by James B. Haycraft

Did the Soviet Polikarpov I-153 biplane fighter see action in Spain in the waning months of the civil war, joining over 250 other different types of aircraft that served in that bloodiest of conflicts? Although hardly of major historical import, the question has nevertheless been raised and debated by aviation researchers and historians on more than one occasion since the end of the war in 1939. Based primarily on the publication of illustrations depicting this aircraft in supposedly authentic Republican markings, along with mention of its use in Spain in various articles and books, the supposition's validity has been in doubt due to a lack of suitable photo and text documentation.

With the publication of Volume 1 of Justo Miranda's and Paula Mercado's exemplary work on Spanish civil war aircraft, AVIACION MUNDIAL EN ESPANA 1936-1939, the question has been raised once again. (1) Published in 1985 and subtitled "Aviones Americanos y Rusos," this first volume of a planned 7 volume series, devotes 6 pages to the I-153 "Chaika," with 3 pages of drawings in 1/72 scale, showing various details of the aircraft, plus a 3-view tone drawing illustrating the craft in a Republican color scheme.

Inspired by an illustration attributed to a Keith Ward, supposedly published in the bulletin of the AAHS, which was, in turn, based on information supplied by another AAHS member, Clark Macomber, the authors believe that Ward would have required at least two photographs to supply sufficient detail on which to base the illustration and its color scheme. (2) Without doubting the existence of such photos, they nevertheless feel the scheme is an unlikely one and the code number on the rudder inappropriate for a Republican aircraft in 1938. (3) Despite their reservations, the husband and wife team of Miranda and Mercado believes that it was possible for the I-153 (or its pre-production prototypes) to have been in Spain during the final months of 1938, briefly engaging in combat before returning to the Soviet Union.

The question of the I-153's role in the civil war may have first arisen in 1961 when William Green, the well-known British aviation historian, affirmed its presence in Spanish skies in Volume 3 of his series, WAR PLANES OF THE SECOND WORLD WAR, although later published articles on Polikarpov fighters (in 1971 and 1980) by the same author omitted any such statement. Whether this was a deliberate omission based on the author's subsequent inability to find suitable documentary evidence or a simple oversight, it did little to lay the matter to rest and speculation has continued regarding the use of this third variation of the I-15 "Chato," which had been in Spain since October of 1936, when Russian personnel and equipment, including the more modern I-16, began to arrive in sizeable quantities. The Spanish aviation historian, Salvador Rello, also claimed that the I-153 was in Spain in the final months of the war, with the total number not exceeding 10 aircraft. (4) More recently, French author Herbert Leonard, in his little volume on Polikarpov fighters, mentions a "handful" of I-153s, when summing up the total of Polikarpov fighters sent to Spain during those fateful years. (5)

Over 380 I-15 "Chatos" were used by the FARE (Fuerza Aerea de la Republica Española) during the civil war, comprising the major part of the republic's fighter force. The initial evaluation of its combat performance revealed, that despite a creditable performance against Nationalist fighter aircraft, such as the Italian Fiat CR32 and the German Heinkel He51, it still lacked sufficient speed and altitude performance to do much more than cope with such competition. Athough possessing excellent maneuverability, the I-15 frequently came off second best, especially when pitted against the new Messerschmitt Bf109 that began to arrive in Spain in the spring of 1937. Its mediocre combat performance against the new German monoplane was viewed with dismay in the Soviet Union, where performance appraisals and critiques were carried out on a continuing basis as action reports from Soviet fighter commanders in Spain were received and evaluated. (6)

Although a trend toward more modern monoplane fighter aircraft was certainly well established within the Soviet Union, as evidenced by the development and production of the I-16, many traditionalists still favored the superior maneuverability of the biplane and pushed for improved versions of the gull-winged I-15 almost as soon as it began to enter squadron service with the Soviet air force in 1934. (7) Polikarpov and his associates aggressively took up the challenge and the resulting I-152 (or I-15bis) corrected some of the original's more obvious deficiencies. The poor pilot visibiity occasioned by the gull-wing configuration was somewhat improved by a more conventional cabane strut mounted upper wing with a new, more efficient airfoil section. The powerful 750 hp. Shvetsov M-25V radial engine, with an aerodynamically improved cowling, replaced the I-15's 635 hp. M-25, a license-built version of the American Wright Cyclone. A fixed landing gear capable of mounting skis or spats and some minor structural changes essentially completed this modification. However, when all was said and done, only a modest improvement in performance was achieved, with maximum speed increased to 385 km/hr. at 3000 meters, from the I-15's 360 km/hr. at the same altitude. The maximum altitude remained at 9000 meters, essentially the same for both aircraft.

