Posts in Category: Source documents

Saab AJ and AJS 37 Viggen flight manuals (SFI)

This post is obviously completely unrelated to tanks and might actually be better under the Reference documents tab, but occasionally weird Swedish cold war byproducts come out of my archival research.

In the Swedish Air Force, a the flight manuals were historically called things like Fpl AJS 37: speciell förarinstruktion (“Aircraft AJS 37: special pilot’s instructions”, where “special” is used in the sense that these instructions are particular to this aircraft type), where speciell förarinstruktion was abbreviated SFI. There was usually one unclassified part and 2-3 classified ones. In the last year, the national military archives have kindly declassified most of these manuals for the strike version of the Saab 37 Viggen, the AJ 37 and its 90’s updated version, AJS 37. I’ve turned these into PDF files for your convenience. They are all in Swedish, of course – since the Viggen was never exported, they were never translated.

Fpl AJS 37 speciell förarinstruktion (SFI) del 1 (M7780-402291) (59 MB, PDF format)
Published by FMV:FLYG in November 1994. Open, unclassified. Contains a general technical description of the aircraft and most of its onboard systems without going into too many details on sensitive points.

Fpl AJS 37 speciell förarinstruktion (SFI) del 2 (M7780-402292) (21 MB, PDF format)
Published by FMV:FLYG in November 1994. Formerly classified secret, declassified on July 19th, 2016. Contains checklists and operating instructions, a list of pre-programmed airfields and navigation waypoints, some performance charts and (peacetime) operational restrictions.

Fpl AJS 37 speciell förar instruktion del 3 (M7780-402293) (52 MB, PDF format)
Published by FMV:FLYG in November 1994. Formerly classified secret, declassified in August-September 2016. Contains technical overviews and descriptions of sensitive onboard systems such as weapons, radar etc, as well as an overview of some typical mission profiles. Chapter 5 – which contains information ECM and RWR systems – has not been declassified and only the index page is included in the PDF.

Fpl AJ 37 speciell förarinstruktion (SFI) del 2 (M7780-400172) (58 MB, PDF format)
Published by FMV:FLYG in February 1975. Formerly classified secret, declassified on January 20th, 2016. Contains technical descriptions of sensitive onboard systems such as weapons, radar, countermeasures etc, as well as a description of some typical mission profiles. According to the index it should also contain five more chapters, but these were missing in the binder in the national archives. However, those same chapters are in the Fpl AJS 37 SFI above – albeit for a slightly updated version of the same aircraft.

Fpl AJ 37 speciell förarinstruktion (SFI) komplement del 3 (M7780-400173) (10 MB, PDF format)
Published by FMV:FLYG in July 1979. Formerly classified secret, declassified on January 21st, 2016. Contains aerodynamic performance charts of various kinds – acceleration, rate of climb, combat range, etc etc. The chapter on turn performance is missing.

Update 2016-09-19: added SFI AJS 37 del 3.

Ballistic tests with HEAT rounds against chain armor

A test report from 1971, documenting test firings with two different HEAT rounds against a stand-off “armor” screen made out of steel chains. The target looked like this:

target

From left to right, chain links, one meter of air, 110 mm armor plate, then eight layers of 25 mm “commercial iron” plates (probably equivalent to mild steel). The chain links were 113 mm long and 62 mm wide with a diameter of 19 mm. The chains were spaced at 100 mm intervals.

A summary of the report states that on average, for 9 cm HEAT rounds (pansarvärnspjäs 1110), the penetration was about 40% of what it should be at the same standoff distance, while for 8,4 cm HEAT rounds (8,4 cm granatgevär m/48, aka “Carl Gustav”) the penetration was about 75% of the expected.

A translation of the results follows below; for images see read the PDF version (in Swedish).

Archive reference: SE/KrA/0092/A/A2/001:H/F1-1971/50

Leichttraktor manual

Recently at the national archives, I was poking around a few huge boxes of unsorted tank and armored car photographs from the 1920’s and 1930’s and made an unexpected discovery. In one of the boxes was a folder with sales photos for various foreign tanks from the late 20’s/early 30’s (Renault NC 27, Fiat 3000 and one or two others), and at the back of the folder was a complete instruction manual (in German) for the Leichttraktor, including a number of photographs of both exterior and interior.

The Swedish army was shopping around for new tanks around 1930, and while they ended up with the Landsverk L-10 and L-30 (strv m/31 and strv fm/31), one of the offers that was considered was for Bofors to license build the Leichttraktor, and that’s most likely the reason why the manual ended up in the Swedish archives.

