Pioneer

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Is there anywhere in this fine forum which gives more indepth information into the proposed Saab 37E and Saab 37X variants of the Viggen?

The Saab 37E was proposed as a Lockheed F-104 replacement for European NATO airforces in 1975;
While the Saab 37X was proposed to Norway in 1967–68.


Ive conducted a search on this means, without resualt

Regards
Pioneer
 
I don't have a great source for Viggen, but according to Robert F Dorr in Modern Combat Aircraft 21 - Saab Viggen, the 37X was a late 60s export version of the JA37 proposed to the UK and Norway (and others). HSA tried to sell the Harrier as a high-low mix with Viggen, but it went nowhere. A British engine was considered for the UK (Olympus?)

37E Eurofighter was a 1970s version of the JA-37 for the "sale of the century".

Both appear to have been minimum change versions.
 
Tada :) This is from the Swedish book System 37 Viggen

Royal Air Force and the Viggen

Original text by Ulf Edlund

If someone in the early 1960s had said that the Viggen would be of interest for the Royal Air Force, that person would probably have been ridiculed. However, the circumstances meant that different Viggen versions were actually of interest at one point.

In 1967 the situation was precarious in Britain. The highly advanced TSR.2 attack aircraft had been cancelled in 1965 and a replacement was needed. A planned order of a total of 400 F-4K / M Phantom II for the Royal Air Force and Royal Navy was reduced to 170 aircraft due to excessive development costs. Instead of purchasing existing versions of the F-4, the RAF wanted to install Rolls Royce Spey engines that on paper offered improved performance. The result, however, was that the modifications needed were much more extensive than planned and unfortunately also resulted in reduced performance. The total budget could not be exceeded, and a recalculation showed that the cost of the 170 aircraft was three times higher than purchasing already developed versions!

The plans to develop a new advanced attack aircraft, AFVG (Anglo-French-Variable-Geometry), along with France had also failed. The politicians favored the Franco-British cooperation projects, and the idea was that the two countries would jointly develop AFVG, the smaller Jaguar attack aircraft, and not at least the civilian supersonic Concorde aircraft. It was thought that Britain would lead the development of AFVG, but not surprisingly, this was disliked by Dassault, which on its own secretly developed its own VG aircraft, the Mirage G. This put an end to the AFVG work. An order had also been placed on 50 US F-111 aircraft but the project was plagued by major development problems and was considered risky.

Could a custom version of the Viggen perhaps be a solution? A requirement specification was sent to Sweden, but it was easy to see that it did not fit the AJ 37, the prototype of which had just made its maiden flight. Among other things, a twin engine and a two man crew were required. The range requirement was also very high. The specification was almost identical to the AFVG's and reflected British superpower ambitions at the time. Twin engine and two man crew were a consequence of the desired range. There were no requirements directly relating to weapon delivery. It was also implied that the requirements could be revised.

Viggen alternatives
In just a few weeks, Saab quickly projected three (!) potential Viggen versions for the RAF which were presented at a meeting in London on August 18, 1967. The negotiations took place on a high level and it was stressed that only people with "a strict need to know" were to be involved. From Sweden, Lars Brising and Gunnar Lindqvist participated from KFF (Swedish Air Force Materiel Administration), with Tore Gullstrand and Olle Esping from Saab. On the British side, more than 20 representatives from the Defense Department participated, with two generals in the lead.

The three versions were:

37XE-1: Single-engine with a further developed RR Spey, RB 168-62R, and increased fuel capacity, otherwise virtually unchanged from the regular AJ 37.

37XE-2: Single-engine with Bristol Olympus B.Ol. 22R, extended airframe and increased fuel capacity.

37XE-3: Two-engine with RB 193, a proposed new engine from Rolls Royce, extended airframe and significantly increased internal fuel.

Only the 37XE-3 corresponded reasonably well to the requirements presented.

According to Brising, who wrote a detailed travel report, the discussion was intense. There hadn't been enough time to make any cost estimates for the meeting, but Brising suggested some numbers, albeit with many reservations. It was obvious that the military leadership wanted to continue with a one-sided development of the AFVG and for psychological reasons didn't intend to change this. American options were already available, and aside from working with Sweden, West Germany was also an option and possibly Italy as well.

