GoSlash27

[quote name='Right']Not that it invalidates your point, but that graph would happen even if you were wrong due to decreasing fuel mass and atmospheric drag.[/QUOTE] Right, That's kinda the point. You've got to be careful with car analogies because cars don't work like rockets. A more accurate car analogy would go like this: If you're in a parked car and accelerate to 10 kph into a crowd, you're not going to seriously injure anyone. If, OTOH, you're in a car doing 100 kph and you accelerate to 110, the difference that 10 kph makes is much more catastrophic. the difference is nonlinear and that's what the Oberth effect is about. Best, -Slashy

[quote name='Right']Okay I've got my terminology confused. I'm describing powered gravity assists. Strictly speaking, the Oberth effect has nothing to do with gravity. However, isn't it fair to say that the Oberth effect is not the sole reason periapsis burns are the most effective?[/QUOTE] Right, Actually, I would say that it is *not* fair to say that. In fact, periapsis burns are not necessarily the most effective even with Oberth effect. Without the Oberth effect, it would make more sense to do your burns as far out of the gravity well as possible. As it stands, it makes sense to do your transfers from LKO because that's where you happen to be. It would be more efficient to do your transfer at a higher altitude (depending on where you're going), but it always takes more energy to get up there than it saves. OhioBob did a really good write- up on this a couple months back. Best, -Slashy

[quote name='Rakaydos']I'm interested in caveman restrictions, but I dont have a "complete" caveman file set up. I'm trying to figure out how to set up a core+boosters like some of you use to bypass the mass/part limit, with asparagus staging. (in sandbox) However, the fuel pipes keep taking me over the 30 part limit on the core stage. I figured out an approach that could work, suspending the core stage without a cart, and using two booster carts (with attached boosters) to haul it around. Unfortunately, in sandbox the launchpad has a huge ramp, making retrieval testing impractacle. [URL]http://i.imgur.com/s11ouLe.png[/URL] I'll probably start a cheater-caveman file (testing in sandbox) once my current file unlocks the last few tier 5 science nodes.[/QUOTE] Rakaydos, Yeah... just thinking about this stuff makes my head hurt :D I've never tried to voltron caveman tech to venture to other worlds as others have done here. I've only ever completed the basic caveman requirements for the challenge. My hat (or fuzzbeest pelt as the case may be) is off to any of you who can do that. Best, -Slashy

[quote name='pellinor']quadratic (just nitpicking, of course that does not invalidate your point)[/QUOTE] pellinor, Yeah, you're right. Quadratic. Best, -Slashy

[quote name='Right']As far as I can tell, the explanation fits for retrograde burns just fine. When you slow down at the periapsis, you spend more time in the gravity well subsequently, which serves to slow you down more than otherwise. I could be mistaken, I'll check out your link.[/QUOTE] Right, I'm with RIC on this one. the Oberth effect has nothing to do with gravity wells. It's simply the result of the [s]exponential[/s] [B]quadratic[/B] relationship between velocity and energy. It holds true even without gravity wells. Best, -Slashy

Quasarrgames, 2 things jump out at me off the bat: 1) That's way too much intake area and those intakes aren't clean ones. That's a boatload of drag you don't need. 2) You don't appear to be using wing incidence to generate lift, but rather angle of attack. For problem #1, what other intakes do you have available to play with? For problem #2, using body lift is super- bad for drag. You want the nose pointed exactly prograde around Mach 1, not above it. This gives you the smallest, cleanest profile and allows you to cut through the sound barrier. Once you clear about 360 m/sec, your drag falls off and your thrust picks up. Best, -Slashy

