Thinking about making the switch to FAR.

[capi3101]

Intercoolers? Never heard of thems - are they one of the new stock parts? The wiki hasn't been updated yet and I haven't played around too much in the litterbox with 1.0.2.

[Hodo]

Intercoolers? Never heard of thems - are they one of the new stock parts? The wiki hasn't been updated yet and I haven't played around too much in the litterbox with 1.0.2.

Yeah they replaced the inline intake.

Here is a picture of what the NUFAR or FAR.15.1 looks like with everything on.

Notice the little purple/pink lines? Those are the voxel lines or how the "air" will flow around the craft. The key thing for a stable craft you want that yellow line as smooth as possible and the green line to be equally uneventful, you definately do not want major spikes in either line but a smooth transition for the green line and a smooth nearly flat yellow line.

[Wanderfound]

Intercoolers? Never heard of thems - are they one of the new stock parts? The wiki hasn't been updated yet and I haven't played around too much in the litterbox with 1.0.2.

They're useful but high-tech; you won't have them in your career game yet. Bit of LF, bit of intake, good heatsink properties. They're the bits just in front of the engines on this one:

[capi3101]

Ah, okay. Like I said, I haven't really taken the time to look at all the redesigned parts. I really oughta if I can get more than one hour per day to play...

Alright - revised design of the Screwup 7 (this would be the Screwup 7a, of course):

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I'm guessing from the voxels that the extra wave drag (the amount over the max cross section, I mean) is coming from up there at the girder holding the LES rocket to the nose. I'd dump the whole thing and replace it with a proper nose cone (nothing else to put there that'd be useful at the moment, not even a Circular Intake), but of course the point of the craft is to test the LES in atmosphere, so...at least I got the wave drag area down. Critical Mach number changed in the wrong direction...

I take it the spikes in the yellow line come from the bush plane landing gear, and then in the way back it's the combination of the tail and the Thuds? I probably oughta take some sci to invest in some proper retractable gears in the near future...maybe go for Landing next up after Aerodynamics.

I recall somebody on the main FAR thread saying something about the new FAR not placing the position of the CoL ball correctly - I'm forced to wonder if that's affecting me with this plane. I'd say something except A) it's already been said, at least I think so, and I don't have a flight log to report so anything I could say wouldn't be helpful. All I know is that I had the main wing down first, then added the Tail Fins forward, then the AV-R1s forward of those, and the CoL marker didn't budge. The plane still had pitch-up tendencies as it was, which probably could be fixed by moving the main wing aft. I did do the test run last night and everything was ok up until the test was successfully completed and the rockets were switched off. The jet had flamed out from lack of air and the plane slowed to subsonic speeds, and then proceeded to pitch up and enter a spin. Tore the main wings off in the attempt to recover, leaving me without roll authority...though I damn near was able to recover enough control to return to level flight (at least I thought I was about to a couple of times).

Comments? I'm pretty sure there's not much else I can do with this particular plane that y'all haven't already told me to do (move the CoM forward, move the wing back, etc.) or that I can do at the present time. Maybe move the LES to the back. I don't know. Fueling the LES would bring the CoM forward; at the moment it's empty.

[capi3101]

So, it looks like I need to learn how to fly once again...

Last night I went ahead and ported my craft from my 0.90 litterbox into my 1.0.2 litterbox. I had to go ahead and port over the Large Gear Bay part as well in order to get those craft to load up properly, so I have that now even though it's no longer necessary given the new larger wheels and I'll switch the craft that were utilizing the Large Gear Bay over to stock 1.0.2 gear if/when I plan on using any of those craft on a regular basis again. After that I decided to have a go with a craft that made orbit successfully in 0.90 FAR. The first one I chose was the Tylenol 7, the same plane I got into orbit in this post on page 25 of this thread. Here's a pic of the trans-sonic wavy-lines graph thingie:

Pretty sure that hump in the green line is being caused by the under-slung engine nacelle assemblies. I should take a screenie with the numeric trans-sonic properties of the plane and voxels on just to see what all it's doing.

The problem I've got now is the new characteristics of air-breathing engines in atmosphere. This was a plane that was able to get up to Mach 4 and 30k prior to 1.0; last night she struggled to get past Mach 2.7 and 25k, while simultaneously if I started the engines up at full throttle I'd have far too much thrust at takeoff and rip things off the wings (last night it was one of the flaps that went). Can any of y'all give me a quick lowdown of the new limits I can expect from air-breathing engines as well as what is now a reasonable spaceplane ascent profile?

