[1.12.x] Anatid Robotics / MuMech - MechJeb - Autopilot - [2.14.3] [4th March 2023]

[MikeO89]

Ok, I finally got it by rotating the root part 90°. Now no roll to orbit (and I can leave Mechjeb Force Roll off). Thanks Space Kadet for pointing that out (I didn't know the game is orientating the craft North instead of East, that explains the roll I was having at every launch). During the spin around of the root part in the VAB, I lost track of which way it was supposed to be. I ended up rotating with shift Q and trying it out on launch until I got the position of the root part correct. How do I know which direction the root part is facing in the VAB (especially if the root is something other than a command pod) so I don't lose track of the orientation again?

Edited May 30, 2018 by MikeO89

[AlonzoTG]

The fundamental issue here is that if you select a standard roll angle for launch, Mechjeb will do the correct 90 degree roll. However, if you DESELECT force roll, it will execute a ~270 degree roll coming off the pad in the other direction. If you launch with force roll enabled, and then disable it mid-flight, it performs as expected. The problem is when you launch with force roll DISABLED. It executes a completely crazy roll DESPITE being set not to. 

[MikeO89]

1 hour ago, AlonzoTG said:

The fundamental issue here is that if you select a standard roll angle for launch, Mechjeb will do the correct 90 degree roll. However, if you DESELECT force roll, it will execute a ~270 degree roll coming off the pad in the other direction. If you launch with force roll enabled, and then disable it mid-flight, it performs as expected. The problem is when you launch with force roll DISABLED. It executes a completely crazy roll DESPITE being set not to. 

It hasn't worked that way for me flying this Falcon Heavy type craft (center stage with 2 side boosters). Leaving Mechjeb Force roll on it's default of 90° 90° didn't come out right in relation to the side boosters staying flat and not up and down (or in between) along it's course. Of course I can't swear I didn't accidentally roll parts of the craft in the VAB during assembly to some weird position. As I said before, I never even noticed this until I tried to fly a craft with 2 side boosters as flying without side boosters or flying with 4 side boosters, I wasn't paying that much attention to the roll orientation as no matter which way it ended up, it was still in an ok position (or looked to be). Not so when flying 2 side boosters as the roll position becomes apparent really fast.

Edited May 30, 2018 by MikeO89

[Gordon Dry]

@MikeO89 it's a little weird but the MechJeb set roll angle is relative to the vessel's orientation - so when the craft is oriented east and you set roll to 90° it rotates out of the desired rotation - set it to 0°

[El Sancho]

26 minutes ago, Gordon Dry said:

@MikeO89 it's a little weird but the MechJeb set roll angle is relative to the vessel's orientation - so when the craft is oriented east and you set roll to 90° it rotates out of the desired rotation - set it to 0°

Oddly enough, Gordon, that's not how it works for me.

I habitually put the MJ module on the left side, as I am looking out the door of the VAB from the default camera position. I set Force Roll to the default 90 degrees, and My rockets don't roll at all.

[Gordon Dry]

@El Sancho perhaps I don't have this problem because I just use embedded MechJeb functionality (integrated into the pod), no attached thingie

and btw the root part's orientation counts ...

Edited May 30, 2018 by Gordon Dry

[Capt. Hunt]

Force roll is relative to the orientation of the command pod.  Lets say it's a manned pod, picture an arrow up the pilot's spine, by default mechjeb will turn the ship to point that arrow straight up (0^o).  Force roll will override that to whatever angle you choose.  Note: it also adjusts for inclination, so even if you are launching retrograde, if you set it to 0^o, your command pod will be upright.  I usually set the turn and climb angles to either 0^o or 180^o.  Rockets will usually perform their climb roll almost immediately off the pad (IRL they do so as soon as they clear the launch tower).  You don't need to set different numbers here, unless you want the rocket to rotate a second time during the gravity turn.

Edited May 31, 2018 by Capt. Hunt

[Space_Kadet]

7 hours ago, Gordon Dry said:

@MikeO89 or use

 

 

This is really a mod?

All you have to do is Ctrl + Q

(on the root part when done building)

 

That is it.. build the rocket you want, and then press Ctlr + Q

[El Sancho]

 

I admit I don't understand any of the comments on this subject. It's like you guys were all speaking Greek or something...

[Space_Kadet]

5 hours ago, MikeO89 said:

Ok, I finally got it by rotating the root part 90°. Now no roll to orbit

1

You're welcome. Glad I could help your space program progress!

 

I do admit, the 90 Degree roll looks cool as all give a &*^#'s on launch, but is completely useless when trying to maximize efficiency in a launch. Thus why I do not use it.

12 minutes ago, El Sancho said:

 

I admit I don't understand any of the comments on this subject. It's like you guys were all speaking Greek or something...

