Mainly for Mav-JP - 12 degrees stick axes offset
-
@Mav, it turns that the SCC and stick are actually aligned properly, the internal SCC sensors however have the 12deg cw positioning. Is is logical due to the wrist joint with the physical arm positioning that if pulling back the stick will give a physical wrist movement to actually the ~7 o’clock axis.
This weekend I will be close to rl so I’ll find out more. Don’t completely count on the manual, specially -1, as to other details it leaves this deeper details in black, no need for the passenger to know more. One would need access to the FLCS maintenance ppl to find out the answers.
sorry but this makes no sense at all
in amraam picture, the whole stick is clearly rotated.
in the quotation of the dash1, it is clear that the stick is rotated, not the sensors.
and if sensors were rotated, what if you put roll only ? then you will have pitch mixing as well ? WEIRD !
-
Roll and pitch axes is rotated.
-
……and the Pitch transducers in the BLK 10 Stickbase is NOT angled those 12 degree, but they are in the BLK 52 stick base, …
The BLK52 has a digital FLCS with a rudder stability augmentation system (SAS)? And the BLK 10 has a analog FLCS without rudder SAS and it also has a larger vertical stabilizer? iirc.
So the stick sensor could be rotated to add roll to correct for rudder to roll coupling when crabbing, caused by engine gyroscopic forces during pitch change, is corrected by the digital FLCS rudder SAS. LOL, it sounds thin.
If the engine acts like a gyroscope, a force equal to the to the force that is applied to the engine to rotate is also applied to the axis 90* to the engine turbine axis. This is the yaw axis. So engine gyroscope effect causes the a/c to crab. The digital FLCS will correct this crab with rudder, the analog FLCS does not. With a rudder command, there is some roll compiling. Nothing in the FLCS solves for rudder to roll coupling(only has rate dampening).
-
@Mav, it turns that the SCC and stick are actually aligned properly, the internal SCC sensors however have the 12deg cw positioning. Is is logical due to the wrist joint with the physical arm positioning that if pulling back the stick will give a physical wrist movement to actually the ~7 o’clock axis…
Thiers only 1/4 inch of travel in the stick. Anything having to do with the arm’s rotary to linear motion wouldn’t be a factor imo if I’m understand you.
Also the arm rest is there to kept the pilot arm in axis. Is their a procedure that says the pilot need to set the arm set 12* to the stick?
-
Damn this here is getting technical but we like it… hehe
-
just seen some pics i took of a blk52+ and the stick indeed is leaning forward…
In my setup I have already applied it to my cougar instalation as for hardware… the solution is in the spirit of pistolero… tommorow i will post some pics and will check for software problems cause of force sensors…
-
The BLK52 has a digital FLCS with a rudder stability augmentation system (SAS)? And the BLK 10 has a analog FLCS without rudder SAS and it also has a larger vertical stabilizer? iirc.
So the stick sensor could be rotated to add roll to correct for rudder to roll coupling when crabbing, caused by engine gyroscopic forces during pitch change, is corrected by the digital FLCS rudder SAS. LOL, it sounds thin.
If the engine acts like a gyroscope, a force equal to the to the force that is applied to the engine to rotate is also applied to the axis 90* to the engine turbine axis. This is the yaw axis. So engine gyroscope effect causes the a/c to crab. The digital FLCS will correct this crab with rudder, the analog FLCS does not. With a rudder command, there is some roll compiling. Nothing in the FLCS solves for rudder to roll coupling(only has rate dampening).
dont know for block 10 but since block15, all FLCS (analog or digital ) have the same components (including SAS)
-
dont know for block 10 but since block15, all FLCS (analog or digital ) have the same components (including SAS)
As long as you don’t say digital AND analog FLCS.
The ECA was removed as a separate box and incorporated into the DFLCC for digital flight controls. The inverter/battery assemblies were also removed going from analog to digital FLCS.
-
This post is deleted! -
Advancing throttle on the ground for increasing taxi speed produces a right roll force that will drop the right wing few inches vs lift left side, and slightly turn the nose to the left. Small pedal inputs required to maintain a straight ride, except if you pull back throttle to idle and let the sufficient thrust to let move the bird.
On air this engine gyro effect is auto corrected by flcs.
-
On air this engine gyro effect is auto corrected by flcs.
I worked the F-16 for 19 years and never heard of this and also just double checked the FLCS CDCs. They don’t mention one word about FLCS adjustments for engine gyroscopic effect. The only adjustment it talks about for outside influences like this is the gun compensation logic.
-
Don’t know of the tech gizmos details or special documentation that you might have available, just the above link and a great hud/helmet vid with a sq commander describing this effect on ground, as it is happening on the taxi roll. I have mentioned this “feature” in the past too. (I am not 100% sure for the bank direction though, have to review it).
-
dont know for block 10 but since block15, all FLCS (analog or digital ) have the same components (including SAS)
I got a other stuff backwards.