The I-152's first combat operations were flown against the Japanese over Nanking in the latter part of 1937; approximately 200 aircraft having been supplied to the Nationalist Chinese government by the Soviet Union. An additional quantity was assigned to Spain, some 31 aircraft reaching Barcelona by sea late in 1938, with approximately 64 others intercepted while enroute via rail and interned in France until the end of the war when most were returned to the Soviet Union still in shipping crates. Some sources aver that 2 squadrons were in operation before the end of 1938, but it is more generally believed that 3 squadrons of these "Super Chatos" formally entered Republican service in January 1939, receiving the code "CC," which had originally been assigned to the early Soviet-built I-15s. Details of the brief combat career of the I-152 in Spain remain obscure, but it was most likely devoted to ground attack missions.

Soviet assessment of combat operations against the Japanese in China revealed that the I-152 was still lacking the performance necessary to successfully compete against modern monoplane fighter designs and the decision to pursue yet a third version was made early in 1938. It was quickly determined that a retractable undercarriage was necessary, along with a return to the gull wing configuration, although the advanced airfoil section selected for the I-152 was retained. The potent 1000 hp. M-62 radial replaced the I-152's 750 hp. M-25V and overall performance was notably improved. Top speed at 4600 meters was now 444 km/hr., with a maximum ceiling of 10,700 meters, along with an increased radius of action; performance features that now compared favoraby with contemporary monoplane fighters, such as the I-16 and Bf109. The new I-15ter or I-153, resembled the original I-15 to a remarkable degree and from a distance, with the landing gear down, it would have been quite easy to confuse the two.

In the autumn of 1938, the bloody Battle of the Ebro was reaching its critical phase and the fate of Republican Spain was now hanging in the balance. After active participation for almost two years, the Soviet Union had essentially written off its Spanish adventure as a lost cause and was then withdrawing its air force personnel, albeit leaving most of their aircraft behind. The violent air battles now raging over Catalonia were severely depleting Republican fighter and bomber strength. Although both sides had fought each other almost to a standstill, Nationalist air power, with full support of the Legion Condor, was still paramount and increasing. With the Russians disengaging their personnel from shrinking Republican territory, this would seem to have been an unlikely time to introduce a new aircraft for combat evaluation. Nevertheless, new wings were aloft in Spanish skies and their entry into combat was observed by fighter pilots of the Legion Condor's 3./J88 and their commander, Hauptmann Werner Mölders.

The 25 year-old Mölders had relieved Adolf Galland as commander of Jagdgruppe 88's third squadron (3./J88) in May and proved to be an inspired combat leader and a gifted tactical innovator. Initially flying the obsolescent Heinkel He51 on ground attack missions, he and his squadron were soon outfitted with the new Messerschmitt Bf109Cs and Ds in July 1938. (8) Flying from the Legion's big air base at La Cenia, Mölders and his men began to enjoy an increased measure of success flying the new fighter against the harried and frequently outnumbered Republican forces. By early October 1938, Mölders had achieved 11 aerial victories, all I-15s or I-16s, except for a sole SB-2, a fast twin-engined bomber invariably refered to as the "Martin" despite its purely Russian origin.

The last day of October 1938, was one of the most action filled for the German airmen, as they continued the struggle for air supremacy over the Ebro front. As Mölders noted in his carefully kept war diary....."the war was again blazing in full fury. Today, a new enemy aircraft plunged into the battle - quite speedy and with an excellent rate of cimb. They came up over 8000 meters after us, using the same tactics as we did, but not pressing their attack as aggressively as German pilots would if we had our enemies by the nose! Nevertheless, some of our pilots, after being attacked by such opponents, were lucky to return to base safely, with only a few hits." (9) Mölders and his men engaged these aggressive new fighters, along with I-16 "Ratas" from two additional squadrons that appeared on their flanks. In the swirling combat action that followed, Mölders quickly gained the upper hand over an opponent, who soon fell out of control and plunged to earth. This 12th. victory was quickly followed by a 13th. and, as Mölder relates....."the spell cast by this new adversary was thus broken!" (10) Aside from mentioning a good turn of speed and an excellent climb rate, Mölders' diary is remarkably non-specific, omitting technical details and other particulars that would have helped to identify this new fighter aircraft. The characteristic of the I-153 that would have been most obvious - the retractable landing gear - wasn't mentioned. Thus, we are still left in the dark as to the type of fighter plane Mölders and his squadron encountered on that fateful October day over the Ebro, when pilots of 2 and 3./J88 claimed victories over 8 I-16s and 2 I-15s.

