R, R-1, R-2 by OKB-49 (G.M.Beriev)
|Based on article 'Flying boat R-1' by Alexandre Zablotsky, courtesy of Andrew I. Salnikov|
|Year||1947 (proj.)||1952 proto- type||1952 (proj.)|
|Takeoff Thrust (kg)||2200||2700||3100|
|Normal Thrust (kg)||2200||2400||2760|
|Weights (kg) and loads|
|Wing Load (kg/m2)||?||298 to 350||?|
|at 5000m||750 to 800||800||?|
|Maximum||2000 to 2500||2000||2400|
|Guns (nose)||fixed 2*23mm NR-23 100rpg|
|Guns (tail)||4*20mm||2*23mm Sh-3, 200rpg||2*23mm|
|Torpedoes||-||RAT-52 jet torpedo|
In mid-40s jet engines changed the face of military aviation. Jet powered fighters and bombers became dominant in airfleets of major military powers. G.M.Beriev decided to apply new technology to amphibians. He was inspired by success of S.V.Ilyushin and A.N.Tupolev with their projects '22' and '73'. There also was a pressure from the Naval Aviation Chief Commander E.N.Preobrazhenskij and Naval Forces Chief Commander N.G.Kuznetsov.
Despite the OKB-49 was busy with piston engine powered flying boat (Be-6), Beriev moved forward with development of jet powered reconnaissance flying boat. The aircraft planned as a flying boat (two-step hull) with high gull-shaped wing. Engines installed like on the Be-6 - at the wing bend, as far from the water surface as possible.Single tailfin carried high-placed tailplane. Aircraft had to carry 'Gals' type radar. Officially project started in May 1947.
Initiative of designer was supported by the Fleet Command. But shortly Naval Forces Chief Commander N.G.Kuznetsov (strong (strong proponent of the new plane) was arrested, and after unfair trial (1948) imprisoned.
Nonetheless, the Governmental Order (N°2061-803ss) was issued on June 12, 1948, laying out major technical characteristics of the 'Project R' (see table). Maritime flying boat reconnaissater, its should be able to serve as a bomber. Maximum speed of the aircraft was comparable to one of major USAF carrier-based jets (FH1 "Phantom" and F9F "Panther").
State trials were scheduled for December 1949. This date could not be met because designer team was too busy with the Be-6. Nonetheless, full-size mockup was built and presented to the Naval Forces representatives. On June 10, 1950 another Governmental Order (N°2747-974ss) followed. State trials date was moved to 1951. 'Nene' engines had to be replaced by more powerful domestic VK-1 and 20mm tail guns replaced by 23mm weapons.
Modified mockup was ready on March 24, 1951. Naval Forces representatives demanded to expand variety of bomb types and study opportunity to carry two AMD-500 mines. At that point the debate started around the range of the 'R'. G.M.Beriev insisted that they fulfilled demand of the Governmental Order, because the technical range was 2000km. Navy representative demanded practical range to be 2000km. This conflict plaqued whole history of the 'Project R'.
Finally, in November 1951, the first prototype designated 'R-1' was ready and rolled out for factory trials. Crew was seated in two pressurized cockpits. Pilot's canopy was shifted to the left side to improve downwards view. Pilot and navigator had ejectable seats. Gunner-operator had special escape hatch in the tail section. He remotely controlled tail cannons from any of two side blisters, equipped with aiming stations.
R-1 could be custom equipped by variety of day and night photoequipment, according to the mission goal. Cameras and hatches were operated by the navigator. He also had the top notch navigation equipment to perform flights in any weather conditions, day or night.
Long engine gondolas in open position could be used as a walks by ground/naval service crews to access engines. Rocket boosters could be installed to assist takeoff.
First taxi trials took place on November 24, 1951 with test-pilot of NII-15 VMS Colonel I.M.Sukhomlin. Standard pre-flight taxing had to be performed in speed range up to 0.7 of the takeoff speed. Aircraft performed well, but concerned test team decided to try higher speeds before first takeoff attempt. At 165km/h sudden longitudinal oscillation started. They were so powerful that the aircraft was pulled out of water. Once R-1 almost came to the 'tail-stand' and was saved only by instant reaction of experienced pilot.