Got the Tylenol to its new limits three times before I decided to just go for it. I got the plane's Ap up to 70k but circularization would've required 800 m/s of delta-V, and it simply didn't have that much fuel left at that point - not even close. I'm assuming the underslung nacelle design is out at this point given the new wave drag generation feature.

An overview of rocket flight would also be nice as well; I've been following the guidelines for new stock aero rocket launches for 1.0 and those have worked out...okay. My rockets want to oscillate as I make my way towards 45 degrees at 15k but once I get there it smooths out as a rule. I'd like to figure out how to make the flight nice and smooth the entire way, though. I've also had issues between FAR and StageRecovery - they appear to not be playing nice with one another after I started using Fanno, despite having something like 24 side chutes and a powered probe core on the stages (i.e. something I could recover - and occasionally have recovered - were I to do so manually.)

[ratchet freak]

So, it looks like I need to learn how to fly once again...

Last night I went ahead and ported my craft from my 0.90 litterbox into my 1.0.2 litterbox. I had to go ahead and port over the Large Gear Bay part as well in order to get those craft to load up properly, so I have that now even though it's no longer necessary given the new larger wheels and I'll switch the craft that were utilizing the Large Gear Bay over to stock 1.0.2 gear if/when I plan on using any of those craft on a regular basis again. After that I decided to have a go with a craft that made orbit successfully in 0.90 FAR. The first one I chose was the Tylenol 7, the same plane I got into orbit in this post on page 25 of this thread. Here's a pic of the trans-sonic wavy-lines graph thingie:

http://i.imgur.com/aanwN3K.png

Pretty sure that hump in the green line is being caused by the under-slung engine nacelle assemblies. I should take a screenie with the numeric trans-sonic properties of the plane and voxels on just to see what all it's doing.

You should probably add a vertical strake in front of the rudder to fill out the "valley" behind the large hump of the nacelles

[Wanderfound]

The girder nose isn't helping, but most of your drag is coming from the tail. Ignore the CoL marker; it'll just confuse you. Rely on the stability derivatives instead.

Underslung engines still work, but you need to do them right. Small adjustments of position can have large effects on drag.

[Wanderfound]

The new flight profile:

1) As steep as possible to 10,000m.

2) Flatten off and accelerate to Mach 4 while slowly climbing to 20,000m. Steepen the climb if overheating, shallow it out if too slow.

3) Once over 20,000m, you will rapidly lose jet power. Light the rockets and pull the nose up hard as soon as you start to lose speed.

You do need to push the heating limits a bit if you want to get the best out of your jets.

Edited May 19, 2015 by Wanderfound

[capi3101]

20k? Oof. I had trouble enough making orbit with planes going Mach 4 and 30k in the old FAR...

I'm playing on an ultra-low end box and I've got the visual heating effects largely shut off to save a bit on memory. So, being able to tell when my plane is starting to overheat is going to be a little problematic; any way to guess if/when I need to start steepening up the climb (other than waiting until I've got parts exploding)?

How about fuel - are you all able to get away with the same fuel requirements as you used to be able to do in pre-1.0 FAR? Or have you had to add more? With the Tylenol I was doing Mach 2.7 at 25k before I lit the rockets, so I'm assuming my failure to get into orbit was due to a crummy flight profile at that point.

[Wanderfound]

If you don't have the overheat gauges disabled, their appearance is a cue to lift the nose. Alternately, Kerbal Flight Data gives temperature warnings as well as other useful things.

20km is when the jets start to lose power, but you keep accelerating (rockets off) until 25,000m or so if you've done it right. You will need a bit more oxidiser than before, but the jets have twice the thrust of old FAR, so you should be carrying less engine and wing.

[capi3101]

Ah, okay; that definitely explains the behavior I saw on the Runway with the Tylenol. I'll have to run the same engine test I did a while back to see just how much the engine thrust has changed. 0.75 still a good TWR to shoot for on the Runway?

I had been told in the past that I should shoot for a static wing loading of about 0.3 tonnes per square meter; is that figure still good or should I adjust it to something a little higher? It strikes me that 0.3 would produce a wing that has a fair amount of potential for wave drag if you don't stick everything in the right spot. I dunno.