 

Well, being from Buenos Aires... and native language is probably Spanish (maybe Portuguese if you on a border to another country)

 

 

*Defining terms*

Pitch, (up and down movement)

Yaw, ( Left and right movement)

Roll ( twisting movement)

 

 

 

They are talking about how when launching,  a rocket can *Roll when launched (Depending on how it was built in the VAB)

 

https://translate.google.com/#en/es/Well%2C being from Buenos Aires... and native language is probably Spanish (maybe Portuguese if you on a border to another country) Defining terms%3A Pitch%2C (up and down movement) Yaw%2C ( Left and right movement) Roll ( twisting movement) They are talking about how when launching%2C that a rocket can Roll when launched (Depending on how it was built in the VAB)

Edited May 31, 2018 by Space_Kadet

[Space_Kadet]

53 minutes ago, El Sancho said:

 

I admit I don't understand any of the comments on this subject. It's like you guys were all speaking Greek or something...

 I just read this over and I realized that you're sentence structure and manipulation of the English language is commanding. So I want to reply to my previous comment that I did not mean to sound like a Baboso

 

Edited May 31, 2018 by Space_Kadet

[Gilph]

Hi, I recently had to revert back to dev 800 from dev 801 due to some severe issues with the new landing changes.

Scenario in 1.4.3 with dev 801:

1. Smallish Mun lander in circular 400k orbit around the Mun. No RCS on vessel
2. Changed Pe to 15k
3. at 15k, selected Land Anywhere
4. Just above the surface, the craft oriented itself vertically but still had a large horizontal speed (~10m/s). It slowly lost altitude while skimming over the surface for about a minute and crashed into the side of a hill, killing 7 tourists.

It seems the new code has some heavy reliance on RCS and does some auto enabling of attitude control. I'm not sure that's the best way to handle most cases. TBH, I always found the Land Anywhere code to be very good, with only occasionally minor hiccups. I would suggest:

• Auto Enabling RCS is a mistake. In Career mode, it is common to make landers that to not need docking, so RCS is not added. Also, RCS should not play a role in Land Anywhere, unless the user enables the RCS button and RCS is present..
• Main engines should always kill horizontal speed. The only thing that needed attention was the occasional flipping of the vessel excessively at the end to eliminate the last bit of horizontal velocity. Maybe raising the altitude a little and a gentler deceleration at the very end will fix that. If you detect that RCS button is pushed and RCS is actually present on the vessel, it can be used. Especially with Land at Target, where you are descending from a 500m height and you are a bit off, RCS can help on the way down

Thanks

 

[El Sancho]

On 5/30/2018 at 11:50 PM, Space_Kadet said:

 I just read this over and I realized that you're sentence structure and manipulation of the English language is commanding. So I want to reply to my previous comment that I did not mean to sound like a Baboso

 

Absolutely not a problem, my friend. No offense taken, and no apologies needed. In truth, I am from the USA. I've been an expat for about 4 years now, but your assumption was entirely reasonable, based upon the information available to you

What was confusing me was the way the issues were being discussed. I am quite familiar with the unwanted roll shortly after launch issue. I wrestled with that for months, and tried rotating the capsule (is this what they mean by "root"??) and rotating the whole rocket and everything under the sun, with wildly inconsistent results.

Then I hit upon my current solution, as stated above, "I habitually put the MJ module on the left side, as I am looking out the door of the VAB from the default camera position. I set Force Roll to the default 90 degrees, and My rockets don't roll at all."

This solved the problem absolutely, permanently, and with 100% consistency, for me. Now, there was also some discussion as to whether the location/orientation of the MJ module itself made any difference; the error messages in the VAB are ambiguous in that regard. I was just saying that the great long involved discussion between Gordon, Alonzo, and Mikeo89 had left me in the dust, intellectually speaking. I did go to university, yes, but a 4-year Liberal Arts degree from a notorious Southern California party school (GO AZTECS!) doesn't really help all that much when it comes to rocket science...

Which reminds me of a story...

The college graduate with an Engineering degree asks, "How does it work?"

The college graduate with a Physics degree asks, "Why does it work?"

The college graduate with an Accounting degree asks, "What will it cost to build?"

And the college graduate with a Liberal Arts degree asks, "You want fries with that?"

 

The one good thing I can say is that I managed to graduate with zero student debt, thanks to a Pell Grant and a LOT of hard work for min wage plus tips...

[MikeO89]

I don't quite understand why putting the mechjeb module in any certain place would affect the way it rolled. Most Command pods already have mechjeb built in so what then? If you had a 3 stage rocket that you wanted to control the stages independently when the stages separated, in that case you would have a mechjeb module on 2nd and 3rd stages and a built in one in the command module to control them separately. I don't see how placing the mechjeb module on a certain spot is going to change anything, unless I'm missing something.

 

El Sancho, the root part is the first part you start out with when building a rocket. Most of the time the command pod is selected as the first part but it doesn't need to be. As an example if you have the Blue Dog mod and you select that command pod as the root part, there are going to be problems later on in the mission with stuck rcs thrusters. But most of the time selecting command pod as root is fine. Also you can change the root part in the VAB.

Edited June 4, 2018 by MikeO89

[Gordon Dry]

6 hours ago, Gilph said:

but still had a large horizontal speed

Yesterday I had a lander on Mun using #801 with a horizontal speed lower than 1 m/s, so I guess either you had bad luck or your initial orbit was too much for MJ's algorithms.

