The 5th Generation Fighter challenge [FAR]

[CrisK]

The flying wing design is pretty cool. I would not have thought of it.

[FourGreenFields]

And the P 18 "Firecrown" is finished.

Javascript is disabled. View full album

46.1 points. Basic jet, BD Armoury.

Capable of VTOL with full fuel load (400 litres) and 2 sidewinder missiles. Insane roll rate at high speeds. The sidewinders don't have any noteworthy influence on speed. 2 counter measure pods. Also capable of VL without any fuel.

Not capable of a normal landing, or normal takeoff without a special dropable undercarriage.

EDIT: And being inspired by the "Natter", it is meant as light-weight, high-speed interceptor, so the turn rate is acceptable.

EDIT2: Craft file on KerbalX

EDIT3: Btw: Can already pull 10 Gs at about Mach 1.2, so the turn rate isn't quite as bad as the screenshot makes it seem.

Edited July 31, 2015 by FourGreenFields

[RocketTurtle]

And the P 18 "Firecrown" is finished.

http://imgur.com/a/RbOus

46.1 points. Basic jet, BD Armoury.

Capable of VTOL with full fuel load (400 litres) and 2 sidewinder missiles. Insane roll rate at high speeds. The sidewinders don't have any noteworthy influence on speed. 2 counter measure pods. Also capable of VL without any fuel.

Not capable of a normal landing, or normal takeoff without a special dropable undercarriage.

EDIT: And being inspired by the "Natter", it is meant as light-weight, high-speed interceptor, so the turn rate is acceptable.

EDIT2: Craft file on KerbalX

EDIT3: Btw: Can already pull 10 Gs at about Mach 1.2, so the turn rate isn't quite as bad as the screenshot makes it seem.

Yeah my planes disassemble when pulling any Gs at at any mach, so I'll give you that.

[Gnullbegg]

Allright, so when I stumbled upon this challenge a few days ago, it really made me want to try out FAR for the first time ever, and I've been having a great time! Thank you so much! What this also means is that I'm a total newb with this mod. To be perfectly honest I kind of still am one with KSP aircraft building in general, so pls be gentle.

I had been tinkering around with a new jet in stock which looked promising, in fact I should say it was my new favourite original plane design and for something I made, it's been flying quite well with the new stock model. 5 seconds after maiden take-off in FAR, however, guess what happened (exactly, it exploded). A good laugh, some flights with way better planes from other people and about a dozen (ok more, many more) revisions later, I *think* I met all the criteria, except maybe one (TWR, see pics).

Here goes:

Javascript is disabled. View full album

I won't bother counting score at this point as I'm not even sure if I did things right with this challenge. And there are of course many many problems with this design and I'll gladly appreciate any help from people with actual experience with FAR or aerodynamics in general to improve on it. Some of the more pressing ones are, roughly in order of importance:

• Transsonic design. Wave drag area is 1.07, which I have managed to bring down from 1.38 by doing the ape-on-a-typewriter dance with the offset tool but I will *not* pretend that I had *any* idea what I was doing. I just watched that one vid from earlier in this thread and then fiddled around trying to make the number go down. I *think* the undercarriage has the most potential for optimization, but I honestly have no idea how to get it below 1, let alone into the regions some of you have achieved (which I'm totally aware won't be possible with this design)
  
• Rudder settings, or actually control surface settings in general. Yaw is the biggest one though. I've already set it down to 5, but I still get the feeling that it might be too sensitive as the plane is hugely sensitive to combined yaw-roll maneuvers of any kind and will very quickly go into a spin. Pitching up also leads to minor stalling quite often, but that may be normal? I don't know
  
• General stability issues above mach 2. The thing likes to deviate to all kinds of sides and generally wobbles around quite a bit. Might be connected to my first problem, might even be somewhat inevitable with how the wings are shaped and placed?
  
• Structural integrity. The nose likes to come off first. After that it's the main wings. The tailsection is apparently made of hardened unobtainium and almost never breaks. I know I could up the strength of the parts but that would then again ruin the TWR and probably the COM as well. Maybe there are some magic tricks that I'm not aware of? This is probably least important because I get that everything breaks at some point. It would be nice if the plane could withstand a little more though.
  

