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The Sukhoi T-4’s first flight took place on 22 August 1972. The T-4’s first flight was actually delayed due to forest fires that appeared around the Zhukhovskii airflield. The pilot was Vladimir Ilyushin and lasted for 40 minutes with the landing gear down (whichc stayed down for the next 5 flights of the aircraft). Here’s a video clip of the first flight and some of the subsequent flights.
The only problem that was encountered on this flight was heating of aft airframe section due to the engines. A steel heat shield was later added to fix this. The engines themselves performed well as did the fly-by-wire control system.
The T-4 underwent a total of 10 flights:
|5||4/19/1973||1 hr 24 mins|
|7||6/15/1973||1 hr 55 mins|
|8||6/26/1973||1 hr 16 mins|
|9||8/8/1973||1 hr 16 mins|
|10||1/22/1974||1 hr 1 min|
These flights revealed that the T-4 was easy to control on the ground. There was no tendency for the aircraft to pitch up during the takeoff run. Visibility from the cockpit was shown to be good. The T-4 handled relatively straightforward in level flight and approach and landing, with the auto-throttles and the fly-by-wire systems functioning as they should. The major issue during these flight tests was the excessive stick and rudder force needed to fly the T-4 when the backup flight control system was tested.
Construction on the second T-4 aircraft (called aircraft “102”) began in 1969 and completed in 1973. The first flight for 102 was scheduled for the 4th quarter of 1973. There were also plans for 3 more developmental aircraft. Aircraft 103 construction began in 1973 and was partially constructed by the time the T-4 was cancelled.
Stage 2 flight testing was to begin with the first aircraft (aircraft “101”) being used for system verification and high-speed performance and handling tests.
In the end, the Soviet Air Force decided to go with an improved version of the TU-22 (NATO code-named “Blinder”), which became the TU-22M (M = modified) (NATO code-named “Backfire”). It was felt that a modification of the Blinder was easier to do than to build a new aircaft. The Airforce also requested an increase in MiG-23 production.
Aircraft “101” went to the Airforce Museum as Monino in 1982 and parts of 102 went to the Moscow Aviation Institute but was eventually scrapped.
Sources and resources:
The Sukhoi T-4 is arguably called the “world’s first fly-by-wire” aircraft. It is however the first aircraft in Russia, to be built using titanium (like Lockheed’s SR-71 Blackbird).
Design configuration for the T-4 was finalized in December 1964 after extensive research done at TsAGI (the Central Aerohydrodynamic Institute, the Soviet counterpart to NASA) over the previous 2 years. The T-4 was do be a Mach 3+ so-called “strategic weapons system” i.e. a bomber, somewhat similar to the North American XB-70 (to which the T-4 bears a more than passing resemblance).
The Sukhoi T-4 (sometimes called the “Sotka” meaning 100) is 146ft 2in long and has a wing span of 72ft 2in (smaller than the XB-70) and is 36ft 9in tall. She weighs in empty 120,370lb. Loaded at 252,205lb (normal) or a maximum weight of 299,824lb. The wing has an area of 3,183 sq ft2.
The design performance specifications are as follows: Maximum speed was to have been 1,988mph (Mach 3.01). At sea level 715 mph (Mach 0.94). The service ceiling was 78,740ft with a range of 3,780 miles in the clean configuration. Take off and landing runs were 3,281ft and 3,117 respectively.
Overall, the structure of the T-4 used VT-20, VT-21L and VT-22 titanium alloys. As mentioned, the T-4 was the first aircraft in the Soviet Union to be constructed of titanium. VIS-2 and VIS-5 stainless steels were also used in the structure of the T-4. VKS-210 structural steel was used for fuel system piping and VNS-2 steel was used for hydraulic system piping.
The T-4’s flight control system consisted of a main, electro-hydraulic, fly-by-wire control system and a back mechanical system. The FBW system operated in 3 modes :
-a damper mode operating jointly with the mechanical control system.
-the takeoff and landing mode.
-the enroute mode.
The quadruplex FBW system had full authority but would automatically fail-over to the mechanical system if any of the 2 FBW channels failed. Each channel of the mechanical system was equipped with an automatic cable tension control unit and a changeover mechanism. The FBW and mechanical control system both had common artificial feel units and trimming mechanisms. Duplicate electromechanical actuators operated the canards via electrical signals from the pilot’s controls. All flights were done with the FBW control system switched on from the moment of takeoff.
The wing featured 0 degrees of anhedral. The inboard leading edge was angled at 75 degrees 44’. The outboard leading edge was angled at 60 degrees 17’. The wing’s thinkness/chord ratio was 2.7%. Both leading edges were fixed. Each wing also had 4 evelons (a combination of elevators and ailerons). There were also flapped canard foreplanes and a 2 part rudder.
The fuselage diameter was 20 inches. The nose could be drooped (for better crew visibility during takeoff and landing) to 12 degrees 12’ at speeds up to 435 mph. The nose was driven by screwjack driven hydraulic motors located behind the pilot. The first T-4 (aircraft serialed “101”) had a periscope for the pilot when the nose was fully raised. The cabin as fully pressurized and located behind the cabin was a refrigerated fuselage section containing the avionics. Behind that were 3 fuel tanks that carried a a total of 57 tonnes of fuel (a specially developed fuel called RG-1, a naphthyl fuel similar to JP-7)In the aft section of the fuselage, there is provision for braking parachute.
The fuel system was automated to maintain the T-4s center-of-gravity throughout the flight envelope. Production versions had provision for a ventral-mounted drop tank and air refueling recepticle.
