[NO BUG] How make angle of attack of 45° in level flight？

The max angle of attack of approximately 35° in level flight.

I've been able to hit 42.2°:

I've been able to hit 42.2°:

In Stall Characteristics is AOA will stabilize at approximately 45° to 55° in AFCS, but AOA will stabilize at approximately 35° to 45° depending upon stores loading in DFCS.

Remember, the AOA in the Tomcat is not degrees, but units. an AOA of 15 units is roughly 10.3 degrees. So an AOA of 45 units will be approximately 30.9 degrees.

Remember, the AOA in the Tomcat is not degrees, but units. an AOA of 15 units is roughly 10.3 degrees. So an AOA of 45 units will be approximately 30.9 degrees.

Degree is used in Stall Characteristics of the NATOPS.

11.5.8 Stall Characteristics. The 1g level stall (maneuver flaps/slats retracted) is characterized by the onset of light airframe buffet at 12 to 13 units AOA. This increases to moderate intensity at 15 units AOA with essentially no change in intensity at AOAs as high as 60°. Buffet is not a satisfactory cue to determine airspeed or AOA during high-AOA maneuvering. The reduction in directional stability is apparent at 20 to 28 units AOA and even small control inputs will produce mild wing rock (±10° to 15°). Above 25 units AOA, lateral stick deflection causes roll opposite stick deflection. The stick should be centered laterally above 25 units AOA, and the rudder used to maintain balanced flight. Rudders are effective at controlling yaw and bank angle at all AOAs. Large rudder or lateral stick inputs produce an increase in AOA as sideslip increases. If deceleration is continued to full aft-stick deflection, AOA is equivalent to approximately 45° to 55°. The cockpit AOA indicator pegs at 30 units AOA, which is equivalent to approximately 25° true AOA . Pitch attitude at stall is between 10° to 20° above the horizon with no external stores and 10° to 15° below the horizon with maximum external load. Some longitudinal porpoising may occur at full aft stick.

 

Maneuver flaps and slats delay buffet onset to 13 to 14 units AOA and reduce the magnitude of buffet in high-AOA flight. Wing rock commencing at 20 to 28 units AOA is more severe (up to +25° AOB) and more difficult to damp with maneuver slats extended because ofthe increased dihedral effect.

 

The clean stall is defined as the application of full aft stick combined with rates of descent up to 9,000 fpm. As much as 5,000 feet is required for recovery from the fully developed stall.

In Variable sweep wing design：

Flight test experience with high-alpha control system techniques on the F-14 airplane：

Remember, the AOA in the Tomcat is not degrees, but units. an AOA of 15 units is roughly 10.3 degrees. So an AOA of 45 units will be approximately 30.9 degrees.

Now I'm getting curious. Isn't it linear? Because I suppose it's not.

Tape indicating angle of attack (AOA) on a scale of 0 to 30 units. (Equivalent to -10° to +40° rotation of the AoA probe.)

If it was linear, 15 units would be 15°. IIRC the on speed AoA is 12.8°, but I totally forgot where I picked this up (well, I read the NATOPS, the HB manual and this very forum, nothing else). Now you said it's ~10.3°...

And now the final, most daring question ever: Why on earth didn't they just use actual measured degrees? What's the deal with AoA units? Always thought this was something for those Air Force guys who can't cope with real units on their instruments... until I saw the Tomcat has those as well

I mean, there must be a reason, simply as that... and that question gets more interesting since it's obviously not even a linear conversion which means that 5 units of AoA are never the same amount of degrees depending on where you begin with

Now I'm getting curious. Isn't it linear? Because I suppose it's not.

 

 

 

If it was linear, 15 units would be 15°. IIRC the on speed AoA is 12.8°, but I totally forgot where I picked this up (well, I read the NATOPS, the HB manual and this very forum, nothing else). Now you said it's ~10.3°...

 

And now the final, most daring question ever: Why on earth didn't they just use actual measured degrees? What's the deal with AoA units? Always thought this was something for those Air Force guys who can't cope with real units on their instruments... until I saw the Tomcat has those as well

 

I mean, there must be a reason, simply as that... and that question gets more interesting since it's obviously not even a linear conversion which means that 5 units of AoA are never the same amount of degrees depending on where you begin with

search the WING ROCK MODEL FOR THE F-14A AIRCRAFT

Now I'm getting curious. Isn't it linear? Because I suppose it's not.

 

 

 

If it was linear, 15 units would be 15°. IIRC the on speed AoA is 12.8°, but I totally forgot where I picked this up (well, I read the NATOPS, the HB manual and this very forum, nothing else). Now you said it's ~10.3°...

