Kerbal aircraft drag race challenge

[Andetch]

3 hours ago, swjr-swis said:

Crazy TWR and guzzles fuel like there's no tomorrow... sounds like Vectors have entered the race. I figured we'd still be doing jets for a bit longer, wasn't gonna touch the rockets just yet.

Have you tried pitching straight up from take off (hint: SAS Radial Out), and letting gravity help you on the no-fuel return? Might be a better tactic with that kind of craft. How close to the runway do you dare to flare...

Yes, indeed vectors. Based around my Widowmaker SSTO project craft. All vector and no wing! 

You're very good at this ksp thing, if I may say so.

46 minutes ago, vyznev said:

FWIW, I'm going for the 5 second mark. Because that's how long sepratrons burn.

This is the unkerballed version; I'll need to mount a command chair on it and see if it can still break the 1 km/s mark, or if I'll have to add even more sepratrons.   Watch this space...

(Also, it flies back as a glider, and a pretty lousy one at that. And it has no brakes, so coming to a full stop is a bit tricky. But it can return and land intact, although it's not going to be breaking any speed records for that phase.)

There is a video of a land speed record using sepatrons. To give you an idea of how many it will take

https://youtu.be/Ph9zbfsYwA8

[swjr-swis]

4 hours ago, Andetch said:

There is a video of a land speed record using sepatrons. To give you an idea of how many it will take

https://youtu.be/Ph9zbfsYwA8

Hmm. No need to worry about high-G turns or risky landings... if one doesn't quite leave the runway in the first place. This could slash 'roundtrip' times by a good bit.

Note though, that rule 3 seems to make take off and landing mandatory, which would require the craft to be airborne even if it's just right over the tarmac for a split second. Plus @Klapaucius does remind us to keep to the spirit of the challenge and not simply build missiles. Looks like the fine line between 'piloted aircraft' and 'kerbal-payload-cruise-missile' may need some pinning down before people start teasing the spirit...

[vyznev]

5 hours ago, vyznev said:

FWIW, I'm going for the 5 second mark. Because that's how long sepratrons burn.

Well, as promised, here's the kerballed version.

Some might detect some similarity here with my entry to an earlier challenge. The main difference is that this time I'm using a lot more than just one sepratron.  In fact, this craft has a total of 126 of them, arranged in five rings of 24 each, plus six on the wheels to counteract their drag.

The craft can take off on its own from the runway; the launch clamp is only used to hold it still before launch, and to ensure that the mission timer doesn't start prematurely. For maximum velocity at the end of the burn, you need to turn nearly straight up immediately after launch. (In fact, holding the S key while launching is a good idea.) With a TWR over 18 at launch (and peaking at almost 81!), gravity is negligible compared to atmospheric drag.

With decent steering, the plane (barely) breaks the 1 km/s barrier at the end of the five second burn. Unfortunately, it only does so for a small fraction of a second, and I wasn't quick enough to catch a screenshot with the maximum speed visible on the navball.  

But the F3 screen does accurately report the "highest speed achieved" as 1003 m/s.

The glide back down takes a bit longer, as does slowing down using the "wheelie trick" (pitch up to make the wheel fairing drag on the ground). On this run, I managed to come to a full stop at 1:24, but several seconds of that were wasted precariously teetering back and forth on two wheels while trying to decide if I should keep the plane balanced that way or just let it fall on its tail.

More screenshots in the full imgur album. The .craft file is here on pastebin.

[Klapaucius]

3 hours ago, swjr-swis said:

Hmm. No need to worry about high-G turns or risky landings... if one doesn't quite leave the runway in the first place. This could slash 'roundtrip' times by a good bit.

Note though, that rule 3 seems to make take off and landing mandatory, which would require the craft to be airborne even if it's just right over the tarmac for a split second. Plus @Klapaucius does remind us to keep to the spirit of the challenge and not simply build missiles. Looks like the fine line between 'piloted aircraft' and 'kerbal-payload-cruise-missile' may need some pinning down before people start teasing the spirit...

The spirit is you have to fly.  I've clarified this with a new rule 11.

Interestingly, of course, the fastest 0-1000 planes are hopeless at part 2; that is a great leveler.  Having said that, I think I may indicate jet vs rocket in the stats and and award  a patch for both.

