Author Archives: Dario Leone

How the legendary Starfighter was used to train astronauts: the story of the NF-104

The story of how the Starfighter was used to train future astronauts.

Being the first operational aircraft able to reach and maintain a speed of more than Mach 2.0, the Lockheed F-104 was a huge leap forward when strictly compared to the contemporary subsonic jets.

Thanks to its performance, the Starfighter was chosen to train test pilots destined to fly the X-15, a winged spacecraft that was air-launched by a B-52 Stratofortress, flew into space and then landed conventionally.

The idea to modify several F-104As to serve as “manned spacecraft transition trainers” is credited to astronaut Frank Borman who was both student and instructor at Edwards Air Force Base, California, home of the Air Force’s Aerospace Research Pilot School, later renamed U.S. Air Force Test Pilot School.

The major modifications to the Starfighters consisted in the addition of a 6,000 pound thrust rocket engine at the base of the vertical tail, reaction control thrusters in the nose and in each wing tip, a larger vertical tail, increased wing span, tanks to store the rocket propellants, provision for a full pressure suit, a cockpit hand controller to operate the reaction control thrusters, and modified cockpit instrumentation.

Moreover, the unnecessary equipment, like the gun, fire control system, tactical electronics, and auxiliary fuel tanks, was removed.

The Starfighters with these modifications were renamed NF-104s. They entered in service in 1963 and their pilots could zoom to more than 100,000 feet in a full pressure suit, experience zero “g”, and use reaction control to handle the aircraft.

Only about 35 students had the privilege to fly the NF-104 and each pilot had to be prepared for these “space flights” by using standard Starfighters. The first mission was a pressure suit familiarization flight, with the F-104 flown to high altitude with the cockpit depressurized allowing the student to experience a flight in a fully pressurized suit. To practice the zoom profile, the second flight was conducted in a two-seat F-104, with the instructor that showed to the student how reaching an altitude of 70-80,000 feet performing a 30 degree climb, while the last three missions were made in a single seat Starfighter increasing the climb angle to 45 degrees and reaching an altitude of 90,000 feet.

After these five preparation flights, the student finally performed the two programmed NF-104 missions.

As described by Steve Markman and Bill Holder in their book One Of A Kind Research Aircraft A History Of In Flight Simulators, Testbeds & Prototypes, the typical flight syllabus started with taking off on jet power, climb to 30-40,000 feet, and accelerate to Mach 1.7-1.9. Then the pilot ignited the rocket engine and pitched the nose up to start the steep climb.

After two minutes the Starfighter passed through 80,000 feet, the jet engine flamed out, the rocket engine ran out of fuel and the pilot began a parabolic arc to the peak altitude.

It was during the parabolic arc that the pilot experienced “weightlessness” for about one minute and used the side stick to fire the reaction control rockets to control the aircraft’s pitch, roll and yaw motions.

Once at a lower altitude, the pilot restarted the jet engine and made a conventional landing: the whole mission lasted about 35 minutes from taxi to landing and was performed in a full pressure suit.

One NF-104 was destroyed on Dec. 10 1963. The plane was piloted by legendary Col. Chuck Yeager at that time the Aerospace Research Pilot School Commander. Yeager was attempting to reach an altitude record and after a 60 degree climb, while he was at 101,595 feet, the Starfighter experienced an uncontrollable yawing and rolling motion.

Yeager wasn’t able to recover the plane and was forced to eject at 8,500 feet.

During the separation from the ejection seat the rocket nozzle hit his face shield breaking it, while the combination of the red hot nozzle and oxygen in his helmet produced a flame that burned his face and set several parachute cords on fire.

Yeager was able to extinguish the flames with his glove hands and after the accident was hospitalized for two weeks.

The accident was depicted in the book (and film of the same name) “The Right Stuff”.

Col. Charles E. Yeager

Another NF-104 flight almost ended in disaster on June 15, 1971, when Capt. Howard Thompson experienced a rocket engine explosion while trying to lit it at 35,000 feet and Mach 1,15: luckily Thompson made a safe lading to Edwards AFB using the normal jet engine.

The program was terminated when it was decided that the aerospace training mission would be performed by NASA and the last NF-104 flight was performed in December 1971.

During its service with the U.S. Air Force the highest altitude reached by an NF-104 was 121,800 feet, achieved by Maj. Robert Smith during acceptance testing.

Today the last of the NF-104s is on static display in front of the Air Force Test Pilot School at Edwards AFB.

