antbin

Obsessive Technologies presents: our model 303 "Oak Smoke" This wonder of 20th century technology has just enough of everything, at a price that can't be beat. Our team of world class engineers is quite sure they can't unbolt anything else without it not flying anymore. Passengers: 72 + hitch-hiker in cockpit Engines: 3 x J-33 "Wheezly" (Extreme Edition) Fuel: 1460 kallons Parts: just 32! Separate ailerons can be removed at your own risk. Ladder included! (can be removed, but then you have to jump off) The same dead-simple aircraft can be painted two different colors and serve your fleet in as either (or both) a: Medium Regional Jet Cruising speed: 250m/s Cruising altitude: 8500m Fuel burn rate: .21kal/s Range: 1725km Supersonic Jet Cruising speed: 530m/s Cruising altitude: 5600m Fuel burn rate: .28kal/s Range: 2750km Comes with three handy action groups to help your underpaid staff fly it right: Action Group 1: Flaps. Deploy for takeoff and landing. Don't use while supersonic. Brakes: Brakes. Also deploys the air brake. "Abort": Thrust reversers. For use in case the brakes don't work. Also, it came free with the engines. The supersonic mode requires a microtransaction DLC, or else flying full throttle at around 2000m until you break 450m/s (or the plane). Supersonic climbs and cruise needs a smooth hand or fly-by-trim adjustment - too much swerving and you'll fall off the speedwagon. Super- or normal cruise is at a leisurely 90% throttle, with passengers protected from noise by the wings and the rear fuel tank. All for the surprisingly low price of 62,652,000 kerbucks! ( Download today! )

Inspiring challenge, but I (sadly) find my solution looking more and more like AeroGav's. 30 parts <L4 is very constraining! How do people prevent the wheels from burning off on the way back in?

Back in the pre-1.0 days, it was very handy to memorize the list of optimal Goddard speed / altitude combinations for launching rockets, so not to waste delta-V fighting drag / gravity. With the new 1.1 aero, is there any easy-to-follow launch speed/throttle advice?

One SSTO I made was so twitchy I had to fly it with only trim changes (alt-W and alt-S).

Hi Zaddy. If you want the engine to produce no thrust below 10km, and no thrust above 30km, then the second (thrust multiplier) column in your atmCurve would need to begin at 0 and end at 0 too. The first column (percent pressure) in your atmCurve would need breakpoints at 0,10,20(?), and 30km at least, maybe more. You can convert between altitude and atmospheric pressure with roughly Altitude = -5000 ln(percent Pressure) or percent Pressure = e^(-Altitude/5000). So 10000 is about 0.135, 20000m is 0.018, and 30000m is 0.0025. Maybe 0 0 ; 0.0025 0 ; 0.018 1 ; 0.135 0 ? The third and fourth columns are tangents - without a visual editor it's hard to see the implications of changing them. Doesn't Unity have an AnimationCurve editor?

Success... but only by turning the legs 90 degrees and landing on the sides of the feet. Ugly hack, but something for now. I think the drag was because the legs clipped into the aft fuselage. It would make sense for drag to be calculated based on if the part's DragCube sticks out of the bay, perhaps? I've had some problems with Gigantor solar panels that appear (barely) stowed but still pick up heat and drag.

I'm working on a SSTO Minmus miner, it's looking good except for how to land it. Dropping down right on top of the RAPIERS is one option, but better would be some temporary retractable landing legs at the back of the plane. Anyone seen a trick to stow big landing legs in a service bay? My attempt below doesn't work (the legs still pick up aero drag).

Metaphor uploaded it to KerbalX, you can try flying it yourself. My guess is probably not, I found that it is a bit intakeAir-starved and TWR (not drag)-limited. edit: Nevermind, shock cone OP

That thing lands like a feather leaf! Wow, that is the boundary-pushing that I hoped to see in this challenge. Wondering if the same design principles for a 3-wheeled manned craft could compete...

Welcome to the forums t3hJimmer and thanks for the entry! A nice tradeoff of speed and fuel economy. Eyeballing it on the scatterplot, at roughly 12.5 minutes and 100 fuel your plane looks like it gets a better fuel /time tradeoff than the group average!

Congrats juzeris, you have the honor of being first (and last) at both objectives... I wonder if going tiny is also relevant to speed, or whether highest wing-to-weight ratio is more important?

http://kerbalx.com/ is what you want! I've updated your scoreboard with your second entry.

