Streamlined Vs. Partially Streamlined

[BetterThanLife]

Originally posted by Aramis:
Again, Bhoins, FF&S is the terminology standard. It ain't "CG" principles, it is "gravitic thruster"; I nitpick on this one, as it's one that got missed in the playtest. (Vehicle design was much later in the sequneces. Many of us were showing burnout...)

gravitic thrust, as expressed in TNE and T4, is very different from contra-gravity. One generates thrust by means of gravitic theory; the other disconnects one from local gravity.

different paradigms entirely.

Yes, it's a nitpick. No, they are not mutually exclusive, but they are clearly NOT the same. CG CAN'T produce thrust other than by buoyancy, which will always be purely up/down.


But yes, I agree that the idea of CG is not explicitly DENIED in T20, nor is it implicitly included as a standard.

GRavitic thrust, however, is implicitly there. A different but possibly related technology.

I guess we were discussing the same thing using different terms. So in your terminology what keeps an air/raft airborne and allows it to climb and dive? I was under the impression it was a technology that pushed against the local gravity providing thrust. Not the same as using gravitic technology to produce thrust when outside a gravity well. (Thruster Plates) The second always bothered me more than the first. Gravity obviously exerts a force. If you could produce a device that produces a force that pushes against this force then you have a contragravity device. A Parallel technology would be to create artificial Gravity wells in space to propell a ship. Exactly how this might work is beyond my limited physics education but I would suggest that thruster plates is less likely than David Weber's Impeller Drives.

If you are pushing back against gravitic force there is no reason that you would be limited to the amount of force that is being applied to pull your craft to the ground and therefore could generate lift and climb as opposed to just floating because you have neutral bouyancy. That technology would far outstrip the limited capabilities of lifting surfaces. (Mostly in that they break down at certain speeds, have a rather narrow operating range and actually require a hospitible atmosphere to work. In return these lifting surfaces add to drag and require more thrust than would otherwise be required for a similar size and shaped craft to go the same distance at the same speed.

That was my point. Air/Rafts obviously, in Traveller, work. Starships obviously land and take off vertically and usually perpendicular to the plane of thrust. Speed of a craft is not dependent on the size or density (hence gravitic force exerted by the planet) of the planet you are on, which implies an engine for thrust and forward speed and something else to generate lift. And these lifting technologies are not dependent of an atmosphere or, unlike an airfoil, a forward speed.

Since this gravitic lift is independent of forward motion and atmosphere, this technology is clearly superior to aerodynamic lift for starships, or any other craft for that matter. Further forward thrust, by its nature is a different technology than the technology providing lift as it is produced in a direction as much as 90 degrees off the direction of gravitic force so can't be pushing against this force.However this technology would work well to generate gravity aboard a starship. And if gravitic shielding can be developed then a ship could sit on the ground without need to be concerned with which direction is down. However no canon ships demonstrate this capability. (Ie they don't land with the deck floors in a direction other than what is down when you are on the planet.) For example the Beowulf landing tail down. THough there is a picture of a Guardian class SDB being Tail down on a launching pad so maybe this tech does exist.

 

[aramis]

Contra-grav is defined in Traveller contexts (FF&S 1 &2) as a very specific thing, and it isn't a thrust agency.

Gravitic thrust exists in all but one edition of traveller; TNE Air rafts use CG to negate most gravity, and are purely a heplar-lifted and flown item.

Most T4 grav vehicles likewise do not use gravitic technology for thrust, either, also relying upon HEPlaR and CG in combo.

Making them a very different beastie from the CT, MT and T20 air rafts.

 

[BetterThanLife]

It appears we have been discussing different gravitic theories and thinking we were discussing the same thing from different angles.

Well since I have never played either TNE or T4. (In point of fact I had never heard of T4 until I bought T20 and started frequenting this board.

I wouldn't know that distinction.

I do know that in CT, MT and T20, Contra Gravity, or whatever you want to call it provides lift. (Call it Anti-Grav to avoid confusion?) Or something else does but it is not related to the thrust of the craft. (Or accelleration would be dependent on gravity of the world and ships wouldn't have to turn over.

So the question still remains, why would a craft, such as a sphere or cylinder which in T20, CT or MT does not require lifting surfaces, be considered not streamlined enough to land, in an atmosphere when it is one of the more efficeint, in terms of drag, aerodynamic shapes? (After all most balls are round, bullets started round and then went to pointed cylinders.)

Originally posted by Aramis:
Contra-grav is defined in Traveller contexts (FF&S 1 &2) as a very specific thing, and it isn't a thrust agency.

