Hazards of frontier refuelling

Discuss the Traveller RPG and its many settings
AnotherDilbert
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Re: Hazards of frontier refuelling

Postby AnotherDilbert » Fri Aug 09, 2019 10:30 pm

Old School wrote: p. 155 is directly contradicted by P. 106, which states that Only INT and EDU-based checks can be attempted.
I see no contradiction.
Core, p106, Expert:
Expert software packages mimic skills. A Traveller using Expert may make a skill check as if he had the skill at the software’s Bandwidth -1. Only INT and EDU-based checks can be attempted. If a Traveller already has the skill, then Expert grants DM+1 to his check.
A Traveller, or I assume sophonts in general, can only use Expert software as a replacement for INT and EDU skills.

The same is not true for Intellect software or robots, see CSC p68 and p71 (Astro-Mech Droid with Pilot skill but no hands).
CSC, p68, Intellect:
An Intellect software package is similar to the more primitive Agent but has a far more advanced intelligence, being able to communicate normally with a Traveller. It is capable of using any Expert package and can simultaneously use a number of Expert packages equal to its Bandwidth.
This is completely consistent with Core, p155, as far as I can see:
Core, p155, Automated Duties:
A ship running an Intellect program and Expert Pilot can act as the pilot.

Old School wrote: Your house rule for allowing expert software to augment DEX based tasks but not perform them unskilled is reasonable, but this goes against your next sentence that you would allow Expert 3 to fly the ship.
I do not consider that a house rule, but simply RAW. See e.g. Core, p107:
Core, p107, Expert Skills:
Having a tool or weapon with the appropriate Skill Expert program and an Intelligent Interface can grant a Traveller DM+1 to his checks.
Note that this explicitly applies to weapons, hence in general DEX-tasks.

I see the statement about Expert software this way:
Core, p106:
... A Traveller using Expert may make a skill check as if he had the skill at the software’s Bandwidth -1. Only INT and EDU-based checks can be attempted. [Line break added]

If a Traveller already has the skill, then Expert grants DM+1 to his check.
This is consistent with p107, in my opinion.

This interpretation makes all the rules about Expert software valid and consistent. Your interpretation seems to rely on that most of these rules are simply wrong.

I can agree that the rules are not intuitive or perfectly clear.
Old School
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Re: Hazards of frontier refuelling

Postby Old School » Fri Aug 09, 2019 11:38 pm

Some of your logic makes sense, but I do remember that in the past you had argued that skill checks and attacks rolls were not the same thing. You appear to be taking the (more reasonable) opposite approach now.

And I don’t see how the contradiction is not blatantly obvious. You have to jump through logical hoops to get around it. I admire your skill in doing so.
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Re: Hazards of frontier refuelling

Postby Moppy » Fri Aug 09, 2019 11:51 pm

The claim should be judged based on its content and not who it's from. To do so otherwise is to form a prejudiced judgement.
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Re: Hazards of frontier refuelling

Postby phavoc » Sat Aug 10, 2019 1:43 am

Moppy wrote:
Fri Aug 09, 2019 11:29 am
phavoc wrote:
Fri Aug 09, 2019 4:44 am
Aero control surfaces are subject to stress like any other object. To be effective they have to be thin and aerodynamic, which means they would be vulnerable to being snapped off in certain situations. If you made them armored and thick like the hull then they could no longer perform their function.
Sorry but I disageee strongly. Ailerons on a jetliner look like they're about 5cm (2") thick, which is thicker than hull on some armored vehicles.

edit: Haven't measured it personally but I've walked around aircraft before.

edit: OK, photo time. Apart from the very tip, it's well over 5cm (2") and it still flies even if the edge breaks off. They can break (there was the airbuses that lost rudders) but they're much thicker and stronger than you probably think they are.

