Northstar1989

Trying to figure out how other ppl made the Harrier Distinction, and I must ask, where's the proof you made it Swifty? None of your screenshots show your craft moving at above 2000 m/s while below 40 km in altitude, and the flight log screen at the end was from the Molly Skycar one- and clearly shows you reached a 64 km altitude in that flight- which disqualifies that flight for the Harrier Distinction (as you may have only achieved that speed due to re-entry from higher low-orbit altitudes: thus why the rules say no flight above 40 km in the flight qualifying for the Harrier distinction). I'm not saying I don't believe you made it, but there's absolutely no proof- and honestly I'd like to see how you accomplished it and what kind of flight regimen you were sustaining at the time (making it at 60+ km is trivial, because at more than 4 scale heights further up, the atmosphere is less than 2% as thick as at 40km...) so I might figure out how to do it myself (simple jet engines WON'T cut it, but LFO mix for rockets is fairly heavy...) Regards, Northstar P.S. I wasn't mincing my words when I said "re-entry from low-orbit." Technically, a Low Earth Orbit, for instance, is one that passes THROUGH the thermosphere or exosphere- the uppermost layers of Earth's atmosphere. What defines it as an orbit is that it has both a periapsis and an apoapsis- not that it's stable. That's one reason why the International Space Station actually requires regular small burns to keep it "orbital"- because it is experiencing very small amounts of drag from the tiny amounts of air around it, as it is actually orbiting within the Earth's upper atmosphere- with a circular orbit around 420km, it never even leaves the thermosphere, and thus isn't in a 100% stable orbit. SOURCES: http://en.wikipedia.org/wiki/Low_Earth_orbit http://en.wikipedia.org/wiki/International_Space_Station http://en.wikipedia.org/wiki/Orbital_decay

And, forgetting about all my complaining on the rules for electrics for a brief moment, I proudly present my traditional, "Who Needs a Runway?", LiquidFuel VTOL; the K-5 (referring to the # of major revisions before a final design was reached) 'Blackbird'. Here the K-5 'Blackbird' is completing the first challenge: I know most of you may not believe this, but I think most of the challenges actually are doable with this design. The VTOL engines, when swapped for their rocket variety (and the plane equipped with a number of LiquidFuel drop tanks and the main tanks switched for LFO) should be capable of making orbit. The Kerbal-capacity challenges can probably all be met by carrying a couple lawnchairs strapped to the wings, or a couple passenger fuselages dragged below on a winch like cargo (the tricky part will be getting that off the ground in VTOL mode without flipping- although the total craft weighs about 18 tons fully-fueled- so that's less than 1/18th of vessel mass, and things could be further balanced with small "ballast" drop-tanks...) The cargo challenges- those will be tough (imagine dragging 7.2 tons below a Harrier- the closest real-life craft to this design!), but doable with variants stripping down the base-weight (by reducing the # of engines and swapping the main fuselage for a structural version) to a possible minimum of less than 12 tons (4.8 tons- that can be done...) And the Munar mission- even that's doable with the rocket-type VTOL engines in basically the current configuration of the jet VTOL's (though I'd probably strip off all the jet engines and, if allowed, intakes- to reduce the weight I'd have to haul to the Mun on a rocket...) The only mission this design might NOT be capable of is, ironically, the one it's closest real-life relative gives its name to: the Harrier Distinction (though, FYI, acutal Harriers don't come ANYWHERE CLOSE to making speeds of 2000 m/s- they can't even cut much above a tenth that- their max speed is around 1,100 km/h). The velocity-curves reduce even the stock turbojet engines to half-thrust by 2000 m/s, and the best plane in the Maching Bird challenge could only make 2400 m/s, with MASSIVE intake spam. It's virtually impossible for any plane to make this speed (the wings create too much drag)- what you really need is basically an air-breathing rocket or an actual rocket...

Yeah, I can understand the desire to try utilizing thermal turbojets- and the design actually makes some sense if you're trying to make something without any lift- but the electric category unfortunately effectively bans all forms of propulsion except electric rotors and ion engines (in fact, you posted too soon- I just edited a comment about that into my last post...) The only REAL difference between this and the HELO challenge then, since ion engines can barely lift themselves on the Mun, and not at all on Kerbin, is that you can utilize wings as large as you like... I asked for an exception there for TTJ's, but I *highly* doubt Fengist will grant it. And if he does, and takes ONE LOOK at antimatter TTJ's, with their 300 kN thrust and virtually infinite fuel-capacity at first glance (in reality, any knowledgeable KSP-I player will tell you that the real fuel is the antimatter in the reactor- which burns at quite an appreciable rate), he'll go right back to banning them. Better off to stick with fission. Why are you still playing in Sandbox, with the addition of Career Mode anyways? Career Mode really does serve to make things much more involving and challenging, and will only become more so with the addition of economy in the near future. And, if you're using KSP-Interstellar, you're better off with Career Mode anyways as the mod adapted so quickly to it that it's already became a primarily Career-based mod- with more features useful for it than for Sandbox. Good old Liquid Fuel is a solid choice. Or, if you want to stick with electrics, you're basically going to throw in the towel on several of the challenges- it's simply physically impossible to achieve the Harrier Distinction with electrics (they lose all thrust at 500 m/s), and unless you utilize some GIGANTIC wings relative to the rest of the craft, get to the island flying WEST around Kerbin, and utilize stock aerodynamics (forget about it with FAR) you're never going to achieve the DARPA-X award either... Oh and the Munar mission- impossible unless you design an all-ion extremely lightweight craft (think a command chair, an OKTO2, a single Xenon tank, a minimal # of structural parts, and at least 45 stock ion engines, with a 0.625 meter KSP-I reactor+generator), made solely for that challenge, you're never going to get that one either... Regards, Northstar P.S. I knew about the fusion reactors probably being upgraded because I have become VERY familiar with the KSP-Interstellar tech tree. In Career Mode, purchasing Antimatter Power provides access to upgraded fusion reactors- and I figured you were playing Career Mode like most KSP-I players seem to now... If you're playing sandbox, you have to individually upgrade each reactor last I checked- the reactor should be basic level by default... What does it say for the name of the reactor when you right-click on it?

I don't mean to be harsh- but what exactly is that? It looks like a giant metal box- and pretty much the sorriest, ugliest excuse for a "flying" machine I've ever seen. At least *try* to make it look aerodynamic, OK? And, "improving" it by using *antimatter* reactors? IMHO, they shouldn't even be allowed in these challenges at all- antimatter on the scale and control of those reactors is simply CENTURIES away, and most people who play with them either cheater them open in the tech tree or spammed thoughtless poorly-designed science missions until they unlocked the tech node. Understand, I'm not saying you did any of that- only that they're WAY too OP'd for most challenges. Personally, I have no problem with fission reactors an thermal turbojets- maybe even the upgraded sort that you don't unlock until fusion power- and perhaps even the basic fusion reactors in certain circumstances (I'm PRESUMING those are probably upgraded fusion reactors if you're talking about replacing them with antimatter- in fact I'd almost be willing to place money on it), but antimatter is certainly far too powerful and unrealistic for almost any KSP challenge not specifically designed for them... NOTE: I'm not even sure antimatter-powered Thermal Turbojets *ARE* allowed in this challenge. "Jets, rockets, and gasses" are explicitly banned- I'm pretty sure that includes thermal turbojets too, in practice limiting you to nothing but electric helicopter rotors and stock ion engines. In fact, other than the rather fatuous allowance for ion engines (which NOBODY in their right mind would ever use for a Kerbin VTOL challenge- they can't even lift their own weight and fuel, nevertheless the weight of their electrical generation equipment), the only difference between this and the HELO challenge is the allowance for large wings in the electric category. And many of the goals are physically impossible with those restrictions- such as making suborbital hops (SUBORBITAL? Pfhhhh, rotor-propulsion can hardly lift you above 20,000 meters if you're lucky) or a 2,000 m/s velocity (their velocity curves actually reduce thrust TO ZERO thrust at 500 m/s, and only 20% thrust by 425 m/s). Stupid and overly-restrictive, I know- I've already expressed much ire about them on the HELO thread. Sorry, I didn't make the rules- but I can comment on them. Regards, Northstar

