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

[AccidentalDisassembly]

There are no variables to tweak, FAR is what it is.

If you're having those problems, it means that your planes are horrendously overweight. Bring their mass down to realistic levels.

All right, I imagined there was some value in a config somewhere for atmosphere density. I see now that FAR quadrupled the mass of the innermost wing parts I attached to my latest craft, reducing that slider helps quite a bit. The added mass of all of the wing parts represented a 50% increase in the weight of the craft compared to the normal mass values (4 tons to 5.8 tons).

EDIT: What you say makes me wonder about the mass of stock parts. Would a 1.25m inline cockpit really weigh 1,030kg? Maybe that's part of my problem as well. Not that it was the same diameter (and definitely not pressurized), but come to think of it I'm not actually sure that my dad's entire sailplane weighed 1000kg.

Edited August 2, 2015 by AccidentalDisassembly

[taniwha]

AccidentalDisassembly: KSP's part masses are insane. It's like their made of centimeter thick iron plate.

[blowfish]

I suspect intended heat shielding has something to do with it, but I doubt that's consistent across all parts.

[AccidentalDisassembly]

Well at least I think I now finally understand why planes aren't behaving like I would expect under FAR! hah. An entire Cessna Skyhawk weighs a bit more than a KSP cockpit: http://cessna.txtav.com/en/single-engine/skyhawk (~1100kg loaded, says the website).

[Ser]

Have you found the solution to this?

According to that NathanKell says, I had to remove RealHeat, unfortunately, and the effect was gone. But now my DRE reentries have become insane.

@ AccidentalDisassembly, I had the same troubles with crafts just not deccelerating on earlier FAR versions but now the drag is much better. Now I'm able to descend from 10000m and decelerate from 250 m/s to 100 m/s in a few minutes. So my advice is if you're on approach, cut your thrust and try to achieve the speed equal to your stalling speed +15% (use spoilers for that) and you'll be comfortable at controlling your velocity on final.

[Wanderfound]

Now I'm able to descend from 10000m and decelerate from 250 m/s to 100 m/s in a few minutes.

Airbrakes and S-turns make it possible to ditch speed and altitude extremely rapidly, BTW.

1) KSC in sight, 27,000m altitude, speed Mach 4.5:

2) One minute later, subsonic in a vertical dive:

3) Touchdown, 75m/s, 3 minutes after the first pic:

The airbrakes make it a lot easier, but they aren't necessary. So long as you build in a decent amount of g-tolerance and not too much wing loading, you can get similar levels of deceleration from S-turns. Just keep alternating 5-10g banking turns until you've got the speed down to where you need it.

The real limit is heat; super-rapid descents without airbrakes have a tendency to melt your wings off, especially if they're still warm from the ascent.

Edited August 2, 2015 by Wanderfound

[cantab]

All right, I imagined there was some value in a config somewhere for atmosphere density. I see now that FAR quadrupled the mass of the innermost wing parts I attached to my latest craft, reducing that slider helps quite a bit. The added mass of all of the wing parts represented a 50% increase in the weight of the craft compared to the normal mass values (4 tons to 5.8 tons).

Yeah. FAR defaults to a "Wing Strength" which is typically higher than needed. FAR also changes the mass of a wing panel depending on what other parts are attached to it, and in some situations that can result in truly enormous masses for a single wing piece.

As a very crude rule of thumb:

0.25: very light, very fragile. Eggshell glider, handle with care, especially at low altitude. Roughly equivalent to how all wings were before the mass tweakable was introduced.

0.5: Thoroughly solid, good enough for anything but extreme aerobatics or wing loading. Can be shaved down a bit further for a sensible pilot.

0.8: Extra tough, good for flight trainers, superheavy Mk3 stuff, light aerobatics.

1.0: Fighter strength, unnecessary unless you're intending to pull extreme high-G low altitude aerobatics.

>1: Magic plane with Adamantium wings. You'll probably snap the fuselage in half before the wings break. Good for having a giggle in tight mountain passes.