In his unpublished manuscript, WERNER MOLDERS EN ESPAGNE (essentially a French translation of the Spanish Civil War chapters of von Forell's MOLDERS UND SEINE MANNER, with additional material apparently abstracted from Josef Fözö's memoir, FREIE JAGD VON MADRID BIS MOSKAU), the Canadian aviation researcher Michel Lavigne describes the air battles that day in some detail and identifies Mölders' 12th. and 13th. victories as I-153s in the victory list appended to the manuscript, apparently assuming the new "birds" described in Mölders' diary were indeed I-153s.

Perhaps the most authoritative published account of the Legion Condor, Ries and Ring's well-researched and profusely illustrated LEGION CONDOR 1936-1939, identifies Mölders' "kills" that day as I-16s in its comprehensive victory list. (11) However, mention is made of the fact that German pilots "again reported the appearance of a new "Curtiss" type, almost as fast as the Bf109s, with excellent rate of climb and carrying out their attack at a surprisingly high altitude." (12) To assign such performance chracteristics to the I-152 would appear to be stretching the facts, but its reported arrival in the Barcelona area during the latter part of 1938 may provide a clue as to what the new "Curtiss" type may have been. After all, to encounter a new aircraft, exhibiting admirable speed and altitude performance, apparently close enough in appearance to the familiar I-15 "Chato" to earn the appellation "Curtiss," without noting that it had retractabe landing gear as one of its distinguishing features, would seem to be an oversight of the worst kind on the part of experienced combat pilots. Unless, of course, the aircraft in question had no such distinguishing feature to comment upon!

What were the mysterious fighters that engaged the Legion Condor's Messerschmitts that day over the Ebro? Were they indeed I-153 prototypes hurriedly shipped to Spain to test the validity of the new redesign in combat, then hastily disassembled and returned to the Soviet Union? The Russians were certainly capable of such an operation and would have been keenly interested in seeing what the I-153 could do against their German opponents, testing the advantages, if any, of maneuverability versus speed in a combat environment. They had already tested most of their latest combat aircraft in Spain since their original intervention; why not take advantage of one more opportunity? Some prototypes (and even limited production quantities) could have been available as development of the 153 had begun early enough in 1938 to have permitted a few examples to be flight-ready by October. Transfer of these aircraft to still open Republican ports and their subsequent assembly would have been possible, even at that late date. The lack of photographic evidence is unfortunate but understandable. Within the shrinking enclave in Catalonia, with the fall of Barcelona imminent, taking photographs was probably not a priority task, and anyway, an I-153 (or I-152) sitting on the ground would have been just another "Chato" to the casual observer. (13)

Until some definitive photographic or documentary evidence surfaces to confirm the presence of the I-153 in Spain, it is doubtful if this final version of Polikarpov's biplane fighter flew in Spanish skies during the latter part of 1938, artistic representations notwithstanding. If published versions of combat diaries can be believed, the Legion Condor's Messerschmitts did indeed tangle with some unfamiliar fighter aircraft over the Ebro front during October and possibly November of 1938. The most likely candidate? The first I-152s, probably with Russian pilots in the cockpits, making their combat debut somewhat in advance of their "official" appearance in squadron strength in early 1939! The German pilot's favorable evaluation of the new aircraft's performance was, of necessity, a very subjective one. Made in the heat of combat, and perhaps compared to the performance of the well-used, hard flown Messerschmitts of J/88, this new "bird" did indeed appear to be a "hot" performer! (14)

The myth of the elusive I-153 "Chaika" will no doubt remain to fascinate the Spanish Civil War aviation enthusiast for years to come. At least, until some obscure archive in Spain or Germany produces the faded photograph or wrinkled document that finally sets the story straight.


