Has anyone here looked into Warbirds?
It's really an excellent little game, and does a lot to capture the pulp feel of Crimson Skies. The world is well-developed- though not really that convincing- but is really just a thin veneer overlaid on an excellent system for fast and furious air combat. Converting directly from Crimson Skies to Warbirds wouldn't be without difficulty, but it could be done. Personally, I'd just enjoy the differences and build an entirely new fleet of aircraft for everyone.
Anyway, if you have $15, it happens to be on sale on DriveThruRPG and is really worth a look.
Another $2 will give you a small book that gives rules for running a more historic campaign with conversions of WWII campaigns.
In 1804, a 'strange storm' rips the islands out of the Caribbean and transports them to a mysterious new world where they float in the sky above a corrosive, abrasive maelstrom known as 'the Murk.' Parts of Florida and the Yucatan are also taken, and Cuba is ripped in two. The islands rotate around a constant updraft called 'the Eye' in three destinct levels. Apparently some of the surrounding landmasses are also torn off, forming countless hundreds or thousands of other floating islands which orbit the Eye in orbits that become increasingly eccentric as they move outward. Technology lags about 100 years behind OTL, meaning that in the year 2037 (setting start) that they are just approaching WWII tech levels. There are a few exceptions, though- radio and radar are hampered by the Eye. This means that radar is useless for long-range detection, and that radio communication is limited to very short range LOS sets (max 20 miles) and civil radio is more like cable TV without pictures.
Characters have three stats: Body, Mind and Spirit. These stats are neutral at 0 (zero); +2/-2 are the 'soft' maximums for most characters. These represent the folks up to roughly the 95th percentile of the population. A character can eventually build up to +3/-3... but these are extreme examples- like an Olympic Athlete with multiple gold medals, or a person who suffered horribly debilitating injuries in an auto accident.
BODY is, of course, how 'physical' your character is... but it is more a reflection of conditioning than brute strength.
MIND is how mentally aware characters are- this isn't just smarts, but also how witty and thoughtful they can be.
SPIRIT is a measure of the character's determination, devotion and charisma- the abstracts that quantify greatness.
All characters have a selection of 22 various skills across which they distribute 10 skill points, and two 'occupational' skills which start at 1 for free. Additionally, one of the skills is called your 'Knack' skill- you can roll two dice and choose the desired result, succeed or fail. A skill has a max rank of 6; again, things are 'soft capped' at 5 for most characters.
There are also lists of Advantages and Disadvantages- these work identically to the same mechanic in the Savage Worlds or Cortex systems, and must be balanced between the two. Like the systems I mentioned, they come in 'major' and 'minor' flavors- one major trait can be taken for two 'minor' ones or 'minors' can be taken on a one-for-one basis, up to a max of three.
AIRCRAFT CREATION (This is the part WE all care about... right?)
Designing aircraft is very simple and straightforward- unlike Crimson Skies you don't have to have much messy figuring to do... and you don't have to understand high-order mathematics to reverse-engineer the construction system to add your own little kinks. Warbirds (high performance fighters) have a basic template that represents an aircraft's three basic stats - Armor (3), Performance (3) and Structure (5). This template is then modified by a fairly extensive list of (IMO very appropriate) Traits to produce a unique chassis for your aircraft.
There is also a 'standard fighter' template that can be used for less capable military aircraft (such as those in national air forces) - Armor (1), Performance (2) and Structure (3)- which you can modify to some degree with Traits to produce the kinds of aircraft that your heroes will mow down by the bushel barrel, but which will still give unique 'flavor' to the aircraft they send down in flames. Additionally- and unavailable to Warbirds- there are 'national traits' which help these disadvantaged aircraft further flavor and combat capability, and which are developed around the specialties of a nation's pilots. (*1)
All rolls in the game are resolved by rolling a D6 and modifying the roll by the formula 1D6+STAT+SKILL+MODIFIERS. If the result is greater than the difficulty, then you succeed. In opposed checks with NPC's, the tie goes to the PC (because, dammit, the PCs are the heroes); in ties between PC's, you can either accept a tie or re-roll. These apply for all attack and skill rolls; skills all have an associated stat listed in their description, and attacks use Body as their stat.
Air combat is a bit special, as it uses 'Situational Awareness' - a unique stat that is the sum of all three of your character stats- and has four skills: Piloting, Strafing, Gunnery and Ordinance. NONE of these are used outside aerial combat, all start at 1 and they have their own pool of 2 skill points with which to advance two skills to 2.
There are also 'Reserves' - a pool of points that can be used on a one-for-one basis to augment rolls... either to help improve poor rolls or to achieve results beyond the character's maximum possible outcome. Finally, there is the 'Rule of Awesome' - when a character gets really gutsy/crazy/inventive with the description of their action, they can earn a bonus to the roll- +1 is recommended, but the book states that truly outstanding examples can occasionally warrant up to a +3 to the roll. Additionally, the action- if successful- grants the character +1 point to their Reserve and a bonus to their next roll of that type.
I've built a few characters and planes and tried a few mock combats and I like the system. It is simple and has several unique elements (especially in the air combat section) that make for interesting situations. My favorite is the mass combat 'Dogfight Tracker' - this handy accessory places planes according to their imitative, and lets players have an exceptionally clear view of the action. Basically planes are arrayed by initiative- lowest in front and highest in the rear- and the planes fire based on position on the chart. Planes further to the rear have 'advantage' over planes forward of them... and can pick ANY TARGET AHEAD OF THEM as a legal target for their fire. The plane in front, unfortunately, is totally screwed and can not shoot at anyone by any possible means unless it has a tail gunner- but it has to let EVERYONE shoot at it before he can fire.
(*1) I don't think that the devs give the national air forces enough credit for the capabilities of their planes... I suggest an 8 point build class called 'high performance fighter' [Armor (2), Performance (2) and Structure (4)] for more capable adversaries without having to field huge numbers of mooks.