Devnote Tuesdays: The Greener Pastures Edition

[KerrMü]

Hey Rowsdower

You've been an awesome CM with commitment and almost supernatural patience. I hope to see you around the forum from time to time.

Good luck and may the force be with you (and greetings to her, too )

[federicoaa]

Felipe (HarvesteR): Last week, the new drag and lift models got integrated, and early testing has started on that. Early feedback sounds very good so far, and based on my own subjective experience, flying does feel a lot better now. We’re far from done though, as with the new changes, new possibilities arise and must be accounted for. Cargo bays haven’t had much of a use until now, but with the new aero system, they will shield whatever is inside them from the airstream. This means more than reduced drag and reentry heat though. Wing surfaces placed inside (closed) bays won’t function, neither will parachutes, RCS blocks, solar panels, air intakes or science experiments which must be performed in an atmosphere. To get those to work again, you will have to open the bays first. These parts which were mostly just for show so far should now become a much more important (and useful) consideration when building.

About fairings, I believe inline fairings will be better option than procedural fairings. What I am saying is to have cylindrical fairings for 2.5m and 3.75m where you attach the payload and put a nosecone or pod on top. IIRC KW has something like that.

Another thing, you mentioned that wings inside closed cargo bays would not have lift, but what about wings inside open cargo bays? They shouldn't work either. Could you clarify?

@Rowsdower: Good luck in your future endeavors, you are going to be missed.

[KarmaLarma]

Very sad to see you go, Rowsdower. Just like to say thanks for all that you've done for this community. You will be missed.

[tntristan12]

Yeah. Those vague comments alluding to partial occlusion made me nervous as well. I hope we don't have to take that to mean that only objects *inside* cargo bays are shielded. That hardly seems like an improvement, but perhaps I just misread.

[Alshain]

Another thing, you mentioned that wings inside closed cargo bays would not have lift, but what about wings inside open cargo bays? They shouldn't work either. Could you clarify?

I wondered about that too. If wings would work in an open cargo bay, that says would speak volumes about the (lack of) quality of this aerodynamics package. I certainly hope that is not the case, and it's just a stragely formed sentence.

[Yellowburn10]

Another thing, you mentioned that wings inside closed cargo bays would not have lift, but what about wings inside open cargo bays? They shouldn't work either. Could you clarify?

It's simple: Cargo bay closed, no air flow, wings don't work. Cargo bay open, air flows inside, wings work. Although they would only work to an extent I suppose.

[Ippo]

No, they shouldn't work. The wing pushes the air down and generates lift, the air hits the floor of the cargo bay and generates a downward force that cancels the lift.

[federicoaa]

No, they shouldn't work. The wing pushes the air down and generates lift, the air hits the floor of the cargo bay and generates a downward force that cancels the lift.

Exactly. Hope Harv clarifies on this soon.

[Frank_G]

Thumbs up for you Rowsdower! All the best to you, whatever comes and thank you for everything. Dont forget to stop by here from time to time

Awesome Devnotes! Sounds like things are coming together quite nice. I am really eager to peek, how everything looks and works now. Keep it going!

[Ikaneko]

See ya round, Rowsdower. It'll be hard to source a replacement who matches your tireless effort for the community.

I remember back in 0.25 (planes!) I started the HypePlane thread along with ZodiaK. It reached 6 pages before being abruptly locked by Kasper. I immediately sent a rather angry (but nothing rude) PM to Rows.

His response was balanced, reasoned, calm and even included an apology!

This is indicative of how excellent he was at CM.

[KerbMav]

Is that just going to an "If in cargo bay, then not working" fudge, or will RCS thrust actually be checked for being blocked like engine thrust is?

Uh-oh ... important question!

I wonder what the whole thing about wings being inside cargo bays not working until the bays are open means. Could you put a bunch of wings inside a cargo bay, be cruising along at 100m/s, open the cargo bay, and instantly have lift?

I think he's just demonstrating that things in cargo bays won't do squat.

In any case, the new lift system should stop that.

I hope we don't have to take that to mean that only objects *inside* cargo bays are shielded.

The RCS thing feels like a crucial point here.

If RCS is not blocked by walls/objects like the other engines, but do simply not work in a closed cargo bay, then I gather solar panels would work in an open cargo bay even if the craft has its ventral side oriented towards Kerbol/Sun - and the same for control surfaces/wings.

Also, will parachutes not open inside a cargo bay, their canopy be trapped inside or their canopy stick out of the craft but do nothing?

I think we expected the doors (and walls, like it is already) to block sunlight and the walls to still block airflow (part occlusion, necessary for streamlined forms working as such) even if the doors are open.

It's simple: Cargo bay closed, no air flow, wings don't work. Cargo bay open, air flows inside, wings work. Although they would only work to an extent I suppose.

It would be simply wrong.

[Seshins]

Good luck with your future Rowsdower, will be sad to see ya go. Great progress with the update team, im really looking forward to this.

