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

[jrandom]

Be careful though, since RCS Build Aid isn't updated for .23 and tries to call a missing EditorLogic method (works for a while, spewing to log, but eventually dies).

I've heard that but I haven't had it crash on me yet. dCoM is just too useful to give up! I've been keeping an eye on KSP's memory usage and it doesn't appear to be inflating out of control (yet).

[ferram4]

@Camacha: It's probably the uneven joint flexing issue. Best way to solve it is to find the problem part and strut it down. Also, welcome to engineering; moderation is key and slight changes can make huge differences in flight characteristics.

@SFJackBauer: There's a 2 second cooldown on the deflection action groups; I'm going to reduce it, but try not to rush through all of the flaps. They default to setting 2 since that's about the setting that most planes take off in. The deflection levels correspond to:

0 - Cruise

1 - Climb

2 - Takeoff, initial climb, descent

3 - Final descent, landing

[SnappingTurtle]

Quick question: Do the solar panels with casings cause less drag in FAR than those without casings?

[Donziboy2]

Sigh, I have tried moving the mass forward and even behind CoL and it always does a backflip on takeoff.... Any ideas?

[longhornchris]

I thought Procedural Wings 0.6 had questionable FAR support and was waiting for the next update.

[FenrirWolf]

I'm no expert, but my first thought is that the overly large wing surface gives it too much drag for its own good. I don't know if the engines can push it forward fast enough to get proper lift.

[Fred9001]

Is it just me or does the flight Controls like LVL AoA etc not work? They seem to have no effect at all

[DaMichel]

@Donziboy2: A couple of people here including me noticed the backflip tendencies. I believe the stability analysis & CoM/CoL display have definitely become less accurate since 0.23. Using/not using PWings didn't change a thing for me. My solution is simply to put the CoM more forward than i would have done in 0.22 and add plenty of control authority to overcome mach tuck.

Edited December 22, 2013 by DaMichel

[Donziboy2]

@Donziboy2: A couple of people here including me noticed the backflip tendencies. I believe the stability analysis & CoM/CoL display have definitely become less accurate since 0.23. Using/not using PWings didn't change a thing for me. My solution is simply to put the CoM more forward than i would have done in 0.22 and add plenty of control authority to overcome mach tuck.

Ya i just tried that and ended up moving the CoM beyond the cargo bay...... And that made it stable enough to take off, but it was still to twitchy to fly.

[illectro]

I realise that this was with older versions of FAR - but I tried flying lifting body aircraft

[ferram4]

@SnappingTurtle: Not to my knowledge. Ideally the ones without casings would be broken on ascent if they weren't in fairings, but I can't really change that.

@Donziboy2: Yeah, there's a bug that makes the Static Analysis tab less accurate this version. You can probably fix that plane by using smaller wings much further back; what happens to the CoL if you try tilting the plane up?

@Fred9001: Are you leaving SAS on? SAS overrides everything.

@illectro: Yay! More videos!

[FlowerChild]

Ferram, any idea why a design like this might not fly straight up without any control input? It seems to have a tendency to veer over as pictured which I haven't encountered with other designs. Note that while I added fins (those are static ones in 4 way symmetry, they aren't control surfaces) on that last test, it seems to behave pretty much the same without them.

I'm a little puzzled as to what is causing it, or how to correct it, and was hoping you might be able to spot something I missed

Edited December 22, 2013 by FlowerChild

[ferram4]

It probably doesn't start going straight up, and that leads to the effect of a very early gravity turn.

[FlowerChild]

It probably doesn't start going straight up, and that leads to the effect of a very early gravity turn.

Hmmm, it's possible, but I've been locking it down with launch stabilizers, and while other designs tend to diverge slightly from vertical, it's *really* pronounced with this one with as you can see above, it hitting close to a 45 degree pitch only 1500m off the launch pad.

It flies very similar actually to when I've tested launching blunt nosed designs and they're unstable as a result.

As an aside and just to verify: static fins should act to stabilize flight with FAR installed, correct?

[ferram4]

They will. Which means that any slight deviation from vertical will be more noticeable, since instead of the rocket continuing to try to fly almost-straight-up-but-not-quite it will aim down the velocity vector, which is going further off of straight up every second.

Fins make the rocket more stable with respect to the velocity vector. If the velocity vector is off of vertical, it'll bring the rocket off of vertical.

[Andon]

OK, so I'm still having the constant low-grade pitch down and can't seem to get rid of it. Made me think - On pretty much every modern aircraft, they can adjust the settings of some control surfaces to counteract these sorts of things. Is that a planned thing for FAR?