Here's the .craft-files:

1. https://www.dropbox.com/s/ljj0ndw71c96axg/GAD%20X21-3%20Nightjar%20%28transsonicpls%29.craft?dl=0 This is the most current version, the one I did try the challenge with
   
2. https://www.dropbox.com/s/o7ewojfy3skl7vx/GAD%20X21-2%20%20Nightjar.craft?dl=0 This is the plane as it was before my 'optimization' attempts, trying to 'area rule' this thing, lol
   
3. and just for giggles, this is the latest original stock aero version; also still WIP: https://www.dropbox.com/s/og1cbmtejmxyvz8/GAD%20X21-1%20Nightjar%20%28stock%21%29.craft?dl=0
   

Thanks everyone!

[FourGreenFields]

Allright, so when I stumbled upon this challenge a few days ago, it really made me want to try out FAR for the first time ever, and I've been having a great time! Thank you so much! What this also means is that I'm a total newb with this mod. To be perfectly honest I kind of still am one with KSP aircraft building in general, so pls be gentle.

I had been tinkering around with a new jet in stock which looked promising, in fact I should say it was my new favourite original plane design and for something I made, it's been flying quite well with the new stock model. 5 seconds after maiden take-off in FAR, however, guess what happened (exactly, it exploded). A good laugh, some flights with way better planes from other people and about a dozen (ok more, many more) revisions later, I *think* I met all the criteria, except maybe one (TWR, see pics).

Here goes:

http://imgur.com/a/MpcrP

I won't bother counting score at this point as I'm not even sure if I did things right with this challenge. And there are of course many many problems with this design and I'll gladly appreciate any help from people with actual experience with FAR or aerodynamics in general to improve on it. Some of the more pressing ones are, roughly in order of importance:

• Transsonic design. Wave drag area is 1.07, which I have managed to bring down from 1.38 by doing the ape-on-a-typewriter dance with the offset tool but I will *not* pretend that I had *any* idea what I was doing. I just watched that one vid from earlier in this thread and then fiddled around trying to make the number go down. I *think* the undercarriage has the most potential for optimization, but I honestly have no idea how to get it below 1, let alone into the regions some of you have achieved (which I'm totally aware won't be possible with this design)
  
• Rudder settings, or actually control surface settings in general. Yaw is the biggest one though. I've already set it down to 5, but I still get the feeling that it might be too sensitive as the plane is hugely sensitive to combined yaw-roll maneuvers of any kind and will very quickly go into a spin. Pitching up also leads to minor stalling quite often, but that may be normal? I don't know
  
• General stability issues above mach 2. The thing likes to deviate to all kinds of sides and generally wobbles around quite a bit. Might be connected to my first problem, might even be somewhat inevitable with how the wings are shaped and placed?
  
• Structural integrity. The nose likes to come off first. After that it's the main wings. The tailsection is apparently made of hardened unobtainium and almost never breaks. I know I could up the strength of the parts but that would then again ruin the TWR and probably the COM as well. Maybe there are some magic tricks that I'm not aware of? This is probably least important because I get that everything breaks at some point. It would be nice if the plane could withstand a little more though.
  

Here's the .craft-files:

1. https://www.dropbox.com/s/ljj0ndw71c96axg/GAD%20X21-3%20Nightjar%20%28transsonicpls%29.craft?dl=0 This is the most current version, the one I did try the challenge with
   
2. https://www.dropbox.com/s/o7ewojfy3skl7vx/GAD%20X21-2%20%20Nightjar.craft?dl=0 This is the plane as it was before my 'optimization' attempts, trying to 'area rule' this thing, lol
   
3. and just for giggles, this is the latest original stock aero version; also still WIP: https://www.dropbox.com/s/og1cbmtejmxyvz8/GAD%20X21-1%20Nightjar%20%28stock%21%29.craft?dl=0
   

Thanks everyone!

