aSnatchyConman

@desertowl is correct, IRL Viper can create HMCS/HUD markpoints in both NAV & A-G mastermodes, with the symbology/PVI being identical between the two MM's. The current implementation in game is either wrong or bugged. I'm leaning towards bugged because as it currently stands you can see the markpoint cue slaved to the HMCS LOS in the HUD but that disappears the moment that the HMCS LOS exits the HUD FOV (meaning that the cue appears to be slaved for at least a certain portion of the total player FOV). Source: reading a -34 and actually creating markpoints in the real jet.

Hey Hoirtel. Some additional info (if you're interested): - The loadout that's being flown in the videos is referred to as the "Sortie #6" config at Edwards. It has AIM-120's on STA 1/2/9, 300 Gallon Tank on STA 5, and a Targeting Pod on STA 5R (typically a Sniper pod because they cause more yaw instability than a Litening pod). - The Sortie #6 config is one of the most (if not the most) unstable configs you can fly in CAT I. It's used for training Test Pilots at Edwards prior to testing brand new, not previously cleared configurations or new flight control computer software. Due to how unstable it can be, it is only ever flown w/ a spin chute on the jet (in case the pilot can't recover from the post-departure deep stall/spin). There are other configs that are flown at Edwards for training. Sortie #1-3 are used for pilot fam and training CAF pilots to recover the aircraft in a benign loading. Sortie #4-5 are used for initial Test Pilot training (at USAF TPS) and are a little bit more "sporty" than #1-3. - In the Sortie #6 config, if you do the maneuver seen in the videos above (what is called a "slowdown turn" at Edwards), the nose will slide down (towards the earth, first video) as you depart controlled flight. If you do it in the opposite direction (to the left), the nose will slide up (away from the earth, second video). In DCS, this behavior doesn't seem to happen. The nose may move a bit, but not as it's supposed to from real-world observations. - Other maneuvers that are used to test departure susceptibility in this config are 1G, Elevated AoA Rolls (stabilized at 1G on the AoA limiter, ~26 AoA) and Max G Rolls (stabilized at the aft stick limiter in a turn and then rolling "over the top" while holding the stick against the aft "stop"). All of these maneuvers are done at ~35K ft and between 200-300 KCAS. In DCS, the FM doesn't seem to be able accurately recreate the Slowdown Turn yaw departure like is seen in the video, but I've been able to get a couple departures using Max G Rolls. Not quite as "violent" as what's in the video but somewhat similar. - Another factor (which Mover mentioned above) is that departures only really start happening when the CG is far enough aft such that the horizontal stabilators lack the authority to control the jet. If CG travel isn't modelled in the DCS Viper FM (i.e. if ED assumed a constant CG), then it may not be possible to effectively recreate the behavior seen in the video (since that maneuver was done at a CG that is close to limits, ~41% MAC). Hopefully ED can improve the High AoA FM in the future. It's definitely difficult to model since most post-stall behavior is nonlinear and not so easy to approximate. Hope this helps!

Fun fact: In addition to the "Departure from Controlled Flight" CAP that everyone is referencing above (Controls - Release / MPO - OVRD, then Stick - Cycle in Phase), there's an additional technique used in flight test to stop a spin. Unsure if it's modelled in DCS, but the Yaw Rate limiter in the FLCS is actually more effective w/ the MPO in OVRD. By going to OVRD and holding for a few seconds (depends on the severity of the spin), the horizontal stabilators actually help the rudder to arrest the yaw rate (via differential tail). Without going to MPO OVRD, they're pegged at max deflection (trailing edge down) due to the AoA feedback to the FLCS. If you just follow the CAP, it'll likely take longer to get out of the spin/stall because as you blend in full forward/aft stick, it removes the differential command and gives symmetric deflections for pitch rocking. If you purely follow the CAP in a high yaw rate spin, a lot of your pitch rocking energy is "cancelled out" due to the lateral-directional movement of the aircraft (see full 6 DoF Equations of Motion for as to "why" this happens). Pitch rocking is most effective when you are at less than ~20 degrees per second of yaw rate.