[quote name='Tatonf']Thanks for all the replies, but I still don't understand why I gain more "kinetic energy" from burning in LKO rather than in Sun's orbit. You say that I can't compare my velocity from LKO and the velocity from my Sun orbit, but what does matter at the end ? My velocity relatively to the Sun ? That would mean that, if I go orbiting the Sun at an altitude where my velocity is greater than 9284.5 + 3431.0 = 12 715.5 m/s, the Oberth effect I'll get from the Sun will be better than the one I get from LKO ?[/QUOTE] Tatonf, For interplanetary trajectories, your velocity about the sun *does* matter. When orbiting Kerbin, your speed is added to (or subtracted from) Kerbin's orbit around the sun. If you burn after barely ejecting from Kerbin, you're starting with Kerbin's 9300 m/s velocity. If you burn while in LKO, you're starting with Kerbin's 9300 m/s plus another 2300 m/sec*. An ill-advised car analogy :D If you're in a car doing sixty and you drop a rock out of the window, the rock will be doing sixty. If, OTOH, you're sitting on the same car doing sixty and put the rock in a sling and twirl it, you can throw it much faster. Best, -Slashy *technically the velocities are vector added when crossing SoI boundaries, not linear.

^ This. It will also help if we can see a pic of your spaceplane. Perhaps there's something going on that's making it draggier than it should be. Best, -Slashy

I have noticed that the Mk1 with ablator is a little too aerodynamic to be safe once it slows to subsonic speeds. It just freefalls and has a hard time getting below 250 m/sec. So what I do now is attach the heat shield with a decoupler and jettison it once the danger from heating is passed. Not only does this increase the drag from the capsule, but the jettisoned shield tends to stick in place and slow you even more. You get to safe deployment speed with no problem doing that. Best, -Slashy

Tatonf, What gets you from place to place isn't actually "delta vee", it's "delta kinetic energy". We think of it as a change in [I]velocity[/I] because it simplifies the math. Since kinetic energy is proportional to the square of velocity, we add more kinetic energy with velocity at high speed than we do at low speed. Best, -Slashy

[quote name='Red Iron Crown']Just for fun, compare the cfgs for the existing jet engines in 1.0.4 to the 1.0.5 cfgs for the same engines. :)[/QUOTE] ^ This. The engines do what they did before and now need less intakes to do it. On the down- side, they bumped the Whiplash up to tech level 8, but to make up for that they introduced the Panther at tech level 6. You can make a respectable spaceplane with a Panther if you know your stuff. Best, -Slashy

More power to you and all... but I personally don't see the point of making all the engines balanced. So long as there are no engines that outclass everything else and no engines that are utterly worthless, I consider the differences to be part of the game progression. Streetwind, [quote]the Twin Boar, which includes a fuel tank, and is secretly one of the most mis-statted and overpowered engine in the entire game[/quote] Sorta. It's only really suited to use as a lower stage because it's not stackable, but it's not nearly as cheap as a cluster of Kickbacks. Consider: A single Twin Boar can handle a load of 60 tonnes as a booster (min. 1.4 t/w and 1800 m/sec at 1/2 atm) and costs $26,500. A cluster of 7 Kickbacks can do the same thing for $18,900. Best, -Slashy

[quote name='fisfis'][COLOR=#333333]Good, but if you have to rework everything to be able to continue your career (which is almost impossible with latest version), what do you do then?[/COLOR][/QUOTE] Me personally... I never continue careers through major updates. I start a new career from a clean slate so I can see how the changes affect career progression. If I'm in the middle of something when a new version drops, I finish it before updating. Best, -Slashy

I ran a full- up test of my career "Munreaper" system, which is designed to harvest almost all of the Mun's and Munmus' science efficiently. I ran "Caveman" up to tech level 5, then ran contracts for cash to upgrade the facilities. During the "caveman" portion, I gave my landers the ability to dock so that they would be useful in this setup. Munreaper consists of 4 independent vehicles: MunTanker: Acts as a docking base and fuel supply for the landers. It holds enough fuel for 10 missions. MunarScout: A reusable SSTO surface probe with all the science gadgets. Equipped with an antenna for the early going and a docking port for the later missions. Munar Excursion Vehicle: An SSTO crew lander for manned science, introduced at TL 6. And finally the MunarClipper: A round trip shuttle from KSC to a station in low munar orbit and back. With this setup I should be able to recover all the science from the Mun and Minmus in short order, unlocking the entire tech tree. [img]http://i52.photobucket.com/albums/g13/GoSlash27/Munreaper1_zps3gmdsfdd.jpg[/img] MunarClipper not shown... Best, -Slashy