Oh, if TTJ's are allowed, then its really no problem. Even a small amount of forward thrust that doesn't fall off with altitude like rotors do, near max altitude, would be more than enough to achieve 400 m/s- especially with a little bit of lift to help keep it aloft as well. For TTJ power and weight, though, it really varies a lot by the type of reactor you use... The thermal turbojets have a velocity curve that really only starts falling off after about 800 m/s (that's about 95% of orbital velocity on Duna- falsely leading a player who used them on the Flying Duna Challenge to conclude that they have no velocity curve, getting ALL KSP-Interstellar put in a separate category as a result, similar to all nuclear craft here... This is even though theirs is in fact a significantly less generous velocity curve than stock turbojets), and hit a peak ISP at around 5000-6000 m. Their maximum rated thrust of the jets is 300 kN- but you'll only ever achieve that with antimatter reactors (which it's difficult to obtain enough antimatter for to last more than a few minutes...) With the lowest-level standard fission reactors, they obtain about 35-45 kN with Uranium and 50-60 kN with Thorium. KSP-Interstellar just introduced a new reactor, however, which might be more powerful under certain operating conditions and with certain designs (you might have to keep the throttle down a bit, counter intuitively, to obtain maximum thrust- for instance...), and that is also a bit lighter. The KSP-Interstellar reactors are based on real-world designs (or proposed designs) and operating statistics, adjusted a bit for KSP-scale, but the basic 1.25m Uranium reactors with a full nuclear fuel load weigh 2.5 tons (the Thermal Turbojets themselves an additional 0.4 tons)- with a 10% fuel load you can get it down to 1.6 tons of weight with Uranium. I don't know how much the upgraded reactors weigh. Thorium weighs a bit less, but uses the same basic or upgraded reactor, yet I don't know how much Thorium weighs on reduced fuel load (which I highly recommend- the default, full fuel load of a uranium reactor is enough to last around a game-year on idle or over 7 months on full power- though thorium burns through a good bit quicker). You can adjust reactor loading via tweakables, or using a plugin like TAC Fuel Balancer after launch. Nice call using the Infernal Robotics part to rotate the rotors, by the way. Although, I'm curious though- did your rotors clip through the craft when you did that? Except for slightly-overlapping wing segments, I consider part-clipping anathema, and strongly avoid it at all costs- as I consider it to be "cheating". Even the HELO-B, if you look closely at a few of the close-up pics (I intentionally took some of the pictures to show this), doesn't have *ANY* part-clipping. I was particularly careful to make sure the rotors had clearance with everything in their path, including other rotors- if only a few centimeters' worth. Regards, Northstar

