Servo

I made an excavator... without the DLC KerbalX Download: https://kerbalx.com/servo/Excavator

Honestly, I'm still in awe that I managed to get this thing working. For all you curious engineers out there, here's the craft download: https://kerbalx.com/servo/Excavator

Full Stock Excavator Four degrees of freedom, just like the real thing. All hinges utilize bending parts to create hinges and servos I feel like my reputation comes mainly from my stock replica planes, but mechanical builds of all kinds were my first love. Recently, I've been developing a new method of creating stock hinges that we're calling BendyTech. It's kinda a big deal (it even has its own forum thread) To show off the power of this new tech, I decided to make the most ridiculous thing I could think of. So I built an excavator. -------------------------------------------------------------------------------------------------- User Manual Download Link: Download link: https://kerbalx.com/servo/Excavator Controls are as follows: Each of the hinges behaves a little differently, so take a little time getting used to the responsiveness of each. The servo can be rotated fluidly if you time it right, but each of the other joints are somewhat slow to respond, due to the limited actuation speed of the control surfaces. This is only a real problem on the elbow, which can easily clip into the arm. Fortunately, this doesn't break anything, and can easily be reversed. If anything breaks out of its hinge, return each of the arm joints to neutral and then use time warp (if able) to reset the joints. -------------------------------------------------------------------------------------------------- Under the Hood Waist Rotation Originally, when I was first conceptualizing uses of BendyTech, I didn’t imagine that it would be possible to exceed the rotation range of a single part, much less be able to create controlled 360 degree rotation. But, through a clever arrangement of elevons and choreographed toggling of Same Vessel Interaction, each RCS ball can be passed forwards to the next elevon in the ladder, allowing 22.5 degree actuation precision. Adding a second set of RCS balls strengthens the hinge and locks it into a single position, instead of flopping across the 22.5 degree range. Interestingly, this drive abuses the way that KSP’s physics engine calculates bending to allow for unlimited rotation with a finite spring. The core theory of computational structural analysis is Strain Energy Minimization, which tries to find the arrangement of parts which are the least stretched. Once the craft has rotated 360 degrees, there are two possible arrangements for the spring: rotated 360 degrees, and rotated 0 degrees. Because the game doesn’t have code to account for people bending something 360 degrees without breaking it, the physics engine simply takes the less stretched position, and the parts snap into place, ready for another rotation. I wish I could say that I planned for this to happen, but it was just a lucky accident. Video below: Shoulder/Wrist Rotation Each of these joints is the simplest form of bendy tech, using elevons to push smaller parts, similar to what is shown to the right. Each is strengthened by a thermometer hinge, which helps redirect the motion into rotation. Elbow Rotation Another very basic BendyTech technique here, albeit one that abuses a current bug in 1.8/9 where adjusting the Airbrake deploy angle using axis groups can extend it far past the intended limits, in both directions. It’s a cheap, dirty, way to get a large rotation angle in a small package. This element takes full advantage of the single-craft nature of BendyTech, since the best way I found for the airbrake to be set up was attached to the rotating element. Just another way that BendyTech represents a major upgrade over classic stock tech Video Below: Craft Download: https://kerbalx.com/servo/Excavator

Hello from Japan! Mitsubishi's next-generation derivative of the F-16 was quite fun to build, and is even more fun to fly. This is the second craft I've released utilizing BendyTech to its full potential. Here, we have all-moving stabilators which are nigh-indestructible thanks to the tech's reliability. Download from KerbalX: https://kerbalx.com/servo/Mitsubishi-F-2

Aye. The project has been put on a slight hold as I wait to have enough time to be willing to sit down and get it working again. There's a reason that I typically alternate between mechanical and static builds - I love building the complex ones, but man are they draining to perfect. It's time will come, though. This project was my breath of fresh air. I'm rather happy with how well the rest of this came together. Just over 400 parts as it stands currently, though that might change as I go into ... sigh... bugfixing the stabilators

Definitely! I just need to get the darn thing to work consistently I realized after several hours of annoyedness with the various hinges (I was trying to get the servo to be better at supporting weight), that it's actually the wheels which are causing all of the headaches... More work to be done here, but it's slightly frustrating that the glitchy part of this craft isn't the fact that I'm torquing pieces of it around in angles that were never intended to be reached, but the wheels... to take my mind off of things, I continued working on my replica of the Mitsubishi F-2. The vertical stabilizer, ventral fins, wings, and chines are all products of today's effort.

