Maximum rudder deflection without MPO engaged

saberrider · by **saberrider** » 16 Oct 2016, 07:53

Maximum rudder deflection without MPO engaged when You are in flat spin and high alpha?

vilters · by **vilters** » 16 Oct 2016, 17:16

What does the "P" in M P O mean? ? ?

Manual Pitch Override. => UP => Down freedom to "pump" the A/C's nose back down.

If my memory is still OK, the pilot looses ALL rudder control at somewhere between 25 and 29°AOA.

saberrider · by **saberrider** » 16 Oct 2016, 17:54

vilters wrote:What does the "P" in M P O mean? ? ?

Manual Pitch Override. => UP => Down freedom to "pump" the A/C's nose back down.

If my memory is still OK, the pilot looses ALL rudder control at somewhere between 25 and 29°AOA.

Correct so not much rudder deflection to stop the rotation .How you canceled at high alpha if you dont have any rudder deflection ?

basher54321 · by **basher54321** » 16 Oct 2016, 19:47

saberrider wrote:Correct so not much rudder deflection to stop rotation .How it is stop at high alpha if not rudder deflection ?

If you are talking about a flat spin e.g. as part of an inverted deep stall (50 - 60 degrees AoA) then the pilot does have (or did have) manual rudder authority to stop the yaw rate when inverted. No idea on the amount the rudder moves I would gather that info must be somewhere if you are trying to model it for a sim.

saberrider · by **saberrider** » 17 Oct 2016, 18:02

basher54321 wrote:
saberrider wrote:Correct so not much rudder deflection to stop rotation .How it is stop at high alpha if not rudder deflection ?

If you are talking about a flat spin e.g. as part of an inverted deep stall (50 - 60 degrees AoA) then the pilot does have (or did have) manual rudder authority to stop the yaw rate when inverted. No idea on the amount the rudder moves I would gather that info must be somewhere if you are trying to model it for a sim.

I'm interested about upright flat spin when airflow over the rudder is blanket by horizontal tail.

basher54321 · by **basher54321** » 17 Oct 2016, 19:52

saberrider wrote:I'm interested about upright flat spin when airflow rudder is blanket by horizontal tail.

AFAIK but don't take as gospel - the flight control system tries to counter the yaw rate when upright but doesn't when inverted (pilot needs to do it) - the fact that you can stop the spin at very high AoA with rudder means it is either not totally washed out or there are regions where the rudder has authority anyway.

I have no idea if it was possible to actually flat spin an F-16 outside of a deep stall due to the limiters.

vilters · by **vilters** » 17 Oct 2016, 22:18

Upright :
The pilot looses rudder control at 29°AOA. => the FLCS takes over to counter yaw automatically. (if at all possible for the flight position you are in)

=> The only way out is to use the MPO to "pump the nose back down". => Then start to recover when speed is above, well, initially above 100 kts, but fly with eggs in your hands. LOL.
=> But the good thing is => You "know" read that as "feel" when the stall breaks and the nose drops through the vertical.

Inverted :
Yes, you have rudder control, but do not loose time. => Pump that nose down ASAP ! ! ! !.
It does no good to hit the ground saying, "Yeah, but I got the rotation stopped".

Priority is => GET that NOSE DOWN => And get some air over those wings, then think about stopping rotations.

saberrider · by **saberrider** » 18 Oct 2016, 05:08

Thanks.From your replay I understand that the FLCS ignore pilot rudder inputs on the upright stall/spin but in upsidedown situation pilot have full and direct control of rudder maximum angles (30degrees).But how about use of flaperons (ailerons) and ARI assistance to break the rotation ?

saberrider · by **saberrider** » 11 Nov 2016, 12:02

basher54321 wrote:
saberrider wrote:Correct so not much rudder deflection to stop rotation .How it is stop at high alpha if not rudder deflection ?

If you are talking about a flat spin e.g. as part of an inverted deep stall (50 - 60 degrees AoA) then the pilot does have (or did have) manual rudder authority to stop the yaw rate when inverted. No idea on the amount the rudder moves I would gather that info must be somewhere if you are trying to model it for a sim.

Jbgator said about pilot full rudder authority only in UPRIGHT deep stall , with MPO activated , in this post-" F-16 report, help greatly appreciated."-from F16 general forum on page one.But I want to know without MPO how much FLCS deflect rudder since more+25AoA inhibit maximum deflection to pilot.