Hello,

So I've been noticing that a few engines from other mods do not allow thrust control by mechjeb unless they are accompanied by a compatible engine (like a stock one).

I've noticed this particularly with the LLL (Lack Luster Labs) Large Nuclear engines. Although, I think there may be a couple non-LFO engines in the Near-Future pack that have the same issue.

when a maneuver is executed, the ship lines up, warps to, and unwarps right at the node time (no lead time at all) and then fails to increase the thrust.
This is inconvenient because the thrust is also locked. which means I have to manually execute the nodes with A.S.S. help. (ugh the pain :P )

however, I have noted these engines do work in two situations:

1. when they are accompanied by a working engine
2. when landing guidance does the deorbit burn (suspicious) (but it doesn't work for the course correction in landing guidance)

mechjeb 2.1 (public release) KSP .22

Not intending to flog a dead horse here, but it seems to me there is still an issue here with MechJeb's auto landing feature. Whenever I try to land with a delayed-response LLL engine, the required thrust needed for the braking burn will be dramatically underestimated by MechJeb, causing me to crash into the surface at high speeds every time.

As a suggested work-around until a permanent fix, maybe it would be a good idea for MechJeb to actually suppress all engine response times while it is installed through a CFG addition along the lines of:

@part[ModuleEngines*]:FINAL {
@useEngineResponseTime = false
}

While this might come at a slight cost to realism, seing as the delayed thrust probably reflects a real characteristic of such engines, this could be viewed as a crude way of simulating that an automatic guidance system like MechJeb ought to have no problems taking such delays into account and compensating for them accordingly.

I talked to Lack, the issue is more specifically the inability to handle engines with delayed throttle.

i.e.
(this is what the specific engie has in the .cfg)

engineAccelerationSpeed = 0.5
engineDecelerationSpeed = 1.0
useEngineResponseTime = true

sorry for the vaugness...

this issue can be worked around by simply removing that code from the engines cfg files until MechJeb can handle them

Yes, engine with reponse time are a hard one for MJ but it should still try to trust.
I'll have to test it then.

I tried it out and can confirm that it works. but the first time i attempted a landing from mun orbit it overshot the course correction (bc delayed thrust continued after it shut down) and it just gave up i guess? i aborted and restarted the landing and it made the necessary adjustments and landed without a problem

Just did some test with my current version (with a bit more code than the latest dev version) and it works for large dv node. For smaller one the delay will most likely disturb node execution, but for now I don't see how to do better

Edit: I just hate you for reminding me how much I like LLL, and seeing that I can't add it to my current set of mod without crashing ! :)

Haha, the greatest KSP dilemma: "which mods can I live without"
I hear rumors that 64bit unity is going to come out in the next year... but I'm pretty sure WE NEED it now.

thank you, I'll download the latest dev? (http://jenkins.mumech.com/job/MechJeb2/) and try out a landing and node execution

You should get the one I added a minute ago