Orion aka "Ol' Boom-boom"

[nyrath]

In the above system as you stated it, the magazine's mass is being recalculated after every bomb. And the new mass is being added to the engine. (and the old mass deducted).

Since you're adding the mass of the magazine to the engine, please subtract it from the magazine

Better yet, calculate what the magazine's mass would be and add that to the engine, without ever changing the magazine's actual mass. (perhaps this is what you're actually doing)

Possibly better yet (though it may not allow for ejecting magazines or replacing them in flight or other strange behavior) but you could just Initialize by calculating the appropriate mass of all magazines and adding that to the engine, then when a bomb is expended simply deduct the mass of that bomb from the engine. Rather than recalculating magazine mass at all. (The magazines just always have their low constant mass).

Yes, I was already subtracting the mass of the magazine from the magazine, less 1 ton. I didn't want to get into tedious details. If anybody wants those, the source code is in the mod.

I might go with the system you propose (the third one, not recalculating, just deducting the mass from the engine), except it will get a tad more complicated when NovaSilisko starts jettisoning his Orion magazines. Or adding new full magazines when one refuels.

I did not use your proposed system initially since a career of being burnt by unexpected side effects make me habitually try to program the absolute minimum change possible. The more code your change, the more chances to spawn new bugs. Of course apparently that strategy did not work in this case.

[Anglave]

Yes, I was already subtracting the mass of the magazine from the magazine, less 1 ton. I didn't want to get into tedious details. If anybody wants those, the source code is in the mod.

I hadn't looked at your code. I suppose I should do that before brainstorming all over the floor.

I might go with the system you propose (the third one, not recalculating, just deducting the mass from the engine), except it will get a tad more complicated when NovaSilisko starts jettisoning his Orion magazines. Or adding new full magazines when one refuels.

Absolutely. Yeah, I was updating my post to say essentially the same thing, while you were writing this. I've finished editing my post now, hopefully it's more clear / useful. Didn't mean to overstep.

Edited June 7, 2013 by Anglave

[nyrath]

I've finished editing my post now, hopefully it's more clear / useful. Didn't mean to overstep.

No, no, you are not overstepping. I welcome your input. You solved the original problem, remember?

Progress report:

Ohboy, I'm surprised any of these Orions ever got off the launch pad.

First off due to some sloppy factoring on my part, there were not one but two places that I recalculate the mass, and of course I forgot to change the second (for people who do not write computer code for a living the translation is BAD programmer! BAD, BAD! No dog biscuit for you!) In other words, the magazines soon had their full mass. I've refactored it like I should have in the first place. This mistake is done by programmers who are amateurs, sloppy, or lazy. Sloppy in this case.

Secondly, if you have a launch pad accident and you do a restart, KSP will re-use the updated engine mass and start re-adding the virtual magazine mass for a second time. I will check but I'm afraid this will happen if you, say, switch from one vessel to another and back again. I hope not.

And I will try to make a new bomb type in between 3.5MN and 80MN. Would 40MN be suitable?

[NovaSilisko]

I'd go for something like 10 MN, or 20.

[nyrath]

I'd go for something like 10 MN, or 20.

Looks good. Lets see, 10MN is about x3, 15MN is about x4, and 20 is about x6 compared to a 3.5MN.

How about 10 MN?

[Canopus]

I'd like to have some 10 MN bombs.

[nyrath]

10 MN it is, then. By my interpolation, the mass per bomb will be about 0.146 tons, compared to 0.141 for the 3.5 MN. And a yield of 1.35 kilotons if anybody cares.

[NovaSilisko]

Might be part of the weird mass calculations mentioned earlier but I'm getting a bunch of complaints in the console about something being set to negative mass... Seems to have happened when I undocked a canister during flight and the entire ship exploded.

Edit: No, that just happened again with no negative mass errors. It seems the instant velocity shift while the canister is still in the payload area messes it up.