New effect was called 'hydrodynamic instability threshold'. Fall 1951 and Spring 1952 (interrupted with freezing of the Azov Sea) was spend to cure the problems. First series of attempts (ailerons and elevator balancing, tailplane angle adjustment) brought no results. Then efforts were concentrated on the 'underbelly' effects. First hope was brought on May 24, 1952 by introducing of an air intake linked to drainage system, supplying air under fuselage between the hull steps. When this intake was open, longitudinal instability diminished and R-1 could taxi at speeds up to 196km/h.
Finally, test-pilot I.M.Sukhomlin and flight-mechanic S.I.Kondratenko brought R-1 into the air. This happened on May 30, 1952. Flight was 'spoiled' by tail vibration at speed above 270km/h and three minor 'jumps' during landing, but the first domestic jet hydroplane performed its first flight without accident.
In parallel the second aircraft of the R-type (R-2, see table) was under development. It differed by nose section, accommodating 'Kurs' radar in forward-extended fairing. Pilot cockpit was 'centered', navigator got more glazed cockpit. Nose guns separated from the pressurized cabin. R-2 had same hull, wing and tail, but carried more powerful and economical VK-5 engines. Technical range was increased to 2400km, but Naval Aviation Command insisted on 2400km to be a practical range (see comment). Actually all that was done on the R-2 was a mockup of the nose section...
Joint efforts of the OKB-49 and TsAGI were aimed against aircraft vibrations during flight and high speed taxi. The cause of taxi vibration was found - at high speed water jets blocked air access under the hull and resulted in strong depressions, 'sucking' aircraft tail down. But solving this problem took a long time...
On October 3, 1952 R-1 was flown by a 'newcomer' test-pilot G.I.Bourianov. During landing on speed 190km/h aircraft performed series of jumps (up to 4m into the air!) and made a deep dive. Eyewitnesses recall that only tail was visible. Maximum g-load 10.6 in the nose section was recorded. After repair just few taxis were performed before the Winter interrupted trials with the ice.
The project was completely out of schedule. And there were no warranty that all revealed problems will be solved in the nearest future. What was the worst, fast progress of jet aviation made the R-1 obsolete. It did not satisfy growing demands of Naval Aviation Command any more, and there were no easy ways to improve the design without radical changes.
On the special meeting (so called 'RAZBORKA POLIOTOV', after-flight briefing) in Moscow M.V.Khrunichev (than Minister of the Aviation Industry) suggested to close the 'R' project and disband the OKB-49. Position of more pragmatic officials (Minister of the Defence Industry D.F.Ustinov and Chief Commander of the VMS E.N.Preobrazhenskij) decided the situation in favor of G.M.Beriev.
Designer got new Governmental Order (N°2622-1105ss, October 8, 1953) for modern jet flying boat (what will materialize later as Aircraft 'M' or Be-10). The only built R-1 received a honorable duty to be an air- and hydrodynamics testbed for high-speed flying boat. Construction of the R-2 was cancelled.
Flights of the R-1 resumed on July 18, 1953. Aircraft had improved wing slats. Series of measurements revealed the under-hull area with the decompression maximum, and drainage channels were redirected to prevent this effect. Detailed study of under-hull pressure was performed. Fill-size mockup of new tail with swept tailplane was built, but remained a mockup.
Modified R-1 performed very well. No more problems were observed during takeoff (up to 200km/h) and landing (185km/h). It served as a Flying Laboratory and trainer until February 1956, when test-pilot M.Vlasenko performed an emergency landing at Gelendzhik Bay shallow parts, hitting the sea floor. R-1 was not repaired. It was seen standing for some time at the Gelendzhik Test Base.
|Created January 25, 1996
Modified October 23, 1998