zolotiyeruki

Nah, versions of this challenge date back at least to 2014:

Does attaching wings to objects inside the fairing mess with the aero or thermal? I seem to remember there being some odd behavior about that.

jinnantonix now leads both of the competitive leaderboards. Y'all aren't going to let that stand, are you? jinnantonix, can you share how you attached your wings? It looks like you have your whole fuselage in a fairing, which would preclude attaching wings in that way.

Wow, that landing had me holding my breath a bit--you nearly stuffed the nose into the dirt. What a ride! I think you could take a few more seconds' credit, since you actually got to 0 m/s.

Grrr, I've been working/tweaking/optimizing my own entry for the Voyager division, and I have a design that I think will take the cake. But the capsule keeps overheating after two and a half hours of Mach 5+ cruising

On the topic of P2P Starship delivering rapid cargo, what if they stuck the cargo in its own re-entry vehicle, and lofted it on a ballistic trajectory with SS? Then SS releases the cargo, and (now unladen) burns to put itself onto a one-around orbit. The cargo reenters to its destination, and SS lands back where it started.

Yes, cosmetic-only mods are fine.

Sounds like the Waddington effect to me. The guy's story is pretty interesting--he and his team looked at how the British were waging war, and pointed out seemingly simple (and sometimes counterintuitive) things that made a big difference. One of their findings was that bombers had the greatest amount of unplanned maintenance (i.e. things broke) right after their 50-hour overhaul, and had fewer and fewer problems the longer they went from the 50-hour maintenance. And they told the RAF that the 50-hour maintenance period was too short and caused more problems than it solved. In essence, what they told the RAF was "if it ain't broke, don't fix it."

Alright, I have a question about the appearance of the rocket exhaust, and could use some education: 1) At launch, what is the composition of all those billowing clouds? Is the rocket kicking up that much dust from around the launch pad? Or is it imperfectly-burned LF/Ox? Or is it a whole lotta condensed water vapor from the exhaust? A combination of the three? Something else? 2) At low altitudes, the exhaust is a bright yellow flame, and then around Max-Q it's more of a transparent orange, and then at MECO, it's almost invisible. Why is that? Is it because the exhaust expands more at higher altitude, so there's not such a concentration of light-emitting hot/burning gasses in the plume?

Yeah, the test craft was about 11 tons and 1 rapier. You'd be dealing with a lot more lift-induced drag with that much mass.

An addendum to the shock cone intake on the rear of the fuselage: I took that slapped-together craft, and tweaked a few things--replaced the probe core with a faired Mk1 capsule, and set the wing incidence to 3 degrees instead of 5. And then I tested it with and without the nose cone on the tail, at two different speeds, 1,650m/s and 1,715m/s, in level flight. For a given speed, both versions of the plane flew within about 100m of the same altitude (slighly lower for the version with the SCI due to the added weight). I ignored max temperature and used infinite fuel and electricity to get to a steady state. At 1,650m/s, total drag was decreased by 4.9% by adding the shock cone intake to the back of the rapier. At 1,715m/s, total drag was decreased by 11.2%. It's interesting to note that, as noted earlier, the lift-induced drag (as reported by the game) is strongly affected by speed--going from 1650 to 1715 resulted in a higher altitude, but also about 10% less lift, as the plane gets closer to orbital velocity.

I can confirm the above--I just did a simple test, and that is 100% true. As for the silliness of banning nose cones on the back of rapiers, in the same simple test, I took a craft and tested it with and without the shock cone intake on the back of the engine. The difference was about 2.2% total drag. Granted, this was a thrown-together design with the wings at a 5 degree angle of incidence, so the wing parasitic drag is higher than you'd use for competition.

Well, you could do the math. Let's say you've got a 50cm vertical jump on earth (because that makes the math easy). 0.5 = 1/2*9.8*t^2, and your fall time is about 1/3 second, and your vertical speed is 1/3*9.8 ~= 3.3m/s. On the moon, with roughly 1.6m/s^2 gravity, your fall time would be about 2 seconds, so you'd make it 1/2*1.6*2^2 ~= 3.2 m off the floor. That's a standing jump, upwards. If you launched at a 45 degree angle, your initial vertical velocity would be .707*3.3 = 2.3m/s, which works out to a fall time of about 1.5 seconds. If we neglect air resistance, you'd fly 1.5s * 2 * 2.3 = 6.9 meters. If you're a bit more athletic, or you get a running start, then yeah, crossing a 9m room in a single bound is within the realm of possibility.

