Throttle Stuck On stock Vector Engines when attempting to land booster

[dustinthenow]

I’m attempting space X style landing with booster. I’m using stock vector engines (tweakscale mod to fit 9 engines on booster) and mech jeb, along with reusablity mod with landing legs and grid fins. Throttle works until about 1 km above the ground?

Is there anyway to fix this? 

[4x4cheesecake]

Welcome to the forum

Do you lose CommNet connection or run out of (electric) engery?

[dustinthenow]

44 minutes ago, 4x4cheesecake said:

Welcome to the forum

Do you lose CommNet connection or run out of (electric) engery?

Thanks!

And, I don’t think so. The landing legs automatically deploy with Mech Jeb, but the landing burn won’t happen. I’ve tried doing the landing on my own, and the engines won’t reignite either, when it’s time to do the landing burn. I usually hit the ground going 320 m/s!

Edited August 29, 2018 by dustinthenow
Typo

[4x4cheesecake]

Hm...I'm not familiar with MechJeb. Maybe something goes wrong during the automatic landing and it overrides your own inputs? Do you hear any sounds when you try to throttle up which may sounds like starting engines which turns off immediatly again?
Is it just the throttle which is stuck or do you loose any controls like turning SAS on/off, WASD controls and so on?

 

[dustinthenow]

Hmm at first glance I would think it’s a mech jeb Issue, however the same condition takes place when I attempt to do a landing burn on my own. One Item to note, is the moment the issue starts, Mech Jeb auto landing will say on status: “Breaking: Target Speed = NaN m/s”

[Gargamel]

2 hours ago, dustinthenow said:

Mech Jeb auto landing will say on status: “Breaking: Target Speed = NaN m/s”

Okay, that's an issue.  You might want to post that in the MJ thread, and post your logs there too.  Sarbian, et al, would most likely be happy to help, but they're particular about having logs to work with, and I don't blame them.

But, since it occurs under manual control too, the root of the problem is not with MJ.  Unless of course, you have some feature of MJ enabled somewhere that is preventing the engines from firing, which can happen.    Turn off the landing control, and try to fire the engines.  If they're not working, click the MJ drop down tab.  Any MJ features that are currently active would be highlighted in green, if there are any, click those and disable them if needed.

My first reaction to this issue is, though, are you staging anything?  If a throttle is non responsive, and you have control of the vessel, you might have disconnected the engines somehow.   Or under a action group, disabled them.    But if that isn't the case, then you probably have something in MJ preventing you from throttling up.  

 

Oh.... you have enough fuel right?  And EC to control the craft? 

 

A pic might help so we can eliminate any design errors. 

 

[dustinthenow]

1 hour ago, Gargamel said:

Okay, that's an issue.  You might want to post that in the MJ thread, and post your logs there too.  Sarbian, et al, would most likely be happy to help, but they're particular about having logs to work with, and I don't blame them.

But, since it occurs under manual control too, the root of the problem is not with MJ.  Unless of course, you have some feature of MJ enabled somewhere that is preventing the engines from firing, which can happen.    Turn off the landing control, and try to fire the engines.  If they're not working, click the MJ drop down tab.  Any MJ features that are currently active would be highlighted in green, if there are any, click those and disable them if needed.

My first reaction to this issue is, though, are you staging anything?  If a throttle is non responsive, and you have control of the vessel, you might have disconnected the engines somehow.   Or under a action group, disabled them.    But if that isn't the case, then you probably have something in MJ preventing you from throttling up.  

 

Oh.... you have enough fuel right?  And EC to control the craft? 

 

A pic might help so we can eliminate any design errors. 

 

Thank you for the in-depth response, I will also post this in the mech jeb forum. Do you know the proper page to post?

A commonality is if I use mech jeb at all for landing, it will do this. (It hasn’t always done this though as other designs have landed fine).

I have an action group to replicate the 3 engine burn and the single engine burn, however what’s funny is there has been times where the rocket will crash, and If the engines survive, they will actually start to burn at full throttle! 

One thing to note, is you can still see the contrail of the engines, because one thing to note is they come on for a second and then shut down. 

I’ll post an image in a later post, as I can’t post an image while using the mobile site. (I think) 

[dustinthenow]

I've seemed to run into another issue - can't seem to attach my screenshot! It's ashamed. This may be helpful lol

[4x4cheesecake]

16 minutes ago, dustinthenow said:

I've seemed to run into another issue - can't seem to attach my screenshot! It's ashamed. This may be helpful lol

You have to upload the picture to an image hoster and post the link here:

 

[dustinthenow]

https://imgur.com/a/8E7UPJZ -- Image

[dustinthenow]

Great NEWS! I think I figured it out. The issue actually lies in the accent autopilot conflicting with the landing autopilot. 

Long story, short I just needed to turn off “Limit Q” for landing in the Utilities Window and everything worked perfectly.

Essentially what is happening, is when I’m hitting thicker atmosphere, the throttle is cut to prevent increasing dynamic pressure “Q” however it’s comfused because the accent autopilot is mistaking accent for decent. Ironically employing the engines during landing is exactly what is needed to reduce dynamic pressure! 

Thanks for all your help! 

[Gargamel]

Yup.  MechJeb is notorious for having conflicting controls activated.  When it goes wonky on you, check all your settings....

In this case, turn off the ascent guidance!!  As soon as you reach orbit, make sure that is disabled, not just the Q limiter.  

In fact, Limit Q is also found under utilities, and if you enable it under ascent guidance, it also is enabled under utilities.   Anything enabled in utilities will still function even if the ascent guidance is turned off.    Including things like throttle and acceleration limiters. 

Edited August 30, 2018 by Gargamel