A-10 Thunderbolt II FDM

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The A-10 Thunderbolt II

The A-10 Thunderbolt II, better known as the "Warthog", is a fixed-wing attack aircraft designed by Fairchild Republic and is operated exclusively by the U.S. Air Force (USAF). The aircraft is powered by two General Electric TF34-GE-100A This is a link to a Wikipedia article turbofans delivering 9,065 lbf (40.32 kN) each. The A-10 is straight-winged, with a wingspan of 17.53 meters. It can carry a wide variety of ordnance and payload, but is better known for its 30 mm rotary cannon affixed off-center in the nose. It has the only USAF aircraft ever designed solely for close support roles, and has proved itself on the battlefield as the ultimate ground support aircraft. The A-10 has 11 (8× under-wing and 3× under-fuselage pylon stations) with a capacity of 16,000 lb (7,260 kg) and the capability to carry the following payload:

  • Rockets:
    • 4x LAU-61/LAU-68 rocket pods (each with 19x/7x Hydra 70 mm rockets, respectively)
    • 4x LAU-5003 rocket pods (each with 19x CRV7 70 mm rockets)
    • 6x LAU-10 rocket pods (each with 4x 127 mm (5.0 in.) Zuni rockets)
  • Missiles:
    • 2x AIM-9 Sidewinder air-to-air missiles for self-defense
    • 6x AGM-65 Maverick air-to-surface missiles
  • Bombs:
    • Mark 80 series of unguided iron bombs or
    • Mk 77 incendiary bombs or
    • BLU-1, BLU-27/B Rockeye II, Mk20, BL-755[146] and CBU-52/58/71/87/89/97 cluster bombs or
    • Paveway series of Laser-guided bombs or
    • Joint Direct Attack Munition (A-10C)[147] or
    • Wind Corrected Munitions Dispenser (A-10C)
  • Other:
    • SUU-42A/A Flares/Infrared decoys and chaff dispenser pod or
    • AN/ALQ-131 or AN/ALQ-184 ECM pods or
    • Lockheed Martin Sniper XR or LITENING targeting pods (A-10C) or
    • 2x 600 US gallon Sargent Fletcher drop tanks for increased range/loitering time.

The A-10A will be the variant discussed here because that is the variant simulated in FlightGear.

A-10A

The A-10 has the tendency to lose center of gravity (COG) when the pitch is at its extremes. The aircraft cannot pull out of a harsh dive easily, nor can it climb quickly. At a level pitch of 0, maintaining 330 knots (kt), the pilot cannot simply pull back and hope to loop completely. The aircraft will stall at 120 kt and will continue to lose airspeed unless it is put into a dive to regain such. Once over 130 kt is reached, the dive must be leveled out, but the A-10 is slow to react in these situations. A full loop is not advised unless you have over 350 kt of airspeed to start with and all control surfaces are level—this includes flaps, spoilers, etc.

A snap roll is not an issue if the aircraft is lightly loaded and has reasonable speed. A minimum of 150 kt is required for a very quick snap roll. A slow roll requires level pitch and constant adjustments to keep it so, as well as an airspeed of 200 KIAS for a guaranteed safe roll. The A-10’s aileron systems are quick to react but if combined with faulty elevator levels it can be fatal.

The engines, once spooled to full military power, are relentless in their ability to pull the A-10 from the ground into the air. They are large and positioned out of the aerodynamic center (ADC), thus aiding in preventing excessive pitch moment (PIM).

Fuel is a constant worry. As it is burned the aircraft will regain its ability to perform maneuvers previously unreachable. Rolls and loops are now an option; however, it is necessary to maintain a throttle below the highest level—otherwise, the fuel consumption will be too high.

The weapon primarily used is the GAU-8 30 mm Avenger rotary cannon, capable of firing incendiary and depleted-uranium armor-piercing rounds. The cannon fires a fixed rate of 3,900 rounds per minute (rpm). It is the main weapon and is optimized for a slant range of 4,000 feet (1,220 m) with the A-10 in a 30 degree dive. Its accuracy is enough to place 80% of its shots within a 40-foot (12.4 m) diameter circle from 4,000 feet (1,220 m) while in flight.

