A Visit to the Griffin’s Nest – The Plane

The JAS 39E Gripen is one of the foremost candidates for replacing the F/A-18C Hornet in the Finnish Air Force under the HX-program. As such, I was naturally interested when I was approached by Saab about joining in on a visit by Finnish media to the Gripen production line in Linköping.

Interestingly enough, this is not the first time Gripen is offered to Finland. Back in the early 90’s, the original 39A (and corresponding two-seater 39B) was offered as a replacement for Finland’s aging fleet of MiG-21Bis and J35 Draken, another product out of Saab’s Linköping-factory. It eventually lost out to the Hornet, for a number of different reasons. Will it be second time lucky for “The Smart Fighter”?

Since then, the Gripen has passed through a number of iterations, including the major change from the ‘Swedish’ 39A/B, via the internationalised 39C/D version, to the brand new 39E/F set to fly later this year. It is this version, and only this version, that will be offered to Finland. Despite the Finnish Air Force opening up for alternatives such as more than one fighter being offered, Saab confirmed that they will not offer the C/D, or a mixed package of 39C’s and E’s, despite planning to keep the production line for the older version up in parallel with the newer one past 2020. This is due to a number of reasons, mainly the threats the HX would be expected to face in case of a conflict (i.e. late-versions of the Su-27/30/35-family and the T-50), as well as the Finnish range requirements.

39E underside.JPG
The 39E Gripen mock-up ‘002’ showing the broadened lower fuselage allowing for the carriage of three METEOR long-range air-to-air missiles and a targeting pod. Source: author

The 39E is in many ways a brand new fighter, despite sharing an outward similarity to the older versions. The main landing gear have been moved outwards, making room for a considerably more internal fuel and extra weapon stations in a broader lower fuselage. The upper part of the fuselage has a smoother transition between the fuselage and the wing root, which is now structurally a part of the main fuselage element, unlike earlier versions where the whole wing was bolted onto the fuselage.

However, the core of the new aircraft is in the sensors and electronics. The heart of the combat systems is a brand new active-electronically scanned (AESA) radar called Raven ES-05 with a ‘swashplate’, a fancy name for a tilting device that makes it possible to get better coverage at greater offset angles by turning the radar antenna towards the target. This represents the cutting edge in radar technology, and information from the radar is fused with data from other sensors onboard the aircraft, as well as information received over the data link from friendly aircraft and ground/surface units. The information is then presented on a new wide-angle display as a single pre-processed picture of who else is moving about in the neighbourhood. This is in stark contrast to the current way of having to constantly cross-reference different sensors on smaller multi-function displays to maintain the ‘fused picture’ in ones head.

All of this is powered by the General-Electric F414-GE-39E, a larger and stronger derivative of the F404 that powers the Hornet and, in the form of the RM12, the legacy Gripen. Compared to the RM12, the F414 provides roughly 20% higher max thrust, meaning that the new version should have the extra power needed to handle the additional avionics and sensors, as well as to keep the aircraft as nimble as it predecessor in spite of the significant increase in max take-off weight.

The Dash Seven carrying a mixed load of air-to-air missiles and laser-guided bombs. Source: Stefan Kalm/Copyright Saab AB

An interesting thing is that the Gripen NG Demo, a modified 39D used as a technology demonstrator for the upcoming 39E, has demonstrated not only the new avionics, but the new lower fuselage, landing gear, and engine as well. This aircraft, named ‘Dash Seven’, first flew back in 2008, and has played a key role in the test program for the 39E. This should considerably lower the technological risk, especially as Saab already has managed to break the cost curve and deliver the JAS 39A/B at a lower life-cycle cost than the earlier Fpl 37 Viggen, with the 39C/D version being better still.

All of this is nice and well, but there is no avoiding the elephant in the room: stealth. Gripen is not designed to be stealthy. Though it features some signature reducing measures, such as a “good paintwork” with radar absorbing characteristics in undisclosed areas of the aircraft (presumably e.g. the wing leading edges), this is in contrast to the Lockheed-Martin F-35.

As discussed earlier here on the blog, stealth is not an on-off issue, but rather a reduction in the radar cross section (and other fields, such as heat signature). If this reduction is good, the radar echo of the aircraft will be small enough that it will be able to ‘see’ (and fire upon) its enemy long before being seen. When working as intended, it makes it possible for a stealthy aircraft to fight with impunity against other fighters who are unable to see it. However, reality is seldom this simple.

The IRST mock-up on ‘002’. Source: author

To begin with, there have been huge advances in the field of infra-red search and track systems (IRST), and the Gripen will be fitted with the Selex SkyWard-G. While stealth fighters usually have some measure of heat-signature reduction, it is usually much harder to pull off than RCS-reduction, as the friction of the air resistance on the aircraft skin causes heat to build up.

The other issue for a stealth fighter is the need to find its own targets. If it uses its own radar for this, the radar emission from it can be detected at longer ranges than it can provide a readable echo, meaning that, although its adversaries can’t get a radar lock to confirm the exact location of the enemy, they will know that it is out there, as well as getting the general direction it is to be found in. The alternatives are either using an IRST, which levels the playing field, or relying on information from other aircrafts (or ground units) sent via data link.

The strategy Saab has in place for the Gripen is that a combination of better sensors, and sensor fusing, a top-notch data link allowing the aircraft to operate in ‘silent’ mode a larger part of time, a brand new integrated electronic warfare/self-defence suite, as well as the lower cost and lack of numerous trade-offs required from a stealth fighter will make the aircraft viable throughout the lifespan of the HX. This strategy seems viable on paper, but the simple truth is that we do not have a clear idea of how the introduction of stealth fighters will affect air combat beyond 2030. However, the first study performed by the Finnish Air Force as part of the HX program seems to lend some credit to the idea. The main report is secret, but the public abstract provided notes that stealth features are usually optimised for a set radar band, and that new technology, such as MIMO-radars (basically many radars that are linked together to look at a single target) as well as radars operating at diverse amplitudes, could degrade the benefit of stealth.

Regarding the visit to Saab Linköping, I was invited for a one day event centred on the 39E/F Gripen (arriving the evening before) organised for Finnish media, and Saab kindly offered to cover the travel costs. As was made clear already before the trip, the company has put no restrictions or requests regarding what I do with the information given, nor have they reviewed (or asked for permission to review) any of my texts before publication. Instead, the company representatives were very forthcoming with providing us with information and answering questions we had regarding the Gripen or any other of Saab’s projects. Photography was naturally restricted to certain locations and angles.

One thought on “A Visit to the Griffin’s Nest – The Plane

  1. FkDahl

    The technology behind MIMO radar is rapidly becoming cheaper, driven by chip advances part GaN but also part automotive radar (60-77GHz) and next gen telecom that will feature MIMO in the 2-30 GHz band.

Comments are closed.