 

And now the final, most daring question ever: Why on earth didn't they just use actual measured degrees? What's the deal with AoA units? Always thought this was something for those Air Force guys who can't cope with real units on their instruments... until I saw the Tomcat has those as well

 

I mean, there must be a reason, simply as that... and that question gets more interesting since it's obviously not even a linear conversion which means that 5 units of AoA are never the same amount of degrees depending on where you begin with

Probably to avoid that some onboard system has to deal with '0' and negative number, since the result could be wildly off.

-*-=+

0*10=0

At least thats how it is for the F-15.

Isn't it linear? Because I suppose it's not.

It's not linear. Partial chart at "Figure 2-83. Angle-of-Attack Conversion (Sheet 2)" in NATOPS.

Well those charts there show absolutely nothing on the relation of the actual angle vs the units indexed. They're showing AoA units at certain speeds in different configurations flying 1G for varying gross weights.

Well those charts there show absolutely nothing on the relation of the actual angle vs the units indexed. They're showing AoA units at certain speeds in different configurations flying 1G for varying gross weights.

Try harder. Last chart shows curves and dashed curves which are units vs true aoa.

15 units = 10.3° means it is not linear.. The formula is a bit more complicated, but personally I just go from there. (as there is absolutely no benefit to flying the aircraft knowing the degrees vs units. go by the units when you fly, and you will fly safely.)

Just to verify we're talking the same document...

At 35kft indicated pressure altitude and TMN 1.2, 50klb GW, 6 units equals 2 degrees. Otherwise same parameters, but TMN ~0.94, 4 units equals ~2.85ish degrees.

Well, that's level flight as well, but clearly shows that apparently there is no constant function (most probably there is, but it's very complex) of how to get either degrees or units out of the other. So to me, it's still sort of black box magic. My main question, which was "Why use AoA units at all where there is a unit called degrees after all?", still is kept being unanswered. The question if it wasn't linear was rathe rhetoric as it stands obvious it isn't anyway.

The only real reason I could imagine is this. But then again, why not just stay with degrees and stand to the point that there's a difference between measured and actual, just like it's in the cases of speed, altitude and even others?

(as there is absolutely no benefit to flying the aircraft knowing the degrees vs units. go by the units when you fly, and you will fly safely.)

This is true though and probably the essential thing here. It's just a question of understanding why there's a different scale at all.

Just to verify we're talking the same document...

 

At 35kft indicated pressure altitude and TMN 1.2, 50klb GW, 6 units equals 2 degrees. Otherwise same parameters, but TMN ~0.94, 4 units equals ~2.85ish degrees.

Yes.

Conversion is AOA true = (A0A units -3.715)/1.089 and at speeds below mach .4, AoA units = 1.0989 *(AoA true + 3.01).

Fwind already gave the right source.

15 units = 10.3° means it is not linear.. The formula is a bit more complicated, but personally I just go from there. (as there is absolutely no benefit to flying the aircraft knowing the degrees vs units. go by the units when you fly, and you will fly safely.)

But as FWind mentions the NATOPS manual states the AoA possible in both degrees and units:

"If deceleration is continued to full aft-stick deflection' date=' AOA is equivalent to approximately 45° to 55°. The cockpit AOA indicator pegs at 30 units AOA, which is equivalent to approximately 25° true AOA[/i']"

Interestingly it also mentions that wing rock doesn't occur with lateral stick inputs until at least 20 units AoA (ingame I think it starts already at 17 units?):

"The reduction in directional stability is apparent at 20 to 28 units AOA and even small control inputs will produce mild wing rock (±10° to 15°). Above 25 units AOA' date=' lateral stick deflection causes roll opposite stick deflection. The stick should be centered laterally above 25 units AOA, and the rudder used to maintain balanced flight. Rudders are effective at controlling yaw and bank angle at all AOAs."[/i']

But as FWind mentions the NATOPS manual states the AoA possible in both degrees and units:

 

 

 

Interestingly it also mentions that wing rock doesn't occur with lateral stick inputs until at least 20 units AoA (ingame I think it starts already at 17 units?):

The primary contributor to this roll reversal is the negative directional stability at high angles of attack (above 18 units at 0.9 IMN, and above 21 units at 0.15 IMN).

