Saab’s contender for the title ‘European Fighter of Choice’ has been flying for a little over six months. Jerry Gunner spoke to the Swedish company’s chief test pilot, Hans Einerth, to find out how the test programme is progressing
MILITARY GRIPEN E
There are arguably four key warplane programmes in Western Europe. The longestablished Typhoon and Rafale have been in service for many years and are only now approaching maturity with the introduction of active electronically scanned array (AESA) radars and advanced missile systems. America’s F-35 Lightning II, in which many European nations have invested heavily, has yet to enter service fully with any non-US air arms. The US Marine Corps F-35B was declared to have achieved initial operational capability in July 2015 and the US Air Force’s F-35A in August 2016. The other contender for the title, a product from non-NATO member Sweden, is, of course, Saab’s Gripen E multi-role fighter. Many might think the Swedish project is old hat, with the first Gripen flying as long ago as December 1988; but the jet has already gone through one major transformation that saw early Gripen As and Bs replaced by much more capable C and D models and the trend continues with the new kid on the block. Such is Saab’s reputation for producing high-quality, affordable products that the conglomerate has already achieved its first overseas sale – 36 jets to Brazil – as well as a commitment from Sweden itself to buy 60.
Preparing for the test programme
The first Gripen E to fly, known as test vehicle eight based on its manufacturer’s serial number, 39-8, made its first flight over Östergötland near Saab’s test airfield at Linköping in the hands of test pilot Marcus Wandt on June 15 this year. Upon landing, he said: “The flight was just as expected, with the aircraft performance matching the experience in our simulations.” He singled out the aircraft’s acceleration and smooth handling for particular praise.
As testing progresses 39-8 will be joined by two others of the type, but it is already accompanied by a specially built test vehicle. Saab JAS 39NG Demo 39-7 was converted from a redundant JAS 39B (s/n 39803). It has been flying in its new guise for nearly a decade and will be familiar to visitors to air shows. Rebuilt from the ground up, it features the Gripen E’s General Electric F414G turbofan engine, as well as many of the new jet’s systems, including its AESA radar and infrared search and track (IRST) sensor. The front seat avionics have not been changed to replicate the new version of Gripen, but the back one has. This saves money and improves safety – the front-seater does not have to be qualified on Gripen E – although one still has to be a test pilot to get the job, of course. The pilot’s colleague flies the aircraft using Gripen E’s systems.
Stretching the boundaries
Hans Einerth oversees Saab’s military air operations and bears the title Wing Commander Flying. As such, he is the boss of seven other test pilots working for Saab. He told AIR International about the progress so far in the Gripen E test programme: “I have not yet personally flown the Gripen E,” was his first revelation, “but I have flown as a chase pilot and in our test centre. I am quite familiar with the test programme.”
This was the first of many selfdeprecatory statements in the interview. Einerth is not one to blow his own trumpet and one gets the impression that every word is carefully considered. Before leaving the Svenska Flygvapnet (Royal Swedish Air Force) as a Lieutenant Colonel in 2013, he was head of its test centre – Försökscentralen – also at Linköping, working on Gripen development.
Describing the aims of the flight test programme, Einerth said: “The overall aims of where we are right now are what we call ‘envelope expansion’; we want to see that the aeroplane aerodynamically and all the general systems on board work nominally in the complete envelope. That’s what we’re doing right now; we’re starting off with a limited flight envelope and then expanding.”
As well as thousands of hours of computer simulations, the first flight was preceded by exhaustive testing of 39-8. Every system was examined as Einerth explained: “Starting in the spring of 2016, having received the aircraft, we did a lot of ground testing before the first flight. Obviously the first thing to check is the electrical system and then to load up the software to all computers to see they are loaded correctly. Next is the fuel system and filling up the hydraulics and checking they are working nominally. We did a lot of landing gear testing before we flew, retracting and extending the gear. To do that, the jet is mounted on the three jacks normally used for maintenance. We then disconnect certain switches and fool the jet so it believes it is in the air. Having tested electrical, hydraulic and fuel systems and the landing gear, we moved on to the environmental control system. Next came the engine tests that were carried out in our specially designed hangar.”
While the engine was being put through its paces, vital vibration tests were carried out to check the integrity and design of the airframe, to make sure, as Einerth put it: “… we don’t end up with a vibration we didn’t expect! We want to see that the wings are vibrating in a way we anticipated in our data models.”
While all this is going on, separate tests are being conducted in simulators, using exactly the same hardware/software combinations. Einerth said: “We don’t use a complete hydraulic system, for example, but we have the actual flight control computer, the mission control computer and stuff like that. It’s just like the real aircraft.”
