counter-grav in order to hover and land". It's as simple as that.

Or you just say "Spacecraft have vectored thrust", no extra cost, complication, or systems required. As specified in MT and Gurps.

Your statement is incorrect. Per the rules you have cited, for that to work the ships would have to overdrive their maneuvering systems to generate sufficient lift. And even per SSOM, a 1.1G planetary gravity would make it impossible for a ship with 1G drives to take off, since it is exceeding the 400% capability of the overdrive (which is also 390% in excess of what is allowed under MGT).

So no, ships having vectored thrust does not satisfy the needs.

(edited to reduce the snarkiness and finish).

Next!

 

[Old School]

So I haven’t been following all the back and forth, but I thought it might be helpful for ya’ll to explain this terms of an example.

I have attached a picture of an Imperial Treasure Ship, which is a 1600 ton, 1G capable ship opersted by the Imperial Navy. In the Pirates of Drinax adventure “Treasure Ship”, this ship lands and later departs from the downport on Acrid under its own power. Acrid is a size A, 1.4 G world, with a violent atmosphere that requires atmospheric weather control to allow ships to land safely.

Can each of you involved in this debate explain the process by which this ship lands and takes off?

 

[phavoc]

So I haven’t been following all the back and forth, but I thought it might be helpful for ya’ll to explain this terms of an example.

I have attached a picture of an Imperial Treasure Ship, which is a 1600 ton, 1G capable ship opersted by the Imperial Navy. In the Pirates of Drinax adventure “Treasure Ship”, this ship lands and later departs from the downport on Acrid under its own power. Acrid is a size A, 1.4 G world, with a violent atmosphere that requires atmospheric weather control to allow ships to land safely.

Can each of you involved in this debate explain the process by which this ship lands and takes off?

Sure. Per my view, starships have an integral counter-grav capability that allows them to land and take off from planets and other gravity wells. The counter-grav nullifies gravities pull on the ship, allowing it to ascend, hover or descend. The ships thrusters are used to spin or change angle of attack. They operate the same as they would in zero-G - thus while the gravity well pull is nullified, the ship still has mass, just as it would in a zero-g environment. So movements are what you would expect from maneuvering thrusters, for each burn clockwise, an equal burn is required in the opposite direction to halt the movement. Which can be easily handled via manual or computer control.

Once the ship has obtained the necessary altitude the main engines, or even thrusters, are used to begin maneuvering it away from it's docking location. So if the ship was in a standard downport docking facility/warehouse, it would either ascend up through a retracted roof or back out the hangar door assuming it pulled in like a conventional garage. At some starports it may need to taxi away from the docking area to reach the designated area to begin it's ascent (much like a plane does on a taxi way). Other places it could vertically ascend to a height, then fire off it's main drive to begin the trip to orbit. In any case it's still subject to normal aerodynamic issues, such as wind shear, turbulence, etc. Once it's drive is fully functioning it may turn off it's CG for lifting. In the case of a 1.4G world and a 1G ship, and in this case ,the shape of the ship, I would assume the ship would require the extra lift from the CG system until it had reached a high enough velocity or the pull of gravity was less than the ability of the ship's drive to maneuver.

 

[AnotherDilbert]

By your method ALL versions are simultaneously relevant and canon. I'm sure you are going to argue that's not, but that's to be expected.

Neither did you, contragrav is not in MgT.

We can hardly pretend that earlier editions don't exist and form the foundation for later editions.

You asked earlier about an interplanetary car. Taken from MT 101 Vehicles - TL12 Planet Hopper Grav family car."This high-tech family vehicle permits commuting between planets and their satellites (natural or artificial) or even travel between inner planets when they are in opposition.

Thank you, I don't have that. Pity that they didn't read their own rules...

4) Counter gravity nullifes the local gravity field, ...

At what point did I mention magic? At what point was curved space time mentioned?

Gravity is the perceived force caused by space-time curvature. If you say one, you say the other.

To 'nullify' one aspect of gravity, while not others, is what I call magical. As before If you 'nullify' gravity on an object it would be left behind as the planet (and star) accelerates away in its orbit. You did want basic science to work as usual?

By the way, the definition of 'contra' means against, opposite, contrasting. Ergo the physical force holding an object down is ignored (or to use your magical analogy, dispelled).

Contra-grav would mean against gravity, not ignores gravity. That would be null-grav or something like that?

By the name alone it is reasonably a force that opposes the force imposed by gravity?

Please not this is local and meant to be relevant to the force pulling the object toward the (for example) planetary surface. Unlike your hysterical explanations, it's not physics gone wild and the object is flung off the planet because it is no longer bound by the local space-time locale gravity. Turning on CG doesn't make your object into a projectile to be flung off.

Gravity is the force that keeps the ship bound to the planet. Nullify that force and they will separate. That is not 'physics gone wild', but simple Newtonian mechanics.

Ignoring one consequence of that force, while continuing to use another consequence, is what I call magic.

Is that a simple enough explanation?

It's simple, but completely ignores the last four centuries of science.

6) Mass is never ignored, but can be countered.

Where, oh where is inertialess mentioned? Or Newton? I gotta ask, do you have like a virtual something for Newton?

Countering mass means countering inertia. Newton's second is the law about inertia.

And please stop speculating about my proclivities or state of mind and address the arguments.

What is the point? Shall we say ice is cold, snow is cold, adding solid water to a beverage at room temperature will lower the the beverages temperature? I stated they came in many variations, you agreed. Stating you agreed would have been simpler.

I can simplify my answer: M-drive means thruster plates, unchanged since 1980 or at least MT. So, no, M-drives do not vary.

The discussion can never be about aerodynamic lift alone. We will never get anywhere without thrust.

No, you are wrong. Look at the thread title - "A lot of worlds over 1g gravity.How do 1G thrust ships take off?" My statement reflects the title of the thread and the original topic asked. LIFT, whether provided by main drive or some other mechanism, is required to get off the ground. If you are going vertical then LIFT is not required. Since you like Wikipedia, here is the first sentence from it -

"A fluid flowing past the surface of a body exerts a force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction.[1] It contrasts with the drag force, which is the component of the force parallel to the flow direction. Lift conventionally acts in an upward direction in order to counter the force of gravity, but it can act in any direction at right angles to the flow."

