STT speed reading

Hi,

Sorry if this was already asked/clarified, but did not find it.

I was practicing AAR, and locked the tanker in STT from distance to get its speed and closure rate. Closure rate seems ok, but the speed showed to be 390kcas???? I did then check the mission details (F-16 instant action - aar) and it said the tanker would fly 270 knots which I verified to be true in the end...but my radar keeps fooling me. Am I doing something wrong? Adding to the offense, the tanker tells me it is at angels 23 when in fact it is flying angels 25... so all in all my first approach was a disaster: flying too fast and low until I was near the tanker and then a festival of overcorrections :(

On a different topic...is NCTR implemented (non cooperative target recognition)?

Sounds like you’re looking at TAS and not IAS

It might be that the tanker is giving speed over the ground, not the indicated airspeed. As for the altitude, make sure you're using the correct barometric pressure setting.

Also I've noticed in dcs the tanker seems to give an altitude about 1000 ft too low. Maybe it rounds 24900ft down to 24k ft or something.

Sounds like you’re looking at TAS and not IAS

According to the Early Access manual, should be callibrated airspeed, and I made sure my HUD speed was also callibrated:

The MFD display in STT mode remains much the same as RWS mode with these differences: The locked radar target is displayed as a circled triangle symbol with a flight vector line. The target’s altitude is displayed below the target symbol. The top of the display shows aspect angle, ground track, calibrated airspeed, and closure rate.

"Calibrated" just means that the data is interpreted. Calibrated Indicated Airspeed (CIAS) refers to the speed interpreted by a dynamic pressure gauge on an aircraft which may give inaccurate readings due to high AOA or something. "Calibrated" is just "corrected." This is the only form of calibrated airspeed I'm familiar with, so it may just be weird manual verbiage.

If I had to guess, what the manual means by "calibrated" is some variation of "speed over the ground." If you have on your radar many targets at many altitudes going many different ways with various winds aloft and wind shear, then reporting the speed through the air (IAS, TAS) isn't going to be as helpful as giving all the targets a speed over the ground.

And the data might further be calibrated such that it gives the aircraft speed in a climb what it would be relative to the ground in level flight (So an attacking mig21 10k ft below and 5 mi in front would show up as coming at you at 500kts rather than 200kts over the ground.)

As for the altitude thing, I dunno, it has been generally sketchy for me as well.

Calibrated airspeed has a specific definition. It's almost exactly IAS with corrections for imperfections in the instrument and where it's mounted. In most cases it in the F-16 the difference is tiny especially compared to IAS/CAS to TAS.

The FCR displays a heavily calculated number which is its best guess of what the target's IAS/CAS should be.based on the relative position and velocity, own ship wind drift, etc. The idea is that target IAS/CAS is more tactically important than TAS.

Be aware DCS AI fly true speed and true altitude in most cases. Your altimeter might not be so close to the F2 info bar value due to temperature or pressure effects. That's normal.

Sorry guys but I'm new here, I don't see any were to start a new posts can you help me out.:lol: