FLIGHT TEST REPORT - MiG-25UP

Gary Aldrich and Stephen Henry

Originally published May 1995

["A what?!", you say? Yeah, a MiG-25! And our own EAA Chapter 1000 Member Gary Aldrich had the opportunity to flight test it. Although the flight test took place back in 1993, this is still the first time this report has been published--and it's in The Leading Edge, the official newsletter of EAA Chapter 1000. Boy, oh boy, do we have talent in EAA Chapter 1000, or what!?--ed]

Flight Briefing
General Observations, Ground Operations, Strap-In
Cockpit Evaluation
Flight Evaluation
Overall Evaluation

30 June 93
Zhukovsky, Russia
Aldrich/Sultanov
Henry/Sultanov
Fuel Load: 8 metric tons (17,600 lb)

This is a composite flight report combining the evaluations of both Lt Col Aldrich and Lt Col Henry who flew the aircraft the same day.

FLIGHT BRIEFING:

Maximum G limits: 2.8 > 6 metric tons of fuel, 3.0 < 6 metric tons
Maximum Mach: 2.8 for this trainer version
Gear limit speed: 500 Km/Hr
Prohibited maneuvers: all "over the top" maneuvers, stalls, tailslides
Rotate speed: 250-270 Km/Hr
Liftoff speed: 310-330 Km/Hr
Briefed Profile:

  1. Max A/B takeoff
  2. Climb at 600 Km/Hr to 8-10 Km
  3. Transfer trim to front cockpit for aileron rolls, level turns, minor maneuvering in pitch and possible "shallow loop" (low-G oblique loop).
  4. Transfer trim to rear cockpit for "Buran" approach setup
  5. Climb to 13-14 Km and accelerate to target velocity
  6. Buran approach to Zhukovsky main runway, full stop

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GENERAL OBSERVATIONS, GROUND OPERATIONS, STRAP-IN:

The aircraft is an "interceptor pilot training" variant with the instructor cockpit mounted below, and about five feet in front of, the normal cockpit. The RADAR is removed to make room for the instructor cockpit. Both evaluation crewmembers flew in this cockpit. The rear "normal" cockpit is configured as a standard MiG-25. Front cockpit canopy actuation is manual, hinged on the right side. The front cockpit occupant locks the canopy with a lever under the left sill after the crew chief lowers it to the rail. Both crewmembers received a thorough brief by a crew chief, accompanied by another maintenance person that spoke passable English. This was in contrast to the minimal brief for the previous day's flying and was probably driven by the near emergency Lt Col Aldrich experienced in the SU-17 high speed abort. Strap in to the MiG was straightforward as the harness is integrated with the seat. Shoulder straps and crotch straps met over the sternum where they were locked into a sturdy, but functional quick release buckle. After all connections are made, a ratcheting handle on the right side of the seat is actuated that tightens the harness. The shoulder straps can then be released from the locked position by pressing the lever on the left side of the seat to the right and aft. Oxygen and comm leads were identical to the SU-17, consisting of quick disconnect fittings secured to the harness with a small snap strap. As data would be collected for the Buran program, each crewmember was instructed in operation of the installed flight test data system. Cockpit controls for the system were mounted in a 2.5 in (h) x 10 in (w) panel mounted atop the glare shield, partially obscuring forward visibility. The controls consisted of ten toggle switches and four indicator lights. We were tasked to turn on the flight data recorder with the far left switch before taxi. The recording media for the system was contained in a large (10 in diameter) canister located below the main cockpit in a fuselage panel. The other switches we were allowed to touch were the trim transfer switch located in the center right of the main panel along with several other switches allowing instructor access to various systems; and the seat height adjust switch on the left cockpit sidewall. Engine start was conventional, using air pressure. The huge engines started quickly, with peak temperatures about 650 deg C. After receiving taxi clearance ("data on") we moved to the runway. Taxi did not appear to require unusual pilot skill and no rapid pedal inputs or wandering were noted. Just prior to runway entry we were held by a ground crewman with a red and white flag who did a cursory "last chance" inspection before waving us on to the runway for departure. One side note, Lt Col Henry shut down engines just after start because the alternate airfield was closed. This is very conservative since they had two runways and weather was only scattered clouds.

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COCKPIT EVALUATION:

The front, or instructor cockpit was generally comfortable and allowed excellent visibility in all directions except the four to eight o'clock positions which were blocked by the large headrest on the K-36 ejection seat. Both curved forward windscreen panels caused significant distortion when compared to the view through the oval center forward panel. This did not seem objectionable during the landing phase. Instrument arrangement was standard for the aircraft evaluated on this trip. Flight instruments were grouped on the left side of the forward instrument panel with engine and fuel instruments to the right. A combined VVI and turn/bank indicator enjoyed a central location immediately in front of the pilot with the standard Russian "outside-in" ADI located to its left. A large drum-digital DME readout was installed above the VVI and to the left of a telelight panel with about 15 indicators. A small (0.75 in dia.) red master caution light was located below and left of the telelight and was unmarked. The Mach meter on the lower left of the panel read from zero to 3.0. A navigation instrument similar to our HSI was situated below the ADI and provided course and bank steering bars. A "standby" airspeed indicator was provided on the bottom left of the panel that was plumbed directly to the pitot tube, apparently bypassing any air data computation. It is not known whether this feature was production representative. Pitch trim was accomplished by fore/aft actuation of a rocker switch atop the tall control stick (if trim "control" was in your cockpit). Roll and yaw trim switches were located on the left forward instrument panel. A button on the right throttle actuated an intercom of excellent audio quality. There was no provision for "hot mike". Another button aft of the intercom switch was for transmitting over the radio. There was a speed brake slide switch located below the communication buttons. The throttles could be locked in the afterburner (AB) range by separate finger lifts similar to the mechanism that provided protection from inadvertent engine shutdown. The gear handle was located under a set of indicator lights on the lower left sub panel and was not mechanically connected to the rear cockpit handle, remaining in the "down" position the whole flight.

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FLIGHT EVALUATION:

The pilot ran the engines up to 80% then moved the throttles to the AB range. There was no discernable AB lightoff and acceleration was not spectacular. Rotation (to about 10 degrees nose up) occurred around 250 Km/Hr with a large aft stick deflection with liftoff about 330 Km/Hr. We accelerated with a rapidly pulsating tone in our headsets to about 500 Km/Hr for climb. The tone is apparently analogous to the F4 AOA tone and is the only AOA indication available. The tone ceases as the gear were raised. Once in the work area the pilot told us to "take the trim" and we flew for about 5 minutes making 2g turns and aileron rolls in each direction. Aileron rolls were done at 500 and 750 Km/Hr. Stick forces and deflections were high. Maximum deflection rolls at 750 Km/Hr required about 60 lbs of lateral stick force (like pushing through molasses) and 8-10 inches deflection. The roll took 5 seconds at the lower airspeed and 6-7 seconds at the higher speed with no adverse yaw detected, though the nose did drop about 5-10 degrees below the horizon. Pitch forces were lighter, with 15-20 lb required for a 10 deg pitch change at the same airspeed. Turn performance was not evaluated due to the limited time available. The pitch damping was high and rates were comfortable with little overshoot. When asked to do a "shallow loop", the pilot said we did not have enough visibility with the clouds. Sultanov then took control to set up for the Buran approach. He lit the AB and accelerated in a 20 degree climb through the Mach and started a climb. He accelerated and S-turned to 1.3-1.5M while climbing to approximately 13.5 Km (very impressive climb performance). Initial climb rate was 5000 meters per minute. Fuel flow at this condition was about 15 metric tons per hour. The stick was held at nearly full aft travel all the while we were supersonic. Earlier, we were told that extended periods of supersonic flight are very tiring and are done on autopilot operationally. About 27 Km from the base, he retarded the throttles to idle and started down at about 1.2M. Initial VVI reading in the descent was 5000 meters per minute. He slowly bled this Mach number off until roughly 600 Km/Hr (subsonic) IAS then shutdown the left engine and descended on a 10-13 deg glidepath. Engine shutdown occurred at about 8 Km altitude. His aimpoint appeared to be the end of the runway and he made several adjustments with S-turns to lose energy. We began a flare at about 2000 meters and completed it just below 1000 meters and 500 Km/Hr. Below 500 Km/Hr the gear were extended. The rest of the flare and landing was normal, with touchdown at about 250 Km/Hr. Fuel remaining after the 0.5 Hr sortie was about 1 metric ton.

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OVERALL EVALUATION:

The MiG-25 is a classic "point design" interceptor. Developed to counter the threat from the American XB-70 (the Russians say its target was the SR-71) it is a prime example of brute force engineering. The huge Tumansky engines provide impressive speed and altitude performance and overcome crude aerodynamics. The flying qualities and maneuver performance are terrible by today's standards, but are not objectionable when evaluated against the design mission. It is interesting to note that Sultanov said the MiG-31 flying qualities have not been changed from the MiG-25. Likewise, limited all-aspect pilot visibility is not a drawback when the requirement is to do high-speed, high-altitude, ground-controlled intercepts. For a purely defensive role, the short legs of the aircraft would be adequate for a dash-shoot-return profile. The fact that this aircraft is used to develop their space shuttle landing profile provides an insight to the aerodynamic performance of that vehicle.

STEPHEN A. HENRY, Lt Col, USAF
Deputy Commandant
Flight Test Navigator

GARY L. ALDRICH, Lt Col, USAF
Director of Technical Support
Flight Test Engineer

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Contents of The Leading Edge and these web pages are the viewpoints of the authors. No claim is made and no liability is assumed, expressed or implied as to the technical accuracy or safety of the material presented. The viewpoints expressed are not necessarily those of Chapter 1000 or the Experimental Aircraft Association.
Revised -- 2 March 1997