LJQCN101

IIRC the origin table is for a clean Su-27 weighting of 18920kg.

Hi, you can still find some of the ballistic tables from the old -34-1-1 or -34-1-2 manuals although the Combat Weapons Delivery Software has become the only single source for ballistic data since certain years, and those manuals became out of date. Examples for GBU-12A/B if you're interested to test it in DCS. Only level release data is included:

Hi, sry for late response. I only tested for the sustained turn and did fairly the same as yours. Yeah you have to make a perfect constant-speed level turn and at the same time monitor the fuel state so that you take a read on the G-loading at exactly 34% fuel. (my example) Strongly suggest you give it a try. I didn't find the SU-27 PFM much harder to fly. Just make good use of pitch/yaw trim to help pulling the stick and ticking rudders against sideslip. Regards.

3 to 5 m/s sink will probably result in a low glideslope. You'll often see an approximately 8m/s or 1500fpm sink rate IRL russian jets or F-18s. Examples: (-9m/s) (-11m/s) (-8m/s) (-10m/s) This is what I usually do: Watch my AOA indicator and fly an on-speed AOA plus a approx 3.5deg glideslope (or follow ILS guidance) with a sink rate of 7~9m/s. Keep that AOA and glideslope all the way to touchdown. Do not flare.

This is a fairly demanding feature when it comes to having marked and destroyed multiple targets and also finding the TAD way too cluttered. Dunno why such a simple function is not implemented in DCS A-10C. Not a criticism, just "hope". Ref. T.O.1A-10C-1

Just wanna share some info to you guys. I always found myself in a situation where my WCMD is in RDY status and my plane flying straight and level, but suddenly the alignment status changes to Degraded for no reason. That baffled me so much until I got a chance to read the B-52H manual. It says that you need to complete a Transfer Alignment (TA) process prior to weapon release. If you keep flying straight and level, the accuracy of TA begins to degrade. Probably the best answer found. Cheers. If you're interested in the WCMD, here's another issue regarding the wind correction for sub-munitions: http://forums.eagle.ru/showthread.php?p=2414489#post2414489

Tinypic link:

Correct for unguided bombs. However the INS/GPS weapons are able to guide themselves to the SPI position. The the wind data in LASTE -> WIND page will only change the release point of the bomb, it won't change where the INS/GPS weapon is going to hit (or dispense for WCMDs), if the release point is within optimum release zones.

This happens I guess:

We know that in current and previous versions of DCS A-10C, dropping WCMDs under crosswind conditions usually results in a burst right above the SPI location and the sub-munitions will drift far away from the target. The only option left is to manually correct the wind drift by moving the SPI to a upwind position. But there's some information about the WCMD found in the F-16AMLU M3 manual which states that the WCMD does have a wind correction function that will estimate the amount of drift of the sub-munitions and adjust the dispense point based on dynamic calculations of wind effect enroute to the dispense point. So I wonder if the A-10C will do the same thing IRL, and just not implemented in DCS A-10C? Cross-checked with B-52H manual that also stated the same:

Maybe you can provide some tracks for me to take over and see if it works. I'll make some videos for you.:thumbup: Another technique is just as what Thumper has suggested. Deploy anything that can induce drag such as landing gear, flaps and speed brakes. Similar technique can be seen in F-16 tested by NASA: "Trim" = deep stall trim, a particular situation in which an aircraft stays in a stable deep stall with constant AoA. In F-16's cases, deep stall trim point is near 60° AoA.

Youtube video added.

Maybe he means the strong tendency for the aircraft to zero out any bank angle. This is very obvious if you take a test on the spiral mode. When you bank the aircraft, a serious amount of side slip will build up, causing the aircraft return to zero bank angle. However if you manually apply rudder to counter any induced side slip, the aircraft will then perfectly stay on its current bank angle. Roll mode: you won't see obvious roll oscillation after rapid rolling, but it will take some time to completely zero out roll rate. Also, control response in lateral channel is not good enough (low on frequency). Dutch-roll mode: improved at low altitudes in DCS 1.2.12.:thumbup:

Let me clarify something about the AoA limiter. The AoA limiter of Su-27 will only limit the amount of stick input to a lower value. It doesn't have the authority to command nose down (stabilizer trailing edge down). The aircraft can still overshoot the 28-deg AoA limit at low speeds with stick in neutral position. It's easy to conduct an 1g-stall test to evaluate the performance of AoA limiter. Here's the test result of F-16 at an initial flight condition of 0.45Mach and 9144m. (Tests conducted by NASA) (δh>0 means stabilizer trailing edge down) As we can tell from the graph, AoA is gently limited to 25 degs even with a full stick-back command. (See gcom curve) The F-16 does pretty good in the test and the flight control system have the authority to command nose down. However Su-27 doesn't, and uncommanded pitch up is expected due to negative static stability. (Pitching moments increase with AoA builds up)

Actually you can still observe neutral speed stability in Su-27 above 780 km/h. Try this: Accelerate to 800 km/h and manually trim the aircraft to 1g level flight. Then accelerate and decelerate in a speed range of 780~980 km/h. Observe pitch changes.