Image credit: U.S. Air Force

 

Here’s why the MiG-29 could defeat the best western fighters in close air combat, despite its limitations

Conceived to fill the technological gap between Russian and U.S. fighters, the MiG-29 has been one of the last cutting edge fighters produced by the then Soviet Union.

The Fulcrum was sold in large numbers to former Warsaw Pact air forces to replace their ageing MiG-23 Floggers and twenty four of them were also delivered to East Germany. The East German Jagdgeschwader (JG) 3 took delivery of its first MiG-29 in 1988, and on Oct. 4, 1990, the Wing operated 24 Fulcrums, equipping two squadrons.

A follow-on batch was on order, but the aircraft were never delivered.  After the end of the Cold War and following the re-unification of Germany, the Luftwaffe inherited some of these fighters making them as much “NATO-compatible” as possible.

Among the pilots that amassed experience at the controls of the Luftwaffe Fulcrums, there was the Oberstleutenant (the Luftwaffe rank equal to Lieutenant Colonel) Johann Koeck who, after flying the F-4 Phantom, became commander of the only Luftwaffe MiG-29 squadron.

Here is what Koeck recalls in Jon Lake’s book “How to fly and fight in the MiG-29 (Jane’s At the Controls)”:

“With the re-unification JG 3 became Evaluation Wing 29 on 1 April 1991. On 25 July 1991 the decision was taken to keep the aircraft and integrate them into the NATO air defense structure. JG73 was activated in June 1993, and the MiG-29s assumed a National (Day Only) QRA(l) commitment over the former East Germany. The MiG-29s moved to Laage in December 1993 and on 1 February 1994 the unit gained a NATO QRA(l) commitment.”

Being an experienced Fulcrum driver, Koeck can tell which were the weak and the strength points of the MiG-29.

The most obvious limitation of the MiG-29 was the aircraft’s limited internal fuel capacity of 3,500 kg (4,400 kg with a centerline tank). The MiG-29  had no air-to-air refueling capability, and its external tank was both speed and maneuver limited.

If a mission started with 4400 kg of fuel, start-up, taxy and take off took 400 kg, 1,000 kg were required for diversion to an alternate airfield 50 nm away, and 500 kg for the engagement, including one minute in afterburner, leaving only 2,500 kg of fuel.

Koeck explains that “If we need 15 minutes on station at 420 kts that requires another 1000 kg, leaving 1500 kg for transit. At FL 200 (20,000 ft) that gives us a radius of 150 nm, and at FL 100 (10,000 ft) we have a radius of only 100 nm.”

The Fulcrum’s limited range conditioned also how the aircraft could perform a specific mission: in fact the MiG-29s didn’t possess the range to conduct HVAA (High Value Airborne Asset) attack missions, and they were effectively limited from crossing the FLOT (Front Line of Own Troops).

This limited station time and lack of air-to-air refueling capability ruled the MiG-29s out of meaningful air defense missions.

Another limitation of the aircraft was its radar that, as Koeck explained, was at least a generation behind the AN/APG-65, and was not line-repairable: if a MiG-29 experienced a radar problem, the aircraft went back into the hangar.

The radar had a poor display, giving poor situational awareness, and this was compounded by the cockpit ergonomics. The radar had reliability and lookdown/shootdown problems, hence  its poor discrimination between targets flying in formation, and moreover it couldn’t lock onto the target in trail, only onto the lead.  

Mig-29 GAF air-to-air

Due to these limitations the integration in the NATO environments of the Luftwaffe MiG-29s was really hard and restricted to only few roles: as adversary threat aircraft for air combat training, for point defense, and as wing (but not lead) in Mixed Fighter Force Operations.

Nevertheless the onboard systems were still too limited, especially the radar, the radar warning receiver, and the navigation system. These restrictions brought to several problems that the Fulcrum pilots faced in tactical scenarios, such as a  poor presentation of the radar information (which led to poor situational awareness and identification problems), a short BVR weapons range and a bad navigation system.

But despite all these limitations, once the furball started, the Fulcrum was the perfect fighter to fly. In fact thanks to its superb aerodynamics and helmet mounted sight, the MiG-29 was an exceptional fighter for close-in combat, even compared to aircraft like the F-15, F-16 and F/A-18.

As Koeck recalls “Inside ten nautical miles I’m hard to defeat, and with the IRST, helmet sight and ‘Archer’ (which is the NATO designation for the R-73 missile) I can’t be beaten. Even against the latest Block 50 F-16s the MiG-29 is virtually invulnerable in the close-in scenario. On one occasion I remember the F-16s did score some kills eventually, but only after taking 18 ‘Archers’ (Just as we might seldom have got close-in if they used their AMRAAMs BVR!) They couldn’t believe it at the debrief, they got up and left the room!”

