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#1
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Blackbird v. Mig-25
Aircraft Speed Altitude Mach Number
SR-71 Blackbird 2,275 mph (3,660 km/h) 80,000 ft (24,385 m) Mach 3.35 MiG-25 2,110 mph (3,390 km/h) 42,650 ft (13,000 m) Mach 3.2 This data is from Aerospaceweb. Question: SR-71 looks like alien plane, have very special design (incl tanks what start to keep fuel on flight only)etc etc. Mig-25 looks as pretty usual plane. But difference in speeds is relative minor, expecially if to look at what altitude it is reached. How it is possible? Do anybody have more data? Say, about SR-71 performance at 40 000 feet? |
#2
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Vello Kala wrote:
Aircraft Speed Altitude Mach Number SR-71 Blackbird 2,275 mph (3,660 km/h) 80,000 ft (24,385 m) Mach 3.35 MiG-25 2,110 mph (3,390 km/h) 42,650 ft (13,000 m) Mach 3.2 This data is from Aerospaceweb. Question: SR-71 looks like alien plane, have very special design (incl tanks what start to keep fuel on flight only)etc etc. Mig-25 looks as pretty usual plane. But difference in speeds is relative minor, expecially if to look at what altitude it is reached. How it is possible? Do anybody have more data? Say, about SR-71 performance at 40 000 feet? Most reports I've read said the Mig-25 could only do over Mach 3 for a very short period of time, and it destroyed the engines in doing so. With no comments on its veracity, see, for example: Mig-25 PERFORMANCE: Max permitted Mach No. at height: Mach 2.83 Max level speed at 13000 m (42,650 ft): 1,620 knots 3,000 km/h 1,865 mph at S/L: 647 knots (1200 km/h; 745 mph) Max cruising speed at height: Mach 2.35 Econ cruising speed: Mach 0.85 Service ceiling: 21,000 m (68,900 ft) The MiG-25 that was clocked at Mach 3.2 by the Israelis achieved this speed while running from an intercepting F-4 (which can barely manage Mach 2 on a good day--before running out of fuel). Upon landing, both engines in the MiG had to be replaced. Victor Belenko, the Foxbat pilot who defected in 1976, stated that the top speed of the MiG-25 was Mach 2.8, but flight above Mach 2.6 was difficult because of a tendency of the engines to overspeed. Victor related that MiG-25 pilots were in fact restricted to flying below Mach 2.5 except with special permission. - http://www.espacetickets.com/foxbat.htm |
#3
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"Vello Kala" wrote in message ... Aircraft Speed Altitude Mach Number SR-71 Blackbird 2,275 mph (3,660 km/h) 80,000 ft (24,385 m) Mach 3.35 MiG-25 2,110 mph (3,390 km/h) 42,650 ft (13,000 m) Mach 3.2 This data is from Aerospaceweb. Question: SR-71 looks like alien plane, have very special design (incl tanks what start to keep fuel on flight only)etc etc. Mig-25 looks as pretty usual plane. But difference in speeds is relative minor, expecially if to look at what altitude it is reached. How it is possible? Do anybody have more data? Say, about SR-71 performance at 40 000 feet? You only think the engine performance is similar. The SR-71 could maintain Mach 3-plus for several hours at a time, but the MiG-25 could do mach 3.2 for only about 5 minutes before burning the engines up. |
#4
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You are comparing one performance parameter on two entirely different types of
aircraft. It doesn't matter what the SR's speed is at 40,000' -- it doesn't fly there. How good of imagery coverage can the MiG 25 provide, from 90,000'? Apples and oranges. A better question would be, how many times did a MiG 25 manage to catch the SR? v/r Gordon ====(A+C==== USN SAR Its always better to lose -an- engine, not -the- engine. |
