D4n Posted December 22, 2019 Author Share Posted December 22, 2019 Wow, thanks! From what country is that MiG-21-pilot friend of yours? :) DCS Wishlist: 2K11 Krug SA-4 Ganef SAM, VR-TrackIR icons next to player names in score-chart PvP: 100+ manual player-kills with Stingers on a well known dynamic campaign server - 100+ VTOL FARP landings & 125+ hours AV-8B, F-14 crew, royal dutch airforce F-16C - PvP campaigns since 2013 DCS server-admins: please adhere to a common sense gaming industry policy as most server admins throughout the industry do. (After all there's enough hostility on the internet already which really doesn't help anyone. Thanks.) Dell Visor VR headset, Ryzen 5 5600 (6C/12T), RTX 2060 - basic DCS-community rule-of-thumb: Don't believe bad things that a PvP pilot claims about another PvP pilot without having analyzed the existing evidence Link to comment Share on other sites More sharing options...
Jonne Posted December 22, 2019 Share Posted December 22, 2019 Hi Jonne, It is in the russian Mig-21Bis manual. The manual does not go into detail about what happens if you overspeed or exceed limitations, and it is not supposed to anyway. However, there is a graph in the manual that tells a lot about directional stability. It also says that directional stability decreases but remains adequate up to Mach 1.9-2.0 with two rockets or clean, and up to Mach 1.4-1.5 with one central droptank. The emphasis is on the word adequate. The whole reason for this is that the shock cone interferes with the airflow around the vertical stabilizer as you accelerate towards Mach 2. In real life, if the aircraft started to yaw and oscillate left and right lightly at these high speeds even before reaching mach 2, you had to abort the exercise and decrease speed. A friend of mine who flew this aircraft says he could only hit Mach 2 once or twice. Even though he attempted the max speed exercise countless times he had to stop before reaching mach 2 most of the time due to fuel constraints. A lot depended on atmospheric conditions like tropopause levels, temperatures etc, and it was easier to get to Mach 2 during the winter months. Here is the graph. Directional static stability coefficient against mach number: Thank you, that is really useful information. What you read form German MiG-21 pilots, the critical phase was acceleration above mach 1. The time you need for that step basically defines what top speed you will reach before your fuel limit. This itself was heavily dependent on how good the nose cone system was tuned. [sIGPIC][/sIGPIC] Link to comment Share on other sites More sharing options...
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