You can read the manual in PDF form here. At the very end is a few instruction booklets for various sub-parts (fuel distribution system, brakes etc). I’ve only photographed the covers of those; let me know if you desperately need them.

Report from terrain trials with T-80U

In late 1993, following the de-escalation after the end of the Cold War, the Swedish army borrowed two Russian T-80U’s and subjected them to a number of trials. Unfortunately, they arrived too late to compete directly with the M1A1, Leclerc and Leopard 2, which had been tested earlier as a part of the procurement of a new MBT for the Swedish army. In the end, the Leopard 2A5 with some Swedish modifications was chosen and entered service as the Strv 122 – you can read more about the procurement process and trials on Rickard O. Lindström’s excellent page. Most of the test results are still classified, but a friend got a report and some video tapes from the T-80U terrain trials declassified recently. The report originally contained comparison values with the Leopard 2 and the M1A1, but unfortunately those were blacked out by the national archives before they agreed to release the report to the public. Russian secrets are not as secret in this country as American and German secrets are.

The videos from these trials are available on YouTube (note that this report only covers the autumn trials, not the winter ones):
Part 1 (autumn 1993)
Part 2 (winter 1994)

Read the entire report as PDF (34 MB)

Some translated quotes from the report:

Summary

With 26 hp/tonne, the T-80U drives and accelerates very well in general. The difference in engine power between the T-80U and strv 104 (re-engined Centurion, nominal top speed 50km/h) is very noticeable on surfaces with some resistance, such as grassland or plowed fields. The T-80U is generally twice as fast as the strv 104 on these surfaces.

The suspension is good and allows high speeds over terrain without much discomfort for the crew.

Despite the antiquated steering system, with a good driver the tank does well in rough terrain, mostly thanks to its high engine power and good visibility for the driver.

Driving in rough terrain or narrow passages in the dark is considerably more difficult, mostly because the driver’s night vision periscope has a very limited field of view.

The tank has a very low reverse speed, which – among other things – limits its tactical options in prepared fighting positions.

The T-80U also does well with various obstacles such as steep slopes, trenches and road banks. The performance is however limited by the lack of self-cleaning tracks, which makes it tend to lose traction.

Re-positioning between prepared positions

If the re-positioning only involves driving forwards, the T-80U performs on par with modern western tanks. If reversing is involved, the T-80U is slower because of its low reverse speed.

In daylight, both the tank commander and the driver have good visibility forwards. When reversing, the commander has some problems with his visibility backwards since equipment on the turret are in the way.

When reversing in darkness, the tank commander has to turn the turret to the 6 o’clock position in order to get night vision so he can direct the driver.

Driving in difficult terrain

In daylight
T-80U average speed: 19.3 km/h
T-80U fuel consumption 201 liters/10 km
Strv 104 average speed: 14.4 km/h

In darkness
The same track as in the daylight trial was attempted, using the driver’s combined vision port (active IR and image intensifier). The trial was aborted after the tank had driven 300 meters in 60 minutes. Leopard 2 and M1A1 both have night vision devices well suited to this kind of driving.

Summary
When driving in daylight, the T-80U could maintain a relatively high speed. The driver’s visibility, the engine power and the steering system are all good enough for this kind of driving.

Driving in darkness, however, is very problematic. The driver’s field of view is so narrow he cannot see the tank’s corners. Since the turret has to be put in the 6 o’clock position to avoid damage to the gun, the tank commander cannot help him either.

Fuel consumption when driving in this type of terrain is very high.

Vertical obstacles

With the splash guard fasteners removed (20 minutes of work), the tank climbs a 1 meter tall vertical obstacle without any trouble. Without removing them, the tallest climbable obstacle is 0.8 meters.

Steep slopes

The tank does well up to a slope of about 25 degrees. The engine power is sufficient and if the surface is dry the track traction is good.

Top speed

On pavement, forward: 70.3 km/h
On pavement, backward: 11.3 km/h
On a grass field: 49.8 km/h
On a plowed field: 37.7 km/h

Slalom driving

Since every gear on the T-80U has a fixed turn radius, the tank has to be driven on the lowest gear to be able to make the tight turns, and it gets a result on par with the strv 104 despite being capable of much higher speeds.

The driver has some difficulties seeing when he’s past an obstacle; the commander has to direct him.

Time to prepare for fording

Depths up to 1.8 meters: 5 minutes
Depths exceeding 1.8 meters: 30 minutes

It is quick and easy to prepare for shallow fordings (up to 1.8 m).

