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

[Woopert]

Do FAR and procedural fairings get along nicely? I can't even do a simple satellite launch right now without my rocket toppling over at just over Mach 1. I can build and fly spaceplanes / SSTOs no problem... but can no longer launch a simple 3 stage rocket. Very frustrating!

From what I've heard, they do. I think I remember reading on the Procedural Fairings page that they are made to be compatible with FAR (which is the point of fairings, to improve aerodynamics ).

Oh, and just an edit here, it says on the main page of Procedural Fairings that it's compatible with FAR.

Edited January 12, 2014 by Woopert

[ninjaweasel]

From what I've heard, they do. I think I remember reading on the Procedural Fairings page that they are made to be compatible with FAR (which is the point of fairings, to improve aerodynamics ).

Oh, and just an edit here, it says on the main page of Procedural Fairings that it's compatible with FAR.

I thought so, which leaves me with no explanation of why I can't fly a simple rocket anymore. I thought maybe it was the way Mechjeb tries to over control with FAR so I'm trying to hand fly it instead and the results are the same. It's not like I'm doing an aggressive gravity turn or anything, this happens with an 80 degree nose up attitude with no control inputs being applied. Every time: Step 1: Exceed mach. Step 2: Watch the FAR panel go from normal flight to major stall indication Step 3: ??? Step 4: Watch rocket tumble out of the sky.

I like the idea of a harder game and a better atmospheric physics model but this is very frustrating.

[ferram4]

Are you trying to keep the rocket aimed prograde and actually do a gravity turn or are you trying to do the "go up 10km, pitch over like a maniac" ascent that everyone here incorrectly calls a gravity turn?

Is your rocket built vertically? Large, highly parallelized rockets tend to have control issues since as the fuel tanks empty they force the center of mass to move backwards, but keeping larger upper stages in a more vertical serial-staged design results in the CoM moving forward as the first stage drains.

Are you trying to launch a light, fluffy payload that takes up a lot of space in a payload fairing? It's not like a payload fairing is magically protected from aerodynamics; if you're doing something like that it's the equivalent of putting a few wings on the front of your rocket.

Post pictures of your vehicle; without more information no one can guess whether your failure is due to design or piloting. And start small; if you need a payload fairing your fist launch with FAR (which should be a mk1 pod with enough fuel to de-orbit, just like when you started), you're doing it wrong.

[Shad0wCatcher]

Number 3 was my biggest issue; and the way I got around it was to build bigger. I started using larger 3.75 meter rockets or 5 meter rockets with limited thrust and limited fuel, and the skin friction helps stabilize the rocket quite a lot (along with 6.5 meter stabilizer wings *cough*)

[AbeS]

Someone should definitely make a video or something about those common user mistakes while using FAR and be posted in the OP, but I think they would still come here complaining about the mod being broken

[ninjaweasel]

Are you trying to keep the rocket aimed prograde and actually do a gravity turn or are you trying to do the "go up 10km, pitch over like a maniac" ascent that everyone here incorrectly calls a gravity turn?

Is your rocket built vertically? Large, highly parallelized rockets tend to have control issues since as the fuel tanks empty they force the center of mass to move backwards, but keeping larger upper stages in a more vertical serial-staged design results in the CoM moving forward as the first stage drains.

Are you trying to launch a light, fluffy payload that takes up a lot of space in a payload fairing? It's not like a payload fairing is magically protected from aerodynamics; if you're doing something like that it's the equivalent of putting a few wings on the front of your rocket.

Post pictures of your vehicle; without more information no one can guess whether your failure is due to design or piloting. And start small; if you need a payload fairing your fist launch with FAR (which should be a mk1 pod with enough fuel to de-orbit, just like when you started), you're doing it wrong.

- I'm trying to keep the rocket aimed prograde, starting a gentle gravity turn at a fairly low altitude, never letting my attitude leave the prograde vector ball.

- 2 vertical stages with a satellite on the nose, two small boosters on the lower stage which stage prior to the turn (staging while turning hasn't exactly gone well in most cases either)

- The satellite is fairly compact. The fairing diameter is just a touch wider that the rocket itself (2.5m)

I'll get some screen shots and throw them up. I've done several launches of other craft already - this isn't my first launch with FAR by far! I've launched much more complicated vehicles too. Stuff capable of dropping 4 satellites in lunar orbit, or parking a full 3.75m KW tank in LKO as a gas station.