I've seen a number of questions by new players asking for advice from "experienced players" about the benefits of refueling depots and stops on the way to places like Jool and Eelo vs. straight transfers from Kerbin. There is a wide spectrum to the term "experienced player", and different players have different skill-sets and specialties. Speaking from the perspective of an experienced player who does a LOT of refueling, gravity-assists, and aerobraking; all to save fuel and Delta-V, I thought I'd try and clear this topic up a little for new players. Sorry if it drags on a little- I first wrote this at roughly 2:30-2:50 AM, though I've done my best to clean it up since... TECHNICALLY, it costs more Delta-V to do a refueling stop, and then continue on your way to your destination, than just to make a straight transfer, all other things being equal- but there are several EXTREMELY important exceptions to this that can make it a lot more worthwhile: (1) You can save a lot of fuel if the body you make your refueling stop around has an atmosphere. This may not seem intuitive, but aero-"braking" can actually be used to ACCELERATE your ship towards your destination. Let me explain this: -Take the example of Duna, for instance. If you set up a fuel depot in low orbit around Duna, and send a spacecraft from low-altitude orbit around Kerbin to Duna via a low-energy transfer; Duna will be traveling a lot FASTER relative to the Sun than your spacecraft by the time it gets that far away from the Sun... Now, when you enter Duna's SOI, you will have a large velocity difference, and appear to be traveling very "fast" relative to the planet- but from the point of reference of the Sun, it is actually DUNA that is traveling very fast relative to YOU. If you dip into the atmosphere around Duna, it will exert acceleration on your spacecraft to bring it closer to Duna's speed. In essence, you are performing an aero-boost, so to speak, relative to your final target Jool. - Now, if you got your fuel into Duna orbit in the same way (low-energy transfer and aerocapture) you will have saved quite a bit of fuel, as it is approximately 900 less Delta-V to make an ideal transfer to Duna than to make an ideal transfer to Jool (this ISN'T counting fuel-savings from a Munar gravity assist- which will save you close to the same amount of Delta-V on either trip if you perform it right). Now, it does cost approximately 1350 Delta-V to make a transfer from circular low Duna orbit to Jool- but you can make up quite a bit of that extra 450 Delta-V with a gravity-assist from Ike. Additionally, your approach speed at Jool will be lower when transferring from Duna instead of Kerbin (so it will take a lot loss fuel/aerobraking to capture) and you can make a MUCH more precise burn from Duna than from Kerbin (the burn-time will be shorter), which will more than make up the rest of that Delta-V in terms of reduced steering losses, reduced approach velocity, and less need for course corrections (especially if you are using NERVA engines...) Of course, this is where (2) comes in... - For BONUS fuel-savings, don't perform an aerocapture to Duna orbit- perform one to Ike. It's a bit tricky to pull off, but if you set you aerobrake such that your exit trajectory comes out with an apoapsis appropriately-oriented to Ike, you can perform an easy capture there, and save a lot more Delta-V than from capturing to Duna orbit- as it takes less Delta-V to make it from Ike orbit to Jool if you make appropriate use of the Oberth effect... (see below) (2) Craft design and the Oberth Effect: - The first, and most important thing you need to know about efficient spacecraft design is, the fuel-efficiency of your craft is *STRONGLY* connected to its fuel fraction. That is, it's not efficient to push around a bunch of empty fuel tanks or excessive numbers of decouplers. One of the main reasons off-world refueling is profitable is because it allows you to maximize the fuel-fraction of your spacecraft without a bunch of staging (which is both expensive and heavy- a 2.5 meter inline decoupler weighs and costs a LOT more than a Clamp-O-Tron docking port. And radial decouplers tend to be even worse...) Creating a partway stop for refueling along your mission route enables you to consolidate the number of vessels moving along the route from a larger into a smaller number as fuel is consumed- even if it's just a single fuel tanker and your interplanetary mission ship. Docking and fuel-consolidation has the same effect as staging: but is usually much lighter and cheaper. (you can dock two 100-ton vessels with nothing but a Clamp-O-Tron Jr: try using THAT to connect two 100-ton fuel sections in your mission vehicle, and see what happens...) Setting up a fuel-depot is of course heavy and expensive, but that's more of a one-time investment that you make for convenience, and isn't strictly necessary- your fuel tanker(s) *can* wait on their own at the refueling stop, and hook up with your mission vehicle directly. - Second, getting an accurate transfer burn to Jool from low Kerbin orbit is hard. More likely than not, you will need to perform a long, slow burn around Kerbin; followed by a shorter adjustment burn somewhere in interstellar space (MechJeb can help you find the optimal location for these adjustment burns, to minimize Delta-V costs. You could theoretically determine this yourself, but the mathematical equations required are nothing to sneeze at, and it will take a LONG time to locate the optimal adjustment points if you utilize trial-and-error course-plotting instead...) The fact is, the shorter a burn you have to make to get somewhere from Kerbin, the more accurate it is likely to be- simply by virtue of gravity having less time to curve you off-course during your transfer-burn. Additionally, there is something important you need to know about called the "Oberth Effect"... The Oberth Effect is a mathematical phenomenon that is EXTREMELY important to orbital mechanics. Without going into too much detail about it, you should know the basic result of it: the faster you are going when you burn your engines, the more energy you get out of it. What this basically means, in game-terms, is that it takes a LOT less Delta-V to get somewhere from a departure-point where you are already moving fast than in does to get there when you start out moving slowly. For this reason, you cannot simply find the difference between your current velocity and the velocity you need to be going at when you arrive at your destination to calculate Delta-V costs. The larger the Delta-V of a transfer burn from planetary orbit, the relatively less Delta-V it costs you compared to the final total kinetic and potential energy you will have at your final destination- as you will be moving quite quickly towards the end of your transfer burn. If you make a transfer burn from low above Kerbin, it costs you less Delta-V than if you first raise your orbit to the edge of Kerbin's SOI, and then make the transfer from there. It is actually for this reason that an *ideal* straight transfer (with no steering-losses: though such burns are, in practice, *impossible*) to Jool from Kerbin *theoretically* costs you less than a burn to Duna and then from there to Jool, assuming you didn't make use of Duna's atmosphere to provide you with a portion of your velocity. However, the Oberth Effect leads to one other important point you need to know about in order to understand why refueling (at Duna or anywhere else) can actually make sense: + Due to the way the Oberth effect works, the higher your acceleration is relative to the local gravity when you make a transfer burn, the less Delta-V it is going to cost you. This is actually for a rather simple reason, really- if your acceleration is much lower, your burn will be much longer, and you will make a greater portion of it in a more distant orbit from the celestial body you are departing. This means your average velocity during the burn will be lower (the further you are from a body, the lower your orbital velocity). Put another way, you have already lost a portion of you velocity from the beginning of your burn to gravity by the time you are nearing the end of your burn. I don't know how to explain this better- the greater your TWR, the less Delta-V you will spend reaching your destination, even before you account for the greater steering-losses to compensate for gravity-turning due to longer-burn time that a lower TWR also inevitably entails... + For obvious reasons (Duna's gravity is less than 1/3 Kerbin's), the same exact craft will have a much greater TWR around Duna than around Kerbin. What this means is, you will come a LOT closer to the idealized transfer of 1350 Delta-V from low Duna orbit to Jool's SOI than you will to the idealized transfer of 1915 Delta-V