{"product_id":"polikarpov-i-15-technical-descriptions-books-1-2","title":"Polikarpov I-15 — Technical Descriptions, Books 1 \u0026 2","description":"\u003ch2\u003ePolikarpov I-15 \"Chaika\" (Gull) — Soviet Biplane Fighter\u003c\/h2\u003e\u003cp\u003eThe Polikarpov I-15 \u003cem\u003eChaika\u003c\/em\u003e (Gull) was a legendary interwar Soviet biplane fighter designed by Nikolai Polikarpov. It featured a distinct \"gulled\" upper wing layout that optimized both aerodynamic drag reduction and forward visibility.\u003c\/p\u003e\u003ch3\u003eAerodynamic Reports\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWing Profile:\u003c\/strong\u003e The design utilized a high-lift Göttingen 436 airfoil section across both its upper and lower mainplanes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGull Wing Geometry:\u003c\/strong\u003e The original I-15 featured an upper wing that angled directly into the fuselage, eliminating structural interference drag at the wing-to-body joint and drastically enhancing upward visibility for the pilot.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConventional Configuration (I-15bis):\u003c\/strong\u003e To improve directional stability during weapon aiming, the subsequent I-15bis variation reverted to a traditional continuous upper wing supported by N-struts. This shift decreased its maximum roll rate.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCowling Upgrades:\u003c\/strong\u003e Early variants had open or minimal Townend rings. Later models used a fully enclosed NACA cowling to clean up boundary-layer separation over the engine cylinders, reducing aerodynamic drag.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eEngine Technical Notes\u003c\/h3\u003e\u003cp\u003eThe fighter evolved through three distinct air-cooled powerplant installations:\u003c\/p\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eEngine Model\u003c\/th\u003e\n\u003cth\u003eOrigin\u003c\/th\u003e\n\u003cth\u003eType\u003c\/th\u003e\n\u003cth\u003ePower Output\u003c\/th\u003e\n\u003cth\u003eTechnical Characteristics\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eShvetsov M-22\u003c\/td\u003e\n\u003ctd\u003eLicensed Bristol Jupiter\u003c\/td\u003e\n\u003ctd\u003eSingle-row radial\u003c\/td\u003e\n\u003ctd\u003e480 hp\u003c\/td\u003e\n\u003ctd\u003eUsed on initial 404 airframes due to production delays of the M-25.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShvetsov M-25\u003c\/td\u003e\n\u003ctd\u003eLicensed Wright R-1820 Cyclone\u003c\/td\u003e\n\u003ctd\u003eNine-cylinder radial\u003c\/td\u003e\n\u003ctd\u003e700–715 hp\u003c\/td\u003e\n\u003ctd\u003eTwo-bladed variable-pitch propeller, optimizing high-altitude performance.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShvetsov M-25V\u003c\/td\u003e\n\u003ctd\u003eSoviet-uprated M-25\u003c\/td\u003e\n\u003ctd\u003eForced-induction radial\u003c\/td\u003e\n\u003ctd\u003e750–775 hp\u003c\/td\u003e\n\u003ctd\u003eHigh-altitude version designed to maintain optimal manifold pressure.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eHandling \u0026amp; Stability Studies\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRoll Rate:\u003c\/strong\u003e The original I-15 delivered an exceptional roll rate of over 240 degrees per second, allowing standard aileron rolls in under 1.5 seconds.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTurn Dynamics:\u003c\/strong\u003e The aircraft maintained a remarkably tight turning circle, completing a full 360-degree flat turn in just 8 to 9 seconds.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeapon Aiming Tradeoff:\u003c\/strong\u003e Flight test logs revealed that weapon-trigger cable tension, combined with overly light and sensitive control surfaces, made precise targeting difficult for novice pilots.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight Penalties (I-15bis):\u003c\/strong\u003e The structural redesign added weight, increasing the 360-degree turn duration by 2 to 3 seconds and restricting transition agility between maneuvers.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003ePerformance Data — Shvetsov M-25 Production Variants\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMaximum Speed: 367 km\/h (228 mph) at 3,000 m\u003c\/li\u003e\n\u003cli\u003eCruising Speed: 285 km\/h (177 mph) at 2,000 m\u003c\/li\u003e\n\u003cli\u003eService Ceiling: 9,800 m (32,200 ft)\u003c\/li\u003e\n\u003cli\u003eRate of Climb: 1.1 min to 1,000 m; 6.1 min to 5,000 m\u003c\/li\u003e\n\u003cli\u003eOperational Range: 510 km (320 miles)\u003c\/li\u003e\n\u003cli\u003eEmpty Weight: 1,012 kg\u003c\/li\u003e\n\u003cli\u003eGross Takeoff Weight: 1,385 kg\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eEngineering Bulletins\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eArmament Upgrades:\u003c\/strong\u003e Early batches mounted two synchronized 7.62 mm PV-1 machine guns. Production lines later transitioned to a four-gun layout via an upper fuselage battery paired with an integrated 9 mm armored pilot seat.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeapon Wing Orientation:\u003c\/strong\u003e Bulletins resolved early barrel jam and clearing failures caused by mounting internal wing guns upside down to fit the tight bays.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAuxiliary Fuel Modifications:\u003c\/strong\u003e Service updates introduced supplementary external under-wing drop tank points (50-liter capacity units) to boost the aircraft's short operating range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSuspension \u0026amp; Landing Gear:\u003c\/strong\u003e Engineering revisions added heavy-duty cantilever mainwheel legs and shock absorbers to prevent nose-over landing tendencies on rough, unprepared front-line airfields.\u003c\/li\u003e\n\u003c\/ul\u003e\u003chr\u003e\u003cp\u003e\u003cem\u003eThis is an archival, static-copy edition fixed at its original publication date. Intended for historical reference, flight simulation, museum restoration, and educational use only. Not approved for active airworthiness maintenance under FAA 14 CFR § 43.13, EASA Part-M, or equivalent international regulations. Operators of active aircraft must use current, revision-controlled publications from the Type Certificate holder or an authorized distributor.\u003c\/em\u003e\u003c\/p\u003e\u003cp\u003eLiving Collections with Free Lifetime Updates — Please review our Disclaimer and Export Notice before purchasing.\u003c\/p\u003e","brand":"Online Aviation Library","offers":[{"title":"Default Title","offer_id":53510457983323,"sku":null,"price":20.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0955\/4788\/3867\/files\/polikarpov-i-15bis-overhead-banner.png?v=1783187414","url":"https:\/\/onlineaviationlibrary.com\/products\/polikarpov-i-15-technical-descriptions-books-1-2","provider":"Online Aviation Library","version":"1.0","type":"link"}