The 5th Generation Fighter challenge [FAR]

[FourGreenFields]

CrisK Bird of Prey

I tweaked this fellow a lot this morning. It's now highly maneuverable sub-sonic. AOA of 25*. Capable of vertical climb. Now stable while supercruising. Highly stable sub-sonic. No yaw problems (unless fully stalled, but that's not possible while the afterburner is on). It's actually a really decent fighter. Its numbers are similar to the real-world F-16, which I would have thought impossible given the limited yaw stability. It makes me wonder what would have happened if the Navy had commissioned Boeing's Bird of Prey instead of turning it into the unmanned X-45.

How did you prevent yawing when using ailerons? Countered with brake rudders? Only added ailerons to the anhedral part of the wing? Some mod that allows for a proper yaw staibility assist?

Also, did B9PW update yet? Dev version? Old version still working?

[Van Disaster]

Old version still working. Crzyrndm linked one compiled against 1.0.5.

[CrisK]

How did you prevent yawing when using ailerons? Countered with brake rudders? Only added ailerons to the anhedral part of the wing? Some mod that allows for a proper yaw staibility assist?

Also, did B9PW update yet? Dev version? Old version still working?

To be honest, it was just a matter of playing around with wing shapes and sizes until I found something that was stable. If I make the wings any larger the design no longer works. This is the first time I've designed something with this type of wing.

It does not work with mods that assist yaw stability. Something about having an inverted yaw control surface seems to throw Pilot Assistant off; it does not work with this plane.

Van answered before I could. Here's a link to Crzyrndm's github.

[Halsfury]

Honestly it is frustrating that the centre of lift indicator isn't working, I wouldn't care if I were building straight wing aircraft but it's quite a struggle to get the CoL working right, and then to figure out how to tweak things so that they're just where you want them

On that note I updated the Su-27, it's finally working again.

the F-16C is now super maneuverable thanks to 15 degree thrust vectoring, and the F-18 is as far as I can see the same as ever

[Van Disaster]

Well the CoL ball *never* worked completely - I've had craft with it in front of the CoM ball which were green across the board at any speed for static derivatives - after multiple reloads/edits.

I'm sure there's a dance to get it settled rather than in the nose, but I've not worked it out yet.

[FourGreenFields]

Seems promising. Reaches nearly Mach 1.9 at 10km without afterburner, which I suppose isn't bad (but can't really judge because it's the first top speed I've tested with the new engine).

Problems are that it needs the cockpit reaction wheels to roll at 0 speed, and that it can't pull much without the engine. Pretty sure the latter is fixable though.

On a related note: Does BD armoury also work with 1.05?

Edited November 13, 2015 by FourGreenFields

[Hodo]

http://i.imgur.com/wa74XKC.jpg

Seems promising. Reaches nearly Mach 1.9 at 10km without afterburner, which I suppose isn't bad (but can't really judge because it's the first top speed I've tested with the new engine).

Problems are that it needs the cockpit reaction wheels to roll at 0 speed, and that it can't pull much without the engine. Pretty sure the latter is fixable though.

On a related note: Does BD armoury also work with 1.05?

I haven't tried 1.0.5 yet, so no clue if BDArmory works. I refuse to install it until everything I run is updated. I am patient like that.

But very 1950s sci-fi of your design there.

[Van Disaster]

I've tried the radar, vulcans & Sidewinders in 1.0.5, they all seem to work ( even with the heating change ).

[tetryds]

Try out the E42, packed with the latest version of FAR.

I call it an hypermaneuverable fighter, because it can pull some insane stunts.

During supersonic flight press 2 to turn off gimbal, if you do that you can pilot normally.

[Doke]

A teaser from my current WIP prototype family.

Stats vary as I tinker with it, but expect a cruise speed of Mach 2, sustained AoA of 30-50 degrees without thrust vectoring or 180 degrees with, and a spacious weapons bay for all your explosive needs.

The biggest challenge is blending the canard/levcon section into the wing in a way that is stable, structurally sound and properly area-ruled. The original version used a structural chine that mirrored the wing angle (stealth!) and an all-moving wingtip thingy, and it was absolutely brilliant except for the horrific tip stalls causing total loss of control (which I guess is why nobody uses anything like that in real life).

I like the tailsitter, by the way. What are landings like?

[FourGreenFields]

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Wasn't initially intendet as VTOL, but turns out that new jet engine can make pretty much anything supermanoeuverable.

Will need to redo for radar etc though

EDIT: Seems I got ninja'd.

Calling it "the tailsitter" won't work though, because I allready built several designs which can land and take off like that.