from low Kerbin orbit to Jool (you will lose less of your velocity to gravity over a burn of the same length- and thus your average velocity will be higher). Put simply, when you combine this with reduced steering-losses it's not 1915 Delta-v vs. 1060 + 1350 Delta-V (idealized transfers), it's more often 2100 Delta-V vs. 1150 + 1420 Delta-V. Just from this fact alone you will save some Delta-V with the same craft design, even before you account for the additional gravity-assist that Ike offers you the opportunity to make (from Duna orbit), or the opportunity to aerobrake directly into an Ike-intecept, and refuel around Ike rather than around Duna, which will make your Delta-V savings even greater... - I mentioned craft design earlier, and this is really another important factor to consider. In order to make a reasonably-accurate burn to another planetary system, you generally want to keep your burn-times to no more than 5-6 minutes (shorter if your departure orbit around Kerbin is REALLY low- I usually depart from at least 100 km or higher in order to make my transfer burns more accurate, and give my ships a little more breathing room to make rendezvous with fuel tankers or space stations for fuel, and sometimes crew, transfers before departure). Consider the following: + A craft with a TWR of 1 around Kerbin can accelerate at a little under 10 m/s^2. To make a transfer to Duna at that TWR would take a little over 2 minutes (assuming an expenditure of 1200 m/s Delta-V with steering-losses). For the same craft to make a transfer to Jool it would have to burn for at least 4 minutes (assuming an expenditure of almost 2400 m/s to Jool). This is ignoring the effect of staging and increasing TWR with fuel-losses of course, but in reality the TWR of NERVA upper-stages is also likely to be quite a bit lower... + Let's say your craft is of such mass as to have a TWR of 0.25 around Kerbin with a single LV-N (NERVA) engine. To raise that to 1.5 would take MORE than 6 LV-N's- as each additional engine adds a not-insignificant mass to the vessel. Additionally, each additional LV-N also reduces your available Delta-V budget for the same reason. + The factor of craft structural stability and design-flexibility also comes into play. To make a reasonably-accurate burn to Duna, you won't need as high a TWR as to make an accurate burn to Jool. This means your craft will be placed under fewer Kerbin-G's of acceleration for the transfer burns if you make the refueling stop at Duna (the aerobraking, on the other hand, might place your craft under quite a few G's- but this step isn't strictly-required), or better yet, Ike (if you can, *ALWAYS* make the refueling stop at Ike, never make the stop at Duna- you will save a lot more Delta-V this way if you can still pull it off with an aerobrake, and especially, if you can't- say if your craft is too flimsy to survive aerobraking...) This gives you more options for craft-design: a craft that doesn't need to pull as many G's, and can get by with less thrust, has a lot more options for its design than one than needs to cram in 6 or 8 LN-N engines... You can even utilize some of the more thrust-anemic, but higher-ISP options than NERVA's this way, especially if you are using mods: for instance KSP-Interstellar's ATTILA engines, or NearFuture pack's HydrogenGas plasmodynamic thrusters (which are basically upsized ion engines that utilize a much less dense reactive propellant in the form of hydrogen gas, rather than Xenon, but benefit from improved ISP *and* TWR as a result- compared to stock ion engines...) + For those of you wondering how you could get a craft into orbit around Kerbin than couldn't survive at least 1 Kerbin-G of acceleration, there are two answers to this question: the first is that even with stock gameplay, you can construct large multi-part vessels through docking in-orbit that are often much more flimsy as a whole than their individual modules. The second answer is that with modded gameplay, certain mods (such as Orbital Construction and Extraplanetary Launchpads) actually allow you to construct spacecraft in-orbit out of parts (resources) that you ultimately hauled from the ground on Kerbin or produced from locally-available resources off-planet. - Finally, it should be obvious to you that there is an upper-limit to the size of your spaceships. This is determined both by the limits of the game itself (i.e. part-count and strain on the physics engine), and by your ability to construct a structurally-sound vessel that isn't so complicated as to cause even you, its designer, to forget how to use it properly. Personally, I use mods like NovaPunch2 and StretchyTanks to scale up the maximum size of my craft (by providing larger-diameter parts, I can build larger vessels with reasonable part-counts), and sometimes I really push the limits of part-count sanity nonetheless; but I still make use of refueling stops to allow me to bring larger vessels to more distant destinations... (in fact, I often utilize refueling around the Mun or even Minmus just to reach Duna with many of my craft designs- usually because of one design constraint or another, such as their ability to act as a high-performance plane on Duna, or a frankly insane 240-ton payload size meant to help me establish a large colony on Duna that I simply couldn't build a big enough rocket to move to Duna without refueling...) (3) In-Situ Resource Utilization: - I'll be brief on this one. It (hopefully) goes without needing too much explanation that it is much lighter, and thus costs a LOT less fuel from Kerbin, to send a craft to another celestial body (such as the Mun or Duna) to produce and refine resources there (such as Kethane, or KSP-Interstellar's ability to perform electrolysis of Muna regoltih for Aluminum and Oxidizer), than it does to simply send all the fuel you need from Kerbin. In order to make use of these resources, you're going to either need to make refueling stops at the production location, or send fuel tankers from the production location to somewhere less out-of-the-way for your interplanetary vessel. Often, you'll make use of a combination of the two- for instance mining regolith on the Mun or Kethane on Duna, and then launching the resources to a fuel depot in orbit- which is the actual vessel your interplanetary ship will dock with and refuel. - With enough mods installed, you can produce resources virtually anywhere. The five most important resource-utilization mods I know of are KSP-Interstellar, Kethane Pack, Karbonite, Extraplanetary Launchpads, and (indirectly) NearFuture mod. KSP-I offers a wide variety of resources in appropriate locations, ranging from Munar regolith to LFO mix (presumed to represent combustible ratios of cryogenically-stored Hydrogen and Oxygen gas) extracted from electrolyzing water from Vall's (presumed) ice deposits. Kethane offers, well, Kethane- wihch can be refined directly into LFO, Monopropellent, and even Xenon. Karbonite does pretty much the same thing, but with a different (slightly better) system. Extraplanetary Launchpads offers a three-step resource system in which you mine Ore, then refine it into metal, then again into RocketParts, and finally use a craft-construction part on an existing base or vessel to construct additional ships like at the VAB or SPH, except off-world. Finally, there is NearFuture mod. It doesn't directly give you any ISRU capabilities- but its *HUGE* solar panels (ranging as large as the newest, 250 EC/s, "solar blankets") are the only *practical* way to make large-scale use of KSP-Interstellar's beamed microwave-power system to create solar electricity-farms in orbit. - It also goes without saying that In-Situ Resource Utilization is the *ONLY* way you will ever set up sustainable long-term operations on other planets. It simply takes too many fuel tanker launches to send all the fuel you need to do all the things you want to do otherwise- and it's going to get even worse when they introduce in-game economy, and you have to pay for all these fuel tanker launches as well. I especially recommend Extraplanetary Launchpads and Orbital Construction mods for this purpose (please note, Orbital Construction does not provide a way to manufacture RocketParts on its own- you'll need to also install Extraplanetary Launchpads if you want this functionality- and in fact Extraplanetary Launchpads offers its own orbital-construction mechanic that is slowly making Orbital Construction mod obsolete, if not for the much larger RocketParts "warehouse" modules it offers...) Regards, Northstar P.S. As always, reputation points are appreciated if you found this thread helpful. You can award it using the little star symbol in the lower-left corner... EDIT: Updated explanation to include mention of Karbonite mod as a possible ISRU solution