(note: this is based on oldFAR, I haven't messed with the dev build yet)

[T-Pilot395]

Hi all,

Just wondering, if there is a specific way to fly VTOL craft when using FAR? Because my most recent design, while it can hover pretty well (CoT under CoM), once I start ascending past a certain speed, any input to the pitch control causes the plane to attempt to snap to the prograde marker, throwing it into some flips, and back into the ground.

Is there a certain 'ascent speed' I should limit myself to? Because as far as I know, the design functions pretty standard for a VTOL, until it ascends past a certain speed.

[Wanderfound]

Hi all,

Just wondering, if there is a specific way to fly VTOL craft when using FAR? Because my most recent design, while it can hover pretty well (CoT under CoM), once I start ascending past a certain speed, any input to the pitch control causes the plane to attempt to snap to the prograde marker, throwing it into some flips, and back into the ground.

Is there a certain 'ascent speed' I should limit myself to? Because as far as I know, the design functions pretty standard for a VTOL, until it ascends past a certain speed.

Think about the physics involved; once your ascent speed starts to wind up, you're essentially flying a plane at a 90° AoA. Unless the craft is built to cope with that, regrettable things will happen.

You can reduce the effect by minimising your wing surface (if it can VTOL you don't need much aero lift anyway) and keeping the lifting surfaces relatively balanced around CoM.

VTOL piloting demo (one of my ships, but not my piloting):

(note: this is from before they nerfed basic jets; you'd need a turbojet for the lifting engine these days)

Edited August 2, 2015 by Wanderfound

[Ser]

ferram4, what the setting "Aero failures create explosions" does? Won't aerofailures affect vessel integrity if I disable that or that will still happen just not in the form of explosion?

[taniwha]

Ser: turning that off causes the broken parts to flutter off rather than explode. Has no effect at all on actual aero-failure.

[T-Pilot395]

Think about the physics involved; once your ascent speed starts to wind up, you're essentially flying a plane at a 90° AoA. Unless the craft is built to cope with that, regrettable things will happen.

You can reduce the effect by minimising your wing surface (if it can VTOL you don't need much aero lift anyway) and keeping the lifting surfaces relatively balanced around CoM.

(note: this is from before they nerfed basic jets; you'd need a turbojet for the lifting engine these days)

As a aeronautics student I have no idea why I didn't come to that conclusion earlier. Thanks for the advice! I'll work on the design again.

[cantab]

If you want a VTOL that can climb or descend fast in VTOL mode I can think of three approaches. A tiltwing might work by avoiding the issue of having the main wing at 90° to the airstream. A tailsitter can certainly work and climb fast but transitioning from forward flight back to a hover can be tricky and they typically have to descend slowly since descending is basically flying backwards. Or of course you could build a helicopter.

[Manwith Noname]

Ferram, I wonder if at all possible you could take some time to look at this thread and offer some insight as to what might be going on.

Primarily, I am curious if FAR changes the behaviour of the stock aerodynamics overlay, as in, does it include a replacement overlay to some extent? If not, how does the overlay interface with the aerodynamics models because the problem seems to go away with FAR installed. I only ask because you are without doubt, the most qualified person I know of to be able to answer these questions or simply see what is going on based on your work. It may take you 2 minutes while for the player, we will just be stumbling around scratching our heads.

[NdranC]

Is this mod FPS heavy? Normally with my full mod installation I have 50+ FPS during launch but with FAR I get 35ish with severe stutter in the same install. Any clues?

[NathanKell]

According to that NathanKell says, I had to remove RealHeat, unfortunately, and the effect was gone. But now my DRE reentries have become insane.

Or just turn that bit off in RealHeat:

@REALHEAT
{
	%aeroFXdensityMult1 = 0
}

stick that in a cfg in gamedata.

Or adjust AeroFX the way RO does, the default RealHeat settings are designed to work with RO's changes to AeroFX (no flames at 20km (Earth alt) and 900m/s, slight flames at 1050 at that alt, not much of anything above 25km unless you're at Mach 10+)

[cantab]

Is this mod FPS heavy? Normally with my full mod installation I have 50+ FPS during launch but with FAR I get 35ish with severe stutter in the same install. Any clues?

