<<(...) YAK-40 MODIFICATIONS & PROJECTED VARIANTS
With so many Yak-40s built and the type proving successful, it's not surprising that upgrade efforts were performed to keep it in service. The upgrades featured airframe refurbishment, update of avionics for international service, and very often conversion to VIP configurations. Even Yak-40Ks have been updated to VIP configurations, it appears with the cargo door sealed shut. There have also been a few "long-range" updates, designated "Yak-40D/40KD", where "D" stands for "dalniy (range)", involving addition of more fuel tanks in the wings for an effective doubling of range.There were several special-mission conversions of Yak-40s: Navigation aids calibration aircraft, externally similar to a "stock" Yak-40 except for a few added antennas, with such machines used by several Eastern European nations. A number of one-off weather research platforms with names like "Akva (Aqua)", "Liros", "Shtorm", and "Meteo" -- the last being a fairly common name for a Soviet weather research aircraft. Details are not all that clear, though a photo of the Yak-40 Meteo shows a heavily modified machine with a ventral equipment pod, observation windows, and a nose probe. Four conversions by the Polish Air Force as tow-target tugs, with the winch and other gear installed in the rear door; the forward service door had to be used by the aircrew to get in and out.Several engine and avionics testbeds, for example one aircraft flown by the Lavochkin OKB for test of air and space vehicle subsystems. A single prototype of a "Yak-40DTS" military transport with paradrop and medical evacuation ("medevac") capabilities was built, it seems as a modification of a stock Yak-40. It did not go into production.There were many concepts for revised Yak-40s that were not built. The Soviets were very enthusiastic about vertical takeoff / landing (VTOL) aircraft in the 1960s, with a particular fascination for "liftjets" -- small turbojets that could be mounted near-vertically in an aircraft to provide high VTOL thrust for a short period of time. The Yak OKB came up with a design for a VTOL Yak-40 with four Kolesov RD36 liftjets in the forward fuselage and four such liftjets in the rear fuselage. An alternate, on the face of it more practical, arrangement featured four RD36 liftjets in a pod in each wing. The VTOL Yak-40 concepts were never more than "paper projects".>> {fonte : http://www.airvectors.net/avyak40.html; (...) omissis} / (... foto) /
<<Another concept that survives as a desktop model envisioned four small engines of unknown make, two on each side of the tail, along the lines of the US Lockheed Jetstar executive jet. Apparently there was a "stretched" machine along the same lines, with four larger engines; capacity for up to 44 passengers; and twin-wheel main gear to support greater weights.In the early 1990s, the Yak organization floated schemes for restarting production of the Yak-40, updated twin modern small high-bypass turbofans, one arrangement featuring the Textron Lycoming L507-1N, providing better performance and range. The updated Yak-40 would have modernized avionics as well, with some design concepts featuring a slightly swept wing to increase efficient cruise speed. It was an appealing idea, but it simply didn't happen.>>{fonte : http://www.airvectors.net/avyak40.html; (...) omissis}
Yak 40, testing VTOL in ambiente FSx
15/09/2015
