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Yo-Yo

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  1. Yo-Yo

    DCS: И-16

    Нужно видеть глаз белки или белочки?
  2. I can not agree, that in RL is harder to obtain steady flight because in RL a pilot has instant acceleration feedback.
  3. You are absolutely right. The best way to use variometer is to combine its readings with aircraft pitch (horisont line, clouds, etc) to have steady pitch (steady g-load=1) for a certain time. It's not a big mistake, for example, to have -0.5 m/s for 10 seconds, then +0.5 for another 10 seconds and take the average from two TAS readings. The most accurate way to obtain it is to use, of course, energy curve. If the flight was steady for a while, the real max speed can not be even reached a bit, but extrapolation wil give the exact value.
  4. We have to take in account two main ways of formation turns: predetermined or combat, when leader and wingman can switch sides, and the way they flies in DCS from the ancient times, when the side and formation type are set from the start and can be changed only after leader command. So, the first one is new for DCS and is in plans , it is a bit easier. The task we work on now is to maintain our four planes together in DCS formation to obtain compatibility with the old AI. This kind of turn is still useful for not steep turns, on the route, for example. Yes, it is a good point, and we are discussing the way leader could signal the turn. It's not a big problem, if the leader is AI, but can be a problem for human leader. Anyway, we will try to prepare some ways to sand this issue.
  5. I watched your track and I can say that the problem is not in the FM but more in the way you are trying to measure the speed. Even with ideal trim the plane was not hold at the same altitude for a reasonable time to find the max speed. Then, as I made the same E-record for you track, I noticed that there is a significant difference between my test and yours: as you can see, the points that are filtered for g=1 with small tolerance are very dispersed for TRIMMED flight and, vice versa, more condensed for UNTRIMMED. It is an evidence that your flight was performed with constant g changes, small, but bleeding enough energy, For untrimmed flight the points are more solid, more organized, and the speed is exactly as in my test. I can suggest that it could be a joystick issue, so for these precise tests the curve must be set like this. null null
  6. This is very interesting material from one of our user, or, I should say unofficial tester with great engineering experience. Just in case, to start interest I asked Chat GPT to translate the material here, diagrams for them one can see in the original place. The reasons here are obvious - the aircraft's armament has changed. In general, adjusting the machine guns on an aircraft is a rather interesting topic. But not in terms of the armament itself - that part is clear. It's a perfect example of how the internet influences the process of destroying human knowledge. In the past, in order to acquire reliable knowledge on a particular subject (or at least what was considered reliable at the time), one had to go to the library. Books (especially technical ones) were the result of human intellectual effort, and everything presented in them had been extensively tested, reviewed, and approved by specialists. The likelihood of obtaining unreliable knowledge was extremely low. Currently, books are no longer a source of knowledge. The source of knowledge nowadays is a line in any search engine, providing links to countless rambling articles written by people who have no understanding of the subject matter they write about, engaging in senseless information copying from one internet page to another, often with their own interpretation of well-known facts at a level accessible to their understanding. The paradox of the situation is that now it is easier than ever to obtain the necessary book on a particular subject. Not only can anyone sign up for scientific and technical libraries and the Russian State Library (formerly known as the Lenin Library), but also a multitude of books have been digitized and are freely accessible. However, no one reads them. I speak from personal experience - about ten years ago, I digitized and published excerpts from a book on aerial marksmanship theory on the internet. Among other things, it provided a detailed analysis of the principles of weapon alignment, and on various forums, I would say, "Look, this is how it is, and this is how it should be read and studied." What do we have now? We open the internet and observe a variety of nonsense about how the alignment distance of weapons depends on the individual characteristics of the pilot and should be adjusted independently. The mechanism of spreading this "knowledge" is evident - people take the path of least resistance. To understand a certain issue, one needs to exert certain (and sometimes quite