[eddiew]

I think you can get away with lower now, tbh; TWR seems to be taking second place behind low drag with nuFAR

I've been refining

so that it now actually gets to orbit with a red tank. Runway TWR I think starts at 0.55-0.59, but I'll check when I get home tonight. Point is that that is a horribly inefficient and draggy design and yet it flies with 20T per rapier; a sleeker plane would do far better I'm sure.

- - - Updated - - -

If you don't have the overheat gauges disabled, their appearance is a cue to lift the nose. Alternately, Kerbal Flight Data gives temperature warnings as well as other useful things.

Potentially useful observation; if you can get to 18km without anything kersploding, you tend to be ok. I'm consistently getting planes to 900-1200m/s with intake temperatures around 1800-1900 degrees, but they start to cool after this altitude, even if you continue accelerating

There's a tiny mod Thermal Monitor that puts the temperature of a part on the right-click menu by default, rather than having to turn it on via debug every flight.

[Wanderfound]

Ah, okay; that definitely explains the behavior I saw on the Runway with the Tylenol. I'll have to run the same engine test I did a while back to see just how much the engine thrust has changed. 0.75 still a good TWR to shoot for on the Runway?

I had been told in the past that I should shoot for a static wing loading of about 0.3 tonnes per square meter; is that figure still good or should I adjust it to something a little higher? It strikes me that 0.3 would produce a wing that has a fair amount of potential for wave drag if you don't stick everything in the right spot. I dunno.

This sort of formulaic approach to aircraft design simply doesn't work. It's all about balance and compromises and the right tool for the job.

You need enough TWR to reach takeoff speed before the end of the runway. How much that is will depend a lot on the takeoff speed of your ship. This will, in turn, depend a lot on your lift (and is therefore related to your wing loading). But those wings generate drag and are dead weight in space...

How much wing always depends on what you plan to do. Heavy loads call for bigger wings, high speeds call for smaller wings. Straight-line speed wants high wing loading, high-G aerobatics wants low wing loading. Big wings aid low-speed fuel efficiency and stability, and make it a lot easier to land. But they waste more oxidiser when the rockets are burning, reducing ÃŽâ€V in orbit.

"What's the best" is always "best for what?".

You don't need a lot of engine if you can get your drag under control:

Edited May 21, 2015 by Wanderfound

[capi3101]

Hey Wanderfound, saw your question about the simulations over on the FAR thread - basically, all you have to do with the simulations is to plug in an initial value for a given parameter, run the sim and look at what the graph does (the actual details are unimportant). If it oscillates but either holds the same amplitude or damps down from left to right, your plane is stable on that axis. If the oscillations increase or if they immediately fly off to who knows where, it's unstable on that axis. I usually run a sim on a parameter only when I've got a red number; the sim lets me know whether or not it's something I can live with or if I have to fix.

Don't know what the crap is going on with your plane, though. I could try replicating it and see if I get the same behavior. What all do you have in the Service Bay? Is that a Mk1 tank ahead of the FL-T800? The tail is a pair of AV-R8s, right? What about the gear?

I have noted that the new FAR doesn't always put the CoL marker in the right spot, which is a bite.

I did run a new sandbox design last night; I was using B9 procedural wings with it though, and I didn't see the updated .dll until this morning, so I might try again with the design before I ask more about it. She got up to Mach 3.2 at 20k before I lit the rocket; wouldn't pitch up with the rocket lit, though, so she failed to make orbit.

Also ran an empirical test of the engines - Basic Jets now provide 106.35 kN on the Runway, Turbojets provide 166.77 kN on the Runway, and RAPIERs provide 129.34 kN on the Runway. My testing rig was a Ram Air Intake, small RGU core, Mk1 Fuel Tank, Tri-Adapter and one of each engine type, held to the Runway by a pair of launch clamps. In playing around with that data, I'd agree that 0.75 TWR is a bit much these days (though that still jives with the notion of excess thrust covering a lot of sins, something that I've found is still applicable as long as you don't blow anything up in the process).

Did manage to get a little do-nothing single RAPIER spaceplane into orbit after I grabbed this data. My first successful 1.0.2 FAR plane orbital flight. Still working on getting six-tonne probe transporters into orbit.

Edited May 26, 2015 by capi3101

[Wanderfound]

Hey Wanderfound, saw your question about the simulations over on the FAR thread - basically, all you have to do with the simulations is to plug in an initial value for a given parameter, run the sim and look at what the graph does (the actual details are unimportant). If it oscillates but either holds the same amplitude or damps down from left to right, your plane is stable on that axis. If the oscillations increase or if they immediately fly off to who knows where, it's unstable on that axis. I usually run a sim on a parameter only when I've got a red number; the sim lets me know whether or not it's something I can live with or if I have to fix.

