Bolkhovitinov DB-A

The Bolkhovitinov DBA (Dahl'niy Bombardirovshchik-Akademiya – long-range bomber, academy) was a heavy bomber aircraft designed and built in the USSR from.

Development
Bolkhovitinov became the head of the VVIA design group at the VVA Zhukovskii ( - VVS academy Zhukovskii ) tasked with the design of a replacement for the Tupolev TB-3 heavy bomber. The resulting DB-a was advanced for its day with stressed skin aluminium alloy construction throughout with clean lines, neatly cowled engines and trousered main undercarriage legs, with fully retracting main-wheels and tail-wheel. The split flaps, undercarriage, nose turret and bomb-bay doors were all operated by a pneumatic system re-charged by engine driven compressors. Flight trials began on 2 May 1935 at Khodinka pilotted by N.G. Kastanyev and Ya.N. Moseyev, factory tests were completed by April and NII testing was carried out inMay and June 1935. The excellent performance demonstrated included, sustained flight at an altitude of 2,500m (8,202 ft) with two engines shut down, and 4,500 km range.

A decision was made to fly non-stop from Moscow to the USA and the DB-A was modified to fly, at an overload weight of 34,700 kg (76,500 lb), carry enough fuel to fly 8,440 km (5,244 miles). The red painted DB-A prototype under command of Sigizmund Levanevsky departed Moscow Shchyelkovo airport on the 12th of August on an attempt to fly to Fairbanks, Alaska. After 14hrs 32min the crew sent a radio message that one engine had failed and gave a revised ETA for Fairbanks, but nothing further was heard from the DB-A and the fate of the aircraft and crew remains a mystery.

A second aircraft with increased gross weight, improved airframe, re-designed nose and more power was completed and flown in March as the DB-2A. An order for 16 aircraft was placed late in 1937, with the designation DBA, but only twelve were completed due to the advent of the TB-7 / Pe-8.

Variants

 * DB-A – The initial prototype aircraft, with M-34RN engines, lost on a non stop flight Moscow to Fairbanks, Alaska.
 * DB-2A – The second prototype with many detail improvements and M-34RNV engines.
 * DBA – Production aircraft ordered in 1937. Sixteen aircraft ordered, but only twelve completed, with M-34FRN engines plus turbo-chargers, rearwards retracting main undercarriage, gunners cockpits in the rear of the inner engine nacelles, and other modificatoions.
 * TK-1 TK ( - heavy cruiser) – Projected escort bomber with 11 crew, 3xShVAK + 3,000 rounds, 5xShKAS + 11,000 rounds and underwing rockets.