Report from British strv 103 trials at BAOR, 1973

In the summer of 1973, the British Army on the Rhine (BAOR) evaluated the strv 103B in the field. The crews were ordinary British tank crews from the 2nd Royal Tank Regiment, who were sent to Sweden to train on the 103 for four weeks. Ten tanks were then sent to Germany for several months worth of field trials. This report, authored by the Swedish observers from the Swedish Armored Forces School covers the results – such as they were – of these trials.

In general, the observers consider the results of the evaluation to be highly dubious at best. The trials were conducted in such a haphazard and unscientific manner that the results were considered mostly useless. The observers also devote a lot of space to scathing criticism of the BAOR. I’ve translated some of the more interesting passages below – it’s highly entertaining reader.

By request from a reader, I have provided the report as a PDF in addition to the ordinary image gallery.

The observers on the quality of British tank gunners

At the end of the gunnery training, there were two tests with a gun camera, one against a fixed target and one against a moving one, as per usual Swedish standard. The results were bad. The first time these results may possibly be explained by the gunners not taking the trial seriously, but even after they had evaluated their own results and re-did the test the results were very bad. It is possible that more training could have improved the results somewhat, but the more likely explanation is that a large portion of the British gunners simply weren’t suited to their job as gunners. In some cases, problems with bad eyesight were apparent. It should be noted that British tank personnel is not tested in the same way as Swedish personnel before being assigned as tank gunners.

(pg 15)


Both the methods the tank crews used for engaging targets and their aiming skills were unacceptable and clearly worse than that of the average Swedish crew.

(pg 15)

Swedish tank crews were conscripted. Tank crews were considered a particularly demanding position and the requirements for getting assigned to one were very high.

On crew resource management etc

The number of targets detected was on par with the performance of Swedish crews. However, the time from detection to opening fire was in most cases far longer than can reasonably be expected. In part, this is due to lack of training on the 103, but more importantly it’s also due to the way the British crews work together. The tank commander always have to give orders about everything and the gunner is forbidden from opening fire on his own initiative when he spots a target, unlike in Swedish regulations for tank crews. Just like in the 1968 trials, it has been impossible to convince the Brits to try the Swedish method, which is also employed by the Germans for example. The reason cited by the Brits is that tanks carry so few rounds that the commander cannot risk the gunner opening fire on a non-essential target and that the gunners in general aren’t all that good at neither judging the importance of a target nor at correcting their own fire.

(pg 14)


Nor were the Brits willing to accept the principle that whoever sees a target first fires on it. If the tank commander spots a target, the gunner should still open fire on it. According to Swedish tests, if the commander has to hand the target over to the gunner, the time to open fire is on average two seconds longer than if the gunner opens fire by himself. If questions regarding the target’s exact position are raised, this time increases further, up to 10 seconds or more in many cases. Our proposal to try the Swedish method in parallel with the British was rejected without any reason given.

(pg 14, pg 45)

These limitations in engagement methods severely limited the advantages of the strv 103’s duplicated controls.

On discipline and exercise of command

Exercise of command was relatively tame and commanders rarely supervised anything. The subordinates were left with a lot of freedom to complete rather ill-defined tasks on their own. When it came to looking after their equipment, the personnel was rather sloppy and nonchalant.

(pg 13)

On tactics

(in a discussion on fighting delaying actions) The target marker equipment made this exercise an excellent and very illustrative example of how not to fight this type of action (in both Chieftain and the strv 103).

(pg 85)


We would like to call some attention to the British regulations on deployment width for tank platoons. When deploying for defense, a platoon can be deployed over a width as great as 800 meters! Even during attacks, the width frequently reached 5-600 m. The combat simulation equipment often proved that these regulations are clearly inappropriate. The platoon rarely had any means of concentrating its fire and thus the enemy picked tanks off one by one. The British reasoning is “the enemy advances on a broad front and has many tanks, we are few but must cover the entire width”. The German liaison was horrified by this philosophy and the British conduct!

(pg 45-46)

On performance in major field exercises

The last part of the trials was conducted as a major field exercise. The BLUFOR had Chieftains only, the OPFOR mixed Chieftains and strv 103’s. The OPFOR “won”, but the Swedish observers dismiss the results as “highly questionable”.

The BLUFOR tank units appear very unprofessional. They use unsuitable formations, roads and combat positions. In general, they appear to think they are invulnerable. Tank commanders and loaders stand very far up in their hatches. Drivers have hatches open and drive with their head above the edge.