The ordnance available in FlightGear is limited, and the best setup for ground attack is as follows (see the picture):

Notice the gross weight. This is your MTOW, or Maximum Take-Off Weight

Guidelines

  • Don’t pull fast on the stick, up or down.
  • When changing pitch, keep an eye on the P-ladder.
  • If it starts to buck when you nose down, pull up while jinking the stick from side to side, just slightly. That will pull you out of this problem.
  • If you’ve pulled up to high, then you will start to spin uncontrollably. This will be fatal in a matter of seconds unless you center the stick and jink the stick slightly in all four directions. Place throttle at 50% military power. Dive. Pull out sharply while not pulling to the extreme—that’s what got you into this situation.
  • When turning, you are liable to spin like the above situation unless you adjust pitch to slightly above the 0.0-degree mark while pulling to the side you want. It is essential that the pitch is constantly checked.
  • The A-10 also has a reaction system for the pitch—it takes a few times of pulling back to make a difference. If you pull back a little, it will make a minor adjustment, and a little more will do the same. But if you pull back a little farther, it suddenly pulls up sharply. You must be aware of this or you can end up bucking or spinning.
  • Firing the gun requires focus and zoom. Zoom in to the HUD so you can aim accurately. Come down at a 30-degree dive, preferably, and fire around 4,000 ft from the target. The aircraft will shake from side to side as the rudders attempt to automatically correct the recoil symptoms. You must also correct them, though, as it will significantly slow and even stall the aircraft if you fire too long. Fire in one to two-second bursts—never longer than three seconds; this is to avoid flight issues. It will also overheat the barrels if you fire too long, although this has not been implemented in FlightGear.
  • When firing the 30 mm, make sure to watch your round counter—it is in blue digits off to the left side below the HUD glass; it is below the switches board under the HUD glass.
  • To aim the MK-82s, switch from NAV mode to CCIP on the HUD dial, as you should already have done. CCIP will provide the same HUD but will include an aiming recticle. The recticle is a circle with a single dot in the center. The circle represents the max blast radius but, depending on the terrain, this might not always be the case. Never release bombs when you are close the ground. The CCIP only works when the correct angle is reached to drop the bombs point-first. This gets you rather close to the ground, and that can be hazardous. To avoid this, go full throttle, dive at a 15-degree slant, and drop as soon as the recticle shows up on the HUD. Of course you may want to make sure the target is in the sights before you release the ordnance. The MK-82s are free-fall iron bombs, meaning that they have no guidance systems in place to get them to their target. Instead, they go where you go. A few users on YouTube made the mistake of telling viewers to aim bombs with the velocity marker (the little crosshair circle that moves around), or VM, which predicts via computer where your craft will go next. This IS NOT true. Do not aim any ordnance with the VM. That will get you killed. It is worth it to train and understand that you won’t get it perfect on the first few runs. Strafing is difficult in regards to aiming a gun that moves the aircraft around, but aiming a free-fall bomb is even harder, depending on the terrain.
  • The weapons were mentioned to tell you about the flight dynamics, or FDM. When you release a payload, the A-10 will lurch to that side (unless you have activated Wings Level or something), and you will have to adjust. This can be treacherous if you are in mountainous terrain and can’t simply go where you want to. Think ahead what side will lurch and be prepared to compensate. LAU-68s won’t have as much as an effect, but releasing tanks or bombs will. Firing the AIM-9s depends on what mood FlightGear is in, and I have confirmed this with quite a few fellow pilots. HSOTF13, for example, fired the AIM-9s at a mountainside to relieve the A-10 he was flying (he was suffering engine failure and needed to jettison everything), only to discover that it did nothing to help. He was defenseless and falling out of the sky. In contrast, I fired an AIM-9 at a dummy airliner in a scenario. Knowing that it didn’t have an effect yesterday, I figured it would be fine. Flying at 14,000 ft and suffering a lurch to the left ended my mission—I had pulled too sharp and lost a control surface—the aileron, courtesy of Bombable. Thank you, Flug.
  • The weapons can be activated on the weapons panel under the Master Arm and Gun Rate switches. To configure your payload, go to Menu>Fuel & Payload.
  • The A-10 is a joy to fly once you have mastered the feelings and movements of this aircraft. Don’t play around—you will die.
  • Rule of thumb—know your limits, and know the A-10’s.
  • In the near future HSOTF will implement a better FDM, as well as expanding the payload, missile and bomb guidance, countermeasures, and gun rate. We will also try to implement the vision of the future—TV screens in FlightGear. The A-10 relies on these for targeting, but it is hard to do it by HUD alone in FlightGear.
  • Don’t EVER get into a dogfight. The AIM-9s don’t track, despite what they say, and you will die if you engage a fighter. Not only can they out-maneuver you, but they are equipped with weapons for fighting in the air. You are slow, not by any means agile, and, though you are designed for high-survivability, you will find yourself staring at the AIM-120 streaking at you.