[NathanKell]

Colliders already block sunlight for solar panels. You put a solar panel in a cargo bay facing down, it ain't gonna work. (AFAIK)

Lift, however...well, all indications are pointing to Squad uncoupling lift from drag, and them operating off different rules, with lift still being magical. So I'm going to guess that as soon as the bay opens, the wings start working. SOKERBAL.

If the wings *were* occluded, then the same thing would happen with tail surfaces behind a fuselage. Contrary to Max's assertions, air is not light and you can't model it that way (well, you can, but that assumes you're at like Mach 20). Rather than giving up the light model, though, sounds like drag is laserlike but lift is magic...

[regex]

but lift is magic...

mylittlepony.jpg

[KerbMav]

If the wings *were* occluded, then the same thing would happen with tail surfaces behind a fuselage. Contrary to Max's assertions, air is not light and you can't model it that way (well, you can, but that assumes you're at like Mach 20). Rather than giving up the light model, though, sounds like drag is laserlike but lift is magic...

All the more reason to not take Ferram as some conjurer of cheap tricks!

It is simply amazing how deep modders can - and are allowed to - reach into the guts of this game.

Thank you Squad, for the openess - thank you modders for all the gut-diving!

[OrtwinS]

Rowsdower, you will be hard to replace, and impossible to forget. I wish you good luck and happiness in your new ventures.

I share other peoples concern about the occlusion effects for lift, drag and thrust. Wings shouldn't work in a cargo bay, open or closed (or very weirdly when open).

Might I suggest you release the airo overhaul as 0.91 beta for thorough testing?

[basic.syntax]

Wings should be "disabled", if they have an attachment relationship inside a cargo bay. (The engineer's report might also note this, but the payload attached inside the cargo bay could be anything, so its not necessarily a problem.) You might want parachutes to work from inside a bay; but, parachute lines don't have collision. 'Chutes always work, and don't wrap around objects or tear. Coding physically modeled parachutes that believably interact with other parts, would probably be a headache, and a new CPU hit, so I wouldn't expect it.

An OPEN cargo bay should increase drag, by a large amount.

HarvesteR focused on cargo bays in this week's note, but don't worry about things not mentioned, like nose cones and fairings. He was explicit about all three types of parts in the article about Aero overhaul.

The main goal of a new drag model then, is to allow the game to properly simulate payloads being protected from the airstream by a cargo bay or fairing, and nose cones properly reducing the drag of parts stacked behind it.

[LordFjord]

Good luck Rowsdower, I hope we keep you around as a KSP player.

And to toss some fuel into the cargobay discussion fire:

"what if" I have an upside-down cargobay that is open on both ends - like a tube - and some wings inside... aerodynamic shenanigans incoming... cause why not?

[CaptRobau]

Have a good life Rowsdower. Hope to see you around the community from time to time.

[Dodgey]

So long and thanks for all the fish Rowsdower, hope you have a good one .

[micha]

No, they shouldn't work. The wing pushes the air down and generates lift, the air hits the floor of the cargo bay and generates a downward force that cancels the lift.

<offtopic>

Umm, actually, no. At least, not once you get to any appreciable speed.

The reason wings are cambered are so that the air has a longer path over the top of the wing than underneath. Ie, the same amount of air has a further distance to travel in the same amount of time. Hence the air on top of the wing is less dense than the air underneath the wing, effectively sucking the wing (and whatever it's attached to) up.

However, they still shouldn't work (much) since even with the bay doors open, the contents would still be mostly shielded from the airflow.

</offtopic>

@Rowsdower: I haven't been around or active enough to really appreciate your hard work, but so long, and thanks for all the fish^H^H^H^Hboosters! Best of luck in your new endeavours!

EDIT: Eh, ninja'd by dodgey using that line.. oh well.

Edited February 4, 2015 by micha

[KerbMav]

.

For this to work the airstream would have to enter the cargo bay to get to the wings in the first place - and there are good reasons we build planes sleek and with as few "holes" as possible.

The camber also does not generate lift, it reduces the drag.

So, even the theoretical lift (not existant as you imagine) from the wings inside the bay would be opposed by many different effects on the plane because of the open space inside its body.

https://www.mansfieldct.org/Schools/MMS/staff/hand/flightcamberedwings.htm

http://flighttraining.aopa.org/magazine/2004/November/200411_Features_Camber_is_the_key.html

Edited February 4, 2015 by KerbMav
corrected my science!

[Linear]

Good luck Rowsdower - you were a good man.

[cantab]

I think it reasonable to expect the following:

Parts in a closed cargo bay have no aerodynamics, period. No lift, no drag. There might be a requirement for the ends to be covered up too.

Parts in an open cargo bay will be subject to normal aerodynamics. That the cargo bay is near to them means they probably won't create the full lift or drag you would expect, but there will still be forces going on.

[Potatocan]

Yay better aerodynamics! ������