Polikarpov U-2 / Po-2 — Primary-Source Soviet Technical Documentation

The Polikarpov U-2 — redesignated Po-2 in 1944 in honour of its designer Nikolai Polikarpov — remains one of history's most-produced aircraft, with over 33,000 built between 1928 and 1953. Its extreme structural simplicity, forgiving flight behaviour, and near-indestructible wooden airframe made it the backbone of Soviet pilot training and, in wartime, one of the most effective low-level night harassment bombers of World War II.

This collection brings together original Soviet factory and military publications spanning 1937–1951, covering the U-2, U-2VS, U-2S, and Po-2 variants across their full operational life.

Document Manifest — 7 Original Soviet Publications

1. Самолет У-2 — Aircraft U-2
   Author: N. M. Lebedev — Issued by: Voenizdat (Military Publishing House), Moscow — 1937
2. Самолет У-2 — Aircraft U-2
   Issued by: Voenizdat — 1939
3. Самолет У-2 — Aircraft U-2
   Issued by: Voenizdat — 1941
4. Описание и Инструкция по эксплуатации электрического оборудования самолета У-2 и его модификаций
   Description and Operating Instruction for the Electrical Equipment of the U-2 Aircraft and Its Modifications
   Compiled by: Engineer NII GVF E. M. Gurov — Issued by: Editorial-Publishing Department of Aeroflot, Moscow — 1943
5. Указание № 534 Главного Инженера ВВС ВС СССР о введении в действие технического описания самолета По-2ВС
   Directive No. 534 of the Chief Engineer of the VVS Armed Forces of the USSR — Introduction of the Technical Description of the Po-2VS Aircraft into Service
   Signed by: Deputy Chief Engineer VVS, Lieutenant-General of Engineering Service Ageev — 6 August 1946 — Управление Военных Воздушных Сил ВС СССР
6. Самолет По-2 — Aircraft Po-2
   Authors: V. A. Ivanov, M. V. Lipatov — Issued by: Editorial-Publishing Department of Aeroflot (GVF), Moscow — Copy No. 2232 — For Official Use Only — 1946
7. Самолет По-2 и его Модификации — Aircraft Po-2 and Its Modifications
   Author: M. V. Lipatov — Issued by: Redizdат Aeroflota, Moscow — Copy No. 2136 — 1951

Performance Data

Aerodynamic Configuration

• High-Lift Biplane Design: Staggered biplane wings provide a very large effective chord and massive surface area (33.2 m²), generating high lift coefficients at very low velocities.
• Gliding Efficiency: Low wing loading (41 kg/m²) allowed the aircraft to serve as an efficient glider. During night-bombing operations — the legendary "Night Witches" — pilots routinely throttled back or shut off the engine entirely, using silent glides to approach targets undetected.
• Natural Speed Limiting: The all-wood, fabric-covered airframe generates high aerodynamic friction, naturally limiting terminal dive velocity to 150–160 km/h and preventing accidental high-G structural overstress.

Engine Technical Notes — Shvetsov M-11

• Layout: 5-cylinder, single-row, air-cooled radial — the first mass-produced entirely domestic Soviet aero engine.
• Displacement: 8.6 litres (525 cu in).
• Power Output: 100 hp (75 kW) baseline (M-11), scaling to 115–125 hp on later M-11D variants.
• Dry Weight: 165 kg (364 lbs).
• Mechanical Quirks: Exposed valvetrain with external pushrods and springs. Notorious for spraying oil over the forward fuselage. No electric starter — required manual hand-propping or compressed air bottle ground starts.

Handling & Stability

• Stall Resistance: Highly stable and physically resistant to spinning. If controls are released during a stall, the nose naturally drops to self-correct and recover airspeed.
• Control Surfaces: Massive, hyper-effective rudder yielding exceptional yaw authority at low speed. Ailerons somewhat heavy and sluggish, requiring coordinated rudder inputs for responsive turns.
• Crosswind Vulnerability: Low weight, large wing area, and slow flight speeds make the Po-2 highly susceptible to wind shear and strong crosswinds during takeoff and landing.

Engineering Bulletins & Field Modifications

• U-2VS / LNB Night Bomber: Underwing bomb racks (up to 350 kg / 771 lbs ordnance), visual mechanical bombsights, and a defensive 7.62mm ShKAS machine gun in the rear observer cockpit.
• Exhaust Flame Dampeners: Long exhaust pipes running along the fuselage side to diffuse engine flames, preserving pilot night vision and keeping the aircraft invisible to ground spotters.
• Landing Gear Interchanges: Field conversions replacing standard wheels with wide-footprint wooden skis for deep winter snow operations, or low-pressure float gear for marshland and river utility roles.

This 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.

⚠️ Regulatory Notice: Under FAA 14 CFR § 43.13 and EASA Part-M, any mechanic performing maintenance on an active aircraft must use current, manufacturer-approved revision-controlled data. This archival document does not satisfy that requirement.

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