@Castille7 and @klond, I have a new addition to your construction sites: This craft was designed to be the poster child for everything that bendy tech can do - rotate parts, control off of axis groups, and maintain control across different elements, all while still being one craft. Yeah, the DLC exists, but doing it stock is more of an engineering challenge. This is how it started the day - I added the airbrake actuation to the elbow, which has some occasional mishaps with regards to overextension, but otherwise, it works perfectly. The wrist was a very simple joint. It's slow and not particularly high-range of motion, but it gets the job done. Additionally, this shows off another amusing trick of bendy tech - fuel lines bend with the parts, so they make perfect piston analogues.

Improved the servo and made a cleaner video - functions the same, except that by rearranging how the elevons deploy, I have reduced the number of action groups required to just 2 - one to tick it one step, and the other to reverse the direction. Now it leaves only to use the servo somehow. The mechanism is perfectly suited for tank turrets, but that was a little too expected for me... So I'm building an excavator. I'm currently in the mechanical testing stage on the elbow joint, which has been giving me a bit of trouble. The shoulder joint is a very simple RCS/Thermo hinge (you don't need anything fancier 90% of the time), actuated by a single elevon. That elevon is AG'd to forwards/back deploy limit adjust, giving the entire joint a 60 degree range of motion. More would be possible with an airbrake, but that runs into problems with the airbrakes over-deploying when used with the deploy adjust (devs pls fix) Because of the airbrake woes I'm having to try out a series of different joint designs for the elbow here, which needs 90 degree actuation, on a small profile. Unfortunately, those don't mesh too well, so I'm still looking for ideas (up to an including recreating the servo joint to drive this joint. Possible, just not implemented). This is an attempt at doubling the effective deploy of the elevon. I think this has the most promise, but the idea needs a bit more refinement to be proven. Here's another idea that I tried shortly - double stacked elevons. Idea is really simple: one elevon pushes the second elevon, which pushes the target. Unfortunately, due to the fact that joints prefer to translate rather than rotate, this isn't the most useful design without needing a lot of hinges (or one hinge with a bunch of rotators inside it... I've messed with stock hinges that have multiple rotating elements inside a larger hinge, so I could imagine a large Thermo hinge frame packed with thin communotrons all sharing the same hinge frame) If anyone wants to develop any of these ideas further, or has good ideas for how to multiply the rotation of elevons, I'd love to hear about it! I'm genuinely so happy that other people are joining in in my weird pursuit of springs and things, so I'd really like to see what you guys can come up with

I invented a stock BendyTech servo that can rotate continuously in both directions, and function under high-stress loads. So I'm doing what any reasonable person would do given this power: I'm building an excavator. I imagined this craft as both highly detailed and highly functional demonstrator for BendyTech to really push the limits of what's possible with parts pushing each other around. As such, I'm going all-out on the details. This particular curve vexed me for a bit, but I'm incredibly happy with the end result.

Thanks! I'm glad that other people are joining in and pushing the boundaries of the base game I want to thank everyone who's been experimenting with Bendy Tech, and for inspiring me and everyone else. Again, this wasn't the effort of just me by any stretch. It was these guys who saw the potential in my little experiments and shaped it into something useful. With this news, I would like to share another major breakthrough in Bendy Tech that will allow even more complexity in mechanisms than I ever thought possible. Fittingly, I have invented Bendy Tech servo motors The best analogy for how this mechanism works is a marble machine stair lifter like the one below: To step the motor clockwise, you alternate between pressing action groups 1 and 2. This bends the RCS ball ring 45 degrees, and clips it through the second ring (which has SVI disabled). When you hit the other action group, the sequences reverses and moves it another 45 degrees, by enabling the SVI on the second set of elevons and disabling it on the first. Then, the elevons return to their neutral position, which brings the ring of balls forward another step. To reverse the motion, a second pair of action groups is used, which works the same way. Craft Download: https://kerbalx.com/servo/Servos-Servo-Servo

After a failed persuasion roll to not do such a thing, one of my friends has inadvertently convinced me to build a replica of the Mitsubishi F-2, a sort of Super-Viper F-16 derivative used in the Japan Air Self Defense Force. The key to this build for me was the stabilators. If I couldn't get them, it wasn't worth doing. The trouble with making good F-16/F-2 tailplanes kept me from making a high-detail replica for some time, but again, thanks to the wonders of Bendy Tech, we can now create functional control surfaces of all kinds without relying on the parts added in the DLC. Since there aren't many good blueprints of the F-2, I've brought an old technique out of the back room. This sort of framing is very useful if you're working from a three-view and you want to make sure you get the proportions right before you move into real parts.

