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

[theend3r]

How do I remove aerodynamic failures from a single part? I use airbags from USI Survivability Pack but they get torn off every time during reentry.

[Northstar1989]

No, it's just that if you have one wing right on top of another, the drag is increased and the lift is not, as taniwha said. Doesn't matter what you want to use them for, that's what happens and it's not a bug, it's real aerodynamics.

You're not listening to what he said. He reported that when adding a second wing on top of the first, the lift icon moved BACK, towards the rear of the plane- which shouldn't happen. Adding a second wing that close to the first doesn't meaningfully increase lift (adding two wings with a significant gap DOES increase lift- by at least 10-20%, however), but it shouldn't CANCEL the lift of the first wing. That's a serious bug with the wing interaction code if the lift icon is accurate.

Regards,

Northstar

[Northstar1989]

@Ferram

There's definitely something wrong with the 0.14.3 lift code (possibly one of the things you fixed by 0.14.3.2? I'm not running the latest version yet). I keep coming up with results like THIS:

This plane checks out as all green on the stability screen at the relevant air pressures and speeds, yet INSISTS on rolling partway over like this. This is what it flies stably at too- it's not rolling back and forth... (you can ignore the MechJeb setting, by the way- I only set it to -12 degrees roll because it was flying stably at that anyways, and didn't want it to suddenly freak out if that somehow changed...)

It's got strakes on the underside, and the wings are multi-part, so it's quite possible it's been fixed with changes in the wing interaction code in 0.14.3. I haven't been able to check yet...

Regards,

Northstar

Edited October 28, 2014 by Northstar1989

[Voculus]

You're not listening to what he said. He reported that when adding a second wing on top of the first, the lift icon moved BACK, towards the rear of the plane- which shouldn't happen. Adding a second wing that close to the first doesn't meaningfully increase lift (adding two wings with a significant gap DOES increase lift- by at least 10-20%, however), but it shouldn't CANCEL the lift of the first wing. That's a serious bug with the wing interaction code if the lift icon is accurate.

Regards,

Northstar

I think the CoL moving back makes perfect sense. By sandwiching two wings, their ability to generate lift is spoiled, and the indicator moves back towards the main wings as a result.

[NathanKell]

Please update to the latest FAR. If the issue is still there, *then* report it.

[ferram4]

@theend3r: You don't. You either fly a better trajectory, protect the part with fairings, or turn off aerodynamic failures entirely. You don't get to play god.

@Northstar1989: You mean the issues that the patches were released to fix?

[theend3r]

@theend3r: You don't. You either fly a better trajectory, protect the part with fairings, or turn off aerodynamic failures entirely. You don't get to play god.

@Northstar1989: You mean the issues that the patches were released to fix?

The trajectory is as shallow as possible. Fairings? If there are any closed SP-L solar panel size fairings would you be so kind as to redirect me to them? Otherwise the parts have their own "fairings" as they are deployed out of a protective box.

I hoped it can be done by creating a .cfg for the part, maybe make the drag 0?

[Wanderfound]

The trajectory is as shallow as possible. Fairings? If there are any closed SP-L solar panel size fairings would you be so kind as to redirect me to them? Otherwise the parts have their own "fairings" as they are deployed out of a protective box.

I hoped it can be done by creating a .cfg for the part, maybe make the drag 0?

http://i.imgur.com/cCYCA4G.jpg

You've stuck a lightweight box on the outside of the heat shielding, directly in the path of the hottest zone of reentry effects, and also at the most intense point of aerodynamic stress. It should die if you put it there. Shift it further back and it'll be fine.

Note the solar panel placement on this:

Comes through a hot reentry and max-Q flight without any fuss. It may take a bit of creativity to balance reentry survivability with useful airbag placement, though.

Why do you want airbags on a winged aircraft, anyway?

[theend3r]

You've stuck a lightweight box on the outside of the heat shielding, directly in the path of the hottest zone of reentry effects, and also at the most intense point of aerodynamic stress. It should die if you put it there. Shift it further back and it'll be fine.

Note the solar panel placement on this:

http://i1378.photobucket.com/albums/ah120/craigmotbey/Kerbal/IVA%20landing/screenshot392_zpseffbb3b8.png

Comes through a hot reentry and max-Q flight without any fuss. It may take a bit of creativity to balance reentry survivability with useful airbag placement, though.

I know that. I also have two in the rear near the engines and they actually get torn off even sooner. I RP that they are intgrated into the parts.

Why do you want airbags on a winged aircraft, anyway?

Emergency landing using only parachutes. The CoM shifts a lot.

Edited October 28, 2014 by theend3r

[nli2work]

Hey Ferram can you clarify the variables in BasicDragModel a little when you get a chance? Or if there's a place with a succinct description on the forums or else where. I found one post from 2012, #53. Is that still applicable? seems like quite a lot has changed looking at the newer BasicDragModel settings.

[Wanderfound]

I know that. I also have two in the rear near the engines and they actually get torn off even sooner. I RP that they are intgrated into the parts.

Emergency landing using only parachutes. The CoM shifts a lot.

Just a thought, that may be wildly impractical or not depending upon how the airbag mod works, but...have you tried sticking them in a cargo bay? Pretty much all of my ships have a least a small service bay, just so I have somewhere to stash fragile and unaerodynamic things (SAS, batteries, science gear, spotlights, etc) out of the airstream.

