GoSlash27

Welp... My latest design is an improvement over the current record, but "I'm disappointed. Not terribly, but still... it should've gone much further, much faster..." <--- old school nerd reference New unofficial record is 1,475@ 34 K.

Pretty much this. The high number of physics free parts lags the game and moving all those parts during the lag can summon the kraken.

After what I've seen in the Kerbin SSTO thread, I think an all- wing Eve SSTO ion glider is unworkable. Not because we can't find the correct balance of parts, but because any craft that could pull it off would be kraken bait. You would need a minimum of 12 panels per engine to make it run full tilt, but a realistic number for an Eve burn is going to be more like 36. Plus you've got more than twice as many wings and probably 3-5 tanks. Throw in all the cubic struts, and you wind up with a hot mess.

New record is 1,387.8 m/sec @ 33,221 m. 10% battery-free bonus. focker.craft

Just to let everyone know, we're running a parallel challenge to create an "all- wing" SSTO ion glider from Kerbin. This eliminates any possibility of infiniglide by restricting entries to one locked vertical control surface. If we get one into orbit there, then this just might be possible.... Regards, -Slashy

I just upped the game *evil grin*... My new unofficial record is 1,402 m/sec @ 33,501 m. I'll post an official entry tomorrow.

I use 1, with a couple 48-7S available to give additional punch when I need to make more rapid DV changes. I would personally never use more than one LV-N on an interplanetary driver. Best, -Slashy

Either of those would be fine. Best, -Slashy

It would be acceptable, but it can't be your wing. You can only use one, it must be vertical, and it must be locked. The reason we chose this rule is because any control surface as a wing will exhibit "infiniglide" properties, even if the designer tries very hard to not have it present. See GMiddlemass's entry below. We already know that ion gliders can make orbit with control surfaces as wings. This is to see what can be accomplished without them. Best, -Slashy gmiddlemass, Sadly, we cannot accept this entry. Control surfaces cannot be used as wings in this competition. You are permitted the use of one control surface as a rudder, and it must be locked. Best, -Slashy

That's one milestone down and very close to another. Way to go! I'll wait for your post before filling in your stats.

Tsevion, have you experimented with various ratios of wing to engines? Does there seem to be an optimal ratio there for the different types? I don't know how to do infinite fuel... If we can show that adding wings makes things worse instead of better for an infinite fuel supply from 1 tank, then it would conclusively prove that ion SSTO is impossible without control surfaces as wings. Best, -Slashy

^ Derp! Guess what happens to be at that location...

The guy who made the image says it doesn't mean anything. Having said that, SPOILER ALERT! If you don't want to see the image, do not click the link... http://i.imgur.com/IpHZC.jpg My thoughts on it will be below in white text... It bears a strong (I'm sure not unintentional) resemblance to the plaque we put on the Pioneer probes. I would imagine that it means what the pioneer plaques mean; each part corresponding to their counterpart. The Martian sentient species has (or had) 4 distinct genders. I think this was the case in Heinlein's book "Red Planet" and may have been the inspiration. The vertical arrangement of dots says that They lived on the 3rd planet in the system. Maybe this means Kerbin, or maybe it means that Moho didn't exist back when this easter egg was made. The pyramid and beam would imply that this signal was being sent to Kerbin (blue dot the intended recipient). The geometric figure would be a map of something. On the Pioneer, it's the map to find Sol from the center of the galaxy and known pulsars. What it was supposed to mean in the game... I think it was supposed to lead to a point on the surface of Duna where they lived. My guess is the big dot is Duna and the little dot is Ike. Handy because Ike is in a nearly perfect dunasynchronous orbit. If this is the case, there would be something 60* west of the latitude where Ike is directly overhead. Best, -Slashy

Kokanee, Sorry, but entries cannot have any kind of controlled wing or surface on them other than a single vertical rudder. The advanced canards disqualify this one. -Slashy

I'll go first to get the ball rolling. 831 M/sec @ 29KM altitude. Launch profile for this run: After takeoff, accelerate to 50 M/sec Increase pitch to maintain 50 M/sec until 17 degrees is achieved. Maintain 17 degrees pitch until end of run. manta 2.craft

