Kronus_Aerospace

I have more plans for this jet. And they are coming along rather nicely.

Maybe not, but what it does have.... Is the same functionality...

I decided to pull apart the craft and.... GOOD GOD

@eorin Thank you so much! I used Kronal Vessel Viewer, Its pretty handy.

This craft is a full stock 1:1 replica of the F-104C Starfighter. Intended to be simple replica to serve as my introduction into the world of fighter craft replica's. Instead it became one of my highest part count fighter craft and by far my most accurate replica in general. With 660 parts it's a hefty 40 tonnes, however due to how it was designed it still has decent enough aerodynamics that a bit of engine clipping has allowed it to achieve the required performance. It is able to reach mach 2.6, which is much faster than the F-104 actually ever flew at, although the F-104 possessed the power and aerodynamics to achieve such speeds, however parts like the cockpit limited its speed as it was never designed to take such strain. It has a rotation speed of 60 m/s A stall speed of 40 m/s Its maneuverability...Well, it won't exactly be flying under any bridges All pretty much what you would expect from an F-104, so not a big loss. On the development side, this craft came to together slowly but smoothly. I spent just as much time in the blueprints as did actually building it, the result was that I really had to redo or adjust many sections. This style of building is one I have been employing for a while, but this craft shows the fruits of that labor more than any other. BIG THANKS TO PHANTOM AEROSPACE! Fellow builders have been suggesting that I build a fighter replica for quite some time now, although I always refused. That is until @Phantomic suggested that I start off simple to ease my way into it, specifically the F-104. I just want to give him a huge thanks for encouraging me to build this, as it was one of the most fun replicas I have done in a long time. Please check out his craft, he makes a variety of craft from really detailed trucks and other vehicle replicas, to really sexy and practical stockprop fighter craft. https://kerbalx.com/PhantomAerospace Also you should download his own F-104C replica, it's excellently done and quite practical, plus all of that for exactly 1/10 the part count of mine, you can't beat it! https://kerbalx.com/PhantomAerospace/F-104C Download Link: https://kerbalx.com/Kronus_Aerospace/Kronus-F-104C-Starfighter

My 5.2 kiloton flying Aircraft carrier is approaching its first flight tests, There are many problems I have to figure out before then, the biggest one of which is control. Being a VTOL, control surfaces alone would be insufficient, but weighing 5200 tonnes means that a huge number of reaction wheels would be required. So I've been investigating how I could maneuver this beast. Initially I thought I would have to resort to craft file editing, and make myself some super reaction wheels, as otherwise 1000 would likely be required. However, the other day I got the idea to use Kraken Drives as orientation control. These Kraken drives could be activated using control surfaces, and allow them to control the craft using WASD. This turned out to be an amazing idea, and I'll let the results speak for themselves. This result was so much better than I could have hoped for, the testing mechanism has a simple bearing and 1.2 kilotons of weight. Doing some quick and dirty math I found that it produced 8500 kN of thrust per Kraken drive, and considering that each one is only 13 parts and 4.3 tonnes, I'd say that's pretty good. I repeated the test using Mammoth engines and reaction wheels, the Mammoth test showed significantly slower acceleration, and the Reaction Wheel test (which used the same # of parts as the Kraken Drive) was slow as mollases. In terms of power and part count, this will work perfectly for Maneuvering the Azathoth. Presuming that I use 4 for Pitch + roll, and 2 for yaw, that would only come out to 78 parts and 25.8 tonnes, including struts I'm gonna round that up to 100 parts and 26 tonnes in total, just incredible.

My 1:1 F-104 build is progressing swimmingly. Part count has shot up to a whopping 530, but the results speak for themselves. Fuselage is now completely finished. This leaves only the wings and tail fins left to be built. I suspect that these will go relatively quickly compared to the fuselage. A great deal of effort was put into the Intakes, which encompass over 100 parts alone. To make things worse, Communotrons do not mirror symmetrically, meaning that these intakes had to built without mirror mode. This fact combined with their complexity means that they take up a solid 1/3 of this craft's build time thus far. I am very proud of how this craft is coming along. By the end of this weekend I hope for it to be done. (video maybe?)

That is pretty impressive! It goes to show the incredible potential of turboprops in this game. Their efficiency and power is really unrivaled when done right.

I've built some of the most powerful turboprops out there. But that was not the topic of this discussion. That's a whole nother can of worms.