Hi MathMog! Nice entry, capturing #2 in speed and fuel economy! I'm going to make a scatterplot one of these days, showing the tradeoff between the two. Nothing against probe cores in the rules, I didn't expect mass would matter very much in this challenge compared to aerodynamic drag. Still, smaller is better (until you have to land it!). Did you disable the front brake on your tripod plane? I find that's my biggest source of tipping over problems.

Hey, juzeris, great entry, and congrats for pushing KSP's drag model to the limit. By popular demand, sure, autopilots allowed, it's all good. As for the two possible exploits, I'd say neither gear in fairings or dry jet spinup are kosher. But gear is debatable, since the drag model is somewhat broken (you should probably keep it extended the whole time?). Anyhow, you're on the leaderboard... and if someone threatens your lead you could shave off some time by nailing that landing.

What a bullet, Crafter! I see 150 liquidfuel on takeoff, 35.61 on landing, so 114 units. I'm going to keep the challenge simple for now - but I'll put your craft's awesome features in the leaderboard! As for autopilot, if you really want to, post your entry and I'll make a MechJeb leaderboard. You can fly it yourself, I believe in you! The point of the challenge is to learn and share tips and tricks for making and flying great planes, having to deal with lift (takeoff), fuel (climb and glide profile), heat (cruising), and handling (landing). The turbojet is the 'middle ground' where you have to cope with all of these. I honestly don't know if doing sub-orbital hops is more fuel efficient than cruise... or if there's a low-thrust low-speed option... or if there's a way to deal with more heat to max out your speed at middle altitudes? Hoping we can try them all out and see how they compare!

Thanks for the interest. By "minimum clipping" I was trying to avoid entries like this one that clip everything *inside* an open cargo bay to exploit drag reduction. Good point about work-arounds for gear bugs. Fair enough, I'm not opposed to clipped entries as long as they don't make the challenge boring or single-solution. I'd love it for someone to start another challenge for RAPIERs. I would enter it. Probably everyone will find that sub-orbital-hops are the best RAPIER solution for fuel and speed. I hoped Turbojets would lead to more variety in designs and different speed/fuel tradeoffs since it's trickier to manage cruise heat at lower altitudes. It doesn't take much more than 10 minutes to fly between KSCs, it's not that boring, is it?

Congrats! In my limited experience with max cargo fraction, the most important measure of my ascent profile wasn't angle or altitude, it was climb rate. I tried to maintain at least 150 m/s vertical climb speed, which means gravity turning as you accelerate in the 8-18km powerband, but never letting your prograde level out at less than 5-10 degrees above the horizon. Milking the last bit of airbreathing speed at >20km is important, but not at the expense of losing your climb rate. You'll just have to spend more (heavy) rocket fuel raising your apoapsis again, while bleeding drag all the time. When you go for orbit, go for it!

> getting your throttle (and thrust) down is how you maintain a good supercruise fuel economy. This was true in 0.90, but I'm not sure if it is true in 1.x since fuel consumption is now proportional only to thrust (isp is fixed). Max thrust (and therefore fuel consumption) goes down with high altitude. High altitude means lower drag. In my experience, rather than throttling down, you should lower thrust by just flying as high as you can at full throttle (often therefore faster)! If you want to test your theories, why not try them in a turbojet fuel economy / speed challenge that is collecting dust... /plug

I couldn't launch metaphor's 50+% craft, so I tinkered with it to try and make it flyable for a crap pilot like me. Or perhaps I need to try a different day/nighttime for better air density? Anyhow: * Smaller payload: 52.16t * Smaller payload fraction: 45.4% (pad mass 114.77t) * More Skipper fuel * More aerodynamic nosecone (?) * Fewer (3) struts, attached from intakes upwards (so draggy bits get staged away) * Stable under SAS (little wobble) * Probe core instead of manned pod * Stageable turbojets (drop after 925m/s) Not sure if these are improvements, but at least they make it easier for a noob like me to fly. [[[ .craft file ]]]

My feeling is heat and risk of unplanned disassembly are both too low in 1.0.2

Good question. As far as I know, the ISP for air-breathing engines is constant now, and fuel consumption scales with thrust (not throttle or altitude). So for long flights the main thing affecting fuel economy is how little thrust you need to overcome drag. Full throttle at the highest altitude feasible seems (to me) to be the best for fuel economy. After exams, why don't you enter my fuel efficiency challenge and see whose designs work out best?

Wow, Metaphor, I can't duplicate the gravity turn with your craft... that is some tricky flying!

With good landing gear placement, not too hard... if I'd remembered to put the gear down, it would have been a clean landing too!