The shaping on this is fantastic - very innovative use of parts to get the color and everything right

After probably the longest development period of any craft of mine yet, I finally present the Vought F8U Crusader! This thing sat on the shelf in my SPH folder for over a year pending a solution to the unreliable docking of the variable-incidence wing. That solution was Bendy Tech, and it works great! Looks good, flies better: with 2/3rds throttle and full flaps/wing extension, you can goose this thing along at 35m/s. Download it here: https://kerbalx.com/servo/Vought-F8U-Crusader_2

A fine example of BendyTech at work here - providing an extremely simple, yet strong, mechanism to control my F8U Crusader's Variable-incidence wing If you've read through the examples in the original post, the mechanism will be extremely familiar - it's basically copy-pasted from the third example, with the only change being the addition of a guide (a single structural panel sliding between two fixed ones) to prevent roll input from messing up the hinges. It's entirely probably that even that isn't necessary. Another interesting quirk of how Variable-Incidence works is that you can use the grandparent autostrut without it breaking the structure, since the parts matched via symmetry are moving together.

I agree completely, but maybe substituting "ambition" for "skill" - it's so much easier to tackle highly complex builds than it was versions ago, and the support system of other builders encourages people to dream bigger and do one better than has been done before. Personally, I subscribe to the idea that perfection comes when there is nothing left to take away. And while I appreciate 1000+ part count monsters (I certainly wish I had the patience and time to make a few more, myself), you can exhibit skill in smaller builds just as much (if not more so) than it larger ones. Which I suppose brings me to a segue towards my latest project, the Vought F8U Crusader It's a very low-part count replica (as far as 1:1 replicas of mine go), at just over 200 parts, though I definitely wouldn't call it anywhere near perfect. The body shaping is a fair approximation, and there's definitely room to make a much better model (in the 350-400 part range, probably), and I look forwards to seeing how whoever makes that build does it. I was definitely tempted a few times building this to tear it down and completely rebuild it, since the intake isn't shaped quite right, and the cockpit is too rounded at the back, and so on, but I resisted that temptation, since this project wasn't about that. It's about completing a project that vexed me for the better part of a year, before sitting dormant for another one. So in the end, I suppose this is more about accepting that something isn't perfect, and appreciating it for the sole fact that it is completed. Now that I'm done philosophizing, here's the nuts and bolts: This is (probably) the first full craft build released using Bendy Tech to create stock functionality. In this case, the Crusader's 7-degree elevation variable incidence wing. Bendy Tech has the major advantage of not relying on docking ports or separate craft, so small rotations and high-stress applications can be created without losing the control authority that comes with a floating wing (which would have been required for this particular build before the development of Bendy Tech). For more about Bendy Tech, check out the thread I wrote on the topic: All that combines with low wing-loading and high TWR to give the Crusader absolutely insane low-speed performance. You can see it here flying straight and level (kinda) at 35m/s, which I can assure you, is rather fun for a craft that can also push the sound barrier. You could definitely land it on the VAB as-is.

More progress to report on here, I think. Thinking that the wings on this thing were in a somewhat reliable mistake, I decided to spend the time cleaning up the rear of the Aardvark to prepare it for release. Filled in the overwing section, the underside of the aft fuselage, and reworked the bit between the engines, plus the engines themselves. There was some progress made on the wings, but they're still too floppy and unreliable for full release. It's possible that better strutting would fix that, but that still ignores the problem with the engines popping their sockets, which is another problem in and of itself. But at least once those issues are solved the rest of the plane will be ready.... As a diversionary project, I returned to a project that I hadn't touched in well over a year. I was trying to get the variable incidence wing to function with traditional stock hinges and docking ports, but the range of motion was just barely not there. Conveniently, this is a perfect use case for bendy-tech, since the 7 degree actuation is no problem for a system that doesn't have to dock back when it's done. Barring any major problems (fingers crossed) this will be a fairly quick project. In fact, I might even go for bendy-tech elevators just to spice things up while I'm at it.

A lot of progress to report here! @HB Stratos and I spent a lot of time today on this craft, and I finally have positive progress to report This is the most complex build I've ever made, and it comes as a collaboration between HB and myself - the General Dynamics F-111A Aardvark. We've been talking for years about doing a collab build, so it's great that we're actually doing it now. This craft is packed with stock mechanisms, including the swinging wings, custom landing gear, and all-moving stabilators that provide roll control too. The wings and stabilator utilize the BendyTech that HB and I have discovered and developed, using Same Vessel Interaction to bend the wings without the use of docking ports. More info here: Over the course of a hours-long discord call, we were finally able to implement Bendy Tech in a reliable manner, with the biggest headache being the wings (turns out, forcing part of your craft to bend 60 degrees against its will is tough) That's all not to mention the absolutely wonderful set of custom gear HB's built for this thing - it's a miracle that it fits, and it works great.