Landings - just landing anywhere is pretty easy. Fly slow enough for supermanoeuverability, point nose back to slow down, descent killing all non-vertical velocity, then slow down to about 3m/s just before touchdown. And make sure that the thrust to weight ratio is below 1 at touchdown.

Landing on a small spot is tricky, because any kind of horizontal velocity will flip the thing during touchdown. Can also take a while to reach that spot. But if you're carefull, it's not too difficult.

Edited November 13, 2015 by FourGreenFields

[Van Disaster]

@FGF: I tried the vector engine on one of my AI craft, and it spent quite some time sitting stationary at about 2000m doing nothing except slowly rotate...

AI & vectoring is not a good combo *at all*.

[Doke]

@FGF

It's so cute!

@Van Disaster

Does altering the gimbal range help? I'm also wondering whether being stationary is necessarily a bad thing if it lets you get a missile off, then go into pursuit. I have a feeling that vectoring has the potential to really shake up the AI contests; I'm betting we'll see some strange designs.

I made a clean install for 1.05 and I'm only running FAR at present, but I'll give BD a try soonish.

Congrats on your win, by the way.

[tetryds]

Landing on tail is not hard at all:

*Older version of the E42*

Here is it's top speed bellow 200m no afterburner:

With afterburner it goes up to Mach 2.45.

[Van Disaster]

@Van Disaster

Does altering the gimbal range help? I'm also wondering whether being stationary is necessarily a bad thing if it lets you get a missile off, then go into pursuit. I have a feeling that vectoring has the potential to really shake up the AI contests; I'm betting we'll see some strange designs.

What usually happens is the AI pulls the thing into a stall, and then doesn't unstall; the opponent flies rings around it and eventually makes use of the fact that it's near stationary & guns it to pieces. If you adjust the gimbal range until it works then it's not supermanoeverable anymore, and you can do just as well with a lighter engine & good aerodynamics. Also the vectoring is either all or nothing, there's no adjustment tools like a control surface ( exposing gimballing as control surfaces would be a pretty nice mod, tbh ).

The last couple of craft I did for the other challenge could pull 38deg AoA constant & 42ish transient without stalling, with standard engines. That was pushing it somewhat because that sort of AoA saps energy like crazy.

Waiting on a few more mod updates & then I'll attempt something for this challenge ( although without AJE, I guess ). I still go fly my 0.90 Retrofuture creations a fair bit, I miss the stuff from that install that's never been updated.

Edited November 13, 2015 by Van Disaster

[Doke]

@tetryds

I salute that landing. Show off!

@Van Disaster

That's a shame. Won't stop me from trying, though

Hopefully mod updates will remedy things.

[TheHengeProphet]

What usually happens is the AI pulls the thing into a stall, and then doesn't unstall; the opponent flies rings around it and eventually makes use of the fact that it's near stationary & guns it to pieces. If you adjust the gimbal range until it works then it's not supermanoeverable anymore, and you can do just as well with a lighter engine & good aerodynamics. Also the vectoring is either all or nothing, there's no adjustment tools like a control surface ( exposing gimballing as control surfaces would be a pretty nice mod, tbh ).

The last couple of craft I did for the other challenge could pull 38deg AoA constant & 42ish transient without stalling, with standard engines. That was pushing it somewhat because that sort of AoA saps energy like crazy.

Waiting on a few more mod updates & then I'll attempt something for this challenge ( although without AJE, I guess ). I still go fly my 0.90 Retrofuture creations a fair bit, I miss the stuff from that install that's never been updated.

This is precisely why I asked BahamutoD for a minimum speed setting.

It would be wonderful if there was something which allowed specific control settings for gimbal, because I very much need to disable yaw in order to make the Spite even usable with gimbal enabled.

On the bright side, the spite is much lighter now due to the lighter engine, weighing in at 8.6t! Its sister plane now weighs as much as the old Spite at 9.2t and can sustain much higher G loads. Still needing to determine which is actually better, because I'm not sure the AI even really understands at this point.

[Halsfury]

Also the new engine cuts out at very high altitude especially when after burning (25km while after burning). The lighter tail has a tendency to cause nose heaviness leading to poor turning in some old designs like my Su-27

I fixed it by removing some unnecessary strakes which were doing a lot of harm to the overall aerodynamics, it's amazing to thing that only 8 inches of extra wing were spoiling the whole plane, I'll post it soon

EDIT: Also the new engine is very efficient for our purposes so ranges have been much improved

EDIT 2: AH HA! try using the FAR analysis page in the SPH to raise then lower the landing gear to get the CoL to work properly, while doing this press the "Calculate stability derivatives" button when you raise the gear and then press that button again when you lower them.