There is no coordination of attacks between tanks, infantry and artillery. Tanks attack alone into forests. Infantry attacks alone across open fields straight at defending tanks. When attacking, units are not concentrated, neither in space nor in time. Attacks are always conducted in a “trickling” fashion.

Radio traffic is very intensive but there are rarely orders given.

At the OPFOR, unit commanders are often deployed very far behind their units, battle group commanders about 5 km behind and combat team commanders 500-1000 meters behind.

CYCLOPS (the strv 103 squadron) combat positioning during the delaying action was usually pretty good.

All tanks, both Chieftain and strv 103’s, are driven very carelessly. No attention is paid to neither civilian traffic nor property damage. Reports on engine failures have a hard time reaching the maintenance units. Map reading capabilities are overall very bad.

When the exercises ends, 9 out of 10 strv 103’s are fully combat ready.

The experiences from these exercises appear to be highly questionable.

(pg 141-142)


British tank crews always carry a lot of baggage, both combat and non-combat equipment (cooking equipment, food, tents etc), on and/or in their tanks. Unlike our crews, they are completely independent of separate cooking units and baggage trains. This meant that the space available in the strv 103 was far too small for their equipment.

(…)

Very little attention is paid to the fact that the unit is exercising on private property. Driving on public roads is very careless and the exercise area is not marked or delimited. Damage to planted fields is frequent despite good opportunities to choose routes over fields where the harvest has already been taken in. Apparently the property damage costs for a similar exercise in the same area last year were on the order of 10 million SEK (about 62 million SEK today, ~6 million EUR). These damages are paid for by the German authorities. During this year’s exercises, five people died in accidents; during the same exercise last year, thirteen people died.

Strike aircraft are available on request during the exercises. Helicopters are used for both recon and command duties. The routines for coordinating with airplanes and helicopters seem to be well developed. The British command APC is well suited to its purpose and the space available is better than in our equivalent vehicle. Wired communications are not used between brigade staffs and battle groups. The system with call signs painted on the rear of the tanks appears to work well.

(…)

Deployment width and depth is considerable in the smaller units. Tank platoons are often deployed over a width/depth of 600-800 meters. (…) Tank platoons are frequently deployed independently behind each other. Support is organized within the platoon and not between platoons. The rear platoon is usually 500-1000 meters behind the front one. Hence, the result is that the enemy knocks them out one by one, platoon after platoon. Both platoon commanders and tank commanders act very independently and choose both their own routes and positions and their own timings for advancing or repositioning. The whole thing frequently resembles a guerrilla war or every man for himself.

The infantry is used way too late to take terrain from which the enemy can fight the tanks up close with weapons such as recoilless rifles. The tanks attack first. When they start taking fire, the mechanized infantry is deployed. There is no planning for attacks in depth. On the first day, it took seven hours to advance seven kilometers with the BLUFOR’s combat team (17 tanks and a mechanized infantry platoon) against an OPFOR with 9 tanks and one mechanized infantry platoon, deployed in three lines.

If a platoon or squadron commander’s tank gets engine problems, the commanders do not move to another tank. Tanks are frequently deployed in very unsuitable positions where they are easily knocked out. The observation and recon duties are conducted badly. The soldiers seem very passive. Chieftains are often positioned behind a ridge with the gun and the chassis side against the enemy. The strv 103 crews rarely clean their optics.

When fighting a delaying action, the tanks in a platoon retreat by turns along the whole depth of the deployment. Withdrawal is frequently started far too late, and the tanks are thus knocked out one by one. Despite the terrain allowing opening fire at long distances (2-3 km), fire is often opened far too late (500 m). There is never a rear platoon deployed to cover the front platoon’s withdrawal.

In light of the heavy criticism above, it has been very hard to judge how well the strv 103 has proven itself. The results have mostly been influenced by troop performance and not by the tank’s performance. As far as it has been possible for us to observe, though, we cannot say that the strv 103’s have suffered more losses than the Chieftains.

Strv 103 availability has been good. Most of the time all tanks have been in working condition during the day. On the OPFOR side, the Chieftain availability has dropped steadily. Near the end of the exercise the availability was down to 50%, and thus a Chieftain platoon was transferred from BLUFOR to OPFOR.

(pg 127-128)

On British vehicles

The Chieftain tank:
The reliability seems surprisingly low. During the exercises, the number of tanks that had to drop out due to mechanical trouble was relatively high. Mostly, it’s the engine that is the problem. When a Chieftain stops, after a little while there’s always an oil slick on the ground or garage floor under it. The gun stabilization also fails frequently. The accuracy of the contra-rotating feature in the commander’s observation cupola is very low. It is almost never used by the Brits. The tank’s speed over terrain does not seem to be superior to that of the S-tank. The commander’s observation equipment is very good.

