Max Q

[Hatsune]

I don't have MJ, so I could not measure the dynamic pressure of the vehicle and know when to throttle down. Could anyone tell me when to throttle down for max Q? Currently I just fly to 10km and throttle down until 18 and go back to full.

[Jestersage]

In a way, there are no actual MaxQ in stock/MH KSP, simply because the components only have to think about drag and Heat - not structure load (even if you do not bother autostrut). Actual MaxQ is all about the structure load pressure.

The reason we throttle down is to minimize heat, as well as use fuel efficently. Typically just keep TWR at around 2 at less than 50k, and 0.6~1+ above 50k, and you will fly efficiently.

As far as I know, drag does not increase with more TWR.

Edited April 9, 2019 by Jestersage

[FloppyRocket]

In the Debug menu, you can enable the "Aero GUI", and you can see the drag and pressure values during launch.

It's available in the stock game, you don't need any mods.

"Q" refers to dynamic pressure, the Aero GUI displays it.

I agree with @Jestersage, dynamic pressure is not the only thing you want to monitor to reduce heating and drag.

Edited April 10, 2019 by FloppyRocket

[Aegolius13]

If you're rocket's not flipping or blowing up, you probably don't need to throttle down at all.  Drag losses should also be pretty minimal unless you're flying a brick. 

 

This thread is really informative: 

 

[Hatsune]

3 hours ago, FloppyRocket said:

In the Debug menu, you can enable the "Aero GUI", and you can see the drag and pressure values during launch.

It's available in the stock game, you don't need any mods.

"Q" refers to dynamic pressure, the Aero GUI displays it.

I agree with @Jestersage, dynamic pressure is not the only thing you want to monitor to reduce heating and drag.

where can I find aero GUI?

[bewing]

1 hour ago, Hatsune said:

where can I find aero GUI?

Alt-F12 to bring up the Debug menu. Then look under the Physics/Aero tab, and check the box for "Display Aero Data GUI".

[Hatsune]

10 hours ago, bewing said:

Alt-F12 to bring up the Debug menu. Then look under the Physics/Aero tab, and check the box for "Display Aero Data GUI".

I presses alt+f12 and nothing shows up

[FloppyRocket]

2 hours ago, Hatsune said:

I presses alt+f12 and nothing shows up

Alt is the "Mod" key on Windows. Your "Mod" key may be different, depending on your computer operating system.
 

[Snark]

22 hours ago, Hatsune said:

I presses alt+f12 and nothing shows up

Possibility #1, if you're not on Windows, you'd need a different key.

Possibility #2, if you're playing on Steam, I believe that Steam uses alt+F12 by default for its own purposes, which can get in the way.  Easily solvable by going into Steam and re-mapping their whatever-it-is function to some other key, or else by simply playing KSP directly rather than using the Steam launcher to play it.

[bewing]

I think it's more the NVidia Geforce Experience background app that swallows Alt-F12 for players that have it installed.

Edited April 11, 2019 by bewing

[Hatsune]

46 minutes ago, bewing said:

I think it's more the NVidia Geforce Experience background app that swallows Alt-F12 for players that have it installed.

I think so.

On 4/9/2019 at 3:52 PM, Jestersage said:

Typically just keep TWR at around 2 at less than 50k, and 0.6~1+ above 50k, and you will fly efficiently.

That is probably why. I always add moar engines and the vector spam always make my TWR to 3.