Gravitic thrust exists in all but one edition of traveller; TNE Air rafts use CG to negate most gravity, and are purely a heplar-lifted and flown item.

Most T4 grav vehicles likewise do not use gravitic technology for thrust, either, also relying upon HEPlaR and CG in combo.

Making them a very different beastie from the CT, MT and T20 air rafts.

 

[Andrew Boulton]

"TNE Air rafts use CG to negate most gravity, and are purely a heplar-lifted and flown item."

I've never been happy with the idea of grav vehicles flying round cities squirting plasma everywhere...

"Most T4 grav vehicles likewise do not use gravitic technology for thrust, either, also relying upon HEPlaR and CG in combo."

T4 CG allows you to use a fraction of the lift as thrust.

 

[BetterThanLife]

Apparently each version has its own problems with technology. If I didn't have Gravitic lift and reactionless thrusters but could negate 98% of the weight then, in an atmosphere, I would use a flyby wire system, and electric turbofans, providing both thrust and lift. And using VIFFing for maneuverability. (With a fuel cell or fusion powerplant.) Clean air but a crash that ruptured the fusion bottle could get messy.

Originally posted by Andrew Boulton:
"TNE Air rafts use CG to negate most gravity, and are purely a heplar-lifted and flown item."

I've never been happy with the idea of grav vehicles flying round cities squirting plasma everywhere...

"Most T4 grav vehicles likewise do not use gravitic technology for thrust, either, also relying upon HEPlaR and CG in combo."

T4 CG allows you to use a fraction of the lift as thrust.

 

[aramis]

FF&S 2 has gravitic thrusters, too, and not just FF&S1 style CG. Then again, T4 has 4 different craft design rulesets, of varying compatibility with each other and the rest of traveller.

(QSDS, SSDS, EmpVeh, and FF&S2)

 

[Andrew Boulton]

Thruster plates are in FF&S1, under Alternative Technologies.

 

[BetterThanLife]

Thinking about it, there is still no reason to include lifting surfaces. Since it would require very little thrust to provide lift, and since thrust would be independent of atmospheric density (or lack there of) or composition it would make more sense than lifting surfaces to provide lift.

 

[aramis]

Andrew: its specifically not "OTU" in TNE to use T-plates. Doesn't matter what was in the alternate tech options.

WHy? becuase the TNE-OTU made some drastic changes to HOW things operated.

Bhoins: economically, if you ever needs the lifting surfaces in the life of the ship, it's worth the additional cost. ONE engine-off landing pays for the lost revenue over the mortgage lifespan.

In TNE, ships carry hours of maneuver fuels; often less than 10 hours... at fuel rates of more than 1% tonnage per hour; the savings in fuel costs add up, and further mitigate the costs. Further, it allows use of far less fuel should one need to transit port-to-port. Coupled with TNE CG, 0.05G could provide lift sufficient to fly.

also, TNE defines airframe in FF&S to mean aerodynamically lifted designs (Including both rotary and fixed wing).

T20's use was taken DIRECTLY from FF&S. (I know because I am the one who put the idea of airframes forward to hunter. We talked in FF&S terms quite a bit during the playtest.)

90% of major population should be on habitable worlds. that it isn't is an artifact of space opera. When one looks at post-collapse, say hard times or TNE, most of the population is on habitable worlds; those worlds, and many more, have atmospheres.

 

[BetterThanLife]

While it may be the case in TNE and 1248 that most human habitation is on planets with a breathable atmosphere. It is clearly not the case in the 990s (Gateway to Destiny/Solomani Rim War era.) or the early 1100s, (Traditional CT campaign through the time before Virus and civilization collapse.)

Airframe definition existed before TNE and FF&S. MT had an Airframe option for starships but it doesn't specify lifting surfaces. T20 includes Airframe but does not state that includes lifting surfaces though it does include control surfaces.

CT LBB2 and LBB5 don't have Airframe defined. So we have 3 versions that don't say you need lifting surfaces and one or 2 that say Airframe require lifting surfaces. (THough I haven't read either of them so I don't know what they say.)

I do definitely know, from reading the rules in T20 that T20 Starship design owe more to LBB5 than any other version of Traveller. Except for sensors virtually everything in Starship design comes directly from LBB5. There are definite differences, however the basis is LBB5. So given the obvious lack of lifting surfaces on most canon ships and the lack usuable atmosphere on many high tech, high pop worlds, lifting surfaces do not define an Airframe. Even today lifting surfaces are not required on an airframe. A CH53 body is an airframe but has no lifting surfaces. With definite technological advances, the major one being the introduction of the air/raft-grav vehicle, there is no longer any reason for lifting surfaces in an airframe. Lifting surfaces cause as many problems as they solve. And if they weren't required for economic long distance flight they would be removed. The air/raft, which functions in all versions of Traveller, shows that you don't need wings or lifting surfaces for economic flight. So if on planet travel doesn't require lifting surfaces to work, why should starships, which spend the majority of their time outside atmospheres, want lifting surfaces.