Edited June 7, 2013 by NovaSilisko

[nyrath]

New version for testing

This fixes the ultraheavy ship problem. Please test to be sure it does not un-fix the chattering magazine problem.

I've added the 10MN magazines.

I've also altered the mesh of the engine with the central column. Before, there was an invisible skin around the wire framework, so you could stick parts on thin air (because collision meshes have to be convex, and the areas for stacking magazines has to be concave). Now you can attach struts and RCS to the central column. This may or may not allow one to stack something other than magazines in the magazine framework.

Might be part of the weird mass calculations mentioned earlier but I'm getting a bunch of complaints in the console about something being set to negative mass... Seems to have happened when I undocked a canister during flight and the entire ship exploded.

Edit: No, that just happened again with no negative mass errors. It seems the instant velocity shift while the canister is still in the payload area messes it up.

Oh, dear. That sounds quite serious. I'll make a special build of the plugin without the "virtual mass" fix and email it to you. If that solves the exploding canister problem, I'll put a bool in the part.cfg that will disable the virtual mass patch on a part by part basis. Then you can set your canisters appropriately.

[Anglave]

Downloading v13 now.

In the meantime, this is still the ultraheavy version. Playing with decoupling magazines. I thought it might be related to Nova's explosion issue.

Working fine on ascent.

Decoupling the magazines worked great.

Though the engine still has the tooltip for them. Probably a low priority issue.

A nice circular orbit. The ejected magazines were destroyed by subsequent impulses, but that's to be expected.

[Mecha Pants]

As is the Kerbal way, I decided to jump past all reasonable launch vehicles and go strait for massive overkill.

The center unit gets it all off the ground on 400MN charges, once in orbit I drained the remaining 400MN charges through all seven engines up to its last recorded speed of 87,000 m/s.

just under 70k liquid fuel for the 6 FTM 240 proximity use engines, and about 4 thousand 3mn charges left...

Now I need to start building an interstellar colony to stick on top...

Also update to the new version.

Interestingly, the heavier the next thing after the engines is, the more stable it is on the launch pad. I can't get this beast to sit on the ground without flying away unless I have at least one full large spherical tank and six 400MN magazines sitting on the center engine.

Edited June 7, 2013 by Mecha Pants

[Anglave]

New version for testing

This fixes the ultraheavy ship problem. Please test to be sure it does not un-fix the chattering magazine problem.

Success.

I've added the 10MN magazines.

Success. However, still a little anemic. 20NM instead?

The 10MN charges make the above pictured ship "just less than hover" at full throttle. The 80MN charges make it tear out of the atmosphere hard enough to make plasma.

I've also altered the mesh of the engine with the central column. Before, there was an invisible skin around the wire framework, so you could stick parts on thin air (because collision meshes have to be convex, and the areas for stacking magazines has to be concave). Now you can attach struts and RCS to the central column. This may or may not allow one to stack something other than magazines in the magazine framework.

Success!

[nyrath]

As is the Kerbal way, I decided to jump past all reasonable launch vehicles and go strait for massive overkill.

The center unit gets it all off the ground on 400MN charges, once in orbit I drained the remaining 400MN charges through all seven engines up to its last recorded speed of 87,000 m/s.

just under 70k liquid fuel for the 6 FTM 240 proximity use engines, and about 4 thousand 3mn charges left...

Now I need to start building an interstellar colony to stick on top...

Also update to the new version.

Interestingly, the heavier the next thing after the engines is, the more stable it is on the launch pad. I can't get this beast to sit on the ground without flying away unless I have at least one full large spherical tank and six 400MN magazines sitting on the center engine.

Sufferin' Heinlein! And I thought this monster was bad!

Working with these dense objects one rapidly discovers that for KSP, ship balance is very critical.

Frankly I'm surprised that your ship flew. My virtual mass system is not intelligent enough to deal with multiple Orion engines, it just dumps all the mass into the last Orion engine in the vessel's list of parts. This is due to a variety of issues which I will not bore you with here.