When you say "It's not like a payload fairing is magically protected from aerodynamics" Do you mean that aerodynamics are still acting on the parts inside the fairing as if they were exposed? Or are you talking about the forces being exerted on the fairing itself? I'm aware of how that works (in reality anyway) so I've tried to make the payload as thin as possible to avoid the fairing bulging out wider than the rocket itself. As I understand it, it is undesirable to have a place where the rocket gets smaller in diameter forward of the center of gravity as that shifts the center of pressure forward and reduces stability. (Ever use RockSim? Give it a try sometime, very fun!)

I'm not trying to say to plug-in is flawed. Given the number of people that consider this a must-have, that's obviously not the case. It just feels like I'm back to a fairly "trial and error" place in the game again. I can fly some totally unnecessarily huge and complicated rockets without issue, but can't launch one satellite and can't explain why. Frustrating!

Cheers

[AbeS]

hmm, when you post the screenshots make sure to have MJ showing the stats of the rocket!

If it is just a simple satellite launcher like you mentioned, it makes me wonder if you have a really high TWR? Because if it is higher than 1.2-1.6 at launch it could definetly have issues

[localSol]

Ah nice, have you pictures of it?

I couldn't make the strutting work unfortunately. My current solution is to strut the wings to a heat shield from the THSS pack [...]

Looks cool at least. At one point I was trying disc-oid shaped wings with PWings once it got curved tips, using only tips.

I found an old picture of my sort-of AD-1 and a bunch of other FAR planes over the months : http://imgur.com/a/O8Cjw#0 The only one of the AD-1ish one is disappointing since it isn't swivelling..I don't remember how I attached it back then. Also a Variable sweep plane in FAR, quick Thunderceptor with Pwings, and more , act now while supplies last!

[ferram4]

@ninjaweasel: What I meant by "the payload isn't magically protected by aerodynamics" was assuming that you were a newbie figuring that attaching a payload fairing was the solution to all problems; I've had to deal with a few of those.

I think I see what's going on here; you're relying on the boosters for some manner of stability and it provides just enough to make the rocket work in the lower atmosphere. I have an odd suggestion, but it might work if you're having trouble: put the entire upper stage with payload in the fairing, but attach the first stage to the top of the payload (might need a redesign though) and fly the payload + upper stage up backwards; this puts the heavy engine and fuel in the very front of the vehicle. Put a large probe core on the main stage so you can aim prograde and try that. It sounds wonky, but if it works, you've got an awesome launch vehicle.

Other than that, more fins, and obligatory asking if you're running v0.12.5.2, since v0.12.5.1 and 0.12.5.0 had strange surface area calculation issues.

[taniwha]

ferram4: a bit of a suggestion after watching Scott Manley get bamboozled by FAR's flight assistants (and me laughing because of been-there-done-that). Make FAR's toolbar icon blink if any assistant is turned on and atmospheric pressure is 0 (or below a the threshold where control surfaces aren't any help).

[DaMichel]

@localSol: The sweep wing design looks wicked I noticed that it really works in FAR, meaning that as the wing is swept backwards you can see the drag value drop. Awesome!

put the entire upper stage with payload in the fairing, but attach the first stage to the top of the payload (might need a redesign though) and fly the payload + upper stage up backwards;

This is a great tip. I've got to try that some day, too.

My approach for unstable rockets / bulky payloads has always been to use the "n00b" stock ascent profile, climbing to 10km, after that *very gently* putting the nose down, which gets me high up but with low orbital speed obviously. I also use SAS right from the start and have lots of RCS and some fins with control surfaces to keep the thing on course. In no way elegant or efficient but it works ... mostly

[not-a-cylon]

I finally did it! I designed a spaceplane with a TWR under 1 and brought it to supercruise! Pictured here is the the plane throttled down to 0.476 TWR (the full throttle is under 1) in a shallow climb at mach 4 and rising. I suggest everyone playing with this mod to challenge themselves with designing aircraft with a TWR under 1 (or throttling the craft under 1 TWR the entire flight) to supercruise. It forces you to fully exploit aerodynamic principles instead of relying on brute force engine power to make your planes fly.

Sorry for the night shot. It takes a while climbing to the appropriate cruise altitude, like in real life. The SR-71 blackbird had a TWR of 0.382 and had an interesting way of getting to super cruise as described here.

Added a daytime shot without the UI. It's comfortably cruising at mach 5.129 at around 32,000 meters with a TWR of 0.327.

Edited January 12, 2014 by not-a-cylon
added picture

[Tic-Tac]

Hi,

i'm having some issues with Ferram, I only have KSP interstellar, KW rocketery and Engineer installed, and when FAR is installed, my reentries goe terribly wrong.

I first had the problem with a lander that came back from the mun, it was a basic cockpit, with a material lab, four goo containers, four temperature scanners and seismic scanners, and 3 chutes.

