donfede

Nice show samurai98 Can you share the craft file? Monty Droppings had been working on a similar "dark ion" craft, but I'm not sure if he concluded that project. Good to see that research being pushed ahead.

Nice, thanks for sharing! For the slow folk (like me), here is a link to a model (je je) of what Othuyeg modeled: http://www.fantastic-plastic.com/PhoenixWarpShipPage.htm . I still recall, and enjoy, the scene where Picard and Data get to touch the Phoenix ship . A fine re-purposing of our nuke arsenal.

Don't underestimate the difficulties of pushing a kerbal into orbit with ions. While their mass is not typically accounted for, it IS counted (0.09t) when using EAS Command Seats, and we're clearly seeing the value of a small payload/craft for this mission. I've been attempting (unsuccessfully so far) to design a craft around the less efficient Swept Wings (as Small Control Surfaces and Delta Deluxe Winglets have been done already). Below is my latest attempt, from this past weekend. I've paused (after spamming Small Control surfaces and adding MOAR ions), trying to figure out the best flight plan and AoA. Running Nedal's craft (thank you for sharing!), I see the value of the minimax-ing this mission. His 0.7t craft could achieve twice the velocity my 2.3t craft could, and still create less "Force drag" (as KSP associates that with mass). If Force lift matches Chevron Tango's post, i don't have good feelings about the potential to leverage lift over thrust (seeing v is squared for drag equations, and not for lift). O-doc's call for a TWR > ~0.35 for this mission, looks to be pretty accurate (Nedal's craft had 0.33 at takeoff, and 0.54 by orbit). That velocity is instrumental to getting up to 33km quickly, which is necessary to reach orbit velocity of 2300m/s before the sun sets (~60minutes from launch at sunrise). The alternative is to fly in a circle, but that requires even more fuel/mass and likely staging (kudos to Ziv for his success and detailed flight plan). As mass is key in this challenge, so are the mass-less parts, so I'll mention the new wiki page on mass-less parts. Looking closer at the thread, I see Redshift has also gotten a kerbal up using an ion flyer. Mission (kowigC09) pics, flown by Bob (while Jeb is away at Moho): Mods used: TriggerTech's Kerbal Alarm Clock Stock craft; designed and mission on v0.23.5 kif07-KMk6 craft (all control surfaces fixed) kdonfede -- "Adding K to every word..."

Thanks for sharing Jasonden, Salute to those heroes that paved the way into space for us. Here are a couple more links from NASA on Houbolt, one from this week, and another from a decade ago (they even have nice *chalkboard* drawings of the munar mission ). http://www.nasa.gov/vision/space/features/apollo_lor.html # 2004 http://www.nasa.gov/content/john-c-houbolt-unsung-hero-of-the-apollo-program-dies-at-age-95/#.U1hTiFc6KUk # 2014

<bump> This should be a "quick simple" improvement - that will help the community in their mission sharing pics.

The answer: TWR on runway must the over 0.35 ... Can you share any math on how you came to that number O-Doc? Thank you for posting your craft file. EDIT: with craft analysis Reviewing your craft, I get a TWR of 0.29 (mass of 0.702t [not including landing gear, which are mass-less in game]). Nedal's craft appears to have 0.26 TWR (mass of 0.782t). EDIT2: updated craft analysis So OX-S and cubic octagonal struts are mass-less in the game, at least up to a gross. The Z-100 batteries also appear to be mass-less, which is what I expect ihtoit was referring to. I now get 0.38 TWR on your craft, and 0.33 on Nedal's. EDIT3: ksp wiki docs on massless parts I was directed by xZise to the ksp wiki docs/page on massless parts. There are even more than I had expected (and I'm glad as this saves me doing more oscarb/ant tests). http://wiki.kerbalspaceprogram.com/wiki/Massless_part