Yes, that describes aerodynamic lift. And how is that generated without forward motion caused by thrust?

Another way of taking off from a planet is with thrust. You know, like rockets?

Even the US has managed to produce a VTOL aircraft by now, so the principle of vertical take off on thrust alone can't be completely unknown?

So we'll go back to quoting all rules again. Unless it specifically states that this rule overwrites the old one you've already established that any rule is valid from any version.

So, we are down to the level of strawman arguments now?

I have obviously never said that.

There's no peculiarity. When you leave out relevant facts, or introduce non-sequitur statements they will indeed be over-ruled.

You can choose to ignore anything you like, of course. But if you want to communicate you have to engage with counter-arguments.

Sneaking in? Stating the obvious is sneaking in?

Your conclusion assumed that thrust could not be vectored without mentioning it. Yes, I call that sneaking it in.

You state that M-drive thrust is vectored. Where in MGT does it state it is vectored? I don't think it does.

Vectored thrust is not mentioned in MgT as far as I know. Where in MgT is it stated that ships generally use contra-grav? Or even contra-grav at all?

And you are seemingly oblivious to the advantages of hovering without blasting your M-drive in vectored mode. And you neglect the other limitations (see below) of this.

No, I have repeatedly agreed that AG would be convenient. But I think it isn't necessary and it comes at a cost.

Agreed, if by lift you mean any lifting force, not just aerodynamic lift.

Aerodynamic lift is a lifting force.

Agreed, it is A lifting force, but it is not the only possible lifting force. E.g. thrust from the M-drive or AG can also be used as a lifting force by pointing it in the opposite direction of gravitational pull.

Ah, once again you want to cherry pick at things. Lets go ahead and tear your cherry picking apart. A Harrier jet is classified as a S/TOVL - Short Take off / Vertical landing aircraft. ...

Why golly, a Harrier can hover or take off using vectored thrust! Ergo your starship example can do the same thing!

Glad we agree that vectored thrust is possible, which you seemed to discount as a possibility earlier.

You concluded that ships must have AG since otherwise they could not take off vertically. I showed another possibility. Hence I do not think your conclusion is valid.

That obviously states nothing about any other craft.


Oh, and you seemed to overlook this part:

You realize that that would make CG craft useless too?

However, all contra-grav vehicles are assumed to have vectored thrust agencies to hold up the remaining fraction of their weight, allowing them to hover.

Now, lets apply the rest of the Harrier physics. Using vectored thrust it is unable to take off fully loaded. So going back to your Type-R example, it, too, would be unable to take off. Oh I'm sure you are going to argue either Type-R have more power available, thus they can do it. Or else the ship would overload their engines/power plant to do so.

Nice strawman you got there... Showing that vectored thrust is possible by example does not mean that all aircraft have it nor that all aircraft are identical.

Oops, MGT rules state that overpower engines or power plant incurs a risk. Therefore each time a fully loaded Type-R attempted to take off or land the engineer would have to roll and see if they blew out their engine, which would have a deleterious effect on the hull when it came crashing down.

MgT clearly state that streamlined ships, like the Subbie, fly like aircraft.

Whereas in MT drives needed to be overdriven, and were able to be overdriven, that was apparently not necessary in Gurps (nor in TNE or T5). As I believe we agreed, details differ between editions.

You postulated that the MGT rule citing cumulative risk for each attempt could be erased via maintenance. Since you are against the concept of the inclusion of CG lifters because of cost or added complexity, you've now just interjected additional cost and added complexity into your model.

I assume the required engineers and maintenance staff carried on ships continuously perform routine maintenance, don't you? That routine maintenance of jump drives is required after each jump is mentioned in CT.

Some dude named Occam came up with a theory (must been while he was shaving) in explaining a thing no more assumptions should be made than are necessary. ... Your assumptions are far more complex than mine, and have to span multiple rule sets in an attempt to justify them.

Another strawman.

What we actually said:

"Ships are equipped with counter-grav in order to hover and land". It's as simple as that.

Or you just say "Spacecraft have vectored thrust", no extra cost, complication, or systems required. As specified in MT and Gurps.

I did not say you have to use the most complicated system in any edition, combined with a similar system in another edition that is obviously incompatible with the first system.

Vectored thrust has limitations. SSOM (look at the pretty picture) states lateral thrust is only 25%. Using your aforementioned thrust plate (adopted by multiple rule sets), your logic fails. A thrust place pushed to the aft at 100% power. Laterally it is only capable of 25% force, and forward only 10%. Using our lovely Type-R trader, it is capable of vectoring only 25% of it's force laterally, above or below. Per MGT you can only overload your drive by 10% (with the risk of causing damage).

Yes, by MT, but not by TNE, Gurps, or T5 as far as I know.

Note that the MT overload and the MgT overdrive systems are two different cases. In MgT the Subbie can overdrive the M-drive by 100% for several rounds (for combat). In MT it can overload the M-drive by 400% but only for less than a single round (for landing). In Gurps it appears that we can vector the drive without any reduced efficiency or overloading.

I would obviously not suggest that we use the incompatible systems in MT, Gurps, and MgT at the same time, any more than I believe you would suggest that we use the incompatible AG/CG systems in MT, Gurps, and MgT at the same time.

I merely suggest that we can use other editions to fill in details that are glossed over in the current edition, but fleshed out in earlier editions. And that of course goes for M-drives and AG both.

"Pushing the Drive Limits: If called upon to do so, a vessel can force the maneuver drive beyond its normal operating limits for a period of time, ... "

By quoting the entire section, rather than an incomplete sentence, we gain a broader understanding. For MT, the type-R is capable of overdriving, with risk, to land or takeoff in a 1G environment.

So, we agree that vectored thrust was possible and ships could land vertically without AG, in MT at least.