Image
That actually appears to be flaperon, not an aileron. Aileron's are at the outermost portion of a wing. There are flaps to the left and right of it, the flaperon I mean. Thin-winged aircraft like the F014 also have very thin aileron's, but that is part and parcel of the design of the wing, which is very thin in order to avoid transonic drag. Later aircraft fixed this issue by sweeping the wings. Also most aircraft have thicker wing roots so that the bottom is flat and the top is rounded, to generate lift.

Traveller spacecraft are too heavy to use the same features. They also require actual wings to maneuver in such a way. I really don't know what "aero control" surfaces are supposed to mean in Traveller - they don't follow aerodynamic laws much. I suspect there's lots of hand wavium involved. Aero control surfaces still have to follow the rules of aerodynamics to work. Wings aren't control surfaces. "thin" of course, is also relative. Put it this way, most Traveller ships, especially player created ones are armored, some greatly so. An armored flap or aileron isn't going to be able to do both.

We could go down the rabbit hole or just accept the hand wavium and move forward.
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Re: Hazards of frontier refuelling

Postby Moppy » Sat Aug 10, 2019 2:44 am

phavoc wrote:
Sat Aug 10, 2019 1:43 am
That's a 747 as you can see the upper deck?

I don't think they have flaperons. I can't see it here. Looks to be just an inboard aileron as it's not down with the flaps. (edit: extended, not down. poor choice of words. whatever. not sure on exact technical term but it's clear these 2 control surfaces don't do the same thing).

Image

If lift was generated by a flat bottom wing with a curved top, how do planes fly upside down? This "curved top, flat bottom" is a common misconception of how wings work. You can google it if you want an explanation.

A-10 has armored control surfaces.

edit: Plane tech forum says the 747 has no flaperons. https://www.airliners.net/forum/viewtopic.php?t=728107
Last edited by Moppy on Sat Aug 10, 2019 3:39 am, edited 1 time in total.
phavoc
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Re: Hazards of frontier refuelling

Postby phavoc » Sat Aug 10, 2019 3:37 am

Umm, you posted an image of an Airbus first. Now you are posting an image of a 747. But let's run with that.

The image you posted comes from here - https://aviation.stackexchange.com/ques ... rd-aileron

If you scroll down a little below the image you will find this statement: "Airbus aircraft have no inboard ailerons because they move the flaps slightly differently: Whereas Boeing aircraft move them perpendicular to the hinge line, Airbus planes move them straight back. This avoids any interference between flaps on wing sections of different trailing edge sweep and the need for filling the gap with a flaperon. – Peter Kämpf May 9 '15 at 11:14 " The poster is saying the same thing I am, that is a flaperon, not an aileron.

This image from Quora is of a 747. You'll see that the aileron is at the end of the wings - https://www.quora.com/What-is-the-diffe ... -and-flaps. Scroll down and you will see the flaps fully deployed as well as the air brakes. To the best of my knowledge (and a limited search) 747 wings do not use flaperons.

Planes fly upside down due to thrust. The most efficient method of flying is right-side up due to the aforementioned flatter bottom, rounded top. You can go and complain to Bernoulli and conventional airfoil design. I'm just repeating what I learned. Wing design IS an actual science. Your airfoil depends a lot on how big, how fast/slow, how heavy, how much thrust you have and what you plan on doing with your aircraft. There are multiple versions out there, but the one I mentioned is pretty standard for nearly all passenger aircraft and large transports. Small civilian aircraft and military craft don't necessarily always follow the rule.

If you scroll down on this page - https://fas.org/man/dod-101/sys/ac/a-10.htm - you'll see a black and white image of the A-10 from different elevations. Notice the dual rudders in back. They are quite thin compared to the aircraft overall. The engines and portions of the flight control system are armored, though not as heavily as the cockpit. Over 1,000 lbs of titanium armor are there, but most of it is concentrated in a handful of areas. The craft has redundant hydraulic control system which help protect against damage, and a backup mechanical system. One of the primary systems it was designed to survive was the ZSU-23-4, which fires 4 23mm guns. A very effective ground system, but the A-10 could take (some) punishment from it and get away. You have to remember this was a 70s plane built to replace the Skyraider - and be relatively cheap.

