Leaderboard

I posted this elsewhere, but it kinda fits here, too, so... Sorry in advance for what must seem like a dissertation, but this is what I've learned about coaxial rotor flight dynamics. It may help to have a picture or model of the Ka50 in front of you while you read this. In a hover, the two rotor disks of the Ka-50 contra-rotating coaxial rotor helicopter are designed so that they produce the same amount of torque (due to drag) in opposite directions. The lower rotor actually produces less lift/drag than the upper rotor for the same relative airspeed, but since it is working in the higher airspeed downwash of the upper rotor, they match torque production at a hover setting (at sea level on a standard day, <yawn>). This designed so that minimal (ideally NO) yaw input is needed at a hover. During forward flight, this difference in lift production capability results in the upper rotor generating more lift than the lower rotor. The upper rotor rotates clockwise, so you get a net counter-clockwise torque from drag, thus the left yawing tendency at airspeed. This yawing tendency, left uncorrected, will result in uncoordinated flight which is messy and unprofessional. So, in a Kamov contra-rotating coaxial rotor helicopter, like the Ka-50, a Good Pilot, interested in maintaining steady-state coordinated level forward flight, will apply right rudder to counter the left-turning tendency of the upper rotor disk. In a conventional helicopter, applying pressure to a rudder pedal increases (or decreases) the pitch on the blades of the tail rotor, increasing (or decreasing) the lift they generate. The mounting of the tail rotor is such that lift from the blades directly translates to turning moment. So, pressing a pedal directly affects turning moment (aka torque) on the chopper. Unlike conventional helicopters, however, there is no tail rotor on the Ka-50. While removing moving parts from a design is usually a good thing, the function those parts served must be replaced by other parts, or else thrown out of the design. Yaw control is most certainly not an optional "feature" of a combat helicopter and the solution implemented in the Ka-50, while complicated, is quite elegant. In the Ka-50, yaw torque is controlled by varying the pitch of the blades of the two rotor disks. To yaw to the right, the pitch of the blades in the upper rotor disk is decreased which decreases lift which decreases drag which decreases the counter-clockwise (i.e., left-turning) torque it produces. If nothing else was done, the helicopter would yaw to the right due to the excess torque generated by the lower rotor disk, but it would also start sinking due to the loss in total lift. To counteract this, the pitch of the lower rotor blades is increased at the same time, increasing lift which increases drag which increases the clockwise (i.e., right-turning) torque it produces. The total change in lift is zero while the total change in torque is to the right. The process happens in the opposite for yawing to the left. This is all accomplished automatically by the helicopter control systems when the pilot stomps on a rudder pedal. This technique was apparently pioneered by Mr. Kamov, by the way. Unfortunately, that's not the end of the story. Due to a number of factors, including the fact that rotor blades are not infinitely stiff and thus flex a little, rotor blades slope upwards away from the rotor mast when the produce lift. This causes the rotor disk, which is essentially flat while making no lift, to form a cone shape, or rotor cone. In forward flight these cones are asymmetrical, even in single rotor disk helicopters, because of a phenomenon called "dissymmetry of lift". Dissymmetry of lift is caused by the fact that, on a helicopter that is moving, the rotor blades on the side of the disk that is moving in the same direction as the helicopter are moving faster through the air and thus generate more lift than the blades on the other side of the cone. More lift means more force pulling up on the blade, which means a steeper cone angle. Less lift means less force pulling up, which means a shallower cone angle. From the outside it looks like the cone is leaning away from the side of the rotor disk that is headed in the helicopter's direction. This side of the cone is generating more lift than the other (hence the handy-dandy "dissymmetry of lift" moniker) which creates a banking torque on the helicopter. In the Ka-50 contra-rotating coaxial rotor, the upper rotor is producing more lift overall, so although the lower rotor is producing a banking moment in the opposite direction, there is net banking moment to the right. So, in addition to the right rudder needed due to the differing torque production of the two rotor disks at airspeed, left cyclic is also needed to counter the dissymmetry of lift effect. Hence the left stick and right rudder we keep finding ourselves using to maintain straight and level coordinated forward flight. It's natural. And it's right. Now for the Dark Side: One of the cons of this design is that the cones of the two rotor disk system lean in opposite directions. This is because the two rotor disks spin in opposite directions. Although the upper rotor is a bit higher than the lower rotor, at a high enough airspeed, the two cones can cross, which, if you remember from Ghostbusters, is a bad thing: Dr. Egon Spengler: There's something very important I forgot to tell you. Dr. Peter Venkman: What? Dr. Egon Spengler: Don't cross the streams. Or rotor cones. Dr. Peter Venkman: Why? Dr. Egon Spengler: It would be bad. Dr. Peter Venkman: I'm a little fuzzy on the whole "good/bad" thing here. What do you mean, "bad"? Dr. Egon Spengler: Try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light. Or your rotor blades clashing at high speed and breaking off your helicopter, sending you spiraling to the ground! Dr. Ray Stantz: Total protonic reversal! Or rotor clashing! Dr. Peter Venkman: That's bad. Okay. All right, important safety tip. Thanks, Egon. To make things worse, since the lower rotor disk is working in the downwash of the upper rotor disk, its coning angle is more severe than the angle of the upper disk's. In forward flight the top rotor cones a little to the right, and the lower rotor cones severely to the left, bringing the tips of the lower rotor closer and closer to the blades of the upper disk. This is not an unanticipated aspect of the design. Mr. Kamov didn't have a maximum indicated airspeed warning system put in his attack helicopter to keep pilots from getting speeding tickets - he put it there to prevent the pilot from reaching airspeeds that cause intersecting cones. The system doesn't, however, take into account rapid increase of the collective at high airspeed (increased pitch = increased lift = increased coning = see Egon's saftey warning above). Stomping on the right rudder makes the upper rotor disk cone less, but the lower disk cones way more, further reducing the distance between the two cones. Throw in some cyclic controls in just the right direction and voila, rotor blade salad and lots of paperwork! The solution is simple: avoid high airspeeds! If you have to move fast, limit climbing to very gentle rates and avoid strong cyclic or rudder inputs in any direction. If you have a need to climb, pull back on the cyclic first while holding the collective steady. The helicopter will pitch up and start climbing without significantly increasing the rotor coning angles. As airspeed bleeds off slowly introduce collective to maintain your climb rate, but keep the total collective input low until the airspeed bleeds down. There's probably a table somewhere to help real pilots figure out what sort of climb rates they can get at high airspeeds before the rotors clash, but experimentation in DCS: Black Shark suggests you can comfortably climb/maneuver at speeds up to 225 km/hr without coning problems. At 225 km/hr and above, more and more caution is needed with the cyclic, collective, and rudder inputs!