Moreover with a 28 deg/sec instantaneous turn rate (compared to the Block 50 F-16’s 26 deg) the MiG-29 could out-turn them: in fact the Fulcrum retained an edge over its adversaries thanks to its unmatched agility which was reached combining an advanced aerodynamics with an old-fashioned mechanical control system.

After one of the German Fulcrums was sold for evaluations to the U.S. in 1991, the remaining 22 MiG-29s served until 2003, when they were sold to Polish Air Force for the symbolic sum of 1 Euro each.

Those Mig-29s were then upgraded and they currently provide Baltic Air Policing duties against the Russian threat in northern Europe.

Image credit: U.S. Air Force

 

A quick look at why the F-16N was the best plane to simulate soviet “bandits” in adversary missions.

The Lockheed Martin F-16 Fighting Falcon is the western world’s most prolific fighter of the last 40 years.

Even if medium and long-range air-to-air missiles, such as the AIM-7 Sparrow and the AIM-120 AMRAAM,  have been integrated in the F-16 since 1986 for BVR (Beyond Visual Range) engagements, the Viper (the universal F-16’s nickname) was born in response to LWF (Light Weight Fighter) program, for a small and agile fighter: the U.S. Air Force needed a small, cheap, maneuverable airplane to flank the F-15 Eagle, its air superiority fighter, and face the small Soviet fighters, such as the MiG-21 in close combat.

Indeed the Viper can maneuver against any opponent, proving to be the ideal adversary (or “aggressor” in the Air Force jargon) aircraft for both U.S. Air Force and U.S. Navy training programs. Arguably the best version of the Fighting Falcon having played the bandit role has been the F-16N.

Born in response to the need of the Navy to replace its aging fleets of A-4 Skyhawks and F-5 Tigers adversary fighters, the F-16N was a basic F-16C Block 30 with the General Electric F110-GE-100 engine.

The F-16N was typically equipped with the Air Combat Maneuvering Instrumentation (ACMI) pod on the starboard wingtip and to completely simulate adversaries, the ALR-69 Radar Warning Receiver (RWR) and the ALE-40 chaff/flare were also incorporated.

To save weight the internal cannon was removed and the aircraft could not carry air-to-air missiles, even though it retained the APG-66 radar from the F-16A/B models.

Twenty two single seat F-16Ns along with four two seat TF-16Ns were delivered in the late 1980s to the Navy and four units flew the jet: the VF-126 Bandits and the Fighter Weapons School both based at Naval Air Station (NAS) Miramar, the VF-45 Blackbirds based at NAS Key West and the VF-43 Challengers based at NAS Oceana.

According to Rick Llinares & Chuck Lloyd book Adversary America’s Aggressor Fighter Squadrons, since the U.S. Navy didn’t own any Fulcrum or Flanker, the F-16N was the best fighter to replicate the then new fourth generation Russian fighters and finally F-14 and F/A-18 crews could fight against a real different aircraft. In particular, against the Tomcat, the nimble F-16N was a very challenging adversary, as by the video below.

Unfortunately the F-16N began to experience the wear and tear due to the excessive g’s sustained during many aerial engagements and in 1994 the Navy decided to retire the type since the costly repair to keep the Viper flying can’t be afforded. But even if as bandit the F-16N was replaced by the F-5 which was the fighter the Viper intended to replace, the F-16N still remains the best adversary fighter ever flown by the U.S. Navy.

The U.S. Navy Naval Strike and Air Warfare Center, at NAS Fallon, Nevada, currently operates some F-16A in the aggressor role, like the one in the image below.

F-16N Giovanni Colla

Image credit: Giovanni Colla. Top Image: National Naval Aviation Museum FB page.

 

The amazing story of Bill Weaver: the Blackbird pilot who survived his SR-71 disintegration

The incredible story of a lucky SR-71 pilot who survived to a Blackbird disintegration at Mach 3+

Built as a strategic reconnaissance aircraft able to fly at 88,000 feet and Mach 3, the iconic Lockheed SR-71 required aircrews to wear a special silver pressure suit to ensure their safety. This proved to be much useful during the time, as the aircraft experienced several accidents at very high speeds and altitudes during its test flights.

The protection provided by these suits was put to test on Jan. 25, 1966 when Blackbird tail number 952 disintegrated mid-air during a systems evaluation flight. The mission was intended to investigate procedures designed to reduce trim drag and improve high Mach cruise performance while the center of gravity (CG) was located further aft than normal, reducing the Blackbird’s longitudinal stability.

