The 5th Generation Fighter challenge [FAR]

[FourGreenFields]

I had no idea! Thanks for this. It's going to make using the editor a much more pleasant experience in the future. I just gave it a quick try, and it didn't seem to help my landing much, though. I thought it might try lowering the plane's attitude on the ground, but that didn't help either. I'll need to give it another try later when I have time.

Does that also happen when taxiing on the ground at high speed? Throttle up on the runway, and accelerate beyond landing speed without taking off, possibly with landing flaps, and any spoilers you have activated during touchdown. If you lose control doing that, the problem is indeed the landing gear.

If that isn't the problem, use brakes. If they cause instability, strut the gear legs and/or reduce brake torque. Possibly pull on the elevator while below takeoff speed (I found that it usually helps a bit - I think it's because it reduces the load on the front gear leg(s)).

If neither causes problems, it's prob how you touch down.

Brakes disabled as you touch down, little to no vertical velocity, no side slip, no roll angle. If you do that, a plane with properly working landing gear should land fine.

[Doke]

Thanks for the tips. I'll give it a try later.

EDIT: It turns out the problem was much more simple. The asymmetric cannon and electronics arrangement was causing problems. Fixing that makes it landable (and means I have to tweak a bunch of other stuff, but the problem is solved in principle).

Edited September 18, 2015 by Doke

[TheHengeProphet]

@CrisK That sounds like fun. Let me know where you're streaming!

I'll see if I can't look into Doke's landing gear issue when I get a chance.

Edit: Tested out Dynamic Deflection, and under consideration have determined I will not use it. This is due to it being a broad sweep across all planes, disallowing for a per-plane profile setup.

Edited September 19, 2015 by TheHengeProphet

[Doke]

@TheHengeProphet thanks for the offer of help, but I think I've got it figured out and wouldn't want you to waste your time. Also, I didn't realise DD uses a single profile for all planes. It saves settings in the craft file, so I had assumed they were unique.

[SpaceplaneAddict]

So no Dynam Deflect? Ok.

- - - Updated - - -

I'll still use it though, 'Cause I want to.

[TheHengeProphet]

Hey, I'm not saying other people shouldn't use it. It's a decent tool. I just don't like it.

@Doke already been messing around with it, and even tried replacing the landing gear with adjustable ones. Best I can tell, it's involved with gear orientation, though stock landing gear is a bit stiff, and the front gear being so tall was not helping. No matter what I do, though, the plane seems to veer to the right on the runway, so that's interesting. Those fins you've porcupined your plane with are actually doing a world of good and haven't managed to do better than what you've got, but replacing the landing gear did actually improve your aerodynamics, though judging from the construction of your plane, I wouldn't expect you to use part mods, haha. This thing really is kind of a marvel to me, nice job.

Trying to improve things is a hobby of mine, so I never really consider it a waste of time. I'm just hoping my constant quest for perfection doesn't offend anybody, heh.

Ergh, going to continue trying DD, because I guess it DOES have control variability per plane, but the default is not 0 adjustment... That's a massive faux pas, to me, though.

Edited September 19, 2015 by TheHengeProphet

[CrisK]

@CrisK That sounds like fun. Let me know where you're streaming!

I'll see if I can't look into Doke's landing gear issue when I get a chance.

Edit: Tested out Dynamic Deflection, and under consideration have determined I will not use it. This is due to it being a broad sweep across all planes, disallowing for a per-plane profile setup.

Henge, I think that you were using it wrong. Every single control surface has its own setup. You can copy your setup across an entire plane, but that's sub-optimal.

PS: Doke, disable the brake torque on your forward landing gear. Attach your rear gear to one of the central shaft tanks, then use the offset tool to place it. These fixes solve the problem.

[TheHengeProphet]

Henge, I think that you were using it wrong. Every single control surface has its own setup. You can copy your setup across an entire plane, but that's sub-optimal.

Yeah, I got that. I've been messing around with it and finding it remarkably frustrating. This is largely due to it preventing further adjustment to the control value of a surface in flight outside of its own contextual windows, meaning I cannot further increase control values for tuning. This means the only reasonable way to adjust values is to set the control surfaces to the maximum and deny control from there, which is terribly frustrating.

[SpaceplaneAddict]

You can go up to 225% on conventional control surfaces. Full 89Degrees compared to FAR's 40Degrees

Edit: read your post wrong. While(yes) it is frustrating, I find trial and error ti be ine of the best ways to test things

Edited September 19, 2015 by SpaceplaneAddict

[Doke]

@Henge That's very kind of you. The plane is as much accident as design. Having used only stock, yeah, I guess I'd rather get the crappy stock landing gear if I can. Plus, it would probably mess up my area-ruling if I changed them. Regarding tinkering: knock yourself out. It's always interesting to see the way other people design things.