Don't know what the crap is going on with your plane, though. I could try replicating it and see if I get the same behavior. What all do you have in the Service Bay? Is that a Mk1 tank ahead of the FL-T800? The tail is a pair of AV-R8s, right? What about the gear?

I have noted that the new FAR doesn't always put the CoL marker in the right spot, which is a bite.

Yeah, it's a basic Mk1 LF tank followed by an FL-T800; my standard Mk1 spaceplane layout. The stabilators are tailfins rather than AV-R8s. Standard small gear, with the rear gear mounted on hardpoints under the wings.

Thanks for the help on the simulations; I'll have a bash at it tomorrow and get back to you if I'm still confused. What sort of values should you plug in as the parameters? What units are they measured in?

I don't even bother to turn the CoL marker on these days; it's useless. Just get the pitch-up stability derivatives green and you're all fine as far as wing positioning goes.

The yaw problem only seems to happen with delta-wing designs; I think it might be just a matter of the wings blocking airflow to the vertical stabiliser to the point that it loses yaw stability at altitude. Take the same design and shrink the wings and the yaw issues disappear:

Cranking the wing loading that high makes it extremely unfriendly to novice pilots, though.

Oh, and the service bay was for this:

Did manage to get a little do-nothing single RAPIER spaceplane into orbit after I grabbed this data. My first successful 1.0.2 FAR plane orbital flight. Still working on getting six-tonne probe transporters into orbit.

Congrats!

Edited May 26, 2015 by Wanderfound

[capi3101]

Yeah, it's a basic Mk1 LF tank followed by an FL-T800; my standard Mk1 spaceplane layout. The stabilators are tailfins rather than AV-R8s. Standard small gear, with the rear gear mounted on hardpoints under the wings.

Cool. I'll give it a go and see what happens with it when I get an opportunity (probably after 00Z at the earliest, and that's if the missus/childern don't have anything to say about it)

Thanks for the help on the simulations; I'll have a bash at it tomorrow and get back to you if I'm still confused. What sort of values should you plug in as the parameters? What units are they measured in?

As best I can tell, the units are dimensionless. That's an assumption; I'd have to do more research to say one way or the other. Generally though, I just plug in a value of 5 into the parameter I want to test and and let the simulator go; with the default setting, this puts the initial starting point of the parameter about halfway up the positive side of the vertical axis. FAR then draws the graph for that parameter based on the initial set of conditions fed to it.

I don't even bother to turn the CoL marker on these days; it's useless. Just get the pitch-up stability derivatives green and you're all fine as far as wing positioning goes.

Okay. The W is all green - I can do that.

[Wanderfound]

Okay. The W is all green - I can do that.

With the slight addendum of the more pitch stability you build in, the more pitch authority you'll need to overcome it. Overly rear-lifted ships are a nightmare at takeoff.

Ideally, shift the wings back until the derivatives go green, but no more.

[capi3101]

Okay...so here's what I did:

I missed where the air intakes were on your plane and the wings aren't quite as far back, but other than that I think it's a faithful replica. I did notice the same kind of behavior you were describing with the design, a catastrophic loss of yaw control around Mach 3 at 10k. Also noticed the same behavior around 20k in the Mach 3-4 regime, this with the game green-lighting the stability derivatives at my usual benchmark levels. So I went into the simulator and ran it at 10k/3 with the initial r parameter set to 5 - and I got a graph with increasing oscillations with time. Same occurred at 20k/3. At 30k/4 the graphs were flying out the window. The crapper of it is that ordinarily I wouldn't hit the simulators unless I had a red light (you know, a bonafide reason to go to the graphs), and at all of the benchmarks the numbers stayed green...

I thought I'd taken screenies - could've sworn I'd taken a bunch of them - with the graphs open. For some reason I don't have them.

Didn't do anything else spaceplane wise last night, though it turns out I did take a screenie of my little do-nothing plane:

Caveat on the design: I wasn't expecting to make orbital altitude ...which is why it ran out of electrical power before I could make the insertion burn.

