I SUCK AT AIRCRAFT IDENTIFICATION AND GEOGRAPHY: I start the video by annoying a lot of people by calling Finland and Iceland ‘Scandinavia’. Thanks to @CasGRos (AKA Sacgr) for spotting a mistake on the Patreon early access before the video even released here: the aircraft shown at 9:05 is technically not a Lansen. It is a trainer aircraft. Also, the 'AJS-37 cockpit' is actually from a Gripen. 3:37 The canards couldn’t move like that. They were basically landing flaps to enhance the STOL capability. 12:30 Apollo 10 launched in May 1969 is probably more correctly referred to as the first flight of a ‘production’ AGC since it was the first to contain a working version of the Luminary landing program. At 29:20 it sounds like I make an error but I don’t - I just omitted some detail that would have made it clearer. The ‘1.6 failures per year’ also included running time on the ground in addition to the stated 150 flight hours.
Your country developed one of the most effective antipersonnel mines* in history: the LEGO block * effectiveness highest against barefoot and sleepy enemies
I may have missed it, but if anyone is curious CK37 stands for: "Centralkalkylator 37" i.e. literally "central calculator 37." (The '37' from the Viggen air force number for the type)
Saab's ease of use philosophy trickled down into their cars, in their instrument panel layouts and ergonomic. I drive a 9000 and the EDU ( Electronic Display Unit) in the dash is very helpful and very very accurate in showing its range, average fuel consumption and real time fuel consumption, it was incredible for its time in 1986. Also my favorite is its minimally lit green dials and readings, it reduced glare at night, it made me frustrate driving other cars with brightly lit dash, so much glare at night.
Fun video, particularly since I for 14 years worked with one of the CK-37 programmers. Liked the comments regarding their workflow because when we met, he where Saab Autos Chief ICT Strategist, later becoming a key GM Europe strategist. Having been a system ops and governance manager for 10 years, through our discussions and with his logical thinking, often referring to CK-37, made me adopt much of his systemic thinking, which has been of tremendous advantage for over the last 30 years. I met a couple of others from that team, and they also had a strong enterprise systemic thinking, a treat that I still use. In principle, Keep It Simple, Stupid, go to the core, and drop the "fluff". Thanks for the video.
Regarding the YT premie;r the tone shift from that epic sci-fi count down animation with the heart pumping music, to Abba footage is INSANE. One for the books really.
The updated AJ 37, the AJS 37 Viggen had, as the film suggests, a digital map of Sweden stored in its memory. This map however was not displayed to the pilot. There was no map display in the cockpit (The JA 37 had one, but that´s a completely different beast). The map consisted of elevation data, and this data was compared with data from the radar altimeter and the navigation system. Comparing the stored data with the radar data the nav system could correct itself automatically, not relying as much on manual navigation fixes. One thing that strikes me, as having tried the Viggen and various other aircraft in DCS, and even the 39C and E in simulators at Saab, is that the CK 37 is not only very advanced for its time, but also easy to use. For a non-digital pilot the output from the CK was mostly presented in a way that a 1970's pilot was used to. Finding out if you hade all the fuel needed for the mission was as easy as checking the fuel gage. No need to enter a sub page in an MFD or on an UFC or manually entering a BINGO at the start of the mission.
The best anti ship missile of the 1980s was probably the P700 Granit. Fired in salvos of atleast 4 missiles, they approached the target below the radar horizon. One missile would briefly pop up and search for targets with its radar, relaying the targeting information to the rest of the swarm through datalink. The radar and computer of the missile where not only able to detect ships, but to identify them as well, and was able to assign a number of missiles to different targets based on preset priorities. NATO reporting name SS-N-19 Shipwreck. The Soviets were able to make some excellent kit when they put their minds to it.
Wasn't that how the heavier P-500 bazalt worked aswell? Also, as much as the p-500 launchers on the Slava may look weird, you most likely haven't seen the project 1234 ovod (nanuchka), what were they thinking with that
@@AddSomethingCreativeHere Cheap*, fast, expendable*, CIWS-protected means of getting a minimal viable salvo** of AShMs to a target that can also perform other tasks to some degree. *Not really **According to calculations during design phase, actual minimal viable number of missiles ballooned after Aegis & VLS-equipped vessels started entering service
@@theleva7honestly, I think the biggest nightmare now for AShMs is that one central command ship can utilize the SPY radars of every ship in the formation to direct every missile available from the VLS at any vampire that it might want to eliminate from the sky. Provided that it works, of course. Can't exactly imagine the US shooting a bunch of missiles at a CSG* to test it.
I grow up a quarter mile from the Saab factory and airfield in the sixties. And remember when Draken came in for landing, and we where laying in the grass looking up. And then we kids saw the first flights of J37, When made sonic booms my mother always said now the is some important one visiting :-)
@@LostieTrekieTechieafaik Denmark, coz I used to play Eve-o with a couple of Finn's and some Danes who argued about it...for literally days, every times we had down time they would argue
These flight computer videos kick ass. I'm totally stoked for the next one too, at the hint of analog computing. There's some neat old film reels about mechanical naval gun control computers that could do All kinds of integration, differentiation, etc.. with rollers and cogs, racks and pinions..
Thanks! The brief clip of the mechanical components is from one of those film reels. Let’s just say I’m currently in the process of building some of those parts for the next video.
I love this plane so much, it is a true wonder. It is one of the best marriages of task, system, and airframe there has ever existed. The navigation, the system symbology, and the sensors. They're seamless. When you fly an A2G mission in DCS, and see the radar display with the RWR and NAV circle, it's a buttery smooth experience. The cockpit design, the weapons, the airframe, they act in such a way that they allow you to think and fly and deliver. That is a difficult thing to achieve for a2g missions without smart weapons. Especially in the 60s. Having tried this and other planes in DCS, I believe the viggen would be terrifyingly combat effective platform.
@@2KOOLURATOOLGaming The only way I could describe the viggen in DCS is neat. Imagine everything you need to worry about in an A2G striker in the cold war, and most of it automated. Now do it transonic, being faster then the contemporary interceptors. The way navigation turns to targeting to weapons deployment to egres. Its beautifully smooth, and it can handle pop up targets of opportunity too.
@@2KOOLURATOOLGaming They do different roles. The Viggen is useles in DCS AA combat while the Tomcat has very very funny low speed handling (don't be afraid of disabling the flight computer when trying things out) and the as with all Eagle Dynamic missiles the AIM-54 is very poorly modelled so the F-14 lacks some of its bite too.
@@HowIsAsh It is very bad. Last time I played it didn't loft and before that it's acceleration was worse than a Sparrow as well as it losing track to targets flying straight. DCS has some of the worst missile modelling in the business and unless they brick every missile around it wouldn't be a good day for ED.
The Viggen module in DCS is one of my favorites for its chunky buttons and numerical data input. By today's standards the input is crude, but it has a bespoke and practical elegance that cannot be denied. Entering a flight path with preprogrammed attack coordinates is easier than slipping in a NES cartridge and inputting the Konami code. The radar also displays vectors superimposed over the look down radar returns which can be adjusted and calibrated in flight. It is just so much fun to fly in that simulator. If you don't have/can't play/aren't otherwise interested in DCS, I would recommend you find a friendly flight sim nerd in your area and just spend an afternoon pushing its buttons, you won't be disappointed.
Dropping a like isn't enough. I want to thank you for investing the effort to make this video. I enjoyed every pixel. The pre-4004 era is an underappreciated goldmine of computer history and I'm so glad to have a worthy UA-camr covering the topic in depth.
Same engine used by DC-9s and MD-80s widely used by Scandinavian Airlines at the time. (Doesn't have anything to do with the Viggen, but kind of a fun fact imo)
You might be my favorite youtube channel. I always look forward to your uploads, and I rewatch them regularly just because there's so much to absorb and learn from.
The Marviken nuclear powerplant was actually just about finished. It was shut down because the Swedish nuclear weapons program was, so the main plutonium production purpose wasn’t needed anymore. It was a heavy water BWR with questionable safety so it was determined not to use it. An oil boiler was installed instead and the plant was used for reserve power. More regular BWRs was built instead for Swedish power needs.
To elaborate on this, most of the access piping was at the bottom of the reactor vessel which made it vulnerable to shakes and whatnot. A burst pipe would empty the vessel in a hurry and cause a bit of an issue. At the outset this was not considered very significant, but updated safety requirements during the build period lead to the decision to discontinue it. I plan to visit that place next summer.