What Claw said; you don't want your center of lift directly over your center of mass. You want it a little behind so that the plane will nose down if you lose lift, causing you to gain speed and restore lift. Best, -Slashy

Try looking at it as "thrust to drag" instead of "thrust to weight". The most efficient stock wing yields a theoretical maximum of 3.17 lift to drag (low alpha and high speed) This means it's efficiency is a maximum of 68%. In practice, it will be below this. The cheapest cost of picking up a kilo using wings is 320 grams of drag. The cost of the wings themselves is negligible in this case, since their parasitic drag is so tiny. So you need (in theory) a .32 t/w ratio minimum, but in practice it will be higher than that. Compounding this is the fact that the optimal AoA varies with the mass being lifted. A higher wing load yields a lower peak efficiency at a higher AoA and more drag. A lower wing loading yields the opposite, but you have to go faster to maintain the same rate of climb, which makes for more parasitic drag. It's sort of thrust to weight... but also not. Best, -Slashy

This challenge was suggested as a preliminary to another challenge, so I'll post it here. We're looking to establish speed and altitude records for "all- wing" ion gliders, in hopes that somebody will eventually succeed in putting one in orbit. The rules: -Stock parts only. -Stock physics only. -Aircraft may only be powered by ion drive. No RCS thrusters allowed for any purpose. -Aircraft are permitted the use of 1 control surface for use as a rudder, but it must be vertical. It must be locked during submitted runs. -All lift is to be provided by "wing" or "winglet" in any amount or configuration you choose, but "controlled wings and surfaces" are disallowed except as above. -No using loopholes in the physics, such as GOAP drive, kraken drive, infiniglide, Reaction wheel copters, etc. -No staging allowed. The entire assembly must remain intact throughout the run. Likewise, no mid-air refueling or catapult launches. *ADDENDUM*: Staging for the purpose of boarding manned flights is allowed (decoupling a capsule containing a pilot for boarding a command chair), but the vehicle must be stationary on the runway after the staging event. -Flights must start on the runway at KSC. You may elect to take off in any direction you choose, or even circle above KSC if that's your preference. -You may use all the physics-free parts you want, but bonus points of 10% will be awarded to entries that use no stand- alone batteries. Scoring: Entries will be ranked by a) maximum altitude achieved and maximum groundspeed (or orbital velocity, as applicable). There will be separate categories for manned and unmanned aircraft. Photos of runs submitted for ranking should be provided in this thread, and copies of the entry aircraft made available for verification. Good luck and somebody *please* make orbit! -Slashy Leaderboards KSP 0.25 Rank / user name/ ship name / record Kollier trophy for Ion pure wing speed (Manned): 1) Tsevion "Ionic Symphony XI" 77x70 KM Orbit achieved <-- First to achieve orbit! 2) Tsevion "Ionic Symphony IX" 2,124 M/sec 3) Tsevion "Ionic Symphony VIII" 2,000 M/sec <-- First to break the 2K barrier! 4) GoSlash27 "X-12B Kthulu" 1,938 M/sec 5) MabDeno "Triple Dart" 1,890 M/sec 6) The Rocketeer "Shrike III" 1,284 M/sec 7) GoSlash27 "YERTL 2" 1,271 M/sec 8) The Rocketeer "Shrike II" 1,003 M/sec <-- First to break the 1K barrier! 9) The Rocketeer "Shrike I" 686 M/sec 10) Syhrus "I-Flier" 494 M/sec Kollier trophy for Ion pure wing altitude (Manned): 1) Tsevion "Ionic Symphony XI" 77x70 KM Orbit achieved <-- First to achieve orbit! 