significant) efforts. To follow "common sense logic," no effort is needed. From the perspective of "common sense logic," everything is extremely simple and understandable - bullets fly in an arc, and wing-mounted machine guns are also at a certain distance from each other, so in order to hit an aerial target, the trajectories of bullets and the aiming line must intersect; such intersection is only possible at a certain distance, so you should shoot at that distance, otherwise, you will miss. And since this distance depends on the individual style of aerial combat - it should be adjusted individually. Many go even further and talk about how important it is to accurately determine the distance to the target during aerial combat - it's all so logical that only a fool would object. At one point, they even bothered veterans with questions like, "At what distance were the machine guns aligned in your regiment?" Interestingly, "common sense logic" explains the world around us not just "a little bit wrong," but completely opposite! According to common sense logic, the sun revolves around the earth - in the real world, it's the opposite. According to common sense logic, a synchronizer interrupter of a machine gun delays the shot when the propeller blade passes the barrel - in the real world, it's the opposite. According to common sense logic, an airborne gunner with zero dispersion machine guns (they even came up with a special term: "laser guns") would hit a squirrel in the eye from a kilometer away - in the real world, it's the opposite: the probability of hitting the target would be zero. The same applies to the alignment of machine guns. Machine gun alignment is not done **************************************************** We can see that zeroing the wing machine guns at a distance of 400 meters provides continuous engagement space in the range of 85 to 520 meters from the aircraft. In other words, by aiming the sights at the center of the target and without making any adjustments for trajectory drop, the shooter will reliably hit a target located at any distance from the aircraft within the range of 85 to 520 meters. This applies, of course, to shooting head-on or in pursuit. Shooting at crossing courses requires the use of a circular sight, which is a topic for a separate discussion. It should be noted that these are the bullet flight trajectories for ground conditions. In the air, the bullet's initial velocity will increase due to the aircraft's own speed, and the air density will decrease. As a result, the bullet will fly higher and farther, and the point where its trajectory intersects the aiming line will shift forward by about a hundred meters. Therefore, zeroing at "400 meters" will become zeroing at "500 meters". It is interesting to consider whether proponents of "adjusting the sighting to individual combat style" take this into account. Furthermore, in the illustration shown above, we can observe another interesting feature: the vertical zeroing of the wing machine guns on the I-16 (the distance from the gun to the sight is 1 meter, slightly more for the I-16: 1070 cm, but this difference can be neglected) at 400 meters is identical to zeroing at 200 meters; it's just that at 200 meters, the bullet's trajectory intersects with the aiming line in its ascending part, while at 400 meters, it intersects in the descending part. What will happen if the machine guns are zeroed at 600 meters? Nothing good: in the engagement space at medium distances, there will be a "gap" where bullets will fly above the upper dimension of the target, resulting in a guaranteed miss. ******************* eroing at 100 meters? Not any better. And that's on the ground! In the air, the bullet trajectory will be higher, and the upper machine guns at medium distances will also shoot past the target. Additionally, in the illustration, the upper machine guns are positioned 0.5 meters below the sight, and in the case of the modeled I-16 Type 24 in this simulator, they are positioned 0.2 meters below the sight, which means the trajectory is even higher. ******************* From all of this, we can conclude that the zeroing of the machine guns on the ground should be such that the bullet trajectory at its highest point is slightly below the upper limit of the target (0.5 meters above the sight line). Therefore, for the I-16 with its "two-tier" armament arrangement, the optimal option is 200 meters (in the illustration, the upper machine guns are positioned 0.5 meters below the sight, and in the case of the I-16 Type 24, they are positioned 0.2 meters below the sight: the trajectory will be slightly higher, but there is a margin). We can relax the criterion for target engagement in the horizontal plane and consider the critical zone to be 1.5 meters wide instead of 1 meter (as aircraft are generally wider horizontally than vertically). In that case, for the I-16 Type 5, the horizontal engagement area would start at 200 meters and end at 600 meters. The overall