Avenger Strike Fighter
The Avenger Strike Fighter is an Imperial Navy close-range ground-attack aircraft meant for destroying armor and other heavy targets. It does this with the Avenger Bolt Cannon, the Strength 6 AP 3 Heavy 7 gun around which the flyer was built (also called the "Fuck Marines gun" because it ignores their power armor save and wounds them on a 2+), as well as 2 lascannons and 2 hardpoints that can mount anti-infantry or anti-vehicle weapons. Since it was supposedly used a lot by Sebastian Thor's forces during the Age of Apostasy, the Sisters of Battle see it as an instrument of divine vengeance (through superior firepower), so they use it a lot.
The Avenger model is produced by Forge World, released to coincide with Imperial Armour Aeronautica (the book containing the rules for it and other flyers, what with Warhammer 40,000 6th edition having flyer rules).
Forge World was very obviously inspired by the real-world A-10 Thunderbolt II (or "Warthog"), a ground-attack aircraft built around the tremendously powerful GAU-8/A Avenger Gatling cannon. It shoots 30mm depleted uranium shells so fast that it doesn't go "Dakka," it goes BRRRRRRT.
Though it's overall shape is akin to the F4U Corsair series even having the same iconic wing shape. Actually it's probably closer to a Ju-87 Stuka ; both have gull wings but the ones on the Stuka are more triangular, and is a ground-attack plane after all.
Like the modern A-10s cannon, the Avenger's gatling cannon isn't all that great against battle tanks and similar because 40k game mechanics don't use side armour to resolve hits from flyers like they do hits from barrage weapons. Just like modern ones, almost all 40k tanks (except siege tanks, like the Vindicator) would be side armour (AV10-12) on the top, and therefore quite vulnerable to the hail of S6 shots. That said, with the Strafing Run and Tank Hunter rules (the latter available only in the Horus Heresy version), its Gatling cannon is actually quite effective against AV 10 or 11 targets. Taking anti armor hard points though allows you flexiblity as you use the big gun for mowing infantry while the hard points take out armor.
|Forces of the Sisters of Battle|
|Command:|| Canoness - Ecclesiarchy Battle Conclave |
Ministorum Priest - Sororitas Command Squad
|Troops:|| Avenging Angel - Arco-flagellant - Battle Sister Squad |
Celestians - Crusaders - Death Cult Assassin
Dominion Squad - Retributor Squad - Seraphim Squad
Sister Hospitaler - Sisters Repentia
|Vehicles:||Exorcist - Immolator - Penitent Engine - Repressor - Rhino|
|Flyers:||Avenger Strike Fighter - Drop Pod|
|Saints:||Living Saint - Geminae Superia|
|Forces of the Adeptus Mechanicus|
|Troops:|| Combat Servitors - Electro Priest - Enginseer - Kataphron Battle Servitors |
Myrmidon - Secutarii - Skitarii - Tech Priest - Tech Thrall - Thallax - Ursarax
| Castellan-class robot - Cataphract-class robot - Colossus-class robot |
Conqueror-class robot - Crusader-class robot - Scyllax-class robot
Thanatar-class robot - Vultarax stratos-automata
|Walkers:||Ironstrider Ballistarius - Onager Dunecrawler - Sydonian Dragoon|
|Vehicles:|| Chimera - Galvanic Servohauler - Karacnos Assault Tank - Krios Battle Tank |
Land Raider - Macrocarid Explorator - Minotaur Artillery Tank - Ordinatus
Rhino Transport - Triaros Armoured Conveyer
|Flyers:||Avenger Strike Fighter - Lightning Fighter - Storm Eagle|
|Titans:|| Imperator Battle Titan - Imperial Knight - Reaver Battle Titan |
Warhound Scout Titan - Warlord Battle Titan