Oh, and since ailerons are being discussed, the A-10 has massive ones, taking up like half the wing surface.
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Re: Hazards of frontier refuelling

Postby Moppy » Sat Aug 10, 2019 4:08 am

phavoc wrote:
Sat Aug 10, 2019 3:37 am
If the first picture is an Airbus and not a 747 then why's it got a half-length upper deck at the top right of the picture? Which Airbus is it?

If we agree 747s have no flaperons, I'm OK.

I do wish people wouldn't keep repeating that the wing generates lift because of a curved upper surface vs a flat lower. It's really badly flawed due to inverted flight - and it's hilariously obvious because everyone has probably seen planes fly inverted. More correct to say that it's one of the contributing factors.

I've never seen an A-10 up close, so I'm not going to comment on how its control surfaces move.

edit: Logic dictates that the majority of the lift must come from the wing being tilted slightly upwards. Certainly this must exceed the "curved airfoil" component to enable inverted flight.
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Re: Hazards of frontier refuelling

Postby AnotherDilbert » Sat Aug 10, 2019 10:47 am

Old School wrote: Some of your logic makes sense, but I do remember that in the past you had argued that skill checks and attacks rolls were not the same thing. You appear to be taking the (more reasonable) opposite approach now.
Since I don't remember what you are referring to, can you remind me?

An Attack is an action that is generally resolved with a skill check, but sometimes not. E.g.:
Core, Space Combat, p156, Firing Weapons wrote:The standard skill check used when making an attack from a spacecraft are as follows.
2D + Gunner (appropriate speciality) + DEX DM
Core, Space Combat, p162, Missiles and Targets wrote:When a missile salvo reaches its target, the missile makes an attack roll as normal. However, the Gunner skill of the Traveller(s) that fired the salvo is not used as a DM.
DMs that apply to Attacks do not necessarily apply to all skill checks. E.g.:
Core, Space Combat, p156, Common Modifiers to Spacecraft Attacks wrote: The following modifiers are commonly used to influence Gunner checks when attacking.
Note the DMs are only used for skill checks with the Gunner skill when attacking, not on all skill checks.


Old School wrote: And I don’t see how the contradiction is not blatantly obvious.
The contradiction disappears if we can agree that computers and people use Expert software differently. A computer can use actuators directly, whereas humans have to turn a wheel or joystick to make something happen.

Let's take driving a car for example: A computer controlling the car can turn the steering wheels by controlling the servo, but an unskilled human would have to turn the steering wheel after the computer says "Turn Left" which would be clearly impractical.

Note that unskilled humans can use a Neural Link (CSC, p91) to allow the computer to control his body, and hence gain the use of physical skills from Expert software.
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Re: Hazards of frontier refuelling

Postby AnotherDilbert » Sat Aug 10, 2019 11:30 am

Moppy wrote: edit: Logic dictates that the majority of the lift must come from the wing being tilted slightly upwards. Certainly this must exceed the "curved airfoil" component to enable inverted flight.
Yes, lift varies with angle of attack:
https://en.wikipedia.org/wiki/Angle_of_ ... k_and_lift
Example:
Image
In this example we would presumably get negative lift at less than -5° AoA, and be able to fly upside down at perhaps -10° AoA or so.


But I believe this increased lift comes at a cost of greatly increased drag, hence needed thrust.
https://www.grc.nasa.gov/www/k-12/airplane/inclind.html
Example:
Image


So, to minimise needed thrust and hence fuel consumption and/or speed, in level flight airplanes generally strive to keep angle of attack low and rely on the pressure differential induced by the wing form alone for lift.
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Re: Hazards of frontier refuelling

Postby phavoc » Sat Aug 10, 2019 12:48 pm

Moppy wrote:
Sat Aug 10, 2019 4:08 am
phavoc wrote:
Sat Aug 10, 2019 3:37 am
If the first picture is an Airbus and not a 747 then why's it got a half-length upper deck at the top right of the picture? Which Airbus is it?