When it started getting in atmosphere, it lost most of it's velocity REALLY fast, and without any reentry effect, and it started falling really fast (It went from about 3000m/s to 30m/s, within something like 30 seconds), and when you are at 30 000 meters high, 30 m/s is a really long descent speed...

And it happened then with every other reentry I had.

It seems that when I make it go into physical time warp, the vessel shakes really fast but only a bit, and It also seems that I almost can't control rotations with the reaction wheels, the vessel stays fixed in the prograde direction...

Help?

[Wayfare]

Hi,

i'm having some issues with Ferram, I only have KSP interstellar, KW rocketery and Engineer installed, and when FAR is installed, my reentries goe terribly wrong.

I first had the problem with a lander that came back from the mun, it was a basic cockpit, with a material lab, four goo containers, four temperature scanners and seismic scanners, and 3 chutes.

When it started getting in atmosphere, it lost most of it's velocity REALLY fast, and without any reentry effect, and it started falling really fast (It went from about 3000m/s to 30m/s, within something like 30 seconds), and when you are at 30 000 meters high, 30 m/s is a really long descent speed...

And it happened then with every other reentry I had.

It seems that when I make it go into physical time warp, the vessel shakes really fast but only a bit, and It also seems that I almost can't control rotations with the reaction wheels, the vessel stays fixed in the prograde direction...

Help?

I had the same issue with a probe today. If you go into the FAR flight data menu when this happens you'll probably see some absurdly high number at "reference area". Basically, FAR erroneously assumes your craft has an enormous surface area. Combined with its (relatively) low mass, it descends like a sheet of paper rather than like a spacecraft on ballistic re-entry

Updating to FAR 12.5.2 fixed it.

[biohazard15]

I've decided to try FAR today - just out of interest. I'm designing my rockets to be "as realistic as possible" - which means vertical design, fairings, debris reduction systems (OK, that's not a real feature... yet) etc.

This mod is AMAZING.

This is my Vanguard II heavy launcher, designed as "100-100" rocket (which means 100 tons to 100 km orbit). Two-and-half stage asparagus, somewhat like Falcon 9 Heavy. Here it shown with a 80-ton refuel vessel payload (second stage is used for rendezvous maneuvers).

It was built for stock aerodynamics, without FAR in mind.

1nd stage: 3x 4900 kN engines (1x after boosters separation) (KW Griffon XX)

2nd stage: 1x 1800 kN engine (NP Little Mother)

Without FAR, this rocket ends at 100km with about 1\4 LF\O left in second stage.

With FAR, this rocket flies BETTER than in stock (completely stable, that is) and ends at 100 km with 85% of its 2nd stage LF\O.

I feel myself as a cheater now

BTW, don't look at dV stats - it's completely messed up due to some bug in MJ (my best guess is that MJ doesn't like it when you build rocket "from bottom to top" - and this is how I build my rockets. Weight and TWR is correct for 3rd and 4th stage, though)

[DaMichel]

I finally did it! I designed a spaceplane with a TWR under 1 and brought it to supercruise! ... snip ...

Have you tried KSP Interstellar? They have nuclear powered atmospheric engines which have really low TWR but don't need oxygen. It is a challenge to build a space plane around them, but when you succeed you have a craft which can operate on any planet with an atmosphere. (Anti-Matter Engines are probably OP. Try it with fission/fusion reactors.)

[MAKC]

ferram, is the control surface stall angle functionality still in? I can't seem to figure out how to do it with the tweakables menu.

[ferram4]

It's not; I removed it when I cleared out the control surface GUI. I'm honestly not sure where I would add it back in.

[Dr. Death]

there are several things i dislike, so i will just post them as feedback:

-After your last aerodynamics update, most of the aircrafts that come with the mod flip out very easy, as all of them have just too much lift. (the aircrafts that i think are the most stable are the transport one and the blackbird, nice aircrafts BW)

-Planes not made for supersonic speeds should have severe damage when doing supersonic, the husky transport should experience tearing because of the effect and pressure.

-Husky transport reach up to 20 kilometers of Alt. while the black bird reaches 13-15 k

-The blackbird should be able to reach for 20 kilometers, but that's more of the atomsphere limit.

-Many of the aircrafts have problems when you want to get back in, there is no way to do it

Now, those are the problems that i think can be fixed. But i have 2 more suggestions:

1- try to get a more aerodynamic air intake for the blackbird, with the deadly reentry effect mod (wich if you dont want to, you dont need to do this because its about co-operation between 2 mods) the blackbird can't reach more than Mach 6.2 or around that speed before tearing itself apart. Also, the blackbird loses control at 13 kilometers and after 15 kilometers over steering it a little bit can cause severe stalling and lose of control.