For me now, the most interesting will be shaving off the return time.  I think my plane has the potential for sub 45, but my skills are not up to the task.

 

9 hours ago, TheFlyingKerman said:

12s to 1000m/s

and managed to land back.

I am a bad pilot...

Well done. Is there a Kerbal in there somewhere in a command seat?

Edited July 22, 2018 by Klapaucius

[Klapaucius]

3 hours ago, vyznev said:

Well, as promised, here's the kerballed version.

 

Ah, floating parts. I built a fighter recently as a spoof on that :-)

Nice run!

 

[swjr-swis]

5 hours ago, Klapaucius said:

Is there a Kerbal in there somewhere in a command seat?

There must be: the resource panel shows 5 units of EVA Propellant, which corresponds with exactly one kerbal - I'm guessing in the fairing at the front of the central stack.

 

 

On 7/20/2018 at 7:47 AM, Klapaucius said:

11. You must completely leave the runway area. (No getting to speed, lifting off for .5 seconds and hitting the chutes).

I support the idea of defining more clearly what is a valid entry, but that phrasing presents a bit of a problem for those who pursue a mostly vertical flight path (like @vyznev and @TheFlyingKerman). I think they have good reason to go straight up with rockets, and no one would argue it wasn't actual flight... but the entire flight may happen above the runway, regardless of how far up they flew.

It's also indirectly setting an arbitrary limit on how fast we're allowed to accelerate - a bit strange for a 'drag race', perhaps. Theoretically at least, someone could feasibly add enough thrust to push a properly flying aircraft to 1000 m/s before the end of the runway; don't we want to see that?

 

Would it perhaps keep with the spirit of the challenge to simply state that valid entries have to a) be in flight for more than 50% of their run and b) come back to land in roughly the opposite direction they departed (thus requiring contestants to include a ~180 degree turn in there somewhere)? This would require a flyable and reasonably controllable craft, and incorporates a return leg. At the same time, it still allows for vertical flight and for the extreme accelerations people expect from drag races. Heck, if someone can actually fly horizontally to 1000 m/s, turn within the length of the runway, and still land intact in the other direction... I'm gonna be impressed.

Edited July 23, 2018 by swjr-swis
specifics are important :)

[Klapaucius]

@swjr-swis

Thanks for the feedback. Those are all good points.  I will revise the rules accordingly.

Edited July 23, 2018 by Klapaucius

[vyznev]

17 minutes ago, swjr-swis said:

Heck, if someone can actually fly to 1000 m/s, turn within the length of the runway, and still land intact in the other direction... I'm gonna be impressed.

If you mean above the runway, my craft can pretty much do that. In fact, in one of my test runs I found myself coming down just above the middle of the runway, and had to steer east a bit on the way down just to make sure I had enough room for a westward landing. (That was probably unnecessary, since the craft actually brakes quite well once you get the hang of it. But I was still practicing.)

Actually, I'd expect pretty much any entry with TWR much greater than 1 and sufficient control authority to be capable of that. Of course, since the runway is pretty narrow, it's easy to accidentally slip a few meters off sideways (and hard to know for sure whether you did or not). But basically it's just a matter of turning straight up after takeoff and coming back down the same way.

(I really should try to do another run and see if I can improve my return time. Looking at the leaderboard, I think I might actually beat at least a few other entries if I practiced the turnaround and landing a bit more.)

[Klapaucius]

@vyznev: see the revised rules. Turning above the runway--going straight up and coming back straight down--is just fine.  Your run is fine and legal. I'm just tying up loose ends.  

While I did not really intend it at the time, I think the return time has become the more interesting.  @ swjr-swis has demolished the rest of us on that.  My plane has the potential, but as I mentioned above, I don't have the landings down yet.

[swjr-swis]

22 minutes ago, vyznev said:

If you mean above the runway, my craft can pretty much do that.

I know; I meant in a traditional horizontal run. I was actually arguing to ensure your entry stayed valid, since that's exactly what happens when turning straight up to take full advantage of a rocket-powered craft.

 

25 minutes ago, vyznev said:

I'd expect pretty much any entry with TWR much greater than 1 and sufficient control authority to be capable of that.