@@mrkeogh Swedens is very very interesting if you like the more "conspiracy" side of it lol. It was canned in 1972 BUT technically the Gripen can carry tactial nukes and the Bandkanon could also technically fire them despite being a howitzer. There are also very diffrent accounts of it with people that worked on it saying that they never got anywhere and others saying they actually touched a working nuke that was just never detonated. There is a somewhat popular theory here in Sweden when talking about it that "we probably don't have nukes but i wouldn't be suprised if the parts are laying around and we can assemble them in a day if we truly want to". Although it's said more as a joke it could actually be the case
At 9:06, I am pretty sure that the aircraft you called the Lansen is actually the SAAB 105 trainer, based on the thicker nose, the lack of cannons and the position of the air intakes. Otherwise, this is an amazing and really well-explaining video!
YESSSSS let's go!!! The viggen is the plane that got me into dcs, and later on into aerospace engineering in general, all those years ago. The first principles aero research on the configuration is unreal, especially from such a small nation. The nasa paper is a great read. Not to mention the unreal digital computer and hud (wayyy ahead of its time) license built modified engine, etc. Too many things to list :D
Another great video. Big thanks for putting these together. Your presentation is professional and you are clearly very passionate about the subjects which makes these ever more enjoyable to watch.
Ah, good guess! I was thinking perhaps it was the fire control for the A-10, but the analogue part should have eliminated that. I have a lot of admiration for the gunnery system of the B-29, fantastic piece of kit especially once the radar rangers were added and the gunners didn't have to worry about setting range manually.
regarding the matter of mounting the early IC packages on aluminum, with the boards on each side.. I worked with military avionics in the 70's and 80's, and we had to provide heatsinking for simple TTL IC's. That stuff used a fair bit of power, and when you have to operate properly at mil temperatures (125C? I forget...), you do have to work to get that heat out of the avionics. For the earlier logic types, I imagine the power dissipation was even worse.
Yes, having 2 5V power supplies, each capable of 30A, with one being used to power the memory and IO, and the other being pulsed at 400Hz, to power the actual arithmetic systems, because otherwise the computer would melt. Even with that you had 4 120mm fans running if you were operating it on the service bench, just to keep case temperature below 70C. It was a very effective pie warmer, and kept coffee hot as well while running the diagnostics tests. Then open it, and play swap the cards, because they would always have slight timing differences, so you would mix and match. Hard to change an IC on a vapour phase reflowed card, where there are DIP packages on both sides of the board with pins between the other side package.That involved a lot of filing and work to cut the old IC out, leaving the leads, and thin them down to allow the new one to be soldered to the old leads. Most common failure was a 5474, it would reliably be the faulty one in that position.
@@chrismofer Aircraft did it a similar way, using the LOX supply to the pilot as part of the recirculating cooling air, and thus serving both to cool the avionics and also give the pilot breathable oxygen flow at something approaching tolerable. Then for the extra cooling needed they simply used a pure ethanol water blend (around 140 proof) as evaporative cooling to make up the rest. Those drums of coolant were more securely locked up than the munitions were, for some reason.
Both TTL and (especially) ECL draw a fair amount of power even when idle. With the later CMOS (found in virtually all modern devices) current is (essentially) only consumed during switching with only a small quiescent power draw due to leakage. Before CMOS was perfected though the tradeoff was slower and low(er)-power (TTL) vs. fast but power-hungry (ECL).
3:51 it’s worth noting that the canards on the viggen were not actuated as the canards on the EF typhoon, Gripen etc. they were flaps actuated by the gear being extended or not and were the viggens flaps moving more air under the huge double delta
Just one small thing, the fact that the ferrite core memory is so resilient, is not always an advantage, on military hardware, often you don’t want info to fall into the wrong hand’s, even in the case of a crush.
@ indeed, especially considering the additional computational effort involved (this is one of the reasons that systems like the javelin ATGM, use FPGA’s that are literally being reconfigured and reprogrammed from scratch each time they are armed, the GNC algorithm is the most important thing in that case). Great video either way 🙏👑
@@AG-pm3tc The most valuable secret would be the list of secret airstrip locations. Once stolen, they could all be added to strategic target lists for use by nuclear planners, potentially wiping out the entire air force, including ground equipment, personnel and parked aircraft. Fortunately, this could be wiped in a fraction of a second along with the code, provided there was a special way to disable the write protection during self-destruct. Much faster than destroying paper maps in the pilots pocket.
@@johndododoe1411 _"The most valuable secret would be the list of secret airstrip locations."_ My thoughts exactly. That's not the kind of thing you want to keep in non-volatile memory.
@@johndododoe1411 Thinking of it it could be done while still leaving bunch of variables that are meaningless without context (but potentially very useful for determining what went wrong)
I discussed this video with my aging dad who worked on the CK37 on Datasaab and loaded data to it. Personally I worked on the bodies of the last three AJ37s to be delivered to the Airforce, and on JAS 39 Gripen. They are both awesome planes. The reverse jet on Viggen was my favorite, and the Viggen looked awesome before painting them green. Viggen means "the Thunderbolt", but it is also a kind of duck. "Gripen" means "the Grip", which is a cross between a dragon and an eagle. It is the symbol on the Scania semi-trucks, and it was inherited from Vabis lorries.
The Algorithm serves me MUCH retro computer content and this is about the best I've ever seen. The way you cover so much (needs, contemporaries, logical design, physical circuit building, programming methods) all in the one video. Nicely done
One nitpick: A HUD is properly expanded to Head Up Display, as labeled at 20:06 , because we humans only have the one head. A Heads Up Display would be needed for Zaphod Beeblebrox.
Except "Heads up display" sounds more fluid. Grammatically, it still makes sense as the plural indicates the collective of all the users' heads being up, so unless there is only ever one built. Languages, like Japanese, often aren't so distinctive with respect to plurals anyway, as one can explicitly state the number in question if it is important in the context of the statement, which it seldom is.
@ But the manual on-screen at the time point I indicated does not use the plural. And English is not Japanese, nor is Alexander, nor is the Viggen. One place where “heads-up” is absolutely correct is when you’re warning a group of people (i.e. more than one person) that some sort of danger is headed their way, because multiple heads do need to look up. And imprecise rules about grammar have zero business in aviation, engineering, or anything else that involves safety.
Swedish can be a shocking language. Sometimes similar to english, but some words or phrases are WILDLY different, with little reason but historical coincidence.
@@NoOne-ef7yuMy personal favorite is when people from the U.S hears about "automatisk fart kontroll" in the Viggen, which is "automatic speed control" in case someone reads this and doesn't know.
I find that knowing some German helps a lot with being able to read the Nordic languages. There's a lot of overlap in the vocabulary. Fahren, lustig, etc.
BTW, Russian MIGs were using vacuum tubes till 1970-s. I have seen and touched MIGs blocks at a garage sale. Targeting system images were optically mirrored together by prisms. A mechanical gyro was the nicest block.
Nothing wrong working with known good components. I remember back in 2002 when NASA was looking for 286 CPUs for the space shuttle. Or how the James Webb Space Telescope, launched in 2021, uses a RAD750 at 118 MHz, a radiation hardened version of the PowerPC 750, which was also used in the Nintendo Gamecube in 2000 (more precisely a PowerPC 750CXe at 486 MHz) and the 1997-1999 G3 Mac (at up to 400 MHz).
Excellent video! For anyone visiting the north of Sweden, right in front of Luleå AFB, there's a small but interesting museum, operated by enthusiastic volunteers (mainly retired pilots and maintenance crew) who are more than willing to answer your questions about these planes and share their stories about their time in the air force. Keep in mind that it's only open once a week though, so better check with the Luleå tourist office first.