I have discovered the hard way that pumping all the mass into the engine makes the ship unbelievably tail-heavy. This means my advanced SAS module on the nose cannot turn the ship faster than a crawl, and it is constantly jittering the ship. I could only rotate fast if I coated the ship with RCS.

Success. However, still a little anemic. 20NM instead?

I'm glad you can put things in the magazine bays now. It took a bit of modeling but it was worth it.

20NM coming up!

Actually, Anglave, could you do me a favor?

In the USAFOrionMag1_35kt10mn folder, edit the part.cfg file, changing the value of bombImpulse to test values from 20000 to 80000, and see which one seems most useful to you.

I do not want to fill up the VAB propulsion tab with zillions of magazines. I'll keep the 10MN, plus a new one with whatever value you think is best.

Edited June 7, 2013 by nyrath

[Anglave]

Actually, Anglave, could you do me a favor?

In the USAFOrionMag1_35kt10mn folder, edit the part.cfg file, changing the value of bombImpulse to test values from 20000 to 80000, and see which one seems most useful to you.

Absolutely, though it may have to wait. I'm headed home for the day.

I wanted to report, I used the Orion on an actual mission this afternoon. Target: Jool and her moons

Everything went smoothly, except I tried a very non-Hohmann transfer. We got there, but it took a ridiculous amount of ÃŽâ€v

I did notice one odity:

The Orion is not active and has not fired recently. It's being heated by three stock 909 engines mounted on my lander (which I was using very ineffectually for fine control). Notice that it is nearly overheated, while the 909's are cool to the touch.

Despite the lack of fine control, we were able to aerobrake at Jool

And almost able to slow down enough to capture at Val (a better Jool aerobrake would have done it, I was being sloppy)

Luckily, the lander has quite a bit of ÃŽâ€v itself, and was able to complete the capture

Unfortunately, the Orion vessel I was counting on using as a return craft is out of charges. I'll just have to try again, but bigger!

[nyrath]

Great mission!

But I have no idea why the engine is overheating like that!

[Anglave]

Actually, Anglave, could you do me a favor?

In the USAFOrionMag1_35kt10mn folder, edit the part.cfg file, changing the value of bombImpulse to test values from 20000 to 80000, and see which one seems most useful to you.

I do not want to fill up the VAB propulsion tab with zillions of magazines. I'll keep the 10MN, plus a new one with whatever value you think is best.

For comparison, the 10MN charges achieved a TWR < 1 (I'd guess about 0.8) at full throttle using the craft pictured below.

I modified the 10MN charges, making them 20MN instead:

1.5 kt with 20,000 kiloNewtons = 0.290 tons

bombImpulse = 20000

bombMass = 0.29

This was sufficient to loft my 898 Mg craft (173 Mg payload) to 80 Km LKO using 229 charges, and at about 33% throttle until after the gravity turn.

This seems much more reasonable to me than the huge impulse from the 80MN and insane 400MN charges. 4-6 magazines of 20MN charges gets a reasonable (for Orion) payload to orbit, with an acceleration curve within the approximately right range for Kerbin's atmosphere. Unreasonable payloads use the 80MN charges. Large cities and small continents use the 400MN charges.

I can see retaining the tiny cap-gun 0.88MN charges. It's occasionally handy to have a low thrust option. I could have used some in setting up my Jool aerobrake, where the 3.5MN charges were giving me about 6 m/s change, and I wanted to make some 1 or 2 m/s changes.

I would think that 2MN and 3.5MN are close enough that for gameplay purposes, they're interchangeable. Not sure it's value added to retain both, and unless the 2MN charges have an extreme efficiency advantage, I'll always pick the 3.5's.

A 10MN charge may loft small payloads (though why you'd use Orion to launch a satellite I'm not sure), or be useful for low-impulse in-system maneuvers. Though again, from a gameplay perspective, unless they're much more efficient I'm likely to select a denser 'fuel'.

