F16 Brakes at 4 35
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I have noticed the same thing. In 4.34, there was usually plenty of runway and you could get away with some lazy AoA’s. Now I have to work to ensure landing as slow as possible while maintaining AoA and as close to the threshold as possible. I have gotten into the habit of extending airbrakes as soon as I touch the ground, this also helps. Without a good AoA, the aerobraking does not give full effect either.
For last resort landings the hook is our new friend, I suppose.
Rather than landing as slow as possible, land on AoA. Touch down at 13 degrees AoA with the speedbrakes open to 43 degrees. After touchdown, hold 13 degrees pitch attitude until ~120 knots. Fly the nose to the runway, blend in braking, increasing to hard braking with the nose on the runway. As the nose touches down and you begin hard braking, override the speedbrakes, to the 60 degree open position (fully open). Apply full aft stick simultaneously for maximum aerobraking effect.
If you are having trouble controlling runway length while using that technique, what gross weight can you land at and just barely stop in time?
@Red:
Anti Skid does prevent wheel blocking but on dry condition makes braking distance a bit longer just like ABS on a car (at least that is my understanding)
ABS should not affect braking distance except in cases where the wheels would lock up, in which case ABS drastically decreases braking distance.
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I don’t mind the new changes, since it requires me to land more properly. Dee-Jay, you have probably always landed like a pro:-)
But for ABS (ie. anti-skid), would ABS not ensure the shortest braking distance possible, regardless of wet/dry condition. If wheels block, you slide longer ? I think that is the selling point for cars, at least
Also in aircrafts…btw. If I understood you correctly , you are right. Antiskid braking distances should be shorter than non-antiskid distances. That’s why it was invented.
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Thanks Blu3Wolf.
So… just try to use all the resources available, even speedbrakes at 60º.
anyway, my appreciation is that the aircraft brake capabilities have decreased in excess for dry runways
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Braking distance is noticeable compared to 4.34. But like in cars the ABS goal is there for that you can CONTROL the car (steering) or plane. If you lock a wheel you lost the control of the plane or car and you slide without control. But in some conditions where the ABS is very intrusive or the track conditions are bad is probably that the braking distance will be increased at the cost of maintaining control of the vehicle.
Regards
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Braking distance is noticeable compared to 4.34. But like in cars the ABS goal is there for that you can CONTROL the car (steering) or plane. If you lock a wheel you lost the control of the plane or car and you slide without control. But in some conditions where the ABS is very intrusive or the track conditions are bad is probably that the braking distance will be increased at the cost of maintaining control of the vehicle.
Regards
Please show me a video of a test where ABS caused an increase in max effort braking distance… if you lock a wheel you don’t just lose control, you lose braking effort also. Have a look at the mu of a tire in good contact with the road versus the same tire skidding.
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@Red:
disagree Dj,
braking is longer than 4.34. It is quite noticeable and I did notice it as well. But I put that on normal behavior for Anti skid
Anti Skid does prevent wheel blocking but on dry condition makes braking distance a bit longer just like ABS on a car (at least that is my understanding)Okay … I will do some tests.
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Dee-Jay, you have probably always landed like a pro:-)
More likely, I haven’t flown enough for months / years.
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Please show me a video of a test where ABS caused an increase in max effort braking distance… if you lock a wheel you don’t just lose control, you lose braking effort also. Have a look at the mu of a tire in good contact with the road versus the same tire skidding.
Once I saw a crew doing training at max effort landing dispatched without antiskid in a paved runway. First landing they made, two tires blew out. lol…
You are right, antiskid decreases landing distance always.
Airbus aircraft ANTISKID ON:
https://i.imgur.com/5SzqQdT.png
Same conditions ANTISKID OFF
https://i.imgur.com/XWvPmdx.png -
Please show me a video of a test where ABS caused an increase in max effort braking distance… if you lock a wheel you don’t just lose control, you lose braking effort also. Have a look at the mu of a tire in good contact with the road versus the same tire skidding.
It is absolutely “possible” to stop shorter without ABS then with, the downside is that’s it requires much more skill and a lot of practice so it’s only really useful for racing drivers and not pilots ;). The issue is that ABS isn’t perfect, Under normal ABS operation the tire locks for a fraction of a second, it is sensed by the wheel speed sensor and the the brake pressure is reduced, the wheel starts rotating at less then maximum braking effectiveness, brake pressure increases, wheel locks again, and the cycle continues, many times a second. An experienced driver can brake with a near constant force closer to the limit of grip without locking and produce more deceleration then the average of all the locking/unlocking ABS cycles.
