The SIAI-Marchetti S.211 (later Aermacchi S-211) is a turbofan-powered military trainer aircraft designed and originally marketed by Italian aviation manufacturer SIAI-Marchetti.
SIAI-Marchetti started to develop the S-211 in 1976 as a private venture initiative, announcing its existence during the following year. On 10 April 1981, the first prototype performed its maiden flight. The Singapore Air Force placed the first order for ten aircraft in 1983. Some 60 aircraft have been sold to air forces around the world. Following Aermacchi's purchase of SIAI-Marchetti in 1997, the former has held the production rights to the type. An extensively redesigned and modernised derivative, the M-311 (since re-designated as the M-345) has been developed by Alenia Armacchi (now Leonardo), and is set to enter service during 2020.
A number of privately owned S-211s are operated around the world for leisure and advanced training. 

PRODUCT FEATURES

The design intent for the X-Plane version is to provide a simple, yet complete and effective light jet trainer for both military basic traning and fast-jet introduction.

The main features of the package are:

• Detailed external model for SIAI-Marchetti S-211

• Detailed virtual cockpit for both the pilot and the instuctor cockpits

• 10 different liveries including USAF and US Navy JPATS prototypes, Philippine Air Force, Singapore Air Force, Haitian Air Corps and privately owned aircrafts. 

• Resonably realistic flight model with custom airfoil data for the NYU/GRUMMAN K-1 airfoil fit for basic and intermediate military jet training

• FMOD sounds

• As bonus feature, the package also contains models for the M-311 and M-345 early prototypes, in 3 different liveries

At the moment of the initial release the planes do not support the X-Plane weapon system.

Also, some artistic licenses have been taken in the rendition of the backseat station so that, in the sim, the rear and the front seat are identical in terms of functionalities and controls, while in reality they are slightly different.

The package include two variants: the base S-211 model and the Aermacchi M-345 prototype. The M-345 has a simple representation of the digital avionic suit used in the prototypes, however the user cannot modify the configuration of the MFDs. In reality, serial production M-345 have been furtherly upgraded with touch-screen MFDs and all the analog instuments have been replaced by digital displays.

FLIGHT MODEL LIMITATIONS

The plane flight model has been developed for X-Plane 11.30 and above, and will work well with X-Plane 11.40 experimental flight model features.

The behavior of the wing has been modeled developing custom .afl on the basis of the real world data for the NYU/GRUMMAN K-1 airfoil. In general, X-Plane predictions seem accurate with respect to real-world in the 125-350 knots envelope. However, some deviations from the real-world data have been observed:

- rotation speed is 5-10 knots higher in the simulation
 

- maximum speed should be 400 kts for the S-211, but it is possible to go (slightly) above that in the simulation

- maximum speed for the M-345 is unknown, but the sim predicts 500 kts which seem excessive

- it is difficult to stall the plane as it will tend to go nose-down at high angle-of-attack, resulting in a speed increase and stall recover.

- very low speed behavior exhibit a nose-down tendency

- predicted stall speed is 5-10 knots higher than real-world

- real-world S-211 does not have nose-wheel steering; on the ground, the aircraft is steered by differential braking. We decided to include it for user-friendliness reasons.