(Brising had visited Germany earlier this year and had the impression that the conditions for British-German development were not particularly favorable).
The British side was interested in continuing discussions and the next step was a visit to Sweden at the end of September, where the estimated costs were presented. It was admittedly only realistic to assume that the aircrafts would be license produced in Britain, but as a reference, the following cost per aircraft was estimated based on a hypothetical production of 200 aircraft in Sweden:

37XE-1: 7.5 million. SEK
37XE-2: 9.5 million. SEK
37XE-3: 11.5 million. SEK

The cost per aircraft included the additional type cost for the different versions. To get a complete aircraft, the avionic cost of 2.2 million SEK was added as well as the engine costs. If the regular AJ 37 had been sufficient, the production cost for a series of 200 extra aircraft would have been 6.5 million SEK per aircraft, excluding avionics and engine. 37EX-2 and -3 could in practice be regarded as new aircraft, as is apparent from the figures in the table comparison. The stated values for the AJ 37 reflect the state of the aircraft in 1967 and some changes were made before the series production started in 1971. It is noteworthy that the 37XE-1 (RB 168 ) and 37XE-2 (B.R. 22R) engines were the engines that sat in the two original Viggen "finalists" in 1961, projects 1508A2 and 1562 respectively. All that was needed was to dust off the existing studies! To improve speed performance at high altitude, 37XE-2 and -3 were provided with modified intakes. The 37EX-3 in particular had become an exceptional aircraft and was internally referred to as the "Double Barrel" at Saab. It is easy to understand why when you see the sketches. As the range was perhaps the most critical parameter, the ability to carry four external fuel tanks for ferry flights was added. There is no documentation of the response to the September presentation but it's reasonable to assume that the engine issue contributed to the interest cooling down. The 37XE-1 with a Spey engine required further development and would have worse performance than the regular AJ 37. The 37XE-2, with an Olympus engine which development was stopped in 1965 when the TSR.2 was cancelled, and the 37XE-3, with a brand new engine, was of course not attractive projects to bet on either.

New attempt
The next export attempt was made in 1968. The British had canceled their 50 F-111, which had been ordered the previous year, but considered joining the international working group formed to study and define a successor to the F-104G. West Germany, Belgium, Italy, the Netherlands and Canada had started to work at developing a single seat attack aircraft. The project eventually became the two seat MRCA Tornado.

Without access to a detailed British requirement specification, two new versions of the Viggen were specified that were similar to the then intended execution of the JA 37 (the fighter/interceptor version). These aircraft had compared to AJ 37 a sharper radome, oblique shock intakes and other changes to improve supersonic performance. At this point various more or less fixed cannon installations had been studied and 37XE was offered with a 20 mm Vulcan cannon. The idea was to install the cannon instead of the normal C7 hardpoint and to have the ammunition, 1 000 cartridges, in a new type of the external fuel tank. In addition to the ammunition magazine, you could have fuel or reconnaissance equipment in the tank.

Two engine designs were studied. In conjunction with the JA 37 studies, which had now started, an improved version of the RM 8 together with another variant of it, the RM 8-1, were studied as an option for the 37XE. The other option was more interesting, the planned engine was a proposed development of the Bristol Pegasus, the engine used by the Harrier. On paper the engine, designated B.P.30R, was very interesting: it was significantly more powerful than the RM 8, had lower fuel consumption and was even lighter. And since it was specifically projected for the Viggen it would also have been possible to install it without major changes to the airframe. The preliminary cost estimates showed that it would cost 80 million. SEK to develop the variant with the RM 8-1 and an additional 40 million for the B.P.30R variant. But before the new versions could be presented to the British they decided to join the MRCA project and ended it there.

Data for the "British" Viggen versions compared with the values for the AJ 37 in 1967.

Here are the versions presented to the RAF in August 1967. Three very different aircraft!

This drawing of the FPL 37XE-3 perhaps explains why the version was called the "Double Barrel".

