Can the Viper recover from a flat spin?

[sacan]

Twin engine aircraft can shut one engine off and that should help slow the spinning, but in a single engine is not possible. Is there a method that is used to recover F-16 or any other single engine aircraft from flat spins or the solution is to eject?

[Ramsay]

I haven't tested the DCS F-16C but the usual method is to rock the nose (perhaps using manual pitch override) until it drops (IIRC takes 2 or 3 spins) until the pitch oscillations are great enough to cause the nose to drop. Once the nose has dropped and airflow is passing over the wings, you should be able to counter the rotation, allow speed to build in the dive and pull wings level.

 

AFAIK the real F-16C is fairly hard to induce a spin in unless you're unlucky in your weight and balance / asymmetric loadout or are deliberately trying to induce one i.e. flyby wire can protect 2 axis from departure, so deliberately departing in the 3rd axis to enter the spin.

Edited September 11, 2020 by Ramsay

[Frederf]

Yes, depending on the exact FLCS version and if you're inverted or not manual rudder entry may or may not be required. A flat spin is just a deep stall that's spinning.

 

In general you stop the yaw with rudder (or FLCS does it for you and you have no authority) first and then you recover from a non-yawing deep stall in the normal way you would recover from a deep stall. The Code One Magazine article Recovering From Deep Stalls And Departures by Dryden is an excellent source for that.

[sacan]

Thank you very much. The reason is that I fell from 23000 feet and was not able to recover from flat spin. In the end I had to eject because I was unable to get the nose down.

[jstnj]

I believe theres a momentary FLCS disengage switch that can be used in the real aircraft so that better control surface control can be given to the pilot in that situation

[Frederf]

Yeah to get out of a deep stall and yawing has been stopped hold the MPO switch against the spring to give you manual control over the tail to drive out of the stall. Otherwise at ~60 AOA the FLCS takes over and tries to put the nose down but it can't.

[DonH]

Add to the above:........Once MPO is engaged - at the point you see your nose pitching up then down - Pitch full forward (when the nose pitches Down) THEN - as the nose pitches back UP pitch for FULL back. Repeat and you will find at some point, the AOA reduces below the Critical AOA, you can then pitch for " just enough" nose down pitch - to build up enough speed to no longer be stalled. At this point, Don't pitch up. Just get back to level flight & flying speed THEN recover from whatever situation/attitude you recognize.

 

Keep in mind that if you have not recovered below 5000 AGL (In a deep stall)l - Eject. If you have not recovered (from a flat spin) below ~ 15000 AGL - Eject.

 

The above is my opinion and, for me, works in the Viper in DCS.

Edited September 14, 2020 by DonH

[SUBS17]

Thank you very much. The reason is that I fell from 23000 feet and was not able to recover from flat spin. In the end I had to eject because I was unable to get the nose down.

 

What did you do in order to wind up in that situation?

[sacan]

What did you do in order to wind up in that situation?

I went up vertically and when the Viper stalled I turned the rudder. The F-16 came out of the flight envelope and started falling like a piano. Zero airspeeds and uncontrollably :doh:

[SUBS17]

I went up vertically and when the Viper stalled I turned the rudder. The F-16 came out of the flight envelope and started falling like a piano. Zero airspeeds and uncontrollably :doh:

 

And you say that there was a horizontal rotation or was it a deep stall?

[Bouli306]

And you say that there was a horizontal rotation or was it a deep stall?

 

A spin is a deepstall with a higher than 30 degrees/sec yaw rate. But still it is a deepstall.

[sacan]

And you say that there was a horizontal rotation or was it a deep stall?

 

The plane stalled, lowered the nose but remained flat, level. It was blocked with the nose halfway down without being completely lowered. If I had managed to dive, I could have increased the speed, but it was blocked, going down flat and zero air speed.:(

[Frederf]

That's a deep stall for you. FLCS was commanding full nose down but at low pitch rates and full forward stab it can't continue the nose movement. The pilot procedure is to hold MPO and rock the nose "in phase" like pushing a kid on a swing until you can get the nose down into the flying regime again.

[Zergburger]

"The definitive guide to getting your dumb ass out of a deepstall (and other lessons)"

by

the senior experimental test pilot of the YF-16/F-16 program.

http://www.codeonemagazine.com/images/C1_SemperViper_1_1271449318_9999.pdf

[Bouli306]

"The definitive guide to getting your dumb ass out of a deepstall (and other lessons)"

by

the senior experimental test pilot of the YF-16/F-16 program.

http://www.codeonemagazine.com/images/C1_SemperViper_1_1271449318_9999.pdf

 

Old and in some cases obsolete. But a good read nevertheless.

[aSnatchyConman]

Fun fact: In addition to the "Departure from Controlled Flight" CAP that everyone is referencing above (Controls - Release / MPO - OVRD, then Stick - Cycle in Phase), there's an additional technique used in flight test to stop a spin. Unsure if it's modelled in DCS, but the Yaw Rate limiter in the FLCS is actually more effective w/ the MPO in OVRD. By going to OVRD and holding for a few seconds (depends on the severity of the spin), the horizontal stabilators actually help the rudder to arrest the yaw rate (via differential tail). Without going to MPO OVRD, they're pegged at max deflection (trailing edge down) due to the AoA feedback to the FLCS. If you just follow the CAP, it'll likely take longer to get out of the spin/stall because as you blend in full forward/aft stick, it removes the differential command and gives symmetric deflections for pitch rocking. If you purely follow the CAP in a high yaw rate spin, a lot of your pitch rocking energy is "cancelled out" due to the lateral-directional movement of the aircraft (see full 6 DoF Equations of Motion for as to "why" this happens). Pitch rocking is most effective when you are at less than ~20 degrees per second of yaw rate.

Edited September 19, 2020 by aSnatchyConman

[Frederf]

good tip