@bkthunder Not sure how to go about proving this but, I was the original poster on Reddit (u/espressoandcream). Appreciate you taking the discussion over here for the ED folks (glad that they're aware and investigating). Now that my account is actually activated on the ED forums, I'd be happy to help with any future data gathering/investigating. What can I say, my IRL job is flight testing F-16's. Makes sense that I do it in my spare time too. :D I'm pretty ignorant when it comes to flight models in DCS, but I can say from personal experience that something feels slightly "off" about the DCS F-16 when compared to real-world experience (hence why I was out doing the level accels that I mentioned on Reddit to gather data to compare to my own IRL experience). In addition to the obvious effects a bug like this would have on performance, I'm interested to see if there would be any trickle-down effects of using KEAS vs. KCAS, when it comes to stability & handling qualities. Probably not a whole lot at lower altitudes, but I can imagine there would be some noticeable difference up high. Hopefully I didn't open too big of a "can of worms" with this one. Thanks!

Cool post! I've had the pleasure to do some of this testing IRL on the Viper. Here's a couple things I can tell you (if you're interested in learning more): 1) Watch this video: https://youtu.be/Rv9YC-gaNYo. The maneuver shown here (and in the video from mvsgas's post) is a "break turn" or "slowdown turn". To check new flight control software, the jet is intentionally loaded asymmetrically (usually 2 AIM-9's on the left (STA 1/2), 1 AIM-9 on the right (STA 9), a centerline 300 Gal Tank, and a targeting pod). This loading makes the jet very "squirrelly" at higher AoA and causes it to be directionally unstable (yaw). To mirror what is done in the HUD footage, set your flight path marker (or velocity vector as those Hornet folks call it) ~5-10 deg, roll ~90 deg left or right, and let the nose slice to the horizon (while neutralizing your stick input). Once the FPM hits the horizon, apply abrupt full aft stick and have fun! Depending on what side you loaded the missiles on and what direction you rolled before the pull, your nose will either slice up or down because of the asymmetry and you'll depart. This is due to the rudder being "washed out" at high AoA and being unable to combat the inherent asymmetries present with a configuration like that. Sweet spot for stuff like this is >35K ft and between 250-300 KCAS (transonic, as mentioned in the video above). The jet won't always settle into a deep stall (i.e. falling leaf motion) and may sometimes recover by itself. But if it does, you have the recovery procedure more or less down. Throttle to idle, engage MPO, and cycle the stick in phase with the motion of the pitch oscillation. 2) The maneuver you described (while being effective at departing the jet) is not what was being shown in the videos (pilot does not make any roll input after the aft stick input). The nose movement is completely of the jet's own accord due to the asymmetry I mentioned above. However, there is another maneuver done in testing that is similar to what you're describing. It's called a "roll-coupled departure" and there's a really old video of one from the Blue Angels somewhere on the internet but I can't find it. Basically, a combination of full roll and pitch is input at the same time, held for ~270 deg of roll, and then the pitch stick is reversed. This causes inertial coupling and the jet can no longer keep up to maintain control. There are some other maneuvers done to test this stuff as well but all the cool videos come from the SDT's and Roll-Coupled stuff. 3) I've done a couple departures so far in DCS and the FM is close to real life, but not quite there yet. From what I can tell, it more resembles the Hornet's characteristics, with some tweaks for the Viper. Real Viper will totally get "stuck" in a deep stall/flat spin. In DCS, it seems like there's more of a natural tendency for the Viper to get stuck at limiter AoA rather than the full "falling leaf". Impressive FM'ing on the part of ED nonetheless. High AoA stuff is really cool and you get into some really weird flight regimes. Weird mechanics start to come into play so you start to experience some really "exotic" phenomena while testing this stuff like control reversals (i.e. left becomes right, right becomes left. Hopefully this was good info for you!