I've no entry to submit yet (and am surprised there's not a FAR leader-board); regardless, below are my current attempts at preparatory math and data points for this challenge with stock KSP v0.23.5: # Review of the forces we are working with: weight, thrust, lift, drag NASA review of Wright 1903 Flyer and the forces that affect it (and our ion 'gliders'): # Weight Weight is dependent on 'surface' gravity at various Kerbin altitudes, and can be calculated with: Force of weight = mass * 'surface' gravity We'll focus on the 'surface' gravity for now. Pic with graph: Pic with equation, reference, and sample data points (apologies, I didn't have the patience to enter these into forum tables): Note the gravity values at 30km and 70km, 8.8m/s^2 and 7.8m/s^2 respectively. # Thrust Force of thrust = 2kN x <count of ion engines> I found it worth re-noting that 1N = 1kg*m/s^2. # TWR of PB-ION (source KSP wiki) [table=width: 500, class: grid] [tr] [td]part[/td] [td]mass[/td] [td]thrust[/td] [td]isp[/td] [td]TWR (Kerbin)[/td] [td]ellect/s[/td] [/tr] [tr] [td]PB-ION[v0.23.5][/td] [td]0.25[/td] [td]2[/td] [td]4200[/td] [td]0.815[/td] [td]8.729[/td] [/tr] [tr] [td]PB-ION[<=v0.23.0][/td] [td]0.25[/td] [td]0.5[/td] [td]4200[/td] [td]0.204[/td] [td]14.5476[/td] [/tr] [/table] However, TWR of a PB-ION is an incomplete picture. It's also worth reviewing the TWR of a PB-ION combined with its required energy source, and any additional mass for it to propel. # TWR and ion engine count, with necessary energy source (solar panels) source: reddit post by /u/Stinger771; note: his updated equation is slightly wrong (incorrect solar panel mass), but I only lurk reddit, so cannot contact him. From his work, we can get the number of ion engines (n) required for a TWR > 1, with various parameters: n = (m * g) / (T - i * g - s * g) n - number of ion engines required for positive TWR m - mass of other ship parts (ex: wings, command pod, xenon fuel) g - 'surface' gravity <see above> T – thrust of an engine; 2N as noted above i – ion engine mass; 0.25t for PB-ION [stock] s – solar panel mass <see table below; mass numX> Unfortunately, in our case this equation is still not complete, as the Force of lift from the wings allow craft with TWR < 1 to fly. Still, it provides a good starting point, and it confirms that ion craft cannot propel themselves against Kerbin's gravity until they are ~250km above the surface. # Solar panel review (given PB-ION electric draw of 8.729) The table below looks at the solar panels available, with their corresponding energy/mass ratios, and the count required to support an ion engine. While the OX-S static solar panels have the best energy/mass ratio, they (obviously ) have the drawback that they cannot move and track the light source. For our ion flyers they are a requirement, as we're contending with the Force of drag in the atmosphere, which breaks off extendible solar panels. The most important detail from this table is that we need a dozen OX-S panels to support one engine WITH optimal light, so designers must adjust appropriately. [table=width: 700, class: grid] [tr] [td]part[/td] [td]mass[/td] [td]electric[/td] [td]m/e[/td] [td]e/m[/td] [td]num for ion[/td] [td]num for ion (int)[/td] [td]mass numX[/td] [td]difference[/td] [td]mass numX2 (Jool/Eeloo)[/td] [/tr] [tr] [td]Gigantor XL[/td] [td]0.350[/td] [td]18.00[/td] [td]0.019[/td] [td]51.429[/td] [td]0.485[/td] [td]1[/td] [td]0.35[/td] [td][/td] [td]0.35[/td] [/tr] [tr] [td]OX-4L[/td] [td]0.018[/td] [td]2.00[/td] [td]0.009[/td] [td]114.286[/td] [td]4.365[/td] [td]5[/td] [td]0.088[/td] [td]0.263[/td] [td]0.175[/td] [/tr] [tr] [td]OX-Stat[/td] [td]0.005[/td] [td]0.75[/td] [td]0.007[/td] [td]150.00[/td] [td]11.639[/td] [td]12[/td] [td]0.060[/td] [td]0.290[/td] [td]0.120[/td] [/tr] [/table] # Lift Pic of table summarizing wing lift: As others have noted earlier in this thread, the small control surfaces have incredible lift/mass ratios compared to the other parts. Similarly, the swept wings appear to be more efficient than the delta wings. I'm currently exploring how to convert the lift figures above into a Force of lift value. This KSP forum post by ChevronTango suggests the following equation may work (quoting his post): Flift = CrossProduct(velocity, wingRight) * Cos(UpvAoA) * (1 - Abs(Cos(UpvAoA))) * Cos(AoA) * deflectionLiftCoeff * StaticAirPressure; where AoA is the angle between the velocity and the forward vector of the wing, and UpvAoA is the angle between the velocity and the upward vector of the wing, wingRight is the vector to the right of the wing as placed, or can be thought of as the cross product of the wings up and forward vectors DeflectionLiftCoeff is the lift value listed in the VAB StaticAirPressure <see below, at drag calculations> I've not yet worked numbers through this equation successfully, and thus do not yet have a good figure for Force of lift. # Drag The drag model in KSP is limited, but from their wiki we can see that the following equation can help us calculate its force: Fd = 0.5 Pv^2dA Pic of table with various drag calculations from test-flights: # Current and next steps As shown above, ion engines have a TWR > 1, only when gravity is less than ~5.5. But, gravity is not that low around Kerbin until one reaches ~250km altitude (clearly after wings are useful, as the flyable-atmosphere ends around 30km).(The variance is due to different possibilities, depending on solar panel type used.) My current questions include how much drag can the ion flyer craft overcome, and how high will the wings lift the craft, thus I'm pushing on improving those equations. In addition I may have some unit (or magnitude) issues above which I'm polishing. kdonfede -- "Adding k to every word..."