@Pds314 I have tested solar panels before for that usage, for fighter craft they are rather un-ideal as the TWR and power requirements of stock prop fighter craft mean a huge amount of solar panels would be needed, panels generate very little power for their size and on a prop would operate at very low efficiency as only half of them would be facing the sun at any one time and even then only some of them would be facing the sun directly. Mounted on the bearing shaft for the engine the panels would have only 31% the area that they would mounted flat, this is the best you can get by the way there is no magical way of mounting them to exceed that number. However, a plane will not always be flying perfectly horizontal, and over the course of a 1 hour flight the sun will not always be directly overhead, so taking those factors into account I will be instead using an efficiency of 25%. Using the smallest panels, which would be the only ones that you could easily incorporate onto the prop itself which they would need to be attached to, you'd get .0875 units of electric charge per second per panel, which works out to 8.75 units of electric charge per tonne of panels. The hypothetical prop engine outlined in this topic had power requirements of 13.65 units per second, meaning that 1.56 tonnes of panels would be required, which is 156 individual panels. This would put it on par with RTGs in terms of weight, but far behind them all in terms of part count. It is still much heavier than fuel cells. Being even more generous let's use the XL panels, even though they are so large as to be rather difficult to incorporate into most fighter craft. Using the 25% efficiency number, they generate .7 units of electric charge per second per panel, which is 17.5 units per tonne. Putting them to use in our hypothetical engine .8 tonnes of panels would be required, coming out to 20 panels total. This puts them ahead of fuel cells in terms of weight but still behind in part count. However, if we are giving the solar panels the luxury of being able to use their larger, more efficient variants, for the sake of a fair comparison we must do the same to fuel cells. The larger fuel cell arrays are around the same size as a single XL panel, however while a single XL panel generates .7 units of electric charge per second in this application, a single fuel cell array generates a whopping 18 charge per second. This comes out to a colossal 75 units of charge per second per tonne of fuel cells. A single large fuel cell would easily meet the requirements of out test engine, this would make the total weight come down to .86 tonnes to power the engine for 1 hour. It not only matches the panels' weight, but could power the engine using just 5 parts, versus the panel's 20. Keep in mind this is the most ideal scenario, the panels power generation would vary wildly as the craft maneuvered, so realistically the engine would need batteries and extra panels for auxiliary power in such a scenario, the efficiency of the panels would also only decrease if flown earlier or later in the day, and would drop to zero effectively at dawn or twilight as the sun would be shining parallel to the axis of rotation in which the panels are mounted. Panels may have some advantages for smaller engines, however since I've spent enough time on this already I won't bother doing the math for that and will simply concede the point. However the strict limitations they pack compared to all of the other power generation methods discussed, as well as being more difficult to incorporate make them simply obsolete. Of course looking at the numbers I found, even in poorer conditions for the panels they would still work, I have in the past made fully functional aircraft using them. Doesn't change the fact that they aren't the best performance wise, but outside of applications where that is important, they are perfectly applicable. Though part count wise there is no reason to use them over RTGs.

I started work on my first full scale fightercraft replica, I figured that the F-104 would be a simple start to this "genre" of replicas, however I soon discovered that the F-104 is significantly more complex than I initially anticipated. I first found a few blueprints, edited them together, and adjusted the scale to make them as useful to me as possible. These blueprints displayed various subtleties in that F-104's design that made it much more difficult to replicate using stockparts than I had thought, and the build had a somewhat rocky start. With that said, my progress has been accelerating, and the build is already solidly 1/3 complete. With a part count of 249 already (mainly due to the cockpit) It is set to be the highest part count replica of the F-104 that I know of. The intakes and rear section seem rather intimidating to tackle, but hopefully I can maintain my current momentum. The front section didn't turn out quite perfect, but overall was better than I expected.

Thanks man! You don't even want to know, but my PC is dirt cheap and has a crappy CPU. So unless you're on a laptop I suspect most people will get better performance with this craft than I did.

I've been eyeing up that plane for a long time. I even started working on it not too long ago, but lost the craft file when the game crashed whilst loading it. May try again with that one in the future. Thanks for the suggestion!

Contract No.10Generation 2 Kronus AerospaceSD-3 LancerThis fighter craft was designed to maximum function and simplicity, with only 98 parts in it's entire construction. Being only 13.5 meters long, having a wingspan of less than 10 meters, and with a service ceiling of 20km, and a maximum speed of mach 2.4, this craft is designed to penetrate unnoticed into enemy territory. It comes equipped with small drop tanks and has the capacity to carry a wide array of weapons. This craft's main feature is that it can quickly strike anywhere on the planet. At it's cruising altitude of 17 km flying at mach 2.3, it has a maximum flight-return range of 3000km (total 6000km). Since Kerbin has a circumference of just 3800 km, this craft can fly to the other side of the globe, perform it's mission, and have more than enough fuel to return home, all in just an hour. While lacking in low speed maneuverability, this craft's simplistic design and sheer practicality make it a mainstay for any air force. https://kerbalx.com/Kronus_Aerospace/Kronus-SD-3-Lancer

Thank you! The aerofoil becomes increasingly distorted as it goes down the length, the tips are a bit silly looking because of this. But the rest has a rounded over top and a flat bottom, I have since experimented with more symmetrical aerofoils and have improved on various techniques used.

