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

[StahnAileron]

Derp! Feel a bit dumb... But I was just using the Stock one as an example. I'm not really a fan of B9's aesthetics. (Feels bulky to me...)

I noticed your attempt FAR set-up screen for parts. Just out of curiosity, does FAR look at the TITLE or NAME of parts for those lists? Because this is the cfg settings for the B9 Mk2 cargo bay:

PART
{
    // --- general parameters ---
    name = B9_Cockpit_MK2_Body_Cargo_5m
    [...Removed Stuff...]   
    title = MK2 Cargo Bay 5m (x4)
    manufacturer = Tetragon Projects
    description = CONTAINS 4 SUBTYPES | Large cargo section, part of the long-overdue line of improved parts for the popular MK2 fuselage system. One of the few parts with thermal protection plates painted over the hull. Let's hope that helps with your re-entries.
   [...More removed stuff...]
    MODULE
    {
        name = FSanimateGeneric
        animationName = cargo_mk2_toggle
        startEventGUIName = Close cargo bay doors
        endEventGUIName = Open cargo bay doors
        toggleActionName = Toggle cargo bay doors
        availableInEVA = True
        EVArange = 10
        startRetractEffect = doorMotor
        startDeployEffect = doorMotor
    }
    MODULE
    {
        // 0.86m3 tank
        name = FSfuelSwitch
        resourceNames = Structural;LiquidFuel;LiquidFuel,Oxidizer;MonoPropellant
        resourceAmounts = 0;148;66.6,81.4;148
        basePartMass = 1.06
        tankMass = 0;0.014;0.019;0.01
        tankCost = 0;160;110;190
        displayCurrentTankCost = true
    }
}

Have you tried just the word "cargo" as a term? (I dunno, I'm just throwing stuff out in a sad attempt to help...) Also, looking at the code, maybe the fuel tank property is interfering with the cargo bay property and confusing FAR...???? Which mesh are you using for the cargo bay? Purely structural or as a fuel tank as well? (Could make a difference... Maybe? Dunno... I have the mod, but I'm running NEAR, not FAR, so I can't readily test for you...)

Edited April 14, 2015 by StahnAileron

[blowfish]

Just out of curiosity, does FAR look at the TITLE or NAME of parts for those lists?

It looks for "cargo bay" in the part's title.

[yorshee]

An error keeps popping up in the Debug Menu and it's stopping me from docking, and I think it has something to do with FAR because this is what it says in the output log:

NullReferenceException: Object reference not set to an instance of an object at FlightGlobals.get_ActiveVessel () [0x00000] in <filename unknown>:0

at ferram4.FARControlSys.OnDestroy () [0x00000] in <filename unknown>:0

What's causing it?

[futrtrubl]

An error keeps popping up in the Debug Menu and it's stopping me from docking, and I think it has something to do with FAR because this is what it says in the output log:

What's causing it?

You should give some context. What are you doing when it shows up?

[Kalloran]

Ladies, Gents, and fellow Kerbal Engineers:

So..I recently installed FAR , and B9, (after not being able to for so long...different story). Much to my chagrin, building an aircraft generates no Lift! The little blue Center of Pressure ball has no arrow. Initially I thought this was just a fact that FAR doesn't use the stock lift model, so I checked FAR. My stability coefficients are all good to go and greened up, and an AoA sweep shows good values...but the Mach sweep shows nothing and when I attempt to take off, the aircraft stays diligently on the ground.

I'm sure I'm not the only one who has or has had this problem. Does anybody have any ideas? My modlist is fairly extensive, but if necessary I can gen-up a list.

Thanks folks!

[tetryds]

Ladies, Gents, and fellow Kerbal Engineers:

So..I recently installed FAR , and B9, (after not being able to for so long...different story). Much to my chagrin, building an aircraft generates no Lift! The little blue Center of Pressure ball has no arrow. Initially I thought this was just a fact that FAR doesn't use the stock lift model, so I checked FAR. My stability coefficients are all good to go and greened up, and an AoA sweep shows good values...but the Mach sweep shows nothing and when I attempt to take off, the aircraft stays diligently on the ground.

http://i.imgur.com/QjhEGjE.png

I'm sure I'm not the only one who has or has had this problem. Does anybody have any ideas? My modlist is fairly extensive, but if necessary I can gen-up a list.

Thanks folks!

You are pressing the wrong button, try the "Sweep AoA" instead

The craft is on the ground because your rear landing gears are too far back and because your COL is too far back, so your airplane is actually a lawn dart.

Add some canards and set them to pitch, then move the rear landing gears closer to your COM and have fun.

Edit: more pitch authority could also fix that but then you would have too much stress on your wings.

[BudgetHedgehog]

Also, the no lift arrow is intentional.

[Temeter]

Btw, Is there some easy way to bring the arrow back? The arrow isn't important to show the direction of lift, but it makes it a lot more comfortable to align COL and COM. The latter tends to swallow the former when they get to close, not to mention it's a bit of a chore to play around with the camera, when that helpful arrow just points throught the COM and perfectly displays their disposition.

[Red Iron Crown]

Btw, Is there some easy way to bring the arrow back? The arrow isn't important to show the direction of lift, but it makes it a lot more comfortable to align COL and COM. The latter tends to swallow the former when they get to close, not to mention it's a bit of a chore to play around with the camera, when that helpful arrow just points throught the COM and perfectly displays their disposition.

You should try RCS Build Aid. Among other things, it lets you resize the CoL/CoM/CoT markers for more precise alignment.

[Temeter]

You should try RCS Build Aid. Among other things, it lets you resize the CoL/CoM/CoT markers for more precise alignment.

Thx, got that fantastic mod already. Still an impractical solution, considering the markers are made to overlap.

[Crzyrndm]

but the Mach sweep shows nothing and when I attempt to take off, the aircraft stays diligently on the ground.

Note that you're running the mach sweep between 0 and Mach 25 (in steps of 0.5) with an AoA of 0.2. If you want useful information, you should keep the sweep below Mach 6/7 and give it a few degrees of AoA (you can find your level flight AoA for a given speed/altitude in the static analysis tab)

Edited April 18, 2015 by Crzyrndm

[blowfish]

Thx, got that fantastic mod already. Still an impractical solution, considering the markers are made to overlap.

They get smaller as you zoom in, so you can check their alignment that way. It's pretty approximate anyway, since it will vary with AoA and mach number - to really understand how stable/maneuverable your craft is, you need to actually use the FAR editor analyses.

[Temeter]

They get smaller as you zoom in, so you can check their alignment that way. It's pretty approximate anyway, since it will vary with AoA and mach number - to really understand how stable/maneuverable your craft is, you need to actually use the FAR editor analyses.

I know, I'm playing with FAR for a while now. And I'm pretty sure It still would be around a million times more annoying to build planes without actually having any approximate COL marker. For example, my last plane had it's tail drifting away during some of my maneuvers around 20k 1200m/s. A short check of COL/COM easily betrayed the issue, notably the COL moving too far ahead at a very specfic inclination (that only occured late in flight or during reentry).

FAR is far too good (huehuehue) to not use it, additional markers or not. The arrow is just a small useful thing missing, nothing more, and nothing less.

Edited April 18, 2015 by Temeter

[tetryds]

I know, I'm playing with FAR for a while now. And I'm pretty sure It still would be around a million times more annoying to build planes without actually having any approximate COL marker. For example, my last plane had it's tail drifting away during some of my maneuvers around 20k 1200m/s. A short check of COL/COM easily betrayed the issue, notably the COL moving too far ahead at a very specfic inclination (that only occured late in flight or during reentry).

FAR is far too good (huehuehue) to not use it, additional markers or not. The arrow is just a small useful thing missing, nothing more, and nothing less.

It's not that useful as there is no useful information that comes from it.

What you want is not an arrow, but spikes on the COM and COL indicators, so you can align them better.

Well, I don't think that such feature belongs to FAR, but it would be cool.

As said before, you can get all that info from the graphs and derivatives, the indicator is more like a "oh so it's about here" than anything.

Watch your Mw under different conditions, there you have your ball.

If you want to have a perfect COM/COL alignment, have your Mw=0 or as close to zero as you can, it's infinitely more precise than eyeballing.

[Temeter]

Yeah, I was talking about the spikes. To me the arrow rather served as a big spike in case the COL was below the COM. Implying the (pseudo-)direction of the generated lift isn't really needed, although it's helpful to make the whole construction more intuitive beginners (it was for me).

Writing about the thing, I don't really see why that thing was removed at all. It's a net loss. Well, a very small net loss.

Otherwise I just want to eyeball during construction. Finetuning, if necessary, comes later anyway, and having infinite precision isn't even that usefull if I'm still tweaking the craft and everything might be broken by weight-disposition through fuel usage.

