Source
r/hoggit•
simffb

Spitfire question - pitot errors?

I bought the Spitfire these last holidays.

I noticed that the IAS and altimeter needles move a lot with the angle of attack like I've never seen in any other module or other flight simulator. I've been searching in the manual, the forums and reddit and I haven't been able to find any reference to this behavior, what surprises me as it really stands out when you see it.

Anyone knows if this is the intended behavior? Some kind of exaggerated pitot error model?

Edit: I mean, small pitch movements make the needles move in a way I haven't seen before. I'll post a video.

Edit: https://youtu.be/agUTjRi17qs

Posted Jan 7, 2020, 1:32 PM UTC · edited

1015
727Super27•

Altimeter errors make no sense since the pitot does not feed the altimeter. Only static pressure is relevant to the altimeter. IAS errors at high AOA are realistic, but to the extent you’re seeing, I don’t know.

7
nated0gePilot (Early Access)•

If he's pulling high AOA in say, a sudden vertical climb, it is possible for the altimeter to lag, aka hysteresis error.

That said, without a video to see what OP means by "moves a lot", its very hard to say with any definitive answer.

4
simffbOP•

I considered the video, but I thought it was too evident. Maybe there is something wrong in my side, so I'll make one anyway.

1
simffbOP•

Added short video.

1
nated0gePilot (Early Access)•

That looks very strange.

Im putting that one down as a bug. I can't think of any reason why an aicraft IRL would be showing that.

1
simffbOP•

Yes, I thought the same about the altimeter.

1
ShamrockOneFive•

I’ll have to go back and watch those more closely.

I do know the compass only effectively works in level flight.

2
simffbOP•

Well, that compass, it just doesn't make sense to me, and the manual isn't very helpful.

Edit: Ok, I have it figured out after some googling. Now I have to test the theory against the simulated one in DCS once I have the chance.

1
ShamrockOneFive•

No? I mean it’s not stabilized so it kind of makes sense that it might take a bit to settle down after some hard turns.

I tested the altitude and speed indicators and during anything involving any movement of the wings it definitely skews the readings. I’m assuming this has to do with rapid pressure changes.

I’m curious how other pitot tube systems handle this. It is quite rapid and extreme with the Spitfire.

2
simffbOP•

No? I mean it’s not stabilized so it kind of makes sense that it might take a bit to settle down after some hard turns.

Right. I wasn't considering that this compass is a normal compass so the needle points to the magnetic north, not your course.

1
topspin49•

The spitfire is an extremely pitchy aircraft. You need plenty of curves and a steady hand to fly it smooth.

1
InspectorHornswaggle•

Twitchy?

2
simffbOP•

Yes, is the only module where I'm using saturation on the pitch axis. But the needles thing happen with small movements. I'll try to post a video.

1
nated0gePilot (Early Access)•

IF you're keen to check, there is another pitot error that Im curious if modelled.

Check your IAS when banking left versus banking right; it should be ever so slightly lower when banking left.

1
simffbOP•

I'll take a look.

Edit: I can't tell.

1