Please let me know if it works

Edited November 14, 2015 by Halsfury

[FourGreenFields]

Assuming the 10 ton min weight rule stays: 10 tons in the hangar, or 10 tons when checking using map view?

Just got a plane to 10.0 tons with drop tank and missiles, but map view shows 9.24 tons. Do I need to increase the weight some more?

[TheHengeProphet]

I'm going to take rule 9 very literally:

• The aircraft must not weigh less than 10 tons at takeoff with a full combat load.

So long as you load it up with enough munitions to weigh 10t and still be able to take off and fight with it, it should be fine. I still don't exactly approve of the rule, hence why I built the spite in the first place.

[edit] I may well be running into glitches as far as the afterburner goes, but it's practically impossible to tell considering air is no longer a visible resource... Starting at low altitude and staying at low altitude, the afterburner works fine, but if I go to high altitude where the engine starts to lose power from lack of air, if I switch to afterburner I actually lose thrust, and this loss of thrust seems permanent, considering I dropped back down to near sea level and was not able to return proper functionality to the engine. Anybody else able to replicate this? I want to make sure this is actually not just happening to me before I try to report it.

Edited November 14, 2015 by TheHengeProphet

[Doke]

AH HA! try using the FAR analysis page in the SPH to raise then lower the landing gear to get the CoL to work properly, while doing this press the "Calculate stability derivatives" button when you raise the gear and then press that button again when you lower them.

Please let me know if it works

I tried to replicate this, but unfortunately (?) I can no longer replicate the bug with the new version of FAR.

Regarding vectoring: more control over axes would certainly be welcome, as would some way to apply dynamic deflection to them, but part of the problem seems to be an extension of the tendency of stability controls/BD AI to get itself into nasty oscillating situations with overcorrection. I'm not sure what, if anything, can be done about that.

I wouldn't completely write off vectoring, though. Aside from the ability to pull off cool stunts (I spent quite some time last night pulling 360 degree flips in both yaw and pitch axes for giggles -- quite a lot of fun while low over the KSC in IVA mode), it really helps in situations where control authority might otherwise be weak. The poor Skua has taken quite a beating with the recent patches; the relative centre of lift has moved back a lot (or the centre of pressure has moved... Forwards? Is that how it works?) -- in any case, pitch authority is now dismal. Fixing it seems to require a complete redesign of the planform, and my efforts in that direction quickly ran into new problems, so I would essentially be designing a new plane.

However: with thrust vectoring, the Skua is able to regain some of its former glory. I ran a few test fights, Skua versus its replacement ('Cormorant'), and while the Cormorant completely destroys the Skua if neither have vectoring, a Skua with TV has enough energy retention (and otherwise undesirable stability) that it can still spring nasty surprises on more agile planes (though it does wobble like a top in the process).

EDIT: I tried to replicate the problem TheHengeProphet had, but no luck.

Edited November 16, 2015 by Doke

[TheHengeProphet]

I have been having trouble replicating it myself. Thanks for trying! This is clearly an odd glitch, so I'll have to figure out exact repro steps.

Also, the latest FAR ("Helmholtz") seems to have resolved the CoL marker issue. I'm back to developing the Spite and its unnamed sister plane into worthy death machines. The thrust vectoring really adds a whole element I never really considered in the original design, so the previously "unstallable" planes will now do so... It's not hard to adjust their AoA values higher, but then they don't change vector as well. Edited November 16, 2015 by TheHengeProphet

[Doke]

Yeah, I'm starting to think less in terms of maximising AoA and more in terms of AoA versus energy retention. 'Post-stall maneuverability', as I believe the Russians are calling it, seems like it would always be a desirable quality, though. Incidentally, I saw Bahamut demoing some fights on Twitch last night, and I swear at least one of them had craft using thrust vectoring with no discernable wobble.

BTW: any tips for increasing a craft's aspect ratio? I suppose I could make it spout narrow flaps sideways. The Cormorant has plenty of lift area, but the aspect is so low that landing is quite tricky. Not impossible by any means, but it likes to come in fast.

[edit] To clarify, I mean [I]temporarily[/I] increase aspect ratio. Edited November 16, 2015 by Doke

[Van Disaster]

Deltas should be able to pull such vast AoA that landing slowly is doable ( probably safer than a more conventional craft, even ). Just keep pulling the nose up until you're increasing thrust again, and you have braking on demand. You could try Q-dependent wing shaping with surfaces like I mentioned a while back, but that's a bit much for just landing.

Stalling is a huge energy sink, whether you keep control or not. Highly swept wings don't really stall the same way as straight ones but even vortex lift runs out eventually, and vortex lift itself is not low-drag...

[Robet.G]

The rules reads like this to me:
"must look exactly like an F-16 or it doesn't count"