That’s the physics of it, under all practical non racing scenarios ABS is the way to go because the margin for error is significantly bigger, and it deals with things such as unexpected surface grip etc much more easily. Non-ABS braking also requires a completely different technique to “Plant your foot, let ABS sort it out.” that most people will default to.
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Mav-Jp confirm me that, while working on Anti-Skid and runway surface conditions, braking action has been re-calibrated to better match the RL charts! (I didn’t remember that he actually told me that month ago)
… so yes … you are right guys!
No need to tests anything (I am happy I can resume my current task).
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yes
Brakes have been adjusted to match better real charts and all RCR
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Please show me a video of a test where ABS caused an increase in max effort braking distance… if you lock a wheel you don’t just lose control, you lose braking effort also. Have a look at the mu of a tire in good contact with the road versus the same tire skidding.
I said that in some conditions like snow or off-track ABS can increase the stop distance at cost of maintain the control of the vehicle, the alternative (ABS off) is worse because usually you dont have control of the vehicle and propably you will lost the control.
Regards
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Hi.
I ran out of runway at Kunsan after landing in very bad conditions. Landed the aircraft right in the zone, aerobraked and them hit the brakes hard. Ran out while still rolling at 65kts.
Then realized the thottle wasn’t at idle so I guess this one was on myself [emoji57].
Thank you for a great sim. It is an absolut joy fly it.Cheers
StokesSent from my iPhone using Tapatalk
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Once I had a similar situation like the test at 4:00 with half the runway covered with water (snow was melting from one side) on a heavy airbus a321 and you could feel the vibrations from the anti skid system on the fuselage.
Also it’s near impossible in heavy crosswind to apply anything more than moderate braking without some kind of ABS.
When you drive a race car or an F1 car then you can go ABS off and save a few milliseconds… IF you execute braking perfectly.
The difference between a perfect world braking and the computerized braking is not worth the risk.And aviation is all about minimizing the risk.
So now that we have a more realistic model it’s time to improve our approach-flare-touchdown. Even planning suitable runways based on weather, ac weight and airport runways length-equipment like real pilots do
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Question about the hook: I tried landing a near-perfect AoA (11-13 degrees) with hook out on final but it did not catch the wires until I was front wheels down (AoA=0), only then did it catch a wire. Is that as expected? If so, that is exactly opposite of carrier where you need the AoA>0 for the hook to come into contact with the wires.
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Once I saw a crew doing training at max effort landing dispatched without antiskid in a paved runway. First landing they made, two tires blew out. lol…
You are right, antiskid decreases landing distance always.
Airbus aircraft ANTISKID ON:
https://i.imgur.com/5SzqQdT.png
Same conditions ANTISKID OFF
https://i.imgur.com/XWvPmdx.pngOn most Airbus the procedure with antiskid off is braking manually with max 1000 PSI to avoid wheel lock,… so landing distance is increased.
You have to manually adjust brake pedals to brake less than 1000 psi, so that example is not valid here.
Flysmart just reflect that.Anyway, on cars normally ABS decrease braking distance as stated above, as a wheel locked has less friction coeficient.
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On most Airbus the procedure with antiskid off is braking manually with max 1000 PSI to avoid wheel lock,… so landing distance is increased.
You have to manually adjust brake pedals to brake less than 1000 psi, so that example is not valid here.
Flysmart just reflect that.Anyway, on cars normally ABS decrease braking distance as stated above, as a wheel locked has less friction coeficient.
Another argument to my point. The brake pressure is limited to avoid skid and have a better braking performance because pilots cannot notice if a long aircraft with fly by wire brakes is skidding. With full pressure would be even larger.
I can show the same effect on C130 777 manual (aircraft without pressure reductor) or F16 performance.
What some people are arguing here is that a human can improve the braking action doing it better than the antiskid computer. I really hope that they don’t believe that dynamic drag coefficient is higher than the static drag coefficent.
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Question about the hook: I tried landing a near-perfect AoA (11-13 degrees) with hook out on final but it did not catch the wires until I was front wheels down (AoA=0), only then did it catch a wire. Is that as expected? If so, that is exactly opposite of carrier where you need the AoA>0 for the hook to come into contact with the wires.
Not sure it is implemented but catching the 1st wire is not what you are supposed to do. It is not the same as in a carrier and catching the wire above a given energy may destroy the cable and/or the hook.
Land normally, aiming the threshold to maximize the LDA, perform optimal aerobraking until 100Kts, then drop the nose, ensure then points contact and lower the hook soon enough before reaching the last wire to catch it a slow as possible. -
So which is the conclusion ?, it is the same now braking with or with not antiskid in a normal condition runway ?