If we agree 747s have no flaperons, I'm OK.

I do wish people wouldn't keep repeating that the wing generates lift because of a curved upper surface vs a flat lower. It's really badly flawed due to inverted flight - and it's hilariously obvious because everyone has probably seen planes fly inverted. More correct to say that it's one of the contributing factors.

I've never seen an A-10 up close, so I'm not going to comment on how its control surfaces move.

edit: Logic dictates that the majority of the lift must come from the wing being tilted slightly upwards. Certainly this must exceed the "curved airfoil" component to enable inverted flight.
The A380 is the only other double decker plane. Both the 380 and 747 are falling out of favor with airlines due to increased costs associated with four engines instead of two. And a trend towards less mega flights. Who knows what will be there in ten years, but both aircraft will soon start to suffer parts issues if the flight base continues to shrink. One advantage the 747 has is the freighter variant.

As I said, it's more efficient wing design like that, however it's not the only version. Planes fly due to a combination of lift and thrust. If you have enough thrust you can almost overcome any lift issue, though there are limits since the faster you go the more drag you encounter, and also air pressure can eventually create a 'wall'. At points like that bad things tend to happen.

You can find images of the A10 and it's very large ailerons through a simple Google search. It's an amazing craft, but like all it works in certain environments and in others it does not.

You can go to NASAs site and look at some of the very interesting wing designs out there. Ingenuity and creativity have driven some amazing designs that at first blush should seem impossible but are not. The forward swept wing seems impossible, but it actually works, though only with a great deal of computer support. It's inherent instability allows it to do some crazy maneuvers.

There are some pretty incredible videos out there of aircraft doing amazing things. Seeing, I think it was an SU-50, flying in a straight line and then doing a controlled 360 and continuing to fly is amazing. Kudos to those crazy skilled pilots and their amazing flying machines.
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Re: Hazards of frontier refuelling

Postby Moppy » Sat Aug 10, 2019 2:50 pm

Can't be an A380 in the first photo as that has 2 full decks.

Coefficient of lift chart seems highly approximate. It's obvously not wrong but it probably covers a specific wing shape only, and not the whole plane.

748-800
calculated coefficient of lift @ max weight = 0.59
calculated coefficient of lift @ min weight = 0.29
coefficient of lift from chart = 0.80

Wing area (m2) = 554; Speed (m/s) = 255 @ 35K feet; Max takeoff weight (N) = 4_476_960; Operating empty weight (N) = 2,2012,800; air density (kg/m3) = 0.4135; angle of attack (level flight) = 2.4 degrees.

CL = (2 * weight) / (density * speed^2 * wing area)

2/3rd engine power is normal for routine operation. Additional power for unsual flight operations is therefore limited to 1/3. Unfortunately cannot calculate what % comes from wing shape vs angle, without knowing the speed when inverted (and the fuel delivery system might not even work upide down on a jetliner for extended periods; I've seen videos of them rolling 360 briefly though).
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Re: Hazards of frontier refuelling

Postby AnotherDilbert » Sat Aug 10, 2019 6:39 pm

Moppy wrote: Coefficient of lift chart seems highly approximate. It's obvously not wrong but it probably covers a specific wing shape only, and not the whole plane.
Yes, it's an example for a specific wing form, as specified in the preceding link.


The same diagram for a version of 747:
Image
http://www.aerospaceweb.org/question/ae ... 0252.shtml
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Re: Hazards of frontier refuelling

Postby Condottiere » Sat Aug 10, 2019 7:42 pm

I'm thinking weather radar.