Last thing I'll post this morning is the Javelin, an experimental design I was playing around with:

I'll admit that this one was me solely going by formulas again and forgetting the lessons of the past, though I think if I change the design from where the jets are slung under the wings to where they're more flush with the fuselage it has a fair amount of promise. Six tonne probe lifter, made Mach 3.5 by 25k, failed due to insufficient pitch authority after I lit the rocket. Haven't adjusted the design at all since the initial flight; I'm thinking canards and strakes; the root of the wings is not as long as I'd have liked. I was shooting for a takeoff TWR of 0.75 (which has since been established as "a bit much), a wing loading of 0.6 (comparable to the Shuttle), a wing aspect ratio of 2:1 (again, comparable to the Shuttle) and ~1,350 in rocket delta-V (assuming I'd get the design up to 1000 m/s before I had to switch over). Those are B9 procedural wings I'm using there, and that was before yesterday's patch was released.

(The "backwards command module" in the screenie, incidentally, is being caused by the payload - all I had in there was an NRAP test module set to six tonnes, which was indeed pointed aft.)

Edited May 27, 2015 by capi3101

[Wanderfound]

The intakes were near the back of the wings, under the fuselage; I often use them to smooth the drag transition between wings and tail.

I tried adding strakes to the Minithud (the red thing above) to give it a more reasonable stall speed. Same thing: perfect until it gets up to speed, then instant explody death. Looks like deltas are a high-risk option until we figure it out.

I'd be surprised if an oversized vertical stabiliser doesn't sort it, though.

That unicycle tailwheel is less than ideal, BTW; rolling your wings out of level mid-takeoff ain't good. A pair of wheels either side of the fuselage will protect the rear just as well, and will also be much more stable.

Electric drain is a perennial problem with RAPIER ships, thanks to the lack of an alternator. I always stick a few batteries in the cargo bay.

Edited May 27, 2015 by Wanderfound

[capi3101]

Last night I had a thought. I'm not quite sure what FAR is using voxels for - my understanding is that they're measuring drag on certain parts of a craft. All I know is that you want to try to keep the green line as smooth as possible and the yellow line as flat as you can manage. That brought me to the notion of sticking a pair of Thuds on either side of a Turbojet; it seemed to me that sort of setup would generate a fair amount of drag near the engine. Right before I made the switch to FAR, my stock Turbojet engine setup used 24-77 engines for rocket thrust, which y'all talked me out of using because they were "draggy parts". Given the new wave drag model of new FAR, I wanted to investigate if that setup was still a bad idea. So I built a testing rig - a Ram Intake, Probe core with battery, fuel supply, and Engine Nacelle and whatever engine combos I wanted to put with it. I tested a RAPIER by itself, the Turbojet/pair of Thuds (Mk-55s) setup, and a setup for Turbojet/Twitches (24-77s) that produced a comparable amount of thrust as the combined Thuds (240 kN). Since they've been reduced to 16 kN each, that works out to 15 Twitch engines - 16 was easier to build (just stick the SPH into Radial mode, set it for 8x symmetry and put two sets on). Here are the results:

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The Twitch setup produced more thrust, more delta-V, less mass and less overall drag; the tradeoff is higher part count and higher expense. I decided to try it out on yet another transporter spaceplane:

Crummy screenies - I know - but they were the only ones I had that were any good at all.

I didn't like this design much. Static wing loading was around 0.6 (on purpose) and TWR on the Runway was 0.51 (I was shooting for 0.55). In flight, it didn't want to do much past Mach 3 at 20k - and I had to dive from a higher altitude to get it to go that fast in the first place. I suspect it would've done better as a dual-engine plane. I also didn't optimize the craft's wave drag curves - a horrible thing to neglect when you know you haven't got a lot of excess thrust in the first place. Finally (and this is embarassing) I didn't add a dedicated liquid fuel load. The plane made orbit but it ran out of its own fuel in the process and I had to cannibalize the payload to make it work. I do think the design has potential, though. I just need to make some serious tweaks - like smoothing out the fuel fuselage, removing the gap between the wing and the engine or filling it in, maybe shuffling the canards around a bit, adding some damn liquid fuel, replacing the Engine Nacelle with a Pre-cooler, and so on. It has an all-moving fin; that was laziness/lack of time on my part and something I should take some time to correct. This one also has a support unicycle wheel to curtail the risk of tail strike; I'll try replacing it with a pair of wheels and see what that does (if anything; I wasn't convinced that kind of setup was strictly necessary with this particular plane). Should also take some SPH screenies too.