For sure. I also got hundreds of questions to ask, but first let's just trust ED of what is done and what will be done to the flight model. As for the FCS longitudinal channel, to conclude: 1. The basic pitch FCS operates as a g-command system and mainly uses normal acceleration feedback to provide constant g per stick force, and to hold the flight path if the control stick remains in the same position. But this is not the final result and should not account for the overall pitch behavior. 2. An additional control law is added to the basic pitch FCS to imitate conventional plane stability. (Pitch up when accelerating and pitch down when decelerating.) Control logic is as follows: You spend all time trimming just because of that additional control law. It is not a inherent pitch behavior, but imitated. BTW, the static stability of a Su-27 without any control system is near neutral (+ - depends on actual CoG position - fuel and payloads) and the stick balance position is constant at speeds. (Credit: Yo-Yo)

Whole thread here: http://forums.eagle.ru/showthread.php?t=133600 I just concluded what Yo-Yo said. Maybe you'll find some useful info.

Maybe its because that the aircraft doesn't have any negative AoA/G limiter and if you push too hard, it will lose all pitch-up control effectiveness at around -25..-30 AoA due to some kind of flight characteristics. More discussion here: http://forums.eagle.ru/showthread.php?t=134028&page=7

Same question replied: http://forums.eagle.ru/showpost.php?p=2229658&postcount=22

Good info. Similar results can be witnessed in F-16 that you cannot control the negative longitudinal static stability even with a full stick command beyond a certain degree of AOA (without FCS). Actually I'm more willing to see a Pitching Moment (Cm) versus AOA (alpha) diagram for Su-27 at low speeds and high altitudes. Here's a Cm-α diagram of F-16 at 0.6Mach and 30,000ft. We can observe a loss of nose up control near -40° AOA, and also the efficiency of the elevator for nose up control is sharply decreased with AOA between -20° and -40°. I think Su-27 does pretty the same due to the similarities of aerodynamic design. And things turn worse at lower speeds. :thumbup: That's why the F-16 got a negative g limiter which uses AOA & airspeed as feedback to filter the pilot's forward stick command. In comparison it seems that the Su-27 won't limit any negative AOA build up.

That reminds me of a RL HUD tape of F-15 doing a tail slide all the way to inverted spin. Dunno his stick position while the aircraft is pitching down, but all we can learn is that , hmm, it is plausible.

I'm not quite sure but, according to what I've done in the cobra before, I don't even go nose-low if I pull the stick all the way back while the aircraft is pitching down. And here's a video of Su-30MKM doing tail slide where you can clearly observe the deflection of horizontal stabilizers. :thumbup: Thanks anyways, will try that later.

From a flight dynamics and flight controls point of view, this is a typical characteristics of an aircraft with a high lateral damping ratio and a low directional static stability.

Strongly second this. I'm aware that at low speeds and high AOAs, dutch roll does aggravate. According to my countless tests on the dutch roll mode at low speeds, with the activation of FCS (Flight Mode & Takeoff-Landing Mode), we can notice a slight enhancement at the dampening of yawing motion. However, I cannot see any changes regarding the rolling motion whether FCS is on or off. Frequent pilot-induced roll oscillation is still expected. As a typical 4th-gen FBW fighter, I don't think such control quality is acceptable by the FCS control law designer or the air force. Anyways, two of my friends just got contact with in-duty Su-27 pilots, hope he can bring us some good info. (One of them is working in a flight test center and can easily acquire feedback from the pilot. I've shown him a series of control & stability tests of DCS Su-27, and he seems a little bit upset about the rather high longitudinal dampening ratio under Takeoff-Landing Mode, poor lateral-directional stability and high lateral dampening ratio, not to mention the departure susceptibility. He also holds the point that an aircraft with such quality all together as I listed above won't even be approved to be put into production.)

Press the pause key first.