Lt_Duckweed

Quick question, would having some wings in a bay be against the rules? Basically, be able to open the bay for some extra lift during takeoff, but be able to close them away during cruise to have a lower cruising altitude (depending on the exact craft dynamics a lower cruising altitude can be counter intuitively more efficient). They wouldn't be physically clipped, just located within the bay.

That's exactly what this is about lol. On a lot of my more optimized sstos/planes in general (intended as exercises in theory more so than any practical craft) I am pushing takeoff mass per rapier well north of 40 tons, some even as high as 50+. I ramp up the hills to the west, then accelerate down the hills and across the flats before climbing onto the runway from the side at a very shallow angle, then take off at the end of the runway much like any "normal" plane would. This allows for very high fuel fractions and thus very high dv.

Removing the node via module manager will do nothing to reduce the drag. Drag in ksp is calculated off of "drag cubes" which have surface area and "pointiness" factors for each of 6 different faces. Each node on a part is assigned to one of the 6 faces. Drag cubes can only ever be modified by node attatchment, NOT by deleting a node in the part deffinition. When you node attach two parts, the drag cube faces tied to each node are compared. The ways this can turn out are: 1. The smaller face (by surface area) is removed entirely. The larger face has the surface area of the smaller face subtracted from it, and it's pointiness factor adjusted to reflect the shape of the surface area still exposed. 2. If the two faces are exactly the same size, both get removed. 3. If they are close in size, but don't quite match, its a bit inconsistent but sometimes the pointiness of the larger face gets set to 0, making it infinitely pointy, and thus effectively removed.

Question, one of the rules mentions that you must take off from the runway. But it mentions nothing about the takeoff run needing to be entirely on the runway or not. So my question is: as long as I spawn on the runway, and my wheels leave the ground for powered flight on the runway, does the location of my craft between these two events matter?

For cargo bay occlusion, ksp does not care about where you attached the part, only that it is physically inside the bay. You can attach parts anywhere on a craft and offset them into a bay and the bay will shield them.

I'm fairly certain this s a visual UI only bug. Stratz and I saw something very similar with our Jool craft, where the blades still had drag listed in their part windows, even though the bay was closed. But it was purely visual, the blades were actually producing no drag, but when you closed the bay it didn't update the UI correctly.

Most of your other points were already responded to, but I wanted to address this one specifically. Stock does NOT simulate the effect of wing camber in any way. I have tested this many times and looked through the .cfg files to boot. Lift in stock is exclusively AoA based.

Honestly, boot up a sandbox save and spend a few hours salivating over all the new engines.

Yeah it took a few attempts to get the ascent profile dialed in. Too shallow and you can't make orbit. Too steep and you can't make orbit. It's gotta be just right.

I would like to steal the Minimalist Record from tseitsei89, nearly 4 years after he claimed it, with "Tiny SSTO". Due to the nature of a minimalist challenge, it has the exact same parts as "SpecialSpeckOfDust", arranged in a different manner. With some careful design considerations I was able to reliably shave ~100 m/s off of the ascent on a craft to craft consideration. Namely, the strut was attached to the rear node of the spark to reduce drag and offset to its position as a landing skid, and the wing is angled 5 degrees to provide better l/d ratio through the early parts of the flight when drag is highest. However, rather than removing all 100m/s worth of fuel, I have opted to simply reduce the mass as compared to the previous record by 1kg, to a new value of 835kg.

This right here x100. I did the math and at sea level at mach .9 (which is where backface drag peaks before starting to drop off again) you are losing something like 7% of a rapier's thrust to it's own backface drag.

Landed!

Managed to reach 1686.2m/s at 21.86km. Craft does NOT want to take off easily and I had less than half of a kn of spare thrust leaving the runway, but it could, so there is probably room for optimization by reducing wing area and taking off from the flats around the ksc rather than the runway itself. EDIT: Woops, forgot to land it, let me do that real quick.

