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[PART, 1.0.2] Anatid Robotics / MuMech - MechJeb - Autopilot - Historical thread


r4m0n

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I have unfortunately I have, was moments from landing a prototype interplanetary spacedock in the sea, it hadn't really passed the mustard for what I needed. It was all going so well! The chutes had deployed and I was within the landing tolerances, then the engines fired and all hell broke loose it pitched up, lost the chutes, and promptly hit the water too fast and shattered! The only plus side is that the kerbals survived because the cockpit managed to be slowed down enough as the ship disintegrated!!!!

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First of all, apologies if this has been asked before, I have not read the entire 153 page thread (that's about a typical novel...).

Is there a way to limit thrust on the Ascent Guidance module?

As it works now, I have a rocket that can easily manage at 1/3 of full throttle through the thicker atmosphere at lower altitudes, but MechJeb insists on going as full throttle as overheating restrictions allow, wasting lots of fuel simple pushing air out the way, without actually gaining much speed. It would be nice if the rate of ascent was limited by atmospheric density.

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First of all, apologies if this has been asked before, I have not read the entire 153 page thread (that's about a typical novel...).

Is there a way to limit thrust on the Ascent Guidance module?

As it works now, I have a rocket that can easily manage at 1/3 of full throttle through the thicker atmosphere at lower altitudes, but MechJeb insists on going as full throttle as overheating restrictions allow, wasting lots of fuel simple pushing air out the way, without actually gaining much speed. It would be nice if the rate of ascent was limited by atmospheric density.

a few ways, .. open the Throttle control page.

you can limit by %

by prevent overheat

acceleration x m/s/s

and terminal velocity <--- this is the one you are looking for. thrusting PAST terminal velocity is a waste of fuel true. but it will thust @100% up to that point.

etc

Edited by Fyrem
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OK, but no way to limit by ascent speed and atmosphere? It seems a bit fiddly to continually change %. Acceleration is not what I want to limit. Terminal velocity is not what I want to limit either, I just don't want it to keep trying to push above 200m/s at low altitude.

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no , you are not understanding. Limit to Terminal Velosity IS limiting while in atmosphere.

All thust while in atmo is fine, UP TO and NOT PAST "Terminal Velosity" this is where air multiplies its resistance. trying to burn Faster that this speed is very wastefull.

Trying to burn SLOWER than this speed, when you could go faster, is also wastefull, because you are staying deep in the gravity of the planet when you could have moved further away.

Best case is to : a) full thust UP TO terminal velosity.

B) lower throttle to maintain just a touch under terminal velostiy. (note, Tv changes as you go up, so you can slowly add throttle back in).

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Is there an issue using the nuclearEngine as an upper stage with MechJeb Ascent Guidance function? When I switch from a conventional to the nuke engine, the ascent steering is all wonky and that's before I even have started to use the nuke upper stage. I just want to know if it's MechJeb or just something I'm doing that's wonky:blush:

No problems with nuclear engines, I use them all the time. The problem is that the engine is probably a lot heavier than the engine you had on the top before. This has changed the center of gravity on your rocket and made it much more difficult to control. Try adding stabilizers, or replace some non-vectored engines with vectored ones if that's an option.

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no , you are not understanding. Limit to Terminal Velosity IS limiting while in atmosphere.

All thust while in atmo is fine, UP TO and NOT PAST "Terminal Velosity" this is where air multiplies its resistance. trying to burn Faster that this speed is very wastefull.

Trying to burn SLOWER than this speed, when you could go faster, is also wastefull, because you are staying deep in the gravity of the planet when you could have moved further away.

Best case is to : a) full thust UP TO terminal velosity.

B) lower throttle to maintain just a touch under terminal velostiy. (note, Tv changes as you go up, so you can slowly add throttle back in).

OK, I thought termainal velocity, in this case, was the intended orbit velocity.

Still, I have a rocket with a 2.5 - 2.7 T/W ratio in the first stages (it's intended as a heavy lifter, but most lifts I do aren't very heavy...), and it reaches 200 m/s quickly. Still, it continues to run full throttle (or rather, 95 % to prevent overheating), even with "limit to terminal velocity" active. If I run it on manual, the same rocket can keep a steady 200 m/s on 30-35% throttle, no problem.

