MA_VMF Posted April 9 Posted April 9 2 часа назад, tavarish palkovnik сказал: Your function in area where differ the most is about i58 1,45 so just as sample what it makes in flight, 1,35 vs 1,45 I think this is a margin of error.
tavarish palkovnik Posted April 9 Posted April 9 (edited) 3 hours ago, MA_VMF said: I think this is a margin of error. Fully agree ! Beside that...final drag coefficient, from angle of attack induced one, goes in drag force Edited April 9 by tavarish palkovnik
Seb Posted April 11 Posted April 11 (edited) Разработчики, а почему у Вас в игре ракета (коррект. НАР) С-25Л при срыве захвата может самоуничтожаться в воздухе? У неё нет самоликвидатора в принципе, она наследует электромеханический взрыватель от НАР С-25, он либо мгновенного действия, либо работает с замедлением. Исправить! Цитата При нажатии на боевую кнопку происходит подача электрических импульсов на электровоспламенители источников питания и ДУК. Через 1 сек, необходимую для выхода на режим бортовых источников питания , происходит подача электрических импульсов на электровоспламенители двигателя, арретира ДУК и на зарядку конденсаторов взрывательного устройства И-415, предварительно установленного на замедленное или мгновенное действие тумблером в кабине летчик. В случаи отсутствия с ГСН сигнала о захвате цели или при отсутствии сигнала лазера летчик имеет возможность выполнить боевую задачу, осуществив пуск ракеты С-25ЛД в режиме неуправляемой ракеты с дальности, указанной в инструкции летчику. При нажатии на боевую кнопку рули в БУ переводятся во флюгирующий режим. http://xn--80aafy5bs.xn--p1ai/aviamuseum/dvigateli-i-vooruzhenie/aviatsionnoe-vooruzhenie/sssr/aviatsionnye-rakety/upravlyaemye-rakety/ur-vozduh-poverhnost/takticheskaya-aviatsionnaya-raketa-maloj-dalnosti-s-25ld/ Edited April 11 by Seb 3
okopanja Posted April 14 Posted April 14 @tavarish palkovnik 1 WARNING: my discord account was taken over. I did recover it, but process of applying preventive measures is still ongoing.
tripod3 Posted April 19 Posted April 19 ОТРК делаются ли? Точка-У, искандер, АТАКМС, Дунь Фен-15 Когда отменят потолок 100 км для ракет? 1 Mr. Croco
foxhound592 Posted April 20 Posted April 20 @Chizh Будет ли новый апи для Р-73 с выходом модуля миг29? 1
SkyStorm Posted April 22 Posted April 22 Всем привет! Ракеты Р-27ЭР стали самонаводящимися, как будто они активные, только у меня? Заметил, что ракеты Р-27ЭР стали попадать после срыва захвата (применял с СУ-27). Решил поэкспериментировать и увидел, что ракета, выпущенная на разрешенной дальности по не маневрирующей цели поражает цель (бота на F/A-18C) даже если практически сразу после пуска развернуть самолет на 180 градусов и отключить РЛС. При этом бот не летит по прямой а совершает некий маневр. Однако с ракетами Р-27Р так не происходит, и ракета начинает лететь просто по прямой сразу после срыва захвата. Разве так и должно быть? Трек прилагаю Р-27ЭР.trk
MA_VMF Posted May 11 Posted May 11 (edited) Спойлер 1.5М Спойлер 1.7М Спойлер 2М Edited May 12 by MA_VMF
tavarish palkovnik Posted May 12 Posted May 12 On 5/11/2025 at 2:41 PM, MA_VMF said: Reveal hidden contents 1.5М Reveal hidden contents 1.7М Reveal hidden contents 2М Content is not visible Hit it one more time, and with note what it presents
MA_VMF Posted May 12 Posted May 12 4 минуты назад, tavarish palkovnik сказал: Content is not visible Hit it one more time, and with note what it presents Thanks for pointing out the problem. It should show
tavarish palkovnik Posted May 19 Posted May 19 @MA_VMF Will you give some words about these results. Grid fin obviously and you showed us dynamic pressure values. But this pressure is actually the easiest part of these calculations, simply density * velocity^2 * 1/2 … 1,225*680^2*1/2=283220 Pa To me and for most others I guess, all these CFD modelings are “gold” digging where “gold” are Cx and Cy coefficients in function of Mach. When having these coefficients everything else is just piece of cake. So how you find those coefficients? I guess software gives you drag force and from that Cx coefficients just drop out. So why and what for dynamic pressure? Just from curiosity, how long it takes, with some reasonable calculation grid, to get drag forces on let’s say 10 different Mach numbers at same altitude? Hours or days? Generally, what takes the most time, making 3D model, or defining initial conditions or simply time computer needs to process data? By the way, R-33, is it finished I really don’t have clue how long it could take for one rocket to get ballistic data from software. Yesterday, boring Sunday afternoon, I processed on rocket and let’s say in two and half hours I got Cx, Cy and roughly moment situations to define static stabilities of rocket depending of altitude, velocity and angle of attack Maybe I’m just wrong and taking all that very simplified, but I question myself, why internet is not already filled with mostly all, if not all, rockets processed Of course others are also welcome to share thoughts