The Scorpion tank:
The Swedish personnel got an excellent briefing on the tank and was also allowed to drive it. It is very fast and easy to drive. The observation equipment is absolutely excellent. (…)

The FV 432 APC:
Appears to have a large number of different reliability problems, mainly concerning the steering gears. The vehicles are so far gone that they are considered a danger to traffic. According to maintenance personnel, a lot of the problems are caused by the soldiers not doing sufficient daily maintenance.

(pg 146)

Read the entire report in PDF form, or hit “Continue reading” to browse the photographed document images on this web page.

Archive reference: SE/KrA/0092/A/A2/001:H/F1-1974/35

Report from British evaluation of the S-tank (1968)

In 1968, the British army borrowed two brand new S-tanks from Sweden and subjected them to six months of various trials in Britain. This report is covers the result of those trials. Since it’s in English, I’m not going to summarize it further – read it yourself and draw your own conclusions. However, keep in mind that the S-tanks tested are very early models that are suffering from some teething problems.

If you want to pick cherries, here are some particularly interesting/entertaining pages to get started on:
page 97 (tank vs SPG discussion, etc)
page 132 (results from automotive trials)
page 142 (crew comments)

The report is also available in PDF form.

Archive reference: SE/KrA/0092/A/A2/005:H/01:H/F1/10

Reports in French on the Swedish trials of the AMX 13

Various reports in French from the Swedish trials of the AMX 13. These are just translations of the corresponding Swedish reports, but I thought they’d be more interesting to French people than to Swedish people, so the French version it is.

Archive reference: SE/KrA/0062/D/01/016:H/F I, various volumes from 1952

Report on protection from fragments from HE ammunition

This is a rare (on this blog) report in English, from the Aberdeen Proving Grounds in Maryland, USA, titled Protection provided by steel and aluminum armor against fragments from high-explosive ammunition (U). To aid potential Googlers in finding it, I’ll list some identifying numbers.
Report No. DPS-67
OMS Code 5510.11.268
D. A. Project No. 548-03-001

The report seems to have ended up in a Swedish archive via official channels; it appears to have been forwarded via the Swedish military attache in Washington DC. Some appendices are missing, presumably removed by the DoD before the report was handed over to foreign hands.

Future development study by the armor committee of 1946

This study (dated 1946-07-02) presents what the armor committee of 1946 thinks future Swedish tank developments should focus on, in light of foreign developments, current technical limitations, requirements and desires from the army headquarters and various other factors. The study is about 50 pages long plus seven appendices, not all of which are present here.

The committee finds that research should focus on:

  • raising the muzzle velocity of current anti-tank guns above 900 m/s
  • improving current AP rounds so that they don’t shatter at impact velocities over 900 m/s, possibly by using a core of a harder material
  • finding a way to make HEAT rounds work at high impact velocities
  • developing an effective protection against HEAT rounds
  • studying the actual damage effects of HEAT rounds

Further, it recommends that development should start on:
A) a tank, preferably no heavier than 25 tons, armed with either a 7,5 cm or a 10,5 cm gun, with a specific engine power of about 20 hp/ton and protected frontally against guns of up to 57 mm caliber at 400 meters.
B) a tank destroyer, no heavier than 30 tons, armed with either 10,5 cm kan m/34 or 10,5 cm lvkan m/42, with a specific engine power of about 17 hp/ton and frontal protection against guns of up to 7,5 cm caliber at 800 meters.

Finally, it also discusses re-use of older tanks, such as rebuilding strv m/41 into a TD with a 7,5 cm gun.

Archive reference: SE/KrA/0062/D/01/025:H/F I/8

TK 105-9 construction program

This letter (dated 1952-09-27) from Bofors to KAFT describes a proposed construction program for a 105 mm L/67 rifled tank gun, fed by two 7-round autoloader drums and placed in a heavily armored turret intended to be mounted in a 35-ton tank currently being under development at KAFT (project EMIL, of course). The letter mentions that 12 and 15 cm L/40 smoothbore guns are also possible alternatives but no further details are provided. There’s a list of blueprints for these guns but they are (as usual) missing from the archives because apparently the bureaucrats at the time hated historians.

Archive reference: SE/KrA/0062/D/01/016:H/F I/28