#5
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In article ,
"Vello Kala" writes: Aircraft Speed Altitude Mach Number SR-71 Blackbird 2,275 mph (3,660 km/h) 80,000 ft (24,385 m) Mach 3.35 MiG-25 2,110 mph (3,390 km/h) 42,650 ft (13,000 m) Mach 3.2 Standard Admonition - beware of the data. Context is everything, and there's not enough there. This data is from Aerospaceweb. Question: SR-71 looks like alien plane, have very special design (incl tanks what start to keep fuel on flight only)etc etc. Mig-25 looks as pretty usual plane. But difference in speeds is relative minor, expecially if to look at what altitude it is reached. How it is possible? Do anybody have more data? Say, about SR-71 performance at 40 000 feet? SR-71's don;t fool around at a mere 40,000'. The purpose of the SR-71 is to carry a set of reconnaisance sensors at Mach 3+ at 80,000+ ft (Mostly plus) for several hours. (Acturally, take off, top up from a tanker, cruise out a Mach 3+/80K+ for a couple hours, hit another tanker, Mach 3+ for another couple hours, all the way to wherever and back. (Oh, yeah, all while having a radar signature equivalent to a glider) Prepping an SR-71 for flight takes hours. It has a lot of exotic materials and systems, and is more akin to a spaceship than a normal airplane. I requires special fuels special lubricants and hydraulic fluids, and weird stuff like TriEthyl Borane to keep the fires lit. It flies in a delicate balance of shockwaves, all expertly positioned to provide balanced flight and peak performance. A MiG-25 is a bomber interceptor (Although it did find secondary roles as a recon airplane and a bomber). It's intended to sit at the end of a runway, make a scramble takeoff, and roar straight at an incoming B-58, guided by a data link from its GCI (Ground Control Intercept) site, and shooting the bomber in the face with large Air-to-Air missiles, and return directly to its base. (Many accounts claim that the MiG-25 was intended to intercept B-70s, the Mach 3 Bomber that North American built in the late 1950s adn early 1960s, and which never went into service. I, quite frankly, doubt it, Even with the B-70's huge radar signature, its closing speeds would be so fast that a minor course change by the bomber wouldn't be able to be countered by the MiG, (Or if the B-70 wasn't kind enough to fly straight at the MiG's base) and the MiG didn't have any speed advantage in the almost inevitable tail chase that would result. It does, however, have the perfect performance envelope for taking on a Mach 2, 60,000' airplane like a B-58.) The MiG was intended to be flown by normal service pilots, use normal fuels and systems, and be maintained by 20 year old conscripts in Siberia. Making an airplane that can do all those things wasn't a trivial acheivement. Another way to look at it is that the MiG-25 has pretty much the ultimate perforance that can be acheived with a normal shape, and fairly normal materials. (Stainless Steel, for the most part) If you're going to go faster and higher, you need to start making exotic airplanes like the SR-71. -- Pete Stickney A strong conviction that something must be done is the parent of many bad measures. -- Daniel Webster |
#6
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The advertised max speed of the Mig 25 is 2.83, The SR-71 design limit was
3.2, but 3.3 was attainable. The 3.2 number attributed to the Mig was based on radar tracking data (not exactly precise and subject to wind errors). The Mig dashed to that speed, the SR lived there. Big difference. R / John |
#7
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Here MiG-25 goes again... mixture of old 70-80'es data.
