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FM/DM threads Everything about FM/DM in CoD |
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2023-Dec-17, meanwhile 1C Entertainment and Team Fusion have published 'Cliffs Of Dover - Blitz' v5.040 and we are flying in a 24-7-365 virtual atmosphere that, at first glance comes very close to the German 'Normalatmosphäre nach DIN 5450' of 1937 [ref.1]. And what we have known as the International Standard Atmosphere for nearly 50 years [ref.2]. All in all, that's quite good for carrying out a few more airspeed tests ...
The 'Cliffs Of Dover - Blitz' v5.040 atmosphere If something that I'm writing is not clear, please leave a comment, and I'll do my best to make it clearer. The sea-level quantities of pressure, temperature, density, and the acceleration of gravity for Team Fusion -Blitz- atmosphere v5.040 are as follows: Quote:
air density Dh = { Ph : (Rair * Th) } = Dsl * { (Tsl * Ph) : (Psl * Th) } This equation formes the basis for numerous flight simulations, also for 1C-Maddox 'Cliffs Of Dover' v11.20362 … The altitude is given as geometric altitude (Z,m) as a function of metric length by Quote:
Here, we must make a distinction between the FMB geometric altitude (Z, m), which represents the actual 'tape measure metric' altitude above sea level, and the geopotential altitude (H, m), which is a pressure altitude consistent with the assumption of a constant value of gravity (g=9.80665) [ref.2], [ref.3], [ref.4]. Relation between geometric altitude Z,m and geopotential altitude H,m is Quote:
The 'Cliffs Of Dover - Blitz' v5.040 flight test If something that I'm writing is not clear, please leave a comment, and I'll do my best to make it clearer. I will continue to use the Bf109F-1 because there are reliable documents available regarding the performance and airspeeds of the warbird [ref.5] [ref.6]. To compare the 'TeamFusion-Bf109F' against authentic values [ref.5] following FMB script values are required: double geometricAlt = bf109f.getParameter(part.ParameterTypes.Z_Altitude MSL, -1); where <geometricAlt> reveales the geometric altitude as quantity in meters above sea level. double indicatedAirspeed = bf109f.getParameter(part.ParameterTypes.I_Velocity IAS, -1), where <indicatedAirspeed> reveales IAS as quantity in kilometers per hour (km/h), double trueAirspeed = bf109f.getParameter(part.ParameterTypes.Z_Velocity TAS, -1), where <trueAirspeed> reveales TAS as quantity in meters per second (m/s). double outerAirTemp = bf109f.getParameter(part.ParameterTypes.Z_AmbientA irTemperature, -1), where <outerAirTemp> reveales OAT as quantity in degrees Kelvin. The Patch v5.040 summer map tests with the Bf109F at 5004m geometric altitude above the Channel revealed the following quantities. Quote:
Quote:
Once pressure altitude has been determined, the density altitude is calculated using outside air temperature. Density altitude is formally defined as the “pressure altitude corrected for nonstandard temperature variations.” Quote:
Well, in a WWII single seat fighter the dynamic or impact pressure is the only directly measurable quantity that relates to the aircraft's speed with respect to the air. The Bf109F was equipped with the Bruhn Fl.22231 (60-750kmh) airspeed indicator [ref.6]. The airspeed indicator depends on the Fl.22261 Pitot-Static tube for its operation. The pressure generated by the Pitot tube for airspeed at current altitude is calibrated based on the relationship: dynamic pressure q = 0.5 * D * V². Doubtful that any WWII pilot has ever flown under so-called standard conditions. So, the German speed indicators were calibrated to density altitude DA+360 metres. Quote:
The Patch v5.040 summer map tests with the Bf109F-1 at approximately 5000,2 metres pressure altitude above the Channel should reveal the following data. Quote:
[1] Normalatmosphäre nach DIN 5450 (1937) [2] 1976 International Standard Atmosphere (PDF) [3] 1962 Manual of the US Standard Atmosphere (PDF) [4] 1940 Terrestrische Navigation (Ringbuch der Luftfahrttechnik (p.361-p371) [5] Kennblatt für das Flugzeugmuster Bf109, Baureihe F1 und F2 mit DB601N, Berlin 1941 [6] Fl.22231 - Bf109F ErsatzteilListe 04.1941 (JPG) [7] NACA Reference Publication 1046 - Measurement Of Speed And Altitude, Chapter III (p.25) [8] Standard Atmosphere Calculator [9] Airspeed Conversions (CAS/EAS/TAS/Mach)
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Windows 10 Pro 64-bit Intel Core i7-8700K CPU @ 3.70GHz 2x4gb DDR3-1600 GeForce GTX 970 4095 MB Logitech G35 Headset Logitech G940 Flight System (fw 1.42) Mad Catz Strike7 Keyboard Headtracker DIY 6DOF & OpenTrack 2.3.10 Last edited by Varrattu; 12-23-2023 at 10:00 PM. Reason: last reviewed: Dec-23-2023 |
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