The 20MN charges seem good for launching reasonable payloads from Kerbin, they make the "throttle setting" meaningful.

The 80MN charges would loft a large payload, or be the major ÃŽâ€v contributors to an interplanetary crossing.

The 400MN charges exemplify a core KSP principle. Namely, "Moar explodey!"

In my mind, the Orion basically needs a "rough", "normal" and "fine tune" charge, scaled to the payload.

So, for a reasonable to reasonable-large scale mission within the Kerbal system, I would probably load one layer of 20MN for ascent, one layer of 80MN for accel to and decel at the target, a few 2MN for little nudges and a few 0.88MN for really fine corrections. Fill in the rest with charges appropriate to the mission objectives, but my guess would be mostly 20's and 80's.

My Jool mission packed mostly 3.5's, and I expended the majority of those accelerating to Jool intercept, and then correcting my terrible orbital inclination after the flyby. More 20's and 80's would have been welcome (I had a couple multiple-minute burns at full throttle on the 3.5's).

Edited June 8, 2013 by Anglave

[Anglave]

This does bring up the question of fuel density. The mass of the devices is scaled as realistically as possible for each charge (barring the 20's, which I just guessed at). However, there are the same number of devices in the 2MN magazine as the 80MN and 400MN magazines. Making their fuel density much different.

Fuel mass is critically important to mission design and engine/fuel selection. But volume is also important. The way things are balanced right now, as a mission planner I'd want to use the 400MN charges whenever possible, just so I could send the most ÃŽâ€v with the mission. Not only are the 400MN charges more than 4x as efficient by mass (the 2MN get 25,316 kn/t whereas the 400MN get 108,695 kn/t), they're also 200x as efficient in volume. (you can fit 24,000MN of 400's in one standard size magazine, or 120MN of 2's).

I understand that in reality, much of the device's mass is casing, wiring, conventional explosives, safety, and other inert stuff, and only a small fraction of its mass is blutonium. Meaning that doubling a device's yield doesn't nearly double its mass or volume.

I'm just pointing out that, within the world of KSP, this means we'll always want to use the largest charges we can get away with unless there's some artificial restriction. A 10x400MN magazine still has more than 25 times the potential ÃŽâ€v of a 'standard' 60x2MN magazine. Every time you can use one of those huge charges (and not way overshoot), it's a win.

Update: I mentioned above that achieving LKO takes about 225 of the 20MN charges (4500 MN total impulse, and interestingly about 4500 m/s for ascent). It takes just over 13 of the 400MN charges (I used 14 for 5,600 MN total). More loss to atmospheric drag, and the 14th charge didn't give me a nice pretty circle. But I spent 51.52 tons of 400MN devices vs. 65.25 tons of 20MN devices, and ended up with a higher orbit.

Perhaps when money becomes an actual resource in the game, the cost of the larger charges should scale in the same manner as their efficiency?

Edited June 8, 2013 by Anglave

[NovaSilisko]

[Canopus]

i can see where the artstyle of the stockparts comes from. What fits into the cargo bay?

[Needles_10]

Nova: That's a nice-looking picture! Why, though, is the ship at that angle?

[Canopus]

Nova: That's a nice-looking picture! Why, though, is the ship at that angle?

Space is three dimensional

[NovaSilisko]

i can see where the artstyle of the stockparts comes from. What fits into the cargo bay?

Here it is spitting out a 3m tank from KW

[Canopus]

Will it come with interior and how many Kerbals will it hold? btw i love the way it looks steal plated and heavy contrary to other stock parts.

[NovaSilisko]

Yeah, it comes with an interior. Still need to model that and the radially-mounted engines though. Seats 6 kerbs, but there's a lot of room so I might bump it up to 8 or 10.

[Canopus]

Sounds amazing. And what about the black cylinders? Are those the magazines?