The 'Sparka' Fishbed
One of my favourite aircraft types has to be the MiG-21 and in particular the twoseatversions of this 'krasiwij' aircraft that has been gracing the skies for more than 40 years now.
Production of the different variants.
Production started with the basic MiG-21U (Izdelye 66) which was powered by a R11F-300 engine. This machine was produced in two versions, the latest one having a broad chord fin with the dragchute-housing incorporated in the lower part. A few hybrid versions (small tail with dragchute-housing) were also build. A total of 180 for the Soviet Airforce were produced at the factory in Tbilisi between 1962 and 1966 while the ones designated for export were created at the GAZ 30 Znamya Truda factory in Moscow between 1964 and 1968.
Around 1966 the first productionversion of the MiG-21US (Izdelye 68) came to light. This aircraft was fitted out with another version of the R11F-300 engine with slightly improved performance when compared to the version in the MiG-21U. A total of 347 were build in Tbilisi, Georgia. They differ from the late MiG-21U in having a periscope mounted on top of the aft cockpit.
The ultimate twoseatervariant of the MiG-21 was launched in 1971. Before the end of production was reached in 1986 a total of 1133 UMs (or more?) had left the factory in Georgia. The MiG-21UM Izdelye 69 has the same engine as the MiG-21US (although some have the R13-300) and differs from this type almost exclusively on the inside. The UM has an angle-of-attack indicator on the lefthandside of the nose and most carry the VHF antenna on top of the spine. Probably all the operators of MiG-21 singleseaters around the globe also flew one or more twoseater variants.
Visual references for positive identification of MiG-21 twoseat-variants
MiG-21 twoseater serialnumbers
To try and solve The Great Puzzle of Eastern European Aircraft and in particular the MiG-21, one needs to comprehend the serialsystem used by the manufacturer. In doing so, coupled to a few readily available examples, one should be able to determine the approximate year and/or month of manufacturing or delivery. There are four systems used to identify the MiG-21 twoseaters and these are explained below.
System 1: export MiG-21U-400 and MiG-21U-600 (Type 66)
Utilizing a very simple system of batchnumber and number in batch the serialnumber is not too difficult to cope with. On paper the number is preceded by 66. For example one of the MiG-21s in storage at Craiova airbase in Romania bears number 2216. This would mean aircraft 16 from batch 22. The full 'paper' serialnumber would therefore be 662216. The MiG-21U built in the Znamya Truda factory only uses number-in-batch from 16 through 20. The switch from U-400 to U-600 was made around batch 23.
System 2: MiG-21U, MiG-21US and early MiG-21UM (Type 66, 68 and 69)
At first glance the serialnumber of the U, US and early UMs looks pretty complicated but looks can be deceiving! The factory at Tbilisi choose a system which is easy to comprehend. If not already apparent the third and fourth digit can be used to determine the exact type: 66 for the U, 68 for the US and 69 for the UM. The first two digits reveal the number of the aircraft in the batch. The batchnumber can be found at the end of the number; the last two digits. The remaining two digits are always 51 which is the factorycode. To give you an example: aircraft 01665101 is the 1st MiG-21U from the first batch, aircraft 02665101 is the second MiG-21U from the first batch etc etc. Production changed to MiG-21US at batch 19. The first UMs using this system are from batch 53 and the factory continued to identify MiG-21UMs in this way till at least batch 75.
System 3: MiG-21UM (Type 69)
The first four digits of the third serialnumbersystem look familiar. These are 5169 and have the same meaning as the 3rd through 6th number in the second system. These four are followed by the batchnumber given as a code. Only odd numbers are used to make things a little more difficult for us. The two-digit batchnumber is followed by a zero which has no function other than making things look very complicated! The last two digits are a code for the position of the aircraft in the batch. They use numbers 01, 06, 11, 16, 21 etc so add up five for every aircraft in line. To give an example aircraft 516903041 was build on 18 June 1973 and delivered to Hungary. Filtering out the unwanted figures we see 03 and 41 as the remaining numbers. This means MiG-21UM number nine from batchnumber two. The batch should run from 516903001 through 516903096 so 20 aircraft per batch. This system is used from around May 1973 until late 1978, the first aircraft obviously being 516901001 and the last one 516999096.
System 4: MiG-21UM (Type 69)
After the possibilities of system three had been used up after aircraft 516999096 something new had to be figured out. It was decided to continue the looks of system 3. However, did they start the 99-serie with 516999001 and used the 3rd system (so the second aircraft would be 516999006) or did they start using 516999001, 516999002 etc etc?. Only the last three digits seem to be important in this system. The 0 and 5 were not used as last digit on aircraft manufactured before the second half of 1981. The last aircraft I could find was 516999507 which was build on 20 March 1986 (almost twentyfive years after the first MiG-21 'Sparka' left the factory!) and delivered to Hungary as 507.
Any additions and/or corrections as well as additional serialnumbers are warmly welcomed at the e-mail address below.
© Robin Polderman 2002 / updated 2 April 2002