Negative Kyrian - I instead appeal another review from the race coordinators. "you must begin your race perpendicular" was not one of the original stated regulations (and a strategy I've used on all my runs so far). I do not comprehend what warrants the attempts to weed out race contenders, instead of focusing on progressing the race schedule. kdonfede

Don't expect TWR will pass without wing lift... but you're welcome to try and prove us wrong (I'm finishing up another challenge, but hope to make presence here sooner or later ).

Thank you Squad - For the great game, and for the recent (v0.23.5 arm release) improvement to the in-game settings changes; now the KSP screen no longer shifts back to the center of the screen, and instead remains where it was (as it should). keep the great work up, kdonfede

Can you elaborate Metaphor on your technique of sending a probe to equatorial orbit with a maneuver node? Looks like it's to save the step (and dv) of establishing LKO before burning for Eve. Did you use it for any inclination changes? Also, can you share how you identified the launch windows, or should this approach be repeatable for several Eve->Moho encounters? Edit: relevant link to this thread/discussion - describing gravity assists (including leveraging Eve's inclination) http://www.reddit.com/r/KerbalAcademy/comments/1or0d8/psa_how_to_gravity/

Nice pics and flight PLAD. Is your spreadsheet available? What were you thinking per program-wise? Had you considered forking/patching alexmoons coffeescript?

Kendin Kerman riding in krr02F-KMk2 completed race 3 with a lap of 1:22 (11:00 - 12:22). Raced in ksp v0.23.0 . Standing Start Crossing the finish line Path map, 2m line width The word from Kendin is that there are probably two to five more seconds that could still be squeezed out of the course, but he was hungry for snacks.

To save myself the hassle of finding it every race, below is my pre-race checklist. It takes about 15 to 30 seconds to calmly go through. <description> (<optional notes>) [<key-binding>] switch to Docking Mode [delete, or click the middle button on the bottom left controls] toggle docking to Translation mode [space bar, look for blue "UN" icon on bottom left controls] view switch to Camera CHASE [v] display Resources [click on top right controls] Persistent Trails - display controls [click on Persistent Trails footstep icon] Persistent Trails - display race guide track (with smallest 0.1 width; edit and Save Tracks if necessary) [click on "eye" for race guide; green to display] Persistent Trails - set High Precision [click on High Precision near bottom left] Persistent Trails - start recording [click on create new Track near top left] Persistent Trails - hide recorded track (to save CPU cycles) [click on "eye" for new recorded track; red to hide] Persistent Trails - hide controls [click on Persistent Trails footstep icon] display kerbal's name [right click on kerbal] ensure Precision Controls are disabled [caps lock; orange good; blue for Precision Controls] RCS enable [r] SAS enable [t] brakes off [b] prepare for starting screenshot [F1] Upon completing the race, Stop recording the Persistent Trails, and display the recorded track with a Line width of 2 meters. Review the run, and repeat [F5] as necessary.

Kasuha - you are sharp. Those of us that choose not to use mods such as mechjeb and ker, can simply take screenshots of mass (map view with expanded craft info) at key points. Calculating and presenting the math is simple (PM me if you'd like a sample libreoffice SS, but I've no doubt you can create a better one ).