JF Canberra SP3

[Dev One]

Just my general observation of this phenomena (ASI jerkiness) in FSX + Acc, thats exactly what I get if I set my weather up with turbulence & with any wind shear. Most unrealistic. I don't do real weather. This happens to me with any model, so it might not be a JF thing. I do notice though that there can be turbulence down low that is random, but associated with the terrain.
Keith

[DaveG]

There's probably not any damping or lag in the code for the ASI needle animation, so it jerks around responding to any change instantly rather than smoothing it out. It's easy enough to do, but as the code is built in to the model it's not something that can be altered without re-compiling the model. (well, there are ways, but it gets complicated! )

[Dev One]

DaveG, If I read you correctly re: damping of the needle, I've just looked at my own ASI .xml that I created & find it has a delay of 360 degrees per second. Don't know about the JF one of course!
Keith

[cstorey]

I have never even had FSX so I cannot comment on the specifics, but in answer to Paul's concerns about whiplash , the ASI behaviour he notes is not unrealistic in gusty/shear conditions, but it will never in reality result in the aircraft suffering marked acceleration or deceleration because of its very considerable inertia . It is the fact that the a/c keeps moving through space at a fairly constant rate which causes the ASI needle to fluctuate. If the a/c suddenly encounters a gust from ahead it does not suddenly slow down in space : if it did, the ASI reading would stay constant. What happens is that the a/c continues on its way in space, but the gust shows up as a marked flutuation in the airspeed reading .

Another point which someone made is that there are no corresponding fluctuations in the pressure instrument readings, which normally one would expect in such circumstances , but a. these instruments in real life have a considerable amount of lag/damping built into them, and b. the modelling of static vents on flightsim a/c is no doubt quite different from real life

[Dev One]

From the reality point of view, I know from Jindivik development that the lag was quite important in determining the autopilot response, obviously to gusts when one it travelling at about 500 knots. (And I think one of the problems with the Sea Vixen drone autopilot suffering pressure change at transonic/supersonic speed & its affect on the altitude hold system). But on the other hand I do not think that a sharp windshear actually exists as modelled in FSX, (unless one hits a supersonic shock wave coming in the opposite direction!). I must admit that I have not seen in real life such a sharp response to airspeed. As far as static vents go I'm sure that there would be an even slower response, or none at all (which is the object of location of them) compared to a pitot tube, otherwise VSI & Altitude readings would be impossible to monitor!

Would be nice though to be able to slug an ASI sufficiently.
Sorry if I'm going ?
Keith

[Paul K]

...but in answer to Paul's concerns about whiplash.. If the a/c suddenly encounters a gust from ahead it does not suddenly slow down in space : if it did, the ASI reading would stay constant. What happens is that the a/c continues on its way in space, but the gust shows up as a marked flutuation in the airspeed reading .

Of course ! Hadn't thought of that - thanks Chris, good explanation.

[Airspeed]

....................
Would be nice though to be able to slug an ASI sufficiently.
Sorry if I'm going ?
Keith

Keith, if THAT's off topic, I'd better stop posting altogether.

[DaveG]

Just a quick HU, JF have released SP3.2 for the Canberra now.
Nice to see continued updates to a 2+year old release.

[DaveB]

Cheers Dave

Downloaded but not yet installed. It's in a queue along with the B17 and MV Phantom updates
ATB
DaveB