For those who wonder whate the text in the thumbnail says, here's a rough translation: "For many executives at Saab, electronics was in the beginning of the 1960s still a question entirely subordinate to construction and production of aircraft, which naturally was Saabs main diet. Terms like computers and datascience were still newfangled. But for a few key persons in the systems department, the insight into the arrival of computer technology had started to grow. Here at the end of the 1950s and start of the 1960s started a tentative development towards a computerisation, whose enormous development-power few only guessed at, and most had no perception of"
I forgot the thumbnail for the premier is hi-res so i wasnt really ever expecting that text to be readable! It’s just copy-pasted from one of the many source documents i used (that said I did paste something relevant in just in case it would be readable)
41:36 as someone who has this as a module in DCS: my guess is that the "magnetic realign" and "stable platform" are references to the TERCOM system that automatically attempts to correct navigation drift using the radio altimiter and terrain features. this is yet another incredible ahead of its time feature in the viggen
16:50 The Viggen could also its navigation/fire control RADAR to perform update fixes as well-co-locating waypoints with visual landmarks helped in this regard. Also, at some point, the Viggen's navigation software included a coarse terrain-mapping system to further enhance accuracy.
Hear hear from Sweden! Growing up in one of the major regimental towns in northern Sweden it was fun every time the Viggen pilots did a low run over the town at night and hitting the throttle. The car alarms were going off everywhere and we all laughed about it every time! I've had the pleasure of standing very close behind both a Draken and a Viggen as they were taking off. Talk about thunder - and it was also the best way to clear blocked sinuses since I believe the starting fuel contained a lot of liquid oxygen? This was back before they dismantled the armed forces which we are currently desperately trying to rebuild in a hurry... Luckily our arms industry is still rather strong and we still prefer homegrown solutions, although we just joined NATO and thus ended our neutrality and non-alliance. Sadly Gripen isn't as majestic as Viggen, and it doesn't set off the car alarms at night, but we still own our air, sea and land! Thanks for a greatly researched and presented video! I've flown the Viggen simulator once in the 90's which was rather interesting since I'm an engineer who's designing and building large computer systems, and I frankly thought the simulator was rather primitive - but I knew how old it was and that made it almost as impressive as the plane itself! It took many great engineers and visionaries to design and build all those planes and supporting systems. Something we're proud of here! p.s. I failed my one and only landing attempt in said simulator, but it was a spectacular crash since I attempted to land on the main road through the town of Östersund! It's a memory I'll never forget... ;)
An excellent overview of a remarkable machine. If you ever want to update the video, though, reach out to the Digital Combat Simulator community. They have the refitted AJS37 at their disposal and can get some excellent footage.
37:35 I’m amazed that an aircraft built when the Viggen was not only had a flight computer but had one that could record and store enough information to be used almost like a black box during testing of the aircraft.
@@erikgustavssonah, thanks. his use of the word “automatically” had made me think it was an automatic system. I’ve deleted that paragraph from my comment.
@@michaelimbesi2314 You can also -strike out- text by putting a - at the immediate start and end of a word or phrase (they have to abut the first and last letter). [Also * for *bold* and _ for _italic_ text.]
3 decades in tech, engineer, I remember a day when I worked around others that could have created a system that lasted 3 decades. Now, I don’t think it’s possible, in fact, I don’t even think anyone can think in those terms anymore.
Love your videos. The excitement of the intros, the renders and animations, the nerdy details of the tech, the context, the archive footage - all come together to make a great narrative. Also, the use of archive footage, practical demonstrations, and animation (albeit not stick figures) also reminds me of the best TV series of all time, 'The Secret Life of...' by Tim Hunkin and Rex Garrod.
Actually 200kg computer that can replace crew member is a huge win out of the box. Ejection seat, all instruments, structural and body parts to create additional space would most likely add up to much higher weight
As a lover of all kinds of mechanical contrivances and computing machines; I really appreciate your work. Thank you for such in depth discussions of such esoteric yet fascinating products of human ingenuity!
Місяць тому
Thank you very much for making this video. Gave me perspectives worth thinking about.
Given your seeming interest in early digital computers, you might be interested in the story of the development and operation of the first digital satellite, which was also the first Dutch satellite. It was called ANS, or Astronomical Netherlands Satellite. It's sadly quite unknown in the larger spaceflight community, and I've been told its development and operation had some rather interesting events and remarks! One such notable point being that the orbit it had been delivered to was far off-target, and any other satellite of the time would have been useless because of it, but because it was the first satellite with a reprogrammable computer, it was able to correct its scientific experiments to account for the unexpected orbit.
@ 10:22 - As you've previously covered, NAA Autonetics built the D-17B and D-37C (Minuteman 1 & 2) flight computers. The 17B ('61) was discretes, the 37C ('64) was IC based (Texas Instruments). However, the NAA Houndog/Navaho flight control computers preceded these designs and led to the VERDAN digital flight computer in '59 that first flew in the NAA A3J/A5 Vigilante, which was built in '61. This was a digital computer, with architectural features adopted in the AGC a few years later (primarily the data conditioning & interfacing circuitry). Although wholly digital, the construction initially used discretes and in later versions, ICs ('64-'65) following experience gained from the 37C. The VERDAN was licensed by Elliot in the UK with the intent to use it in the developing TSR-2. It was rapidly discovered it didn't have sufficient capacity to handle all the mission requirements for the aircraft, so the avionics design was under revision to have 2 of them in the airframe prior to cancellation. Elliots later went on to design the 920 for the Nimrod, Jaguar, and MRCA/Tornado. I'm not going to argue the toss about "which came first", but it was a close run thing around '59-'64 for the blue riband of FCC devices among a number of American and European manufacturers.
Now this is interesting because I can't figure out what made me forget to mention the VERDAN here. It's obviously a computer I'm pretty familiar with due to my previous videos.
@@Alexander-the-ok Would love to hear your take on this computer and it's precedants & antecedants (eg. MARDAN/SINS, VERDAN II) - it's a "lost" machine that deserves recognition. Autonetics' work in flight and guidance systems was astounding, and apparently shielded from public view due to their secret work on the Minutemen GS.
Remember going to an airshow in Dala-Järna where the air force historic flight were attending with a Viggen. And the announcer was a former Viggen-pilot and he noted how the current JAS-39 Grippen has more computing power in its ABS-brakes then the entire Viggen. Says something about how far technology has come and how clever the Viggen engineers were.
What an absolute gem of a video - strikes the balance of technical detail and concept of use perfectly. Subscribed and off to look at more of your work! Thanks. P.S. I see you also have a penchant for Soviet era tech, and how their engineers approach early computing/technology slightly differently to their Western counterparts. Would you consider looking at the Venera missions as a topic?
I really really want to do a Venera video. It’s already quite a heavily covered topic though….I’m in the process of deciding how I could do something original on it.
How about the transmission of image data from the surface (i.e. Both from a digital technology problem, and the engineering challenges in such an unprecedented environment); and the technology behind that? Also, have you ever considered collaborating with other UA-camrs (I'm not one myself BTW)?
DCS World has a very realistic simulation of the AJS 37. While it is a modernised model of the original Viggen, the cockpit instruments, CK37 and everything else is pretty much the same. If any of you wanted to fly it, i would highly recomend trying it in DCS. You can trial it for free for 14 days
Also after seeing the insides of the AJS cockpit in this video id say that the only real difference between AJ 37 and AJS 37 in DCS World are the weapons the viggen in game can carry
regarding translations of the flight manual: The manual for the Viggen in DCS feartures a couple of the diagramms shown in this video and they are vailable in english.
Next aircraft and video I guess is about the McDonnell Douglas F-4 Phantom II as that aircraft badly lacked a gun during Vietnam and the F-4E was introduced. Great video on the Viggen and you did do a good job of pronouncing Viggen! Hello from Sweden 👋
I remember being woken up one overcast summers morning by a Viggen in full splinter camouflage and Dayglo tail numbers seemingly ripping the sky apart as the pilot threw it around at low level, showing off to the Irish Air Corps lads before landing for an airshow that week. Must have been the early 90s, but they also sent over a Draken one year (which may have been Austrian, my memory is a bit fuzzy!) 😀 Fun times!
Im an engineer myself (tradesperson though). Love your videos, such an delightful way to look into topics with a perfect amount of info. Love watching them them!
The ability to make an IC based computer and mainframe using Swedish engineering guaranteed self sufficiency. This is strategically important for a potentially revolutionary technology and a defense industry. Hypohystericalhistory talks about this in his videos about Australian defense autonomy in terms of manufacturing, meeting national requirements, and ability to defend themselves against an advanced adversary immediately without relying on foreign allies.
the first digital flight computer was on the cf-105, and position fix through digital navigation was literally invented by the RCAF with the R-Theta navigation computer (Rho-Theta or VOR/DME). i will say though the Viggen is one hell of a plane regardless of who was first. So was the Draken. being Finnish, i have i high level of respect for those airframes.
