Editor’s Choice – Antonov AN-2
At AircraftSales.US, we love airplanes! We love looking at airplanes and we get to see hundreds every week. Once in a while, we come across some that we fall in love with, some that we think are a really good deal, some that we REALLY want to fly, and some that are just strange. The AN-2 is one of those aircraft.
The Antonov AN-2 is a single, radial piston engine transport aircraft, and is one of the biggest production single-engine bi-planes ever built. It was designed by Antonov in 1947 to meet the requirements of the Soviet Forestry Ministry to be used in agriculture and utility roles. The AN-2’s first flight was in August 1947.
It may seem strange that I would pick this aircraft to write about, but it has some interesting qualities and definitely has an impressive service record. The Soviet’s built over 5,000 of these aircraft by the 1960’s and licensed the manufacture of AN-2’s to Poland and China. Overall more than 18,000 AN-2’s had been built by the time that production was halted in 2001. That is more than double the number of Boeing 737’s that have been constructed!
Why was this aircraft so prolific? I believe the answer lies in the Soviet methodology of utilitarian simplicity. The designers purposely kept complex systems to a minimum and built an incredibly strong airframe primarily intended for off-airport use. Some examples of the ingenuity found in this airplane are quite interesting!
Setting the AN-2 apart
The Antonov AN-2 was built with an internal fuel pump for refueling, this allows the tanks to be filled straight from fuel drums. The brakes are pneumatic, and the aircraft carries an onboard compressor, (similar to the setup of a heavy truck). The shocks and tires are also adjustable by using this pneumatic system, meaning changes or adjustments can be made in the field by the pilot without special tools. The batteries are designed to be easily removed for service or replacement and are powerful enough that a GPU is not required to start the engine. The wings have leading edge slats that are completely automatic. They are held closed by airflow over the wings, however, at airspeeds below 40 MPH, they extend because of elastic rubber springs built into the slats. One of the most interesting things about the AN-2 is its slow flight and stall characteristics. The pilot operating handbook for the AN-2 has the following quote, “If the engine quits in instrument conditions or at night, the pilot should pull the control column full aft and keep the wings level. The leading-edge slats will snap out at about 64 km/h (40 mph) and when the airplane slows to a forward speed of about 40 km/h (25 mph), the airplane will sink at about a parachute descent rate until the aircraft hit the ground.” As such, pilots of the AN-2 have stated that they are capable of flying the aircraft in full control at 48 km/h (30 mph).” Multiple AN-2 pilots are also capable of controlled flight backward. In a roughly 35 MPH headwind, a pilot can maintain control of the aircraft while moving backward at 5 MPH!
In addition to these interesting qualities, the AN-2 is also quite the STOL heavy hauler. It can clear a 50’ obstacle and land on a grass strip in 1,417 feet. To clear a 50’ obstacle on take-off, it only needs 1,624 feet. The useful load on the AN-2 is 4,500 pounds, and with full fuel tanks, it can still carry 2600 pounds. It is not fast by any definition, the economy cruise is 100 KTAS, and the range is limited to around 500 NM. This is mostly due to the thirst of the 9-cylinder, 1000 HP radial engine.
Because of these impressive specifications, this aircraft was heavily used by the Soviet and eastern bloc militaries, and by dozens of countries throughout the world. Aeroflot operated the AN-2 as an airliner, and to this day it can still be found in some far-reaching regions moving passengers. Private operators in Africa, Southeast Asia, and Central and South America still use this aircraft for passenger, cargo, and missions’ operations. Recently the AN-2 has attracted the attention of pilots in the US and Canada who operate them as bush planes. Some AN-2’s imported to North America are required to be operated on an experimental certificate, however interestingly, due to a bilateral agreement with Poland, AN-2 aircraft built by PZL can be operated as a certified aircraft in the US. It is estimated that there are almost 2,000 AN-2 aircraft still in operation today.
The Future of the AN-2
The AN-2 has been out of production for 17 years, but its story is not over. Antonov is currently working on the AN-2-100, which is powered by a 1500 horsepower Motor-Sich MS-14 turboprop. This aircraft has already broken some class records during testing relating to weight and climb performance. It will be available as a conversion to existing airframes.
The Siberian Research Institute of Aviation (SIBNIA) has built a fully custom carbon fiber AN-2 with a Honeywell TPE 331-12UHR turboprop engine driving a 5 blade Hartzell propeller. This aircraft had its first flight on July 10th of 2017. Because of the new wing, the fuel capacity is greatly increased, and the top speed should be approximately 50% higher than the original.
Designed in 1947 and built for 54 years, the Antonov AN-2 has provided outstanding service to the pilot’s that relied on it for the last 71 years. Although this aircraft was completely outdated the day it was designed due to its biplane configuration. The AN-2 found its niche and excelled. Now, 2 different companies will be modifying this airframe so that it may serve many more decades into the future! It is possible that the AN-2’s best days are yet to come.