Absolutely, SSTO spaceplanes are the king of low cost to orbit. The downside is that you have to actively recover it in order to reap the savings and the penalty for failure is high. If you want to orbit payloads for cheap and not spend most of your time recovering the launch vehicle, a 2- stager with a SRB lower is the way to go. It does demand better design skillz to go that way, but for one- off launches it's hard to beat. Best, -Slashy

The only thing constant in KSP is change. Rather than complaining about it, I look at each new release as a learning experience. Figuring out the new wrinkles is a big part of the fun for me. Best, -Slashy

[quote name='royying']Is intake spamming still useful now?[/QUOTE] No, it's not. Intake spamming is counterproductive from 1.0 on. All it does is add drag in exchange for air that you can't use. If engines are fed beyond their useful speed and altitude, they will produce nothing but noise, heat, and *negative* thrust at the expense of fuel. The goal now is to have just enough intakes to keep the engines lit while they are still useful while adding as little drag as possible. Precoolers are the new hotness in 1.05. Best, -Slashy

Jouni, This should only be a problem in early career play, where players are going to design something similar to this and have a limited selection of parts. I'll run another test with the ablator turned down. Best, -Slashy

Another vote for electric props. I'd also like to see hydrogen bags for balloons. Best, -Slashy

The important thing I'm seeing: A simple Mk.1 capsule with 'chute is too clean when equipped with a heat shield. Once it gets subsonic, you have to wait forever for safe deployment of the 'chute. You run the risk of smacking into the ground before the 'chute deploys. I logged a bug report about it. In the meantime, I recommend attaching the heat shield with a decoupler and jettisoning it once the heating subsides. Best, -Slashy

MrOsterman, A Mun rescue vessel doesn't require much when designed properly, but you're new at this so we just have to accept that. Your plan is sound, but there's one important thing to remember: You have a specific place you need to land. Landing in a precise location is hugely wasteful of DV compared to simply landing. [U][B] Therefore you must design your descent stage to have twice the recommended DV.[/B][/U] 1,200 m/sec from Munar orbit to the surface will give you enough leeway to land right on top of her. If this requirement proves insurmountable getting her home, just design something that will get her to orbit. Rescuing somebody from munar orbit is much easier than rescuing them from the surface. Spare no expense and get her home safe! -Slashy

Draconiator, The beauty of playing KSP Caveman- style is that it forces you to operate more efficiently. In doing that, you learn to make the most of what KSP provides. I'm a big fan of simplicity. IMO "perfection" isn't when there's nothing else to add, it's when there's nothing else that can be removed. Best, -Slashy

KerikBalm, Thanks for posting these graphs. I'm sure they'll prove useful. If you get the chance, could you multiply the % sea level thrust by the sea level thrust, convert the density to altitude, and flip the X axis? I bet that'd make it easier for newbies to read. Best, -Slashy

All, My "rescue1" career craft is very nearly killing Kerbals because it's not bleeding off airspeed sufficiently at subsonic speeds. I'm barely getting the 'chute out and deployed by 300m. I suspect the heat shield. To test this, I ran 2 identical reentries at 72km x 45km. Here's the safe chute deployment altitude with the ablator: [IMG]http://i52.photobucket.com/albums/g13/GoSlash27/Chuteshield1_zpsdvfnrzjy.jpg[/IMG] And here it is without: [IMG]http://i52.photobucket.com/albums/g13/GoSlash27/Chutebare1_zpsvhlhzwte.jpg[/IMG] As you can see, the bare capsule decelerates to 250m/sec over 2km higher than the capsule with heat shield. A clean reentry capsule ends up deploying just barely in the nick of time at sea level. I'd recommend increasing the drag coefficient for the ablator to match the capsule. In the meantime, it can be worked around by using a decoupler to detach the heat shield after reentry heating subsides. All of this was done with a stock Windows install and no mods. Best, -Slashy

Nicholander, Congratulations! Glad it worked out for you. FWIW, you're probably not going to be able to max out a RAPIER without overheating and exploding parts on your plane, so you may want to trade some top speed for altitude as you did here. Best, -Slashy