The IL-28 benefitted from the German connection and post-war work. While it was not a direct copy or evolution of a Junkers design.
JU 287
The Ju 287 was the real deal. Hans Wocke had the initial task of developing a high-speed heavy bomber to elude Allied interceptors with sheer speed in 1943. Knowing the advantages of sweep on wings for speed, the down side was poor low speed characteristics. This is where forward sweep came in.
Put together from an He 177 fuselage and the tail of a Ju 388 plus some assorted scavenged parts the V1 took to the air in August 1944 with four 1,984 lb. thrust Jumo 004B-1s for power with three jettison-able 2,645 lb. thrust Walter 501 RATO (rocket pack to assist takeoff). Two of the engines attached to the rear lower wing and two at the "chin" alongside and forward on the fuselage.
Flight tests revealed that forward mount of the wing engines would be better and Ju 287 V2 was an all-new plane with no borrowed parts. Originally, four 2,866 lb. thrust He S 011s on the wings were to be used but there were delays in getting them in mid-1944 so six 1,760 lb. thrust BMW 003A-1s were used- four under the forward wing edge and two along the forward fuselage. Flight test details are lost to history but the outcome spurred the Air Ministry to order building of the V3 prototype and production to commence quickly. The V3 was to carry an 8,818-pound bomb load.
Projected development called for the use of two the forthcoming BMW 018A with 7,497 lbs. thrust in the Ju 287B-2. The V3 meanwhile was finishing completion when Russian forces captured the Junkers facilities. The Junkers estimates temporarily using six He S 011 engines were realistic enough. Estimated top speeds of 537 MPH at 16,400 feet and 487 MPH at 36,100 feet were expected with a range of 985 miles with 8,818 lbs of bombs. With a bomb load of 4,400 lbs. 1,325 miles could be flown. Time to 19,700 feet was to be 10.5 minutes while 32,800 feet would take 33.0 minutes. A ceiling of 47,398 feet could be reached.
The wings spanned 66 feet and the fuselage was 61 feet long including a tail barbette with two remotely fired 13 mm MG 131s. All up weight of the 3-seater was 47,398 lbs. while empty it weighed 26,278 lbs. It should be noted that a configuration with two pods of three engines below the wings was another possible arrangement projected.
As mentioned before, the Russians partially rebuilt the Junker Dessau complex to test their booty and later shipped it all to Moscow. They piddled with the V3 for years forth but did fly it in 1946 though with only four 004Bs making for a top speed of just 347 MPH and a ceiling of 35,433 feet. The German Professor Brunolf Baade's USSR work on the V3, called the Type 131, placed two 7,055 lb. thrust Lulko jets copied from the Rolls-Royce-Nene from Britain. Performance of the plane, which sported tanks at the tips of the forward swept wings, is unknown. Baade redesigned it with swept-back wings and it became the Type 140 and Type 150.
Looking at these designs illustrates the basis for every Soviet jet bomber decades hence. They are all continuations of the venerable Ju 287. It was no secret that the Russian design bureaus all studied the Ju 287 plus plans of similar craft. A glance at the 1947 IL-28, though not swept-wing, with two 6,040 lb. thrust Klimovs, drives it home. Its 580 MPH top speed and 41,000-foot ceiling in a 44,000-pound plane proves the Ju 287's potential was real. In a longer war the Ju 287 bomber would have reached production status.
This project shows the Russians directly using German aircraft and designers as springboards for a fast track to develop "their own" planes. The fact that they moved and rebuilt the Junker factory confirms they liked something about it that they didn't have.
When the Russians had milked the Germans dry they allowed them to return home in 1954.