MA_VMF Posted May 19 Posted May 19 27 минут назад, tavarish palkovnik сказал: @MA_VMF Will you give some words about these results. Grid fin obviously and you showed us dynamic pressure values. But this pressure is actually the easiest part of these calculations, simply density * velocity^2 * 1/2 … 1,225*680^2*1/2=283220 Pa To me and for most others I guess, all these CFD modelings are “gold” digging where “gold” are Cx and Cy coefficients in function of Mach. When having these coefficients everything else is just piece of cake. So how you find those coefficients? I guess software gives you drag force and from that Cx coefficients just drop out. So why and what for dynamic pressure? Just from curiosity, how long it takes, with some reasonable calculation grid, to get drag forces on let’s say 10 different Mach numbers at same altitude? Hours or days? Generally, what takes the most time, making 3D model, or defining initial conditions or simply time computer needs to process data? By the way, R-33, is it finished I really don’t have clue how long it could take for one rocket to get ballistic data from software. Yesterday, boring Sunday afternoon, I processed on rocket and let’s say in two and half hours I got Cx, Cy and roughly moment situations to define static stabilities of rocket depending of altitude, velocity and angle of attack Maybe I’m just wrong and taking all that very simplified, but I question myself, why internet is not already filled with mostly all, if not all, rockets processed Of course others are also welcome to share thoughts The BBCRF is doing this, I'm just taking the calculations from it and posting them here.
tavarish palkovnik Posted May 30 Posted May 30 Couple of new ones, actually one lately just remodeled (513-1) and other (507) started from blank Both motors are with significant sliver stage, one maybe with a bit to long but I don’t see some other reasonable configuration except this 6-points star Although geometrically quite different, total impulse and propellant weight nearly same, under 6% difference For 513-1 I’m quite sure now it is with 8-points star, for 507 not fully sure in this 6, so if someone has some helpful graphics it would be appreciated
tavarish palkovnik Posted June 5 Posted June 5 Nice view on motor interior (radiography) I had, and still have dilemma, first I was on side of HARM motor, then split it 50:50 between HARM and Sparrow, but after reconsideration, this should be most likely image showing Mk58 motor
MA_VMF Posted June 6 Posted June 6 В 05.04.2025 в 09:04, nighthawk2174 сказал: May be relevant nonsense
Кош Posted June 16 Posted June 16 (edited) Не знаю, может уже отвечали. В DCS, система типа как кидает вероятность захвата цели или помехи, и дальше уже строит логику попадания туда или туда. Но зависима ли от этого логика взрывателя? У меня впечатление что там все взаимосвязано и если вероятностью выбрался "промах" то взрыватель дальше не работает. Например при фронтальных ракурсах - ракета захватила помеху сзади самолета, пролетела мимо на расстоянии меньше длины самолета, и взорвалась сзади. Edited June 16 by Кош ППС АВТ 100 60 36 Ф < | > ! ПД К i5-10600k/32GB 3600/SSD NVME/4070ti/2560x1440'32/VPC T-50 VPC T-50CM3 throttle Saitek combat rudder
nighthawk2174 Posted July 2 Posted July 2 On 5/19/2025 at 11:10 AM, tavarish palkovnik said: @MA_VMF Will you give some words about these results. Grid fin obviously and you showed us dynamic pressure values. But this pressure is actually the easiest part of these calculations, simply density * velocity^2 * 1/2 … 1,225*680^2*1/2=283220 Pa To me and for most others I guess, all these CFD modelings are “gold” digging where “gold” are Cx and Cy coefficients in function of Mach. When having these coefficients everything else is just piece of cake. So how you find those coefficients? I guess software gives you drag force and from that Cx coefficients just drop out. So why and what for dynamic pressure? Just from curiosity, how long it takes, with some reasonable calculation grid, to get drag forces on let’s say 10 different Mach numbers at same altitude? Hours or days? Generally, what takes the most time, making 3D model, or defining initial conditions or simply time computer needs to process data? By the way, R-33, is it finished I really don’t have clue how long it could take for one rocket to get ballistic data from software. Yesterday, boring Sunday afternoon, I processed on rocket and let’s say in two and half hours I got Cx, Cy and roughly moment situations to define static stabilities of rocket depending of altitude, velocity and angle of attack Maybe I’m just wrong and taking all that very simplified, but I question myself, why internet is not already filled with mostly all, if not all, rockets processed Of course others are also welcome to share thoughts Dynamic pressure is usefull for viewing shocks as the pressure drop post shock is rather quite easy to see. The CFD results point to why lattice fins tend to really only come into their own at very high mach numbers. the shocks are still at a relativly low angle and are interacting well inside the lattice structure. Resulting in chocked flow aka higher drag. For CFD the amount of time it takes can wildly vary. It depends on how accurate you want to be. More accurate you need a higher quiality 3D model, denser mesh, and more data points simulated. It can range from days of work to months. To build out enough data points with a reasonable model/mesh for a proper FM I'd lean towards longer rather then shorter. The software itself will pretty much give you those axial force coeficents and with some work the center of pressure can be found as well, you can often calculate these for individual components rather easily as well. With said components a flight model can be built.
