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

[Tripod27]

@ferram:I'm sorry. I feel bad for making all these requests...

But one thing that as always irked me is the high connection strength that all parts in KSP have. It takes one of the limiting factors of aircraft design (maximum g-force) and blows it wide open. If I build a craft correctly, I can reach 20 g using only stock, more if I use pWings (because of how it overestimates connection force to allow for Error.) But in order to decrease the breaking strength, you also decrease the connection stiffness, right? (Exacerbating spaghetti craft and the "always rolls left" bugs.)

Is there a workaround for this? Can we go plead with Harvester to increase the stiffness of part-part connections? I just miss the days when my aircraft would spontaneously disassemble if I took a hard turn above Mach 1...

*note: I rarely, if ever, use struts.

try the deadly re-entry mod

It makes high G's affect you more (to stop people diving straight at the planet at 20 G's to avoid overheating for too long) and whenever I use it most of my planes rip themselves apart if they stay in an 8+ G turn for more than a few seconds (warning: makes cockpit flight nearly impossible due to the lack of G meter besides the high G light that turns on at like 15 G's)

[Hodo]

try the deadly re-entry mod

It makes high G's affect you more (to stop people diving straight at the planet at 20 G's to avoid overheating for too long) and whenever I use it most of my planes rip themselves apart if they stay in an 8+ G turn for more than a few seconds (warning: makes cockpit flight nearly impossible due to the lack of G meter besides the high G light that turns on at like 15 G's)

So true, DRE is another MUST have in my mod list.

[ferram4]

@AtilaElari: What exactly are you trying to bring down? A command pod alone? That wouldn't be FAR breaking that. A complex lander? Not much you can do besides using more struts and taking a more shallow angle. I'm still concerned that if your rocket has parts being destroyed "due to overheating" as you mentioned in your earlier post that you haven't fully uninstalled Deadly Reentry and that that is the cause of most of your problems.

@uselessengineer: Unfortunately, no. You do have the option of going through the debug log and adding up all of the areas printed out when FAR's modules are initialized. I did just make a change to the current build to support that, so when there are enough changes to justify another release of the old version of FAR, I'll put that out.

[5parrowhawk]

Thanks for the suggestions, folks. I only added the flaps because I thought the problem was due to insufficient lift on the main wing; will try moving the canards forward and see. I guess I could also give those rear elevons another shot... Any idea whether leading-edge slats on the main wing would help or hurt?

For that matter, the old British Vulcan bombers had a similar topology; how did they deal with that? Wing cross-section designed to provide more lift at the root and leading edge, or some such? (I note that their first low-speed prototype actually crashed...)

[Senshi]

Had a weird experience with FAR just now. After a suboptimal reentry of my SSTO (it flipped, facing retrograde in upper atmo) I wondered why it didn't simply break apart (I use DRE) in the "hot" zone of ~30km and instead slowed down incredibly fast as well.

When reaching 20km, my speed was down to 200m/s . That's when I got really worried and checked the flight data of FAR. I apparently have deployed an invisible town-sized airbrake that increased drag to a bit of a ridiculous value.

After "stalling" down the rest of the way, I managed to land with 5m/s horizontal speed by giving full thrust on both the B9 SABREs.

Then, after going to the tracking station and back, everything was back to normal again.

Just thought I'd report this, even if it was not gamebreaking and probably a one-time bug.

EDIT: Just noticed I know the cause and can reproduce it: I quicksaved before my reentry at ~60km. Everytime I quickload, my SSTO gets a drag value of ~34 at 60km already. I guess FAR doesn't like in-atmosphere loading?

Oh, and just to say the obvious again: I cannot thank you enough for your continuous work on this mod. I recently played stock to create some tutorials and KSP is just dull and "simple" without this mod. You managed to hit a perfect balance between logical realism and easy gameplay. While you offer lots of super detailed info for professionals (like the simulations and derivatives that no layman understands), the mod is perfectly open and fair to casual players as well: If a plane/SSTO/rocket resembles a real counterpart in shape, it will most probably fly. And it even flies much better than in stock KSP (reward for good design!). Else you'll crash and burn (and learn). It's hard to say how much I learned about aerodynamics without even trying, which keeps perfectly in line with how much I learned about astronomy and rocket science by playing KSP in general.