2- the wind in real life its not something the pilot has to deal with to avoid stalling, its the other way around, in real life a pilot wont stall unless going really slow because the air is avoiding the pilot to get into a stall by forcing the plane to aim for the direction the air speed is going. That's why if you see pilots before fly-by-wire they had to pull the stick with a lot of force, because the air was not letting them move the plane. With this mod, you are the one that have to aim for the ball all the time if you dont want to flip.

TL;DR: Air is too light, it should be stronger and force the plane to avoid stall.

[Surefoot]

-Planes not made for supersonic speeds should have severe damage when doing supersonic, the husky transport should experience tearing because of the effect and pressure.

I dont think that would be this mod's responsibility but rather something like Deadly Re Entry. FAR only models aerodynamics, not tearing or other mechanical constraints.

(...) Also, the blackbird loses control at 13 kilometers and after 15 kilometers over steering it a little bit can cause severe stalling and lose of control.

While i agree it should be able to go higher (but that's more from a limitation of what you can do with stock parts), the real one is also very unstable and needs the SAS to be activated (yes there is one in the SR-71, exactly named like that). Very few pilots dared to turn it off... Going just a tad too far on AoA means unrecoverable stall.

TL;DR: Air is too light, it should be stronger and force the plane to avoid stall.

Not sure what you mean by that, FAR is as realistic as it comes before going for something like X-Plane.. The stalling behaviour is quite realistic actually (so are the "expanding spiral" and other aerodynamic features like "dutch roll"). I dont think many sims reach that level of realism.

[Castun]

I also had an odd issue with a spaceplane that would start to spin out of control in outer space even with SAS enabled, might have been from a flight assistance being left on or something though.

On another funny note, it's not even meant to be a spaceplane, just a small jet with 2 engines that I designed, that ended up reaching a 178km apoapsis because it reached a good 2,400m/s at 35km. Stock engines are definitely OP I would say.

[ferram4]

there are several things i dislike, so i will just post them as feedback:

-After your last aerodynamics update, most of the aircrafts that come with the mod flip out very easy, as all of them have just too much lift. (the aircrafts that i think are the most stable are the transport one and the blackbird, nice aircrafts BW)

Yeah, most of them need a bit of a redesign. The Jet Airliner has been properly redesigned, the SR-71 is exactly correct to the best of my ability. The Thunderbird is deliberately unstable, since it's a maneuverable jet fighter.

-Planes not made for supersonic speeds should have severe damage when doing supersonic, the husky transport should experience tearing because of the effect and pressure.

Oh, sure. I'd love to add proper aeroelasticity and flutter, but haven't gotten to that yet. The best part is that adding that will lead to aileron reversal effects (go too fast with wings that are too thin and the ailerons cause the wing to bend so much that the plane actually rolls the other way). Lots of rage will occur once that is implemented.

-Husky transport reach up to 20 kilometers of Alt. while the black bird reaches 13-15 k

-The blackbird should be able to reach for 20 kilometers, but that's more of the atomsphere limit.

[camlost]

ferram,

Is the CoL offset we experience during sub-sonic and supersonic flight working properly now? Flying the SR-71 I find this effect much smaller than previous versions, negligible tbh.

Also I realized that the jet engines are completely overpowered. In real world the thrust decrease a lot while the aircraft climbs to a certain altitude. However no mod has corrected this. As a result the whole thing was just too easy and completely absurd.

[ferram4]

The CoL doesn't shift quite as much, mostly the previous transonic instability was lessened. It is there, but on something that gets large amounts of body lift (like the SR-71) the effect isn't as noticeable.

The second part can be fixed by taking the code from my post above yours and putting it into the FerramAerospaceResearch config where the turbofan code is. I goofed.

[Castun]

@Castun: yeah, it turns out there's a bug in the Turbojet module manager fix. It needs to be changed to this:

@PART[turboFanEngine]
{
    @MODULE[ModuleEngines]
    {
        @maxThrust = 200
        @velocityCurve
        {
            @key,0 = 0 0.7 0 -0.00098

            @key,1 = 140 0.63 0 0

            @key,2 = 400 0.7 0.00049 0.00049
            @key,3 = 900 1 0 0

            key = 1800 0 -0.00098 0
        }
    }
}

Good, I'll patch that in and see what it does to the engine. I did a couple orbits and was able to increase my apoapsis to well beyond the Mun!

Also, I'm pretty sure the issue with my jet spiraling even in outer space was due to a controller I forgot was plugged in and wasn't centered, so it was giving the slightest bit of upward input.