Actually, it takes over 4k Delta-V to get to Kerbin orbit. It takes 2k delta-V just to reach orbital velocity, but more than twice that thanks to drag and gravity-losses. It takes 600 Delta-V to make it from low Duna orbit to Kerbin, and even less from Ike, the Mun, or Minmus- so yes, if fuel consumption was all you were worried about, it would be a LOT more efficient to produce fuel on one of the moons of Kerbin or Duna, and ship it to low Kerbin orbit, than it would be to launch it from Kerbin. Of course, it still takes more than 1000 Delta-V to make it to orbit from Duna's surface... (drag from its atmosphere limits optimal TWR for ascent, thereby incurring gravity-losses as well as drag-losses) Considering I've spent most of my past 2-3 months launching ships towards the Duna system to undertake a massive colonization effort there (you can see the Mission Reports thread HERE: http://forum.kerbalspaceprogram.com/threads/57509-Kerbin-and-Beyond-a-Maturing-Space-Program ), it'll be interesting to see if I can profit from launching fuel tankers BACK to Kerbin from Ike when the economy is released in a future update... Regards, Northstar

There is a wide spectrum to the term "experienced player", and different players have different skill-sets and specialties. Speaking from the perspective of an experienced player who does a LOT of refueling, gravity-assists, and aerobraking; all to save fuel and Delta-V, let me try and clear this up for you. TECHNICALLY, it costs more Delta-V to do a refueling stop, and then continue on your way to your destination, than just to make a straight transfer, all other things being equal- but there are several EXTREMELY important exceptions to this that can make it a lot more worthwhile: (1) You can save a lot of fuel if the body you make your refueling stop around has an atmosphere. This may not seem intuitive, but aero-"braking" can actually be used to ACCELERATE your ship towards your destination. Let me explain this: -Take the example of Duna, for instance. If you set up a fuel depot in low orbit around Duna, and send a spacecraft from low-altitude orbit around Kerbin to Duna via a low-energy transfer; Duna will be traveling a lot FASTER relative to the Sun than your spacecraft by the time it gets that far away from the Sun... Now, when you enter Duna's SOI, you will have a large velocity difference, and appear to be traveling very "fast" relative to the planet- but from the point of reference of the Sun, it is actually DUNA that is traveling very fast relative to YOU. If you dip into the atmosphere around Duna, it will exert acceleration on your spacecraft to bring it closer to Duna's speed. In essence, you are performing an aero-boost, so to speak, relative to your final target Jool. - Now, if you got your fuel into Duna orbit in the same way (low-energy transfer and aerocapture) you will have saved quite a bit of fuel, as it is approximately 900 less Delta-V to make an ideal transfer to Duna than to make an ideal transfer to Jool (this ISN'T counting fuel-savings from a Munar gravity assist- which will save you close to the same amount of Delta-V on either trip if you perform it right). Now, it does cost approximately 1350 Delta-V to make a transfer from Duna to Jool- but you can make up quite a bit of that extra 450 Delta-V with a gravity-assist from Ike. Additionally, you can make a MUCH more precise burn from Duna than from Kerbin (the burn-time will be shorter), which will more than make up the rest of that Delta-V in terms of reduced steering losses and less need for course corrections if you are using NERVA engines... Of course, this is where (2) comes in... - For BONUS fuel-savings, don't perform an aerocapture to Duna orbit- perform one to Ike. It's a bit tricky to pull off, but if you set you aerobrake such that your exit trajectory comes out with an apoapsis appropriately-oriented to Ike, you can perform an easy capture there, and save a lot more Delta-V then from capturing to Duna orbit- as it takes less Delta-V to make it from Ike orbit to Jool if you make appropriate use of the Oberth effect... (see below) (2) Craft design and the Oberth Effect: - Getting an accurate transfer burn to Jool from low Kerbin orbit is hard. More likely than not, you will need to perform a long, slow burn around Kerbin; followed by a shorter adjustment burn somewhere in interstellar space (MechJeb can help you find the optimal location for these adjustment burns, to minimize Delta-V costs. You could theoretically determine this yourself, but the mathematical equations required are nothing to sneeze at, and it will take a LONG time to locate the optimal adjustment points if you utilize trial-and-error course-plotting instead...) The fact is, the shorter a burn you have to make to get somewhere from Kerbin, the more accurate it is likely to be- simply by virtue of gravity having less time to curve you off-course during your transfer-burn. Additionally, there is something important you need to know about called the "Oberth Effect"... - The Oberth Effect is a mathematical phenomenon that is EXTREMELY important to orbital mechanics. Without going into too much detail about it, you should know the basic result of it: the faster you are going when you burn your engines, the more energy you get out of it. What this basically means, in game-terms, is that it takes less Delta-V to get somewhere from a departure-point where you are already moving fast than in does to get there when you start out moving slowly: even less so than you might think. For this reason, you cannot simply find the difference between your current velocity and the velocity you need to be going at when you arrive at your destination to calculate Delta-V costs. The larger the Delta-V of a transfer burn from planetary orbit, the relatively less Delta-V it costs you relative to the final total kinetic and potential energy you will have at your final destination. If you make a transfer burn from low above Kerbin, it costs you less Delta-V than if you first raise your orbit to the edge of Kerbin's SOI, and then make the transfer from there. It is actually for this reason that an ideal straight transfer (with no steering-losses: though such burns are, in practice, impossible) to Jool from Kerbin theoretically costs you less than a burn to Duna and then from there to Jool, assuming you didn't make use of Duna's atmosphere to provide you with a portion of your velocity. However, the Oberth Effect leads to one other important point you need to know about in order to understand why refueling at Duna can actually make sense: + Due to the way the Oberth effect works, the higher your Thrust-to-Weight Ratio (TWR) is when you make a transfer burn, the less Delta-V it is going to cost you. This is actually for a rather simple reason, really- if your TWR is much lower, your burn will be much longer, and you will make a greater portion of it in a more distant orbit from the celestial body you are departing. This means that your average distance from the body you were orbiting was larger during the burn, and your orbital velocity was lower (the further you are from a body, the lower your orbital velocity). Put another way, you have already lost a portion of you velocity from the beginning of your burn to gravity by the time you are nearing the end of your burn. I don't know how to explain this better- the greater your TWR, the less Delta-V you will spend reaching your destina, even before you account for the greater steering-losses that a lower TWR also inevitably entails... + For obvious reasons (Duna's gravity is less than 1/3 Kerbin's), the same exact craft will have a much greater TWR around Duna than around Kerbin. What this means is, you will come a LOT closer to the idealized transfer to 1350 Delta-V from low Duna orbit to Jool's SOI than you will to the idealized transfer of 1915 Delta-V from low Kerbin orbit to Jool. Put simply, when you combine this with reduced steering-losses it's not 1915 Delta-v vs. 1060 + 1315 Delta-V (idealized transfers), it's more often 2700 Delta-V vs. 1250 + 1400 Delta-V. Just from this fact alone you will save Delta-V with the same craft design, even before you account for the additional gravity-assist that Ike offers you the opportunity to make (from Duna orbit), or the opportunity to aerobrake directly into an Ike-intecept, and refuel around Ike rather than around Duna, which will make your Delta-V savings even greater... - I mentioned craft design earlier, and this is really another important factor to consider. In order to make a reasonably-accurate burn to another planetary system, you generally want to keep your burn-times to no more than 5-6 minutes (shorter if your departure orbit around Kerbin is REALLY low- I usually depart from at least 100 km or higher in order to make my transfer burns more accurate, and give my ships a little more breathing room to make rendezvous with fuel tankers or space stations for fuel, and sometimes crew, transfers before departure). Consider the following: + A craft with a TWR of 1 around Kerbin can accelerate at a little under 10 m/s^2. To make a transfer to Duna at that TWR would take a little over 2 minutes (assuming an expenditure of 1200 m/s Delta-V with steering-losses). For the same craft to make a transfer to Jool it would have to burn for at least 4 minutes (assuming an expenditure of almost 24000 m/s to Jool). This is ignoring the effect of staging and increasing TWR with fuel-losses of course, but in reality the TWR of NERVA upper-stages is also likely to be quite a bit lower... + Let's say your craft is of such mass as to have a TWR of 0.25 around Kerbin with a single LV-N (NERVA) engine. To raise that to 1.5 would take MORE than 6 LV-N's- as each additional engine adds a not-insignificant mass to the vessel. Additionally, each additional LV-N also reduces your available Delta-V budget for the same reason. + The factor of craft structural stability and design-felxibility also comes into play. To make a reasonably-accurate burn to Duna, you won't need as high a TWR as to make an accurate burn to Jool. This means your craft will be placed under fewer Kerbin-G's of acceleration for the transfer burns if you make the refueling stop at Duna (the aerobraking, on the other hand, might place your craft under quite a few G's- but step isn't strictly-required), or better yet, Ike (if you can, *ALWAYS* make the refueling stop at Ike, never make the stop at Duna- you will save a lot more Delta-V this way if you can still pull it off with an aerobrake, and especially, if you can't- say if your craft is too flimsy to survive aerobraking...) This gives you more options for craft-design: a craft that doesn't need to pull as many G's, and can get by with less thrust, has a lot more options for its design than one than needs to cram in 6 or 8 LN-N engines... You can even utilize some of the more thrust-anemic, but higher-ISP options than NERVA's this way, especially if you are using mods: for instance KSP-Interstellar's ATTILA engines, or NearFuture pack's HydrogenGas plasmodynamic thrusters (which are basically upsized ion engines that utilize a much less dense reactive propellant in the form of hydrogen gas, rather than Xenon, but benefit from improved ISP *and* TWR as a result- compared to stock ion engines...) - Finally, it should be obvious to you that there is an upper-limit to the size of your spaceships. This is determined both by the limits of the game itself (i.e. part-count and strain on the physics engine), and by your ability to construct a structurally-sound vessel that isn't so complicated as to cause even you, its designer, to forget how to use it properly. Personally, I use mods like NovaPunch2 and StretchyTanks to scale up the maximum size of my craft (by providing larger-diameter parts, I can build larger vessels with reasonable part-counts), and sometimes I really push the limits of part-count sanity nonetheless; but I still make use of refueling stops to allow me to bring larger vessels to more distant destinations... (in fact, I often utilize refueling around the Mun or even Minmus just to reach Duna with many of my craft designs- usually because of one design constraint or another, such as their ability to act as a high-performance plane on Duna, or a frankly insane 240-ton payload size meant to help me establish a large colony on Duna that I simply couldn't build a big enough rocket to move to Duna without refueling...) (3) Last, but not least, In-Situ Resource Utilization - I'll be brief on this one. It (hopefully) goes without needing too much explanation that it is much lighter, and thus costs a LOT less fuel from Kerbin, to send a craft to another celestial body (such as the Mun or Duna) to produce and refine resources there (such as Kethane, or KSP-Interstellar's ability to perform electrolysis of Muna regoltih for Aluminum and Oxidizer), than it does to simply send all the fuel you need from Kerbin. In order to make use of these resources, you're going to either need to make refueling stops at the production location, or send fuel tankers from the production location to somewhere less out-of-the-way for your interplanetary vessel. Often, you'll make use of a combination of the two- for instance mining regolith on the Mun or Kethane on Duna, and then launching the resources to a fuel depot in orbit- which is the actual vessel your interplanetary ship will dock with and refuel. - With enough mods installed, you can produce resources virtually anywhere. The four most important resource-utilization mods I know of are KSP-Interstellar, Kethane Pack, Extraplanetary Launchpads, and (indirectly) NearFuture mod. KSP-I offers a wide variety of resources in appropriate locations, ranging from Munar regolith to LFO mix (presumed to represent combustible ratios of cryogenically-stored Hydrogen and Oxygen gas) extracted from electrolyzing water from Vall's (presumed) ice deposits. Kethane offers, well, Kethane- wihch can be refined directly into LFO, Monopropellent, and even Xenon. Extraplanetary Launchpads offers a three-step resource system in which you mine Ore, then refine it into metal, then again into RocketParts, and finally use a craft-construction part on an existing base or vessel to construct additional ships like at the VAB or SPH, except off-world. Finally, there is NearFuture mod. It doesn't directly five you an ISRU capabilities- but its *HUGE* solar panels (ranging as large as the newest, 250 EC/s, "solar blankets") are the only *practical* way to make large-scale use of KSP-Interstellar's beamed microwave-power system to create solar electricity-farms in orbit. - It also goes without saying that In-Situ Resource Utilization is the *ONLY* way you will ever set up sustainable long-term operations on other planets. It simply takes too many fuel tanker launches to send all the fuel you need to do all the things you want to do otherwise- and it's going to get even worse when they introduce in-game economy, and you have to pay for all these fuel tanker launches as well. I especially recommend Extraplanetary Launchpads and Orbital Construction mods for this purpose (please note, Orbital Construction does not provide a way to manufacture RocketParts on its own- you'll need to also install Extraplanetary Launchpads if you want this functionality- and in fact Extraplanetary Launchpads offers its own orbital-construction mechanic that is slowly making Orbital Construction mod obsolete, if not for the much larger RocketParts storage/transport modules it offers...) I hope all this helps. I've gone on at great length- and I think I'm even going to post this in its own thread as an aid for new players. Regards, Northstar

