JA-37 Viggen – a truly remarkable aircraft


1/48 Airfix Saab JA-37 Viggen F 13 “Norrkoping” Wing of the Royal Swedish Air Force, 1981


by Jim Dick


Introduction

The Saab Viggen needs no introduction, being easily recognisable by all students of aviation. But in building this kit and the associated research for the build I was continually impressed by the lateral thinking that had gone into this aircraft’s development by the folks at SAAB. Most of this thinking was directed at giving the Sweden Air Force a supersonic short takeoff and landing (STOL) strike aircraft capable of operating from harden aircraft shelters dispersed around Sweden’s public highway network.

The Viggen is powered by the RM8 Turbofan, a licensed built version of the 1960’s Pratt & Whitney JT8D engine, versions of which powered the DC-9, 727 & 737 commercial airliners. The main difference being the fitting of an afterburner by Volvo Aero. The Viggen is one of only two afterburner equipped aircraft to also feature a reverse thrust system, the other being the Tornado. The RM8 when fitted was the most powerful fighter engine in the world and allows the Viggen to takeoff within 500 metres.

To aid with short field landings, a computer is linked to the pilot’s HUD. This ensures he hits the ground within 30 metres of a designated threshold after a punishing no flared approach with a sink rate of 5 metres a second. The impact is absorbed by the heavily reinforced tandem main undercarriage wheel arrangement with plenty of travel in the undercarriage legs. The compression of the front undercarriage leg automatically activates the reserve thrust system. Pilots liken the experience to an aircraft carrier landing. Once on the ground the reverse thrust system can be used to reverse the aircraft into hardened aircraft shelters without the need for a tractor. The large tail fin can be folded down to a horizontal position to fit under the low ceilings.

The Viggen was built in four versions, the AJ-37 strike fighter version (to replace the Saab A-32A Lansen), the SK-37 two seat trainer, the SF-37 recon version and much later as the JA-37 interceptor fighter version. This last version includes a 30mm cannon linked to a fire control auto pilot system, which controls aircraft pitch and yaw and provides the pilot with bank information via the HUD. Once the pilot locks a target the aircraft effectively fly’s itself to the correct firing position.

Another design requirement was that the Viggen should be serviceable very quickly by conscripts with relatively limited training. Re-fuelling and re-arming by 7 men, of which 6 are conscripts, should take less than 10 min for the JA 37 fighter version and 20 minutes for AJ-37 strike or SF-37 recon versions. It is said that strike squadrons are expected to fly 11 missions per aircraft over a 24-hour period.

When the interceptor version of the Viggen was developed a grey low vis-ability scheme was adopted but some interceptor aircraft were kept in the ground attack splinter camouflage scheme to keep the bad guys guessing. Those tricky Swedes!

Saab JA-37 Viggen – the build

This was a fairly labour intensive build. With all the time spent re-scribing panel lines and getting this build to the painting stage, (over a 3 month period), I was certain that I will not be building another Airfix / ESCI Viggen again in my lifetime.

If I was only ever going to build one Viggen then it would have to be done in the very distinctive splinter camouflage scheme. To help us out here I used the excellent Gator paint masks (http://www.gatorsmask.com/). These come in the form of six A4 size vinyl masks which are magic to work with The entire paint job only taking a long weekend to complete.

To bring the old ESCI/Airfix kit up to a modern standard I used the excellent Neomega cockpit (http://www.neomega-resin.com/) which fitted well except that I had to sand down the front wheel well to get it to fit under the resin cockpit. As it turned out this was a blessing as instead of having to shorten the front undercarriage, (due to the shallower wheel well), I  had to lengthen it a tad to get both main undercarriage wheels to sit flat on the ground.

I couldn’t seem to get the front canopy to sit correctly as it seemed to be a good 2 mm too narrow on both sides of the fuselage. I solved this by gluing it down central and applying loads of Mr Surfacer to fill the gaps on both sides.

The intakes on the Airfix / ESCI Viggen are incorrect. TheViggen has two dog tooth cuts in the lower section which needed to be cut, (check your photo references). The centre line drop tank should have 4 fins in an ‘X’ pattern instead of the 3 fins in a ‘Y’ pattern which was only used on the AJ-37 version. Airfix did not change the old ESCI AJ-37 kit to the newer JA-37 version. The new fin design was changed to allow for clearance once the JA-37’s 30mm cannon which was included.

The decals are by two bobs (http://www.twobobs.net/) and these went down very well over a coat of future.

I used Testors Model Master enamel paints and followed the two bobs colour callouts listed below:

  • #1716 (FS34227) Pale Green (this seemed to fade very quickly to a more brown colour on some older airframes),
  • #1704 (FS30277) Armour Sand
  • #1713 (FS34102) Medium Green
  • #1749 (FS37038) Flat Black (I actually used #2040 Aircraft Interior Black)
  • #1722 (FS35622) Duck Egg Blue (Over sprayed with thinned down Tamiya smoke to dirty it up some).

The Airfix kit only comes with 2 x Aim-9L Sidewinders and 2 x Sky Flash missiles. These are fairly basic so I replaced them with missiles from the Hasegawa weapon set ‘C’ (using Aim-7F Sparrows in place of the Sky Flashes).

I made good use of brass rod inserts to strengthen the major joints in this kit. This involved drilling a series of 0.9mm holes with a pin vice and then using CA to glue 0.8mm brass rode into the hole. This makes for a very strong joint and the model is quite happy being picked up by the forward canards or even the horizontal stabilizer.

In 1/48 scale the Airfix / ESCI Viggen is the only game in town, but be ready for a build that will test your will power to go on. In the end it’s a very rewarding addition to the collection.


Saab JA-37 Viggen – Summary


In 1973 the RAAF investigated the Viggen as a possible Mirage replacement along with the McDonnell Douglas F-15A, Northrop P600 and the Mirage F.1 but recommend that a replacement decision be deferred so maybe a RAAF “What if” colour scheme is an option?

 


 

This site is owned by David Harvey

All material is Copyright © 2003-2016 and may only be reproduced for personal use.
Please contact the Editor for permission to use any material on this site for any purpose other than private use.

Contact: editor@aussiemodeller.com.au