I've been doing extensive fps testing lately and I found no measurable difference between stock and FAR. Mind you my test is with a 600-part lagfest rocket to really focus in on the CPU performance. It's also possible FAR is interacting badly with another mod. Look in particular at anything with animated or moving parts, they might end up constantly causing FAR to recalculate the shape of the vessel.

[blowfish]

Is this mod FPS heavy? Normally with my full mod installation I have 50+ FPS during launch but with FAR I get 35ish with severe stutter in the same install. Any clues?

It's possible that one of your mods has an animation that is updating constantly. A constantly updating animation will cause FAR to re-voxelize the vessel every half second, though this is usually done on a different thread.

[NdranC]

It's possible that one of your mods has an animation that is updating constantly. A constantly updating animation will cause FAR to re-voxelize the vessel every half second, though this is usually done on a different thread.

I do have some mods related to animations. I have Collision FX, CoolRockets, Engine Lightning, Real Plume, Ven's Stock Part Revamp. It's all I can think of. Any of these mods are know to cause problems with FAR? The problem is not even low FPS its just the constant stutter that gets in the way of my inputs.

[TheGamingNoobster]

Just curious, this may have already been brought up but... Are the update names (e.g. Goldstein, Fanno, Euler) all named after scientists who worked on or figured out more about aerodynamics? The names I can recognise are.

Thank you

[Bakase]

I do have some mods related to animations. I have Collision FX, CoolRockets, Engine Lightning, Real Plume, Ven's Stock Part Revamp. It's all I can think of. Any of these mods are know to cause problems with FAR? The problem is not even low FPS its just the constant stutter that gets in the way of my inputs.

I don't think any of these should be causing issues. It's more likely to be a moving or animated part -- particles and effects shouldn't have anything to do with FAR! Could you give us a screenshot or a craft file of something that causes the problems?

[damerell]

These graphs are all blank, and the values are all zero. I started with a fresh install of 1.0.4. No matter how many aerodynamic surfaces I add to the bottom of my rocket it is unstable. No amount of RCS, control surfaces, reaction wheels, and gimbals can hold this rocket upright.

It would be interesting to see a picture of the rocket (albeit perhaps not in this thread) and also to know if the same rocket flies in stock.

The usual reason rockets flip is not bad design (well, often it is hem-hem) but because they are pointed away from surface prograde. Fundamentally a rocket is not suited to a high angle of attack.

[sashan]

Ok, I understand you have no info about my bug. But how do you save full log when the game doesn't crash? When it does it saves it itself, I know.

SO far I've rolled back to previous version, works fine. This is no installation error, I've checked it.

[Wanderfound]

Ok, I understand you have no info about my bug. But how do you save full log when the game doesn't crash? When it does it saves it itself, I know.

SO far I've rolled back to previous version, works fine. This is no installation error, I've checked it.

Sashan: see http://forum.kerbalspaceprogram.com/threads/92229-How-To-Get-Support-%28READ-FIRST%29

Strip the game back to the bare minimum amount of mods that will cause the bug, find a set of steps that will reliably cause the bug to occur, go through those steps, then exit the game and find the log files as described in the link above. Also report exactly what mods are involved and exactly what the bug reproduction steps were.

[NdranC]

I don't think any of these should be causing issues. It's more likely to be a moving or animated part -- particles and effects shouldn't have anything to do with FAR! Could you give us a screenshot or a craft file of something that causes the problems?

This is the craft, it happens with anything I launch so far. I've also noticed in the launch pad I have a slight stutter every 8 seconds almost on the dot dropping me from 60 to 47 fps and when I launch, the stutter happens every 2 seconds constantly with very noticeable skips, even the audio skips. I tried the exact same setup without FAR and Advanced Jet Engine and the stutter is pretty much gone.

In case it helps this is my mod list Page1, Page2 and Page3.