An Introduction to Bendy Tech Bendy Tech is a new way to make pure stock mechanisms in KSP, combining reliability and simplicity in a simple-to-build way ... The elevator of @Kronus_Aerospace's upcoming 747SP replica utilizing Bendy Tech It's no secret that some builders such as myself, @Phantomic, and @HB Stratos continue building stock mechanics despite the presence of robotic parts from the DLC. Whether it's a desire to make your craft accessible to the largest number of people, desirable properties of stock mechanics, we prefer the challenge of keeping things stock, or just that we're old farts who refuse to believe that our once cutting-edge tech is now outdated, we keep building craft that swing their wings, have oversized control surfaces, or have other functions beyond what is conventionally possible with the pure stock parts. A Stock Innovation born from the DLC The Rigid Attachment and Same Vessel Interaction options in the SPH. The release of the Breaking Ground DLC added the option for easily building gears and other complex mechanisms which were all part of the same craft. With the mechanics of the time, parts could not collide with another part of the same vessel, so the option to toggle Same Vessel Interaction (SVI) was added in the editor. Notably, parts with SVI can only interact with other parts with SVI. If you combine this with "actuators" which have moving colliders (Airbrakes, elevons, tail fins, landing gear, and service bays) to force parts of the same craft to bend - without the use of a servo or hinge from the DLC. To facilitate the bending, chains of weak joints are added between the colliding parts, creating a "spring". This is further facilitated by the use of the Rigid Attachment feature on the actuators, as well as on any "guide" or "hinge" (static parts which either guide or transform the motion). Introduction to Bendy Tech A simple example of BendyTech - a 20 degree swing, useful for an all-moving tailplane This is a very basic example of the principle at work here (fittingly so - it was my first test of the tech's potential). Hidden from view is a stack of six separators connecting the I-beam to the structural panel. The elevators are attached to the structural panels, which sandwich the I-beam. The elevators are set up to respond to yaw controls as pictured (the forwards pair have control authority set to -30, and the backwards ones +30), and have SVI and rigid attach enabled. The I-beam is the only other part with SVI enabled. If you are interested in using this tech yourself, I highly recommend attempting to replicate this setup, as it contains the essential elements of Bendy Tech designs. Two Axis-Control, high-stress applications A more complex mechanism allows for two-axis control, and stronger construction to defeat the inherent bendyness of Bendy Tech The above image shows my first attempt at a practical Bendy Tech mechanism - adding a gimbal to the fixed Reliant engine. While functional, it is less than practical, due to the added size and weight. However, it very clearly shows how the tech can be evolved into more complex applications, while showing some of the limitations. Most notably, the fact that all parts with SVI enabled cannot overlap. The elevons must be arranged in such a way that they can be useful without crossing into each other's control area. A craft download for this craft can be found here: https://kerbalx.com/servo/Engine-with-custom-gimbal-no-DLC For the extremely clever among you, there is a way to minimize the mechanism by rearranging the control inputs and I-beams down to a 1.25m profile. The doing of this is trivial and is left as an exercise to the reader. Or you can see how here: https://kerbalx.com/servo/Gimbal-Assortment Advanced Bendy Tech: Hinges Classic Stock Mechanics make a return in the Bendy Tech hinges. Here, they redirect the lateral displacement of the I-beam into rotation Here is the area where I stop claiming innovations as my own. @HB Stratos was the first to see a way to improve the rotation ability of the tech by adding a simple RCS/Thermometer hinge on either side to stabilize the motion. Importantly, small radial-attach parts do not have the ability to enable SVI by default. However, there are two ways around that: Craft-file Editing (which I will leave to HB to explain in his own post), and action groups. You can set the relevant parts to enable SVI on the stage action group (or whichever AG you use to actuate the parts), and it will function as normal. Another important advanced note here: if you are using hinges, you must use docking ports instead of separators as your spring. Otherwise the hinge will break out of its cage. For an exhausting look at the uses and construction of stock hinges, I recommend a stroll through this thread: Advanced Bendy Tech: Guides Structural panels form the guides for the wings on HB's and my forthcoming F-111 Aardvark replica The use of guides to keep parts in line is old hat to anyone who's built complex mechanisms (DLC or otherwise). Here, the advance is in the size of the guide - with stacked structural panels, you can fit the guide *inside* a single wing panel. This really takes advantage of the fact that Bendy Tech can fit inside of any part, so long as those parts don't have SVI enabled themselves. This eliminates one of the biggest weaknesses of previous stock tech, and I look forwards to seeing how it is abused in the future. Limitations and Advanced Potential of Bendy Tech While Bendy Tech is a new and very interesting development, it's not a perfect solution, so using it effectively is a matter of knowing its strengths and weaknesses. Strengths and Weaknesses of Bendy Tech Strength Weakness Single craft allows control of all elements throughout flight, using standard flight controls bending parts behave poorly under physics warp Using Deploy Adjust action groups, can create fine motion, including motion of less than 1m Limited range of motion, cannot rotate indefinitely Reliable mechanism not relying on docking ports or KLAW adapters Long springs can increase part counts of craft Mechanisms can fit inside of other parts Without support structures such as guides, large parts are floppy under external loads Applications and Inspiration board @Kronus_Aerospace's large elevator. You can see the RCS hinge near the launch clamp. Actuation is provided by a Big-S elevon Flaps and slats - the flexible tech is well-suited to creating complex mechanisms which expand, especially since control is maintained on any elevons along the length of the flap. Our WIP Aardvark, with wing actuation exposed. The wing swings through a 60 degree arc, and the craft also features Bendy Tech all-moving stabilators actuated by tail fins. A Community of Builders Getting Bendy Tech to this stage is not a singular accomplishment, but the combined work of a community of stock replica builders. If you would like to join us, drop me a PM and I'll get you added to our server On behalf of HB_stratos, Kronus_aerospace, and others, I hope you'll join us in pushing the limits of what can be done with the base game