engagement area is the intersection of the vertical and horizontal engagement areas. Additionally, I would like to remind you that all the diagrams mentioned above are for ground shooting. In the air, the trajectories will be higher and farther, and the exact calculations would depend on the changes in air density and aircraft speed for each specific case. Therefore, we can conclude that the zeroing of the I-16 Type 5 aircraft (as described in 1937) ensured target engagement at relatively long distances: 200-600 meters. Shooting at "rivets" would be pointless. The two wing-mounted machine guns, spaced a significant distance apart, provided sufficient depth of engagement only at longer distances. Zeroing the wing-mounted machine guns at 300 meters would reduce the vertical engagement area. Zeroing the wing-mounted machine guns at 200 meters for the vertical plane is equivalent to zeroing at 400 meters, but in the horizontal plane, it would significantly reduce the engagement area to a range of 100-300 meters. Therefore, the choice of a 400-meter zeroing distance is evident for the I-16 Type 5. The need to enhance the armament by adding synchronized machine guns was also evident, and it was implemented later. What changed after adding two synchronized machine guns to the I-16? In the vertical plane: Zeroing the high-mounted synchronized machine guns (with a slight offset of 0.2 meters between the gun and the sight) at 400 meters is not desirable. Even on the ground and at medium distances, the bullet will pass close to the upper profile of the target. In the air, the bullet's speed will increase by the aircraft's own speed. The influence of the aircraft's speed of 150 m/s (540 km/h) is as follows: I have come across statements on the internet like "The sight is calibrated for a specific distance," and from there, people often draw the conclusion, using common logic, that in order to hit the target accurately, one must approach the enemy at that particular distance. In this regard, I would like to clarify the following: Ring sights are not designed for shooting at a specific distance! They are intended for shooting at any distance in effective aerial combat. The notion that "the sight is calibrated for a specific distance" obviously arises in people's minds after reading a phrase from the sight description, such as "the large ring of the sight is calibrated for a target speed of 300 km/h and a distance of 400 m at a 4/4 aspect angle." Indeed, the ring is calibrated for a distance of 400 m, but the sight itself is not! When aiming at the ring calibrated for 400 meters, the sight allows for guaranteed hits on targets at any distance from 0 to 600 meters! This can be explained as follows: If we take the extreme case and assume that the target is flying perpendicular to the shooter's course and accurately calculate the lead necessary to hit the target at various distances, we obtain a curve (dashed line in the diagram). The ballistics of Soviet ammunition were such that this curved line can be approximated by a straight line passing through the point calculated for a distance of 400 meters (hence the significance of these "sacred" 400 meters!). As a result, the bullet deviation at any distance from 0 to 600 meters does not exceed the dimensions of the same critical area of a hypothetical target measuring 1m x 1m, and the target will be hit. Indeed, the most important (and practically the only) thing a pilot needs to know about a ring sight is not "400 meters" but the speed for which the ring is calibrated! This greatly simplifies the shooter's task. It is sufficient to estimate the speed and aspect angle of the target and mentally adjust the size of the ring proportionally to the speed and aspect angle. As long as the distance to the target does not exceed 600 meters, it will be hit (assuming the estimation is done correctly, which can be challenging). The pilot doesn't need to worry about the exact distance to the target (as long as it is within 600 meters). That's the essence of aiming with ring sights. There was a topic and research conducted on this matter. In brief, the essence of these findings is as follows: Zero dispersion for aerial shooting means zero probability of hitting the target. This statement may seem strange to many, but it is important to understand that aerial shooting is fundamentally different from shooting, for example, with a sniper rifle. For a sniper, who takes a single shot, low dispersion is desirable, ideally aiming for zero dispersion. However, in aerial shooting, both the target and the shooter are in continuous motion. Therefore, aerial shooting is more akin to shooting at ducks with a shotgun, where the pellets are not fired simultaneously but sequentially. If we imagine hypothetically that an aerial shooter is using a weapon with zero dispersion and the target is not extremely close, where missing is impossible, the shooter will never hit the target with the first burst. This is because there will always be