General [almost] Dragless Contraptions Thread

[Nazalassa]

Due to the way KSP handles aerodynamics, it is possible to create Dragless Contraptions^TM.

This thread is the general thread to discuss and develop Dragless Contraptions^TM.

I have recently made a Dragless Starship-like vessel:

{screenshot that I can't find goes there}

(show aero forces is on BTW)

Download it because why not

[Nazalassa]

I made that dragless SSTO today.

I guess that brings a new meaning to "Low Kerbin Orbit".

Edited March 6, 2024 by Nazalassa
Added download link (picture?)

[Nazalassa]

Since this thread seems to be some kind of repository for dragless stuff, I'm adding this extra bit of dragless science about making "drag flags":

18 hours ago, Lt_Duckweed said:

The key is setting the deploy limit on a service bay to one of the axis groups in the action group configuration.  While you cannot deploy a service bay while it is shielded, you can adjust the deploy amount, which results in it deploying.

The setup goes like this:

You have a root fairing whose base is shielded from solar heating by some other part that is larger than the base, but smaller than the overall fairing, so it can shield the base and be shielded in return.
In front of this, a structural plate or multiple structural plates have all drag cube faces fully occluded, creating perfect shock shields.
A service/payload bay is positioned such that the center of the bay is considered "inside" the fairing, but a substantial portion of the bay volume is actually located outside of the fairing.
A flag or flags of the largest size that the bay can shield are located in the portion of the bay that is outside the fairing.
If the flags are not located in the shock shadow of the main shock shield (as is the case for the main station) then a smaller shock shield(s) is constructed that sits immediately in front of the flags, but is also still outside the fairing.
Finally, the axis group chosen to control service bay deploy limit is adjusted to open/close the bays as desired.

 

Interestingly, there are a few other scenarios where you can use axis groups to perform actions that are normally forbidden via action groups.  Some examples:

1. Actuating service/payload/cargo bays when they are shielded.
2. Deflating an inflatable heatshield after it has already been inflated (can be done as many times as you like)
3. Deflating an inflatable airlock that already has a kerbal inside it.

[jounce]

The ssto speeder does not work,the orbiter does,but I could not get it to work again after dissassebling that fairing and then putting it back.

I'd assume that the fairing and the engine plate shield each other?

[Nazalassa]

6 hours ago, jounce said:

The ssto speeder does not work

The SSTO speeder is quite old and I can't test it right now, but that's weird. iirc it worked for me. Maybe try downloading it again?

6 hours ago, jounce said:

I could not get it to work again after dissassebling that fairing and then putting it back.

I'd assume that the fairing and the engine plate shield each other?

Indeed they do. Make sure the engine plate has its fairing enabled, else it won't shield anything.

Are you using FAR? In that case, both ships will likely not work, due to how FAR simulates shielding and aerodynamics in a much different way than stock KSP.

[jounce]

5 hours ago, Nazalassa said:

The SSTO speeder is quite old and I can't test it right now, but that's weird. iirc it worked for me. Maybe try downloading it again?

Indeed they do. Make sure the engine plate has its fairing enabled, else it won't shield anything.

Are you using FAR? In that case, both ships will likely not work, due to how FAR simulates shielding and aerodynamics in a much different way than stock KSP.

I dragged the fairing to the engine plate,so that it gets its fairing,then moved the fairing up a bit

I have LunaMultiplayer,MechJeb,and KER

5 hours ago, Nazalassa said:

The SSTO speeder is quite old and I can't test it right now, but that's weird. iirc it worked for me. Maybe try downloading it again?

Indeed they do. Make sure the engine plate has its fairing enabled, else it won't shield anything.

Are you using FAR? In that case, both ships will likely not work, due to how FAR simulates shielding and aerodynamics in a much different way than stock KSP.

Maybe the ssto speeder got corrupted by me trying to load it in 1.12.2 then failing and then updating the game

Oh,and the updated version still had all mods except Squad in 1.12.2,this includes the mods and the DLCs

Edited March 25, 2024 by jounce

[jounce]

Is able to replicate the Orbiter save

Connection:Fairing->Engine plate->Dart engine->rest of craft

Engine plate must contain fairing,dart must be mostly in fairing,rest of craft must be in fairing

https://kerbalx.com/jounce/umm-this-is-dragless

Edited March 26, 2024 by jounce