Very cool! That level of automation is extremely impressive

The McDonnell RF-101 Voodoo The RF-101C of the NMUSAF, which took part in Operation Sun Run, the fastest transcontinental flight of its time. This will focus on my replica of the RF-101 reconnaissance variant, rather than the fighter-bomber and interceptor variants (F-101A/C and F-101B, respectively). When I was just a wee lad, my grandfather gave me a book featuring photos and writeups of every aircraft in the National Museum of the U.S. Air Force. Included in the book was the above image, and something about it must have stuck in my mind, since when I began building my first pass at the Century Series, I made sure to build the recon variant rather than any of the other ones. Something about the odd nose shape appealed to me, so I wanted to make sure it was replicated. Here's the result of that little bit of inspiration. This plane has some interesting things going on here, particularly in the nose. The shape of the camera-holding schnozz required the use of long-flat pieces, which resulted in my using the backs of radial ramp intakes, a technique which would come back several times on my builds (including on the undersides of my modern F-100 and F-101 builds). If you need a long, flat section (or one with a slight camber), flipping them works really well. Doubly so if you need the colors to match with wings, or they just need to be a constant color. Moving upwards, the black area is created using the undersides of communotrons was a new thing as near as I can tell. I have no idea why I did it (the color wasn't the reason, so I guess it must have been the shape), but it's a technique that would return often. Pics below: My RF-101C: https://kerbalx.com/servo/RF-101C-Voodoo As promised previously, this plane is a great example of how edge alignment can make a build look smoother than it really is. If nothing else, it makes it look like you put a lot of time into perfecting how your craft will look, which is a good thing. The later craft in the series are all good examples of this too, but since this craft has the most different things going on to align, I figured that I'd go for it here. Plus, I'm impatient. This technique relies on the fact that the structural fusealges, structural wings, and doubled Mk0 tanks are all the same length, meaning that you can create repeating patterns. This means that more of the surface is flat textures, pushing towards the idea of "smooth" crafts. More on that below: Another useful lesson learned from this craft is the use of varied color palettes. This area is what I hope to make an impact in for other builders - using different sets of parts in a continuous fashion to create different colors. I went into a lot more depth here: Or, in short: Light: White fairings, radiators (static) Standard: Jet fuel tanks/Structural fuselages, wings, airbrakes, landing gear, ladders, solar panels (stowable), Inline Clamp-o-trons, air intakes, backs of radial air intakes. RCS balls. The rectangular prism probe core. Blue: Solar panels, gravioli detectors - warning: they are not the same color blue Dark Grey/Back: Backs of small fuel cells, backs of deployable communatrons, ore tanks Medium Grey: Large Fuel Cell backs, solar panel backs, I-beams, atmospheric spectro-variometer backs, structural panels. Small LFO tanks. Thermometer backs. This craft has a couple different palettes in different areas, featuring the black palette on the nose to create the film windows, standard palette on the fuselage and wings, and the medium grey forming the cockpit and engine area. If I were less aggressive about part count, I would have differentiated the cockpit and engines by using a bluer parts on the cockpit.

