James_Eh

Disagree - during the last stages of ascent (even in upper atmosphere with a bit of drag) you can easily increase your vertical velocity with a TWR under 1. In fact that's a very efficient way to go about finishing off the orbit. It's that magical point where your AP stops rising but your PE zooms upwards.

I'd think that might be the disqualifier here...

Having beaten myself silly proving that the maths seem to be correct regarding Eve SSTOs, I am proposing a new challenge. I have scrolled back through challenges started since the last few updates and haven't seen anything similar so I hope this interests at least a few folks. Build a stock rocket. No fancy jet engines, no fancy ions. No fancy staging. (To be clear - liquid-fuel powered SSTO.) Establish LKO. Report your remaining dV. Really, that's it. What fun! No tedious waiting for your ion glider to run out of sun! No laborious spaceplane ascents! KSP to the core!!!! Note - let's just state up front that this is for unmanned rockets only, although if somebody wants to stick anything other than a lightweight pod onto the craft, feel free... Obviously, pix of crafts in LKO will be required, or videos, or whatnot. OTHER RESTRICTIONS: - no control surfaces of any kind (don't want any issues with infini-glide) - no other obvious cheating with other k-drives, infinite fuel, etc - wings are allowed unless somebody tells me why this is a bad idea - as far as mods go, I'm thinking there need to be two categories for FAR/no FAR. Aside from that, it would be very helpful if you had either MJ or KER to show the dV in the display, otherwise your remaining dV will have to be calculated by hand. Other mods which don't offer any performance improvements to stock parts (and don't introduce better parts) are fine. I have personally been surprised by how much oomph you can wind up with in LKO with a well-designed and flown SSTO rocket. I hope others point the way to even better results! (PS - I firmly believe that this is not simply a spreadsheet exercise. There are things you can do during ascent re: engine thrust balances which can dramatically improve your results.) (leaderboards to be posted here)

Wow. I have perfected a technique that gets a SSTO rocket (no wings, no control surfaces, no ions, no air-breathers) into an 80X80 LKO orbit with 3600 m/s dV left. But despite the fact that I think I can do better, I can't improve upon that. I figure it's not even worth testing on Eve until it is over 5 km/s. This is awesome. Talk about a challenge that will take up even more time than the Jool-5... And the best part is, it's only a few minutes from one test to another. Also, has there ever been a challenge about max dV at LKO (insert altitude here) stock only, chem + LV-N only? Should I make one up? Seems like a reasonable progression from the discussions here.

Glad to hear that my standard method of moving from Laythe to Vall (which invariably involves a stand-on-the-brakes burn) is only partially a result of my bad piloting...

I started building a baseball stadium on Duna. The outfield bleachers were eerily reminiscent of the roof of your cathedral above (nice work, that!) Where I died of boredom was using rovers armed with i-beams for the foul lines. Needed SO MANY of them!!! Maybe I overlooked a way to drop most of it down in one piece? (Substitute your favorite sport...)

Oh and BTW, the first example I gave was just the first thing I slapped together. No more skippers in the design, just those 3.75m single engines plus LV'N's plus wings. Lots and lots of wings. (Absolutely no control surfaces though, don't need 'em and don't want to muddy the purple water more than I already will when I careen into the Evian ocean.)

Taking the liberty of paraphrasing - "Let's see how many rockets this dunderhead strews into the purple sands of death!" Challenge accepted! (Mmph, first challenge is I have never used HyperEdit before... Why is this thing near Eeloo? I clicked Eve dammit...)

Yah, but by the time you reach a few thousand meters it is already out-ISPing everything else, just it is way too heavy to use as a primary lifter due to its thrust limitation.

Hmph. So - can I extrapolate this discussion to figure out what the max dV available at 100x100 LKO would be for a purely liquid-fuelled vessel? (No air-breathers, no ions.) I had always figured that making orbit with a ship like this was nearly impossible, then the 23.5 parts came along, and now I am sitting as above at 3.5km/s dV. But I am beginning to believe that to boost that up to, say, 5.5, is impossible, despite the wings I have started to add and the fooling around with my ascent profile. My spreadsheet resolutely refuses to help me figure out whether the wings are hurting or helping, I am resorting to empirical testing...

Just so I'm absolutely clear here, because I've been fooling around on Kerbin with interesting results: - slap a skipper onto an orange tank (plus the minimum other stuff) and you have something with 5300 dV and plenty of thrust to reach orbit - slap a pair of LV'Ns onto an orange tank and you have something with 12000 dV and enough thrust to slightly cushion the blow as you fall from the launch clamps to the pad - slap all 3 on, and let them all run, and you run out of fuel before reaching orbit (if you just activate the LV-Ns you have 9740 dV but again not remotely enough thrust to go anywhere but down into the irradiated ground) - however: slap all 3 on and manually reduce the skipper's thrust as you head up, so that you maximize the amount of contribution by the 800 ISP LV-Ns, and you wind up in orbit with a pile of dV left By continuously shifting downwards the contribution of the less efficient engines to the ascent, and ultimately running from just LV-Ns (a much larger setup than the above would be required), could you pull it off? From a practical point of view I have no idea how you would throttle down a pile of engines one by one without spinning out of control... Or is this approach negated by the pure math discussion above?

Hoo, boy - I hope you don't think I was criticizing about the use of MJ. You'll note that I let MJ try Tylo something like 20 times before I gave up and did it myself, having learned from MJ. Best of luck on your improvements, my only meaningful advice is STAY AWAY FROM THE DEMON TYLO. (Oh, and bring some boosters along.) And as far as the crazy skillz that some folks have... well, yah. I have been trying to learn how to drop to Eve as a starting point to go everywhere. That's what all the cool guys do. Thus far I have demonstrated fairly conclusively that if you DON'T know what you are doing, you can go somewhere that you don't want to REALLY FAST...

