Switching engines in flight?

[strider3]

I have been struggling to build a craft that can land on Laythe (see below). "Verticals" require too much fuel/oxidizer weight so I'm trying to take advantage of an air breathing engine to get me closer to orbit. Below is a picture of a modified stock VTOL I'm playing with (it's nowhere near done yet, so be kind ). My thought is to use the Twitches to get a vertical rise off the surface, then the Wheesley to fly forward (there will be wings and rudders, eventually) and the Terriers to get into orbit and dock. My first question is how do you swap between the Twitches to the Wheesley...then to the Terriers? I have no idea how that can be accomplished. How do you shut down 12 Twitches (12 might be overkill, at this point)? I currently have to click each one and shut it down individually so that my throttle only controls the Wheesley...by that time I'll be crashed, me thinks? The problem I always run into, in any multiple engine construction, is how to enable, disable or "throttle limit" all of an engine group at once (that is an issue I have with any craft...not just this one).

I'm sure I'll run into other problems going forward...but for now...how does one go about switching engines, and their throttle controls, in flight?

[Fraktal]

Add the engines' toggle action to an action group in the VAB. You can then use the 1-9 keys to switch them on or off.

[antipro]

5 minutes ago, strider3 said:

How do you shut down 12 Twitches?

action group doesn't work?

[strider3]

2 minutes ago, Fraktal said:

Add the engines' toggle action to an action group in the VAB. You can then use the 1-9 keys to switch them on or off.

OK, I'll try...action groups have been...hard for me to understand, exactly.

Just now, antipro said:

action group doesn't work?

See above...LOL!

Yeah, I have no idea how to use action groups. Anybody know of a detailed tutorial on that?

[Fraktal]

It's not that hard. Any action you put into a numbered action group (you need level 3 VAB/SPH) is executed each time you tap the corresponding number key on your keyboard.

For example, all of my aircraft have the 1 key as an engine master switch. On my first interplanetary craft, I set both the orbiter and the lander to toggle their engines with the 1 key, then light up the orbiter's engine via stating, so that the key now alternate between the two sets of engines. Back when I built my first SSTO, I had an action group toggle between the main engines and the Puff VTOL engines.

Edited December 18, 2020 by Fraktal

[strider3]

@Fraktal Thanks, but...I'm going to need way more detail on the "how to" on action groups. More of a step-by-step thing..."Click this, enter that, select this".

[antipro]

8 minutes ago, strider3 said:

More of a step-by-step thing..."Click this, enter that, select this".

Result:

[strider3]

And the key to use would be the "4" key? How do I select all my Twitches? In my screenshot you can see they are in batches of two's?

Edited December 18, 2020 by strider3

[antipro]

3 minutes ago, strider3 said:

And the key to use would be the "4" key?

yes, in this case I choosed the "4" key as an example, you can use from 0 to 9
and you can add more actions, like other parts/actions with the same key.

Edited December 18, 2020 by antipro

[strider3]

Just to make sure I'm thinking correctly...in the situation above I would have 3 keys, one each to "toggle" each engine group (Twitches - 1, Wheesley - 2 and Terriers - 3). To swap from Twitches to Wheesley I would hit key "1" then "2".

[Fraktal]

12 minutes ago, strider3 said:

How do I select all my Twitches? In my screenshot you can see they are in batches of two's?

If you added the parts to your vessel via symmetry, the action group will apply to all parts in the symmetry. In other words, you only need to add each Twitch pair once.

4 minutes ago, strider3 said:

To swap from Twitches to Wheesley I would hit key "1" then "2".

Exactly.

[antipro]

7 minutes ago, strider3 said:

I would have 3 keys, one each to "toggle" each engine group (Twitches - 1, Wheesley - 2 and Terriers - 3). To swap from Twitches to Wheesley I would hit key "1" then "2".

correct, or also you can bind the "toggle" action for both Twitches and Wheesley with the same key.
so, with one key pression you turn on one engines set and turn off the other set.

Edited December 18, 2020 by antipro

[strider3]

Years of KSP...and not knowing Action groups...sheesh!!

Thanks antipro! I see a lot of new abilities now!

Edited December 18, 2020 by strider3

[antipro]

5 minutes ago, strider3 said:

Years of KSP...and not knowing Action groups...sheesh!!

I have about 4k hours of play but still don't know a lot of things, ...it's rocket science.

 

8 minutes ago, strider3 said:

Thanks antipro! I see a lot of new abilities now!

you're welcome

[antipro]

@strider3 I forgot to mention that you can edit the "action groups" even while in flight