Oh I love it so. My F-100 replica was a major step forwards for me in terms of build quality and techniques. I think I'll take the next few days going deep on the build techniques I used to create each of these craft, one day at a time. This F-100 was the result of my embracing the power of the Mk0 tank as a fuselage shaping tool. I had used it somewhat in my earlier F/A-18 and Dassault Rafale, but the use in those builds was either more limited or less effective, primarily due to the lack of an effective way of filling in the sides of the fuselage. Thanks to the mostly flat sides of the Super Sabre. There are also several notable uses of landing gear as structural elements rather than functional elements. Landing gear came into their own in early 2018. My memory fails me, but I know that @NorthAmericanAviation had been using landing gear as nose cones since before then, but the earliest use (and likely where I found the technique) of landing gear as something other than a nose cone was @EvenFlow's F-15 in March. Landing gear have a very unique shape which lends them to replicating curved and organic shapes (the latter shown by @EpicSpaceTroll139's Dinosaurs), making them perfect for the tapered bits at the nose. Two other techniques are on full display here, each of which I either developed or perfected in this craft. The most distinctive element of the F-100 (and the one which has vexed so many craft-builders for so long) is the ovular intake on the nose. The use of the communotron here was a flash of insight that I can only attribute to my time spent building small-scale craft (another proof that spending time doing something other than your main thing can lead to new insights). The communotron is a perfect part to use when shaping intakes of all kinds, and it's singlehandedly added 50 parts to every craft that I've made since then. Communotrons are also on display here. For a beautiful example of the sort of work that you can do with communotrons, @Kronus_Aerospace has a beautiful F-104 with intakes painstakingly crafted from communotrons. The second thing here that's present is the Oscar-B tank cockpit. This is EvenFlow's great contribution to stock replica builders everywhere. They're controversial (every time I post a Oscar-B cockpitted plane, there are always comments), but I really do enjoy their sleek look, ease of construction, and and relatively low part count compared to comparable solar panel or gravioli methods). Now, for the old one. Honestly, this one's not as bad as I remembered it. KSP aero updates have actually been rather kind to this little jet. Similarly, my appreciation for this odd little plane's build quality has grown as it aged. It's got a bit of the Mk0 tank work going on on the spine, and even more importantly, there's a gem that I hadn't remembered: the communotron spike on the tail. Seems like I always return back to some things after all. Even the fuselage has its charm - the Radial Ramp intakes create a decent impression of the shaping of the nose, and the Mk0 intakes, while awkward, are about par for the course as far as Super Sabre intakes go. Another fun note that isn't on display as much in the modern F-100 as in my other modern replicas: the stripe on the fuselage continues across multiple parts. Edge alignment is a key element of my modern attempts at "smooth" building (a good example of which is my F/A-18 Hornet, reference the fuselage side.) Perhaps I'll discuss that more as I take a look at the F-101 Voodoo next. This has been a really fun exercise in reflection and analysis for my own purposes, so I hope you enjoy reading it! I'll be back soon with a look at some of the other planes featured here.