When thinking about the aerodynamic layout, try to achieve something like this for the cross section: https://en.wikipedia.org/wiki/Sears%E2%80%93Haack_body#/media/File:Sears-Haack.png You won't usually hit that, but when building for hypersonic, it's usually enough to get somewhat close to it.

It doesn't matter where the cross section is. Just look at the green line for transsonic design.

Then you do exactly what you already did - move stuff around a bit, and try to reduce wave drag area by a couple of 0.01m².

If you want to know more, google "area rule", possibly also "shockwave", or hypersonic airflow or stuff like that.

Rudder needs to be set for 0 roll reaction. Or, if you are experiencing loads of yawing against roll direction, to negative roll. Else you'll yaw against roll direction alot (you do anyway due to aerodynamics, but not nearly as much).

For stability, open the FAR user interface, and calculate the scary looking numbers for the speeds you are having problems with.

Well, only "magic trick" I know of is to keep stability high. That way you won't be able to pull many AoAs, nor induce too much side slip. That usually does a good job for preventing RUD.

Also, keep in mind that the engine power is always at a given speed and alt. At 0 alt and 0 speed it won't usually have max thrust. That's probably why you aren't able to lift off at full fuel load.

Gonna download your craft, and take a look at it.

EDIT: And make sure you raise the gear before calculating stuff. Also applies to area ruling planes (-> green line)

EDIT2: Ok, actually surprisingly well area ruled. Just 3 places which are definitly adding alot of drag:

The intakes. Ducting air through your plane basicly reduces cross section - in this case this means that the cross section reduces and then risies again.

Just behind the intakes the radial attachment points have a lower cross section - again, reduced cross section where you don't want it.

On the rear, where the wings end, there is a very steep reduction in cross section. Not quite sure how to solve that yet, at least without possibly leading to stability issues.

Also, it seems it isn't instable at Mach 2, so still gotta find out why it falls apart.

Edited August 1, 2015 by FourGreenFields

[Gnullbegg]

Hey thanks for answering!

Rudder needs to be set for 0 roll reaction. Or, if you are experiencing loads of yawing against roll direction, to negative roll. Else you'll yaw against roll direction alot (you do anyway due to aerodynamics, but not nearly as much).

Yeah I think I already have the "standard" config as in: roll control at the wingtips, pitch with control surfaces near the center of the craft + it's elevators and set the rudder as yaw-only. The problems mainly occur at pretty low and very high speeds. I guess it's kind of to be expected? It's just that when I combine a yaw and roll input that it goes into a spin very quickly. I have no idea if it's just supposed to be like that to the extend I am experiencing or if my control surface settings can be optimized still. Same with the minor pitch stalling and the oscillation of the nose, especially with SAS on.

For stability, open the FAR user interface, and calculate the scary looking numbers for the speeds you are having problems with.

I watched this:

video about the derivatives, it seemed to make some sense and I understood *some* of the terms, hah. I tried the same calculations at key speeds and heights as the youtuber did and saw mostly green, he also mentioned that a certain amount of red is to be expected. The vid was linked from somewhere in this post I believe. It's also fairly new, so I just assumed it is still accurate?

EDIT: And make sure you raise the gear before calculating stuff. Also applies to area ruling planes (-> green line)

Funny you mention that, with a few configs I had the situation occur that my wave drag was actually *lower* with the gear DOWN!? I totally didn't get that. How is that even possible?

And thanks a lot for taking a look at my craft!

EDIT1: Thanks for your hint with the intakes! My original design had a pair of structural intakes attached to the side of each radial intake, above and below the wings. It was just for looks, to hide the little bump the small deltawings make at the junction with the main wings. the first thing I'd do before take-off was to disable those 4 intakes to reduce drag. And the first thing I did after installing FAR was to take them off because I thought they were nothing but dead weight. I will re-add them and see if that actually miraculously solves the problem!

Edited August 1, 2015 by Gnullbegg

[FourGreenFields]

Funny you mention that, with a few configs I had the situation occur that my wave drag was actually *lower* with the gear DOWN!? I totally didn't get that. How is that even possible?