I appreciate the tips, but that doesn't really help the cause. Not that it's even that important, the construction is just a tiny bit more fiddly without it, so I wanted to know if there is a easy solution.^^

Edited April 19, 2015 by Temeter

[Crzyrndm]

@ferram4

Attempting to debug this issue with B9 PWings and FAR (increasing the size of the trailing edge moves the CoP indicator towards the leading edge (compared to a stock wing of the same dimensions as well)). From what I can tell, the parameters being passed to FAR (MAC and surface area being the relevant ones, semispan, sweep, and taper ratio don't change with a rectangular section) are all correct. That leaves me wondering how FAR determines where the wing is located (ie. how does it determine only the back/front edge is changing instead of a symmetric change around the attachment point).

[ferram4]

FAR doesn't change anything there, that's entirely on the pWings to report the proper parameters and where the center of the root chord is. If pWings doesn't adjust those properly, FAR has no hope of simulating it right, because it only runs the values that it is given for wings.

[Crzyrndm]

where the center of the root chord is.

That sounds like the missing element. So it needs to update this as well as the shape parameters I assume.

Thanks for the help

[Naten]

TL;DR: Longitudinal oscillations, how do I fix them?

I'm working with a plane I can't show you (I'm at school ATM) that has all-moving canards and all-moving elevators, as well as a standard delta wing. I made it out of p-wings (all B9 except for the canards, rudder and elevator for allmoving surfaces).

Pitch control causes a longitudinal oscillation. How do I design the aircraft to resist these oscillations and cause it to maneuver smoothly while still being very maneuverable?

EDIT: I almost forgot, with or without canards, the same thing happens.

Maybe lighter wing loading? It's low already. About 10 tons and 62 m^2 wing space, I think.

Reduction of control would only make it less maneuverable.

Also, are supermaneuverable aircraft feasible to make in FAR?

Edited April 21, 2015 by Naten

[gilflo]

Naten

I got super oscillations on longitudinal axis on my last plane until i fixed it by struts

[Wanderfound]

First suspect for pitch wobbles: are you using a PID tuner such as Kerbal Pilot Assistant to correct the awfulness of stock SAS? If not, do.

Second suspect: body flex. If there's any flexing between your cockpit and your control surfaces, they're going to constantly go nuts trying to compensate for it. Use some struts to reinforce each end of the fuselage.

Third suspect: too much control authority. Wind down the maximum deflection until it's no more than what is required (note: how much is required at 500m is often somewhat different to how much is required at 25,000m).

[Hodo]

TL;DR:

Also, are supermaneuverable aircraft feasible to make in FAR?

In short yes.

It is a matter of finding the balance on the CoL and the right speed for that design, much like modern 4th gen fighters.

[tetryds]

Also, are supermaneuverable aircraft feasible to make in FAR?

Check FAR Colibri, it's one of the FAR stock airplanes.

Not the most maneuverable ever (not meant to be), but it can turn a lot.

Using only 1.0 strenght on stock wings, I peaked at the 32g mark (F3 log), as Hodo said, it's just a matter of doing it right.

Flying with a joystick also helps on breaking records, but you won't need it if the design is good enough.

[thorfinn]

"Supermaneuverable" usually means controllability at high AoA, these planes are flying awfully fast but at a moderate AoA...

I have seen people flying in very unusual attitudes though. There is the %AoA deflection setting for control surfaces which is the poor man's stability enhancer, some people used it to good effect (I haven't tried it personally, I'm waiting for 1.0 to restart everything)

[DaMichel]

It might be possible but i figure it is very difficult to pull off.

Concomitantly, controllability at high AoA also means that there is some degree of "post-stall" controllability because at such high AoA the wings will be stalled. Usually this can be done with vectored thrust (need mod for that. 1 deg gimal range of stock engines is not enough. See various airplane part mods). And of course huge and all-moving control surfaces.

The plane should probably be built to be marginally stable or even unstable. The problem with stable planes is getting enough control authority to drive it to high AoA. Also it must be built so that the main wing does not stall before the tail. Otherwise the plane will just pitch down.

AFAIK the first supermaneuverable plane was the Su-27. I watched a documentary where they said that it was actually unstable and used a flight control system with artificial stability assist accordingly. We don't really have that in KSP outside of plugins. Of course the flight control system must be tuned for the specific craft.

Edit: Stupid me. Had to edit the middle section. Better ask the experts ...

Edited April 21, 2015 by DaMichel