[ferram4]

You mean trim? ALT + WASDQE? Been in the game stock for many versions now?

[jrandom]

OK, so I'm still having the constant low-grade pitch down and can't seem to get rid of it. Made me think - On pretty much every modern aircraft, they can adjust the settings of some control surfaces to counteract these sorts of things. Is that a planned thing for FAR?

You mean sort of like a way to set trim within the SPH?... that'd be pretty slick, actually.

[FlowerChild]

They will. Which means that any slight deviation from vertical will be more noticeable, since instead of the rocket continuing to try to fly almost-straight-up-but-not-quite it will aim down the velocity vector, which is going further off of straight up every second.

Fins make the rocket more stable with respect to the velocity vector. If the velocity vector is off of vertical, it'll bring the rocket off of vertical.

Cool, yeah, I realize that bit about fins adding stability relative to the current velocity, and the attitude of the rocket being perfectly centered on the velocity vector in the above screen supports that's what is happening here, so I guess I'll just chalk it up to launch pad instability.

Thanks for taking the time to respond Ferram. Much obliged.

[Donziboy2]

@Donziboy2: Yeah, there's a bug that makes the Static Analysis tab less accurate this version. You can probably fix that plane by using smaller wings much further back; what happens to the CoL if you try tilting the plane up?

Nothing odd happens when I tilt it, I tried moving the wings back/forward/shrinking, each time I either loose it at liftoff or I get to 8Km and the damn thing refuses to go up....

Its also got a twitch to it, I have been flying with a joystick and I will have it going straight for a short while then all of a sudden it would pitch up and sooner or later I would not be able to stop it and stall out. It does the same thing to MJ and to stock SAS(which is a worthless drunk atm).

Edit....

After playing some more and adding struts to my noodle of a plane(and I have Joint Reinforcement installed...) I got enough twitch out to get it off the runway and up to 10Km. The problem I run into is that whenever I get near Mach 1 my plane noses up... Even above 12Km I loose control.

I did my best to match the wings up to my B9 winged version. The B9 Version is air hogged since it can almost reach orbit atm, still needs some tweaking, biggest problem is its almost 400 parts...

The PW version has about 180m^2 less wing but its also 20T lighter. And under 200 parts so its not to laggy. Its not hogged but it hasnt gotten high enough to need it yet.

If anyone wants to play with them they only need FAR, B9, KSP Interstellar, Mechjeb and PW.

Edited December 23, 2013 by Donziboy2

[localSol]

I can try it donziboy, have you posted the craft file somewhere? I have flown very few planes with b9-thickness wings , for not much good reason other than that thinner wings make less drag (but in addition to less lift).. I think. I was just fixated on the idea. I like to pretend-pilot. Flight check..uh..nevermind don't know what to do. Pass the freeze-dried ice cream, jeb, we're taking off! Maybe!

Edit : Just guessing, I think that plane could benefit from sweeping more gradually. I bet it's just the transonic effects keeping these wide, thick wings from getting through. I understand you need lots of lift to carry a heavy payload though.

I haven't noticed any flip tendency or extra twitch, but control surfaces are supposed to deflect faster now so maybe that's to be expected, and I have spent more time in the engineering and blackboard replacement department than in the (virtual) air lately.

Edited December 23, 2013 by localSol

[Andon]

You mean sort of like a way to set trim within the SPH?... that'd be pretty slick, actually.

Aye, that's what I'd like. Being able to set a few degrees of trim in the SPH/VAB would be real nice.

[ultrahertz]

When I install Ferram Aerospace 0.12.3 on 0.23 my rocket control surfaces invert their movement. So right becomes left, etc. SAS control wheels start fighting with the control surfaces and eventually the rocket goes out of control. I'm running Mac OSX. Any fixes? Anyone with similar problems?

[krenshala]

I realise that this was with older versions of FAR - but I tried flying lifting body aircraft

Scott, not sure if you hadn't figured it out or just didn't bother for this test/demonstration, but all you need to do to prevent the vehicle from turning back-end over front and "crashing" when you brake is to disable the brakes on the front wheels and let the front wheel(s) just roll out.

Very nice demonstration of how lifting bodies are able to "fly".

[illectro]

Scott, not sure if you hadn't figured it out or just didn't bother for this test/demonstration, but all you need to do to prevent the vehicle from turning back-end over front and "crashing" when you brake is to disable the brakes on the front wheels and let the front wheel(s) just roll out.

Very nice demonstration of how lifting bodies are able to "fly".

Yeah, it's a shame that 0.12 killed these, I did get one lifting body to work but it was under ridiculous circumstances, no pulling out of a dive this time.