Might lower wave drag because they increase the number of voxels necessary to calculate with same precision. FAR will sometimes increase the size of the voxels for performance, which on the other hand decreases calculation precision, and that can decrease drag.

Or you built a plane that has a too low cross section where your gear is.

EDIT: Ok, managed to area rule tail section a bit better. 0.956m² by swapping the elevators mounted on the inside of the wings for Elevon 3s, and replacing the aerodynamic™ nose cone in the middle of the rear section, with a tail connector B.

EDIT2: 0.93m² by removing the twin tail fins, instead mounting a single tail fin of the same kind on the new tail connector, and 2 basic fins where the tail fins previously where (the latter partially because stability, but also for area ruling it)

EDIT3: Made an album for screenshots to show exactly what I did. Also rotated the intakes around a bit, and managed to reduce wave drag area to 0.80m² with that

Javascript is disabled. View full album

EDIT4: Also maxed the brake torque to be able to test whether the new tail leads to problems with exhaust damaging the tail, due to gimbal, while still on the ground, and to make the thing slow down faster during landing.

EDIT5: The basic fins might have been a bad choice... they lead to overheating problems. Still, managed to reach Mach 4.3 at about 13km iIrc.

Flies good, except for some wobble.

EDIT6: Btw: Mind to tell me how you set the thrust limit to exactly 50%?

Also, note to self: Find out why this thing doesn't overheat at Mach 4.6 at 12km...

Edited August 1, 2015 by FourGreenFields

[Hodo]

EDIT6: Btw: Mind to tell me how you set the thrust limit to exactly 50%?

Also, not to self: Find out why this thing doesn't overheat at Mach 4.6 at 12km...

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

I have mine set at exactly 50%, it took some messing around with but I managed to get it. I think it has to do with the settings the game is graphically and the mouse sensitivity, but I dont know... luck could be just as likely.

[tetryds]

Might lower wave drag because they increase the number of voxels necessary to calculate with same precision. FAR will sometimes increase the size of the voxels for performance, which on the other hand decreases calculation precision, and that can decrease drag.

Ok let me just fix this small misconception.

What FAR actually does is use a fixed ammount of voxels to map the craft.

This way you can have very good precision on small vessels, like reentering pods, and still have a good precision on big vehicles where small bumps would not do much.

Because of that, you get consistent performance when using FAR, does not matter the size of your craft, with resolution scaling properly.

[CrisK]

Here's a design for a navy multirole tactical fighter. The Grumann ASF-14. It has more than twice the range of the Boeing X-32 or F-35, but the armament capability is roughly the same. It's less maneuverable than the smaller fighters, but still very maneuverable. It handles extreme turns at speeds up to Mach 1.4. It's stable as an interceptor at speeds up to Mach 3.9.

I might install PEW so that I can equip it with AIM-54s.

Javascript is disabled. View full album

[Gnullbegg]

Btw: Mind to tell me how you set the thrust limit to exactly 50%?

I edited the craft file. I usually keep the hell away from those, but with this challenge I initially thought I'd need every little bit of thrust I could get. Yet I didn't want to 'cheat' by going 50.5 thrust. Turns out each engine's "ThrustPercentage" is pretty easy to find in the file.

So, I took your suggestions and went from there. I really like how the intakes turned out! I kept the original tailsection for the 'final version' (yeah, right) of the plane. Managed to bring drag area down to .5 eventually with a tail like you suggested, a little more wing sweep and a different nose. But that design needs so much more work that I will branch it out into another X plane for now.

Anyway, time to collect some points:

Javascript is disabled. View full album

That's a nice 44 points! I actually think I could even score a little higher with better piloting but who cares? I passed the challenge with my very first FAR plane, that's what counts for me.

Many thanks again FourGreenFields for showing me how to optimize Area rule!