some error in aiming, and the burst will pass by without the shooter knowing which way to correct since without tracers, it is not visible, and even with tracers, it is not straightforward because they show the ascending branch of the bullet's trajectory, which does not coincide with the direction of the potential hit point. If the targeted aircraft, assuming it's not foolish, notices that it is being fired upon, it will start maneuvering, making it even more challenging to hit. Likewise, the probability of hitting the target with a weapon with significant dispersion is also zero. It is evident that if the bullets fly in all directions, hitting the target becomes impossible. From these observations, a logical conclusion was drawn: there exists an optimal dispersion level between zero and infinity, where the probability of hitting the target is maximized. Practical shooting tests were conducted, and the results helped determine the approximate boundaries of this optimal dispersion, which turned out to be several times greater than the inherent dispersion of the aviation machine guns and cannons available at the time. Another logical inference was made: it would be beneficial to vary the dispersion during shooting! Corresponding mechanized mounts were developed, tested, and their results obtained. However, at that moment, the weapon designers quickly reconsidered their approach. This was because it did not make much sense to install devices in an aircraft that artificially increased dispersion when the pilot could easily control dispersion by himself! Indeed, with a burst, the pilot can simply adjust the dispersion by slightly pressing the pedal, and there you have it – dispersion is achieved! Additionally, any defensive burst can be seen as a burst with dispersion. Instead of considering it as a flock of bullets flying one after another towards an approaching aircraft, it can be viewed as a stationary aircraft in the sky with a series of trajectories converging towards it at some interval – that's dispersion! Moreover, increasing the number of wing-mounted machine guns for the British and American pilots allowed for a decent dispersion without any mechanisms. Many have likely seen images like the one provided. Here, the area of engagement is expanded by adjusting the sighting distances for different groups of machine guns. It's not a panacea, but still quite effective. Knowing the width and height of the total dispersion, it is easy to obtain its probable deviation in the lateral and vertical directions (in the case of circular distribution, they will be the same) – it is 1/8 of the total dispersion value. In this case, the probable deviation will be 1 mil. This is a very small value. For example, in the Soviet Union, the probable linear deviation of technical dispersion (in meters) was considered to be 1.5t, where t is the bullet flight time. For ShKAS (referring to the I-16 Type 24 sighting table), the bullet flight time at a distance of 300 meters and an altitude of 4,000 is 0.35 seconds. Consequently, the linear value of technical dispersion for ballistic calculations at this distance is 1.5 * 0.35 = 0.525 meters. In angular terms, this is 0.525 / 300 * 1,000 = 1.2 mils. From this, it can be concluded that the influence of wing vibration on the dispersion of weapons installed in the wing, at least for the Americans, was not particularly significant – it was not even considered in the calculations. The "multi-level" sighting played a much larger role. In this regard, it is interesting to see how the Germans approached this issue. Looking at the Focke-Wulf sighting card, it immediately catches the eye that they consider the critical zone target size not as 1 meter or 1.5 meters, but as 1.2 meters! That's what German precision means! Another interesting point is that in their sighting calculations, they use data on the technical dispersion of the weapon, and they determine the depth of the hit zone not based on the intersection of the "ideal" bullet trajectory with the target size, but based on the intersection of the inner edge of the dispersion ellipse with the target size (vertical dotted lines on the diagram) – the calculated hit zone is thus enlarged. And they conduct sighting not at 400 meters or 200 meters, but at 300 meters – well, they decided that it would work better with their ballistics. So, what about the probable deviation of technical dispersion for them? It is specific to each weapon model (figures on the right side of the diagram in percentages). "Waffenstreuung" is the width of the band in the dispersion ellipse that contains 50% of the best hits. The probable deviation is half the width of this band. For MG 17 and MG 151: 0.25%. Therefore, the lateral probable deviation is 1,000 * 0.25 / 100 / 2 = 1.25 mils. Practically the same as in the USSR. It is also worth noting the significantly smaller technical dispersion of the wing-mounted MG FF: 0.125% – not even a hint of considering any consequences of vibration!