Under the wing of the T-4 was a huge box containing the air inlet system and the RD-36 turbojet engines. The T-4 was powered by 4 Kolesov RD-36-41 turbojets each rated at 35,273lb in afterburner. The RD-36 has a specific fuel consumption of 1.94lbs/h at military power and 4.19lbs/h. The FBW system controlled the engines, the 3-section variable nozzles and the variable geometry air inlets. The T-4 had an automatic engine control system. For the most part it was used during decent and final approach phases to maintain speed. The system was doubly redundant and had built-in test equipment.
Each main landing gear had 4 twin tired wheels that retracted forward, rotating 90 degrees to lie on it’s side just outboard of the air inlet box. The nose gear has a levered suspension on 2 tires with wheel brakes and steering. The nose gear retracts backwards into a a bay between the engine ducts.
The T-4 has 4 autonomous hydraulic systems pressured at 3,980lb/in2. The aircraft also had a 400Hz 3 phase electrical system rated at 220/115V powered by 4 oil-cooled alternators each rated at 60kVa.
In part 2 I’ll cover the T-4 flight-test program.
I recently purchased this book after looking at a link in the Nep Lex Facebook group (another reason to join FB and the Group if you haven’t already). It’s been quite a while since I’ve been to the National Naval Aviation Museum and I thought it would be a good book to have at the coffee table.
I couldn’t be happier with this purchase, now granted I like all airplanes but I’ve got a special place in my heart for Naval Aviation.
The National Naval Aviation Museum: The Aircraft, is a 164 page color photo guide to most, if not all of the aircraft on display not only inside the Museum but, to my surprise and delight, displayed outdoors on their ramp as well.
Each page contains a color photo of the aircraft as its displayed in the Museum as well as a few pictures of the type as it appeared in service. I’m not a photog by any stretch but the photos are absolutely beautiful!
There’s a brief description of the aircraft and the role it played in the story of Naval Aviation. My favorite part of the book is the description of the individual aircraft history not many Museum book do that and this is one of the few. There’s also a small section for each aircraft containing the performance and specifications.
The book covers the entire gambit of Naval Aviation history from the beginning through both World Wars, The Cold War, Korea, Vietnam Desert Storm and many others. There’s a fascinating section that details aircraft current undergoing restoration at the Museum that made me wish they took more photos there 🙂
My ONLY nitpick is the picture of the F-16N to open the Vietnam War section of the book. The F-16N isn’t a Vietnam War era aircraft but hey, it in no way detracts from the book (I’m just kind of being a nerd here).
The National Naval Aviation Museum: The Aircraft, would also serve as a great reference for taking the Museum’s virtual tour.
The book is available for purchase, from the Museum’s Flight Deck Store for $15.00. A darn good value in my opinion AND you get to help the Museum.
If you like aviation in general (and especially Naval Aviation) I can’t recommend this book enough. The National Naval Aviation Museum: The Aircraft, is a welcome addition to my collection.
Most readers will already be familiar with the famed US Navy “graduate level” ACM program, TOPGUN (yeah, that’s one word, all caps) and the USAF’s Fighter Weapons School and the Red Flag exercises. During the Cold War did the Soviet Air Force have a similar program. That’s indeed the case and that the topic of this post.
Due to very poor showing of Soviet built aircraft in the 1967 Arab-Israeli War, the Soviet Union began a program generally known with the Soviet Air Force as The Center for Flight Personnel. The Center was located in Turkmenistan at an airbase called Maryy-1 (Maryy is pronounced “Marie).
Located at this base is a unit known as the 1521st Airbase unit. The 1521st consisted of 3 squadrons, 2 that would be considered “aggressor” units both flying the MiG-29 and an additional unit that operated the La-17 drone for target practice for the visiting Soviet Air Force units.
The squadrons of the 1521st was formed in 1974 and flew the MiG-21bis. Pilots for these squadrons contained a higher number of highly experienced pilots (distinctions of combat pilot experience in Soviet forces at the time were known as “First Class” and “Sniper” level pilots). These units had a higher proportion of these highly experienced pilot when compared to regular Soviet Air Force units.
Generally, the syllabus used by the units at Maryy-1 consisted of 5 parts:
-assessment of individual pilot skills.
-low level flying over the area’s featureless terrain for aircrew familiarization.
-ACM and QRA performance assessment.
-tactical excerises involving multiple aircraft.
-live missile launch and gunnery.
It should be noted that the Soviet Air Force had no TACTS system with which to provide real-time monitoring of aircraft involved in ACM (such as that used by the USAF and US Navy). All training was monitored in real time over the radio using a GCI from the 1521st and another controller from the visiting unit.
Soviet Air Force regiments’ results reflected on it’s graded readiness level and as expected getting a perfect score in the evaluation was very difficult.
The 1st Squadron of the 1521st initially flew the MiG-21bis and then the MiG-29 Fulcrum-C. The tips of the horizontal stabilator and the wingtips were painted yellow, with a black outline, to make the aircraft look like the F-15 Eagle. To keep up that appearance, angled black converging in a black and yellow chevron were applied aft of the cockpit. Sharkmouth markings were also added to aircraft based on ground crew preference.
The 2nd Squadron of the 1521st first flew the MiG-23MLD. There were plans to reequip the squadron with the Su-27 Flanker but instead received high-time MiG-29 airframes. These aircraft also featured sharkmouth markings with other marking consisting of a “sour-faced” hornet superimposed on a red lightning bolt with the letters “AM” (aviabaza Maryy, airbase Marie) above it.
After the collapse of the Soviet Union, the 2nd Squadron’s aircraft were transferred to the Kazakstan Air Force.
There really isn’t a lot of open-source information, either from books or the DTIC publication database. According to these sources there isn’t even references to these squadrons in Soviet defense publications.