15:50 The AJ 37 does not have an actual IMU. The nav system is not actually inertial, or at least not primarily inertial. As you say, IMU's were horrifyingly expensive in the 60's and not really a thing you could buy off the shelf, so the AJ 37's navigation system is primarily based on air data. It's a pure software solution, implemented as just another program in the CK37 - it had no separate IMU computer. Instead the CK37 uses air data and attitude information from the Attitude Direction Indicator (the artificial horizon) gyros to calculate a true velocity vector relative to the air, then takes that and compensates for wind (either calculated from measured ground speed from the doppler radar, or forecast wind entered into the computer) to calculate a ground-referenced velocity vector. Then it just integrates that every 103ms program cycle to continuously keep the position updated. There are two problems with this: 1) transverse (side-to-side) movement can't be calculated from air data, and 2) the air data sensors are too slow, they don't react quickly enough to make this work with sufficient precision. To fix the first issue the CK37 uses data from the autopilot's transverse-axis accelerometer (whose main function is to correct for sideslip in turns) to calculate transverse movement based off inertial data. It's not a super high precision instrument but it's good enough because acceleration in the transverse axis is typically weak and the velocity tends to sum to zero over time, claims the flight manual (and I guess the aircraft doesn't usually fly sideways, after all). To resolve the responsiveness issue it also uses two separate accelerometers for the other two axes to correct the air data-calculated vector for small and sudden movements. This is janky, yes, but it worked. It drifted more than a state-of-the-art IMU of the era did, but not so much that it was a problem in Swedish air force tactical use (they didn't exactly need to do ocean crossings with the Viggen). But on the flip side, it required almost no extra equipment in the aircraft apart from two extra accelerometers - no super high precision gyros, no dedicated IMU computer, nothing - it was almost a pure software solution, so it was really cheap. Also, IMU's of this era often had very long cold start times; they could take up to 30 minutes to align. The AJ 37's nav system cold booted in more like 30 seconds. The user-friendliness of this thing is just astonishing for the 1960's. You barely even need to set it up. You just punch a 4-digit code in for your starting base as part of your waypoint data entry, and during your takeoff roll the CK37 will detect which of the runways you are on (runway headings for all Swedish bases are stored in memory!) and initialize the navigation program to the center of the runway just about when the aircraft rotates. This might be off by a few hundred meters, but it's certainly good enough to get you to your first landmark where you can take a fix and correct for drift. No manual initialization and no alignment needed!
Fuel and diversion calcs every ten minutes Alex? Giving away your backgound a little?! Another excellent video. Very interesting and clearly huge effort in the research. BZ. Next video - Harrier (angle rate bombing system)? Also, please DO release a video on the AIM-9!
The "Lansen" @9:05 is a SK60/SAAB105 ;) The AJ37 even had a automatic bombing mode, where the pilot held the trigger to hand over the drop to the computer. The only real reason for Sweden to stay out of NATO was to be able to use entry as a threat towards Russia/USSR if they messed with Finnland.
The use of core memory for the Space Shuttle's main computers (AP-101B) proved quite helpful during the investigation of the Challenger disaster. Since it was non-volatile the memory contents survived the break-up and allowed the system's state (sensors, etc.) to be reconstructed. Later they switched to semiconductor memories but also included flight data recorders.
I was supposed to as part of this video but just didn't have the time. I'm probably getting myself a decent VR headset sometime soon so I'll try it out then.
@@Alexander-the-okit's easily one of the better modeled aircraft, and fascinating. The HUD functionality is completely different from later NATO standards, but extremely well thought out and usable.
I SUCK AT AIRCRAFT IDENTIFICATION AND GEOGRAPHY:
I start the video by annoying a lot of people by calling Finland and Iceland ‘Scandinavia’.
Thanks to @CasGRos (AKA Sacgr) for spotting a mistake on the Patreon early access before the video even released here: the aircraft shown at 9:05 is technically not a Lansen. It is a trainer aircraft.
Also, the 'AJS-37 cockpit' is actually from a Gripen.
3:37 The canards couldn’t move like that. They were basically landing flaps to enhance the STOL capability.
12:30 Apollo 10 launched in May 1969 is probably more correctly referred to as the first flight of a ‘production’ AGC since it was the first to contain a working version of the Luminary landing program.
At 29:20 it sounds like I make an error but I don’t - I just omitted some detail that would have made it clearer. The ‘1.6 failures per year’ also included running time on the ground in addition to the stated 150 flight hours.
As a finn, I appreciate your approach. Trolling is a art!
IS your next video about the f35's cannons? Ive heard they are pretty accurate
On that note, please make a video about f35 if you can
specifically a Saab 105 trainer/light attack aircraft.
38:30 No variant of the AJ 37 ever had a map display, that was only on the JA 37.
As a dane im offended we weren't mentioned in the intro. We did... Erm.... We were kinda cool in the 1800...
Everyone hates the danes
Your country developed one of the most effective antipersonnel mines* in history: the LEGO block
* effectiveness highest against barefoot and sleepy enemies
Ni döda i alla fall en del nazister !
Vindkraft!
Why would you be mentioned? The three Scandinavian countries are Norway, Sweden, and Finland. :P
I may have missed it, but if anyone is curious CK37 stands for: "Centralkalkylator 37" i.e. literally "central calculator 37." (The '37' from the Viggen air force number for the type)
Saab's ease of use philosophy trickled down into their cars, in their instrument panel layouts and ergonomic. I drive a 9000 and the EDU ( Electronic Display Unit) in the dash is very helpful and very very accurate in showing its range, average fuel consumption and real time fuel consumption, it was incredible for its time in 1986.
Also my favorite is its minimally lit green dials and readings, it reduced glare at night, it made me frustrate driving other cars with brightly lit dash, so much glare at night.
@@worawatli8952 My mom’s Subaru in roughly that same year was similar! So few did that well back then.
Two car companies that do Turbo very well too.
Hi from another 9000 Aero driver :)
That's the first thing I though about hearing Viggen computer calculating estimated time of arrival on target.
I hate instrument glare. I always run my lights extremely low
Is it expensive to change parts?
Fun video, particularly since I for 14 years worked with one of the CK-37 programmers. Liked the comments regarding their workflow because when we met, he where Saab Autos Chief ICT Strategist, later becoming a key GM Europe strategist. Having been a system ops and governance manager for 10 years, through our discussions and with his logical thinking, often referring to CK-37, made me adopt much of his systemic thinking, which has been of tremendous advantage for over the last 30 years. I met a couple of others from that team, and they also had a strong enterprise systemic thinking, a treat that I still use. In principle, Keep It Simple, Stupid, go to the core, and drop the "fluff". Thanks for the video.
Regarding the YT premie;r the tone shift from that epic sci-fi count down animation with the heart pumping music, to Abba footage is INSANE. One for the books really.
The updated AJ 37, the AJS 37 Viggen had, as the film suggests, a digital map of Sweden stored in its memory. This map however was not displayed to the pilot. There was no map display in the cockpit (The JA 37 had one, but that´s a completely different beast). The map consisted of elevation data, and this data was compared with data from the radar altimeter and the navigation system. Comparing the stored data with the radar data the nav system could correct itself automatically, not relying as much on manual navigation fixes.
One thing that strikes me, as having tried the Viggen and various other aircraft in DCS, and even the 39C and E in simulators at Saab, is that the CK 37 is not only very advanced for its time, but also easy to use. For a non-digital pilot the output from the CK was mostly presented in a way that a 1970's pilot was used to. Finding out if you hade all the fuel needed for the mission was as easy as checking the fuel gage. No need to enter a sub page in an MFD or on an UFC or manually entering a BINGO at the start of the mission.
Swedes have always been pretty good with user centered design. Same goes with cars, they did not think "how it is done", but "how would user do it".
The best anti ship missile of the 1980s was probably the P700 Granit.
Fired in salvos of atleast 4 missiles, they approached the target below the radar horizon.
One missile would briefly pop up and search for targets with its radar, relaying the targeting information to the rest of the swarm through datalink.
The radar and computer of the missile where not only able to detect ships, but to identify them as well, and was able to assign a number of missiles to different targets based on preset priorities.
NATO reporting name SS-N-19 Shipwreck.
The Soviets were able to make some excellent kit when they put their minds to it.
