PPR

Heaven help us. It's back.

I had intended to just cover air-breathing aircraft, but if you have some guidelines for SSTO's, go for it! As for the heat dissipation, I'm talking about speeds in the neighborhood of Mach 4.5 Personally, I've always liked the aircraft design principle advocated by real-life pilots: "Does it look sexy standing still?"

I learned a lot from my recent forum post of Guidelines for Space Stations and thought I might transition into another area. Since airplanes have long been one of the more difficult designs in KSP, it seemed a natural choice. So let's develop some guidelines for building an airplane. But let me make clear the purpose of this discussion. This is not meant to be a tutorial on plane design. There are plenty of YouTube videos out there that do a wonderful job explaining how build a plane (especially those by Scott Manley). The purpose is to develop guidelines to optimize an airplane design. op·ti·mize verb make the best or most effective use of (a situation, opportunity, or resource). So what do you do to make your plane the best it can be? Because airplanes may be designed to do different things, I would ask posters to state what they intend their guideline to help a plane do. For example, a plane designed for speed would look very different from an airplane designed for high altitude. If you share an example of your design, please include the usual info: mods, part count, speed, altitude, endurance, etc... While I am not exactly a noob when it comes to plane design in KSP, I must admit I spend most of my time with rockets and probes, so it is not a personal strength. But I'll try to get things started with a few guidelines of my own. For high speed: 1) Keep your thrust-to-weight ratio high. 2) Your aircraft will generate a lot of heat from friction, so you will need to include parts that radiate large amounts of heat (engines, wings, pre-coolers, and radiator panels). If you want to know how well a part cools, look in the .cfg file for " emissiveConstant = 0.95" 3) Small wings = less drag. 4) Make sure your parts have a high temperature tolerance (internal & external)

Just being a little OCD on my part. I suppose if a correction is needed, one could use a re-supply or crew vessel to make corrections. I often keep my stations in low orbit 75km to minimize the size of the launch vehicles, so if one docks on the underside or prograde side, you can lower the periapsis into dangerous areas over time. I can see you point however. It makes sense. RCS does have a low ISP, so mass-wise it is not very efficient and part-count wise they are parts you do not need.

I'm curious about this one Warzouz. It has been my experience that after multiple dockings, the orbit of the station tends to shift slightly and requires some sort of propulsion to make corrections. I can see the advantage in terms of mass, cost and part count. What has your experience been using this?

I like to use the mod HotSpot, which gives you a good idea of where the heat comes from and goes. https://github.com/Apokee/HotSpot/releases

I'm seeing some beautiful stations on this thread and would love to see more. Remember, the point of this thread is figuring out ways to build a better station, so please let everyone know what you were planning to do and how well it worked. In addition to mass and mods, I would ask the posters to include the part count as well as any issues with performance or functionality.

I've used the static panels to reduce atmospheric heating for high-speed aircraft. This may seem an odd choice, but there is a logic to it. If you look in the .cfg file for a part, you will see a value called "emissiveConstant". This is a value less than 1.0 which tells how quickly a part gets rid of heat. Parts that have good values (.9 to .95) include: engines, wings, the pre-cooler, and radiators. So why choose a radiator when a wing will provide the same function and provide lift as well? The panels tend to have less mass than the other parts mentioned, which keeps the thrust-to-weight ratio high and allows for high speed travel in atmospheric flight. I've managed sustained flight over long distances at a speeds of mach 4.5+. The other bonus is that the radiator panels don't impact lift, so you can attach them to the specific part that is in danger of overheating. For example, cockpits don't naturally radiate heat and can have a low maximum internal temperature. If that part overheats, you lose everything. You could attach wings to the part, but that might throw off the center of lift. You might attach a pre-cooler, but that might throw off the center of mass. Since the radiator doesn't impact lift and has a smaller mass than other parts, it has little impact on the balance between center of mass and center of lift. They do slightly increase drag, but I've found it a worthwhile trade-off.

Some more guidelines: As worir4 mentioned, too many lights will quickly kill your frame rate. I've found you can usually get away with 4 lights (front/back/top/bottom) as long as they are well placed. When you build the station, try it out on the launch pad at night and see how it looks at night before you launch it. Another thing you may have noticed, spaceships and stations tend to tumble around a N/S pole axis. This makes it hard to dock unless the station's docking port is also along a N/S pole axis. This way the docking port is always facing the same direction.

This topic is to develop guidelines for optimizing a space station. I would like to limit it to stock parts, since mods can easily change the rules that will apply. So what makes your space station work well? Some guidelines I like to follow: 1) Keep the part count as low as possible. This has more to do with performance than gameplay. This is just to avoid performance lag as you dock new parts/ships. Keep this in mind as you add parts such as strut connectors, batteries fuel tanks, ladders & solar panels. They all add up. As rule of thumb go for the largest part you can manage. For example, one Z-4K battery bank has the same capacity/mass as 10 Z-400 batteries but in a single part. 2) Keep the heavy stuff in the middle. You have no doubt by now noticed that if you have a large station and dock something massive at far end it will flex so much that the station becomes difficult to control. The farther you get from the center of mass the more the wobble will be magnified. So if you have a central hub with six nodes it is better to dock six modules to the hub than to stack them on top of each other to form a lengthy chain. 3) Keep it balanced Same idea. If you have something heavy on one side and something light on the opposite side, it makes the station difficult to control. 4) Keep one source of torque in the middle. If you have more than one source of torque (remember, most command parts will have built-in torque), they can fight each other and create wobble. The farther it is from the middle, the more wobble it will create. Remember that you can disable torque if you have more than one source. 5) Don't overbuild. While big stations are impressive, make sure you're building to its purpose. So if you're building an orbital lab, do you need a Convert-o-tron? 6) Pay attention to tolerance You want to have sturdy parts in the middle or an accident could cause the whole station to come apart. For example, an adapter may have a tolerance of 6, while a girder adapter will do the same job but has a tolerance of 80 (and it's cheaper too).