The SR-71 was driven by Bill Weaver with a Lockheed flight test specialist, Jim Zwayer in the back seat and it took off from Edwards AFB at 11:20 am . They refueled from a KC-135, accelerated to Mach 3.2 and climbed to 78,000 feet, which was their initial cruise altitude.

During a programmed thirty-five-degree bank right turn they experienced an “inlet unstart” that caused the immediate unstart on the right J-58 engine, forcing the aircraft to roll further right and start to pitch up. An inlet unstart happened when a shock wave was rapidly ejected back outside the inlet. When an inlet unstart occurred a device called the cross-tie system was enabled to minimize the extreme rolling and yaw of the aircraft and to prevent the good inlet from unstarting. At the same time the cross-tie system also restarted the good engine. As Weaver himself told to former Blackbird pilot Col. Richard H. Graham in his book, “SR-71 The Complete Illustrated History of THE BLACKBIRD The World’s Highest, Fastest Plane”: “I jammed the control stick as far left and forward as it would go. No response. I instantly knew we were in for a wild ride.”

Since the chances to survive an ejection at Mach 3.18 and 78,000 feet weren’t very good, Weaver and Zwayer decided to stay with the aircraft to restore control until they reached a lower speed and altitude, but the cumulative effects of system malfunctions exceeded flight control authority. Everything seemed to unfold in slow motion, even if the time from event onset to catastrophic departure from controlled flight was only two to three seconds.

Weaver recalls that he was “still trying to communicate with Jim, I blacked out, succumbing to extremely high g-forces. Then the SR-71 literally disintegrated around us.”

Weaver struggled to realize what was really happening. “I could not have survived what had just happened. I must be dead. As full awareness took hold, I realized I was not dead. But somehow I had separated from the airplane. I had no idea how this could have happened; I hadn’t initiated an ejection. The sound of rushing air and what sounded like straps flapping in the wind confirmed I was falling, but I couldn’t see anything. My pressure suit’s face plate had frozen over and I was staring at a layer of ice.”

It was at that point that the pressure suit proved to be very effective protection for Weaver. In fact, once it was inflated, an emergency oxygen cylinder in the seat kit attached to the parachute harness was functioning. It not only supplied breathing oxygen, but also pressurized the suit, preventing Weaver’s blood from boiling at the extremely high altitude. In this way the suit’s pressurization had also provided physical protection from intense buffeting and g-forces. That inflated suit had become like a tiny escape capsule.

Another system conceived to safeguard the Blackbird aircrew during the bailout procedure was the SR-71’s parachute system. To prevent body tumbling motions and physical injury due to the centrifugal forces it was designed to automatically deploy a small-diameter stabilizing parachute shortly after ejection and seat separation.

Since Weaver had not intentionally activated the ejection sequence, he thought that stabilizing chute might not have deployed. But he quickly determined he was falling vertically and not tumbling, meaning that the little parachute had deployed and was doing its job. The next concern was for the main parachute, which was designed to open automatically at 15,000 feet, but again he had no assurance the automatic-opening function would work. So Weaver decided to open the faceplate, to estimate his height above the ground but as he reached for the faceplate, he felt the reassuring sudden deceleration of main parachute deployment.

After landing, Weaver was rescued by Albert Mitchell Sr., owner of a ranch in northeastern New Mexico, who helped him with the chute, then reached Zwayer who had landed not far away, with his own Hughes helicopter. Mitchell returned few minutes later reporting that Zwayer was dead: in fact he had suffered a broken neck during the aircraft’s disintegration and was killed almost instantly. Moreover Mitchell said that his ranch foreman would watch over Zwayer’s body until the arrival of the authorities and he flew Weaver to the Tucumcari hospital.

Investigation of the incident determined that the nose section of the Blackbird had broken off aft of the rear cockpit and crashed ten miles from the main wreckage. The resultant very high g-forces had literally ripped Weaver and Zwayer from the airplane. After this crash, testing with the CG aft of normal limits was discontinued, and trim-drag issues were resolved via aerodynamic means. Moreover the inlet control system was improved and the inlet unstarts almost stopped with the development of the Digital Automatic Flight and Inlet Control System.

Two weeks after the accident Weaver was back in a Blackbird. As he recalls: “It was my first flight since the accident, so a flight test engineer in the back seat was probably a little apprehensive about my state of mind and confidence. As we roared down the runway and lifted off, I heard an anxious voice over the intercom. “Bill! Bill! Are you there?” “Yeah George. What’s the matter?” “Thank God! I thought you might have left.” The rear cockpit of the SR-71 has no forward visibility – only a small window on each side – and George couldn’t see me. A big red light on the master-warning panel in the rear seat had illuminated just as we rotated, stating: “Pilot Ejected”. Fortunately, the cause was a misadjusted micro switch, not my departure.”