I've had a request to do a video on that before! I think I need to do some reading...
Wasn't that how the heavier P-500 bazalt worked aswell?
Also, as much as the p-500 launchers on the Slava may look weird, you most likely haven't seen the project 1234 ovod (nanuchka), what were they thinking with that
@@AddSomethingCreativeHere Cheap*, fast, expendable*, CIWS-protected means of getting a minimal viable salvo** of AShMs to a target that can also perform other tasks to some degree.
*Not really
**According to calculations during design phase, actual minimal viable number of missiles ballooned after Aegis & VLS-equipped vessels started entering service
This is so interesting!
@@theleva7honestly, I think the biggest nightmare now for AShMs is that one central command ship can utilize the SPY radars of every ship in the formation to direct every missile available from the VLS at any vampire that it might want to eliminate from the sky.
Provided that it works, of course. Can't exactly imagine the US shooting a bunch of missiles at a CSG* to test it.
I grow up a quarter mile from the Saab factory and airfield in the sixties. And remember when Draken came in for landing, and we where laying in the grass looking up. And then we kids saw the first flights of J37, When made sonic booms my mother always said now the is some important one visiting :-)
Lucky you
Saab is goated, best cars on earth. Don’t know much about their planes tho
It's worth mentioning that there are only 3 Scandinavian countries, the Nordic countries is the category with five
Yeah I'm going to get hundreds of comments about that aren't I?
@@Alexander-the-ok Only holding you to the highest standards :D
@@Alexander-the-ok Yep, but it's engagement atleast
Is the third Scandinavian country Denmark or Finland?
@@LostieTrekieTechieafaik Denmark, coz I used to play Eve-o with a couple of Finn's and some Danes who argued about it...for literally days, every times we had down time they would argue
These flight computer videos kick ass. I'm totally stoked for the next one too, at the hint of analog computing. There's some neat old film reels about mechanical naval gun control computers that could do All kinds of integration, differentiation, etc.. with rollers and cogs, racks and pinions..
Thanks! The brief clip of the mechanical components is from one of those film reels. Let’s just say I’m currently in the process of building some of those parts for the next video.
@@Alexander-the-ok only One Eh? :)
The animated film you’re referring to is one of my favourite watches of all times.
I love this plane so much, it is a true wonder.
It is one of the best marriages of task, system, and airframe there has ever existed. The navigation, the system symbology, and the sensors. They're seamless. When you fly an A2G mission in DCS, and see the radar display with the RWR and NAV circle, it's a buttery smooth experience. The cockpit design, the weapons, the airframe, they act in such a way that they allow you to think and fly and deliver.
That is a difficult thing to achieve for a2g missions without smart weapons. Especially in the 60s. Having tried this and other planes in DCS, I believe the viggen would be terrifyingly combat effective platform.
I bought the Tomcat instead of Viggen a few weeks ago... You just convinced me to get the Viggen soon.
@@2KOOLURATOOLGaming The only way I could describe the viggen in DCS is neat. Imagine everything you need to worry about in an A2G striker in the cold war, and most of it automated. Now do it transonic, being faster then the contemporary interceptors. The way navigation turns to targeting to weapons deployment to egres. Its beautifully smooth, and it can handle pop up targets of opportunity too.
@@2KOOLURATOOLGaming They do different roles. The Viggen is useles in DCS AA combat while the Tomcat has very very funny low speed handling (don't be afraid of disabling the flight computer when trying things out) and the as with all Eagle Dynamic missiles the AIM-54 is very poorly modelled so the F-14 lacks some of its bite too.
@@ivaniii9707the aim54 is fine and realistic
@@HowIsAsh It is very bad. Last time I played it didn't loft and before that it's acceleration was worse than a Sparrow as well as it losing track to targets flying straight. DCS has some of the worst missile modelling in the business and unless they brick every missile around it wouldn't be a good day for ED.
The Viggen module in DCS is one of my favorites for its chunky buttons and numerical data input. By today's standards the input is crude, but it has a bespoke and practical elegance that cannot be denied. Entering a flight path with preprogrammed attack coordinates is easier than slipping in a NES cartridge and inputting the Konami code. The radar also displays vectors superimposed over the look down radar returns which can be adjusted and calibrated in flight. It is just so much fun to fly in that simulator. If you don't have/can't play/aren't otherwise interested in DCS, I would recommend you find a friendly flight sim nerd in your area and just spend an afternoon pushing its buttons, you won't be disappointed.
*pleased Swedish noises*
Also, as a Swede reading those acronyms and your growing confusion was very enjoyable 😅
Dropping a like isn't enough. I want to thank you for investing the effort to make this video. I enjoyed every pixel. The pre-4004 era is an underappreciated goldmine of computer history and I'm so glad to have a worthy UA-camr covering the topic in depth.
One of my favourite Viggen facts is that the engine is a derivative of an airliner turbofan that Saab^H^H^H^H Volvo equipped with an afterburner
same with the B-1B
Volvo manufactured the engine.
Same engine used by DC-9s and MD-80s widely used by Scandinavian Airlines at the time. (Doesn't have anything to do with the Viggen, but kind of a fun fact imo)
@@theflyinggasmask sadly none of the SAS aircraft received afterburning engines
@@RoamingAdhocrat Just imagine, Stockholm to Copenhagen in 10 minutes lol
You might be my favorite youtube channel. I always look forward to your uploads, and I rewatch them regularly just because there's so much to absorb and learn from.
The Marviken nuclear powerplant was actually just about finished. It was shut down because the Swedish nuclear weapons program was, so the main plutonium production purpose wasn’t needed anymore. It was a heavy water BWR with questionable safety so it was determined not to use it. An oil boiler was installed instead and the plant was used for reserve power.
More regular BWRs was built instead for Swedish power needs.
To elaborate on this, most of the access piping was at the bottom of the reactor vessel which made it vulnerable to shakes and whatnot. A burst pipe would empty the vessel in a hurry and cause a bit of an issue. At the outset this was not considered very significant, but updated safety requirements during the build period lead to the decision to discontinue it.
I plan to visit that place next summer.
Wow! So both Sweden AND Switzerland had nuclear weapons programmes? That's kinda crazy 😮
@@mrkeogh It was the thing to have at the time.
@@mrkeogh Swedens is very very interesting if you like the more "conspiracy" side of it lol. It was canned in 1972 BUT technically the Gripen can carry tactial nukes and the Bandkanon could also technically fire them despite being a howitzer. There are also very diffrent accounts of it with people that worked on it saying that they never got anywhere and others saying they actually touched a working nuke that was just never detonated. There is a somewhat popular theory here in Sweden when talking about it that "we probably don't have nukes but i wouldn't be suprised if the parts are laying around and we can assemble them in a day if we truly want to". Although it's said more as a joke it could actually be the case
@@mrkeogh The Swedes shut down their nuclear weapons program roughly 6 months before the first three devices would have been ready.
At 9:06, I am pretty sure that the aircraft you called the Lansen is actually the SAAB 105 trainer, based on the thicker nose, the lack of cannons and the position of the air intakes. Otherwise, this is an amazing and really well-explaining video!
Came here to say that
100% correct. The photo location is the museum at former F10 fighter wing in Ängelholm.
Besides your videos being absolutely top of the line, “Alexander the ok” is the best channel name of all time! Can’t wait for the next one
Unfortunately Sweden's "totalförsvar" more or less disappeared after the end of the cold war. Finland kept it's own though.
Yeah :(
Yep, great move that was...
Totalförsvaret involved the whole contry, not just "all people".
YESSSSS let's go!!! The viggen is the plane that got me into dcs, and later on into aerospace engineering in general, all those years ago. The first principles aero research on the configuration is unreal, especially from such a small nation. The nasa paper is a great read.
Not to mention the unreal digital computer and hud (wayyy ahead of its time) license built modified engine, etc. Too many things to list :D
Another great video. Big thanks for putting these together. Your presentation is professional and you are clearly very passionate about the subjects which makes these ever more enjoyable to watch.
That follow on videos is definitely about the B-29 turret control system with lead calculations and gunner switching.