So, my experiments with VTOL planes have been going pretty well. Here's a test-flight of what I'm still referring to at the Experimental VTOL Mk2 scouting around the mountains where the HELO B crashed before- I haven't yet given here a proper name: She handles like a beauty in her current form- though this led me to become a little cocky and attempt a very tricky maneuver I accidentally discovered she can pull off where she literally flips around in-flight to face retrograde, and burns her engines to slow down (useful for VTOL landing). It didn't work so well that time though- the flip went fine, but for some reason she was unstable flying in reverse (I know, right? ), and ended up developing a spin I couldn't control and crashing into the mountainside... A revert later (it was all a "simulation") I'm ready to give her a proper name and see if I can't pull off a proper VTOL landing there being more careful... Regards, Northstar

True, the stock aerodynamics model multiplies the drag coefficient (determined by angle of attack with wing parts) by mass- but actually, HEAVIER wings produce more lift in stock aerodynamics- as the stock system also uses mass as an approximation of wing area... This seems counter-intuitive, and in fact doesn't make realistic sense- but basically in stock gameplay your wings would produce the most lift if they were made of lead... (if you could get engines powerful enough to move them quickly) Some mods already include wings with fuel in them. The Firespitter mod WWII-era fighter planes in particular come to mind... Now, in other new- I can't seem to get the CF34 engines to mount on anything (I never tried using them before- so I didn't notice). Is there some special requirement about how they have to be mounted in R4.0c? Regards, Northstar EDIT: Ahh, I remembered, after consulting the configs- actually, I encountered this once before- the ONLY part it will attach to is the B9 medium engine pylons. Its attachment rules don't allow for surface attachments, and it doesn't have any stack nodes, so this ends up being literally the only way to connect it to anything...

By the way- I know this particular thing isn't technically one of the challenge requirements; but I thought it might be interesting to see I actually found real, non-challenge uses for the HELO: B. Namely, attempting to deliver a launchpad to the mountains west of KSC (to save fuel on future rocket launches) Sorry the images are so dark: this mission was performed somewhat after midnight in Kerbal (and real-life) time: Too bad attempting to fly it without MechJeb's built-in altimeter functionality resulted in losing the payload by crashing it into the mountainside (TWICE- the panels from the bottom of the thing fell off in the first crash, and can be see in the background) when I couldn't see how far it was to the ground: I'd install a plugin giving night vision view (like LAZOR)- but my computer is already overburdened with the # of mods I'm running... Regards, Northstar

Interesting design- if you see this Darren, how did you get the blades to tilt? Did you use Infernal Robotics? I tried installing that mod- but it was the straw that broke the camel's back- it was just one mod too many for my computer to handle on top of everything else. Also, I feel the need to point out that Darren also, like me, understood the Egginton Award (no third g in the spelling) to mean 400 kh/h, like the historical record and the challenge originally stated- his pics show his chopper moving at 215.5 m/s, which comes out to roughly 774 km/h- the top speed he stated he reached. Anyways, I have need of a high-speed scout aircraft that can land on a mountainside in my career game (helicopters, especially with the restrictions placed on electrics here, do NOT count as high-speed), so I'm going to go take a look at the VTOL challenge... Regards, Northstar

OK, so attempting an important airlift like this at night without any lights was a major mistake... At first things seemed to be going well, if slowly: Until I managed to crash into the side of the mountaintop the first time, knocking off all the structural panels (hey, they have an impact tolerance of 80 m/s- apparently they did some good!) And then come down too fast a second time when I kept switching between a zoomed-out view and close-up view, trying to see how far down the ground was (a radar altimeter or night-vision would have been REALLY nice here, if only there was an IVA view for the Mk5 cockpit from B9... OH WAIT, I could have just used MechJeb's built-in altimeter functionality in "Surface Info"- darn!) I'm *REALLY* annoyed with this- that airlift took between 90 and 120 minutes with FPS slowdown (and no time-warp), only to result in nothing... I'll have wait until just before dawn and try it again (the morning light is the best time to see terrain contrast). In the meantime, I think I might take a faster, more maneuverable scout plane I can use time-warp on, and see if I can't plant a flag on a good landing spot, so it'll be easier to find if I start my airlift too far before dawn... (it was about 2 AM game time when I get in near the mountains- about the same time it is here in real life- aka. time for me to sleep soon). Regards, Northstar

For those of you who didn't take my advice, and go look at the HELO Challenge thread; one of the craft I designed for it was the HELO (High Electricity Large Ornithopter) Model B- the big one in the teaser pictures before. And, still wanting to build that mountain base I talked about before, I decided it was the perfect craft for the job. So, I decided to first launch a copy of the HELO: B, and move it off the runway, and then build an Extraplanetary Launchpads launchpad, and hook it up... Turned out to be harder than I thought- as the winch and connector port were both a little too high for the Kerbal to reach (I wish I had at least thought to lower the winch end a meter or two when trying to grab it in the first place...) But after quite a few tries at having the Kerbal jump and grab the winch or connect the adapter at the same time, I finally managed to get the helicopter connected to the launchpad. Then came the fun part- trying to get the launchpad into a stable flight regimen. At first, I tried extending the winch to its maximum length, positioning the helicopter directly over the launchpad, and lifting straight up. Once I got the launchpad vertical (not that hard actually) the challenging part was trying to fly with it. But I soon discovered the asymmetric mass-loading from having the cargo bays on each side of the Center of Mass (earlier designs had a single external winch directly beneath the Center of Mass, but I soon discovered that its clearance was too low- and if the landing legs clipped even a little into the ground it would tend to fall off...) consistently caused the chopper to crash: I bet those Kerbals are glad I choose a cockpit with high impact-tolerance right now (and the ones at the KSC glad I only took the 3 Kerbals along necessary to fill the cockpit- the 4th Kerbal I recovered after attaching the winch, as he couldn't make it back on top of the chopper to the passenger hatch under Kerbin gravity). Then I tried something a little different- dragging the launchpad off the runway so I could launch another payload (Rocketparts for the launchpad) of equal mass and hook that up to the other cargo bay... Dragging the launchpad eventually worked (not shown: the several times the structural panels fell off, or even the entire launchpad exploded from a slight bump- even though it has high impact tolerance. Thank God for F5/F9...) However, then I had the brilliant idea- why not try hooking up the launchpad by BOTH its radial connector ports (placed in 2x symmetry) first, to see if that worked... And... the cable didn't reach to the other side- but that's alright, I probably couldn't have gotten my Kerbal on top of the thing to reach the other radial port anyways, and would have had to flip the thing over to make a 2nd connection. This way, I just hooked the launchpad with two cables at very close to the same point- still ensuring a more or less equal distribution of tension in both the cables equidistant on each side of the Center of Mass... (thus avoiding any net-torque) So... the result was: SUCCESS! Well, sort of. I did lose two of the structural panels in one of my first attempts pulling the launchpad off the ground- but I manged to get it off the ground intact in a later try... NOW, comes the equally daunting task of safely hauling this bulky (if relatively light- only a bit over 5 tons in all) thing up to a good spot high in the mountains near the KSC, and setting it down safely... Regards, Northstar P.S. Some of you might have noticed that I have the launchpad much closer to the body of the helicopter in the last picture than when I was lifting it. That was no accident. I was experiencing severe pendulum-like motion with the cables out at 50 meters, and I had to shorten them both in so that the launchpad wouldn't be capable of gaining nearly as much angular momentum.

