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[1.3.1] Ferram Aerospace Research: v0.15.9.1 "Liepmann" 4/2/18


ferram4

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@White Owl & Weatherman159: I have confirmed the "issue" which turns out to be the result of an undocumented change: I had been updating the lift and drag of blunt bodies and had not realized that a version of this was in the current version. I've tweaked things a little bit here and I'll have to do some more testing to make sure that nothing truly silly happens.

@Playful1510: The Flight GUI is powered by command pods and probes, so if you're focused on a vessel without one of those you won't see it. An alternative is that the window is being displayed off the screen; if that is the case, then deleting the file in GameData/FerramAerospaceResearch/PluginData should fix it.

@NathanKell: Yeah, that's a known issue with how drag is calculated. Basically, the larger part thinks that its blunt end is completely covered when it isn't. Hopefully I can come up with a solution to that soon.

@Dexee: I doubt anything FAR uses would have been broken between 0.21 and 0.21.1. FAR isn't as intertwined as some of the other mods are with KSP's code, so minor changes (of the type that would happen in a KSP hotfix) shouldn't change anything at all.

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By the way, I posted this in another thread but didn't realize there was a thread dedicated to FAR here. Here goes again:

So I have FAR and DeadlyReentry installed, and surprisingly, since many people say that combination makes reentry way too hard, I think it is instead way too easy.

I am finding myself able to withstand reentries in excess of 3300m/s without any heat shielding whatsoever, temperature never goes above 680C, and barely any g-loading.

The issue is that FAR makes the command pod have way too much lift, so I can literally fly the pod and stay above 28km until airspeed is well below 700m/s.

I am using ksp 0.21 and FAR 0.9.5.3. I believe the issue was present in 0.20.2/0.9.52, but the old SAS meant that flying it was too hard because the capsule would spin around while you tried to work the pitch.

The capsule is even flyable at very low airspeeds.

I made a video demonstrating how easy it makes doing a precision landing with the capsule.

Edited by mizo
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By the way, I posted this in another thread but didn't realize there was a thread dedicated to FAR here. Here goes again:

So I have FAR and DeadlyReentry installed, and surprisingly, since many people say that combination makes reentry way too hard, I think it is instead way too easy.

I am finding myself able to withstand reentries in excess of 3300m/s without any heat shielding whatsoever, temperature never goes above 680C, and barely any g-loading.

The issue is that FAR makes the command pod have way too much lift, so I can literally fly the pod and stay above 28km until airspeed is well below 700m/s.

I am using ksp 0.21 and FAR 0.9.5.3. I believe the issue was present in 0.20.2/0.9.52, but the old SAS meant that flying it was too hard because the capsule would spin around while you tried to work the pitch.

The capsule is even flyable at very low airspeeds.

I made a video demonstrating how easy it makes doing a precision landing with the capsule.

Video is ATM private...

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@White Owl & Weatherman159: I have confirmed the "issue" which turns out to be the result of an undocumented change: I had been updating the lift and drag of blunt bodies and had not realized that a version of this was in the current version. I've tweaked things a little bit here and I'll have to do some more testing to make sure that nothing truly silly happens.

Excellent news! I hate to bring any complaints, but I'm so happy the problem is fixable. Playing KSP without FAR is just intolerable now. Using the stock aerodynamics would be like putting training wheels on a racing motorcycle.

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@ferram, ah, I see. Yeah, it would be wonderful if you could fix that. I can't be the only person getting into Mission Controller and wanting to _safely_ deorbit spent stages!

One other thing, while I'm asking. Parachutes. I know you're leaving them alone for now, and that's fine...while they're extended. But adding a single Mk16 (that is to say, launching a one-kerbal pod) to a rocket will triple its drag losses. I even went ahead and set stowedDrag to 0 for all parachutes, and I'm _still_ getting 50+ m/s drag from a single undeployed chute on ascent. Can you kill stock drag for parachutes but only when undeployed, or something?

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Ferram I just wanted to confirm the nosecone problem another member mentioned. Try attaching a KW 1.25m nosecone to a remote guidance unit and let it fall from space. It will begin gliding. It doesnt fall. i was able to glide a nose cone with just a remote guidance unit slowly for miles. it gets up to around 70m/s horizontally and only 10m/s vertically

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I've seen a couple posts in this thread about aerobraking, and how the adjustments to aerodynamics makes the atmosphere much "thinner" for aerobraking, but I haven't really seen if there's a good way to actually calculate aerobrake maneuvers with FAR installed. I've used the online calculator in the past, but that assumes stock aerodynamics, which I'm guessing won't work. Is there a way to accurately calculate aerobraking maneuvers with FAR?

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So I've just put up version 0.9.5.4 which adjusts the lift and drag of blunt bodies. They'll still make less drag, but that's because the drag of a cylinder in cross-flow was far to large in previous versions and it has been dropped down to regular levels. Hopefully, the flying blunt SRB problem is solved.