DF-ST-89-06278

Image credit: U.S. Air Force

 

The F-14 Tomcats that never were vs F/A-18E/F Super Hornet: who would have won?

Several years since it was eventually retired from the U.S. Navy, the Grumman F-14 Tomcat remains one of the most loved planes by aviation enthusiasts.

Any article about this iconic fighter plane, still operating with the Islamic Republic of Iran Air Force, its story, capabilities, records and surrounding anecdotes, always become a much debated and commented post on The Aviationist. For this reason, we will continue writing about this legendary plane and its replacement: the F/A-18E/F Super Hornet.

After the Tomcat retirement, the Rhino (as the F/A-18E/F is nicknamed by its aircrews) has not only quickly become the backbone of every Carrier Air Wing (CVW), but it has also replaced some of the oldest Legacy Hornets on the American flattops. Having fulfilled such a difficult task, the Super Hornet has demonstrated to be one of the best multirole jets available today. But could an advanced version of the F-14 have been even better?

LCDR Joe “Smokin” Ruzicka, who was the Radar Intercept Officer (RIO) who flew the last F-14 Demonstration before the Tomcat’s retirement in 2006, last year released an interesting interview to Foxtrot Alpha’s Tyler Rogoway. Among all the other things, Ruzicka explained that, while the Super Hornet is a great plane, it seems like its strength mainly comes from technology. “In the Tomcat, I think you had to be a better aviator because the technology just wasn’t there. It was up to the aircrew to maximize its performance (or minimize it if you sucked).”

That said, one might wonder whether integrating the same technology in the F-14 would have been possible.

By 1987, Grumman realized that the potential for growth had not yet been reached by the F-14 airframe, and they proposed to the U.S. Navy four advanced versions of the F-14, as told by Tim Callaway in Issue 13 “Grumman F-14 Tomcat” of Aviation Classics magazine.

The F-14D Quickstrike was the first proposal: featuring an enhanced version of the APG-71 radar, this advanced Tomcat version would have carried stand off weapons such as the Harpoon, HARM and SLAM (Standoff Land Attack Missile) missiles.

Requiring only new software and minor modifications to existing F-14Ds, the Quickstrike would have been a cost-effective attack platform but it didn’t meet the Advanced Tactical Fighter specification and the U.S. Navy chose the shorter ranged F/A-18E/F.

The second proposal was the ST21, the Super Tomcat for the 21st Century. The latter would have been a structural upgrade to the existing F-14Ds, that would have introduced a new wing glove design and single piece windscreen, while sensors positioned in front of the under fuselage weapons rails would have supplemented the chin pods. Moreover the ST21 would have also received a new engine the F110-GE-129 of 13,154kg of thrust, which would have provided a supercruise speed of Mach 1.3 featuring also thrust vectoring nozzles for greater maneuverability. These new engines would have supplied to the ST21 a tremendous acceleration alongside with a greatly increased range of the aircraft.

Another modification to the standard F-14D would have been the AST21, the Attack Super Tomcat for the 21st Century.

This advanced Tomcat would have been fitted with additional extra bomb pylons under the engine nacelles, a nuclear weapons capability, a modified radar with a Forward Air Controller (FAC) mode and an Integrated Defensive Avionics Package (IDAP) to improve survivability in the air to ground environment. The last proposal, as Callaway explains, was the ASF-14 Advanced Strike Fighter.

The ASF-14 would have been a totally new aircraft with the F-14 shape and it would have taken advantages of the new materials and new technologies developed for the Advanced Tactical Fighter and Advanced Tactical Attack Aircraft programs.

None of these proposals has been built and we’ll never know if an advanced Tomcat would have been better than the actual Super Hornet, but for sure these two fighters are two different aircraft as explained by Ruzicka, who told to Rogoway that the better way to understand the differences between the F-14 and the F/A-18E/F is using the analogy of a muscle car to a mini-van, “with the Tomcat being the former and the Super Hornet being the latter. The muscle car doesn’t have much to it in the way of fancy technology, just some raw speed and the coolness of a Steve McQueen movie, but it gets the job done. The mini-van on the other hand is a very nice car, complete with DVR’s for the kids, Air Conditioning, power windows, and lots of places to put your sippy cup. It’s a great car—-but it’s still a mini-van.”

Image credit: U.S. Navy