Jump to content

[TRACK REPLAY NEEDED]HUD speed way below steamgauge and both completely wrong


deadpool

Recommended Posts

Speed HUD: ~ 320 falling to 280kts

Speed Steamgauge: ~440kts falling

Speed ACMI: ~ 560kts

Pitch: -15°

Altitude 18000ft

 

Of course got the oscillations .. but I also noticed the discrepancy in shown airspeed.

 

Airspeed / mach indicator is entirely pneumatically (and rated for IFR) and shows indicated airspeed.

 

HUD might have been set to calibrated instead of indicated. Gotta check that.

 

So I thought it might be me being at around mach 1 at this speed, maybe they use different pitot tubes and there is some air pressure drop behind the front wave of air (stabilizer vs. stabilator, etc.) that's just hitting the static port or something ..

But it makes no sense .. it should then display higher numbers. And also static port and total pressure are on the same probe assembly in the F-16.

 

Also while the F-16 has two air probes, nose and forward right, afaik speed for both HUD and gauge come from the nose, side is used for sideslip, aoa, etc.

 

Steam speed is slowly dropping and HUD speed is 100kts lower and also drops at a different frequency.

 

Real speed according to Tacview (and otherwise observed aerodynamical behaviour) is close to 580kts where the plane just goes bonkers.

 

Then i thought .. was it icing? It is known to cause wrong low reads on the frontal probe in particular, but I did have the probe heat on and we haven't hit the clouds or anything where I'd expect sudden icing.

 

No FAULT lights were on for the FLCS.

 

The mission is over 2 hours long and it happened at the end, so I will save you guys the track file sadly.

 

What I can provide is tacview on request (or even track file). I did upload this to youtube under this URL:

 

Watch the first few seconds to see HUD and pneumatic steamgauge differ in speed and decelleration behaviour.

 

----------

 

If you look at another thread you will see this video:

 

where (according to external view the jet is at 1050km/h ~= 566 kts) and steam gauge and HUD are just showing wrong speed numbers.

 

BR,

Deadpool

 

- F-16 Testpilot -


Edited by deadpool

Lincoln said: “Nearly all men can stand adversity, but if you want to test a man's character, give him power."

Do not expect a reply to any questions, 30.06.2021 - Silenced by Nineline

Link to comment
Share on other sites

this is really weird man

 

 

found some videos of real F-16 having aeroelastic phenomena

 

 

crazy stuff but if this is connected to our issue... don't know.

Hardware: Dark Base Pro 900 | Asus ROG Strix Z790-E | Intel i9-13900KF | Kingston 5600 128GB Memory | 980 PRO 1TB NVMe "System" + 980 PRO 2TB NVMe "DCS" | RTX™ 4090 TUF | Silent Loop 360 AIO

Input: Logitech G15 + Roccat Kone + Virpil CM3 + Virpil Panel 2 + VKB Gunfighter Ultimate + Slaw Device RX Viper + Track IR + Valve Index
OS: Win11 Pro 64Bit

DCS Maps: All  DCS Modules: All

Link to comment
Share on other sites

this is really weird man

 

 

found some videos of real F-16 having aeroelastic phenomena

 

 

crazy stuff but if this is connected to our issue... don't know.

 

 

The video you linked is one of the reasons why they went on to put AIM120s on the wings to reduce the wing flutter at the expense or wear on the wings superstructure.

 

What we have is:

a) what looks like a too slow PID in the FLCS not correcting for oscillations.

b) something very weird with the speed instruments on HUD and steam gauge.

Lincoln said: “Nearly all men can stand adversity, but if you want to test a man's character, give him power."

Do not expect a reply to any questions, 30.06.2021 - Silenced by Nineline

Link to comment
Share on other sites

I still doubt that our issue is 1:1 connected to this topic. The oscillation occurs with different load layouts.

Hardware: Dark Base Pro 900 | Asus ROG Strix Z790-E | Intel i9-13900KF | Kingston 5600 128GB Memory | 980 PRO 1TB NVMe "System" + 980 PRO 2TB NVMe "DCS" | RTX™ 4090 TUF | Silent Loop 360 AIO

Input: Logitech G15 + Roccat Kone + Virpil CM3 + Virpil Panel 2 + VKB Gunfighter Ultimate + Slaw Device RX Viper + Track IR + Valve Index
OS: Win11 Pro 64Bit

DCS Maps: All  DCS Modules: All

Link to comment
Share on other sites

Can confirm that the pitch oscillations seem linked to this bug, whenever the mach meter starts getting off, the pitch oscillations follow relatively shortly afterwards. I probably will upload a vid of this happening.

Eagle Enthusiast, Fresco Fan. Patiently waiting for the F-15E. Clicky F-15C when?

HP Z400 Workstation

Intel Xeon W3680 (i7-980X) OC'd to 4.0 GHz, EVGA GTX 1060 6GB SSC Gaming, 24 GB DDR3 RAM, 500GB Crucial MX500 SSD. Thrustmaster T16000M FCS HOTAS, DIY opentrack head-tracking. I upload DCS videos here https://www.youtube.com/channel/UC0-7L3Z5nJ-QUX5M7Dh1pGg

 

Link to comment
Share on other sites

My track file sadly seems to be broken after a short while and would be over 2 hours long in total. Sadly not useful.

 

So, I can provide a track file if track file generation is fixed ^^

Lincoln said: “Nearly all men can stand adversity, but if you want to test a man's character, give him power."

Do not expect a reply to any questions, 30.06.2021 - Silenced by Nineline

Link to comment
Share on other sites

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...