@Decoherent: Sure! First, find out what the drag and lift coefficients of your vehicle are at the Mach numbers and AoA that you expect to fly through the atmosphere at. Then, find a program that can account for the gravitational and aerodynamic forces acting on the vehicle as it flies through the atmosphere. You'd probably have to build a tool to run all of this. All you need is lift coefficient, drag coefficient, mass of the vehicle, and the planet characteristics.

@NathanKell: Are you sure that the drag on the undeployed parachutes are that high? If setting stowed drag to zero doesn't do anything then I'll have to write my own parachute code rather than leave it alone.

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Yup. My drag losses are ~150 (calculated by Mechjeb's ascent stats, compare expended delta-V to current velocity, gravity, and steering losses (the way mentioned upthread to calculate drag losses).

Then the parachute--with stowedDrag set to 0!--gives me another 50+ m/s losses.

Note that it _does_ do something--it lowers stockdrag losses a lot. Just nowhere near zero.

Try it yourself--launch a simple rocket, even with stowedDrag set to 0, and see what you get.

(And if you get something different, I must have a weird interaction issue?)

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Oh man, drag and lift coefficients change based on speed and angle of attack? (clearly I've never done any of these calculations myself.) I started looking at taking a stab at extending alterB's online calculator with mass, lift, and drag per vehicle, but I didn't realize the coefficients changed. I just started looking through your code (nicely commented, btw), maybe I can come up with a "good enough" approximation to get a ballpark trajectory. Out of laziness, do you happen to have any links to "easy to understand" pages with the required math?

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@ferram: Hmm...so is the problem me and White Owl mentioned fixed, or not? I mean, the plane seems to handle a bit differently, but the L/D line in the graph is still flying off the chart like mad. Is this supposed to look like this now? Thanks, and thank you again for making planes fun to build and fly. :)

EDIT: Also, I just noticed the airbrakes seem to respond to any brake control input within loading distance. As in, two identical planes parked side by side, pressing B on one of them activates the airbrakes on both. It's not gamebreaking or anything, just though you should know.

Edited by Weatherman159
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@ferram: Hmm...so is the problem me and White Owl mentioned fixed, or not? I mean, the plane seems to handle a bit differently, but the L/D line in the graph is still flying off the chart like mad. Is this supposed to look like this now? Thanks, and thank you again for making planes fun to build and fly. :)

Everything he said, I want to say too. The planes handle slightly better than before, but they still seem to have way too little drag. Every plane I try to land is extremely floaty and just won't slow down. The L/D line is still a near vertical line right off the top of the graph.

The problem first appeared for me in 0.9.5.2. I'm still using 0.9.5.1 in KSP .20.2 for now.

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Everything he said, I want to say too. The planes handle slightly better than before, but they still seem to have way too little drag. Every plane I try to land is extremely floaty and just won't slow down. The L/D line is still a near vertical line right off the top of the graph.

The problem first appeared for me in 0.9.5.2. I'm still using 0.9.5.1 in KSP .20.2 for now.

+1 this. I just could not slow down my planes for landing. I began to think about installing few air breaks to assist with landings. Otherwise the planes handle pretty well, but I am having the same problem with the L/D graph.

Edit: I am using the new 0.21.1 KSP and procedural wings + firespitter. Good news is that both of these mods seem to work with the FAR in the new KSP (procedural wing was updated )

Edited by Torham234
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I think I found a bug. Why are the two canards pulling my COL so far forward when they are significantly smaller than the main wing. There are no clipped parts with this.

Without canards:

N1bcpwn.jpg

With canards:

x1bsdpW.jpg

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I've found KSP's spaceplanes exceedingly frustrating  the stock aerodynamic model flies all wrong to this real (albeit low hours) pilot. I just tried FAR  It does make the aircraft 'feel' much more aeroplane-like  and there is warning loss of lift before a stall and nice secondary roll when feeding in too much rudder. But it made everything keep way too much energy  it was almost like there was no drag at all. The stock Aeris was so floaty I could barely land it even power off  it was like trying to bring in a sailplane at the end of a good day, when virtually all the air around is rising slowly. So sadly I uninstalled after an hour or two. :huh:

A neat thing to add would be the ability to define control surfaces as flaperons, so that they droop down and add lift and drag (to allow a slower and draggy-er approach) like flaps but still continue to operate as ailerons â€â€and allow us to leave off separate flaps or airbrakes.

I'll give FAR another go after the next update.

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I wonder if this is partly the infiniglide bug - I've had one or two occasions when FAR wasn't installed correctly that I got control surfaces using default physics, and tweaking FAR's control damping values so it promoted some flutter meant I had self-propelled gliders. I generally use the control surfaces from Taverius' pack, pWings and either of the two default canards, and I've not noticed problems slowing down. A modulemanager dll mismatch might not be loading all the configs, or maybe some people might be using incompatible items?

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Hey there, if you can't see the flight-GUI and your horizontal screen resolution is less than 1348 pixels try this:

Open /ksp-win-0-21-1/GameData/FerramAerospaceResearch/Plugins/PluginData/FerramAerospaceResearch/FAR.cfg in your favorite text editor (eg. notepad) and change the first line to something like this:

SaveWindowPos.x=100

Apparently not all of us look at full HD screens :)

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