Edited October 6, 2013 by Senshi

[ferram4]

@Senshi: Could you post a copy of the output_log.txt? It might be something going wrong during the initial setup of the drag model. What mod parts are on that craft?

[TomatoSoup]

Is there any way I can toggle this mod on and off while ingame? I love it for planes, but it really throws me off for aerobraking, especially because it seems to break Mechjeb's aerobraking prediction. Unless that's been fixed with a recent version, I haven't checked in a while.

[taniwha]

TomatoSoup: there is no way to toggle FAR (as it should be!). The cost of "easier to orbit" is "more difficult to land". TANSTAAFL. Besides, stock aerodynamics doesn't let an FL-T800(or 2?)+LV-T45+command pod generate lift (applications of that are left to the imagination).

[TomatoSoup]

TomatoSoup: there is no way to toggle FAR (as it should be!). The cost of "easier to orbit" is "more difficult to land". TANSTAAFL. Besides, stock aerodynamics doesn't let an FL-T800(or 2?)+LV-T45+command pod generate lift (applications of that are left to the imagination).

I'm not asking for it to be any easier to land. I just want to be able to aerobrake with the old drag model. That's the exact thing: I don't want those to generate lift.

[ferram4]

@TomatoSoup: Honestly, the only way that I would add that feature is if I were able to add it to the cheat menu, as I consider it to be similar to the "hack gravity" switch in there. FAR is primarily based around trying to make the game as realistic as possible, and allowing the player to simply flip the drag model on and off (or the type of drag model) that easily defeats the purpose.

I'd say that the best way to go about aerobraking is to quicksave and just try something. Have the ship spin a bit as it goes into the atmosphere to help make it more stable and see what happens. Don't like the result? Call it a "simulation" run and quickload, try again.

[Camacha]

I'm not asking for it to be any easier to land. I just want to be able to aerobrake with the old drag model. That's the exact thing: I don't want those to generate lift.

I do not see the point, besides manipulating the circumstances to what is easier for you. You can do it by installing a mod manager and toggling FAR. I do not see much use for anyone else.

[Bobhendly]

Would SSTOs Be impossible with FAR Combined with DRE?

Would I burn up in atmo trying to accelerate to orbital velocity?

[NathanKell]

I'd hazard a guess that most of the people who post in this thread use DRE (as do I). So you're fine.

You'll note (in DRE's cfg file) that spaceplane nosecones and fuselages function as heatshields, among other things.

[TomatoSoup]

I'd say that the best way to go about aerobraking is to quicksave and just try something. Have the ship spin a bit as it goes into the atmosphere to help make it more stable and see what happens. Don't like the result? Call it a "simulation" run and quickload, try again.

Fair enough, I suppose. That's just so much less elegant, you know? Especially for aerocaptures where the periapsis burn is done months in advance.

As I understand it, MechJeb loses the ability to predict aerobraking because you set all the default drag values to (pretty much) zero. Is there any way you can have an option to briefly restore those when not in atmosphere? Imagine that I intend to blast through the atmosphere while pointing prograde the entire time. I hit this button while pointing prograde in space and it tells me what my drag will be so long as I'm prograde. Then when I enter the atmosphere, it goes back to regular FAR aerodynamics and the accuracy of the prediction depends on my ability to hold the rocket prograde.

Because, honestly, even more than making FAR toggleable, I'd rather it have compatibility.

[Bobhendly]

What about procedural wings?

[NathanKell]

Look at the very post from which you downloaded it. It says "Reflective FAR support: Reflective FAR support means that to install the FAR version you simply make sure that FAR is installed."

[Delta Force]

I'm using FAR, TPA, and B9 and am having issues getting my turbojet engines to feed from wingtip mounted Jet A fuel tanks. Fuel lines don't help, any suggestions on how to get it to work?

[Senshi]

@Delta: Give us pictures. Fuel lines always work, it's highly likely that you attached them not to the right parts (they like to do that on their own, gotta be very careful during placement).