I prefer to circularize to about 70 km around Mun before I even think of starting a landing approach.

[Westrum]

Sorry if this seems stupid, but I cant seem to get extend antennas and solar panels to work  I press the button, nothing happens. 

[El Sancho]

" Most Command pods already have mechjeb built in "

With all due respect, that statement is simply not true unless you're using a mod to make it so.

 

"Also you can change the root part in the VAB." 

Really? How does one go about that? I see the 4th tool button, marked Tool: Re-Root, but selecting it gives a message "select a set of two or more parts to re-root" which doesn't seem to make much sense...

Edited June 5, 2018 by El Sancho
for the children

[Gordon Dry]

8 minutes ago, El Sancho said:

I see the 4th tool button, marked Tool: Re-Root, but selecting it gives a message "select a set of two or more parts to re-root" which doesn't seem to make much sense...

Your're right, that never made sense.

I use

which by default changes that behaviour.

After choosing the 4th buttom from the left to re-root just click the part you want to be the new root and that's it...

[MikeO89]

As far as I know, if mechjeb is installed, most command modules are mechjeb enabled if you have at least one pilot in the CM. Highlight your cm in the VAB and the info will show if it's mechjeb enabled or not. The mod MechjebforAll I believe enables mechjeb in the cm even if there is no pilot.

 

Yeah the wording is a little weird in the reroot. Just click the reroot button, click on the part you want to change the root part to and then just click it again. Changing the root part can be rather useful on those times when you have a rocket already built and then want to change something. Sometimes getting back to that part to change can be a pain. Changing the root part in that situation can be useful to get to that part easier. Another good use of changing the root is for a subassembly for some sections you have just right and don't want to have to build again from scratch if you want to use it later. You can't save the root part to a subassembly. Changing root in this case lets you then select the assembled parts you want and save to a subassembly. Subassemblies have saved me a lot of time like when I have built another section a space station to send up and had the whole booster section already saved as a subassembly. Pop that sucker on and rock!

Edited June 5, 2018 by MikeO89

[El Sancho]

7 hours ago, Westrum said:

Sorry if this seems stupid, but I cant seem to get extend antennas and solar panels to work  I press the button, nothing happens. 

I too have encountered occasional flakiness with that feature. On the Utilities window, right? Most of the time it works fine for me, but sometimes it doesn't. With occasional odd stuff, I just figure my design is to blame, and don't worry about it...

[Gilph]

14 hours ago, Gordon Dry said:

Yesterday I had a lander on Mun using #801 with a horizontal speed lower than 1 m/s, so I guess either you had bad luck or your initial orbit was too much for MJ's algorithms.

I prefer to circularize to about 70 km around Mun before I even think of starting a landing approach.

True...the initial orbit was a bit non standard, but it highlighted issues with this approach to landing.  I read through the changed code and the comments a bit, and unless I misread it, there can be problems. I have also successfully landed vessels with 801 that did have RCS and found it very awkward.

Firstly, RCS is really needed for docking. A user used to be able to select whether RCS is used for landing, but it enabled automatically in 801. If I needed to save my RCS for docking on return, and it all got used up on landing, I'd be in trouble. Also, when I touched down, all these attitude control screens popped up and I'd have to go and disable and close them, which is a bit tedious. I really did not need any of that enabled.

I know the problem of eliminating that last fraction of horizontal speed was difficult sometimes, causing vessels to flip wildly to zero it out. But I think these new approaches need to be selected as options, and there needs to be an additional check to see whether the vessel actually has RCS thrusters, and if so, the user enabled them to be used.

[bartekltg]

12 hours ago, El Sancho said:

"Also you can change the root part in the VAB." 

Really? How does one go about that? I see the 4th tool button, marked Tool: Re-Root, but selecting it gives a message "select a set of two or more parts to re-root" which doesn't seem to make much sense...

You have to click on two different parts, the second one will became the new root. 

I do not understand it eithier, but this bu.. feature is in the game as long as i rember.

[Gordon Dry]

2 hours ago, Gilph said:

If I needed to save my RCS for docking on return, and it all got used up on landing, I'd be in trouble.

True

[El Sancho]

22 minutes ago, Gordon Dry said:

True

in reply to gilph who said...If I needed to save my RCS for docking on return, and it all got used up on landing, I'd be in trouble.

 

Just as a temporary workaround, I'd remind you that you can lock a tank or battery by clicking at the right end of the bar. It will change from a green triangle to a red circle-and-slash to show locked.

 

(Ugh, patch day in an MMO that shall not be named, but which is based upon a TV show of the notoriously split infinitive. Been patching half an hour now, and only at 11%. There are things I really miss about living in the States, like Trader Joe's, Huevos Rancheros with rice & beans on Sunday morning, and decent net connections...)

Edited June 5, 2018 by El Sancho
la pesada herencia del Kirchnerismo

[dlrk]

On 2.7.0 , is there a way to change default settings? I'd like to change the default touchdown speed and have differential throttle default to on