The 37XE was primarily intended as an attack aircraft and it was therefore important to present flexibility in weapon configurations.

The proposed installation of a Vulcan cannon and its ammunition in the external fuel tank can only be regarded as original.
 

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This all appeared in the Air-Britain quarterly I subscribe to, Spring or Summer issue 2016. Can't remember who the author was (I'll dig out my magazines and check) but he found it at Kew and published the article with Air-Britain.

EDIT: Summer 2016 edition of Aeromilitaria, article written by Tony Buttler. Initially the report was found in the Rolls Royce Heritage Trust files at Filton by Clive Richards who passed it on to Tony shortly afterwards. Additional notes were found later at Kew.
 
Beat me to it!

Tony wrote this up for Aeromiltaria when I was editor, but can't recall the issue. I can have a look when I get home.

Chris
 
Outstanding and many thanks folks!
Very very interesting!!
Never knew about the British intetest in the Viggen - period!! :eek:


Regards
Pioneer
 
Sorry Overscan, but sadly the link you posted
Here's a link to the whole book: http://www.flyghistoria.org/images/publications/FR/_37-bok.pdf
, comes up as no good mate!! :'(

Regards
Pioneer
 
PaulMM (Overscan) said:
Here's a link to the whole book: http://www.flyghistoria.org/images/publications/FR/_37-bok.pdf

Thanks for sharing!
Despite the book is on Swedish, even the photos and drawing allows to see long and complex way of SAAB 37 development. Looks like due to this fighter, SAAB saved and enhanced their competences in the filed of combat jets, and now, with Grippen, remains a significant (not big, of course) player on international market.

Could you be so kind to tell, if there were similar publications about other aircraft on the flyghistoria.org?
Unfortunately, I couldn't find it myself.
 
All things come to those who wait - but sometimes they just get dropped in your lap when you didn't even know they existed.

Big thanks.
 
Why were all the Viggens brutally retired by 2006 ? some Drakkens were kept for a very, very long time, up to 1997 at the F10 (from memory). Was the Viggen expensive to fly, far more than the Grippen ? :(
 
PaulMM (Overscan) said:
Here's a rather cool video of the origins of the Viggen - lots of concept models and drawings. Swedish language unfortunately.

https://www.aef.se/Filmer/SAAB_37_Viggen.wmv

Also on youtube:

https://www.youtube.com/watch?v=xFGW3pUxpQY

Amazing find my dear Paul.
 

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Photo number five looks like a delta winged Harrier GR-1, any idea as to what the engine would have been? Pegasus? Certainly looks like it especially with the four poster nozzles.
 
Is 1300-19 rocket powered? There are no intakes and the engines dont look right for jets.
 
sienar said:
Is 1300-19 rocket powered? There are no intakes and the engines dont look right for jets.

Seems likely. X-planes has this in the Saab project list (http://www.x-plane.org/home/urf/aviation/text/saabcanc/saab-projects.html)

1300 (1952): fighter and attack projects
1319 missile armed fighter with two de Havilland rocket engines,

Easy to go from 1300-19 to 1319.

Edit: also on this site. https://www.secretprojects.co.uk/forum/index.php/topic,683.msg5185.html#msg5185

Some of these pics might fit better in the other thread.
 

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Thanks for the intresting video Blackkite, would you know if the video shows a ram air turbine (rat) deployed on the left underside after the viggen reverses on the runway just before we see the engine afterburner light up?
 
I've read the RAT deploys whenever the gear is down. You can see it as it lands, and on the head on shot (about :29, though the camera is shaky) as it turns after landing. It's just in front of the port wing root.
 
I've read the RAT deploys whenever the gear is down. You can see it as it lands, and on the head on shot (about :29, though the camera is shaky) as it turns after landing. It's just in front of the port wing root.
Thanks Del. I thought in most aircraft the rat is only deployed in an emergency. I wonder why it deploys every time the gear is down?
 
Gear down is usually low altitude, low speed. So I assume it was a safety margin decision. Not sure why Saab thought it necessary.
 