However, to the point of the post, a planet with more than 1G rating would prohibit 1G ships from taking off or landing.

Agreed, yes, generally, but the Subbie has wings so can add lift to the equation.

As I tried to say in my first post:

So, how does ships take-off from hi-grav planets? Either they have wings and can fly like airplanes (cf. Subsidised Merchant) or they simply don't land (and use a highport instead).

This makes a M-2 drive very useful.

To land on a hi-grav planet you need either wings or high thrust.

However, MGT rules do not permit 400% overages. Mixing the rule sets means either picking and choosing what you want from each (4x vs.10%), or keeping them each separate, thus rendering MGT ships incapable of using thrusters to do this.

I would suggest we use one system at a time, either MT with 25% lateral thrust and 400% overdrive, Gurps ( and perhaps TNE and T5) 100% lateral thrust and no overdrive, or perhaps 50% lateral thrust and 100% overdrive in MgT2?

 

[Condottiere]

Actually, this would be resolved if Mongoose Second kept the Orders option from Mongoose First:

Maximum Speed
Initiative Cost: Four
Type: Combat
Requirements: None
All available power is allocated to the engines. The ship may only fire half its turrets and bays this round, rounding down, but may increase its Thrust by One.

 

[phavoc]

Neither did you, contragrav is not in MgT.

We can hardly pretend that earlier editions don't exist and form the foundation for later editions.

Fair enough. Anti-gravity, specifically, is called out in MGT. But, as we've seen in other versions, the terms are interleavened. For purposes of lift I have used them as such. I have actually specified that, but you have wanted to cut them apart. So we will use anti-gravity in place of contragravity for MGT. Which still doesn't negate the lift issue. If anything it would mean ships have more capabilities.

Gravity is the perceived force caused by space-time curvature. If you say one, you say the other.

To 'nullify' one aspect of gravity, while not others, is what I call magical. As before If you 'nullify' gravity on an object it would be left behind as the planet (and star) accelerates away in its orbit. You did want basic science to work as usual?

In space, zero-G, gravity is nullifed. Amazingly enough you can still nullify gravity in orbit and stay attracted to a planetary body. Using your analogy above the ISS should be left behind as the planet (and star) accelerate away from it. So I guess the ISS is violating the space-time curvature?

And, from the dictionary, nul·li·fy - make of no use or value; cancel out. The word was used correctly.

Contra-grav would mean against gravity, not ignores gravity. That would be null-grav or something like that?

By the name alone it is reasonably a force that opposes the force imposed by gravity?

Nope. Check the dictionary again. You want to be specious and play word games with definitions. But it's not germane to the discussion.

Gravity is the force that keeps the ship bound to the planet. Nullify that force and they will separate. That is not 'physics gone wild', but simple Newtonian mechanics.

Ignoring one consequence of that force, while continuing to use another consequence, is what I call magic.

You are magically ignoring we have objects orbiting our planet, in zero-g, that remain in place. Or do you want to say those objects in space orbiting our planet are violating simple Newtonian physics? They either are, or they are not.

Is that a simple enough explanation?

It's simple, but completely ignores the last four centuries of science.[/quote]

Again a big, fat nope. All anti-grav/contragrav is doing is replicating the effect an object in space has closer to the surface of a planet.

6) Mass is never ignored, but can be countered.

Where, oh where is inertialess mentioned? Or Newton? I gotta ask, do you have like a virtual something for Newton?

Countering mass means countering inertia. Newton's second is the law about inertia.

And please stop speculating about my proclivities or state of mind and address the arguments.[/quote]

Newton's laws:

First law: In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force.
Second law: In an inertial frame of reference, the vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration a of the object: F = ma. (It is assumed here that the mass m is constant.)
Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.

Newtons second law deals with forces upon an object. Inertia is the first law. If you wanted to be correct then you should have referenced his 3rd law (countering inertia). However if you look at my statement I said "mass is never ignored, but can be countered". Antigravity, as you so pointed out, is countering it.

Again, non-sequitur argument. My speculation about Newton is in reference to your continued desire to drag it in and bring up an obtuse, non-sequitur argument. You have studiously ignored all other physical laws but his even though it has been pointed out time and again you cannot use just his laws. Like all of science Newton's work is a build block, one upon the other.

I can simplify my answer: M-drive means thruster plates, unchanged since 1980 or at least MT. So, no, M-drives do not vary.

Fine. We will agree thruster plates.

Yes, that describes aerodynamic lift. And how is that generated without forward motion caused by thrust?

Another way of taking off from a planet is with thrust. You know, like rockets?

Even the US has managed to produce a VTOL aircraft by now, so the principle of vertical take off on thrust alone can't be completely unknown?

Very true. And, by definition, a rocket generates zero lift.

You state that M-drive thrust is vectored. Where in MGT does it state it is vectored? I don't think it does.

Vectored thrust is not mentioned in MgT as far as I know. Where in MgT is it stated that ships generally use contra-grav? Or even contra-grav at all?

Neither is mentioned. Therefore we both must be wrong.

No, I have repeatedly agreed that AG would be convenient. But I think it isn't necessary and it comes at a cost.

What cost? According to MGTv1 CRB, a standard hull (a wedge, cone, sphere or cylinder), "A standard-hull ship may still enter atmosphere but is very ungainly and ponderous, capable only of making a controlled glide to the surface. Getting it back into space requires an elaborate launch setup and considerable expense." By the rules both of us, again, appear to be wrong. Or else the rules are wrong.

Agreed, it is A lifting force, but it is not the only possible lifting force. E.g. thrust from the M-drive or AG can also be used as a lifting force by pointing it in the opposite direction of gravitational pull.

Yeah, according to the definition it is - https://en.wikipedia.org/wiki/Lift_(force)

A fluid flowing past the surface of a body exerts a force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction.[1] It contrasts with the drag force, which is the component of the force parallel to the flow direction. Lift conventionally acts in an upward direction in order to counter the force of gravity, but it can act in any direction at right angles to the flow.