Дима, ты не будешь против, если я твою идею вот в такую позу поставлю?

Представляю вашему вниманию новую кампанию «Республика». Для версии 1.0.2: http://www.digitalcombatsimulator.com/ru/files/155/ Англоязычный вариант. Немецкий вариант. Выражаю огромную благодарность товарищам Рустаму, Albacore, DS, dragony, Беркуту и DarkWandererу за помощь в озвучке. Кампания построена так, что её можно проиграть откатываясь назад по стадиям. Но с определённой (положительной) стадии откат уже невозможен по соображениям целостности сюжета. Кампания не является учебником по тактике, поэтому претензии что «вертолёты так не летают а танки так не плавают» не принимаются. Предупреждение! Все события, персонажи, границы государств и сами государства выдуманы. Территория выбиралась только исключительно из соображений максимальной пригодности к условиям миссий. Желающие поспорить о политике могут спорить в другом месте. Замечание по поводу контроля успеха миссий. Почти во всех миссиях для успеха обязательно приземлиться на указанной площадке. Но есть пару миссий, где очки начисляются по количеству и качеству уничтоженной техники, контролировать прогресс можно волшебной кнопкой «Э». Приятных полётов!

EDIT: Version 1.03 is released. You can download zip package from here http://www.lockonfiles.com/modules.php?name=Downloads&d_op=viewdownloaddetails&cid=188&lid=1367&title=RaMGen:%20Random%20Mission%20Generator%201.03%20for%20LOFC#dldetails or here http://www.filefactory.com/file/af3f8df/n/RaMGen103_zip Microsoft .NET Framework 3.5 is necessary to run this program. The component is available from Microsoft Update: http://update.microsoft.com/ RaMGen Features - Mission generator which can produce highly randomized mission every time. - Campaign system in which front line moves based on player's achievement. - Various types of mission tasks. - Numerous options of difficulty, weather, pilots, skins and weapons you can customize as you like. - Mod support on skin and weapon selections. - Map aspect ratio correction for wide screen monitor. Version 1.03 - A decimal separator problem on certain Windows localizations solved. - Russian version of Flaming Cliffs supported. - "Name" button to switch weapon names between the original and the modified ones.

Conveen: Maybe we can help you with Modman. Although Modman looks complicated it actually isn't when you install a mod. Download the mod, copy it to: C:\Games\ModMan\addons_dcs (Or wherever you have installed Modman) Run Modman It will say "Select game managment" Select "DCS series". Click "Apply" Click "Mods installer" You should see the mod in the main window already selected. At the top right find the button "Install" click it. That's it. Exit Modman and run the game as usual.

Thanks korrea :) Where is the server located?