@Crisk That's awesome, thanks! I'll give it a try.

Regarding DD: agreed that it can be a bit fiddly. That said, I don't think it's as useful if you're flying the plane yourself with an analogue controller. In my case, I set it up so that the AI would have a chance in the dogfighting contest.

[FourGreenFields]

A little something I've been working on (just to experiment a bit before 1.1 hits).

My try at the lightest possible fighter/interceptor; Low wing loading; 2 20mm gatling cannons, one ammo box; 6 rocket rails planned, but 2 of them intendet for use with droptanks;

Critical AoA seems to be somewhere between 50° and 55°. I wouldn't want to land like that though.

As you can't see it that good on the screenshot (and too late to make more now) a short description:

Intake; Cockpit; RADAR; Jet engine.

Wings are slightly swept and relatively thick - all fuel stored in the wings. Leading edge is extended near the root; The leading edge is also triangular instead of biconvex there.

Trailing edge works as elevator and ailerons.

[CrisK]

I created a version of the S-USAF that uses dynamic deflection. It's now supermaneuverable at any speed up to Mach 1.? (I'm not sure what the upper end is) while fully armed with 4 sidewinders and 4 AMRAAMs. Its upper limit seems to be 21G turns while fully armed. I had to add two struts to achieve this, but I was able to remove two parts elsewhere to balance it out.

I also disabled torque on the cockpit and drone core (Henge's version reminded me to do that). It actually flies better without the phantom torque. The drone core lets it fly as a BDArmory drone, and it also acts as an internal battery since the MK2 core includes 250 electrical charge. Regular batteries often inexplicably overheat and explode when in the air.

Javascript is disabled. View full album

Edited September 21, 2015 by CrisK

[TheHengeProphet]

@FourGreenFields 50°+ critical AoA? That's crazy good. I'd be really interested in seeing this thing in more detail. What's it weigh even? 5t?

@CrisK Looking good! I'll have to set some more time aside to try it out. Yeah, batteries behave oddly, but I'm hoping that'll get fixed in the next version.

[FourGreenFields]

@FourGreenFields 50°+ critical AoA? That's crazy good.

Crazy good of an airbake, yes. Way too much drag to be worth building it that way. It just ended up being able to pull that much.

Also, at insane AoAs you're going to have a hard time rolling without some kind of yaw assist (and I don't think the stuff we have ingame helps much here).

Anyway. Map view shows 6.2 tons wet (with ammo, countermeasures, flares, chaff; No external stores, no monoprop), 4.98 tons empty weight. May be able to slightly reduce that when tweaking wing mass (or it may increase - we'll see).

Way too heavy imo, but just intake, cockpit, RADAR and engine weigh 3.19 tons allready. I really hope the new jet engine is lighter.

As I can't seem to be able to change album settings, image descriptions, etc. (I blame my network - Data volume -> 5kB/s) I'll just post the album now, without having edited it:

Javascript is disabled. View full album

EDIT: Ok, managed to change the settings now. Had to go to "browse images" first for whatever reason.

EDIT2: For whatever reason the images aren't rearanged here... but on imgur they are... whatever. I'll try removing the album, then adding it back in.

EDIT3: And that didn't work. Whatever.

EDIT4: And it works now. Reasons.

Edited September 23, 2015 by FourGreenFields

[TheHengeProphet]

@FourGreenFields 6.2t is pretty light, but that's only 3t lighter than the Spite, for a lot less body... I'm curious, though: if you split the rear control surfaces into ailerons and elevators, of approximately equal size, when you pitch, do you get very strange behaviour, like kicking to one side when in hard pitch? It's a problem I've been having and I'm wondering if it's capable of replication...

@CrisK I tested out your latest iteration (Mk3) and found it quite easy to fly, like all of the other versions, and yet I was unable to get it to pull a consistent 6g at altitude at half thrust. It would peak there beyond that, but wouldn't pull it consistently. It does handle decently well at all altitudes, though, which is useful. That's a decent payload you have on there, and I'm sure it could hold more and still work fine.

[FourGreenFields]

@FourGreenFields 6.2t is pretty light, but that's only 3t lighter than the Spite, for a lot less body... I'm curious, though: if you split the rear control surfaces into ailerons and elevators, of approximately equal size, when you pitch, do you get very strange behaviour, like kicking to one side when in hard pitch? It's a problem I've been having and I'm wondering if it's capable of replication...

Kicking to one side = Yawing?