Also, high-G resistance. My tests with a vector-powered craft, while getting amazing acceleration times, have so far resulted in complete disassembly in the turn, even though it was pulling considerably less Gs (50-70) than my jet-powered craft (130-155). Extreme strutting makes zero difference, which leaves me a bit puzzled as to where the structural failure begins. I'll have to try something else.

 

32 minutes ago, Klapaucius said:

@ swjr-swis has demolished the rest of us on that.

Well, I hold or claim no patent on my flight profile, use it to your advantage. I do it flying pure stock with mouse and keyboard, arguably the worst control method for planes. I think it's within everyone's reach to replicate it, as long as your aircraft is balanced/stable enough so it can pull a high-G turn with minimal unwanted roll/yaw (the less to correct when coming out of the turn, the better).

• This may sound silly/suicidal, but it helps a lot: rotate your view to watch your plane from the front! If your aircraft has even a bit of lift, you won't need more than a light tap to get airborne, and there's nothing but flat runway/ocean 'behind' you, so as long as you keep level or climbing, you're good. Being able to watch your alignment with the runway the whole run is a major advantage for the return leg though.
• Fly the speedrun as low and level as you can/dare
• (optional for very high-TWR craft: cut throttle right before the turn to keep it tight)
• Pitch up hard until just past inverted - this should leave your alignment with the runway mostly intact
• Roll upright and adjust runway alignment while still slow from the turn - it becomes increasingly difficult to be accurate as you pick up speed again
• (power up again if you cut throttle for the turn)
• Try to get down to about 100-150m and level out as best you can - this may be the hardest part, as the control authority needed for the tight turn hinders fine control here
• Cut throttle/brake as late as you (and your airbrakes) can handle

Actual airbrakes stick out a lot and can get damaged at landing, and are slow at deploying - I can very much recommend my 'cargo bay airbrakes' as a very effective, instant-deploying, and safer alternative for hairy landing scenarios. They can produce even more extreme stopping power by adding additional sets of elevons. Copy away - they work!

[Andetch]

2 hours ago, swjr-swis said:

Actual airbrakes stick out a lot and can get damaged at landing, and are slow at deploying - I can very much recommend my 'cargo bay airbrakes' as a very effective, instant-deploying, and safer alternative for hairy landing scenarios. They can produce even more extreme stopping power by adding additional sets of elevons. Copy away - they work!

KSP at it's best.... The programmers make parts with one thing in mind, then the community uses them for something completely different! Cargo bays for air brakes, SRB for structural space station parts....the list is long and varied!  

[swjr-swis]

1 hour ago, Andetch said:

KSP at it's best.... The programmers make parts with one thing in mind, then the community uses them for something completely different!

I consider it Applied Physics. You're selling yourself short if you don't use KSP's specific brand of physics to the fullest advantage.

Although a 'cargo bay airbrake' may also work in real life - if the fuselage doesn't get torn in two when it's engaged.

[Andetch]

I am sure that cargo bays opening IRL will provide some airbrake qualities.... The Early 747's had an issue with that, and I think the DC10 ? 

[TheFlyingKerman]

I think my total time can be greatly improved. I just don't have the piloting skill.

To reach 1000m/s in 12s start the engines, then pullup 35-40 degrees and retract the gears. Turn to prograde.

After reaching 1000m/s I cut the engines and pitched down 180 degrees, so I was reversing course flying upside down.

https://s26.postimg.cc/wtnuc4gvd/screenshot77.png

Then I rolled 180 degrees to land.

Anyone want to give this plane a try?

https://kerbalx.com/TheFlyingKerman/Aero-challenger-1A

[swjr-swis]

8 hours ago, TheFlyingKerman said:

I think my total time can be greatly improved. I just don't have the piloting skill.

To reach 1000m/s in 12s start the engines, then pullup 35-40 degrees and retract the gears. Turn to prograde.

After reaching 1000m/s I cut the engines and pitched down 180 degrees, so I was reversing course flying upside down.

https://s26.postimg.cc/wtnuc4gvd/screenshot77.png 

Then I rolled 180 degrees to land.

Anyone want to give this plane a try?

https://kerbalx.com/TheFlyingKerman/Aero-challenger-1A

 

Ok I gave it a run (why still on the pre-release btw?). I managed 0:11 on the acceleration and 1:12 to a full stop on the first attempt. I meant to follow your flight profile, but executed my own flat run instead; since it actually made it quicker, I didn't retry with a more vertical profile. I also cut throttle right before the turn and used the tiny bit of left-over fuel to get a small boost once pointed back at the runway.