nighthawk2174 Posted July 2 Posted July 2 (edited) On 6/6/2025 at 5:41 AM, MA_VMF said: nonsense This is a well-known limitation of lattice fins; it doesn't matter what you believe lattice fins are a not some big unkown. The data comes from a publicly available report. There's a reason no one is using lattice fins on their latest missiles anymore not the Europeans, Americans, Chinese, Japanese, Koreans, etc. The improvements you could possibly get, you can achieve more effectively without the downsides by using thrust vectoring. ANALYSIS OF GRID FINS AS EFFICIENT CONTROL SURFACE IN COMPARISON TO CONVENTIONAL PLANAR FINS Edited July 2 by nighthawk2174
MA_VMF Posted July 3 Posted July 3 19 часов назад, nighthawk2174 сказал: This is a well-known limitation of lattice fins; it doesn't matter what you believe lattice fins are a not some big unkown. The data comes from a publicly available report. There's a reason no one is using lattice fins on their latest missiles anymore not the Europeans, Americans, Chinese, Japanese, Koreans, etc. The improvements you could possibly get, you can achieve more effectively without the downsides by using thrust vectoring. ANALYSIS OF GRID FINS AS EFFICIENT CONTROL SURFACE IN COMPARISON TO CONVENTIONAL PLANAR FINS You need to compare two rudders of the same area. This study is complete nonsense
nighthawk2174 Posted July 3 Posted July 3 (edited) 3 hours ago, MA_VMF said: You need to compare two rudders of the same area. This study is complete nonsense No this study is perfecly valid you're just coping. The study is practical in that it compares two similarly sized fins. If you were to make the monoplane fin have the same reference area as the lattice it would be impractically large. Even then the advantages of the monoplane in L/D and static stability would still persist. Just fundamentally the lattice will have higher drag then a similarly sized monoplane fin due to shock interactions especially at lower mach numbers. This persists up to ~M3.5+ when the shock interactions occur aft of the lattice instead of inside the lattice cells. There is no getting around this whether or not your comparing two similarly sized fins or two that have the same reference area. Below the blunt shock ahead of the lattice is a clear indication of chocked flow and is why there is a dramatic increase in drag coefficent. NOTE the above is NOT my work I just coppied it from another forum where this exact same disscusion happened. You can calculate this point yourself if you want just lookup the oblique shock tables or follow this: 19930091059.pdf These studies help prove my point I wish I still had access as I did a few years ago but if your willing to pay they prove my point: Subsonic/transonic free-flight tests of a generic missile with grid fins | Aerospace Sciences Meetings Subsonic Flow CFD Investigation of Canard-Controlled Missile with Planar and Grid Fins | Aerospace Sciences Meetings Edited July 3 by nighthawk2174
MA_VMF Posted July 4 Posted July 4 14 часов назад, nighthawk2174 сказал: No this study is perfecly valid you're just coping. The study is practical in that it compares two similarly sized fins. If you were to make the monoplane fin have the same reference area as the lattice it would be impractically large. Even then the advantages of the monoplane in L/D and static stability would still persist. Just fundamentally the lattice will have higher drag then a similarly sized monoplane fin due to shock interactions especially at lower mach numbers. This persists up to ~M3.5+ when the shock interactions occur aft of the lattice instead of inside the lattice cells. There is no getting around this whether or not your comparing two similarly sized fins or two that have the same reference area. Below the blunt shock ahead of the lattice is a clear indication of chocked flow and is why there is a dramatic increase in drag coefficent. NOTE the above is NOT my work I just coppied it from another forum where this exact same disscusion happened. You can calculate this point yourself if you want just lookup the oblique shock tables or follow this: 19930091059.pdf These studies help prove my point I wish I still had access as I did a few years ago but if your willing to pay they prove my point: Subsonic/transonic free-flight tests of a generic missile with grid fins | Aerospace Sciences Meetings Subsonic Flow CFD Investigation of Canard-Controlled Missile with Planar and Grid Fins | Aerospace Sciences Meetings the advantage of the lattice is that it can be made smaller than a monoplane wing, while maintaining the same torque as a monoplane fin
okopanja Posted July 4 Posted July 4 Not sure why so much discussion on grid fines, especially in sub-sonic and transsionic range: 1. Launch platform can accelerate beyond transsonic range 2. majority of DCS missiles are between 2-3 Mach when they hit, which means the aircraft and missiles are most of the time in super sonic range. Therefore what matters is actual performance in super sonic range. 1 WARNING: my discord account was taken over. I did recover it, but process of applying preventive measures is still ongoing.
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