So, in my head, things still don't add up.

I'll do some tests with a lighter rocket, so I get a framerate that doesn't look like a slideshow and see what happens.

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it reaches 200 m/s quickly. Still, it continues to run full throttle

You have FAR installed. FAR lies to MJ saying that it has no air resistance whatsoever.

Correct guess?

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You have FAR installed. FAR lies to MJ saying that it has no air resistance whatsoever.

Correct guess?

FAR?

The only mods I use are MechJeb, HayStack, Subassembly Loader and Docking Struts.

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Make a customer window, add terminal velocity and surface velocity to them and watch mechjeb barely touch terminal. You won't see the throttle move most times it's such a small increment but it works great.

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I apologise if this has already been asked (skimmed comments, couldn't see it) - but does MechJeb 1 work with KSP 0.20? Some of my old space stations still use it, so would either have to deorbit them or just start afresh if MechJeb breaks them.

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I apologise if this has already been asked (skimmed comments, couldn't see it) - but does MechJeb 1 work with KSP 0.20? Some of my old space stations still use it, so would either have to deorbit them or just start afresh if MechJeb breaks them.

I'm hoping the trick of changing the config file for the old parts works, like it did in .19. I won't be able to test it much tonight, though, then I'm going away for the holiday weekend, so I won't be back to try it again until late Monday. I'm sure by then the solution or lack thereof will have been posted. :-)

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No problems with nuclear engines, I use them all the time. The problem is that the engine is probably a lot heavier than the engine you had on the top before. This has changed the center of gravity on your rocket and made it much more difficult to control. Try adding stabilizers, or replace some non-vectored engines with vectored ones if that's an option.

Ah, so it is me:D. Thanks for the info, I'll give that a try.

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I'm hoping the trick of changing the config file for the old parts works, like it did in .19. I won't be able to test it much tonight, though, then I'm going away for the holiday weekend, so I won't be back to try it again until late Monday. I'm sure by then the solution or lack thereof will have been posted. :-)

I tried this and ran into some issues. Some of the MJ1 parts have messed up textures, and trying to place them in the VAB just drops them down and you cannot click on them or move them. You also have to change the allowSurfaceAttachment rule to 1 or else you can't use it as your starting command module. I have no idea what happens if you try to load up an already existing craft that uses them though.

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I already have Jet/Rockets. And work like wise with Mj.

Search for the STAR Series in the Craft Exchange....

You have some nice crafts there.

What I'm talking about is detaching Jet Engines as the first stage of a rocket design. Your designs are VTOL and SSTO. I have a variety of such crafts already.

My current project is a heavy lifter. MechJeb Ascent Autopilot doesn't seem to recognize my Jet stage as even being there.

Would be nice to have a feature in MechJeb Ascent Autopilot to jettison a stage (jet or rocket) at a predetermined altitude, even if there's fuel left in the stage. Or in the case of Jets, perhaps at a predetermined level of air intake?

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MechJeb2 doesnt work on OSX I think.

I copied the folder in GameData, and MechJeb also was for a short moment on the loading screen. But ingame, was nothing (no pods, nothing).

Anyone can help out? MacUser maybe confirm?

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MechJeb2 doesnt work on OSX I think.

I copied the folder in GameData, and MechJeb also was for a short moment on the loading screen. But ingame, was nothing (no pods, nothing).

Anyone can help out? MacUser maybe confirm?

I use it in OSX seamlessly.

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I use it in OSX seamlessly.

So you also just copied the MechJeb2 Folder in the Gamedata, where it rests next to the "Squad" one?

Dammit, cant make it work :(

Edit: or do I miss a step regarding the "parts" ?

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Place the MechJeb2 folder into [Wherever you have KSP]>GameData. Directory should be [KSP]>GameData>MechJeb2>[Parts, Plugins]

Also, it seems to me that MechJeb hasn't been properly updated for use with 0.20, as it still creates and uses the folders [KSP]>Plugins and [KSP]>PluginData. Maybe I'm wrong, but as I understand it, those should be held in [KSP]>GameData>MechJeb2, should they not?

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