Like the global powers of the West during the Cold War decades, the Soviet Union moved on rapid testing and development of many jet-powered aircraft. After World War 2 - a war which witnessed the apex of prop-powered fighters - the turbojet engine became firmly entrenched as the next propulsion system of choice for military fighters and bombers and engineers on all sides raced against the clock in an attempt to mate the still-infant technology with a perfected high speed frame. Yakovlev OKB, founded prior to the war in 1934, was one of the power players in the Soviet defense industry during this period, joining stalwarts Mikoyan-Gurevich, Lavochkin, and Sukhoi in the race against the West.
In 1947, Soviet engineers at Yakovlev OKB revealed their Yak-25 interceptor prototype - a straight-winged aircraft with single vertical tail fin, high-mounted horizontal tailplanes, and a forward-set cockpit. The aircraft was intended to compete with designs being offered to the Soviet Air Force from Mikoyan-Gurevich and Lavochkin. The single turbojet engine was aspirated through the nose and was nothing more than a Rolls-Royce "Derwent" V centrifugal compressor-based system of 3,500lbf thrust output. First flight of this aircraft was on November 2nd, 1947 with testing lasted until July of the following year.
While performance of the Yakolev offering proved excellent for the period, it lacked high speed stability due to its use of a straight wing mainplane arrangement - severe buffeting being the result. A new tail unit failed to alleviate the issue and the competing design by Mikoyan-Gurevich - to become the famous MiG-15 - was selected ahead of all others. While this ultimately led to a stoppage on the Yak-25 product per se, work continued on what would become the "Yak-30" .
To compete with the swept-back wing submissions from Mikoyan-Gurevich and Lavochkin (the La-15) an endeavor arose that attempted to see the Yak-25 fitted with swept-back wings herself. The resulting aircraft featured the same general design layout of the Yak-25 but its wing mainplanes now featured 35-degree sweepback. Boundary layer fences were prominent along the dorsal face and, underwing, external fuel tanks were carried (early turbojets were thirsty systems limiting operational ranges). The aircraft carried over the same tubular fuselage of the Yak-25 as well as the open nose section that was used to aspirate the Derwent turbojet within (the copy of the British engine was the "RD-500" and manufactured (illegally) by Klimov OKB). The pilot sat in a cockpit at front with generally good views out of the provided canopy that featured framing only along its forward panels. The tricycle undercarriage was wholly retractable. The engine exhausted through a circular jetpipe under the tail with the tail unit itself made up of a single vertical fin with mid-mounted horizontal planes. In several ways, the Yak-30 mimicked many of the design lines adopted by both the Mikoyan-Gurevich (in their classic MiG-15 fighter) and Lavochkin (in their La-15).
NOTE: The "Yak-30"designation, while used in this ultimately abandoned Soviet jet program, was resurrected down the road in 1960 for yet another Yakovlev product - this being the Yak-30 "Magnum" jet-powered trainer of which four were constructed. The two products have no direct link between them.
The Klimov RD-500 turbojet engine developed upwards of 3,505lbf thrust output which provided a maximum speed of 636 miles per hour, a range out to 1,068 miles, a service ceiling of 49,215 feet, and a rate-of-climb of 8,070 feet per minute. In comparison, the MiG-15 (MiG-15bis mark) received 6,000lbf thrust output from its Klimov VK-1 turbojet and reached speeds of 658 miles per hour, a range out to 770 miles, operated at a service ceiling of 50,855 feet, and sported a rate-of-climb of 10,080 feet per minute.
Proposed armament for the Yak-30 was to be 3 x 23mm Nudelman-Rikhter NR-23 autocannons with 75 rounds to a gun.
Two Yak-30 prototypes were realized from the now-stillborn Yak-25 program. First flight of the initial model was recorded on September 4th, 1948 though it was the second prototype that incorporated far more beneficial changes such as Fowler-type flaps (replacing the original split arrangement), air brakes, and revised landing gear door panels. Onboard systems were also improved as was internal volume. The Yak-30 proved faster and only slightly heavier than its forerunner but, unfortunately for Yakovlev engineers, the sweptback mainplanes persisted in being problematic at the speeds required.
Due to the official adoption of the MiG-15 into the Soviet Air Force inventory, the Yak-30 was not under any real consideration to find similar favor by the service. It was left to essentially live out its days as a data collection / research platform exploring various aeronautical fields including that of sweptback wings and turbojet propulsion. The program was eventually terminated in its own time after the usefulness of the product had been met. Only the two prototype Yak-30 aircraft were ever completed. In comparison, over 18,000 MiG-15s were produced and 235 of the Lavochkin La-15 were also taken on. Both were introduced in 1949.