Aircraft ASI doesn't show first 10kts

[Guest]

Have this issue with an aircraft where when taxiing, the ASI doesn't show the first 10kts of speed. Once I get up to 11kts, the ASI shows 1kt.The GPS notes the speed properly.Had this with a few aircraft back on fs2k, and now have it with one of the 747's I fly in fs02.Is there somewhere in the .air file I can fix this?(It's not wind, the panel, etc, it is the aircraft.)Thx.

[Guest RonB49]

I think that is normal expected behavior in a real airplane and "As real as it gets." To overcome the problem, I taxi with GPS on or click Shift+z to display the airspeed. R-

[Guest]

Hi there,The ASI is correct. It will NOT show any airspeed accurately at less than about 30 knots. Since the ASI relies on pitot pressure, this pressure has to build up by enough forward movement or ram of the aircraft. On larger airplanes the ASI scale does not even start below 45 knots.For taxiing puroses on small and medium size airplanes the official recommendation was (is?) 'a fast walking pace'. On widebody aircraft where the pilot sits so high that he cannot judge the taxi speed from the cockpit, a groundspeed readout from the FMS or IRS or INS is used to control taxi speed.Hope this helps.

[Guest]

Shift-Z shows 0 too until I get to 11kts, then it shows 1. It's actually this one that is more painful as I usually taxi in Spot view.Oh well, one of my aircraft is 'As Real As It Gets' and the rest, including the default aircraft, are not. Go figure ...

[John_Cillis 2,406]

While the comments are true of actual A/C airspeed behaviour, the way this is simulated by FS--some A/C will always leave the airspeed off by 10kts regardless of true airspeed, but it can be fixed. This is related to two entries found in the .air file, one of which "offsets" the airspeed indicator by a set amount, and the other which seems to influence the sensitivity of the Airspeed indicator. They come one after the other in the .air file, but sorry to say, I don't have access to Aired at my current location. I just know that the Airspeed offset should be at zero, and the other entry, which is usually a value of 28-29,000, should be adjusted to 32768 (a minus may be required--it's been a few months since I last updated these entries). I believe both are found in the Primary or Secondary Flight Dynamics section.I suspect when people examine their .air files, many will find that their favorite A/C is cruising and stalling around 10 ktas faster than specs. The reason--many flight dynamics authors are unaware of these entries. They build an .air file from another, and it has come to the point where every new A/C I was downloading for a while had these entries. The A/C designers would calculate their stall speeds, etc...., all the while unaware that these .air entries were skewing their real flight performance. This is especially true for most of the ultralight A/C released.... Many are stalling at 40kts and cruising at 65kts true, while only showing 30 and 55 indicated, even at sea level. It's because the designers never took the offsets into consideration when plotting the flight performance of the aircraft.-John

[Guest]

Now that's an answer!!!Okay, found the following using AirEd2000:1101 Flight DynamicsAirspeed Indicator Base=-10whereas a .air without the problem has this = 0As for another parm, what comes after it isWeight Factor?=-32768Both .air had this.So, changed A I B to 0, fixed my problem.Much appreciated!