Building an MD-11, yeah... that thing. Full stock as always.

How to make an Ultra Detailed replica more detailed? Add lettering!

Upon further in-game testing I have found that Large Fuel cells are especially useful, as they produce 12 times the power for less than 5 times the weight compared to fuel cells. They also operate at a higher efficiency.

Thanks! @klond Keeping with the off topic discussion, I decided to do the math on whether or not 2 axis rotation is more weight efficient if one is using 1.25 meter reaction wheels and fuel cell power. I won't bother describing the math since I imagine that you are perfectly capable of recreating it yourself (and I'm too tired right now to bother). Through testing I found that 2 axis rotation consumes 180% of the reaction wheels normal power consumption, instead of the 200% theoretically proposed. Presuming your 141% torque value, and an ideal scenario, 2 axis rotation produces about 20% more torque per tonne (that per tonne value is the weight of the entire prop assembly). For this math i kept the power generation constant, so I compared a 10 wheel 2 axis prop, to a 18 wheel single axis prop. The results would likely be different if one were to keep # of wheels constant instead of power consumption. It's not all that significant, unless you're striving for that little bit of extra performance, 2 axis rotation with 1.25 meter props is not all that fantastic. This value would be higher with 2.5 meter props as they are around 39% more power efficient (the reverse is true of .625 meter props). Considering the previously mentioned diminishing returns of the 3 axis rotation I'd speculate that it would have maybe 30-33% more torque per tonne.

@klond Your math makes sense, looking at the numbers you reached it seems far more practical to go for a 2 axis design, as 3 axis gives diminishing returns in terms of torque per power consumption, +41% to +30%. For the sake of part count I would personally go with a 2 axis prop if at all. While it may be a bit off topic, this thread is meant to discuss the more complex and in-depth side of stock props, so I don't really mind all to much.

Contract No. 04Generation 3Kronus_AerospaceTS-1C AislingThis lighter fighter craft was designed to maximize maneuverability and responsiveness. practically invulnerable to stalling and able to liquefy Kerbal intestines with 30+g maneuvers, this fighter craft is unbeatable in low speed dogfights. Any fighter larger than itself stands little chance up against this plucky aircraft. https://kerbalx.com/Kronus_Aerospace/Kronus-TS-1C-Aisling

Bradley's technique was not really central to the idea of this thread, but I will say that it is better with larger wheels. Since larger wheels are much more power efficient, the increased power generation requirements will be easily overshadowed by the increased thrust. It is likely not worth it for the smaller more inefficient wheels. That area may be helped by using LFO and fuel cells as I described, as they offer a better weight efficiency. While I'm too tired to even attempt the math now, I believe it is possible to produce a higher TWR .625 meter prop using Bradley's method if combined with fuel cell power, although part count would likely be higher as well. Regardless of the props size, or whether or not Bradley's trick is used, using fuel cells instead of RTGs will result in a higher TWR.

No, the prop is not spinning faster than the max allowed rotation speed. It is simply able to achieve a higher thrust to weight since Bradley Whistance is making use of an exploit that allows reaction wheels to increase their power output by 71 percent, in exchange for increasing power consumption by 173 percent. The low weight, high thrust, and aerodynamic efficiency of the engine is what allows it to reach those high speeds. Try the exploit yourself in a stock game, it works. Also, even though the max rotation speed hurts stock props high speed performance, the rotational speed isn't actually what matters, what matters is the actual velocity of the prop blade, so the low rotation speed cap is compensated for by making the blade diameter very large, hence why his blades are so far out from the engine itself, this also further improves TWR.

@KerikBalm that is why I prefaced the discussion by saying that this would be used for planes where unlimited range is unnecessary. Like fighter craft, where increased performance due to lower weight and part count is preferable. I can guarantee you that most people fly a stock prop fighter for half an hour at most.

Before Reading I'd recommend that you'd watch Bradley Whistance's video on his stock prop speed test. The method he outlines is not relevant to the actual math work, and simply affects the values I will be plugging in. https://www.youtube.com/watch?v=J7oc1FLnWlY&t=438s I will only discuss the resulting data in this thread to keep things simple, if you have specific questions about the math, let me know. With that out of the way, let me preface this discussion. The dominant method of powering stock props is by using RTGs, which makes sense. They continuously generate power, allowing stock props to run forever, this is great for Duna, Eve, and Laythe exploration. However, I commonly see this used on props built for fighter craft, transport aircraft, and others. While there are some cases where endless flight is desirable on Kerbin, such applications certainly do not qualify. Most people don't fly a single stock prop fighter for hours on end (without crashing). This leads to the question, are RTGs the most efficient way of powering these props? Short answer, no, but I'll explain in more detail. I am taking efficiency to mean weight in this conversation, although other uses of the term, such as part count, may also be referenced. First we must establish all of the possible methods of powering a stock prop: RTGs (duh), batteries, and fuel cells. RTGs we already discussed. Batteries would simply run the engine using their stored electric charge, and the flight would end once they run out. Fuel cells would burn LFO (Liquid Fuel + Oxidizer), continuously generating the engines power needs whilst draining LFO from on board tanks. Of course, I wouldn't even consider the fuel cells to be an option unless I had a good reason. Doing some simple math, we can find that all batteries hold 20,000 units of electric charge per tonne. How much electric charge, then, is LFO equivalent to per tonne? It depends on which of the fuel cells you are using, but for the small fuel cells this comes out to 79,934 units of electric charge per tonne of LFO, and for the large fuel cells it is 81000 units per tonne. Looking at the raw data, fuel cells are the obvious winner. However, the additional weight associated with fuel cells throws a wrench into the works, and in either case this tells us nothing about how RTGs stack up. So I will analyze these three choices in an applied setting, where I will test their mettle in a hypothetical prop that utilizes 10 of the 1.25 meter reaction wheels with 2 dumpling fuel tanks used as bearings. I did these calculations presuming that this engine would also utilize the trick described and demonstrated by Bradley Whistance's video. Using this method the reaction wheels consume roughly 2.73 times their normal power (according to my own testing), I'm using ball park numbers so any small discrepancy is irrelevant. RTGS: The 10 reaction wheels consume 13.65 units of electric charge per second, as such the engine would normally require 19 RTGs to run continuously, which themselves would weigh 1.52 tonnes. BATTERIES: To run this engine for 1 hour you would need 49,140 units of electric charge. This would require 2.457 tonnes of batteries, so those certainly aren't the best solution, although using the largest battery bank available, this would only require 13 batteries. Since the weight of the batteries required scales directly with time of flight, they are likely the most efficient in very short flights. FUEL CELLS: The smaller fuel cells generate 79,934 units of electric charge per tonne of LFO, meaning only .615 tonnes of LFO is required to run the engine for 1 hour. This amount of LFO is almost perfectly held by the 2 dumplings in the bearing, plus two oscar tanks which altogether hold .62 tonnes of LFO. In total the tanks would weigh .698 tonnes (including dead weight), and this engine would require 10 of the small fuel cells to run continuously. This adds another .5 tonnes to the total weight, bringing it up to 1.198 tonnes. As well as 14 parts, but really that's 12 since the dumplings have to be there regardless. In every possible way, the fuel cells are more efficient, while the use of dumpling bearings may seem to bias the fuel cells, in reality this does not affect the weight, and only affects part count. Using a different bearing type would only add 1 additional part, making it on par with batteries and superior to RTGs. None the less, it is far superior to both in terms of weight. This leads me to conclude that Fuel cells are the superior method for powering stockprops intended for short to medium flight times. It should also be added that it is of course possible to mix these methods together. In this one instance, it is actually beneficial. While 10 fuel cells are required to meet the continuous power generation needs, this is only by a small amount, the raw value is 9.1 fuel cells. This adds the equivalent of 540 additional electric charge generation required over the hour of flight. Since fuel cells come with 50 units of electric charge storage each, this means that 9 of them would have 450 units total, leaving us 90 units short. These 90 units can be accounted for with a single of the smallest battery pack (which has 100 units). Weighing in at a mere .005 tonnes, this change leaves us with the original part count of 12 and a reduced mass of 1.153 tonnes. So yes, it is possible that adding batteries will lead to a net increase in efficiency, however, the instance described above is the only type of scenario where this is actually the case. So limited is this possibility that even if the real value turned out to be just 9.3 instead of 9.1, then using batteries would result in a net increase in weight. Again, these results may be different for engines of differing sizes. however I can only see fuel cells being knocked from their throne with very different total flight times. For instance, short flight times where batteries' ability to instantly deliver power gives them a major advantage, and long flight times where RTGs' endless power generation eventually overcomes their initial mass costs. This may be obvious already, but just to clarify, the fact that the math above uses reaction wheels affected by Bradley Whistance's technique IN NO WAY affects the actual math or conclusions. The math above is roughly equivalent to if you had simply used 27 reaction wheels functioning under normal conditions. The objective of this thread was to demonstrate that fuel cell powered props are a lighter and more part efficient approach to powering certain stockprops. While it took a decent amount of complex work to arrive at this conclusion, in actual application fuel cell powered props are no more difficult to build or use then RTG props. There's also the small fact that a fuel cell powered prop will not only start out lighter than a RTG powered prop, but it will also get even lighter as LFO is drained throughout the flight, further increasing performance. I appreciate any questions or feedback you may have. If I made any mistakes, please let me know, and I would love to hear your thoughts on the topic. @klond I think this may interest you.