Thankyou very much, it is inline with what I have been using
Skimming gas giants
- Thread starter Blue Ghost
- Start date
Thankyou very much, it is inline with what I have been using
In MgT: Fuel Processors
"Fuel processors convert unrefined fuel into refined fuel. One ton
of fuel processors can convert 20 tons of unrefined hydrogen into
refined fuel per day."
A lifting body will get you to a certain altitude, but as you go higher, thinner atmosphere means less lift, no? If the ship doesn't generate enough thrust, then it's going to find itself stuck at the altitude where the lift it generates plus the thrust it generates are balanced by the planet's pull and the drag created by atmosphere. It won't be able to get above that.
MgT is Mongoose?
yep
The other problem with lifting bodies is stability. It's been about 20 years since I studied them, but when NASA was doing their X-plane tests there was a tendency for some for some of the craft to oscillate. The most famous being the one used in "The 6 Million Dollar Man" intro back in the 70s. I can't recall the reason nor how they solved the problem, because they did, but another design concept came along that temporarily pushed the lifting body on the back burner.
That's no longer the case as Japan with HOTOL, the ESA's Europlane, the French with a similar design, and the former Soviet space program all have lifting body designs for their mini shuttles. They're essentially the same design, although Japan's HOTOL looks a lot like NASA's "Dyna-soar" from way back in the 60s or early 70s.
Link; http://www.brighthub.com/science/space/articles/46285.aspx
Getting back to gas giant skimming; I'm thinking there's an opportunity here to create some rules for skimming to address aspects of the exercise that weren't fleshed out.
Site says the oscillation problem was pilot-induced: the pilots weren't getting the response they expected when trying to compensate for rolls and therefore overcompensated, then overcompensated the other way, then ... you get the point. It's possible that wider lift-body designs are less vulnerable to that. It's also possible that introducing computers into the loop may have provided greater stability. Site says the big spectacular crash occurred because the pilot misjudged the landing - between dealing with the rolls and a rescue chopper that he thought was too close, he ended up over an unmarked section of the test area and misjudged his altitude while trying to land the plane, landing with the gear not fully deployed.
http://en.wikipedia.org/wiki/Northrop_M2-F2
Here's an interesting aside:
http://en.wikipedia.org/wiki/1983_Negev_mid-air_collision
F15's designed so the main body provides some lift. In this collision, the F15 lost all but 2 feet of one wing. The pilot went into a spin but was able to pull out and keep the plane stable by hitting afterburners: the remaining stub of wing and the plane's shape provided enough lift to keep it from heeling over. The pilot had to land it at afterburner speed, but he got it down and it was repaired and was able to fly again later.
Yeah, it's called PIO, or Pilot Induced Oscillation, as you say the pilot puts the stick in one direction, doesn't get a timely response, then pushes or pulls it in the opposite direction all the while the craft is still responding to the previous input. The best way to get out of that is to let go of the controls temporarily, let the plane sort itself out, then take control once more.
I've heard the F-15 story, but I'm skeptical. It was allegedly an Israeli F-15, and I always wondered how much of that story was hokum to throw off the Syrians and Iraqis. But, as it applies to starships, Traveller starships, like a lot of starships, lean towards a "coolness factor" when it comes to designs.
Most sci-fi ships have noses or leading surfaces that slope down because it looks cool like a race car. A lot of other cool sci-fi stuff is designed that way; example, the Seaview from "Voyage to the Bottom of the Sea", were it actually built, would have a horribly tendency to nose down into the water because of its nose design
Which is why I always tend to think that grav drives have a larger effect than is noted in the rules.
I've heard the F-15 story, but I'm skeptical. It was allegedly an Israeli F-15, and I always wondered how much of that story was hokum to throw off the Syrians and Iraqis. But, as it applies to starships, Traveller starships, like a lot of starships, lean towards a "coolness factor" when it comes to designs.
Most sci-fi ships have noses or leading surfaces that slope down because it looks cool like a race car. A lot of other cool sci-fi stuff is designed that way; example, the Seaview from "Voyage to the Bottom of the Sea", were it actually built, would have a horribly tendency to nose down into the water because of its nose design
Which is why I always tend to think that grav drives have a larger effect than is noted in the rules.
It's a true story. Also, the early problems with instability were solved in the same way they did with the F-16, F-17, B-2, F-22 & F-35. A computer monitors and controls all flight control surfaces. The pilot doesn't.
Hi,
I believe that the original M2-F2 lifting body that crashed was also modified with an additional center fin to help control pilot induced oscillation, as noted in the Wikipedia article at this link ( http://en.wikipedia.org/wiki/Northrop_M2-F3 ) which notes;
"While the M2-F3 was still demanding to fly, the center fin eliminated the high risk of pilot induced oscillation (PIO) that was characteristic of the M2-F2."
M2-F3
M2-F3
I believe that the original M2-F2 lifting body that crashed was also modified with an additional center fin to help control pilot induced oscillation, as noted in the Wikipedia article at this link ( http://en.wikipedia.org/wiki/Northrop_M2-F3 ) which notes;
"While the M2-F3 was still demanding to fly, the center fin eliminated the high risk of pilot induced oscillation (PIO) that was characteristic of the M2-F2."
M2-F3
M2-F3
So we need what; an intake rate to fill tanks, and a purification rate that is perhaps based on MT's little snippit.
We can go with the variable in MegaTrav for intake time, or we can assume that there's some obscure industry standard by which manufacturers make vents just big enough that all craft take 140 minutes to fill, or we come up with whatever seems reasonable to us. 140 minutes, or three hours in MegaTrav, is clearly a reasonable lower time limit. You can double that for a 1G free trader without too much argument, or keep it on the argument that the free trader, despite its lower performance drive, has a lower percentage of tank to intake than the fueler.
Well, maybe something based on speed and air density might be fun for the super starship tech-geek who has some interest in flight mechanics.
I'm just thinking out loud.
I'm just thinking out loud.
Actually a cool thing about the F-16 is the AFTI project where the computer controls all these small control surfaces on everything including the weapons pylons to maintain stable flight in an airframe that is purposfully unstable so it responds better.
Yes, same overall system.
