Devnote Tuesdays: The Aerodynamic Edition

[Bill Phil]

Why care so much about the aero model? At least it's getting done! That's the problem with a bunch of mod players. They get over-saturated with their way and start to think that's how the game should be. Not to say that ALL mod players are like that...

I'm mostly a stock player, but that's because my computer probably couldn't handle all the mods. But this gives me a more respectful posture towards Squad.

Enough said.

[Torquemadus]

Another point that needs to be raised is how better SSTO spaceplane performance will be balanced against the economics of expendable "trash bins full of boom" solid rockets in the upcoming balance pass.

My current launch vehicle families make extensive use of fully expendable all-solid first stages, due to their low costs. Solid rockets are cheap, and are worth next to nothing when empty, which allows for guilt free dropping of spend solids after staging.

Will solid rockets remain useful as expendable first stages in the next patch?

[Motokid600]

Another point that needs to be raised is how better SSTO spaceplane performance will be balanced against the economics of expendable "trash bins full of boom" solid rockets in the upcoming balance pass.

My current launch vehicle families make extensive use of fully expendable all-solid first stages, due to their low costs. Solid rockets are cheap, and are worth next to nothing when empty, which allows for guilt free dropping of spend solids after staging.

Will solid rockets remain useful as expendable first stages in the next patch?

That depends on how the new aero model effects the dV to orbit. With FAR SRBs are very, very practical. A light payload can be put into orbit in a single stage ( liquid fuel, you'd need atleast two srbs to achieve orbit in FAR.. Maybe not the larger ones ). Part of the reason why FAR knocks off 1k dV to orbit is the ability to perform an actual gravity turn. So if this next update allows for real gravity turns then SRBs will become even more economical.

That being said I think people are going to have to accept the fact that dV to orbit is going to be significantly less. If the new aero model is correct then it should be. I don't particularly have a problem with that. It's more realistic to have two-three stage rockets. Hell the Atlas rocket that put Mercury into orbit was practically ssto. So FAR's dV numbers are pretty close to what they should be imo.

Edited January 14, 2015 by Motokid600

[Red Iron Crown]

Just curious, how much fuel to you waste either going so slowly that you're burning really far upward, or fighting air resistance because you're going really fast for your altitude? Or have you found a way to follow a 3rd option that I can't think of? I'm honestly curious, as I tried to do "real" gravity turns in stock and found them too damaging to my dV.

When doing a "proper" gravity turn I spam the bottom of the rocket with aerodynamic surfaces and do a small eastward turn once I hit 100m/s or so (>5 degrees) and then modulate the throttle to stay below terminal velocity if necessary, though it generally isn't necessary as I like lowish initial TWRs of around 1.3. The aero surfaces keep the rocket pointed prograde until the atmosphere gets thin, then I use the SAS to stay that way right up until circularization. This technique can be made to work, but it is very sensitive to the magnitude of that initial turn.

That said, it is more efficient in stock aero to wait until 8km or so to start turning and I usually do so, but the difference is not large. I was more responding to the "ascend to 10km and crank it 45 degrees is the standard stock aero gravity turn" comment, which is false. Sharp turns are almost as bad an idea in stock as they are in NEAR/FAR.

[Kerano]

Fantastic update. Looking forward to seeing how the new aerodynamics model turns out.

Some kind of tool to estimate how well a plane will fly inside the hangar would be invaluable. Even knowing about the center of lift and mass buttons, it sometimes takes me hours to tweak a brand new design to fly as well as I want it to.

Pleased to hear that cargo bays and nosecones will have an actual purpose. You mentioned balancing this with the desire for crazy ship designs to still be able to fly though (albeit inefficiently). Maybe one way of achieving this would be that instead of penalizing non-aerodynamic designs, they could fly similarly to how they did in the past - but aerodynamic designs would get a bonus in terms of reduced drag. Not sure how this would work out in practice, but it sounds good in my head anyway.

Nice that lift will be proportional to velocity squared, should make for more fun flying at high speeds.

Marco (Samssonart): Still working on the demo. Last week was more about planning how the demo will work, what features must be included, which ones have to be out and which ones will make it in, but in a more basic way. I did get started on it, but haven’t actually done much yet. It’s just that the design part absolutely had to be clear in order to start the actual work.

You may have already discussed this, but regarding contracts - it seems a good idea to at least give a "taster" of them in the demo. Maybe limit them to only generating on Kerbin... possibly the Mun and Minmus, definitely nothing outside the Kerbin system. And only use a subset of the contract types - definitely rule out asteroid redirect, probably bases and space stations, maybe satellite delivery. At a minimum level you could just have part tests and perhaps Kerbal rescues.