For those of you curious what my latest side-project has been in the mission dead-time, I suggest you check out the HELO Challenge thread: http://forum.kerbalspaceprogram.com/threads/66633-The-HELO-challenge Here's a teaser- THESE are images I took of craft I designed in it: Now go and view that thread, instead of making me re-post all the progress I made in the challenge here! http://forum.kerbalspaceprogram.com/threads/66633-The-HELO-challenge Regards, Northstar

All went smoothly, and I believe I now have every right to collect the Kolochenko Award- putting my one step closer to the Da Vinci... The dropoff went without a hitch: And, on the return trip, I pushed the HELO:B, and by connection all wingless electric-rotor helicopters (seeing as it has an insanely high TWR) to its limits... The landing went smoothly as well. The observant among you might have noticed I included two pictures that examine the thrust of the electric rotors. Their base thrust is 80 kN, and 120 kN on full Cargo Throttle- like I had them in those screenshots. However, due to rotors having very velocity curves, their thrust tends to fall off very quickly when reaching high speeds- as is clearly demonstrated here, where the thrust is quite a bit greater at the *higher* altitude due to the somewhat lower craft velocity. It's for this reason that circumnavigating Kerbin in 6 hours (requiring an AVERAGE speed of 175 m/s) is *absolutely impossible* for an electric helicopter without either including vertical wings in the design and tipping the craft over so it flies like a plane; or utilizing jet, thermal turbojet, rocket, or ion/plasmodynamic/ATILA engines (all essentially versions of the ion engine concept- listed in order of increasing thrust). The design doesn't have room for sufficiently large vertical wings (I tried finding a good place for them)- so I'm either going to have to spam a ton of small wing pieces (which have less lift relative to their mass), or get a rules change to allow some kind of non-propeller engine... Perhaps an allowance could be made for use fission-powered thermal turbojets- which have rather anemic thrust, extremely high mass relative to that thrust (over 2 tons for about 40-60 kN, with a reduced nuclear fuel load, including the weight of both a reactor and a TTJ nozzle) and burn no fuel? (they rely on reactor heat instead) I already have a place for one on the back of the helicopter (the reactor is in the perfect position- I need only slap on a TTJ nozzle and an air intake- though the turbojet nozzle would compete with my electric generator for reactor output...) Their main (only) advantage for me over props would be their superior altitude and velocity curves (they behave similarly to stock turbojets in terms of ISP and thrust with speed and altitude), which would allow me to mount a nozzle (like I said, it would use the existing reactor) on the back of my helicopter, and perhaps some small horizontal winglets for control/stability and a bit of lift, and be able to probably hit speeds of about 200-250 m/s (enough to circumnavigate Kerbin in under 6 hours). And, to repeat myself- if I added only 1 nozzle, it would simply be fully utilizing the existing reactor- passing air over it to make use of the leftover ThermalPower that the generator doesn't need... And no fuel would be consumed, in fact nothing would be consumed but spare reactor heat- so technically the rules allow it, if you read jets to mean the standard (fuel-burning jets) and gasses to mean what they were obviously targeted at: Xenon, and perhaps also ArgonGas and HydrogenGas resources in NearFuture mod and Argon in KSP-Interstellar... I think it's fair enough that if I'm expected to circumnavigate the globe more than 3 times faster than the real-life world record holder did in a helicopter, I should at least be able to pass a little hot air over my reactor? Otherwise, minus basically cheating and turning your helicopter into a VTOL propeller plane (adding vertical wings, and switching to a horizontal flight regimen after takeoff), there's no physically possible way to build a helicopter that can fly fast enough without massively spamming the smaller (and much higher-TWR) electric plane propellers as a a sort of smaller and more efficient helicopter rotor... Regards, Northstar P.S. When I say MASSIVELY spamming, I mean *MASSIVELY*. My 'Hornet' design, which weighed in at just over 2 tons, and had a maximum TWR in excess of 10 with Cargo Throttle engaged, had 4 of them, and still couldn't sustain 175 m/s in level flight, only in a dive... The HELO:B weighs a bit over 30.5 tons- so you do the math...

OK, so I made a little light modification to the HELO: Model B, and switched the two 6m Structural Fuselages for 6m Cargo Bays. Here she is lifting off the runway with just over 40 tons of metal canisters: The cargo bays are exactly the same length, diameter, weight and weight distribution, and drag- so they change the base performance in no way- and I've decided to make this the permanent base design to avoid the hassle of ever needing to do it again. And, here the HELO: Model B is on approach to the runway with the 40-ton cargo. I believe I've beat the Earth record for highest altitude lifting a 40-ton cargo as well (2,255 m) By quite a lot... Regards, Northstar

Thanks! I'm glad you've been enjoying it! At the moment, I just finished some mod updates/additions. It looks like my CPU is pushed to its limit running this many mods though. Already, I;m experiencing some serious slowdown at the main KSC screen and in R&D. Installing Infernal Robotics and Boat Parts might've been a mistake. Just to make it a little more manageable, I went and deleted all the Firespitter biplane parts, and Boat Parts submarine parts- since I plan on never building any WWI-style biplanes or modern nuclear missile subs... I'll probably be weeding out most of the WWII-era Firespitter parts as well- really all I want from the Firespitter mod is the helicopter and plane rotors, and a few of the landing gears... Don't be surprised if my rate of progress is a little slowed while I deal with the lag situation. I'm going to try looking into the memory fix mod out there that supposedly reduces the CPU usage loading the stock parts... Regards, Northstar EDIT: OK, so, the BoatParts mod was lagging my game too much, and I couldn't get the pre-designed aircraft carrier to load for some reason (I might have accidentally deleted a file needed for it when clearing out the submarine files). So, I decided to clear it out- as well as Infernal Robotics. I simply have too many mods installed, and can't afford any more memory usage... I am keeping Ferram's join reinforcement plugin though- I'm sick of decouplers basically being made of rubber, and engines freely and unrealistically sliding around under my heavier rockets unless I strut them like mad (and sometimes even then...)

