MA-21 Aero Knight MS
Initial Release: Late Autumn 2004, Starter MA-21 (White)
Additional Releases: None.
Bit Protector - "Large Type"
Should be noted that BP Size Type on initial release is not consistent for every cycle of production or re-release. Being reproduced the following year could mean a different BP Size Type for a given Beyblade. In Aero Knight MS' case, it is unlikely it is anything but Large Type, since HMS wasn't in production long enough after its initial release to be re-released.
Attack Ring (AR)
Knight Crusher, ~22g.
Shares the same Metal Frame as Round Shell MS' Turtle Crusher.
Alongside Jiraiya Blade and Samurai Upper, Knight Crusher is one of the heaviest ARs in HMS.
Fairly square AR that has fairly well-exposed metal contact points that one would think generate large Smash Attack.
Unfortunately, Knight Crusher is for all intents and purposes a worse performing Turtle Crusher. It simply lacks the same power, and does not generate nearly enough Smash Attack to be considered even equal to Turtle Crusher.
Unusually weak performance considering on first inspection one would assume it would be powerful based on its blunt edges and heavy weight.
This is likely a result of the overbearing plastic around the metal frame making the majority of the contact with the opposing Beyblade, resulting in a legitimately unimpressive display.
Despite its lack of serious Smash Attack, it also has far too much recoil to be considered for use on Defense type combos, either, and is more prone to be knocked out than most other alternatives.
Best Possible Combo:
AR: Knight Crusher (Right-Spin)
WD: CWD Defense Ring (with Metal CWD found in RBA2)
RC: Grip Flat Core (Ultimate Version)
Game Plan: With a combo like this, given how ineffective Knight Crusher can be at times, it is best to put your all into ensuring your launch is perfect. Sliding/Catapulting or Banking with pinpoint accuracy to greatly improve your chances of landing multiple successive hits is ideal, since Knight Crusher isn't an AR that can take one hit and run with it, like Circle/Samurai Upper or Advance Attacker. If you must use Knight Crusher, this is the combo to use it on, since it simply cannot do well on either Defense or Stamina setups.
Courtesy of @DerexGT
Weight Disk (WD)
Circle Wide
See the Common Weight Disks page.
Running Core (RC)
Aero Core & Aero Wing, ~5g. (confirm)
The tallest RC in the HMS series
Similar to Plastics' Flying Defense AR, or Rock Bison's Normal Base, the gimmick of Aero Knight MS is a large circular propeller that while in practice cannot actually fly, much to everyone's disappointment, can generate some wind force.
With both Aero Core and Aero Wing together, the RC is also the widest available, and while in theory it would make an interesting low-recoil guard that keeps opponents a safe distance away from the rest of the Beyblade, it is not nearly stable or consistent enough to get anything but outspun or knocked out completely.
Lacks meaningful grip, exacerbated by the fact it is actually easier to push around thanks to the propeller's reach, without much pushback from any heavy components.
Without the Aero Wing, Aero Core makes for an equally interesting but largely useless RC that, while tall, is easily destabilized or removed from play without fail. Because of this, the propeller gimmick remains to be a gimmick that has shown its full, unadulterated potential in Beyblade.
Best Possible Combo:
AR: Circle Upper (Right-Spin)
WD: Circle Wide
RC: Aero Core & Aero Wing
Game Plan: This combo put the widest and most open-designed HMS parts together, since there is little way this RC setup can be truly competitive. It may be fun to play around with, and maybe not completely impossible to win casual matches either! Another potential option is using Phantom Fox's CWD Circle Attacker in Force Smash mode instead of Aero Wing and Circle Wide, to try and smash your opponents into the stadium with your tall RC. Equally entertaining, but tough to pull off. Also may not be legal since Aero Wing may be required on Aero Core at all times.