Producing lift on wingless bricks! for SCIENCE!

[SnakyLeVrai]

Fellow Kerbals and Kerbalinas,

Did you know you could produce LIFT to direct your capsules during reentry? WONDER NO MORE! I tried and confirmed it in KSP... FOR SCIENCE!

(click for larger)

This is an experiment (with 1.0.4) inspired by

(among others).

You can achieve this by slightly offsetting the center of mass of the capsule, so the airflow acts in an asymetric way, thus producing lift. This helps during reentry if you notice you are going to land on an ugly mountain and wish to veer away, but have long jettisoned any engine that will give you the push you need.

Check the gallery for blueprints and commented results!

 

Have a good flight!

Snaky (le Vrai)

Edited December 24, 2015 by SnakyLeVrai
typos

[paul23]

Hint: press f12

[SnakyLeVrai]

hmm yep, why, aero forces aren't showing up correctly? I alt-F12 and checked aero forces specifically for those pics.

[Johnny Wishbone]

This is an experiment (with 1.0.4) inspired by

(among others).

Anyway, I thought someone already figured this out back when 1.0 came out. The new aero model actually allowed you to roll the capsule (just like Apollo) during re-entry and thereby create lift (and drag) and alter your reentry trajectory. As you discovered, and just like the real thing, you need to change the CoM of the capsule in order to do this, but yes, it is possible.

Edited November 18, 2015 by DuoDex

[wossname]

She done a book too. With pictures. Hoping to buy one in January.

Edited November 11, 2015 by wossname

[DancesWithSquirrels]

I tried that early on in (IIRC) 1.0.2, based on what I believe was a Scott Manley YouTube episode using the Ferram Aerospace mod. Took a Mk1-2 pod with a pair of half-empty Stratus-V round tanks near the top and transferred monoprop back and forth - definitely develops lift when the CoG isn't on the aerodynamic center.

Didn't make measurements, though, and if I took it too far the exposed mono tank exploded, so I didn't take it much further.

[Brainlord Mesomorph]

But can't I do that just by angling the ship with SAS?

[SnakyLeVrai]

But can't I do that just by angling the ship with SAS?

Of course, you definitely can, provided SAS packs enough torque to maintain you in your desired AoA

The problem is to maintain a heavy ship in position at hypersonic speeds, meaning you have to counter the immense torque produced by asymetric drag at ludicrous speeds. SAS is very, very weak for heavy ships. With this particular ship in my bluprints, the biggest SAS module wouldn't hold it at all under 30-40km if I recall correctly - the ship's mass is slighty above 10 tons.

Additionally, I tend to develop my ships in a way that they show some stability even in the case of total electrical failure. Every capsule or spaceplane I make has the ability to come back home safely even if I have lost all power they will ALWAYS have the good AoA.

unfortunately... it seems that 1.0.5 aero & thermal tweaks will overheat any ship easily... I'll have to make some trials and make adjustments to my launchers, spaceplanes, capsules...

@DancesWithSquirrels: yeah I experienced that problem too when I accidentally offset the CoM too far ahead. It was flying at a 100° AoA (instead of 160° like depicted in my results), so it was quite... inconvenient All you had to do was to fill the Stratus-V with a tiny, tiny amount more than the other, instead of 0% one and 100% other.

[Pecan]

hmm yep, why, aero forces aren't showing up correctly? I alt-F12 and checked aero forces specifically for those pics.

No idea if anything is wrong, but "alt-F12" is different to "F12"

[cantab]

Yup, works pretty well in KSP. At least in FAR, and probably newstock too. And if it's just a bare pod you can generally use the magic of reaction wheels.

I don't find it that useful for making the re-entry more gentle, but it can work to fine tune your landing site.

[A_name]

Ahh....The KSP forum's favorite plagiarist (who gets a free pass because she's "cute"). Ok, ok. Settle down; that was uncalled for, I know.

Whaaaa? What are you talking about there mate?

[S1gmoid]

Heya... I've been thinking about adding the ability to offset CoM to some capsules and experimenting with this... is there an existing mod that does something similar?

[Workable Goblin]

[quote name='A_name']Whaaaa? What are you talking about there mate?[/QUOTE]
[url=http://www.thespacereview.com/article/2394/1]This[/url].

[NathanKell]

RO has had offset capsule CoMs for...basically ever. It uses the plugin asmi wrote for BobCat for his Soyuz, more or less.

[S1gmoid]

Hey thanks for the info Nathan. :) I'll look into it. By the way, is it toggle-able in RO, or do you have some mechanism to adjust for off-center mass during launch and burns?

[NathanKell]

It's a plugin that toggles the CoM Offset, yes. Called "Descent Mode" ingame.