The Century Series A dual story of progress and creation The Century Series before the introduction of the F-106 in 1959. Clockwise from upper right, F-105 Thunderchief, F-101 Voodoo, F-102 Delta Dagger, F-100 Super Sabre, and F-104 Starfighter In the early 1950s, the U.S. aircraft manufacturers had taken the lessons learned from the first generation of jet fighters into account when designing a new suite of aircraft for the modern air war. These planes would keep pace with the rapidly advancing technologies of the time, with powerful engines, radars, afterburners, and complex fire-control systems coming into their own for the first time. The North American F-100 Super Sabre was the first U.S. Jet capable of level supersonic flight The second generation of jet fighters for the newly minted United States Air Force would take the naming convention used by the previous subsonic fighters to a new level. The F-100 Super Sabre led off the now-iconic Century Series, which ultimately saw the addition of five other aircraft. Other aircraft shared the naming series, but only the ones discussed here saw any production beyond the prototype phase. They entered service at a key time for the USAF, fighter command as it was expanding its role and reach to include more roles - peacetime interception of enemy bomber patrols, reconnaissance overflights of key targets, and tactical strikes made by fighter aircraft instead of lumbering bombers. The McDonnell RF-101 Voodoo was a reconnaissance platform which made key low-level overflights of missile sites during the Cuban Missile Crisis Another key development during this time period was the development of the doctrine of air-to-air refueling. The Century Series were the first planes equipped to take on fuel during flight, a technology which extended both operational ranges and mission durations, while also increasing mission readiness. This air-to-air refueling was used for a novel purpose in October of 1957, when during Operation Sun Run, a trio of stripped-down RF-101 Voodoos took off from Los Angeles and over the course of the next seven hours flew to New York and back, after a total of 25 air-to-air refuelings across the fleet. The Convair F-102 Delta Dagger was delayed three years due to difficulties in understanding the aerodynamics of transonic flight These new technologies weren't without their troubles, though. The aerodynamics of supersonic and transonic flight were poorly understood in the 1950's. The design of the experimental aircraft which broke the sound barrier were modeled off of 50 caliber bullets, since that shape was the only one known to be stable at supersonic speeds. Early supersonic planes such as the F-101 and the F-100 dealt with the problem of aerodynamics mainly through experimentation rather than theory, and relied on relatively thin wings and perhaps good fortune on the part of the designers. However, when the first F-102 prototype took to the skies, they realized that something was wrong with the design. The supposed Mach 1.5 interceptor couldn't even go supersonic - and it wasn't entirely the engine's fault. Extensive research led to the rediscovery of the Whitcomb Area Rule, the guiding rule for transonic drag on aircraft, and its implementation on the F-102 allowing it to reach much higher speeds. This is responsible for the shock bodies seen on the engine nozzle (modeled here by the landing gear), as well as the characteristic wasp-waist of many of this era's fighters. It is most noticeable on the F-102 and F-106, but it is present on the F-105 as well. The Lockheed F-104 Starfighter looked like something out of fiction, but soon helped turn spaceflight into science fact In the 1950s, as the space race heated up, both the Soviet Union and the United States began looking for candidates to fill the ranks of their astronaut corps. Both found a natural fit in their highly-trained jet fighter pilots, and particularly the subset of test pilots. This would be enough to cement the relationship between the Starfighter and the first spacecraft, but the F-104 had another unique contribution to the space program. The U.S. Air force needed to train its prospective astronauts to navigate out of atmosphere, using RCS thrusters instead of control surfaces, but had no good way of testing the systems in a full-system way. They tapped Kelly Johnson of Skunkworks to develop a testbed for the new technology, and in 1963, the NF-104A made its first flight. This was a modified starfighter equipped with rocket engines to boost the maximum altitude of the F-104 from 50,000 feet to 120,000 feet in high arcing climbs during which the aerodynamic control surfaces of the fighter would become useless and the pilot would use the RCS system to maneuver instead. This testbed worked, and the technology was proven for use in manned spaceflight. The Republic F-105 Thunderchief was a victim of a changing air war, saved only by the development of the SEAD role for the platform Introduced too late for the war in Korea, the first real tests of the series came in the skies over Vietnam. They soon discovered that air war had changed, and not in a way that favored the jet fighter. The proliferation of radar-directed fire control, nimble and hard to hit enemy MiGs, and the newly-proven surface-to-air missile led to loss rates far higher than any in the USAF upper echelons expected. Hit hardest by this changing battlefield was Republic's F-105 Thunderchief. True to its spiritual ancestor, the P-47 Thunderbolt, Republics newest jet fighter was the heaviest single-engine, single-seat fighter ever built. It was designed to carry bomb loads heavier and faster than a B-17, get in, and get out alive. However, the world of agile fighters,and accurate AA fire firing more powerful munitions meant that being tough wasn't a ticket to survivability any more. The F-105 ultimately became the only U.S. aircraft pulled from frontline fighting due to heavy loss rates, and would have been deemed a complete failure were it not for the development of the Suppression of Enemy Air Defenses (SEAD) team. SEADs squadrons, better known as Wild Weasel squadrons, flew the EF-105, which carried advanced electronics monitering and tracking systems, as well as radar-seeking missiles. They would fly ahead of the strike team into defended air space and bait the enemy radar installations into attempting to lock onto their aircraft. Then, they would track the radar signal and direct guided weapons to destroy the air defenses. Fitting for a squadron whose main job is playing chicken with SAMs, their slogan was "You've got to be (screwing) me", reportedly said by the Captain when he was first tole what his mission would be. The Wild Weasel squadrons live on today, now flying highly modified EA-18 Growler. The Convair F-106 Delta Dart was the last dedicated interceptor fielded by the U.S.A.F, showing a shift in the roles of fighters in the Air Force The Century Series tells the story of a developing air force, and a consolidation of the roles played by its fighters. The F-100, F-101A, and F-105 were fighter-bombers which were designed to tangle with enemy fighters and ground units, while the F-101B, F-102, F-104, and F-106 were dedicated straight-line interceptors designed to get somewhere as fast as possible and take out enemy bomber formations. This dichotomy was a holdover from the days of WWII when a variety of aircraft filled different roles. However, the consolidation of the aircraft industry (it took a large company to enter the jet market, so many mergers occurred and smaller companies exited the market) and the rise of the multi-role fighter ended the lines of the dedicated interceptor and the dedicated fighter-bomber. This is immediately evidenced by the fact that in the U.S., only a single plane is considered a Third Generation fighter (the Century Series, among others, make up the Second Generation): The F-4 Phantom II. The fact that a single aircraft could be used across the USAF, USNAF, and USMC in all manner of roles was revolutionary at the time, and echoes the consolidation present today with the Joint Strike Fighter. The Century Series represented a period of extreme technological growth and progress from the fledgling USAF As with the USAF, the Century Series has been a metric of progress for myself as I continue to push the boundaries of what's possible with stock parts My first act as a stock replica builder, three years ago yesterday, was to upload the entirety of the Century Series to KerbalX. They were fair replicas, nothing extremely fancy, but they were recognizable and set the stage for the years to come (at least for me). But I take a lot of pride in these first steps, since they show the seeds of what the future held in store, both for myself and the rest of us stock replica builders. There is a lot of growth that came between these two screenshots, but what is more interesting is what stayed the same. Larger than expected replicas, allowing for more detail Strange use of parts - airbrakes, parachutes, and communotrons are used to get colors and shapes right Using the craft to tell a story - the early series were the first planes I built in my Jet of the Day series As we move forwards into a new decade, remember to look back and reflect on how far you've come, and just think how much farther you have left to climb. Here's to a good 2020 -Servo

