Angestoßen durch Marvel hab ich mich Heute mal etwas intensiver mit den Radbremsen der F-16 beschäftigt.
Unten angeführt ist der dementsprechend aussagekräftigste Artikel im Benchmark Forum
Ursache des Bremsversagens können mehrfache Ursachen haben und sind so auch simuliert. Hier geht es logischerweise primär um die Kräfte welche auf die Bremse bei der Bremsverzögerung wirken. Je schwerer die Maschine, umso mehr Masse muss gestoppt werden. Je schneller diese Masse dann noch in Bewegung ist, umso höher sind die anfallenden Kräfte.
Dementsprechend können zwei Regel beherzigt werden, insbesondere wenn in einem Einsatz mehr als eine Landung notwendig ist.
1. Leicht machen.
Bei einer kurzen Landestrecke z.B. Treibstoff ablassen, ggf. Zuladung vorher entsorgen.
2. Grundsätzlich erst unter 100 Knoten Speed (siehe Grafik) mit den Radbremsen bremsen.
Bei 100 Knoten Bugrad runter nehmen und anfangen zu bremsen.
Bei dem 1000 Fuß bis Ende Runway Schild sollte man allerdings bei geringer Zuladung nur noch maximal 100 Knoten Fahrt drauf haben, sonst reicht es nicht mehr...
Beherzt man dies, schafft man zumindest 5 Landungen mit intakten Bremsen.
Übrigens: 10° die Nase nach oben halten, also die F-16 als Luftbremse zu nutzen, zeigt tatsächlich Wirkung.
Zumindest im unteren Geschwindigkeitsbereich benötigte ich z.B. zur Reduzierung von 110 auf 90 Knoten 13 Sekunden mit der Nase 10° nach oben.
Nahm ich bei 110 Knoten bereits das Bugrad runter benötigte ich rund das doppelte an Zeit (ca. 26-30 Sekunden)
Es lohnt sich also die Nase oben zu halten.
Und natürlich fängt das ganze Bremsen mit der optimalen Aufsetzgeschwindigkeit an.
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Benchmark SIM Forum Threat
Ever do any silly landings on the highway strips in F4? You probably had to slam on the brakes just about immediately in order to stop. Well, you're not a C-17 doing an assault landing on 3500 feet of runway...Those days are over!
BMS now features modelization of the real F-16 brake energy limits. The limits are based on gross weight, temperature, pressure altitude and airspeed at which an abort (on takeoff roll) or braking on landing was initiated. It assumes idle thrust, maximum braking, speedbrakes are open, TEFs are down and applies to all drag indexes. It is now possible to experience:
· Blowing tire fuse plugs – tire(s) go flat which causes much more longitudinal friction and less lateral friction. Fusible plugs in aircraft tires are designed to melt at specific temperatures to relieve tire pressure and thus keep them from exploding.
· Brake hydraulic pressure line failures – brake reaction is reduced or lost completely.
· Main gear tire fire, hydraulic fluid fire, exploding tires & gear failure – the affected gear fails completely.
The four zones are modeled on a per-brake basis based on the following chart:
Zone 1 : Green: Normal zone – 0-11.5 million ft-lbs, nothing happens
Zone 2: Yellow: Caution zone – 11.5-15 million ft-lbs, 30% chance something bad happens
Zone 3 : Red: Danger zone – 15–24.5 million ft-lbs, 90% chance something bad happens
Zone 4 : Over 24.5 million lbs: Danger zone + immediate braking failureIt takes 5 – 9 minutes (random) for the brake energy / heat to build up after braking. During this time period is when one of the following problems can occur as described above, based on how much energy was built up. Brake energy is also continually monitored and built up during taxiing (when the brakes are applied obviously). Build up from taxiing is at its greatest with low gross weights and long taxis because the brakes must be used more often in order to control taxi speed. Taxiing with a gross weight of 20,000 lbs at 10 knots over a distance of 20,000 ft yields ~4.3 million ft-lbs of energy absorbed per brake. Heavier weight and increased speed uses less energy over the same distance (speed within reason of course). Heat and energy also dissipate over time. A rejected (aborted) takeoff with maximum braking followed by another rejected takeoff will likely put the aircraft in the danger zone or worse (all depending on the a/c gross weight, speed at which the brakes were applied, etc).
Related to this feature is the way the aircraft is taxied – this has been made more realistic. Like most aircraft, the aircraft may have enough thrust at idle power to start rolling (and accelerate), depending on gross weight. Therefore, unless the pilot holds the brakes or sets the parking brake, the aircraft will start rolling (again, depending on gross weight). If the aircraft is heavy enough, some thrust must be applied to start moving, and then idle thrust should be sufficient to keep the aircraft moving. Real world F-16 taxi and braking technique now applies which is:
Taxi speed in clear areas should not exceed 25 knots. To reduce tire wear, slow to
10 knots when making sharp turns. Do not ride the brakes. Correct braking technique allows
taxi speed to increase to approximately 25 knots, and then apply moderate braking to slow to
15 knots. Release the brakes, allow the speed to increase back to 25 knots and repeat the
process. Ground speed is available on the INS page (List 6).