2) Tsevion "Ionic Symphony IX" 70,459 M <-- First in space! 3) Tsevion "Ionic Symphony VIII" 53,271 M <-- First to break the 40KM barrier! 4) MabDeno "TripleDart" 40,301 M 5) GoSlash27 "X-12B Kthulu" 39,152 6) The_Rocketeer "Shrike III" 32,006 +10% battery- free <-- First to break the 30KM barrier! 7) GoSlash27 "YERTL 2" 31,340 +10% battery- free 8 The_Rocketeer "Shrike II" 29,717 +10% battery- free 9 The_Rocketeer "Shrike I" 26,621 +10% battery- free 10) The_Rocketeer "BION II" 25,369 +10% battery- free Kollier trophy for Ion pure wing speed (unmanned): 1) MabDeno "Double Delta" 146x88KM orbit achieved! +10% battery- free <-- First to achieve orbit! 2) GoSlash27 "Voyager III" 74x72KM orbit achieved! +10% battery- free 3) GoSlash27 "Voyager II" 2,294 M/sec +10% battery- free 4) GoSlash27 "Voyager 1" 2,152 M/sec +10% battery- free <-- First to break the 2K barrier! 5) MabDeno (No name given) 1,992 M/Sec +10% battery- free 6) GoSlash27 "Spirit of Kerbin City" 1,858 M/sec +10% battery- free 7) MabDeno "Bi-Triplane" 1,203 M/Sec +10% battery- free <-- First to break the 1K barrier! 8) MabDeno "Kuttle Fish" 939 M/Sec +10% battery- free 9) Lesto "ione2Battery" 930 M/Sec 10) Viragos (no name given) 760 M/sec +10% battery- free Kollier trophy for Ion pure wing altitude(unmanned): 1) MabDeno "Double Delta" 146x88KM orbit achieved! +10% battery- free <-- First to achieve orbit! 2) GoSlash27 "Voyager III" 74x72 KM orbit achieved! +10% battery- free<-- First all-wing ion glider in space! 3) GoSlash27 "Voyager II" 67,815M +10% battery- free 4) GoSlash27 "Voyager 1" 46,759M +10% battery- free <-- First to break the 40KM barrier! 5) MabDeno (no name given) 44,841M +10% battery- free 6) GoSlash27 "Spirit of Kerbin City" 37,082M +10% battery-free 7) MabDeno "Bi- triplane" 31,974M +10% battery- free <-- First to break the 30KM barrier! 8) MabDeno "Kuttle Fish" 27,430M +10% battery- free 9) Viragos (no name given) 25,858 +10% battery- free 10) Lesto "ione2battery" 25,940M Kollier trophy for Ion pure wing speed (Manned): 1)Monthar "Snoopy's Doghouse" 51.8 m/sec +10% battery- free 2)Monthar "The Red Baron" 48.4 m/sec +10% battery- free 3) 4) 5) 6) 7) 8) 9) 10) Kollier trophy for Ion pure wing altitude (Manned): 1) Monthar "The Red Baron" 7,262 M +10% battery- free 2) Monthar "Snoopy's Doghouse" 1,890 M +10% battery- free 3) 4) 5) 6) 7) 8) 9) 10) Kollier trophy for Ion pure wing speed (unmanned): 1) GoSlash27 "Living Dead Cat Mk.1" 1,455 M/sec +10% battery- free 2) GoSlash27 "Gaylord's Fokker" 1,388 M/sec +10% battery- free 3) Tsevion "How Ionic VII" 1,123 M/sec +10% battery- free 4) Tsevion "How Ionic VI" 1,022 M/sec <--First to break the 1K barrier! 5) GoSlash27 "Manta II" 831 M/sec +10% battery- free 6) 7) 8) 9) 10) Kollier trophy for Ion pure wing altitude(unmanned): 1) GoSlash27 "Living Dead Cat Mk.1" 34,450 M +10% battery- free 2) GoSlash27 "Gaylord's Fokker" 33,221 M +10% battery- free <--First to break the 30 KM barrier! 3) Tsevion "How Ionic VII" 30,628 M +10% battery- free 4) GoSlash27 "Manta II" 29,015 M +10% battery- free 5) Tsevion "How Ionic VI" 29,319 M 6) 7) 8) 9) 10) Honorable Mention 1) Yakky "Ion Ultralight" Achieved 79x225 orbit ... FAR aerodynamics used

I think it's a fine subject for a new challenge! It should help development for this challenge as well. -Slashy

I would say that refueling during the ascent would be staging if the refueling vehicle detaches, though I'd like to see it done! Likewise for the mass driver; it imparts energy and doesn't go up with the ship, so it's a stage. I'd also consider a reaction wheel 'copter to be cheating the physics engine, but highly entertaining...

