False keel
False keel comes from the field of shipbuilding and originally referred to an additional keel that was attached below the real keel of wooden ships. The term was still used in connection with iron ships in 1874, but after that the use in the nautical sector can no longer be proven. In modern ships, the function of the component is taken over by ship stabilizers.
The term found its way into the Russian language as early as the 18th century and is used e.g. B. mentioned in a book on historical Russian grammar from 1866.
More recently, false keel has been used in Russian publications to denote the enlargement of the rudder surface by rounding the fin roots or for additional stabilizing fins under the fuselage of aircraft. Based on this, the term also appears in German-speaking countries in connection with Russian aircraft. The false keel not only serves to improve directional stability at high speeds, but above all to improve the flow behavior around the rudder unit at high angles of attack. On subsonic aircraft such as the Zlín Z-42 , Il-12 or Tu-14, the false keel is located in front of the vertical stabilizer, on the faster military aircraft the MiG-17 , MiG-21 , Jak-28 , MiG Je-8 , Xian JH-7 or Chengdu J-20 , the stabilizing fins are attached to the rear of the fuselage. Since false keels increase the risk of a tail strike, a tailbumper was also attached to the MiG-17 .
See also
Individual evidence
- ^ Definition in: A Study of English Nautical Loanwords in the Russian Language of the Eighteenth Century : Google Snippet
- ↑ Communications from the areas of the sea, Volume 2: Google Snippet
- ^ Russian Historical Grammar , 1866: Google Snippet
- ↑ Military History Museum of the Bundeswehr - Air Force Museum Gatow , description of the MiG-21