I saved memory using all three startup parameters. OpenGL saved the most memory, but DX11 looked best. DX9 was on brink of crashing & didn't look good. So I guess it is a value judgement as to whether to use OpenGL or DX11, but DTL is an improvement either way. Thanks Rbray89!

Okay, Lithobraking at 115 m/s with a kerbal surviving? That was amazing!

Just tried it one Eve. Worked even better. The airbrakes worked so well I was able to microwave a couple of potato skins while waiting for it to land (and let them cool off enough to eat). The Airbrakes did heat up in the upper atmosphere enough for me to worry, but nothing was destroyed. Only one of the four landing gears was even damaged. Next goal: Duna!

My policy: I will not jettison debris while in a stable orbit around kerbin. Kerbin is too busy to risk a collision (however small the odds may be). As for nukes, you don't have to be that high in the atmosphere for them to become effective. I have no problem with that.

The thing to remember is that the atmosphere slows down your re-entry. When you are going straight down you will only have 70km of atmosphere to slow down. This means you may be travelling too fast for your parachute to deploy. When you de-orbiting at a high surface speed, you are slowing down sideways through hundreds of kilometers of atmosphere. This gives you more time/distance to slow down until your parachute is able to deploy.

For the record: Lithobraking is a landing technique used by unmanned space vehicles to safely reach the surface of a celestial body while reducing landing speed by impact with the body's surface. (Wikipedia) It can use parachutes, rockets, airbags, shock absorbers, or airbraking to reduce speed prior to impact. It applies to bodies with or without atmospheres, which may require different techniques for reducing speed. As for losing the airbrakes, if you deploy them at 70km, they won't break because the atmosphere is too thin, but speed is still reduced. By the time you get deep enough into the atmosphere where heating/pressure would become a problem, your speed has been reduced enough where it isn't. That aside, it actually pretty fun--which is kind of the point of KSP. Like I said, try it.

Try it. It's an interesting option.

After some testing, I've found the airbrakes make lithobraking a real possibility. When de-orbiting, if you deploy air brakes immediately upon entering the atmosphere it reduces the increase in velocity from gravity to the point where heat shields are not needed. While they do not reduce ground impacts to the point where kerbals would survive, with the proper design one can land a probe with no parachutes or engines. The craft I've used have landed at less than 30 m/s & survived. A set of landing gear or a sturdy landing structural will both work. Parachutes may be more useful for a soft landing, but the air brakes have some advantages: 1) Reusable 2) Instant deployment 3) Reduces mass. 4) Deployable at any altitude. 5) Reduces re-entry heating As for disadvantages, they require more parts to work effectively, are bulky, and tend to be more expensive. They don't work well for crewed or heavy craft. But now it's viable a design option. I've only tried it on Kerbin, but I look forward to testing it on Eve.

Amazing work. Thanks Frizzank!

If you look in the .cfg file for a part you will find this: emissiveConstant = 0.95 As I understand it, this is basically a multiplier for how quickly a part gets rid of heat. The higher the number the better. Not every part has this, meaning you need to attach a part that does get rid of the heat, like a wing, engine, or pre-cooler. If you don't the heat gets trapped and builds up until...BOOM!

I wonder if it would be possible to integrate this with Kerbalizer to include some of Scott's most popular quotes.

After two weeks and fifteen pages of comments, I think I'm starting to see a consensus.

I was wondering if there are any changes to Eeloo in the works, given that it is the analog of Pluto and so much new information has been discovered about Pluto in the recent New Horizon mission. For example: the iconic heart-shape, the atmospheric "tail", and the strange moutain-in-crater feature.

Aircraft Specs: Name: Flea Parts: 14 Mass: 3.3 tons Length: 6.4m Wingspan: 3.1 m

The overheating is a product of atmospheric friction. Once you get over Mach 2.5 (~850 m/s) the parts will start to overheat. When you use the basic jet engine this is not a problem because the engine doesn't have enough power to cause trouble. When you use the Turbo ramjet engine, you will start to see problems because the engines grow more powerful at higher speeds. (There are examples of this in real life: when the MiG-25 exceeded about Mach 2.83 it would tend to run away and overheat.) Also, pay close attention to the maximum temperature of the parts. Some parts, like batteries and photovoltaic panels have a maximum temperature of 1200K. A Mk1 cockpit can stand 2000K, a Mk2 2500K and a Mk3 2700K. Once you get above Mach 3, things will start to explode unless you have been very careful in your aircraft design. You want parts that have a high maximum heat, especially the root part. You also want to be able to get rid of the heat quickly. Parts that are good for that are wings, engines, radiators and the engine precooler. With the right construction you can get up to a sustained speed of Mach 4.5. I've even managed an air-breathing jet capable of an apoapsis of over 120km. You can find out more if you read the wiki on the Turbojet.