If the surrounding fluid is air, the force is called an aerodynamic force. In water or any other liquid, it is called a hydrodynamic force.

Dynamic lift is distinguished from other kinds of lift in fluids. Aerostatic lift or buoyancy, in which an internal fluid is lighter than the surrounding fluid, does not require movement and is used by balloons, blimps, dirigibles, boats, and submarines. Planing lift, in which only the lower portion of the body is immersed in a liquid flow, is used by motorboats, surfboards, and water-skis.

You realize that that would make CG craft useless too?

However, all contra-grav vehicles are assumed to have vectored thrust agencies to hold up the remaining fraction of their weight, allowing them to hover.

Nope, didn't ignore it. Analyze that statement. It violates even the book definition of what anti-gravity is. Oh, and we don't need to worry about that since all those anti-gravity vehicles got flung off the face of the planet the moment they turned on their anti-grav, right?

Now, lets apply the rest of the Harrier physics. Using vectored thrust it is unable to take off fully loaded. So going back to your Type-R example, it, too, would be unable to take off. Oh I'm sure you are going to argue either Type-R have more power available, thus they can do it. Or else the ship would overload their engines/power plant to do so.

Nice strawman you got there... Showing that vectored thrust is possible by example does not mean that all aircraft have it nor that all aircraft are identical.

Strawman how? I took your explanation and added in the facts. You cited the Harrier as an example of a craft with vectored thrust and it can take off. I proved the other part of the equation in that it cannot do so fully loaded. That's not a strawman. It's an inconvenient fact for you.

MgT clearly state that streamlined ships, like the Subbie, fly like aircraft.

Whereas in MT drives needed to be overdriven, and were able to be overdriven, that was apparently not necessary in Gurps (nor in TNE or T5). As I believe we agreed, details differ between editions.

You forgot that you quoted how the game is supposed to be an extrapolation of current physics? You forgot that in reality the lifting body aircraft were never capable of taking off, just making controlled descents? You forget the definition of lift that has been provided multiple times (and even quotes from the boys at NASA? You forget the section of GURPS starships I quoted word for word that covered whether or not a ship could actually fly using its hull as a lifting body?

I assume the required engineers and maintenance staff carried on ships continuously perform routine maintenance, don't you? That routine maintenance of jump drives is required after each jump is mentioned in CT.

Have you ever done maintenance on a vehicle that is run at 110% at all times? Everything breaks down faster, everything needs to be repaired sooner. No naval ship runs at 110% power all the time for just routine maneuvers. It's stressful on the components and it's beyond "normal" maintenance. Military land vehicles are the same way. Look up the definition of routine.

Another strawman.

No, he was an actual man. Evidently if someone says something you don't like it's a strawman. Gotcha.

Vectored thrust has limitations. SSOM (look at the pretty picture) states lateral thrust is only 25%. Using your aforementioned thrust plate (adopted by multiple rule sets), your logic fails. A thrust place pushed to the aft at 100% power. Laterally it is only capable of 25% force, and forward only 10%. Using our lovely Type-R trader, it is capable of vectoring only 25% of it's force laterally, above or below. Per MGT you can only overload your drive by 10% (with the risk of causing damage).

Yes, by MT, but not by TNE, Gurps, or T5 as far as I know.

Note that the MT overload and the MgT overdrive systems are two different cases. In MgT the Subbie can overdrive the M-drive by 100% for several rounds (for combat). In MT it can overload the M-drive by 400% but only for less than a single round (for landing). In Gurps it appears that we can vector the drive without any reduced efficiency or overloading.

I would obviously not suggest that we use the incompatible systems in MT, Gurps, and MgT at the same time, any more than I believe you would suggest that we use the incompatible AG/CG systems in MT, Gurps, and MgT at the same time.

I merely suggest that we can use other editions to fill in details that are glossed over in the current edition, but fleshed out in earlier editions. And that of course goes for M-drives and AG both.

You cannot take the specifications from one rule system and apply them to the other without also taking the limitations. And you continue to ignore the limitation rules for MGT on overdrive.

However, to the point of the post, a planet with more than 1G rating would prohibit 1G ships from taking off or landing.

Agreed, yes, generally, but the Subbie has wings so can add lift to the equation.

And they also add drag, canceling out the lift.

I would suggest we use one system at a time, either MT with 25% lateral thrust and 400% overdrive, Gurps ( and perhaps TNE and T5) 100% lateral thrust and no overdrive, or perhaps 50% lateral thrust and 100% overdrive in MgT2?

Overloading the drive is a difficult (10+) roll. It only increases thrust for one round. There is a cumulative effect (-2 on your roll) EACH time it is attempted. The attempt will increase the drive thrust by 1. This penalty may be removed by performing additional maintenance on the drive for 1D hours. That's extra work just to take off or land. If you reference SSOM you only get 25% lateral thrust. It seems to me that the risk of getting a critical hit to the drive each time you take off or land should never be considered normal.

 

[AnotherDilbert]

Ships must have a system that matches the extrapolation of reality that has already been acknowledged and affirmed.

Agreed.

A thruster system equivalent in power to the main drive needs to be equivalent in size. That size can be spread around in multiple places, but equivalency requires this. As you have continually stated you prefer words to pictures, and rules to assumptions.

Agreed.

I have continually asserted a CG (notice, not AG) system that provides a ship the capability to maneuver in confined docking spaces while under gravity is a requirement based upon the other aspects related to starships.

Quite, you have made yourself clear, and I disagree.

Your assertion that both would be equally unlikely doesn't make any sense. BOTH systems are mentioned elsewhere in different versions.

Both are an additional extra system, and I consider both equally unnecessary, and hence equally unlikely to be standard on all ships.


I hope this demonstrates why I split your text in small snippets and answers each separately. I believe I can show exactly what I agree and disagree with.

Again, going back to Occam's razor theory, no more assumptions than necessary should be used to explain something.

When we don't agree on what assumptions are necessary, we will not agree what result Occam has on the situation under discussion. Note that I invoked Occam by implication in the post you quote. We both think we have the simpler solution; Occam will not resolve the argument.

