FAR Fighter Challenge: BD Armory AI

[Magnavox]

I'm hoping I can get some advice for making this design more competitive. I have some experience building SSTO's under FAR but I'm finding while there are a number of tutorials for beginners using FAR, not so many for advanced users.

https://drive.google.com/open?id=0B13Bfbd-pPp0Z2xOcVZ6ME5kU0U

This is my Super Dart. The problem is that it stalls in the first turn after takeoff. I'm not sure how to improve it's stall characteristics. I think I have something here. but Not sure what to change to improve it.

[SpaceplaneAddict]

If your using Dynamic Deflection, I can REALLY give some help.

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Ahh, I see the problem. You have to much control authority at low pressure. Within DD, for most fighters, you would want just a little bit of authority, enough for basic maneuvers. Then, at higher pressures(40-50Kpa) you want maximum authority, cause at high velocities, an aircraft tends to keep a stable AoA.

[Magnavox]

OK, so I solved the stalling issue by abandoning canards and going to all moving horizontal stabilizers at the rear. It actually won a fight against the K-14 for the first time ever.

https://drive.google.com/open?id=0B13Bfbd-pPp0ejIwZFNFZXBuSFE

Is there some simple trick I'm missing for reducing over control leading to oscillation? This plane flies, but it's all over the sky doing it. I'd be interested in some advice since I have this problem with my SSTO's as well.

[SpaceplaneAddict]

It's the K-35 BTW.

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Less roll/yaw authority.

[Wanderfound]

This is my Super Dart. The problem is that it stalls in the first turn after takeoff. I'm not sure how to improve it's stall characteristics. I think I have something here. but Not sure what to change to improve it.

To reduce stalling at all speeds:

* Move lifting surfaces towards the rear.

* Add AoA settings (negative AoA on leading edges and canards, positive AoA on elevators) to pitch-relevant control surfaces (if they are stalling) and/or add leading edge slats (if the main wing is stalling). Right-clicking lifting surfaces during flight will tell you which ones are stalling or not.

To reduce stalling at particular speeds:

* Alter the DD settings (hover your mouse over the relevant control surface, hit "k") to reduce control authority at the pressures at which stalling occurs. The FAR in-flight data screen can provide pressure info while test flying.

[SpaceplaneAddict]

So uh, wanderfound, how you like my K-35?

[Wanderfound]

I'm surprised that a semi-realistic plane was able to compete with the shingo. I think that a large delta wing design is the best way to go if you're building an AI drone.

From the video we can see that missiles are functionally useless on any plane that can fly faster than Mach 0.5 and make reasonably good turns. The best way to optimize for the AI is to create a very pitch-stable design so that there are opportunities for the AI to use the gun.

[SpaceplaneAddict]

Finally, a new champ. K-35 now?

EDIT: sorry if I'm impatient. I just put a lot of hard work on it, and want to see it fly officially

[Doke]

Anybody hating my K-35 yet?

I don't hate it, but it is quite impressive.

OK, so I solved the stalling issue by abandoning canards and going to all moving horizontal stabilizers at the rear. It actually won a fight against the K-14 for the first time ever.

https://drive.google.com/open?id=0B13Bfbd-pPp0ejIwZFNFZXBuSFE

Is there some simple trick I'm missing for reducing over control leading to oscillation? This plane flies, but it's all over the sky doing it. I'd be interested in some advice since I have this problem with my SSTO's as well.

If you're talking about the way the plane 'fishtails' under AI control, you might try tinkering with the deflection settings or increasing control damping under AI settings. Basically, though, I've found it insoluble. Most planes seem to suffer from the same problem to a greater or lesser extent -- if there's any kind of instability, the AI often overcorrects.

That's a really nice little plane, btw. I wonder whether the lack of radar and long-range engagement options might be hurting it, though (not that I'd know where to put them).

EDIT: re: missiles, they're definitely not useless, as you can see from the Arctic Skua's fights, but there does seem to be a very small chance of actually scoring a hit, though.

Edited September 27, 2015 by Doke

[Magnavox]

@Doke: Thanks. I was going for a flying wing motif which has sort of leaked away in the face of control issues. It does have a radar; inline behind the intake. But I added it only so the AI can see it's target beyond 3.5km. I messed with the AIM-120's but they are considerably shorter legged than their real world 50km or so range. I was going for a gunfighter anyway for the above mentioned missile problems.

https://drive.google.com/open?id=0B13Bfbd-pPp0cFJ3ZkFJSy0wLVU

Here's the block 6 version. I've got most of the control issues ironed out, now the plane just breaks in half under high G turns. Though it did get some spectacular kills against the K-35 and many many more spectacular deaths. I've discovered that it will at least fly more or less straight missing one wing.

