Dive/Dive Bomb FM Issues

[ChickenSim]

Supported a mission today as JTAC and noticed one of the Harriers broke apart in the dive after weapons release of 1xMk82 from a dive angle of around -20° at M0.83-M0.87 (540-565 KTAS).

 

Went back and reviewed the Tacview and I didn't notice anything out of the ordinary except that the Harrier was increasing AOA without increasing G past 1.9G in the pull-up maneuver.

 

One frame before departure/breakup, it was traveling M0.83 (548.3 KTAS), 1.9G, 12.4° AOA, and -11° pitch from M0.84, 1.9G, 11.9° AOA, and -11.8° pitch the frame before.

 

It was kind of entertaining from the ground and we all had a laugh, but given the Safe Escape Maneuvers for these aircraft are supposed to be 4-5G pulls at 500-550 KTAS delivery speeds, sometimes from dive angles as extreme as 45°, I am having a hard time figuring out what the problem is.

 

Was the 15 extra knots at weapons release really enough to disintegrate the aircraft, or was the asymmetry from a single Mk82 enough to depart it?

 

Clip from the ground (I was expecting 2xMk82s).

https://clips.twitch.tv/ShortBashfulTurnipSaltBae

 

Link to .trk file (40mb), breakup @ 55:42

https://drive.google.com/open?id=1QRtY3T7blRbuqKjIn12eHBNWab_iLXwM

 

Link to Tacview (11mb), breakup @ 55:42

https://drive.google.com/open?id=1vbgJmO48vfN3Gi2pyUuDifswG0rXN3J3

 

I've also seen similar behavior in public videos where pulling the stick @ >M0.81 seems to result in rapid AOA onset, slow G onset, and a subsequent departure.

 

 

Any clarification is appreciated.

Edited December 3, 2018 by ChickenSim

[Kula66]

I've definitely had an unexpected breakup when doing a relatively benign positive G manoeuvre when bombing ... unfortunately, I didn't record everything as you've done, but its certainly happened to me in the last week or so!

[Angus]

AV8B is a little touchy , but in the flight manual , we can see it dont love Negativ G's . in a dive you don't must to push forward your stick.

 

In pocket guide , Prohibited manoeuvers , see the graph , beetween mach 0.8 0.9 , AOA max 10 .

 

or 9) under 1 G for more than 15 seconds .

 

Maybe Flight model need more tuning , i dont know ;)

[ChickenSim]

Yeah i suspect the AOA is the trigger for the departure here, but the rapid onset of the AOA seems suspicious. With the SEM being what they are, you figure you've got to be pulling really hard to depart without some kind of contributing factor (high speed rudder input, loaded rolls, etc.).