No worries man. It's not like you NEED to post, although it's certainly always nice to hear from you. By the way, coming up next: updates, updates, an mo' mods! I've decided to add BoatParts for the aircraft carrier parts and designs it offers- after trying unsuccessfully to build one of my own out of mostly NovaPunch2 and B9 Aerospace parts (no pics, sorry)... The part-counts on my own design were getting horrendous (74 parts- at least 40 of them struts, and it still kept falling apart before it even made it to water- and all for a tiny carrier design that would be very lucky not to capsize if a small 8-ton helicopter landed on it...) I've also decided to try out Infernal Robotics, and Ferram's Kerbal Joint Reinforcement...

Well keep at it man! We'd all love to see another entry on the front page, and your deign was pretty cool! Also, consider installing NearFuture mod. It adds much larger inline battery parts that scale much like the stock batteries. It will drastically cut down on your part-count (maybe allowing you to add additional wing area- your current design would fly higher on Duna with lower wing load) without increasing mass, for the same amount of electrical storage. NearFuture nuclear reactors would also produce electricity more reliably than your solar panels, for lower part-count and less CPU usage; and in the long-run, for less mass than needing to carry a bunch of Kethane to burn for electricity, and tons of batteries to buffer out your power supply... And if you scale up your electrical generation a bit (and run additional/larger props to make use of it) they also benefit from greater electrical generation per ton with the larger reactors... Regards, Northstar

Hardly any of my stations or ships are ever over 70 parts (most are less than 60). So it's not part-count. This is a well-known issue, and there is even a "fix" for it explained by the devs, though it creates invisible water as a side-effect...

Also, err, you can specify that Kerbals need to do it is m/s instead of km/h, but you ought not to re-write Earth history... Scott Kasprowicz circled the Earth at an average speed of 38 m/s (136.7 km/h), not 136.7 m/s- and saying otherwise is incorrect. You ought to clarify that *HE* did it at an average speed of 38 m/s (or 136.7 km/h), but *YOU* expect players to do it at 136.7 m/s... (once again, a 7:25 difference in speed) By the way, if you see this before leaving town or whatever- am I allowed to add small wings as a "minor" modification? That is physically the only way to achieve speeds over about 150-160 m/s with an all-electric helicopter using the Electric Helicopter blades (unless you literally vertically spam them until the point where something like 80-90% of vessel weight is in blades- but that feels like an exploit)... You saw how many rotors the HELO: B had relative to its size- its TWR st sea-level is around 7.5 or 8 or with Cargo Throttle, and the rotors make up more than 40% of vessel-mass, and yet its top sustainable speed is only around 135 m/s, and it physically can't fly faster than 150-154 m/s (for the record, doubling the TWR won't double the top-speed- it'll increase it maybe 40-50%, since helicopter rotors work best near sea-level, where you get a lot of drag- which increases exponentially, eventually forcing you to fly higher-up, where rotors have much lower TWR...) I COULD do it with jets, or I could do it with wings- the issue that must be overcome is a helicopter rotor's velocity-curve (which is so limited as to make achieving an 175 m/s circumnavigation with electric rotors alone impossible). Wings have no velocity-curve, in fact they work better at higher speeds. Jets have a much more favorable velocity-curve than propellers and rotors (in fact, props/rotors use basically the same velocity curve- which is why I used props as smaller, better-TWR rotors on my 'Hornet' design- as smaller rotors/props generally get better TWR due to the way angular momentum and lift works- that is, the bigger the rotor, the exponentially more energy you need to maintain the same tip blade-speed, and lift increases exponentially with tip blade-speed...) I could also do it with roughly 72 of the larger electric plane propellers (incorporating additional attachment mass to the estimate) mounted vertically on the HELO: B instead of Electric Helicopter rotors (of which, it currently has 22), so that I'm basically just using a lot more small rotors instead of fewer big ones, for the smaller rotors' greatly improved TWR- but that would create a lag machine of death that would, frankly, fly at like 2-3 FPS or even crash my computer... Regards, Northstar P.S. For those curious how the 'Hornet' achieved 240 m/s, but conventional electric helicopters can't, there were 3 reasons: (1) It utilized jet plane propellers mounted vertically instead of much lower-TWR helicopter rotors. Basically, just smaller, and thus more mass-efficient, rotors. (2) It had a small rocket on the rear. That only provided 0.4 kN of thrust- but that would be the equivalent of 2-3 kN of thrust with my much larger HELO: B, and it was subject to no velocity-curve. (3) Most importantly, it had significant wing area relative to its mass. Those wings were oriented such as to push it further down in a dive, keeping the helicopter low to the ground where props work best even when the props were throttled up to insane TWR (more than 10). Even so, the wings were oriented such as to work best in a dive, and its speed of 240 m/s was in a dive- it could only sustain MAYBE 160-170 m/s in sustained 60-70 degree flight... (wings mounted closer to perpendicular to the rotors work much better for level flight at angles of attack more than 20 degrees below the horizon- but it was designed for the much thinner atmosphere of Duna, where any angle of attack more than 12-15 degrees below the horizon would produce insufficient vertical "thrust" to avoid a crash...)

Believe it or not, I actually read to OP to mean what it said. Parts in the Kerbal universe are higher-thrust at times, but not by that large of a difference: the difference between m/s and km/h is roughly 7:25, that is, a craft flying 7 m/s is flying 25 km/h. And I can tell you, Kerbal parts DO NOT produce more than 3x the thrust of their real-life counterparts, and DO often have less ISP than irl... (meaning a given Delta-V requires a larger fuel tank, or powering a given # of electric rotors a larger reactor. You think nuclear reactors are OP'd now- see them if the rotors required even 10 or 20% less electricity per kN thrust...) Anyways, sorry again for getting edgy before... I tried to do all these challenges in one play session- and seriously needed a break... Regards, Northstar

WAIT, so if I'm reading you correctly, are you saying that modifications wouldn't DQ the craft from the Da Vinci award? More importantly, I think you need to also take a look at your criteria for "The Kasprowicz Distinction". As it happens, 136.7 km/h is only about 38 m/s. To circumnavigate Kerbin at that speed would take 27.56 hours, not 6 hours. 6 hours means an average speed of 174.53 m/s for the whole flight, which, frankly, is impossible with electric-only craft (if jets are banned). And, it equates to an average speed of 628.32 km/h- more than three and a half times (3.60 to be precise) the average speed that Kasprowicz circumnavigated the Earth... It *APPEARS* that you got the records off Wikipedia (you list almost exactly the same records, in a similar order, and even have a Da Vinci image straight off the page), but made the MAJOR mistake of confusing km/h with m/s. They're two entirely different units of speed- and as I said, some of the distinctions are nearly impossible with m/s... Regards, Northstar

And the Church Award: this took longer than I thought- the HELO B barely makes it... The Award says 400.87 km/h, not m/s. Units are important! 400.87 km/h equates to 111.35 m/s- much different than 400 m/s! (which would be, frankly, impossible without jet engines) The historical speed record, set by John Trevor Egginton, is 400.87 km/h, so you did have it right in the OP: http://en.wikipedia.org/wiki/Helicopter That means, I won the Egginton Award fair and square... Regards, Northstar P.S. Sorry if I'm getting a little edgy- I don't like being deprived of MechJeb for long/slow flights- which I find insanely boring... P.P.S. The "fly-anywhere" capability was kind of the reason I chose electrics. The HELO A won't do me much good off-planet due to its limited lifting capacity and stability problems, but the HELO B would make an excellent heavy-lifter on Duna...