Limitations in the KSP aerodynamics is the short answer. IRL the center of pressure (where the drag comes from) is never at the same point as the center of gravity, whereas in KSP they're always at the same place. This makes "weathervaning" impossible in KSP, which is a large part of the reason why the real shuttle is dynamically stable on reentry. For wings, the center of lift and center of pressure move around and the center of lift is always ahead of the center of pressure IRL. In KSP, they're all in the same place. And as I mentioned earlier, the drag physics for wings are wonky in KSP. Put all that together, and you have a reasonable shuttle IRL that's dynamically unstable in KSP. First thing I do is balance beam the fuselage so that the center of mass is exactly the same as the center of mass for my fuel tanks. I hook a rig up to it exactly at the center of the fuel tank until it balances on knife edge. This assures that the center of gravity won't move as the tanks drain. For high speed flight, I set the wings so that the center of lift is level with the center of the fuel tank and maybe throw in some dihedral on the outer wing panels to make it dynamically stable in roll. Placing the center of lift on the same axis as the center of the fuselage's mass eliminates the dynamic drag instability of KSP. Then it's a matter of taste for how far to put the lift behind the CoG. The further back, the more dynamically stable it will be in stall recovery, but the less efficient your aircraft will be since it has to create drag to counteract the nose-down tendency. For what I'm doing, I place it exactly at the center of mass for maximum efficiency and minimum control input. In your case, you want it back a bit. Best, -Slashy

Tsevion, Do you happen to know what the current record is for an all wing SSTO? That is, no control surfaces used as wings? I'm at 875 @ 29.5 Km and I'm not sure further improvement is possible... Thanks, -Slashy

Just out of curiosity, what's the record for a single stage with no horizontal control surfaces? I'm up to 875@29,500

I've reviewed that thread. The math in the OP is dead on, but the ramifications of what it means seem to be off. Most parts have the stock drag coefficient of .2. This is multiplied by .008 and the mass of the part to give a "true" drag coefficient. Then it's plugged into the classic drag formula 1/2*p*v^2*Cd. Wings are more complicated. They have 2 parts to their drag, parasitic and induced. The parasitic drag works normally, except that it is multiplied by .02 instead of .2. This is critical to understanding how forces operate at speed in a KSP aircraft. The wings are already a fairly low-mass assembly, but that .02 multiplier means that parasitic drag from wings pretty much doesn't exist! I mean... it *does*, but it's so miniscule that it can be safely ignored. The induced drag is a function of angle of attack. sin AoA * Cdi * p * v^2 At high angles of attack, high velocities, and high pressures, this value is huge. It can be much higher than the parasitic drag of whatever you're lifting. This can cause bizarre and counter-intuitive behavior that wouldn't be readily apparent, like shuttles flying backwards on reentry even though the CoG is ahead of the CoL. Lift works almost exactly the same way as drag, except the AoA formula is a bit convoluted. It's not exactly correct, but I crib the function as Cl*sin(2*AoA). The wing produces no lift at zero incidence to the airstream and no lift at 90 degree incidence, with a maximum lift coefficient at 45 degrees. Again, this isn't exactly how lift works, but it's close enough for planning purposes. What's critical to understand for our needs is that any aircraft can be analyzed for efficiency by simply dropping the "p*v^2" part and just looking at how it behaves in a global situation in any angle of attack. Lift is Cl*sin(2A). Induced drag is Cdi*sin(A) and parasitic drag is mass of the aircraft (ignore wings)*.004; a constant. If you plug these into a spreadsheet, you can see how a combination will behave for a given AoA. You can see which angle of attack yields the most lift for the least drag (most efficient) and what that ratio will be. You can see where drag from the wings overcomes parasitic drag, which tends to cause instability. Long -> short, the efficiency of a wing isn't determined by it's overall lift or lift- mass, but rather it's lift to induced drag. Best, -Slashy

I've been experimenting with high altitude/ speed ion gliders lately and have picked up a few things. It should translate to your problem... Drag from wings is much higher than parasitic drag from parts at high velocities. They tend to act as parachutes. Your low center of lift is probably to blame. First thing to go is typically yaw... If you can, try raising the wings and canards to the CoG height. See if that improves matters. Good luck! -Slashy