I reckon you might be onto something there
Ah, good guess! I was thinking perhaps it was the fire control for the A-10, but the analogue part should have eliminated that. I have a lot of admiration for the gunnery system of the B-29, fantastic piece of kit especially once the radar rangers were added and the gunners didn't have to worry about setting range manually.
regarding the matter of mounting the early IC packages on aluminum, with the boards on each side.. I worked with military avionics in the 70's and 80's, and we had to provide heatsinking for simple TTL IC's. That stuff used a fair bit of power, and when you have to operate properly at mil temperatures (125C? I forget...), you do have to work to get that heat out of the avionics. For the earlier logic types, I imagine the power dissipation was even worse.
How did I forget to mention that the aluminium was basically a heatsink? That was pretty much the main reason it was used haha.
Yes, having 2 5V power supplies, each capable of 30A, with one being used to power the memory and IO, and the other being pulsed at 400Hz, to power the actual arithmetic systems, because otherwise the computer would melt. Even with that you had 4 120mm fans running if you were operating it on the service bench, just to keep case temperature below 70C. It was a very effective pie warmer, and kept coffee hot as well while running the diagnostics tests. Then open it, and play swap the cards, because they would always have slight timing differences, so you would mix and match. Hard to change an IC on a vapour phase reflowed card, where there are DIP packages on both sides of the board with pins between the other side package.That involved a lot of filing and work to cut the old IC out, leaving the leads, and thin them down to allow the new one to be soldered to the old leads. Most common failure was a 5474, it would reliably be the faulty one in that position.
Cray solved the problem by immersing the entire computer in cooling fluid.
@@chrismofer Aircraft did it a similar way, using the LOX supply to the pilot as part of the recirculating cooling air, and thus serving both to cool the avionics and also give the pilot breathable oxygen flow at something approaching tolerable. Then for the extra cooling needed they simply used a pure ethanol water blend (around 140 proof) as evaporative cooling to make up the rest. Those drums of coolant were more securely locked up than the munitions were, for some reason.
Both TTL and (especially) ECL draw a fair amount of power even when idle. With the later CMOS (found in virtually all modern devices) current is (essentially) only consumed during switching with only a small quiescent power draw due to leakage. Before CMOS was perfected though the tradeoff was slower and low(er)-power (TTL) vs. fast but power-hungry (ECL).
3:51 it’s worth noting that the canards on the viggen were not actuated as the canards on the EF typhoon, Gripen etc. they were flaps actuated by the gear being extended or not and were the viggens flaps moving more air under the huge double delta
Good spot! I never thought about that when reviewing that animation.
Yes - they were more a "vortex creator"
Just one small thing, the fact that the ferrite core memory is so resilient, is not always an advantage, on military hardware, often you don’t want info to fall into the wrong hand’s, even in the case of a crush.
I never thought of this. I wonder to what extent the code/variables were encrypted. That would be trivial to do today but not so much in the 1960s.
@ indeed, especially considering the additional computational effort involved (this is one of the reasons that systems like the javelin ATGM, use FPGA’s that are literally being reconfigured and reprogrammed from scratch each time they are armed, the GNC algorithm is the most important thing in that case).
Great video either way 🙏👑
@@AG-pm3tc The most valuable secret would be the list of secret airstrip locations. Once stolen, they could all be added to strategic target lists for use by nuclear planners, potentially wiping out the entire air force, including ground equipment, personnel and parked aircraft. Fortunately, this could be wiped in a fraction of a second along with the code, provided there was a special way to disable the write protection during self-destruct. Much faster than destroying paper maps in the pilots pocket.
@@johndododoe1411 _"The most valuable secret would be the list of secret airstrip locations."_
My thoughts exactly. That's not the kind of thing you want to keep in non-volatile memory.
@@johndododoe1411 Thinking of it it could be done while still leaving bunch of variables that are meaningless without context (but potentially very useful for determining what went wrong)
Its so refreshing to not be talked to like im a complete idiot! Its so hard to find a creator that assumes his audience are educated adults
that's so real. so many UA-camrs just read the same basic information from Wikipedia or have chatgpt do it for them
Yes, I find myself having to pause and rewind very often if I want to really 'get' it but in this day and age that information density is unheard of
I discussed this video with my aging dad who worked on the CK37 on Datasaab and loaded data to it. Personally I worked on the bodies of the last three AJ37s to be delivered to the Airforce, and on JAS 39 Gripen. They are both awesome planes. The reverse jet on Viggen was my favorite, and the Viggen looked awesome before painting them green. Viggen means "the Thunderbolt", but it is also a kind of duck. "Gripen" means "the Grip", which is a cross between a dragon and an eagle. It is the symbol on the Scania semi-trucks, and it was inherited from Vabis lorries.
Kickass intro. Made some made, others proud, and with that heavy metal, this right hook has got me excited for whats next. Dayum. You're a legend.
1:32 Finland winter war aviation and armor strategy: "We can't have tank or airplane losses if we don't have tanks or planes."
The Algorithm serves me MUCH retro computer content and this is about the best I've ever seen. The way you cover so much (needs, contemporaries, logical design, physical circuit building, programming methods) all in the one video. Nicely done
One nitpick: A HUD is properly expanded to Head Up Display, as labeled at 20:06 , because we humans only have the one head. A Heads Up Display would be needed for Zaphod Beeblebrox.
Well as long as the pilot knows where their towel is I don't suppose the semantics really matter...
Except "Heads up display" sounds more fluid. Grammatically, it still makes sense as the plural indicates the collective of all the users' heads being up, so unless there is only ever one built. Languages, like Japanese, often aren't so distinctive with respect to plurals anyway, as one can explicitly state the number in question if it is important in the context of the statement, which it seldom is.
@ But the manual on-screen at the time point I indicated does not use the plural. And English is not Japanese, nor is Alexander, nor is the Viggen.
One place where “heads-up” is absolutely correct is when you’re warning a group of people (i.e. more than one person) that some sort of danger is headed their way, because multiple heads do need to look up.
And imprecise rules about grammar have zero business in aviation, engineering, or anything else that involves safety.
Well half of all people have more than one head 😏
Have you ever seen a cockpit Billy?
”Saabs Automatiska Navigations Kalkylator” stands for Saab’s automatic navigation calculator.
Swedish can be a shocking language.
Sometimes similar to english, but some words or phrases are WILDLY different, with little reason but historical coincidence.
@@NoOne-ef7yuMy personal favorite is when people from the U.S hears about "automatisk fart kontroll" in the Viggen, which is "automatic speed control" in case someone reads this and doesn't know.
I find that knowing some German helps a lot with being able to read the Nordic languages. There's a lot of overlap in the vocabulary. Fahren, lustig, etc.
@@alexhajnal107
Swedish is a north germanic language. German a west germanic language. So they share a common ancestor.
@@Conenion Yea. The degree of similarity is still rather striking.
Aaah, yes. A 10/10 documentary after a looong day. Thanks for your work!
I can't believe you just posted this. Just yesterday I thought about how great it would be if you'd post something about it.
Oooooh! Shit!!! The Viggie actually is one of my favorite aircraft in DCS!
So excited to see you cover this!!
BTW, Russian MIGs were using vacuum tubes till 1970-s. I have seen and touched MIGs blocks at a garage sale. Targeting system images were optically mirrored together by prisms. A mechanical gyro was the nicest block.
As I understand it tubes are more resilient to EMP, thats why they stuck with them.
Nothing wrong working with known good components.
I remember back in 2002 when NASA was looking for 286 CPUs for the space shuttle.
Or how the James Webb Space Telescope, launched in 2021, uses a RAD750 at 118 MHz, a radiation hardened version of the PowerPC 750, which was also used in the Nintendo Gamecube in 2000 (more precisely a PowerPC 750CXe at 486 MHz) and the 1997-1999 G3 Mac (at up to 400 MHz).
@@HappyBeezerStudios The large features in an older LSI are bound to be much less affected by cosmic radiation than the modern tiny features.
Excellent video! For anyone visiting the north of Sweden, right in front of Luleå AFB, there's a small but interesting museum, operated by enthusiastic volunteers (mainly retired pilots and maintenance crew) who are more than willing to answer your questions about these planes and share their stories about their time in the air force. Keep in mind that it's only open once a week though, so better check with the Luleå tourist office first.
> Five Scandinavian countries
[Finnish heavy metal person quaffs some beer]
All together now!
🎶🎶 [sick death metal backing] NOOORRDIIIIIIC
but can Estonia into nordic....?
@@HappyBeezerStudios Why not?
For those who wonder whate the text in the thumbnail says, here's a rough translation:
"For many executives at Saab, electronics was in the beginning of the 1960s still a question entirely subordinate to construction and production of aircraft, which naturally was Saabs main diet.