Lifting surfaces are not required for an airframe nor is everything with lifting surfaces an airframe. In all actuality not everything with functional wings is an airframe.

Originally posted by Aramis:
Andrew: its specifically not "OTU" in TNE to use T-plates. Doesn't matter what was in the alternate tech options.

WHy? becuase the TNE-OTU made some drastic changes to HOW things operated.

Bhoins: economically, if you ever needs the lifting surfaces in the life of the ship, it's worth the additional cost. ONE engine-off landing pays for the lost revenue over the mortgage lifespan.

In TNE, ships carry hours of maneuver fuels; often less than 10 hours... at fuel rates of more than 1% tonnage per hour; the savings in fuel costs add up, and further mitigate the costs. Further, it allows use of far less fuel should one need to transit port-to-port. Coupled with TNE CG, 0.05G could provide lift sufficient to fly.

also, TNE defines airframe in FF&S to mean aerodynamically lifted designs (Including both rotary and fixed wing).

T20's use was taken DIRECTLY from FF&S. (I know because I am the one who put the idea of airframes forward to hunter. We talked in FF&S terms quite a bit during the playtest.)

90% of major population should be on habitable worlds. that it isn't is an artifact of space opera. When one looks at post-collapse, say hard times or TNE, most of the population is on habitable worlds; those worlds, and many more, have atmospheres.

 

[BetterThanLife]

Taking it one step further. What is the most efficeint powerplant under FF&S? If FF&S is the same as the rest of Traveller it should be a fusion plant. In that case, instead of using a polluting, fuel burning maneuver drive in an atmosphere why not use turbofans. They can be electrically driven and therefore use little fuel and can easily supply enough lift to cancel out the remaining 2% of mass that FF&S CG doesn't cancel out.

 

[jhulse]

Give me contra grav and thruster plates and I can make a dumptruck enter and exit orbit with out any problems.
Well... give me a space suite while I sit in the dumptruck, THEN I wouldn't have any problems.

 

[aramis]

TNE/T4 FUsion plants are hyper-efficient compared to other traveller editions: worst fusion is 0.75 KL fuel per KL of plant per year. yes, per year.

Antimatter takes over at TL 17, an order of magnitude better power output for similar fuel rates.

ANd Heplar can be run off ANY PP; fuel cells are efficient enough at TL 12 to run them.

 

[BetterThanLife]

Then once you hit atmosphere electric Turbofans or something similar and ultra techy, are definitely the way to go.

Originally posted by Aramis:
TNE/T4 FUsion plants are hyper-efficient compared to other traveller editions: worst fusion is 0.75 KL fuel per KL of plant per year. yes, per year.

Antimatter takes over at TL 17, an order of magnitude better power output for similar fuel rates.

ANd Heplar can be run off ANY PP; fuel cells are efficient enough at TL 12 to run them.

 

[aramis]

The problem is that FF&S was well thought out, but the stock designs weren't.

Same thing for T20.

 

[BetterThanLife]

But all this doesn't answer the basic question, "why the Broadsword, because it is a sphere, shouldn't be able to land on a planet?"

 

[aramis]

The Broadsword should be able to; she's shown as a sphere SL... if the UPP doesn't then the UPP is a different variant!

Simple enough?

 

[BetterThanLife]

Should be. And I agree that a Sphere should be capable of landing on the surface. However, a Sphere in LBB5 can't land, though it can in MT. (Funny, I missed that in MT until just now, I guess I was too hung up on LBB5 to realize it was a change.

Interesting! ) And you have to upgrade it in T20. (Though in T20 you can actually upgrade it.)

So I guess it is even simpler. It is only in CT where you couldn't land the Broadsword even though it is clearly designed for landing.

Looks, like the new campaign is going to be a Mercenary campaign, thought I should dig out the old deckplans.

 

[aramis]

It's only in CT USING Bk5 that you can't.
Under Bk2, you could. And, since you were officially allowed to mix-n-match Bks 5 & 2...

 

[BetterThanLife]

Well since I am using T20 for the campaign I can land a Broadsword. Once we get to that point, and no I don't start parties with a Broadsword, I see no reason not to allow it to land.