Wanderfound. I've noticed that everyone's planes fly much more smoothly in your vids than they do on my system. Is this a universal setting change or an effect of your rendering?

Edited September 27, 2015 by Magnavox

[Wanderfound]

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Wanderfound. I've noticed that everyone's planes fly much more smoothly in your vids than they do on my system. Is this a universal setting change or an effect of your rendering?

Tried flying them in an install with BD Armory, FAR, Dynamic Deflection and no other mods? All three mods are vital; leaving out any of them will radically change things. Avoid any other performance-altering mods like Stock Bug Fix.

The vids are sped up to 250% original, but apart from that they're unaltered.

[Magnavox]

I thank you all for your good advice and assistance in helping me understand the finer points of Kerbal aerodynamics. So gentlepersons of all genders, I would like to announce my entry into the contest. After the troubles I had with my Turbo Slaber and Super dart I sent my engineers back to the drawing board. After I told them that they couldn't use crayons on it, they came up with the Faukker DR-3.

https://drive.google.com/open?id=0B13Bfbd-pPp0RkpVVjZWX3lZa00

Edited September 27, 2015 by Magnavox
Updated for the correct craft file.

[Van Disaster]

Any tips on stopping the AI pulling too hard? doesn't seem to handle supermaneuverable planes too well, although at least it doesn't crash them much...

[SpaceplaneAddict]

Increase steer dampening, and sometimes, decrease steer factor.

[Van Disaster]

Steer damping is maxed - problem is it'll pull until it stalls, and then fly in small circles at 30m/s. Only way to get it to keep speed up is to turn the steer factor down to about 2, and then it wants to fly over the horizon . Ideally I'd like to link steer factor to airspeed...

[Wanderfound]

Steer damping is maxed - problem is it'll pull until it stalls, and then fly in small circles at 30m/s. Only way to get it to keep speed up is to turn the steer factor down to about 2, and then it wants to fly over the horizon . Ideally I'd like to link steer factor to airspeed...

...which is where Dynamic Deflection comes in. Airspeed correlates (imperfectly, but close enough) with air pressure. Tweak the DD settings to reduce control authority at low pressure.

Mouse over the control surface and hit "k" to raise the menu. It'll require fine tuning for your particular ship, but I usually start by setting authority to 20% at 0kPa and raising it in a curve towards 100%/40kPa. Take it up, test-fly it, note the pressure if it starts overcontrolling, then go back and shave some more authority from that pressure. Aim to keep the plane just short of stalling out.

[SpaceplaneAddict]

Have you messed with Dynamic Deflection yet? Ideally, you would want low deflection at low pressure, and lot's of deflection at high pressure. If you post a .craft, I could try to help further as well.

Edit: Ninja'd.

[Wanderfound]

[Magnavox]

Wanderfound. What HUD are you using that gives you the stall warning and Q factor. I've seen in it your other vids and always meant to ask.

[Doke]

That was sufficiently exiting.

[SpaceplaneAddict]

Well that didn't look like a dogfight at the end

[Wanderfound]

Wanderfound. What HUD are you using that gives you the stall warning and Q factor. I've seen in it your other vids and always meant to ask.

Kerbal Flight Data​.

[Doke]

Well that didn't look like a dogfight at the end

The AI is quite impressive, but I've noticed that it really needs at least a manual setting for 'corner speed' or something like that. The K-35 only needed to pop its airbrakes and pull a hard turn to evade, but the AI doesn't seem to understand that it should slow down to increase turning. I've had the same thing happen in reverse; sometimes the K-3 AI opens its brakes and tries to get into a scissors when all I want it to do is put the nose down and go supersonic.

[SpaceplaneAddict]

.

I didn't add airbrakes.

Reasons is, the K-35 pulls with such an AoA, it bleeds speed naturally. Never thought the AI would be dumb enough to NOT turn in a dogfight.

Oh well, next iteration, the K-35B will probably have more fine-tuned handling and, yes, A.I.R.B.R.A.K.E.S.

[Doke]

In that case, I have no idea what it was trying to do. The AI does seem to be weakest on the defensive (though it sometimes pulls off a nice scissors).