Edited May 28, 2015 by capi3101

[Wanderfound]

Last night I had a thought. I'm not quite sure what FAR is using voxels for - my understanding is that they're measuring drag on certain parts of a craft.

You probably know this, but just in case: a voxel is a volumetric pixel. In other words, voxels are what you use to build a 3 dimensional model out of tiny little cubes.

In the stock game, lift and drag are calculated for each piece individually, then summed for the whole craft. A stock aero ship is essentially a collection of separate parts flying in close formation. In FAR, the mod instead creates a 3-D model of the entire ship (this is the voxel bit), then works out the aerodynamic properties of the shape as a whole. Doing it this way allows FAR to account for part clipping and rotation: in stock, a wing sunk halfway into the fuselage works exactly the same as one that's fully exposed. In FAR, only the bit of wing exposed to the airstream will have an effect. This also allows FAR designers to construct their own cargo bays etc from structural parts and have them properly shield their contents.

The "lots of Twitch radials" approach will be better in some circumstances, but not all, thanks to the area rule stuff.

The way to get your wave drag down is to minimise sudden changes in cross-sectional area. However, a conventional mid-wing design nearly always has a sharp drop in cross section immediately behind the wings, which then goes up again as it hits the tail empennage.

Sticking a few relatively bulky parts (Thuds, radial intakes, landing gear, mystery goo, monoprop tanks etc) in between the wings and tail is a good way of filling this gap. Most of my mid-wing turbothud ships actually generate more drag with the Thuds removed than with them in place.

Drag needs to be considered holistically; the drag of a constructed FAR ship is not the sum of its parts.

[eddiew]

This also allows FAR designers to construct their own cargo bays etc from structural parts and have them properly shield their contents.

I. Never. Thought. Of. That

What a pro for nuFAR... the door is open to me! Up to about 150 parts, when lag will close it again.

Roll on Unity 5 performance improvements.

- - - Updated - - -

Electric drain is a perennial problem with RAPIER ships, thanks to the lack of an alternator. I always stick a few batteries in the cargo bay.

I've been placing basic solar panels on the wings, then sneakily sliding them down until they are a 'pixel' above the surface. They still work, and FAR reports them having less drag for bothering to do so. Given that the underside is an air-gap anyway, I don't feel this is too cheeky

[SAI Peregrinus]

A stock aero ship is essentially a collection of separate parts flying in close formation.

And because of that, this thing can get to orbit without problems. It's a bit hard to see in this shot, but all the parts are offset enough so as to not be touching at all.

[capi3101]

Alright - another day, another new design:

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I did intend to try out a cranked arrow design with a traditional wing and tail configuration. The V-tail, however, was a spur of the moment decision.

This design was almost successful - it made it into orbit under its own power and launched a fully-loaded payload without issue. But, it didn't have enough Oxidizer afterwards to de-orbit. I'm guessing my flight profile had something to do with that, though (maybe I lit the rockets too low), so I'm going to try again tonight.

The main thing I'm worried about at the moment is whether or not the plane will still be dynamically stable after fulfilling its mission (i.e. during descent and landing). It strikes me that the main wing may be a bit too far forward, and RCS Build Aid is telling me the CoM is going to shift back quite a little ways (the RCS you're seeing in the SPH screenies is for the probe; the plane itself has no RCS capability). Makes me wish I could rely on the CoL marker to be accurate. FAR green lit me up to 30k/M4, but that was with tanks full. I might see what it says with tanks empty before I try the next launch. Maybe put the wing a little further back (it's not like I don't have plenty of room to do that) and move the Mk1 Fuselage tanks forward.

I am pretty sure something was borked with my instance of KSP last night - I had some weird behaviors going on later on when I switched over to my career game. The NaN readings I was getting from KER were not a good sign either. Couldn't tell if the voxels I was seeing with the Ballista's wings were good or not; I know there have been issues between B9 Procedural Wings and FAR.

Edited May 29, 2015 by capi3101

[eddiew]

You do love dem drones I also note your style is evolving in positive ways! Oh those early days of un-planey planes... /nostalgia

Anyway, NaN from KER seems to happen when it doesn't understand your fuel tanks. In 1.0, KSP can now draw fuel from any part of the ship, but KER doesn't know about that rule and when it sees there is some fuel left but doesn't think it's accessible by the engine(s), you get a NaN. Fuel lines tend to resolve it

Are you filling the wings with fuel? If not, that might get you your extra delta-v to come home