The Saab 91 Safir is a single-engine, two-seat aircraft designed and developed by the Swedish company Saab in the 1950s. It was intended to be a basic trainer and utility aircraft, and was the first aircraft developed by Saab after the Second World War. It has since been used for a variety of roles, including crop spraying, glider towing and aerial survey work.

The Saab 91 Safir was designed to be a simple and inexpensive aircraft that was easy to maintain and operate. It was also intended to be a rugged aircraft that could operate in harsh environments. To achieve this, Saab made use of readily available, off-the-shelf components and materials. The design was also kept as simple as possible, with few moving parts.

One of the things that Saab did well when designing the Saab 91 Safir was its use of lightweight materials. The aircraft was designed to be as lightweight as possible, making it easier to operate and maintain. The wings and fuselage were made from aluminum and the entire aircraft was constructed using rivets and screws. This combination of lightweight materials and simple construction techniques allowed the aircraft to be both strong and lightweight.

Another aspect of the design that Saab did well was the use of a simple and reliable engine. The aircraft was equipped with a Lycoming O-290-D2 engine, which was a reliable and widely used engine. This engine was simple to operate and maintain, and was also fuel efficient.

Where Saab could do better with the Saab 91 Safir is in the cabin. The cabin is cramped and not particularly comfortable, and the controls are not particularly ergonomic. In addition, the cabin does not offer much in the way of modern amenities like air conditioning or sound dampening. As such, it can be quite uncomfortable for passengers.

Finally, the Saab 91 Safir is not particularly aerodynamic and has a relatively low top speed. This means that it is not particularly suitable for long-distance flights or for high-speed operations.

In conclusion, the Saab 91 Safir is an excellent aircraft for basic training or utility operations. It is rugged and reliable, and is easy to operate and maintain. However, it does have some drawbacks, such as a cramped cabin and a low top speed. If Saab can address these issues, the Saab 91 Safir could be an even more successful aircraft.