@Richard N I was asked to remove the copy of this book I uploaded to the SPF forum server, so it seems like they don't want it distributed.
Paul,

When the original link you put in post #4 gave me a 404 File not found, I Googled 4 clicks and found the one I posted. If you think you should remove my post, please feel free to do it.

Richard
 
Thanks for the intresting video Blackkite, would you know if the video shows a ram air turbine (rat) deployed on the left underside after the viggen reverses on the runway just before we see the engine afterburner light up?
Thanks a lot for interesring information. Of course I don't know.
 

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So Wikipedia mentions with the viggen that the plan was to buy over 800 before the 70's resstion hit leading to a reduced buy, but the link is dead so, anybody have more info on that?
 
Damn. 800 Viggens ? hell of an impressive number. Just for the sake of comparison, France Armée de l'Air standard Cold War number for its fast jet force was 450 - that was the number of Mirage III procured, and also (give or take) the mixed F1 / Jaguar force procurement numbers (200 Jaguars and 250 F1s).
 
Things are just not what they used to be. Lower defense budgets relative to GDP. Higher maintenance hours/flight hour. Lower real competition in the procurement and defense space so entities can command higher prices too
 
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Also remember that this was written/planned before the 1973 Oil Crisis which hit Sweden hard.
 
So I just found what the exact number of viggens were planned, 831 thanks to this RAND study in case anyone was curious.
Facing the future
The Swedish airforce 1990-2005
By Richard A. Bitzinger
 
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Tada :) This is from the Swedish book System 37 Viggen

New attempt
The next export attempt was made in 1968. The British had canceled their 50 F-111, which had been ordered the previous year, but considered joining the international working group formed to study and define a successor to the F-104G. West Germany, Belgium, Italy, the Netherlands and Canada had started to work at developing a single seat attack aircraft. The project eventually became the two seat MRCA Tornado.

Without access to a detailed British requirement specification, two new versions of the Viggen were specified that were similar to the then intended execution of the JA 37 (the fighter/interceptor version). These aircraft had compared to AJ 37 a sharper radome, oblique shock intakes and other changes to improve supersonic performance. At this point various more or less fixed cannon installations had been studied and 37XE was offered with a 20 mm Vulcan cannon. The idea was to install the cannon instead of the normal C7 hardpoint and to have the ammunition, 1 000 cartridges, in a new type of the external fuel tank. In addition to the ammunition magazine, you could have fuel or reconnaissance equipment in the tank.

Two engine designs were studied. In conjunction with the JA 37 studies, which had now started, an improved version of the RM 8 together with another variant of it, the RM 8-1, were studied as an option for the 37XE. The other option was more interesting, the planned engine was a proposed development of the Bristol Pegasus, the engine used by the Harrier. On paper the engine, designated B.P.30R, was very interesting: it was significantly more powerful than the RM 8, had lower fuel consumption and was even lighter. And since it was specifically projected for the Viggen it would also have been possible to install it without major changes to the airframe. The preliminary cost estimates showed that it would cost 80 million. SEK to develop the variant with the RM 8-1 and an additional 40 million for the B.P.30R variant. But before the new versions could be presented to the British they decided to join the MRCA project and ended it there.

Data for the "British" Viggen versions compared with the values for the AJ 37 in 1967.

Here are the versions presented to the RAF in August 1967. Three very different aircraft!

This drawing of the FPL 37XE-3 perhaps explains why the version was called the "Double Barrel".

The 37XE was primarily intended as an attack aircraft and it was therefore important to present flexibility in weapon configurations.

The proposed installation of a Vulcan cannon and its ammunition in the external fuel tank can only be regarded as original.

The proposed Pegasus powered variant of the Viggen sounds really interesting. Are there any sources that have additional information about it (especially projected specifications)? Given that it was considered to fill the role that would have been filled by the cancelled F-111 buy and what eventually became the Tornado did it have any increase in fuel capacity?
 
Some interesting info here:


Such as:

aircraft 37 TK 1 (type configuration 1) as it looked on 6 June 1962 - note the twin seat arrangement:

img_107-4.jpg
 

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