I don't have the craft file of the edit available right now, but I do have the file for the ssto it is based on: https://kerbalx.com/Lt_Duckweed/Nuclear-Grace And here's an album about it: https://m.imgur.com/gallery/fTWS13F Keep in mind that it is NOT easy to fly if you aren't already a pretty skilled plane pilot. To upgrade it for 3.2x scale it needs about half the payload mass replaced with liquid fuel, and double the number of nervs. It's already at the limit of what can make it off the runway, so if you add any mass to it it needs to take off from the flats around the ksc instead (which there is plenty of at 3.2x scale)

I would highly recommend using the fan blades instead of props. They have higher top speed, more thrust, and are more compact. Also, this is Eve we are talking about. It is punishing. Unforgiving. Cruel. Forget the rover, forget the solar panels, forget the large isru, forget the docking port. Eve does not give you the luxury of having luxuries. The last time I made an Eve ssto it was 180 tons, and had a payload to low Eve orbit of 3 tons of liquid fuel. Eve is HARD, there are probably less than 2 dozen players who have made successful Eve ssto's

So I was curious, so I swapped to 1.9.1 and installed the needed mods for a 3.2 rescale. I then made a quick and dirty edit to my orange tank lifter. Namely, I added an extra pair of Nervs to the front of my existing nerv stack, then rotated half the stack so they faced backwards. Then I permitted pulling liquid fuel from the payload tank. Starting mass is 78.587 tons, mass in orbit is 45.617 tons. Payload mass is 21.950 tons (because I pulled fuel from the tank, I need to subtract the dry mass of the percentage of the tank I used to get the true payload) This gives me 32.97 tons of liquid fuel (well a smidgen of ox is mixed into that number because I forgot to set the rapiers to manual switching) burned to get 21.950 tons to orbit. This gives me about 240 funds per ton to orbit, only counting fuel costs. Obviously the overall cost will depend on how accurate you can get with runway landings. Payload fraction on this is 27.9%, so a bit better than I predicted, but this is a fairly optimal case, so I would expect a practical design using a fairing to land solidly in the middle of my predicted 20-25% range.

I would argue that this is a case where you would prefer the stock system over FAR, as you enjoy substantially higher high supersonic and hypersonic lift to drag ratios in stock. With a decent understanding of stock aero, it is easily possible to enjoy a 4+ lift to drag ratio from about mach 1.5 to well past mach 5, with a peak a bit past mach 2, without needing to resort to any weird aero exploits. When using weird aero exploits it is possible to push this to close to 5, possibly a bit past 5. As far as I am aware FAR planes do not enjoy anywhere near this l/d ratio at these high mach numbers. Conceptually, this isn't that hard to design for. You need about 2km/s more dv and probably something like double the twr in the nuclear phase of flight, and while there may need to be some design changes depending on the heat settings, not a whole lot else changes. Ballparking it here, but I would expect payload fraction would drop by a factor of 2.5 or so, so something like 20-25%.

The approach that I took was to get the explicit equation for an ellipse with one foci at (0, 0), then perform 3 integrals 1. The integral for the ellipse from c-a to n (where n is the x coordinate point we are interested in) 2. The line radiating out from the origin to the point in interest expressed with slope as a function of n, then integrated from 0 to n 3. The ellipse integrated from n to c+a. After much variable wrangling and simplification, I got to the equation n= a*sin((c/a)(1-((n-c)/a)^2)^(1/2))+c where n is the x coord of the point, a is the semimajor axis, and c is the distance from the foci to the center of the ellipse (in other words a*eccentricity). I'm sure you can see the issue here. while I have a nice clean n by itself on the left, I also have one buried deep within the sin term on the right.

Yeah, that's way better than the integrals I was doing in rectangular coordinates lol.

For funsies, I decided to take a stab at this and uhh, it's not pretty at all...

Right, duh, brain fart on my part.

Because I use a built in 5 degrees of incidence on virtually all my planes, I have this same behavior of a tendency to climb. However, rather than using elevators to inhibit rate of climb by utilizing negative lift me big dumb, I do so by decreasing angle on my canards, thereby decreasing positive canard lift.

I think this would be quite interesting, perhaps a challenge for lowest fuel/ton/km to various destinations (Island Runway, Desert, Circumnavigation, Multi Circumnavigation) with various weight classes?

In addition to kerbal wind tunnel (which is absolutely fantastic btw), correctCoL (correct center of lift) and rcs build aid are both extremely useful for spaceplane builders. CorrectCoL because it shows the true center of aerodynamic pressure on your ship, and has handy stability charts as well. RCS build aid because it can show wet and dry CoM at the same time, and show you how each fuel type on the craft contributes to CoM shift.

Just as an fyi, that isn't how aero clipping works. It doesn't matter where you originally placed the part, only weather or not the CoM of the part is physically in the bay and the bay is larger than the part it is shielding (ie you can't shield a nerv with a standard 1.25m bay). Same goes for fairings, where you originally placed the part is irrelevant, all that matters is that the CoM be within the fairing (and the aforementioned size restraints).