EDIT: Right, forgot to add that I'd really like some honest opinions on how good (or bad^^) this thing flies now. Since my first post, I've tweaked the elevon settings and part strengths a bit and the plane doesn't break apart nearly as much anymore. It has lost some of it's maneuverability, but too not much I think. Try it out if you like!

craftfile https://www.dropbox.com/s/h3xvx088invrh1o/GAD%20M21a%20Goatsucker%20%28%2BDroptank%29.craft?dl=0

Edited August 3, 2015 by Gnullbegg

[Halsfury]

Hello! I'll be back soon when my vacation begins, I've still been flying and tweaking Darth's F/A-18 hornet and have found that it starts to become aeroelastic at 900mph EAS, so I will be tweaking it so it can make use of more speed at low altitude.

Already I think this challenge has produced fighters equal to some of the best real world aircraft, and Crisk that's amazing

Gnullbegg, I'll add your score is the plane really called the goatsucker?

[FourGreenFields]

Gnullbegg, I'll add your score

I'm sorry that I said that I think I won't add any more designs. I'll just assume that's why you overlooked (again ) my 2 BD armoury designs. Both designs on the previous page.

EDIT: Lelz, "with an interestingly named aircraft"

Edited August 3, 2015 by FourGreenFields

[Halsfury]

I'm sorry that I said that I think I won't add any more designs. I'll just assume that's why you overlooked (again ) my 2 BD armoury designs. Both designs on the previous page.

EDIT: Lelz, "with an interestingly named aircraft"

I just can't remember all the pages and the stuff in them, or I haven't even checked,

I like the tiny one, it looks like suicide to fly it but did it really land?

I'll add the scores no problem

[CrisK]

Here's a work in progress. The Northrop ATF-23, a plane that was never built. Two YF-23 prototypes were built.

All of the weapons are internal to maintain stealth. Infernal robotics action groups deploy 6 AMRAAMs, 8 sidewinder missiles, and 2 hellfire missiles. There's room in there for another row of smaller missiles or a single cruise missile, but I frankly don't want to have that many infernal robotics action groups.

It's super-maneuverable, but not as maneuverable as the X-32. It's more maneuverable than the ASF-14 (largely due to the fact that the wings on the ATF-23 are fixed).

The flaps, ailerons, and all-moving V-tail work exactly like the proposed design. The ailerons affect roll, the flaps slightly affect pitch, and the V-tail controls pitch and yaw. It's stable up to Mach 2.9. I borrowed a neat idea from the original design: the brake action group causes the ailerons to deflect upwards and the flaps to deflect downwards, creating built-in balanced and stable airbrakes.

Javascript is disabled. View full album

[Gnullbegg]

is the plane really called the goatsucker?

Lelz, "with an interestingly named aircraft"

Hahah, well you can list it as just 'GAD M-21a' if you want but yeah I quite like the nickname! It's reminiscent of some of the NATO reporting names for 4th Gen Soviet fighters, which I took some inspiration from. It's also synonymous with Nightjar (the dev version's name) according to wikipedia. I will neither deny nor confirm any intentions of hilarious slightly self-depreciating innuendo of any kind.

[HafCoJoe]

would this plane count? The Fighter version and not the 4 Engine VTOL.

[VR_Dev]

Haven't tried any of these in far but I like my odds in this challenge.

cb_co Fighter Craft

[RocketTurtle]

Look at all of you with your fancy planes... and everything I build dies in 7.3 seconds...

*sobbing*

[VR_Dev]

Look at all of you with your fancy planes... and everything I build dies in 7.3 seconds...

*sobbing*

It's cool man, it took me a long, long time to even start attempting to build aircraft. Before I knew what to do I believed my craft wouldn't take off because they weren't going fast enough. I bet I had those things going 200+ before the end of the runway, and they still wouldn't take off.

Just remember to have the COL slightly behind the COM to begin with, make sure the thrust is lined up, then it's just up to your imagination. Also don't have the landing gear too far back.

And I've only played around in FAR a little, and it kicks my ass.

[RocketTurtle]

It's cool man, it took me a long, long time to even start attempting to build aircraft. Before I knew what to do I believed my craft wouldn't take off because they weren't going fast enough. I bet I had those things going 200+ before the end of the runway, and they still wouldn't take off.