  7. Ok, I tested it carefully. As you can see both rudder trim position give the same energy and, thus, max speed. Screenshots show needle position for both cases. Vvert equiv on the chart is Vvet equiv 2
  8. I am sure that you overestimate the drag relative for 42 m2 wing area.
  9. I can only say that in DCS it flies exactly at 340 mph, if you set 20000 lb (has very low effect on top speed though), 760mm/15C, and manually close radiators. To make sure that 544 kph TAS is real max speed and a point of equilibrium I always use excessive power record filtered for 1g to avoid load/unload effect on the drag. And this is the record, so one can see that zero point is exactly 340 mph. I can not agree that exhaust shrouds can give drag comparable with 8 pylons with rockets (~20 mph). null null
  10. The statement "oh, 15 mph slower, we lost the war!" is very far from the real things. First of all, though we have, I think, the most full collection of Mosquito reports, we really have no report with clearly figured TAS for the same plane we have in DCS, except poor FB VI HJ 679 that was presumed crippled (but without finding actual reasons of this behavior). Then we have DCS FB VI top speed at SL 340 mph Then, we have FB VI sax-HX809 with 18lb/3000 measurements, that state 354-22 = 332 mph at SL. By the way, for all other tests that have no direct SL measurements, SL speed is obtained by prolonged graphs. Then we have B IV DK. 290 tested for both types of exhaust system, that shows 15 mph difference. So, if someone wants to use this information to suggest the top speed of FB VI with normal exhaust, this speed is to be 332+15 = 348 mph (and the difference with DCS will be only 8 mph), but below I will show, why DK. 290 can not be used as a reference even for the different types of exhaust systems. Please keep in mind that all planes used for comparison have engines with the same blower ratio, so 21/23/25 have only different limitations, so, the power can be compared directly. looking at DK.290 results one can see that they are incredible high for 9 lb/3000 - 331 mph, tanks on, M.S. that gives 337 mph (6 mph difference obtained from 8000 ft measurements common for tank on and off) And we have sax-FB VI HS.918... That shows glorious 302 mph without tanks and RP at (drum roll!) 12.5lb/3000, and it directly shows without any calculations that FB VI itself is much more draggy than B IV, thus 15 mph sax/no-sax difference is not fully valid for FB VI. And then I performed some calculations to obtain more accurate numbers taking in account prop thrust and jet thrust. Radiator drag/thrust at these speeds are close to zero and thus can be neglected in comparison even to jet thrust. I omitted the calculations itself, and these are results. DK. 290 with normal exhaust shows CD0 very close to the values stated in other reports, and, that is interesting, to get -15 mph with sax, jet thrust must be reduced to~0 (I do not think, that additional streamlined construction can make such high drag). It is plausible if the gases temperature/energy was significantly reduced before they ejected backwards. Now we can eliminate jet thrust for sax-FB VI HX809 and find its drag using test results. And its drag is 1/3 more than for B IV. Using this obtained drag we can add jet thrust for 18 lb/3000 and find that non-sax FB VI must fly at 344 mph, that lays within 1% tolerance. We can also check FB IV using HS.918 results: drag obtained from the same calculations is 5% higher than for HS.918, so we have reliable result. And, by the way, it shows that these two planes will have at least 2.5% difference in top speed.
  11. Yo-Yo

    DCS: И-16

    Разработчиков - расстрелять за изменение. Кстати, отзывы современных летчиков об устойчивости и управляемости И-16 можете не брать за религиозную догму, современные реплики имеют центровку более переднюю, чем оигинальная.
  12. Сегодня Эриху исполнилось бы 100 лет.