Lateral Control Reversal. Since roll control is provided by wing-mounted spoilers and differential stabilators, the aircraft exhibits proverse yaw throughout the flight envelope (yaw in the direction of the lateral stick input). At high angles of attack, several other aerodynamic and physical properties overpower the proverse yaw-to-yaw and roll the aircraft opposite the command input. The primary contributor to this roll reversal is the negative directional stability at high angles of attack (above 18 units at 0.9 IMN, and above 21 units at 0.15 IMN). The sequence of events causing this roll reversal is as follows (for the sake of example, consider a left stick input): ( 1) The aircraft initially rolls in the direction commanded (left); (2) As the aircraft starts to roll left, airstream direction relative to the aircraft changes from the vertical plane (plane of symmetry) into left sideslip (the definition of kinematic coupling); (3) Because of the negative directional stability, the aircraft reacts to the left sideslip by diverging in yaw to the right, further increasing the left sideslip; ( 4) Because of strong dihedral effect, the aircraft responds to the left sideslip and right yaw rate by reversing the roll to a right roll. The net effect in the eyes of the pilot is that, at high angle of attack, the aircraft responds to lateral control inputs by feinting in the desired direction and then rolling and yawing opposite to the direction commanded. For this reason, generous use of the rudders is recommended at high angles of attack in order to roll the aircraft. Roll SAS on during high-AOA maneuvering will aggravate the aircraft's tendency for lateral control reversal and will result in cross-control inputs during rudder-only rolls.

The primary contributor to this roll reversal is the negative directional stability at high angles of attack (above 18 units at 0.9 IMN, and above 21 units at 0.15 IMN).

Yes I know, but ingame wing rock seems to occur already at 17 units between 0.5 to 0.7 IMN, where it seems the NATOPS manual says it shouldn't start until around 20 units AoA in this region instead: "The reduction in directional stability is apparent at 20 to 28 units AOA and even small control inputs will produce mild wing rock (±10° to 15°)"

As for opposite stick deflection it says this doesn't occur until 25 units of AoA:

"Above 25 units AOA, lateral stick deflection causes roll opposite stick deflection. The stick should be centered laterally above 25 units AOA, and the rudder used to maintain balanced flight. Rudders are effective at controlling yaw and bank angle at all AOAs."

That said we also have the issue of wether the F-14B should be capable of 55 deg AoA ingame (AFCS) as the NATOPS manual states, as it's currently limited to around 42 deg AoA. That's a pretty big difference if indeed this is the case.

Yes I know, but ingame wing rock seems to occur already at 17 units between 0.5 to 0.7 IMN, where it seems the NATOPS manual says it shouldn't start until around 20 units AoA in this region instead: "The reduction in directional stability is apparent at 20 to 28 units AOA and even small control inputs will produce mild wing rock (±10° to 15°)"

 

As for opposite stick deflection it says this doesn't occur until 25 units of AoA:

"Above 25 units AOA, lateral stick deflection causes roll opposite stick deflection. The stick should be centered laterally above 25 units AOA, and the rudder used to maintain balanced flight. Rudders are effective at controlling yaw and bank angle at all AOAs."

 

 

That said we also have the issue of wether the F-14B should be capable of 55 deg AoA ingame (AFCS) as the NATOPS manual states, as it's currently limited to around 42 deg AoA. That's a pretty big difference if indeed this is the case.

The max AOA is around 50 deg in DCS.

The max AOA is around 50 deg in DCS.

I'm confused, you started this bug report by reporting the inability to reach the 55 deg stated in the manual. Now you're saying it can actually reach 50 deg?

For the record I can get 42.2 deg AoA at the most ingame. Only way to reach 50 ingame seems to be by sweeping the wings fully back at low speed and then yanking the stick back.

I'm confused, you started this bug report by reporting the inability to reach the 55 deg stated in the manual. Now you're saying it can actually reach 50 deg?

 

For the record I can get 42.2 deg AoA at the most ingame. Only way to reach 50 ingame seems to be by sweeping the wings fully back at low speed and then yanking the stick back.

the AOA of 50 deg is instantaneous, the AOA of 45 deg is stable.

The MAX AOA is 75-80 deg in Flight test experience with high-alpha control system techniques on the F-14 airplane.

the AOA of 50 deg is instantaneous, the AOA of 45 deg is stable.

 

The MAX AOA is 75-80 deg in Flight test experience with high-alpha control system techniques on the F-14 airplane.

This is unattainable ingame.

We1T-FxY9Bs

Units of Angle is a function of Angle of Attack and aircraft weight. This way, you can fly the same unit of angle on every landing and always have the correct angle of attack for whatever your aircraft weight.

Units of Angle is a function of Angle of Attack and aircraft weight. This way, you can fly the same unit of angle on every landing and always have the correct angle of attack for whatever your aircraft weight.

Nope. As already said AoA units vs degrees is just a conversion and has nothing to do with aircraft weight.

We1T-FxY9Bs

https://www.youtube.com/watch?v=Ci_Y_PLUnuI