CG lift provides for the ability to lift off in any gravity field.

I disagree, and sorry I have to quote Gurps to explain why since MgT does not have CG:

CONTRAGRAVITV SYSTEMS
...
Each module counteracts 450 stons of weight at TL8. 1,500 stons at TL9, and 5,000 stons at TL10+.

So, each module counteracts a limited amount of WEIGHT. Weight depends on local gravity.

Example: Take a TL8 (Edit: TL8, not TL9) ship with a mass of 1000 stons and two CG modules.

In a 1 g gravity field it would weigh 1 × 1000 = 1000 ston, of which 2 × 450 = 900 ston is counteracted. The remaining 100 ston of weight would have to be overcome by lift or drive thrust.

In a 2 g gravity field it would weigh 2 × 1000 = 2000 ston, of which 2 × 450 = 900 ston is counteracted. The remaining 1100 ston of weight would have to be overcome by lift or drive thrust, which might not be possible.


So, if you add too much mass to the ship, or tries to take off in too high gravity, it will not work.

CG lift is specifically called out in GURPS and is identified in many of the designs.

Agreed.

Overpowering the thrusters is called out in SSOM. Overpowering is specifically mentioned in both SSOM and MGT that there is an implicit danger to this. SSOM specifies you can overpower to 400%, MGT specifies no more than 10%. So right there is a conflict in the rules.

The basic point, in my opinion is vectored thrust. Overloading is handled differently in different systems, explicitly MT, Gurps, and MgT.

CG, however, has no conflict in the rules.

Of course, CG does not exist in MgT.

BOTH, however, also suffer from not being specifically called out in the rules. As has already been specified, MGT is rather light when it comes to details.

Agreed.

Again Occam's razor comes into play here as the most logical explanation that requires the least number of assumptions.

And I still disagree. I believe assuming that M-drives have vectored thrust as in earlier editions, is simpler than adding another drive system.

Another non-sequitur cherrypick. In this case you are quoting from the alternative movement section. Notice the entire section deals with starship movement in space. This has absolutely NOTHING to do with the original discussion.

That system is a simple 2D representation of Newtonian mechanics. That is the system that results in the travel time formulas. This is how ships, and all other objects, move, e.g real rockets.

Note that in the original version includes Atmospheric Braking (LBB2, p34) in the same system, so it can explicitly be used for ships in atmosphere.

You used the MgT2 overdrive rules from the combat system to use in routine landing operations earlier in this post, so I'm a bit surprised you consider this irrelevant.

But let's run with your quotation and provide the ENTIRE section so that all can see how useless it is in this discussion. For those who choose not to look this up, the specific discussion is centered around starships in the gravity well of a small gas giant (an image is provided):

"Effect of Gravity - When fighting in the presence of a significant gravity field that field acts as an additional “thrust” on the craft fighting within it. For combat purposes only gravity fields of 1G or more significantly above the planet’s surface are considered significant and hence only fields around gas giants are considered. If a ship contacts the surface of a planet at a speed of more than 1 unit per turn it is assumed to be destroyed (either burnt up or crashed). If at any stage the path of a vessel lies within the gravity field of a body, it attracts thrust as shown below as an additional change in vector at Step 3 above."

The section talks about the attraction of gravity on a ship and how a vessel in a straight-line movement will be pulled towards the gravity well of the gas giant.

Yes, it explicitly says that ships are affected by gravity, both the short snippet I quoted and the whole section you quoted. Note that the gravitational pull is added to manoeuvre acceleration and aerobraking, so the ship need not travel in a straight line or outside the atmosphere for this to apply.

Conclusion: AG drives, or thruster plates, or chemical rockets would all fit within the same parameters for movement.

If we had a AG or CG drive we could turn it on to counteract the gravitational pull or possibly provide extra acceleration, but we apparently can't. The only conclusion I can reach is that we don't generally have AG/CG.

Earlier you stated that you consider CG to 'nullify' gravity, have you changed your mind? If gravity is nullified how can it accelerate the ship?

Further conclusion - nothing you said is germane to the discussion. At no point has anyone, but you, tried to interject movement of ships in space and equate them with movement of ships trying to take off or land.

Gravity works the same in space as in atmosphere. Newtonian mechanics work the same in space and in atmosphere, we just have to add some aerodynamic forces.

I don't understand your argument: Do you really believe basic physics, such as gravity, change completely when you leave the atmosphere?

Streamlined Hull: A ship designed to fly through atmosphere – will feature a wing or lifting body.
...
A streamlined ship is designed to enter a planetary atmosphere, and can function like a conventional aircraft. ...

As usual, you have neglected the other quotations provided on lifting bodies. In all the research done on lifting bodies, none of the experimental craft took off from the ground. In fact, if you look at the origin of lifting bodies, they were designed for controlled descents from orbit. And all of the experiments involved the lifting body craft being carried aloft by a B-52 and dropped.

That is not my opinion, that is an explicit rule.

Are you arguing that aircraft can't fly, or that some specific starship illustrations are not developed in a windtunnel by professional aerospace engineers?

I will of course not accept that the aerodynamic properties of e.g. the X-24 makes it impossible for all spacecraft to fly in all atmospheres and all gravities.

If you consider that some specific spacecraft needs bigger or better wings, just say so.

Any climbing was done via their rocket engines. I can put a rocket engine on a brick and it can gain altitude. Doesn't mean it is flying or generating enough lift on it's own.

And by some strange coincidence most spacecraft has a big, fat thrust generating device at the rear.

I also note that all fixed-wing aircraft needs thrust supplied by the drive to climb, or even maintain speed and altitude, except possibly in the case of thermal upwinds.

I believe no one, including yourself, is going to argue the brick is capable of flying.

No, and neither is it a streamlined spacecraft. So?

What does this have to do with a streamlined spacecraft with carefully designed aerodynamic surfaces at stellar tech level?

