The Authentic Flight Model process was developed over several years, and uses a variety of professional tools to determine the optimal parameters for the .air file and aircraft.cfg file. Among these tools is a professional, virtual wind tunnel analysis system that calculates the wing and airfoil characteristics. Note: the Authentic Flight Model process is primarily directed at vintage propeller aircraft using piston and turboprop engines.
Authentic Flight Models are not created from a single system. Each one is carefully researched and put together the old-fashioned way, by "hand." Many hours of real-time flight testing in Microsoft Flight Simulator are conducted to confirm performance data and handling characteristics.
With this process, every aspect of the flight envelope is addressed. The top speeds at both sea level and altitude, as well as initial climb, will be correct, but so also will be the cruise power settings and cruising speeds, as well as fuel consumption during cruise. Both initial rate of climb and time-to-climb tests are performed, to confirm that the aircraft demonstrates accurate performance during the entire climbout, not just during the first few thousand feet. Stalling speeds, both in clean and landing configuration, are also accurately calculated. And although it is mostly eye candy, the temperatures and pressure will be in the correct ranges for both climb and cruise, and the use of the cowl flaps will create a realistic and desired result. A multitude of references are used to determine the aircraft's performance parameters.
The flight characteristics are also carefully researched and adjusted. Many hours of flight testing in all areas of the flight envelope are conducted to arrive at a satisfactory result. Areas such as slow flight and stalls, roll rates, and control response are examined closely and modified to create a flight simulation experience that is representative of the type of aircraft being modeled. This includes many trips around the pattern, cross-country, bad weather/instrument flying, and excursions to the aircraft's service ceiling.
The reason for this attention to detail has the goal of realistic flight planning. With an Authentic Flight Model, you can plan a cross country flight, calculating the rate of climb, fuel consumption during climb, cruising airspeed and fuel consumption during cruise, and expect the aircraft to behave and perform very much like its real-life counterpart. If you want to keep an eye on those cylinder head and oil temperature gauges, you'll find the needles pointing to the right place. When you change your climb speed by a few knots, you'll see those temperatures change. The entire experience is much more immersive when all aspects of the aircraft's performance are addressed in the flight model.
All Authentic Flight Models are set up to load into Flight Simulator with the trim already adjusted for takeoff. This duplicates the real world in the sense that the last person who flew the aircraft should have cleaned it up and made it ready for the next flight, and assumes the pilot has performed the checklist and made the proper adjustments to controls. Slight changes to the takeoff trim setting might be warranted with some aircraft depending on pilot preference. The Microsoft Flight Simulator Flight Dynamics engine is excellent, but there are certain limitations to the way supercharged engines are modeled. The simulator assumes the supercharger is always on, and allows no way of locking it out or decreasing the boost. Two speed supercharging is not modeled. The engine management procedures are correspondingly simpler than on real aircraft.
Good flight models can't be created in a vacuum. They need the smell of engine oil, old leather, 100 octane aviation fuel and the rush of air over aluminum or fabric-covered wings. They need the raucous, ear-splitting thunder of piston engines, and they require time at the controls of real aircraft. This author has committed to flying in as many vintage warbirds as possible, before that opportunity vanishes altogether. Thus far, these planes have been ticked off the list:
I make no claim to being a pilot of vast experience, having logged just over 40 hours at the controls of various aircraft. To compensate for my limited flying time, I have spent - and continue to spend - many hours interviewing the pilots who flew these types in combat, as well as the civilian pilots who currently fly them. This has helped to bridge the knowledge gap to some extent.
In the end, the flight simulator experience is purely subjective, as it should be. It's all about having fun. Hopefully, one or more Authentic Flight Models will allow a Walter Mitty or two to have just a bit more fun with the Microsoft Flight Simulator series.
Photo credits: All in-flight photos taken by the author.
Jay McDaniel
djm@airfiles.com