Terms like computers and datascience were still newfangled. But for a few key persons in the systems department, the insight into the arrival of computer technology had started to grow. Here at the end of the 1950s and start of the 1960s started a tentative development towards a computerisation, whose enormous development-power few only guessed at, and most had no perception of"
I forgot the thumbnail for the premier is hi-res so i wasnt really ever expecting that text to be readable! It’s just copy-pasted from one of the many source documents i used (that said I did paste something relevant in just in case it would be readable)
Wasn't Nokia an outgrowth of saabs computing efforts
@@flavortown3781 Nokia is Finnish. But there's a complicated history for Datasaab: en.wikipedia.org/wiki/Datasaab
41:36
as someone who has this as a module in DCS: my guess is that the "magnetic realign" and "stable platform" are references to the TERCOM system that automatically attempts to correct navigation drift using the radio altimiter and terrain features. this is yet another incredible ahead of its time feature in the viggen
16:50 The Viggen could also its navigation/fire control RADAR to perform update fixes as well-co-locating waypoints with visual landmarks helped in this regard. Also, at some point, the Viggen's navigation software included a coarse terrain-mapping system to further enhance accuracy.
Hear hear from Sweden!
Growing up in one of the major regimental towns in northern Sweden it was fun every time the Viggen pilots did a low run over the town at night and hitting the throttle. The car alarms were going off everywhere and we all laughed about it every time!
I've had the pleasure of standing very close behind both a Draken and a Viggen as they were taking off. Talk about thunder - and it was also the best way to clear blocked sinuses since I believe the starting fuel contained a lot of liquid oxygen? This was back before they dismantled the armed forces which we are currently desperately trying to rebuild in a hurry...
Luckily our arms industry is still rather strong and we still prefer homegrown solutions, although we just joined NATO and thus ended our neutrality and non-alliance.
Sadly Gripen isn't as majestic as Viggen, and it doesn't set off the car alarms at night, but we still own our air, sea and land!
Thanks for a greatly researched and presented video! I've flown the Viggen simulator once in the 90's which was rather interesting since I'm an engineer who's designing and building large computer systems, and I frankly thought the simulator was rather primitive - but I knew how old it was and that made it almost as impressive as the plane itself!
It took many great engineers and visionaries to design and build all those planes and supporting systems. Something we're proud of here!
p.s. I failed my one and only landing attempt in said simulator, but it was a spectacular crash since I attempted to land on the main road through the town of Östersund! It's a memory I'll never forget... ;)
What a fascinating video. I am happy that the Cold War never went hot, but wow, part of me wishes this beast got into action
Thanks. Yeah me too. If the cold war went hot we almost certainly wouldn’t even be here to discuss it.
Fascinating. This presses every single one of my nerd buttons in one fell swoop, thanks to the whole team for collating and presenting this. Cheers
An excellent overview of a remarkable machine. If you ever want to update the video, though, reach out to the Digital Combat Simulator community. They have the refitted AJS37 at their disposal and can get some excellent footage.
37:35 I’m amazed that an aircraft built when the Viggen was not only had a flight computer but had one that could record and store enough information to be used almost like a black box during testing of the aircraft.
No, the pilot was ejected merely by the aircraft tumbling violently after losing a wing. There was no system for automatic ejection.
@@erikgustavssonah, thanks. his use of the word “automatically” had made me think it was an automatic system. I’ve deleted that paragraph from my comment.
@@michaelimbesi2314 You can also -strike out- text by putting a - at the immediate start and end of a word or phrase (they have to abut the first and last letter). [Also * for *bold* and _ for _italic_ text.]
Love the IKEA VIGGEN parts coming together in the intro.
Just because it may seem like an obvious joke, doesn’t make it any less funny to me!
I wouldn't mind if IKEA starts selling Viggens.
3 decades in tech, engineer, I remember a day when I worked around others that could have created a system that lasted 3 decades. Now, I don’t think it’s possible, in fact, I don’t even think anyone can think in those terms anymore.
A one hour Alexander essay about a flight computer, what a birthday gift😄
Loved your Digital Fly-by-Wire Apollo Guidance Computer video! Thank you.
Love your videos. The excitement of the intros, the renders and animations, the nerdy details of the tech, the context, the archive footage - all come together to make a great narrative.
Also, the use of archive footage, practical demonstrations, and animation (albeit not stick figures) also reminds me of the best TV series of all time, 'The Secret Life of...' by Tim Hunkin and Rex Garrod.
Warching from Sweden, love your videos!
This video was ok Alexander can’t wait to see the analog computers. Love the focus the channel goes into on these topics
Thank you for the wonderful content as usual:)
What a joy to watch. Thanks for the enourmous amount of work crafting together each of these documentaries.
Not that it matters, but the aircraft at 09:14 is not Lansen, it's the trainer aircraft Saab SK 60.
Twin engine jet trainer, Saab 105 Florett, Swedish airforce designation SK60. :) Was in service until 2024, now replaced by a glorified Cessna.
Great video setup and design. Fantastic storytelling. I always learn something and have a blast doing so.
Actually 200kg computer that can replace crew member is a huge win out of the box. Ejection seat, all instruments, structural and body parts to create additional space would most likely add up to much higher weight
Absolutely. I suspect heat dissipation and reliability was the bigger cause for concern.
As a lover of all kinds of mechanical contrivances and computing machines; I really appreciate your work. Thank you for such in depth discussions of such esoteric yet fascinating products of human ingenuity!
Thank you very much for making this video. Gave me perspectives worth thinking about.
It's always a good day when ATOK uploads.
woah, so glad i got this recommended. keep up the good work!
Given your seeming interest in early digital computers, you might be interested in the story of the development and operation of the first digital satellite, which was also the first Dutch satellite. It was called ANS, or Astronomical Netherlands Satellite. It's sadly quite unknown in the larger spaceflight community, and I've been told its development and operation had some rather interesting events and remarks!
One such notable point being that the orbit it had been delivered to was far off-target, and any other satellite of the time would have been useless because of it, but because it was the first satellite with a reprogrammable computer, it was able to correct its scientific experiments to account for the unexpected orbit.
This is an absolutely fantastic suggestion. I’m adding it to my ‘research later’ list, thanks!
@@Alexander-the-ok Glad to hear it! If you need any help with translation, I'd love to help.
Incredibly awesome video!
@ 10:22 - As you've previously covered, NAA Autonetics built the D-17B and D-37C (Minuteman 1 & 2) flight computers. The 17B ('61) was discretes, the 37C ('64) was IC based (Texas Instruments). However, the NAA Houndog/Navaho flight control computers preceded these designs and led to the VERDAN digital flight computer in '59 that first flew in the NAA A3J/A5 Vigilante, which was built in '61.
This was a digital computer, with architectural features adopted in the AGC a few years later (primarily the data conditioning & interfacing circuitry). Although wholly digital, the construction initially used discretes and in later versions, ICs ('64-'65) following experience gained from the 37C. The VERDAN was licensed by Elliot in the UK with the intent to use it in the developing TSR-2. It was rapidly discovered it didn't have sufficient capacity to handle all the mission requirements for the aircraft, so the avionics design was under revision to have 2 of them in the airframe prior to cancellation. Elliots later went on to design the 920 for the Nimrod, Jaguar, and MRCA/Tornado.
I'm not going to argue the toss about "which came first", but it was a close run thing around '59-'64 for the blue riband of FCC devices among a number of American and European manufacturers.
Now this is interesting because I can't figure out what made me forget to mention the VERDAN here. It's obviously a computer I'm pretty familiar with due to my previous videos.
@@Alexander-the-ok Would love to hear your take on this computer and it's precedants & antecedants (eg. MARDAN/SINS, VERDAN II) - it's a "lost" machine that deserves recognition. Autonetics' work in flight and guidance systems was astounding, and apparently shielded from public view due to their secret work on the Minutemen GS.
Remember going to an airshow in Dala-Järna where the air force historic flight were attending with a Viggen. And the announcer was a former Viggen-pilot and he noted how the current JAS-39 Grippen has more computing power in its ABS-brakes then the entire Viggen. Says something about how far technology has come and how clever the Viggen engineers were.
What an absolute gem of a video - strikes the balance of technical detail and concept of use perfectly. Subscribed and off to look at more of your work! Thanks.