Of course, the purpose of all this testing is to make sure that when a pilot straps on the jet for the first time and takes off he or she is confident about what is going to happen and how the aircraft will behave. Einerth said that the profile for the test flight was rehearsed in a JAS 39C before the first flight to remove even the slightest risk. Everyone involved in the effort, ground handlers, air traffic control, chase pilots and those monitoring the flight from the control room, knew their roles and what to expect.
The flying programme is divided into different phases, identified alphabetically by the aircraft performing them. At the moment only Gripen E 39-8 is involved, though two others are planned to join. This means the phases will be identified using the number of the jet and a letter to show the test – 8A, 8B and so on. The first of these, 8A, was not designed to expand the jet’s envelope, but was a series of functional check flights to verify the aircraft’s basic handling characteristics. This phase comprised six or seven flights – it’s difficult to say exactly, because some missions involve take-off, landing, hot refuelling and relaunch. Because the programme is in its infancy – at the time of writing the aircraft has only been flying four months and one of those took in the Swedish summer holiday period – Saab is now about eight flights into phase 8B. This second phase is designed to expand the flight envelope in relation to speed and altitude, exploring different g forces and angles-of-attack and angle-of-side-slip. Einerth stresses that the very complex test matrix is designed to examine carefully every aspect of the aircraft’s designed flight profile.
While all this is going on, 39-7 is being used to test the aircraft’s tactical systems, IRST and AESA radar.
And so it will continue, Einerth says, little by little, phase by phase with the flight test programme gathering momentum as more aircraft join the trials. He is very pleased with progress so far, from first flight onwards. As to the future, 8C will explore the flight envelope with the jet carrying various external stores loadouts and at the same time 8D will run the first weapons tests.
Einerth believes the results of the tests conducted so far vindicate Saab’s decision to reuse hardware from Gripen C/D and he is particularly pleased with the jet’s software, saying: “We have had no problems with the software! We did a very thorough job before first flight and that has surely paid off, it’s very stable.” Obviously there have been some glitches that have led to modifications to both soft and hardware, but they have been few and far between and easily remedied.
AIR International asked if the advertised 20% of extra thrust generated by the GE F414G engine results in a noticeable improvement in performance, given that the new jet weighs 2,500kg (5,511lb) more than its predecessor and is slightly bigger. Einerth says that the effects of the extra thrust are very noticeable from his perspective flying chase in a Gripen C, but he is particularly impressed with the E’s fuel capacity: “We have much more endurance with the E than the chase aircraft, so we have to fit them with a lot of fuel tanks to match the test aircraft.” He wouldn’t be drawn on how much more endurance the E has over the earlier Gripen, preferring to say that the new jet would typically carry one external fuel tank, leaving more pylons for stores – and it already has more weapons stations than the C.
Smart fighter
Someone has coined the phrase ‘Smart Fighter’ to describe the new Gripen and the name fits nicely. Although a very impressive aircraft, like its competitors it is nothing without its avionics. Those same avionics are what typically cause most problems with modern aircraft, both in development and in service and it is in this realm that Saab believes it scores big. Gripen E has been designed from the outset to be, like your home computer, easily updated. The design of the jet’s computer systems has been compartmentalised so that a series of code can be updated without affecting the functionality of other systems. Whole subsystems can be modified in the same way and commercial, off-theshelf components can be added without time consuming (and expensive) testing to validate their compatibility with the jet. Think of adding an app to your smartphone. It doesn’t need to affect the internal operating system of a device, because both systems are designed to work with or without each other. Saab knows which bombs, rockets, missiles, sensors and other stores are likely to be carried by its aircraft so ‘all’ it has to do is design the software to interact with that store. It’s very nearly plug-and-play. This design philosophy has another benefit by making the Gripen E future proof. Improvements to the aircraft’s core computers, those affecting the Leonardo ES-05 AESA radar or Skyward-G IRST sensor can easily be applied, as technology advances without altering the aircraft’s mainframe.
Einerth describes the advantages: “What I would say about Gripen E is that it does everything a modern jet fighter should, but it also has this extremely advanced avionics system we can guarantee will stay modern for many years to come. It’s very easy to make improvements when necessary. It has all the performance you need but it also has the most advanced electronic systems, foremost of which will be the electronic warfare system, which will be the best in the world. This is very important for the Swedish Air Force which wants the best.”
In September, Saab announced it has increased its world-wide projected sales figures for all marks of Gripen over the next 15 years by a factor of two to around 450. With Gripen E coming in a little cheaper than Rafale and Eurofighter and a lot cheaper than F-35 those estimates could be conservative.