Just remember to have the COL slightly behind the COM to begin with, make sure the thrust is lined up, then it's just up to your imagination. Also don't have the landing gear too far back.

And I've only played around in FAR a little, and it kicks my ass.

Oh I've been playing for 3 years, I get the basics, and can build great in stock. Every time I build a plane with FAR I try to make the wave drag really low, and I can, but my planes fly like crap.

I'm just bad at this I think, lol

[FourGreenFields]

I just can't remember all the pages and the stuff in them, or I haven't even checked,

I like the tiny one, it looks like suicide to fly it but did it really land?

I'll add the scores no problem

ok, thanks.

The "Firecrown" (named after a type of hummingbird, due to size and hover abilities) is quite easy to land, if you use the chutes, or are low on fuel. And ofcourse have some experience with VTOLs of this kind, or don't care where you land. Although touching down at about 10m/s it seems that the gear get's damaged and won't retract anymore

Main 2 problems of this thing are that it gets more stable as speed increases, so you can stall it at about 1/4 elevator deflection at lowish speeds, and that stall speed > max speed for supermaneuverability. Maybe I'll come up with a better design someday, maybe not. We'll see.

[Hodo]

Here's a work in progress. The Northrop ATF-23, a plane that was never built. Two YF-23 prototypes were built.

All of the weapons are internal to maintain stealth. Infernal robotics action groups deploy 6 AMRAAMs, 8 sidewinder missiles, and 2 hellfire missiles. There's room in there for another row of smaller missiles or a single cruise missile, but I frankly don't want to have that many infernal robotics action groups.

It's super-maneuverable, but not as maneuverable as the X-32. It's more maneuverable than the ASF-14 (largely due to the fact that the wings on the ATF-23 are fixed).

The flaps, ailerons, and all-moving V-tail work exactly like the proposed design. The ailerons affect roll, the flaps slightly affect pitch, and the V-tail controls pitch and yaw. It's stable up to Mach 2.9. I borrowed a neat idea from the original design: the brake action group causes the ailerons to deflect upwards and the flaps to deflect downwards, creating built-in balanced and stable airbrakes.

http://imgur.com/a/i0QRu

That is one good looking aircraft, but the missiles are cliptastic. I am surprised that the game doesnt just cause them to randomly explode like mine do when ever I attempt that without DRE installed.

- - - Updated - - -

Oh I've been playing for 3 years, I get the basics, and can build great in stock. Every time I build a plane with FAR I try to make the wave drag really low, and I can, but my planes fly like crap.

I'm just bad at this I think, lol

I would start with simple then work towards more advanced designs. I have one stock design that I use everytime FAR updates or there is a major update to KSP. It hasn't changed in 2 years, it is basically a Mig-21 SSTO design. It flies like a dart, it can go straight really well and as long as it is fast it will turn well, but as soon gets slow it gets really fun to fly.

It is simple yet works. Start simple then work to more advanced designs.

My most simple design that I use for pilot training early in the game is just a basic jet on the back of a simple airframe.

[CrisK]

That is one good looking aircraft, but the missiles are cliptastic. I am surprised that the game doesnt just cause them to randomly explode like mine do when ever I attempt that without DRE installed.

Each row is offset on the same plane so that they don't clip. If you clip them even slightly then they explode due to overheating.

[RocketTurtle]

That is one good looking aircraft, but the missiles are cliptastic. I am surprised that the game doesnt just cause them to randomly explode like mine do when ever I attempt that without DRE installed.

- - - Updated - - -

I would start with simple then work towards more advanced designs. I have one stock design that I use everytime FAR updates or there is a major update to KSP. It hasn't changed in 2 years, it is basically a Mig-21 SSTO design. It flies like a dart, it can go straight really well and as long as it is fast it will turn well, but as soon gets slow it gets really fun to fly.

http://i.imgur.com/bSFOg79.jpg

It is simple yet works. Start simple then work to more advanced designs.

My most simple design that I use for pilot training early in the game is just a basic jet on the back of a simple airframe.

I try. I die. .-.