1. Miranda, Justo and Paula Mercado. AVIACION MUNDIAL EN ESPANA (GUERRA CIVIL) 1936-1939: Aviones Americanos y Rusos. Silex Ediciones: Madrid 1985. An excellent reference source, especially for modellers of Spanish Civil War aircraft. Its extensive and detailed 1/72 scale drawings illustrate a multitide of unusual camouflage and markings schemes and the technical and historical information is of considerable value.
2. A reference to one of the two publications of the American Aviation Historical Society (AAHS), either its quarterly JOURNAL or the NEWSLETTER. Which of the two publications or which issue is not identified and the authors were apparently unable to locate additional or more up-to-date information. Another note of interest: a small profile drawing of an I-153, with the same number (8-3) appeared in the Vol. 2, No. 6, 1968 issue of the IPMS/France Journal, sporting a dark green/light blue fuselage color scheme.
3. The odd color scheme and number have been suggested as having a post-civil war origin as part of a Soviet-inspired propaganda ploy to play up their part in the war. Or perhaps the scheme is nothing more than someone's artistic license being given full reign.
4. As quoted in an article appearing in Issue 262 of the Spanish magazine FLAPS. Whether Rello or Leonard were reporting the results of their original research or merely repeating what had been published elsewhere is unknown; their sources of information are not identified.
5. Leonard, Herbert. LES AVIONS DE CHASSE POLIKARPOV. Ouest France: Rennes 1981.
6. Boyd, Alexander. THE SOVIET AIR FORCE SINCE 1918. Stein & Day: New York 1977. Chapter 5, entitled Stalin's Falcons, describes the Soviet contribution to the Spanish air war briefly, but authoritatively.
7. Ibid, Page 82.
8. Not all of the 109s received by 3./J88 were new; some old and frequently repaired B-1s were transfered from 2./J88 and flown for a brief time. Mölders wingman, Uffz. Franz Jaenisch, inherited the venerable 6-6 from the 9 victory ace, Herbert Ihlefeld, promptly wiping it out in a crash landing on 7/25/38. Mölders reportedly flew 6-7 for a short time before being assigned 6-79, a new D model.
9. von Forell, Fritz. WERNER MOLDERS; FLUG ZUR SONNE. Druffel Verlag: Leoni am Starnberger See 1976. This is basically an updated and expanded verson of the same author's 1941 work, MOLDERS UND SEINE MANNER, which was published just before Mölders death in November of that year. The extracts from Mölders' war diaries are essentially identical in both books.
10. Ibid, Page 71.
11. Ries, Karl and Hans Ring. LEGION CONDOR 1936-1939: Eine Illustrierte Dokumentation. Verlag Dieter Hoffmann: Mainz 1980. This large-format volume contains a wealth of superbly reproduced, previously unpublished photographs, both aircraft and personnel, coupled with an extensive, well-researched text and many fact-filled appendices. An indispensible reference source, despite some errors.
12. Ibid, Page 200.
13. A pristine I-153 in Soviet colors and markings is displayed in the Musee de l'Air at Le Bourget, near Paris. Captured in Russia by the Luftwaffe during WWII, this example has often been claimed, without factual basis, to be one interned in France after the capitulation of Republican Spain in 1939.
14. Salas Larrazabal, in AIR WAR OVER SPAIN (Ian Allen Ltd. 1974), the English language edition of his book, LA GUERRA DE ESPANA DESDE EL AIRE (Editions Ariel. Barcelona 1972), offer some confusing and indeed, startling information. In a list (in one of the many appendices) purporting to show aircraft types and quantities, both Nationalist and Republican, used until the end of 1938, the I-152 is not listed, although another list covering the period through March, 1939 shows 15 "I-15Bs." In a narrative statement accompanying these lists, he states that at least 34 "Super Chatos" numbered from CC-001 upwards were in Spain during the last quarter of 1937, operating on the Teruel front! This would be rather remarkable information, if true! Although it would appear that he meant the last quarter of 1938, this statement perpetuates the original error which appeared in the revised 1972 Spanish edition. He also notes the presence of the I-153 (quantity unknown) in the March, 1939 period, without further comment.

This article was first published in SMALL AIR FORCES OBSERVER, Vol. 11, No. 4 - October 1987 issue. This current article contains some minor changes and does not include the 3-view drawing (adapted from Justo Miranda's artwork) showing the purported color scheme of the Republican I-153.