Good enough for 4th place! You're on the board.

I imagine the passive stability enforced by the much larger rear fins would be plenty to minimize the adverse roll effects from the canards.

So you're telling me that you constantly corrected the roll offset for over seven hours!? Or, if you were at 4x time warp, for almost two hours!? Holy smokes man, you're dedicated! (Incidentally, that's why I've taken on the maintenance of Pilot Assistant, so you don't have to do exactly that) Congratulations, you're at the top of the leaderboard. You certainly earned it. Even before 1.10, the engine noises got so irritating that I turn off the sound when running this challenge.

That's a fair point about the yaw/roll coupling, although I wonder how much roll you'd actually get, given the much larger surface area of the (hypothetically fixed) rear fins.

That's an interesting aside. When I've done a mk1-sized craft with a single RAPIER, near the end of the flight, it's only generating a couple kN of thrust to sustain near-1700m/s speeds at 27km altitude. An LV-909 at max thrust will burn 3.5 units/second of fuel, according to the wiki (is that LF only, or combined LF/Ox?), and produce 60kN. If it only needs to produce 5kN, that's 1/12th max thrust, so 3.5/12 ~=0.3 units/second. Two FL-T800's would give you about 800 units total LF/Ox, which would be more than enough for the 40-minute trip, assuming you use a RAPIER to get you up to 1700m/s and 27km. In fact, it's better than that, for two reasons: 1) using a rocket engine would allow you to fly at 29,900m and encounter significantly less parasitic drag 2) higher altitude and velocity means you're closer to orbital speed, and you need less lift to maintain altitude. It gets a bit nerdy, but I figured out that the amount of lift you have to provide is proportional to (GM/R^2 - V^2/R). With some hard numbers plugged in, if you're at 1700m/s and 27km, you only have to supply about 48% of the baseline lift, and at 1,900 m/s, you're down to about 36%. Note that the percentage of lift you have to supply doesn't change much with altitude. Actually, thinking about it a bit more, just using a RAPIER in closed cycle mode would probably be better, despite the Isp hit, since you'd eliminate the dead weight and drag of a second engine.

I have a question: Assuming SS is passively stable in the roll axis, why would you need to have actuated rear fins at all? You could control pitch and yaw with just the canards. The best system being no system, and all that...

Remember that only air-breathing engines are allowd

Yeah, making it around once isn't too bad. Making it around many times, or going really fast, is where the challenge lies!

Will do, and thank you for your honesty. Way back when I was participating in the 1.3 or 1.4 version of this challenge, just as a test, I stuck a shock cone intake on the back of a RAPIER, and it resulted in something like a 30% reduction in fuel burn. Crazy stuff.

...and the lower the state of battery charge, the faster it accelerates!

You got to orbit. That's a huge step. The screenshot you posted appears to be setting up a maneuver node. Since you're not familiar with that, it sounds like you're pretty early into your career, and haven't upgraded much. In Career mode, you want to accept contracts to get money (to build rockets and upgrade your buildings) and collect science to unlock more parts. The wiki has a fantastic explanation of how the science system works--basically, do you various experiments and observations in various places, and return them (or transmit them) to collect science. And you spend science on unlocking parts. In terms of mods, there are two that are "must have"s for me: Kerbal Engineer (incredibly useful for lots of things, but especially useful when building rockets to see your TWR and dV of each stage) and Kerbal Alarm Clock (which you probably don't need *yet*, seeing how early you are in the game). I use a few other mods for specific situations (Pilot Assistant) or on more advanced designs (PreciseEditor and RCS Build Aid for planes), but KER and KAC are, to me, indispensable.

Here are a few tips: Of all the nose cones in the game, the Shock Cone Intake has by far the least drag. If you're willing to get a little cheaty, you can stick a Shock Cone on the back of your engines, and then offset them into the engine. That way, you get the reduction of drag, without the nose cone sitting in the way of the exhaust. The game has a default calculation for drag, but some parts override that calculation, via values set in that part's .cfg file. It's also worth noting that there's drag due to the shape, and there's also skin drag. That's why a plane with a Mk1 LF tank can fly perfectly straight and level and still have non-negligible drag from the fuel tank, even if the tank is fully occluded from the airstream. Any time you change fuselage diameter, you'll pay a pretty heavy drag penalty. You may see better results if you stick with Mk3 parts for the entire length of your craft--you'll get more fuel in a shorter craft, and you'll avoid some of the drag penalty from going up and down sizes as much.