Per your quotes above, ships are able to fly so long as they have power. Flying implies forward movement. Lift requires a great deal of forward movement, the more mass an object has the more more forward movement and lifting surfaces are required.

Yes, obviously.

If you want to say that all of that is combined that's certainly your perogative. But a far simpler explanation that uses common sense is that CG lifters are present and simply not detailed.

I don't understand your argument.
Are you suggesting that aerodynamic lift does not exist, or can't possibly generate enough lift to keep a 5000 tonne spacecraft aloft?
Are you suggesting that thrust does not exist, or can't possibly accelerate a spacecraft away from a planet?
Are you suggesting that all forces acting on the aircraft should not be added together to determine how the aircraft will move?

Take an aircraft climbing at a 45° angle. Lift is normal to airflow, so a force pointing up and rear at a 45° angle. Drag is a force pointing down and rear at 45° angle. Thrust (unvectored) is a force pointing up and forward at a 45° angle. Gravity is a force pointing straight down. Will the aircraft accelerate or decelerate? Are you suggesting that the lift, drag, and thrust vectors should not be added to see if the aircraft can overcome gravity?

No, it's really not. Do we know how much the windows on the bridge cost? No. Do we know if you add a crapper in the ship it costs X more credits? Nope. I don't think the rules actually state how much an extra crapper is going to be.

I know you are joking, but T5 actually do cost "crappers", eh, freshers.

We obviously don't know that the windows cost, but we do know that AG drives cost significant space, money, and power.

You, again, fail to see reason.

Your opinion is not the definition of reason.

A starship hull has a multitude of equipment, items and fittings on it. Not everything is listed. For example - landing gear isn't mentioned. It's cost is assumed to be included. ...
In the systems that specifically call these items out (such as GURPS), they are specifically listed in the ship descriptions for those that would have them.

Yes, in the design systems that include AG/CG, they have a significant cost. There is no reason to assume that they are suddenly very cheap.

As far as grav equipment being more expensive than ground craft, duh? A BMW is more expense than an Opel, no?

Silly argument. Heavy ground craft cost kCr 3 per space, heavy grav vehicles cost kCr 80 per space. This is more like the difference between a car and a helicopter, than the difference between mass market cars.

Grav vehicles are the top end of vehicles, and as such it is only common sense that they would be more expensive than ground craft. Isn't that a logical and obvious conclusion ... ?

An air/raft is a basic truck, not a luxury vehicle, a GCarrier is a para-military transport not a luxury vehicle, yet they still cost something like 25 times the corresponding ground vehicle.

I would call your argument grasping at straws.

Or you just say "Spacecraft have vectored thrust", no extra cost, complication, or systems required. As specified in MT and Gurps.

Your statement is incorrect. Per the rules you have cited, for that to work the ships would have to overdrive their maneuvering systems to generate sufficient lift.

In MT, but not in Gurps. You don't have to choose the most complicated system to import from an earlier editions.

And even per SSOM, a 1.1G planetary gravity would make it impossible for a ship with 1G drives to take off, ...

Yes, agreed, as I have said a few times.

Unless you have wings or other aerodynamic lift, as streamlined spacecraft have according to MgT rules.

 

[Old School]

So I haven’t been following all the back and forth, but I thought it might be helpful for ya’ll to explain this terms of an example.

I have attached a picture of an Imperial Treasure Ship, which is a 1600 ton, 1G capable ship opersted by the Imperial Navy. In the Pirates of Drinax adventure “Treasure Ship”, this ship lands and later departs from the downport on Acrid under its own power. Acrid is a size A, 1.4 G world, with a violent atmosphere that requires atmospheric weather control to allow ships to land safely.

Can each of you involved in this debate explain the process by which this ship lands and takes off?

Sure. Per my view, starships have an integral counter-grav capability that allows them to land and take off from planets and other gravity wells. The counter-grav nullifies gravities pull on the ship, allowing it to ascend, hover or descend. The ships thrusters are used to spin or change angle of attack. They operate the same as they would in zero-G - thus while the gravity well pull is nullified, the ship still has mass, just as it would in a zero-g environment. So movements are what you would expect from maneuvering thrusters, for each burn clockwise, an equal burn is required in the opposite direction to halt the movement. Which can be easily handled via manual or computer control.

Once the ship has obtained the necessary altitude the main engines, or even thrusters, are used to begin maneuvering it away from it's docking location. So if the ship was in a standard downport docking facility/warehouse, it would either ascend up through a retracted roof or back out the hangar door assuming it pulled in like a conventional garage. At some starports it may need to taxi away from the docking area to reach the designated area to begin it's ascent (much like a plane does on a taxi way). Other places it could vertically ascend to a height, then fire off it's main drive to begin the trip to orbit. In any case it's still subject to normal aerodynamic issues, such as wind shear, turbulence, etc. Once it's drive is fully functioning it may turn off it's CG for lifting. In the case of a 1.4G world and a 1G ship, and in this case ,the shape of the ship, I would assume the ship would require the extra lift from the CG system until it had reached a high enough velocity or the pull of gravity was less than the ability of the ship's drive to maneuver.

Thanks. Makes total sense to me. I’m not sure what other scenario would.

 

[AnotherDilbert]

I have attached a picture of an Imperial Treasure Ship, which is a 1600 ton, 1G capable ship opersted by the Imperial Navy. In the Pirates of Drinax adventure “Treasure Ship”, this ship lands and later departs from the downport on Acrid under its own power. Acrid is a size A, 1.4 G world, with a violent atmosphere that requires atmospheric weather control to allow ships to land safely.

Can each of you involved in this debate explain the process by which this ship lands and takes off?

I would say that it normally couldn't, but phavoc mentioned that repulsor beams could assist too heavy craft on some starports?

 

[Old School]

The person who wrote that adventure also wrote the 1st edition Mongoose rules, and he obviously thinks it can. I think you’re spinning yourself in circles around something not being specifically mentioned in what is intended as a light ruleset. The OTU clearly intends far traders and fat traders to being able to utilize frontier quality downports. If they were incapable of taking off from hogh gravity worlds, certainly this would be mentioned somewhere? Its kind of a big deal.