If so, my guess would be that you're using ailerons. Rolling basicly turns your AoA insto your slip angle. Also, ailerons usually produce a minor yawing movement in the opposite roll direction. Would definitly mess things up.

I think I'll try it anyway though. Soonâ„¢

[FourGreenFields]

Ok, tested now (but with about 1/3 ailerons, 2/3 elevator). I do feel like that change increased the yawing movement when rolling at low speeds. No warranty though. And can't really explain why it'd be like that.

[Doke]

I'm really liking the look of some of these planes (Falconet, USAF, etc.), but I'm not sure which mods I need to fly them. Also, the Falconet looks like it would make a fantastic drone -- I can see them as a fun little swarm of expendable fighters.

I've done some tweaking of the Skua and it can actually be landed now (not sure about the old strip). Waiting for 1.1 to hit before I finalise it though. I have a horrible feeling the new engines are going to mess everything up.

[TheHengeProphet]

Ok, tested now (but with about 1/3 ailerons, 2/3 elevator). I do feel like that change increased the yawing movement when rolling at low speeds. No warranty though. And can't really explain why it'd be like that.

The rapid "kick" I experience is a hard yaw to the left or right when pitching hard under almost any circumstance. Not sure if I should bug ferram4 about it or just wait for the next release, which has a wing overhaul and see if it still happens...

@Doke For most of the planes, you'll probably need B9 Pwings and Adjustable Landing Gear on top of BDA. For my Spite and Spectre, you will also need QuizTech Aerospace. I'll work on uploading versions of my planes designed to ignore Dynamic Deflection until I can either tune them to work better with it or just stop caring. But that'll likely happen tomorrow.

[FourGreenFields]

The rapid "kick" I experience is a hard yaw to the left or right when pitching hard under almost any circumstance. Not sure if I should bug ferram4 about it or just wait for the next release, which has a wing overhaul and see if it still happens...

Haven't seen that happen.

Anyway. Insanity ftw!

Javascript is disabled. View full album

Tbh though, it's not really insane. But it looks like it shouldn't really be flying imo.

Will need to tweak this thing to not roll when pitching, but once I've done that, it should be fine.

Also currently no ammo stored and haven't been able to test maneuverability due to abovementioned rolling movement, so I may need to reposition/redesign the wings. I just hope I'll be able to keep the wave drag area below 0.09m²

[SpaceplaneAddict]

My K-35 might be my best bet. It has a TWR of THREE according to mechjeb.

[TheHengeProphet]

@ThreeGreenFields Oblique wing designs have that problem, to my knowledge. Not really sure how to solve it either.

@SpaceplaneAddict That's impressive. Does mechjeb take thrust limiters into account when measuring T:W?

[SpaceplaneAddict]

Ye, but the TWR was 3 at 100 percent.

It's 1.5 at 50.

[CrisK]

A TWR of 1.5 is very high. Most fighter jets are in the 1.0 to 1.1 range. The space shuttle was 1.5.

There's no tangible benefit to having a TWR above around 1.2. Even the F22 can only reach 1.26 with 50% of its fuel drained.

[FourGreenFields]

@ThreeGreenFields Oblique wing designs have that problem, to my knowledge. Not really sure how to solve it either.

I'll make the wings asymmetric in span (iIrc left wing needs to be slightly bigger than right one in this case), and may help counter that effect using one or both ailerons (possibly need to download DD for that).

Also, allthough the shamrock is three-leaved, Ireland has 4 provinces, and they are what the song Four Green Fields is about.

A TWR of 1.5 is very high. Most fighter jets are in the 1.0 to 1.1 range. The space shuttle was 1.5.

There's no tangible benefit to having a TWR above around 1.2. Even the F22 can only reach 1.26 with 50% of its fuel drained.

Climb rate > anything else. (imo)

Ok, for KSP 5. Gen fighters maybe service ceiling plays an importand role too, as you climb to that alt relatively quick. But climbing enables you to disengage, or dive back on your opponent at will.

Running and diving only help to disengage (or at least it's difficult to reengage while ensuring you're on the offensive).

Turning is limited mostly by the pilot's ability to sustain G-forces at high speed, so the plane plays less of a role here (not to mention that an opponent with better climbrate can simply pull up and go in the vertical). And at low speed you lost all initiative and are a sitting duck anyway.

Also, climb rate helps intercept enemies, if you have little time to climb. And with a good TWR you generally also need shorter runways for takeoff.

Climbrate > Speed and Dive speed >> Turn time.

TLDR: I'll never get why there are people out there who like the Spitfire better than 109s (past the F-4 at least, and may need to leave the griffon spits out of that).

Edited September 26, 2015 by FourGreenFields