Originally posted by Rolex
Skyraider A-1:

Skyhawk A-4:

You brought it up, DiabloTX.
If you made a mistake reading a "4" as a "1" then just say so. Don't just dismiss it as my confusion or error and say, "Sorry for hijacking the thread."
Either way, I'm done.
Skyraider derivatives: (notice AD-4B)
XBT2D-1 - Single-seat dive-bomber, torpedo-bomber prototype for the US Navy.
XBT2D-1N - Three-seat night attack prototypes. Only three aircraft built.
XBT2D-1P - Photographic reconnaissance prototype. Only one built.
XBT2D-1Q - Two-seat electronics countermeasures prototype. One aircraft only.
AD-1 - The AD-1 was the first production model. 242 built. (statistics in table)
AD-1Q - Two-seat electronic countermeasures version of the AD-1. 35 built.
AD-1U - AD-1 with radar countermeasures and tow target equipment, no armament and no water injection equipment.
XAD-1W - Three-seat airborne early warning prototype. AD-3W prototype, one aircraft only.
XAD-2 or BT2D-2 - Upgraded attack aircraft, one prototype only.
AD-2 - Improved model, powered by 2,700 hp (2,000 kW) Wright R-3350-26W engine. 156 built.
AD-2D - Unofficial designation for AD-2s used as remote-control aircraft, to collect and gather radioactive material in the air after nuclear tests.
AD-2Q - Two-seat electronics countermeasures version of the AD-2. 21 built.
AD-2QU - AD-2 with radar countermeasures and target towing equipment, no armament and no water injection equipment. One aircraft only.
XAD-2 - Similar to XBT2D-1 except engine, increased fuel capacity.
AD-3 - Proposed turboprop version, initial desigantion of A2D.
AD-3 - Stronger fuselage, improved landing gear, new canopy design. 125 built.
AD-3S - Anti-submarine warfare model, only two prototypes were built.
AD-3N - Three-seat night attack version. 15 built.
AD-3Q - Electronics countermeasures version, countermeasures equipment relocated for better crew comfort. 23 built.
AD-3QU - Target towing aircraft, but most were delivered as the AD-3Q.
AD-3W - Airborne early warning version. 31 built.
XAD-3E - AD-3W modified for ASW with Aeroproducts propellor
AD-4 - Strengthened landing gear, improved radar, G-2 compass, anti-G suit provisions, four 20 mm cannon and 14 Aero rocket launchers, capable of carrying up to 50 lb (23 kg) of bombs. 372 built.
AD-4B - Specialised version designed to carry nuclear weapons, also armed with four 20 mm cannon. 165 built plus 28 conversions. AD-4L - Equipped for winter operations in Korea. 63 conversions.
AD-4N - Three-seat night attack version. 307 built.
AD-4NA - Designation of 100 AD-4Ns without their night-attack equipment, but fitted with four 20 mm cannon, for service in Korea as ground-attack aircraft.
AD-4NL - version of the AD-4N. 36 conversions.
AD-4Q - Two-seat electronic countermeasures version of the AD-4. 39 built.
AD-4W - Three-seat airborne early warning version. 168 built.
Skyraider AEW. Mk 1 - 50 AD-4Ws were transferred to the Royal Navy.
AD-5 (A-1E) - Side by side seating for pilot and co-pilot, without dive brakes. 212 built.
AD-5N (A-1G) - Four-seat night attack version, with radar countermeasures. 239 built.
AD-5Q (EA-1F) - Four-seat electronics countermeasures version. 54 conversions.
AD-5S - One prototype to test MAD anti-submarine equipment.
AD-5W (EA-1E) - Four-seat airborne early warning version.
AD-6 (A-1H) - Single-seat attack aircraft with three dive brakes, centerline station stressed for 3,500 lb (1,600 kg) of ordnances, 30 inches (760 mm) in diameter, combination 14/30 inch (360/760 mm) bomb ejector and low/high altitude bomb director. 713 built.
AD-7 (A-1J) - The final production model, powered by a R3350-26WB engine, with structural improvements to increase wing fatigue life. 72 built.
UA-1E - Utility version of the AD-5.
Why is that so hard to understand???????