Since neither anti-grav lifters (such as T5) or the major functional limitation resulting from the lack of same is me tioned, we have to go with the one that makes sense and fits the setting as described. I don’t understand why the answer isn’t apparent to anyone who has played the game, but so be it. I’m moving on.

 

[Old School]

The person who wrote that adventure also wrote the 1st edition Mongoose rules, and he obviously thinks it can. I think you’re spinning yourself in circles around something not being specifically mentioned in what is intended as a light ruleset. The OTU clearly intends far traders and fat traders to being able to utilize frontier quality downports. If they were incapable of taking off from hogh gravity worlds, certainly this would be mentioned somewhere? Its kind of a big deal.

Since neither anti-grav lifters (such as T5) or the major functional limitation resulting from the lack of same is mentioned, we have to go with the one that makes sense and fits the setting as described. I don’t understand why the answer isn’t apparent to anyone who has played the game, but so be it. I’m moving on.

 

[AnotherDilbert]

In space, zero-G, gravity is nullifed. Amazingly enough you can still nullify gravity in orbit and stay attracted to a planetary body. Using your analogy above the ISS should be left behind as the planet (and star) accelerate away from it. So I guess the ISS is violating the space-time curvature?

You are describing free-fall, not absence of gravity.

The IIS is in orbit around the Earth, since it is very much affected by gravity. The passengers of the IIS experience free-fall since both the station and the people in it are falling freely towards the Earth. Since they are all falling at the same rate (acceleration, cf Galileo) they are not pressing against each other and experience no acceleration through contact. Or if you wish, they are moving straight forward in curved space time.

See the Principle of Equivalence (or Einstein's Monkey). https://en.wikipedia.org/wiki/Equivalence_principle

What we experience as gravity is the solid object we are standing on preventing us from falling. What's lacking in orbit is not gravity, but the solid object.

The velocity of the IIS is carefully chosen so that it moves forward as quickly as it falls downward, so that it moves in a rough circle around the Earth. You can't be in orbit unless you are affected by gravity.

An air/raft that tried free-fall would hit the ground, unless it moved quickly enough to burn up, and they would certainly not need any drive system to do it...


Edit: In a hope that wiki can explain better than me:

https://en.wikipedia.org/wiki/Free_fall

In a uniform gravitational field, in the absence of any other forces, gravitation acts on each part of the body equally and this is weightlessness, a condition that also occurs when the gravitational field is zero

Sorry, can't add more links: en.wikipedia.org/wiki/Weightlessness

Weightlessness is the complete or near complete absence of the sensation of weight. This is also termed zero-g, although the term is more correctly "zero g-force." It occurs in the absence of any contact forces upon objects including the human body.

Nope. Check the dictionary again. You want to be specious and play word games with definitions. But it's not germane to the discussion.

You started the word games. I'm happy leave it out.

You are magically ignoring we have objects orbiting our planet, in zero-g, that remain in place. Or do you want to say those objects in space orbiting our planet are violating simple Newtonian physics? They either are, or they are not.

If they are in orbit they are very much affected by gravity and obey Newton and general relativity, as explained above.

If they were not affected by gravity they would not be in orbit, but continue straight forward as the planet accelerated away in its orbit.

https://en.wikipedia.org/wiki/Orbit

In physics, an orbit is the gravitationally curved trajectory of an object, such as the trajectory of a planet around a star or a natural satellite around a planet.

Again a big, fat nope. All anti-grav/contragrav is doing is replicating the effect an object in space has closer to the surface of a planet.

Free fall, splat... It would be brief...

First law: In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force.
Second law: In an inertial frame of reference, the vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration a of the object: F = ma. (It is assumed here that the mass m is constant.)
Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.

And what do you think the term m is in F=ma? Newton's first is just the special case where F=0, hence 0=ma, hence a=0

However if you look at my statement I said "mass is never ignored, but can be countered". Antigravity, as you so pointed out, is countering it.

AG might change weight (gravity's effect on mass) never mass or inertia.

Meaning a tonne of steel is as difficult to move in the absence of gravity as on the surface of the Earth (if we place it on a hypothetical frictionless plane).

Again, non-sequitur argument.

If you consider basic physics irrelevant, sure.

My speculation about Newton is in reference to your continued desire to drag it in and bring up an obtuse, non-sequitur argument. You have studiously ignored all other physical laws but his even though it has been pointed out time and again you cannot use just his laws.

I keep bringing it up, because it seems you want to ignore it. When you want to accelerate away from a planet it's kind of important.

I have repeatedly stated that we need both lift (aerodynamics) and thrust (Newton) to see if we can escape a gravity well with wings. I believe that is incompatible with "studiously ignored all other physical laws".

Since we both believe the other is trying to ignore something, we are probably misunderstanding each other fundamentally.

And, by definition, a rocket generates zero lift.

Agreed.

Vectored thrust is not mentioned in MgT as far as I know. Where in MgT is it stated that ships generally use contra-grav? Or even contra-grav at all?

Neither is mentioned. Therefore we both must be wrong.

Agreed, neither is mentioned. I would say that makes them both equally far-fetched, so we can't use this criterion to choose between our hypotheses.

What cost? According to MGTv1 CRB, a standard hull (a wedge, cone, sphere or cylinder), "A standard-hull ship may still enter atmosphere but is very ungainly and ponderous, capable only of making a controlled glide to the surface. Getting it back into space requires an elaborate launch setup and considerable expense." By the rules both of us, again, appear to be wrong. Or else the rules are wrong.

I don't understand; if it can't lift, it can't be presumed to have AG, so has no bearing on the cost of AG?

Agreed, it is A lifting force, but it is not the only possible lifting force. E.g. thrust from the M-drive or AG can also be used as a lifting force by pointing it in the opposite direction of gravitational pull.

Yeah, according to the definition it is - https://en.wikipedia.org/wiki/Lift_(force)

We are talking in circles. I have no idea what the basic misunderstanding is.