  13. Это известные в советских источниках т.н. "лопатки Поликовского". Все бы хорошо, но первые Jumo-213A уже с подобным устройством были выпущены еще в 1940 году, если верить источикам. А немецкий отчет датирован августом 1942 и, судя по тексту, отчет был сделан по результатам исследования трофейных советских двигателей, что означает, что исследования начались не ранее июня 1941 года. Можно конечно предположить, что немецкая разведка принесла эти лопатки в клювике немецким конструкторам еще до 1940 года, но это пока доступными документами не подтверждается. Кстати... подобный способ с лопатками на входе не является оптимальным с точки зрения эффективности решения задачи выравнивания мощности по высоте при ограниченном давлении наддува. Самый неэффективный - это тупое дросселирование: на малой высоте нагнетатель пережал воздух, при этом очень сильно его нагрев. Давление-то мы задросселируем, а вот температура после этого останется. Отсюда и меньшая плотность массового заряда, меньшая индикаторная мощность. Да еще вдобавок на перегрев воздуха пошла лишняя энергия. А откуда она взялась? Правильно, отобралась от вала. Можно сделать две или даже три скорости вращения импеллера нагнетателя, чтобы на малой высоте он меньше впустую молотил воздух. Так, в основном, все и делали. Но проблема, хоть и поменьше, остается. Все равно ниже критических высот для каждой скорости мощность падает, хотя и намного меньше, чем при односкоростном. Самый лучший способ, точнее два - это плавная регулировака скорости нагнетателя (DB-60X), когда приводной нагнетатель крутится ровно с такой скоростью, чтобы обеспечивать максимальный наддув (ну чуть-чуть с запасом, конечно), тогда мощность двигателя даже растет с уменьшением высоты. И, конечно, турбонаддув, который за счет энергии выхлопа позволяет сохранять мощность двигателя постоянной в очень большом диапазоне высот. Поворотные лопатки, если они использованы в односкоростном высотном нагнетателе, находятся по эффективности где-то между дросселированием и многоскоростным нагнетателем. В случае же двухскоростного они позволяют несколько улучшить мощностные характеристики мотора, сгладив провалы высотной характеристики.
  14. It's not criminal to use throttle for fine adjustment.
  15. I think, there is a simple rule of thumb: add turbocharger as a last mean when rpm are set, throttle at max and you have lack of MP. And as you reduce power (MP), turbo must be retarded first. It is very unwise to let turbo overcompress the air and then throttle it down.
  16. This is the video, with two landings. Bf-109 landing was with dead engine, Spitfire - with power-on approach, and the power was set to idle just at touchdown, that was two-wheels (unexpected), that means that the speed was a bit higher. And both cases show that the plane must be flied to full stop :)/
  17. If you have right IAS as you chop the throttle and are not too high over the runway, it's safe. Or if you perform final at idle but have enough speed to flare and do it right, at the right altitude over ground, it's safe. The plane will sink or even stall wing down if the flaring is too long, and the extra speed reserved for flaring is gone.
  18. Каждая задача имеет очевидное, простое, но неправильное решение. Здесь нужно изменять не затяжку, а ЖЕСТКОСТЬ пружины. А это совсем не то же самое. А если делать быстрый и мощный мотор, который тянет или отпускает пружину, создавая требуемые мгновенные усилия, то проще уже просто с PowerFFB. А если уж медленный - то это нужно менят передаточное отношение к пружине. Причем в очень больших пределах.
  19. С большим опозданием дошел до меня номер виртуального журнала "Вирпил", в котором в очередной раз поднимается вопрос управления в симуляторах. Wad попросил что-то сказать по поводу этой статьи. Получилась целая рецензия. Очень надеюсь, что в итоге вопросы по управлению будут окончательно закрыты, и предложения о "резиновой ручке больше поступать не будут. virtpilot30.pdf Будем считать это краткой и неполной рецензией на статью.doc
  20. С большим опозданием дошел до меня номер виртуального журнала "Вирпил", в котором в очередной раз поднимается вопрос управления в симуляторах. Wad попросил что-то сказать по поводу этой статьи. Получилась целая рецензия. Очень надеюсь, что в итоге вопросы по управлению будут окончательно закрыты, и предложения о "резиновой ручке больше поступать не будут. Будем считать это краткой и неполной рецензией на статью.doc
  21. Yo-Yo

    Turbulence

    Yes, the turbulence, as you feel it, becomes lower as you climb. It is well known phenomena, because the correlation length of the turbulence becomes longer with altitude. Tests conducted shows that strong (for pilot's opinion) turbulence at 300-500 m feels like very light at ~2000 m and higher. It is not relevant for in-cloud thunderstorm turbulence because it has very different nature and velocity distribution.
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