@ferram:

I already had moved on with my save, so I recreated the situation. Quicksaving in atmosphere is only possible if your orbit does not intersect ground yet, so I went for a harmless 60km periapsis. I saved right at ~66km this time, and after quickloading drag value instantly was at ~27.

http://i.imgur.com/wvyVR0K.jpg

Here's the related part from the output_log.txt: http://pastebin.com/bh4fXx04

I clipped it to start right from the quickload and also added some debug clutter the KAS mod caused.

You'll see a number of mod plugins being loaded right there.

In terms of mod parts on the craft: It's B9 plus pWings and MechJeb. The rear wheels are from Touhous Multiwheels mod. Rest is Squad.

Edited October 8, 2013 by Senshi

[Pyromaniacal]

Here's an oddity I found. I built a probe to skim through and ultimately get blown up by Jool. I had the 1m nosecone on the front, and had a 1x1m plate on the back to provide drag towards the rear, like so.

This was done so that the "heatshield" would enter first.

Once the probe entered atmosphere, it behaved exactly the opposite way, lining up with the plate entering first, like so.

Sorry, the reentry flare is in the way.

I tried flipping the probe around, and deploying the parachutes, but this didn't help. Aside from FAR and Procedural Fairings, the craft is stock.

Am I correct in assuming that this should not be the case, and the nosecone should have less drag than the plate would?

Edited October 8, 2013 by Pyromaniacal
Tenses got mixed up.

[ferram4]

@TomatoSoup: I believe that MechJeb constantly updates the aerobraking prediction, so FAR would have to apply the proper drag values to the fuselage parts and then remove it at the very last second as the atmosphere starts, though that would result in the aerobraking prediction going to hell the second you got into the atmosphere. And even then, the aerobraking prediction would only hold if you had no lift on the vehicle. It would just be easier for me to code my own calculator for it.

@Delta: You're making sure that the fuel line runs from the wingtip fuel tank directly to a fuel tank stack that does feed the engine, correct? You might get away with a fuel line connecting the fuel tank to the wing and then the wing to the main fuel tank stack, but I think your issue is that you're expecting fuel to drain in the reverse of the way it is coded in KSP.

@Senshi: It's B9 doing something weird... For some reason the area values for the inlets is not only wrong but different for each inlet, which makes this a particularly bad bug. I will look into that.

@Pyromaniacal: The plate was much heavier than the nosecone was, shifting the CoM backwards more than it shifted the CoL. It also looks like there's an RTG in there that is connected to the plate, which would shift the CoM further back as well.

Edited October 8, 2013 by ferram4

[Taverius]

@ferram4: Finally have a computer that can run 0.21 without bluescreening, wondering if FAR auto-calculates e yet?

[ferram4]

@Taverius: Nope, FAR doesn't auto-calculate e, and the current part-centric version probably never will. The more assembly-based version I'm working on will have to though, but that's a bit in the future.

[Tiron]

@Senshi: It's B9 doing something weird... For some reason the area values for the inlets is not only wrong but different for each inlet, which makes this a particularly bad bug. I will look into that.

It's not the only thing weird with the B9 inlets. The Diverterless Supersonic Intake (the smallish radial one) has a habit of causing me to have flameouts. FAR reports having more than 100% of intakeair requirement. On one of my planes, it would flame out pretty reliably at around 107% of intakeair requirement. It's also throwing Mechjeb off, because the 'Prevent Flameouts' isn't catching it at all, either.

On one of my planes I fixed it by swapping out the DSIs for new instances of the same intake, like it was something intermittent that was tied to that particular instance of them. Now It's recurring on one of my other planes, even after swapping the DSIs out multiple times.

I Know it's the DSIs causing it, because if I close them, mechjeb throttles down and the engine relights, with FAR showing just barely over 100% of airflow requirement.

I suspect it's related to what you noted, but it suggests something more deeply weird could be going on with those intakes.

[Taverius]

@tiron: The DSI Intake is a 100% stock intake with perfectly normal values ... nothing weird there, check yourself. Not sure what could be wrong with it, though I'll check.

@ferram4:You can't mention something like 'assembly-based version' and not give out any details

[Camacha]

@tiron:@ferram4:You can't mention something like 'assembly-based version' and not give out any details

I am with stupid