What do you call thrust that is applied so that a craft is accelerating away from the planet? I called that "a lifting force" specifically to separate it from aerodynamic lift.

As far as I know we agree that rockets can reach space using thrust alone?

You realize that that would make CG craft useless too?

However, all contra-grav vehicles are assumed to have vectored thrust agencies to hold up the remaining fraction of their weight, allowing them to hover.

Nope, didn't ignore it. Analyze that statement. It violates even the book definition of what anti-gravity is.

It agrees perfectly with my idea of contra-grav (not anti-grav), and the definition in TNE.

AG/CG does not repeal gravity, if just applies thrust to the craft, In the case of CG the thrust is always ≤ the force imposed by gravity.

Nice strawman you got there... Showing that vectored thrust is possible by example does not mean that all aircraft have it nor that all aircraft are identical.

Strawman how? I took your explanation and added in the facts. You cited the Harrier as an example of a craft with vectored thrust and it can take off. I proved the other part of the equation in that it cannot do so fully loaded. That's not a strawman. It's an inconvenient fact for you.

I repeat: "Showing that vectored thrust is possible by example does not mean that all aircraft have it nor that all aircraft are identical."

The Harrier says nothing specific about any other aircraft, it just says that take off with thrust alone is possible, hence lift is not the only possible way to take off.

MgT clearly state that streamlined ships, like the Subbie, fly like aircraft.

Whereas in MT drives needed to be overdriven, and were able to be overdriven, that was apparently not necessary in Gurps (nor in TNE or T5). As I believe we agreed, details differ between editions.

You forgot that you quoted how the game is supposed to be an extrapolation of current physics? You forgot that in reality the lifting body aircraft were never capable of taking off, just making controlled descents?

I don't understand your argument.
I argued that ships with wings can fly, you answer that ships without wings can't fly. What does that have to do with it?

That specific craft (the X-24) could not take off, that does not mean that all possible lifting body craft are unable to take off thousands of years into the future.

A specific example can show that something is possible, it can never show that something is impossible.

You forget the definition of lift that has been provided multiple times (and even quotes from the boys at NASA? You forget the section of GURPS starships I quoted word for word that covered whether or not a ship could actually fly using its hull as a lifting body?

No, I have even quoted them myself. Again I don't understand your argument.

Lift is the aerodynamic force perpendicular to the airflow and Gurps state that we add M-drive thrust, CG thrust, and lift to determine if a spacecraft can take off.

In what way does that make the Subbie, or any other hypothetical spacecraft, unable to take off?

Have you ever done maintenance on a vehicle that is run at 110% at all times?

We were discussing overdriving the M-drive a few minutes every month. That is rather far from always.

And we have no idea what kind of wear-and-tear that inflicts on 53rd century M-drives.

No, he was an actual man. Evidently if someone says something you don't like it's a strawman. Gotcha.

I said ""Spacecraft have vectored thrust", no extra cost, complication, or systems required. "
You said "Your assumptions are far more complex than mine, and have to span multiple rule sets in an attempt to justify them."
I call that a strawman.

I would obviously not suggest that we use the incompatible systems in MT, Gurps, and MgT at the same time, any more than I believe you would suggest that we use the incompatible AG/CG systems in MT, Gurps, and MgT at the same time.

I merely suggest that we can use other editions to fill in details that are glossed over in the current edition, but fleshed out in earlier editions. And that of course goes for M-drives and AG both.

You cannot take the specifications from one rule system and apply them to the other without also taking the limitations. And you continue to ignore the limitation rules for MGT on overdrive.

I didn't. I suggested that we take one system with limitations and all, not all of them at once.

Agreed, yes, generally, but the Subbie has wings so can add lift to the equation.

And they also add drag, canceling out the lift.

You are guessing. Obtain a 53rd century spacecraft, put it into a windtunnel and I will believe you.

I would suggest we use one system at a time, either MT with 25% lateral thrust and 400% overdrive, Gurps ( and perhaps TNE and T5) 100% lateral thrust and no overdrive, or perhaps 50% lateral thrust and 100% overdrive in MgT2?

Overloading the drive is a difficult (10+) roll. It only increases thrust for one round. There is a cumulative effect (-2 on your roll) EACH time it is attempted. The attempt will increase the drive thrust by 1. This penalty may be removed by performing additional maintenance on the drive for 1D hours. That's extra work just to take off or land. If you reference SSOM you only get 25% lateral thrust. It seems to me that the risk of getting a critical hit to the drive each time you take off or land should never be considered normal.

Ok, you want to conflate the MT and the MgT system.

We can just as well the Gurps system, which you seemed to like earlier, without any overdrive or rolls.
Or the SSOM system with overload, but no rolls.

 

[AnotherDilbert]

I think you’re spinning yourself in circles around something not being specifically mentioned in what is intended as a light ruleset. The OTU clearly intends far traders and fat traders to being able to utilize frontier quality downports. If they were incapable of taking off from hogh gravity worlds, certainly this would be mentioned somewhere? Its kind of a big deal.

You assume all ships can land everywhere, I assume the movement system described in LBB2 meant what it said.

I find that it adds interesting texture to the terrain if all ship can't go everywhere. The Scout can land where a Free Trader can't: Good! You might need small craft to land where your ship can't: Good!

Note that small merchants going to lesser starports means only unrefined fuel is available, so you have to roll for misjump by CT RAW. Not being able to land on a few planets is the least of your problems.

I don't see any problem with the way I have played the game for decades, and you obviously don't see any problem with the way you play. Good for us both.

But saying that your assumption is the only one that makes sense and should be apparent to anyone is a bit narrowminded. I would of course answer that my assumption is the only one that makes sense and should be apparent to anyone...

 

[Anonymous]

I don't think mixing Traveller editions is a good idea. It will just confuse things. If play Mongoose I don't really care what T5 says, and the reverse. If people want to say T5 is canon in non-T5 games because its MWM, well if they buy it for me and fix everything that it breaks (good luck), I'll go with it.