P.S. I see you also have a penchant for Soviet era tech, and how their engineers approach early computing/technology slightly differently to their Western counterparts. Would you consider looking at the Venera missions as a topic?
I really really want to do a Venera video. It’s already quite a heavily covered topic though….I’m in the process of deciding how I could do something original on it.
How about the transmission of image data from the surface (i.e. Both from a digital technology problem, and the engineering challenges in such an unprecedented environment); and the technology behind that? Also, have you ever considered collaborating with other UA-camrs (I'm not one myself BTW)?
DCS World has a very realistic simulation of the AJS 37. While it is a modernised model of the original Viggen, the cockpit instruments, CK37 and everything else is pretty much the same. If any of you wanted to fly it, i would highly recomend trying it in DCS. You can trial it for free for 14 days
Also after seeing the insides of the AJS cockpit in this video id say that the only real difference between AJ 37 and AJS 37 in DCS World are the weapons the viggen in game can carry
@@freoxide7426 Well, our version came to be when the Gripen programme was picking up speed. So they gave it the Gripen's weapons, too.
Holy crap, that grippen intro song is AMAZING
i love flying the viggen in dcs world and i love being able to put mental examples of use cases i have been in in dcs through out this
regarding translations of the flight manual: The manual for the Viggen in DCS feartures a couple of the diagramms shown in this video and they are vailable in english.
Alexander, I love your videos. You always go into such amazing detail and provide so much information. Thank you! :)
I have been praying for someone to make this video, thank you!
The loss to the offshore industry is certainly our gain. Thank you very much for sharing your enthusiasm for engineering!
"Troll A Gas Platform" Man, someone was having fun in Scandanavia with that name.
Next aircraft and video I guess is about the McDonnell Douglas F-4 Phantom II as that aircraft badly lacked a gun during Vietnam and the F-4E was introduced.
Great video on the Viggen and you did do a good job of pronouncing Viggen! Hello from Sweden 👋
Great presentation, very enjoyable!
Subbed.
I'm really impressed by how they optimized the coding to save data power and memory back then.
I remember being woken up one overcast summers morning by a Viggen in full splinter camouflage and Dayglo tail numbers seemingly ripping the sky apart as the pilot threw it around at low level, showing off to the Irish Air Corps lads before landing for an airshow that week. Must have been the early 90s, but they also sent over a Draken one year (which may have been Austrian, my memory is a bit fuzzy!) 😀
Fun times!
Between you & "not a pound from air to ground" I have endless aviation ear candy throughout my day.
I just have to say you do excellent work. Your videos are great. Well done Sir, thank you.
Im an engineer myself (tradesperson though). Love your videos, such an delightful way to look into topics with a perfect amount of info. Love watching them them!
The ability to make an IC based computer and mainframe using Swedish engineering guaranteed self sufficiency. This is strategically important for a potentially revolutionary technology and a defense industry. Hypohystericalhistory talks about this in his videos about Australian defense autonomy in terms of manufacturing, meeting national requirements, and ability to defend themselves against an advanced adversary immediately without relying on foreign allies.
Fantastic to have these recent tech history vids
the first digital flight computer was on the cf-105, and position fix through digital navigation was literally invented by the RCAF with the R-Theta navigation computer (Rho-Theta or VOR/DME). i will say though the Viggen is one hell of a plane regardless of who was first. So was the Draken. being Finnish, i have i high level of respect for those airframes.
the 105s computer was talked about in the video, ICs are the key component here. Did you even watch it or was this comment made early on in runtime?
@@xiphosura413 he talked about the computer in the F-106, i'm talking about the CF-105. but i can tell that's just an honest mistake on your part.
15:50 The AJ 37 does not have an actual IMU. The nav system is not actually inertial, or at least not primarily inertial. As you say, IMU's were horrifyingly expensive in the 60's and not really a thing you could buy off the shelf, so the AJ 37's navigation system is primarily based on air data. It's a pure software solution, implemented as just another program in the CK37 - it had no separate IMU computer. Instead the CK37 uses air data and attitude information from the Attitude Direction Indicator (the artificial horizon) gyros to calculate a true velocity vector relative to the air, then takes that and compensates for wind (either calculated from measured ground speed from the doppler radar, or forecast wind entered into the computer) to calculate a ground-referenced velocity vector. Then it just integrates that every 103ms program cycle to continuously keep the position updated.
There are two problems with this: 1) transverse (side-to-side) movement can't be calculated from air data, and 2) the air data sensors are too slow, they don't react quickly enough to make this work with sufficient precision. To fix the first issue the CK37 uses data from the autopilot's transverse-axis accelerometer (whose main function is to correct for sideslip in turns) to calculate transverse movement based off inertial data. It's not a super high precision instrument but it's good enough because acceleration in the transverse axis is typically weak and the velocity tends to sum to zero over time, claims the flight manual (and I guess the aircraft doesn't usually fly sideways, after all). To resolve the responsiveness issue it also uses two separate accelerometers for the other two axes to correct the air data-calculated vector for small and sudden movements.
This is janky, yes, but it worked. It drifted more than a state-of-the-art IMU of the era did, but not so much that it was a problem in Swedish air force tactical use (they didn't exactly need to do ocean crossings with the Viggen). But on the flip side, it required almost no extra equipment in the aircraft apart from two extra accelerometers - no super high precision gyros, no dedicated IMU computer, nothing - it was almost a pure software solution, so it was really cheap. Also, IMU's of this era often had very long cold start times; they could take up to 30 minutes to align. The AJ 37's nav system cold booted in more like 30 seconds.
The user-friendliness of this thing is just astonishing for the 1960's. You barely even need to set it up. You just punch a 4-digit code in for your starting base as part of your waypoint data entry, and during your takeoff roll the CK37 will detect which of the runways you are on (runway headings for all Swedish bases are stored in memory!) and initialize the navigation program to the center of the runway just about when the aircraft rotates. This might be off by a few hundred meters, but it's certainly good enough to get you to your first landmark where you can take a fix and correct for drift. No manual initialization and no alignment needed!
Fuel and diversion calcs every ten minutes Alex? Giving away your backgound a little?! Another excellent video. Very interesting and clearly huge effort in the research. BZ. Next video - Harrier (angle rate bombing system)? Also, please DO release a video on the AIM-9!
i do seriously hope the upcoming video is on the F-106 or F-102, they're two of my alltime favourites.
The "Lansen" @9:05 is a SK60/SAAB105 ;)
The AJ37 even had a automatic bombing mode, where the pilot held the trigger to hand over the drop to the computer.
The only real reason for Sweden to stay out of NATO was to be able to use entry as a threat towards Russia/USSR if they messed with Finnland.
10/10 video once again already excited for the next one😊
The use of core memory for the Space Shuttle's main computers (AP-101B) proved quite helpful during the investigation of the Challenger disaster. Since it was non-volatile the memory contents survived the break-up and allowed the system's state (sensors, etc.) to be reconstructed. Later they switched to semiconductor memories but also included flight data recorders.
I can so appreciate your "dead bug" skills!
lol it's so sloppy. The soldering is terrible and I messed up the component spacing.
@Alexander-the-ok looks great to me, I would fly with it!
An interesting cross between cordwood and through-hole construction.
Such great Videos!
Your videos are consistently fascinating. I’m a total layman when it comes to this stuff but it’s all enjoyable nonetheless
Have you gotten onto DCS and given the computer a spin? Well worth the time to learn, the Viggen is such a fun jet in DCS.
I was supposed to as part of this video but just didn't have the time. I'm probably getting myself a decent VR headset sometime soon so I'll try it out then.
@@Alexander-the-ok TrackIR is fine. I'm using that, even though I have a VR-headset as well.
@@Alexander-the-ok It's a blast. Just be aware that it may become moderately addictive, and harmful for your wallet.
@@NiklasAndersson7 GrassMonkeySims IR solutions are even better than TrackIR, and cheaper. ;)
@@Alexander-the-okit's easily one of the better modeled aircraft, and fascinating. The HUD functionality is completely different from later NATO standards, but extremely well thought out and usable.
Creo = 10/10, just kidding its a 10 for soooo many other reasons, stellar work
I love your videos, i enjoy playing them at night while i go to sleep
Thank you for the obligatory rock music fighter montage in the intro. Reminded me of being a kid and having plane videos on VHS.