As regards double decker economics, depends on passenger traffic, air corridor congestion, new airport construction, and expansion of existing facilities, which will all hit a wall at some point
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Re: Hazards of frontier refuelling

Postby Annatar Giftbringer » Sun Aug 11, 2019 7:58 pm

Regarding the difficulty of fuel skimming, the “skills and tasks” chapter of the Core Rulebook has a paragraph called “task checks”, that suggests that not every action needs a skill check.
“Core Rulebook, p.56” wrote:The referee should only call for checks when:
● The Travellers are in danger.
● The task is especially difficult or hazardous.
● The Travellers are under the pressure of time.
● Success or failure is especially important or
interesting.
So the question is, does a normal fuel skimming operation fulfill any of the above, or could we just assume that they manage?

As for whether expert programs can boost any skill or not, I have to say that I agree with and quite like AnotherDilbert’s interpretation and will henceforth apply it in my games (I.e expert programs are only limited to Int skills if the character is unskilled, when aiding a skilled character it can boost any skill).
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Re: Hazards of frontier refuelling

Postby Putraack » Fri Aug 16, 2019 2:50 am

Annatar Giftbringer wrote:
Sun Aug 11, 2019 7:58 pm
Regarding the difficulty of fuel skimming, the “skills and tasks” chapter of the Core Rulebook has a paragraph called “task checks”, that suggests that not every action needs a skill check.
“Core Rulebook, p.56” wrote:The referee should only call for checks when:
● The Travellers are in danger.
● The task is especially difficult or hazardous.
● The Travellers are under the pressure of time.
● Success or failure is especially important or
interesting.
So the question is, does a normal fuel skimming operation fulfill any of the above, or could we just assume that they manage?
IMO, if it's a Difficult check, then I think it qualifies as hazardous.

But what happens if the Pilot fails the check? Wreck the ship, or just damage it? Do they have to try again, or does it just take longer?
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Re: Hazards of frontier refuelling

Postby Linwood » Fri Aug 16, 2019 9:38 am

I suggest a minor negative effect just leads to less efficient fueling (so you have to go around and make a second attempt, maybe with a Handling penalty) or a problem with the fuel processing system requiring 1D hrs to repair. More serious fails could lead to more serious ship damage.
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Re: Hazards of frontier refuelling

Postby Sigtrygg » Fri Aug 16, 2019 11:06 am

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Re: Hazards of frontier refuelling

Postby Reynard » Fri Aug 16, 2019 11:12 am

The game should never be about killing off the players. Bad rolls can make things go very wrong but reading the rules literally and with no wiggle room is no fun.

Piloting the Deep is Difficult BUT circumstances vary. First, you don't have to skim the Deep. The Shallows and Extreme Shallows also have fuel at the cost of time but with less penalties to Piloting. Piloting skill does count and players should consider this when deciding how and where to skim. You can also take more time at any depth. This is why a lot of ships would rather buy fuel, free fuel isn't always free. A bad skimming might convince players it may be not worth it.

EFFECT is very important! This is what determines how well or poorly a skimming goes. Referees should have the Effect table memorized for gas skimming. A failure isn't an auto kill. Most of the time a failure is a few curses until the pilot corrects their mistake. Even an Exceptional Failure should be those famous cinematic roller coaster events with the ship rocking and tumbling, everyone screaming and pooping their flight suits, random sparks from random panels while lights flicker as everyone scrambles at their stations to hold the ship together and regain control (make your rolls now). Only reason you send the ship to those crushing depths is you were planning on terminating the game anyhow.

"Guys, I vote we stop at the station next time."
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Re: Hazards of frontier refuelling

Postby Condottiere » Fri Aug 16, 2019 5:05 pm

If you want to succeed you should strike out on new paths, rather than travel the worn paths of accepted success. I do not think that there is any other quality so essential to success of any kind as the quality of perseverance. It overcomes almost everything, even nature.

I always tried to turn every disaster into an opportunity.



- John the Rocketfeller

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