Nice graphs! http://imgur.com/yciepgi,Cp3Hk6P#0 http://imgur.com/Ngris7N

It's been awhile since I started a flying challenge. Now in our world of fancy thrust/speed curves and "realistic" aerodynamics, the challenge is even richer! High altitude? Full throttle? Suborbital hops? You decide: The Challenge: Fly to KSC2 on just one turbojet engine, quickest and/or cheapest! The Rules: (borrowed from Red Iron Crown) Propulsion by one turbojet engine only. No vernors, no RCS, no RAPIERs. Craft must take off and land horizontally on wheel(s). Stock parts only. KSP version 1.0.2 only, entries from 1.0 or before will not be considered. No cfg editing, save editing, debug menu, or any other shenanigans. No physics exploits (such as open-ended cargo bays or dry turbojet spinup). Please keep part clipping to a minimum. edit: clip away! At least two Images are required for entry, showing 1) MET zero on KSC runway with fuel load, 2) MET and fuel remaining stopped at (or west of) KSC2. Video or intervening screenshots to show how you flew encouraged. Craft files are encouraged so we can learn from each other's techniques. Permitted mods: Visual/immersion mods, informational mods, autopilots fine ya slackers Forbidden mods: Autopilots, anything that modifies stock parts, adds new parts, or changes the game's physics in any way. The Scoring: For time: Mission Elapsed Time (MET), landed, with speed ~ 0, at KSC2.You must be at or over the "finish line" between KSC2's VAB and launch pad. For fuel: Difference between liquidFuel on runway with MET0 and liquidFuel landed at KSC2. The Leaderboard: Quickest [table] [tr] [td]juzeris[/td] [td] - [/td] [td]0:11:15[/td] [td] - [/td] [td]Entry #3 - Puny Tim, landing took 25s![/td] [/tr] [tr] [tr] [td]juzeris[/td] [td] - [/td] [td]0:11:23[/td] [td] - [/td] [td]Entry #1 - Huge wings, red-lined temperature all the way[/td] [/tr] [tr] [td]The-MathMog[/td] [td] - [/td] [td]0:12:24[/td] [td] - [/td] [td]Entry #1 - Probecore with tiny, tiny, tiny plane![/td] [/tr] [tr] [td]TheCrafterESP[/td] [td] - [/td] [td]0:12:30[/td] [td] - [/td] [td]Tiny craft, 4.2t and 11 parts![/td] [/tr] [tr] [td]t3hJimmer[/td] [td] - [/td] [td]0:12:34[/td] [td] - [/td] [td]Shock cone and tiny wings[/td] [/tr] [tr] [td]Antbin[/td] [td] - [/td] [td]0:13:03[/td] [td] - [/td] [td]You can beat this![/td] [/tr] [tr] [td]The-MathMog[/td] [td] - [/td] [td]0:13:16[/td] [td] - [/td] [td]Entry #2 - Gentle 1/3 throttle ascent, tiny plane.[/td] [/tr] [tr] [td]juzeris[/td] [td] - [/td] [td]0:14:58[/td] [td] - [/td] [td]Entry #2 - Fuel-efficient Tim[/td] [/tr] [/table] Thriftiest [table] [tr] [td]juzeris[/td] [td] - [/td] [td]45.9 units[/td] [td] - [/td] [td]Entry #2 - One wheel, four canards, Porsche-sized trunk[/td] [/tr] [tr] [tr] [td]juzeris[/td] [td] - [/td] [td]59.4 units[/td] [td] - [/td] [td]Entry #3 - Mass matters if you want speed and efficiency...[/td] [/tr] [tr] [tr] [td]The-MathMog[/td] [td] - [/td] [td]67.7 units[/td] [td] - [/td] [td]Entry #2 - Two wheels and 1340m/s cruise![/td] [/tr] [tr] [td]Antbin[/td] [td] - [/td] [td]89 units[/td] [td] - [/td] [td]You can beat this![/td] [/tr] [tr] [td]t3hJimmer[/td] [td] - [/td] [td]94 units[/td] [td] - [/td] [td]144 fuel left over[/td] [/tr] [tr] [td]The-MathMog[/td] [td] - [/td] [td]98.7 units[/td] [td] - [/td] [td]Entry #1 - 150 unit tank on probe core[/td] [/tr] [tr] [td]TheCrafterESP[/td] [td] - [/td] [td]114.4 units[/td] [td] - [/td] [td]20-25km cruise, cherry orange[/td] [/tr] [tr] [td]juzeris[/td] [td] - [/td] [td]183.5 units[/td] [td] - [/td] [td]Entry #1 - Started with 240, huge tanks[/td] [/tr] [/table] - - - Updated - - - My entry to get us started: [[ .craft file ]]