I was lazy though and didn't add a gantry to board a kerbal, so it was instead simulated by a 0.1t dead weight in the seat.

Spoiler

Placing a 0.1t part in the pilot seat to simulate the kerbal mass without having to board manually. Otherwise the craft is left as created by TheFlyingKerman.

Muscle memory kicked in and I flew my own flat profile instead of pitching up 40 degrees. This actually shaved off a second though. 0:11.

This craft does not have enough fuel to return on full throttle, and it has almost no (air)braking capability, which makes slowing down after touch down a slow process.

Still, it's possible to land it safely and be at standstill in 1:12.

All parts accounted for. The return leg can still be optimized by a lot with some design tweaking.

 

[vyznev]

17 hours ago, vyznev said:

(I really should try to do another run and see if I can improve my return time. Looking at the leaderboard, I think I might actually beat at least a few other entries if I practiced the turnaround and landing a bit more.)

Well, I got it down to 1:07.

I think a return time under one minute may well be possible with this craft, but it's going to take some more practice. The critical moments are stopping the ascent after the burn ends (which also affects the peak altitude, and therefore the time needed to come down) and braking to a halt after landing. I'm sure there are still seconds to be saved from both.

[Klapaucius]

I've updated the leaderboard.

@swjr-swis @TheFlyingKerman I've put you in as a team time as well.

[swjr-swis]

44 minutes ago, Klapaucius said:

@swjr-swis @TheFlyingKerman I've put you in as a team time as well.

Uhm ok... wasn't really expecting it to be added to the leaderboard.

I guess I need to re-run with an actual kerbal in it then, before someone slaps us with the rules?

[Klapaucius]

3 minutes ago, swjr-swis said:

Uhm ok... wasn't really expecting it to be added to the leaderboard.

I guess I need to re-run with an actual kerbal in it then, before someone slaps us with the rules?

I think you are fine. Spirit of the competition has been maintained. Again, how come you don't use the Take Command mod?

[swjr-swis]

1 hour ago, Klapaucius said:

Again, how come you don't use the Take Command mod?

Awesome mod, but I play a pure stock game... I've become accustomed to it since I decided not to depend on mods anymore. I may have needed an intervention, as my last modded game had nearly 200 mods loaded and took 15 mins to load to the main menu. Leaves me more time to play, really.

 

1 hour ago, Klapaucius said:

I think you are fine. Spirit of the competition has been maintained.

I appreciate the sentiment, but I felt I had to anyway. Managed to get an even better roundtrip time too: 1:02. I hope it meets @TheFlyingKerman's approval despite the different flight profile.

 

Spoiler

Still 0:11 seconds to 1000 m/s

But this run came to a full stop at 1:02 (after some stomach churning braking maneuvers - some not entirely intended)

 

The recorded run isn't exactly a demonstration of model runway alignment... I had to do some extreme flaring to get my speed down to a landing-safe level. The finishing pirouette may not have been entirely intended, but it helped too.

Spoiler

 

 

 

Edited July 23, 2018 by swjr-swis
ping craft owner

[Brownie352]

I made a  jet  :  

  

[TheFlyingKerman]

9 hours ago, swjr-swis said:

I appreciate the sentiment, but I felt I had to anyway. Managed to get an even better roundtrip time too: 1:02. I hope it meets @TheFlyingKerman's approval despite the different flight profile.

 

That's great. Clearly you fly much better than I do. Feel free to fly whatever you like and add air braking (I didn't because I am hopeless with the overall time anyways).

As for why pre-release version I only have mobile data at home, and I still have a long science save (I have just got my rover to Eeloo the first time and set up a mining operation at Pol), so didn't bother to try upgrading.

[Klapaucius]

I spent a long time getting a bunch of projects up on KerbalX today, as well as entering @Triop's drag strip challenge. That inspired me o give Shirley another run.  I added smaller chutes and put the engine cutoff, gear, brakes and chutes all into one action group. I am still a long way from @swjr-swis, but I got in just under 1 minute!

 

 

[Klapaucius]

 @TheFlyingKerman, @vyznev, @swjr-swis, @neistridlar

I finally got around to making a badge for this.