The other issue may be rotation. Things placed with rotation as well as radial attachment (e.g. sticking Vernors on the flanks and rotating them 90° to use as retrothrusters) have a tendency to be highly vulnerable to FAR: it seems to see them as things that are stuck out into the wind. Are the rear airbag boxes that are tearing off mounted perfectly flush to the surface they're attached to?

[theend3r]

Just a thought, that may be wildly impractical or not depending upon how the airbag mod works, but...have you tried sticking them in a cargo bay? Pretty much all of my ships have a least a small service bay, just so I have somewhere to stash fragile and unaerodynamic things (SAS, batteries, science gear, spotlights, etc) out of the airstream.

The other issue may be rotation. Things placed with rotation as well as radial attachment (e.g. sticking Vernors on the flanks and rotating them 90° to use as retrothrusters) have a tendency to be highly vulnerable to FAR: it seems to see them as things that are stuck out into the wind. Are the rear airbag boxes that are tearing off mounted perfectly flush to the surface they're attached to?

No they are strongly tilted, that may be the problem. That still doesn't answer my question though. I'll try to play with the .cfgs a bit and see what I can do. Thanks for the replies.

[Northstar1989]

@Northstar1989: You mean the issues that the patches were released to fix?

You're right. I updated FAR, and the problems *appear* to have went away... (further testing will be necessary to validate this) I guess I should have updated *before* posting that.

Regards,

Northstar

Edited October 28, 2014 by Northstar1989

[ferram4]

@nli2work: Try the readme file.

[mech_engr]

How would a modder go about setting up a wing with animated flaps, slats, or spoilers to work with FAR? I'm trying to work out a concept for a new mod that incorporates the flight performance of FAR but has visually appealing and animated, dedicated flaps, slats, and spoilers that affect lift and drag separately. Anybody have any ideas on how to do this?

[Wanderfound]

How would a modder go about setting up a wing with animated flaps, slats, or spoilers to work with FAR? I'm trying to work out a concept for a new mod that incorporates the flight performance of FAR but has visually appealing and animated, dedicated flaps, slats, and spoilers that affect lift and drag separately. Anybody have any ideas on how to do this?

Nope, no idea.

However, for the flaps and spoilers, FAR already does that. Use the right-click tweakables to disable the control surface in all normal axes and then set it as a flap or spoiler.

[RadarManFromTheMoon]

Would be nice if the FAR GUI would also appear while flying a craft without a pod, but with a Kerbal in a command seat.

[Superfluous J]

This is one of the tiniest bugs I've ever reported. When I leave the atmosphere, the FAR button vanishes off the (stock) toolbar. This isn't a huge deal because hey, what do I need that button for I'm in space. However, if the FAR gui window is open at the time it stays open and there is no way (that I know of) to get it to go away now that the button is gone.

If I leave the space scene (and go back to to the space center or exit the game and reload) the button is back and I can remove the window.

[ferram4]

@mech_engr: For all of those surfaces in a single part? FAR doesn't support that. You'd also get much more accurate behavior by having each surface be distinct from the wing itself.

@RadarManFromTheMoon: Not gonna happen.

@5thHorseman: That shouldn't be happening, the button is only ever removed when leaving the flight scene. Post logs and full reproduction steps.

[FreeThinker]

I seem to have a problem with FAR. The breaking function of control surfices of my planes do not seem to have any effect, making landing very hard. Also, I noticed that when I try to enable the flaps and spoiler of a control surfice, in the editor, the frame rate drops down considerably. Are there any fixes for these problems?

Edited October 29, 2014 by FreeThinker

[Wanderfound]

Spoilers are for descent and downforce, not braking. They increase drag, but the slowing effect is slight. Use S-turns, loops and retro-thrust RCS or Vernors to slow in the air.

[FreeThinker]

Spoilers are for descent and downforce, not braking. They increase drag, but the slowing effect is slight. Use S-turns, loops and retro-thrust RCS or Vernors to slow in the air.

Are there any other ways to slow down. Even if I turn all the engines off, it seems to take a very long time before I slow enough to land safely.

Edited October 29, 2014 by FreeThinker

[Wanderfound]

Are there any other ways to slow down. Even if I turn of the engines, is seems to take a very long time before I slow enough to land safely.

As I said: S-turns. Aircraft are essentially doing a controlled fall through the air; they don't naturally come to a stop on their own. You need to disperse the energy of the aircraft, either by using it in a series of banking turns in alternating directions, flying a complete horizontal or vertical loop, or doing a series of climb/dive manoeuvres.

See the second post of the Kerbodyne thread linked in my sig below for a piloting guide.

[Voculus]

Are there any other ways to slow down. Even if I turn all the engines off, it seems to take a very long time before I slow enough to land safely.

The B9 and Firespitter mods both come with speed brakes. They're hugely helpful, and they get added to any and every plane I make.

[theend3r]

The B9 and Firespitter mods both come with speed brakes. They're hugely helpful, and they get added to any and every plane I make.

This plus RealSchutes for runway breaking. Some of my cargo planes touchdown at nearly 200 m/s.