Max (Maxmaps): .Plans laid, tasks assigned, we ended week one at full steam ahead. Aerodynamics has dominated discussion at the office even throughout its coding and implementation, once all was done, I spent my week setting up business calls and enjoying meetings with partners for cool projects we’re trying to develop. Putting all that aside, I had a ton of stuff to follow up on regarding Mr. Musk’s kindness and his mentions of KSP in that terrific AMA he did.

Hints of SpaceX related parts/missions in the future, perhaps?

[basic.syntax]

Hints of SpaceX related parts/missions in the future, perhaps?

Give us an autopilot that can keep engines running and nearly orbit the ship, while we toggle back to our first/second stages, to guide them to safe landings on a postage-stamp-sized barge floating in the ocean. What could go wrong?

[Loligoat]

This sounds like it's going to be yet another great update. I played with FAR for some time, and while I enjoyed it, after a while I started to get bored with having to test my designs over and over and get every part of it just right. This new system sounds like it will be a fair balance, although there may be some who might disagree.

As for favorite non-KSP youtuber, I couldn't decide between them, so I'd just have to say the Mindcrack group. They started just playing Minecraft, but over the years they've acquired more members and started playing different games on their channels. They're all unique and entertaining personalities, and you couldn't ask me to pick an official favorite.

Don't tell anyone but I might like Kurt more

[NoMrBond]

Give us an autopilot that can keep engines running and nearly orbit the ship, while we toggle back to our first/second stages, to guide them to safe landings on a postage-stamp-sized barge floating in the ocean. What could go wrong?

I was hoping for a downrange barge (as a purchasable facility) which also operates as a landing zone with increased recovery %

[Agost]

Just integrate FAR if the developer agrees

...

profit

[politas]

As far as t-shirts go, could you please move from Cafepress to literally any other site that does t-shirts? Cafepress'limitation to only white shirts makes your offerings really unappealing.

[TMS]

I was hoping for a downrange barge (as a purchasable facility) which also operates as a landing zone with increased recovery %

Heh, that's an interesting idea for a commercial tie-in.

[tuckjohn]

Jim (Romfarer):We are also looking at ways to improve the whole CoM/CoL trick to gauge the stability of airplanes. What it will look like, i really can’t say, because it’s still on the drawing board. Feel free to add your ideas in a reply.

How about an aerodynamics window, like FAR, but simplified?

Anthony (Rowsdower):Who’s your favorite non-KSP YouTuber? Any game.

Scott Man...Oh non KSP? Right: I would have to say I really like NerdCubed and BdoubleO100

The former plays a lot of indie games, and rarely does series (every video is typically on a different game)

The later plays a lot of Minecraft.

[sdj64]

A Center of Drag button would go a long way to help make our crafts more stable. A good extension of this would be to have an option in the SPH and VAB to set the airflow direction and have the Center of Lift and Center of Drag change to reflect that. I'm imagining a fifth editor tool for this that overlays translucent arrows through your craft (only when it is active) and has a rotate tool similar to the existing one, positioned at the center of mass of the craft that allows you to rotate the airflow arrows to whatever angle you want.

Just speculating, but I think that mach effects will not be modeled and it will be more like NEAR. That way you could avoid the mach effect graphs in FAR. The Center of Drag button combined with the Airflow Direction would be better IMO and more intuitive than the FAR graphs anyway.

[Starwhip]

I realize that when I post this, half the forum is going to think that the new Devnotes have come out.

Well, I have one thing to say: It should be coming out soon, because Today is Tuesday!

[Whirligig Girl]

I realize that when I post this, half the forum is going to think that the new Devnotes have come out.

Well, I have one thing to say: It should be coming out soon, because Today is Tuesday!

Y U Do Dis, Starwhip.

[RocketPilot573]

I realize that when I post this, half the forum is going to think that the new Devnotes have come out.

Well, I have one thing to say: It should be coming out soon, because Today is Tuesday!

What have you done.

[Pecan]

Huh? Today is Wednesday, by two whole hours.

[Starwhip]

Huh? Today is Wednesday, by two whole hours.

Time zones, my friend, are confusing.

[Specialist290]

Real cute there, Starwhip To avoid confusion with this week's scheduled devnotes, it's probably wise to go ahead and lock this thread up before the waves of fan outrage sweep over you.