Big upload today - as is my tradition, around New Years, I return to the craft that I've built in the past as a reflective exercise to appreciate how far I've come. This year is a big one for me. My New Years upload last year was the F-101 Voodoo (second from the right), to compliment the F-100 Super Sabre that I uploaded earlier that year (far right). This year, I wanted to continue the series, so I planned on doing the F-105 for this year. It turned out all right, but wasn't the special upgrade that I was hoping for to wrap up a year filled with my best craft yet. To complement my slower upload schedule (turns out, Junior year in aerospace engineering is tough), I decided to challenge myself to complete the Century Series in time for New Years Eve. Depending on which time zone you're in, I succeeded. The Delta Dagger: https://kerbalx.com/servo/F-102-Delta-Dagger_2 This was the second to last one I did. It's a fine build, nothing too fancy. Proud of the intakes and the vertical stabilizer, though. Performance is a little lackluster, but about par for 1:1s with high part count. F-104 Starfighter: https://kerbalx.com/servo/F-104-Starfighter_2 I was dreading this one, since it meant that I had to put out a craft to compare against @Kronus_Aerospace's fantastic Starfighter. I targeted a different niche with my replica, going for a lower-fidelity, but high-performance replica. It may not have every detail dead-on, but oh boy does it satisfy in terms of performance. Four panthers on a streamlined, low-part count body means that this thing absolutely nails the performance of the real thing. Cruises at high subsonic without burners, and can punch through to Mach 2 with the fires lit. It's maneuverable and fun to fly as well - and did I mention that it's only a hair over 200 parts? (If you can't tell, I'm very proud of this build) The Republic F-105 Thunderchief: https://kerbalx.com/servo/F-105-Thunderchief_2 The craft that inspired this whole thing. The intakes were the hardest part, which is tough since they're the focus of the plane. I'm happy with my solution, but mainly since I think it's the best that I can do given the parts in the game currently. If only the basic fin didn't have those pegs on it... However, I am happy with how the fuselage turned out, especially the engine nozzle. It's so fun toggling the burner and watching the vanes open and close. F-106 Delta Dart: https://kerbalx.com/servo/F-106-Delta-Dart_2 The finale of the Century Series, this was the second one that I built after the F-105. How well this came together really gave me faith that I would be able to knock out the other two in the next three days. The wing on this thing is my favorite part of it (with a close second going to the cockpit), primarily because of how refreshing it is to have a 60 degree delta wing with no funny business going on. Makes me happy. Here's to another year of progress!

You need to use an image hosting site (I use imgur.com). Make an account, then use the +new post option to add images. Once you have your images uploaded, go to the images tab. Select the image you want to add next, then use the "direct link" option and copy the link there. Then paste that link into your post, and the images are automatically embedded.

Might be that the vertical stabilizers are off - the trailing edge is straight vertical on the F-15, not swept back. Looking good everywhere else, though! Just when I was on the verge of completing the F-111, the wings became much more unreliable. I think it has to do with the hinge mechanism, so I'm reworking it. Which of course, leads to reworking the docking actuation, and then to the moving bits. So I'm basically back on the drawing board. I was following a promising spur in the form of collision-hinges for pure-stock builds, but they're not consistent enough for swing wings, and the geometry just doesn't quite work, unfortunately. Someone else may find this idea useful, though. At the hinge point is a series of stacked separators or docking ports all offset into each other. They are the weakest joint in the game, so they act as a flexible attachment. From there, airbrakes force I-beams around, aided by the same-vessel-collision function added in 1.7 and rigid attachment. This works remarkably well on low-angle actuations, so I can see this having applications to stabilators. Unfortunately, the range of motion isn't quite good enough for swing wings quite yet. To take my mind off of those troubles, I've been distracting myself with a couple new projects. Hopefully, I can collect them all in time for New Year's Eve There's something satisfying in the simplicity of a 60 degree sweep delta wing. The end goal is to replicate this three-year-old screenshot, but with all-new planes. I dropped this set on NYE 2016, so hopefully I'll make the mark for 2019