The bigger vertical fin came on the later blocks for more stability when LANTIRN pod equiped . -
Don’t know of the tech gizmos details or special documentation that you might have available, just the above link and a great hud/helmet vid with a sq commander describing this effect on ground, as it is happening on the taxi roll. I have mentioned this “feature” in the past too. (I am not 100% sure for the bank direction though, have to review it).
Try re-reading what I wrote and go again. I didn’t say the effect didn’t exist. I stated that the FLCS training I got and the documentation I have doesn’t mention ONE word about it. Thus the FLCS is NOT auto adjusting for this. If it was there would be logic in the DLFCC that could possibly go bad thus requiring troubleshooting of the problem. The maintainers would know about it and it would be documented in CDCs, flight manuals, etc.
-
I worked the F-16 for 19 years and never heard of this and also just double checked the FLCS CDCs. They don’t mention one word about FLCS adjustments for engine gyroscopic effect. The only adjustment it talks about for outside influences like this is the gun compensation logic.
On a hard pitch command, if engine gyroscopic does effected the a/c it would be yaw if anything. This would create an outside influences in the yaw rate sensors, lateral acceleration and ADC. The same component that corrects for Dutch roll would try to correct of gyroscopic yaw. As everybody knows when you step on the peddles there is some roll (blank) not corrected by the FLCS.
Engine torque from delta rpms is another thing.
-
On a hard pitch command, if engine gyroscopic does effected the a/c it would be yaw if anything.
Hence why I don’t believe the effect is enough to alter course. If it were there would have to be compensation logic built into the FLCS based on RPM. If there were it is subject to errors and fails like any other electronic system in the aircraft so it would be talked about and explained in the CDCs, fault manuals, etc. I haven’t seen a thing and before today never even heard of this for the F-16.
The same component that corrects for Dutch roll would try to correct of gyroscopic yaw.
That would be the ARI helping to coordinate turns in the F-16. The only way you could use the same logic would be if the required yaw input would be the same or some relation/ratio could be developed between the two. It would also have to work in conjunction with the ARI for normal turns. Once again gyroscopic engine flight path correction is not mentioned at any point for the F-16.
As everybody knows when you step on the peddles there is some roll (blank) not corrected by the FLCS.
Correct. The system alters on rolls for adverse yaw (ARI or the “Dutch roll” as you put it) but not on yawing for roll effect.
-
I could not tell you anything about FLCS, DFLCS programing, etc. I have no idea how all works. I can not account for all FLCS/DFLCS corrections, but I never heard of gyroscopic engine effects affecting the F-16. Could it be there? Sure. I just never heard of pilot write up a F-16 for it rolling due to quick changes in RPM. I have trouble shoot many taxi “aircraft pull to the right” discrepancies. But they where caused by brakes, NWS, landing gear servicing, TGP, pilots and the NLG design. (wish according to the -1 could cause this effect dues to the " single fork" design of the NLG.
The single fork design of the NLG causes the
aircraft to drift right when NWS is not engaged. This
drift is easily controlled with rudder or differential braking.
Applying forward stick force during landing roll increases the
load on the nose wheel which increases the
right drift.In relation to the stick being rotated, never noticed, that is interesting.
-
That would be the ARI helping to coordinate turns in the F-16. The only way you could use the same logic would be if the required yaw input would be the same or some relation/ratio could be developed between the two. It would also have to work in conjunction with the ARI for normal turns. Once again gyroscopic engine flight path correction is not mentioned at any point for the F-16.
Correct. The system alters on rolls for adverse yaw (ARI or the “Dutch roll” as you put it) but not on yawing for roll effect.
I believe that ARI adds rudder to aileron inputs. No feed back loop.
To correct the Dutch roll, feedback from external and internal sensors is used to augment the rudder.
It’s the same component that corrects for slip/slide in a turn and allows the pilot to turn without using the rudder peddles.
-
In relation to the stick being rotated, never noticed, that is interesting.
let met get you up to speed.
They’re saying that stick sensors are rotated and not the grip handle for 3 reasons I guess. (There is a pic that looks photoshoped.)
1. arm geometry
2. easier to pull the stick when it rotated to the pilot. But some ppl believe that if that was the case the grip handle would also be rotated.
3. and my lame idea, it mixes roll command when a pitch command is made.Nobody can find any r/l doc giving a reason why the sensor assy. is rotated.
-
I worked the F-16 for 19 years and never heard of this and also just double checked the FLCS CDCs. They don’t mention one word about FLCS adjustments for engine gyroscopic effect. The only adjustment it talks about for outside influences like this is the gun compensation logic.
there is a roll rate feedback in the FLCS, so there is compensation for it.
Gyroscopic effect is very small (read NASA TP 1518), i decided not to include it, because the only value that i have is for 1 regime of engine and i dont know the correlation between engine rpm and gyroscopic effect
it is very very small effect though , just forget about it.
That does not answer my question; if you put roll , will it mix it with pich as well ?