Sublight Speed

[Jefffar]

I agree, but remember, in Robotech/Macross the fighters still were Mach

[Tinker Dragoon]

... Robotech?

At any rate, yes, someone should, since mach numbers don't make sense for vehicles traveling in the airless environs of outer space.

[Tinker Dragoon]

Actually it isn't a measure of speed at all, it's the ratio of an object's speed to the speed of sound. Contrary to what is printed in Palladium books, the speed of sound in air is not constant, but in fact decreases with altitude (technically, it varies with pressure and temperature, but both of these change with altitude). In outer space this results in non-real numbers.

But ignoring that and just going with the constant speed of sound given in the books, one quickly finds that the books disagree on just how fast Mach 1 is. For example, in Heroes Unlimited, the speed of sound is stated to be 700 MPH, while TMNT lists it as 660 MPH, and in Rifts it varies from book to book. This makes converting to a fraction of the speed of light difficult, because two vehicles with the same Mach number listed for speed may have very different speeds when listed in MPH. Do you change them to match? And what if no MPH is listed? Very annoying.

[Jack Daniels]

Actually it isn't a measure of speed at all, it's the ratio of an object's speed to the speed of sound. Contrary to what is printed in Palladium books, the speed of sound in air is not constant, but in fact decreases with altitude (technically, it varies with pressure and temperature, but both of these change with altitude). In outer space this results in non-real numbers.

And yes, I also realised that the MPH in several of those books are different for Mach 1. However, I based my calculations on the actual Mach speed. It is indeed very fustrating, but I would suggest to use the correct one, 1225kmph or 761.2mph (info from wikipedia).

Except that what he said is that the speed of Mach 1 varies based on atmospheric conditions. Your "actual Mach speed" of 1225 kph is only correct sometimes. Thus the problem with using Mach to measure speed for space ships. Using it as a relative comparison between different ships could work, but only if the authors agreed to use a standard Mach speed. Really they should use G's of acceleration for "speeds" and lightspeed ratios for more advanced engine types.

[Daikuma]

Don't mess with these figures, they have enough trouble getting consistency in rifts books, and if they change the speed ratios now, you know they will never go back and "correct" all of the existing materials.

Kitsune (his web handle, don't know his real name but does GREAT Phase world conversions of popular sci-fi materials) has an alternate speed scale for PW somewhere on his web site, based on acceleration, and percentage of the speed of light, including time attenuations.

Awesome work, and way too much thinking for a somple saturday night game.

-Daikuma

[glitterboy2098]

after experimenting with accelleration based mechanics (wound up too difficult to use), i finally settled on units of 1 AU per day, as per manhunter. i refer to these as a Mark, as per some of the people on this board had previously suggested, and recalling the GalaxyQuest movie.

one mark works out to .5559402% C

so the Naruni Fire Eater, with it's 20 mach speed, becomes 20 Mark's, or 11.12% C (rounded). very impressive. the fastest warship would at best hit 5%.


after this, all that was required was a quick rewrite of the missile charts to standardize them to the new space speeds, and multiplying weapons ranges in space by 10 to take combat to a more beleivable distance.


now if i can only get people interested in a phase world game where i am.

[Daikuma]

Wow! Someone is going around and digging up long buried threads like this one.

Sorry, I missed a lot of the meetings...

Hi, my name is Daikuma, and I'm habitually late...

[Aramanthus]

I use somebody else's rules they came up with for sublight speed. They are very good about those. And recently he came up with Inertialess speed conversion. I"m in the process of using thoise too.

[Nekira Sudacne]

Ninjas and Superspys has a Speed Factor system that's not based on Mach, prehaps that is useable?

[Aramanthus]

I think you'd have to extend it tremendously to make it useful for sublight speeds.

[Nekira Sudacne]

I think you'd have to extend it tremendously to make it useful for sublight speeds.

So?

[Aramanthus]

I will continue to use the system someone I know came up with. It is better than the pseed factor!

Besides it is specifocally made for Phase world, it is not a conversion!

[Aramanthus]

INteresting idea Gadrin, but you would have to greatly expand those speeds. Up until the 60% of the SOL range.

[Aramanthus]

That sounds pretty good Gadrin! I think that would work very well. And it is pretty close to what I'm using. Although not quite the same.

[Aramanthus]

How could that simplify it Darkmax? Just curious.

[Aramanthus]

It might be possible. But it'd take some work. And a lot of cooperation from the forum users / GMs and players who want to contribute to it's creation.

[Esckey]

Many of the russian jets from the cold war era could push their engines beyond max, but it fried the engine completly in some cases

[Aramanthus]

I've heard that about the Russian jets too.

[Aramanthus]

The Russian during the cold war would push their jets to way over the engines level of capabilities, (I.E. over 100%) and their engines could handle it for a short time. But the engines could only handle so much stress. When the pilots would land the crew had to scrap them.