The story about burning engines is from that date. The published story is that test-pilot Bezevec on the pre-production MiG-25R went beyond M3 because he was painted by Hawk missile radar. In that time '25 was still in test-phase with limited max speed endurance and when arrived to Egypt it was just cleared from 3min flight to 8min. While in Egypt, it was cleared further to 40 min up to unlimited when necessary. MiG-25 engines have Chekunov's electronical system for fuel and engine RPM management-the FADEC forerunner. There was a MiG-25 version that could "normally" travel up to M3.2 known as MiG-25M, but was abandoned late in development in favour of MiG-25MP (known as MiG-31 today). However, it was this MiG25M prototype that under a "official" name tangled with F-15 Streak Eagle in speed, height and speed to height records. Cruising speed (in terms of best range/perfomance/economics) is around 2.500 km/h, NOT M 0.85-it is another blunder or a mix-up with MiG-31 (MiG-25 RB-15-300 engines are awfully inefficient subsonically). Another mix-up or disinformation is that MiG-25 cannot travel more than M 2.3 with four R-40 missiles-actually, it can carry them up to the placarded (M 2.83) limit (MiG-25P/PD/PDS interceptors) or even four 500kg bombs (RB/RBS/RBT recce/strike versions) up to that speed. The speed of the MiG-25 at low-level is limited by a pressure that is simply too high at such low altitudes, so the temperature at the inlet (as well as in the engine) raises above limits. Although MiG-25 looks ordinary and extremely "boxy", its shape is very efficient for high-mach regime. It is a different approach than one in SR-71. While SR-71 had fuel tanks that got sealed by the airfame stretching, MiG-25 has inboard tanks separated from the airfame-just like a car fuel reservoirs (with a difference that it's tanks are pressured, filled with inert gas and cooled). MiG-25 can produce up to 5g (or 5.5) in supersonic regime. Sustained altitude is around 20,000 m. SR-71 can manage around 2g (which is no discredit, because it was not necessary for SR-71 to turn better). Now, comparing MiG-25 and SR-71 is comparing apples and oranges. MiG-25 project was initialized to -counter- a Blackbird (not Valkirye as many sources described!). Later (but early in develoment), it was "split" to produce both inteceptor and recce variant . SR-71 is strategic recce aircraft (although it evolved from A-12 that further produced a basis for both SR-71 recce aircraft and YF-12 interceptor). MiG-25 is quite limited in range, SR-71 is not. SR-71 had much wider and sophisticated recce equipment than MiG-25R and could travel at M3+ until ran out of gas. MiG-25 was produced massively (in order of around 600 aircraft), SR-71 just a handful. Nele NULLA ROSA SINE SPINA Ragnar wrote in message ... "Vello Kala" wrote in message ... Aircraft Speed Altitude Mach Number SR-71 Blackbird 2,275 mph (3,660 km/h) 80,000 ft (24,385 m) Mach 3.35 MiG-25 2,110 mph (3,390 km/h) 42,650 ft (13,000 m) Mach 3.2 This data is from Aerospaceweb. Question: SR-71 looks like alien plane, have very special design (incl tanks what start to keep fuel on flight only)etc etc. Mig-25 looks as pretty usual plane. But difference in speeds is relative minor, expecially if to look at what altitude it is reached. How it is possible? Do anybody have more data? Say, about SR-71 performance at 40 000 feet? You only think the engine performance is similar. The SR-71 could maintain Mach 3-plus for several hours at a time, but the MiG-25 could do mach 3.2 for only about 5 minutes before burning the engines up. |
#8
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"Peter Stickney" wrote in message ... The MiG was intended to be flown by normal service pilots, use normal fuels and systems, and be maintained by 20 year old conscripts in Siberia. Making an airplane that can do all those things wasn't a trivial acheivement. Another way to look at it is that the MiG-25 has pretty much the ultimate perforance that can be acheived with a normal shape, and fairly normal materials. (Stainless Steel, for the most part) If you're going to go faster and higher, you need to start making exotic airplanes like the SR-71. Thank you all for making things clear! One more strange thing: russians have a lot of titanium, they even built submarine hulls from that - strange airframe builders in SU find so little use for titanium. Do anybody know the reason? -- Pete Stickney A strong conviction that something must be done is the parent of many bad measures. -- Daniel Webster |
#9
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$$$
despite it's relative abundance, titanium is very difficult (and thus costly) to manufacture and machine. "Vello" wrote in message ... Thank you all for making things clear! One more strange thing: russians have a lot of titanium, they even built submarine hulls from that - strange airframe builders in SU find so little use for titanium. Do anybody know the reason? |
#10
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"Vello" wrote:
Thank you all for making things clear! One more strange thing: russians have a lot of titanium, they even built submarine hulls from that - strange airframe builders in SU find so little use for titanium. Do anybody know the reason? Yes, the earlier varieties of Ti were extremely difficult to handle and work. Minor contamination with Chlorinated solvents can lead to rapid and catastrophic corrosion, for example. Many specialized techniques had to be developed by Lockheed (and presumably were similarly developed later for the Alfa subs), before Titanium fabrication could be used for so much of the aircraft. |
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