Там ещё на фонаре видно окровавленные ошмётки

Уважаемые разработчики. По моему мнению (как авиационного инженера, а не эксплуатанта Ка-50) есть некотарая не точность или не доработанность с автоматами защиты сети системы электроснабжения вертолета, а именно: после запуска ВСУ должен быть и включатся выключатель типа "ГЕНЕРАТОР ВСУ НА БОРТ", который обеспечивает электропитание большинства потребителей для их проверки, устранение неисправностей и т.д. В противном случае у вас получается то, что до запуска двигателей и подключения генераторов двигателей на борт, электропитание систем и агрегатов осуществляется от аккумуляторов и преобразователя (если не подключать наземный источник питания). Но то, что вы включаете почти все, не один преобразователь и куча аккумуляторов не вытянут. ВСУ для того и устанавливается на борт, что бы обеспечить электропитанием большинства систем и агрегатов с целью их проверки работоспособности на земле, не запуская двигателей и при отсутствии наземных источников питания. Такой или подобный выключатель должен быть. С уважением, Andyustim.

Уважаемый andyustim Для наземных проверок нужно включить турбопривод, который будет обеспечивать потребителей гидравликой и электричеством. ВСУ ничего кроме воздуха, на Ка-50, не дает.

It contains -a lot- of interesting things! Thanks for sharing! I'd love to do something for DCS once the dev tools are released and this could be very helpful.

See if any of these threads contain a solution: http://forums.eagle.ru/showthread.php?t=40294&highlight=BlackShark.lua:198 http://forums.eagle.ru/showthread.php?t=39539&highlight=BlackShark.lua:198 If not, please elaborate on your hardware and software combination, including driver versions and any codec packs you have installed. Short version: I suspect you use an ATI graphics card, and have Catalyst AI active. Try disabling the latter or setting it to "standard". If that does not work, attempt a rollback to the 8.12 drivers. There are many known issues with the 9.x driver packages.

Maybe those are inflatable Rapors ;)

O_C, ознакомься Правилами Форума коль скоро ты их принял при регистрации.

Initial V3.0 released! Modman version only for the time being. Please let me know if you have any problems or comments. MIRRORS would be appreciated :) Link to the download on page 1 of this thread.

Мелкие противотанковые суббоеприпасы не приносят существенного повреждения кораблям, в тоже время ни одна из фугасных ракет установок Град в корабли не попала.

Best Buy sku# for BS: 9300302 It is easier when you call to give them the SKU then to tell them what it is and they have limited copies so call and they will hold it for you for a day. Hope that heps. Gunny

glad I went out and downloaded the english version , without a CD without a box, for MORE money that the actual DVD version....thats a little backwards, but o well. Now I too have a boxed version and the downloaded version.......:mad::mad:

Will have to go check my bust buy store

С 22 апреля 2009 г и ориентировочно по 28 апреля сервер будет остановлен для апгрейда. Вся дополнительная информация тут http://forum.aviasibir.ru/forumdisplay.php?f=3

If nobody knows nothing about future patch everyone would be happy flying this incredible simulator. The more i read and know about DCS work the best i understand why they are so cautious with the info they share. Keep working until " it´s done "

"True story of Black Hawk Down" Somalia 1993 http://tvshack.net/documentaries/The_True_Story_Of_Black_Hawk_Down/

Hello to all from a long-time-lurker! I find this discussion very curious and it is interesting that there is not total clarity even among the beta-testers how the system works in the KA-50 and in this simulation. Try this: With all three autopilot buttons on, lift off into a stable hover. Don´t trim from now on. Step onto the rudder. Turn 50 (or any other significant amount) degrees. Let go of the rudder. What happens next: The autopilot will yaw the helicopter back to the original heading. It is NOT aware that pilot input brought the new heading about, and it WILL try to yaw the helicopter back to the original heading all the time! Even when initiating the turn you need to overcome (try to just very lightly step on the rudder to try this) this, thats not dampening, that is fighting! I fly 737´s for a living (-300s and -500s), we have an autopilot mode called CWS, or controlwheelsteering. I think this is something like what Alphaonesix might be confusing with this Kamov-System when he says that the autopilot is aware of the pilot changing the parameters actively (without holding the trimbutton). Our CWS will allow you to steer the airplane with the controlwheel (hence the name) and once you let go, it will keep the plane exactly like it is (attitudewise) at that moment (within certain limits). This KA-50 autopilot will always try to fly you back to the pitch, bank and heading you had when you released that trimmerswitch last... So it all boils down to this: With the trimmer released, the autopilot is actively fighting to maintain the "set" parameters, against wind, turbulence, induced yaw, etc. AND the pilot. When the trimmerbutton is pressed, the pilot is free to maneuver the helicopter any way he likes it, without autopilot interference - and without autopilot assistance (not sure if there is "dampening assistance"). This system is just different to what most of us would be expecting, that´s where all the confusion is coming from. It´s a matter of personal preference, I guess, but if it works like that in the real KA-50 then by all means it should be implemented that way in this simulation - even if many, myself included, find it counterintuitive. Jan

It also switched off on an online mission today, was hovering rather hi and descending and must have entered the vortex, bloody thing was blinking away and the chopper started spinning. Survived that only to re-lock the SA19 I was targeting and watch it launch at me, came straight in through the canopy, CAPPOOOOF.