Great fun! I love gigantic Jool-5 ships. (None of this 9 ton Grand Tour nonsense.) I feel your Tylo pain. I truly do.

MJ does very well with vessels where you only use action groups - as I toggle engines (or groups thereof) on/off it changes the dV display accordingly. However where it stops working (and this is certainly no fault of its own) is when you have fuel stowed away in such a way that it can't be pulled by the currently active engines - it figures out the dV based on the assumption that you will drain all fuel available via fuel lines, and then assumes that you will crank up the remaining engines to use up whatever fuel is left. At least that's how I think it works. It can't make the intuitive leap that you are going to manually transfer fuel from tanks that are currently inaccessible by the activated engines.

Sigh. I've spent a couple of hundred of game hours on this exact quest, with the plane heading up towards 100T and counting, only to see these beautiful creations on display. It is often humbling when you see what others have built. Cheers to all of you talented folks! I'm heading back to the lumbering mess of a ship that is about to aerobrake at Laythe.

But I am. 130T or so fully laden. And yes it's unlocked. Just have to fight the urge to overcorrect when we start to slide one way or the other.

Yah, the one thing I have learned is keep the wheels tucked in just a bit so that they don't strike the two spikes of death at the end of the runway. (But not TOO far, else you veer one way or the other on your runway acceleration.) Anyway, Ritier is safely off to Jool, now I want to fiddle with a smaller plane and the suggestions above about optimizing the ramjet performance. I've always viewed that as a derivative of everything else I am doing, not as a control variable. I feel a bunch of backflips into the VAB coming up.

There are two teeny fuel tanks not visible in this picture on the underside of the "plane" which only serve the purpose of providing a halfway point for fuel lines because they wouldn't reach as far as I needed them to. (There are an identical pair visible in this screenshot, just inside the LV-N's. Well, you can only see one of then actually, and then just barely.) They are full of fuel and I suspect are only feeding the rams - that's why the MJ calculator has decided to split up the dV calcs. Usually there is only one line showing total dV and it changes dramatically depending upon which engines you have engaged. It's too late for an easy test because I have begun to refuel after a rather eventful docking procedure. Thanks for not commenting on the... slapdash design.

I have to try the suggestions above. With a smaller craft methinks. Meanwhile: Heading to the Fuel Depot. Here be the vehicle in question. This is basically what I wound up with in 100x100. Note the MJ confusion regarding dV. I am happy that it generated some discussion, though.

After the visit to the fuel depot, Gus is off to Laythe. He likes to live on the edge. I kind of sort of think we might be able to squeak out a return to Kerbal without refuelling again. And if not, well, there are hitchhiker cans in orbit around Laythe left over from my Jool-5 mission that he can hang out in for a while.

Although the mystery is solved, I have to answer this by saying you should come over and watch me fly a spaceplane some day. (WDDAASSQEQEQEQQQEESSSAAAAWWWWWWWWWW!!!!!WW!!!!WW!!!! <crash>) - and so forth

Phooey. It's a MJ reporting issue. I got all excited when I executed a 100 m/s burn and the total dV available only dropped by 100 - thought I had hit the jackpot. Then I started transferring fuel around and noticed the remaining dV as reported by MJ was changing dramatically. Despite the fact that only the two LV-N's are activated, it is obviously assuming (based on fuel flow I would wager) that at some point the ramjets will need to be included in the picture. Ah well. Off to the fuel depot. (Red Iron - nope not even - at 100x100KM orbit: 59.44T total mass, 18.2T fuel. I should have cranked those numbers through my spreadsheet myself, it sure seemed fishy...) Another spaceplane dream ruined. Gotta love this "game".

Now that's a thought, although I'm pretty sure that only the two LV-Ns were lit up in the staging list. Will double check and post orbital pix when I get home.

Well, OK, except in there I had a real question. Should I have posted it somewhere else? Too much background? I was hoping for help.

So... I have spent the last 2+ months watching my giant spaceplanes which were designed to be SSTL (without any refueling stops) get to altitude hdeath (where hdeath = 20,000m + the square root of the log of the effort that I put into improvement of the design) before careening into oblivion. I must have killed poor Gus 100 times. Today I caved and decided that it was morally OK to stop in at a gas station in LKO and refuel the beastie before heading out to Laythe. So I spent, dunno, 10 minutes (?), building a massive fueling station in the VAB, launched it, wound up with about 3 SSTL's worth of fuel (yes, that is a unit, look it up) in orbit with plenty of docking bits and such for easy refueling. 0.23.5 parts make that a breeze. Flipped back to Gus (one has to wonder why he keeps climbing into these things) on the runway, realized that I should oughta put some kind of docking port thingy onto the front of the plane (plus some mono and those wee RCS things), so I went back to the SPH, moved a couple of bits around, and headed out. I figured while I was at it, I would try to optimize my ascent path a bit more. So I spent a little bit more effort than usual keeping my pitch balanced by moving fuel around. Upshot - here I am in 100 km LKO with 8000 dV left, prior to the visit to the refueling station. Best I ever got out of this kludge previously was 3000 dV at LKO, and I made the craft a bit heavier with the changes. dV is measured assuming that I don't use the Skipper any more, nor the rams. (What? You think Skippers are crazy for spaceplanes? I scoff at you.) The space station beckons, but I'm pretty close to what I was aiming for dV-wise.. Am thinking of just heading out. Thoughts? Seriously, can slight adjustments to your ascent path gain 4000+ dV?!?!? (Pure stock except MJ BTW, no FAR which I hear I oughta use...) Do I have to post a picture? It's kind of embarrassing. Not overly... picturesque. How about you look at my previous posts and extrapolate?