An excelent overview of Saturn V's flight guidance control system. - Page 1
Forum section: electronics / general

author: BrianHG
author_rank: Super Contributor
timestamp: July 16, 2019, 10:31:10 pm
content: Enjoy!

author: BrianHG
author_rank: Super Contributor
timestamp: July 17, 2019, 02:43:39 am
content: @1:27The museum staff obviously never saw one of Linus' shows, they let him hold the actual computer. I'm surprised he didn't accidentally drop it.

author: BrianHG
author_rank: Super Contributor
timestamp: August 07, 2019, 03:58:14 am
content: Another Saturn V Doc from Curious Droid...This one covers the difficulties of how the flight computer needed to compensate for the rocket's dynamics.Yes, he describes the computer control feedback loop and that with such slow computing power, the sensors on the feedback loop had analog filters they had to tune due to the flexibility of the rocket's structure oscillating...

author: BrianHG
author_rank: Super Contributor
timestamp: August 08, 2019, 06:10:31 am
content: Part #2: (Smarter Everyday)

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 08, 2019, 07:10:11 am
content: Many people don't realize how much of a revolution the space program computers were. The flown hardware was the first fly by wire system, the first example of what we would now call a RTOS. Of course there was more hardware to be found in larger ground based computers. A lot of concepts invented or implemented in that computer went on to be mainstays of computing in general up to this day.

author: sash
author_rank: Newbie
timestamp: August 08, 2019, 08:49:59 am
content: Great share

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 08, 2019, 01:06:53 pm
content: Quote from: Mr. Scram on August 08, 2019, 07:10:11 amActually, not quite.The very first plane in history that is known to have a preliminary FBW system is the Tupolev ANT-20 in the 30's (that wasn't very reliable apparently though).Then there was the Avro CF-105 Arrow in the 50's. Never went past a few prototypes though.

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 08, 2019, 01:27:06 pm
content: In the Huntsville, Alabama NASA’s museum has a Saturn V inter-stage coupling ring, and if I recall correctly, the guidance computer is assembled in the periphery.The ring is huge, and is chock-full of boxes and harnessing.Huntsville is not really in the tourist path, but I was lucky to visit a nearby factory. Someone suggested that I should take a side trip to Huntsville and visit the museum.It has many items related to rocket propulsion systems, not only about the Saturn.I am glad that I visited, and can strongly recommend that if you find yourself nearby, to set aside an afternoon to visit it.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 08, 2019, 02:27:22 pm
content: Quote from: SiliconWizard on August 08, 2019, 01:06:53 pmThe entire space program arguably consisted of prototypes. That being said the ANT-20 just had electronic controls instead of mechanical ones. Wikipedia states about the Apollo hardware "The first pure electronic fly-by-wire aircraft with no mechanical or hydraulic backup was the Apollo Lunar Landing Training Vehicle (LLTV), first flown in 1968." The LLTV had a flight computer decide the output based on the pilot input. This made it properly fly by wire in the modern sense, rather than having control surfaces powered by electricity but controlled by the pilot in the conventional sense. The thrusters of the LLTV and later landing craft were too complex to pilot manually so an intermediary fly by wire system was required.Apparently the CF-105 had a tube based flight computer and fly by wire in the same sense as the LLTV, but information is sparse and not very definitive. It is obvious the designers used computers for the design itself and apparently wherever else they could find an application.

author: Homer J Simpson
author_rank: Super Contributor
timestamp: August 08, 2019, 03:17:28 pm
content: Full video

author: David Hess
author_rank: Super Contributor
timestamp: August 08, 2019, 09:57:24 pm
content: Quote from: Mr. Scram on August 08, 2019, 02:27:22 pmI think hand assembled would be more accurate. Some cars are built this way. The same construction methods are still used for some industrial products where the volume is low.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 08, 2019, 10:35:08 pm
content: Quote from: David Hess on August 08, 2019, 09:57:24 pmConsidering each iteration was somewhat unique due to the iterative development and definitely highly experimental I feel the prototype moniker for space program hardware isn't a reach. Those hand built cars are type rated and built to the same design and specifications each time. Bespoke cars aren't quite in the same category as cutting edge spacecraft that we think won't blow up too much. Both the Apollo disasters underlined the design very much being a work in progress. That's no wonder when you're trying to build the most powerful machine to date for purposes never achieved before.

author: Miyuki
author_rank: Frequent Contributor
timestamp: August 09, 2019, 06:57:27 pm
content: Quote from: Mr. Scram on August 08, 2019, 02:27:22 pmFly by wire is nice, and can enable to fly object that cannot be controlled by human otherwise (even something as "simple" as quadcopters)But also as many accident during history shown us mechanical backup is still neededAnd for example commercial planes went from era of purely FBW to have mechanical backup again, even hydraulic systems tend to have mechanical backup because of long term accident records

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 09, 2019, 07:49:49 pm
content: Quote from: Mr. Scram on August 08, 2019, 02:27:22 pmNot exactly IMO. A frequent definition of a prototype is some iteration of a product similar or close to the final version, meant for testing purposes but not to be used in its intended final context. So I'd say small series instead. The CF-105 I mentioned were all prototypes, in the sense they never went past the testing phase AFAIK.But hey your definition may be a little different... you could also consider that all space missions were actually tests in their own right. Why not.Quote from: Mr. Scram on August 08, 2019, 02:27:22 pmAgain a question of definitions. I consider a FBW system as one that controls all, or at least the main control surfaces, as well as the engines, by means of electric signals instead of purely mechanical links, and that keep the mechanical controls very close to the parts being controlled. That would allow for instance to make a plane much lighter, and probably easier to maintain, even when no computer is involved.To me it doesn't have to be "computerized" to qualify for being a FBW system. Of course when the electric control is in place, the idea of controlling it all by computers becomes almost obvious once you have the technology. In the 30's, it was just not realistic. In the 50's, it still required heavy tube-based stuff. Very heavy and not that reliable under vibrations and stuff. So only in the 60's that began to become a real option.

author: Gyro
author_rank: Super Contributor
timestamp: August 09, 2019, 07:53:44 pm
content: I suspect that most interested people already know this, but just on the off-chance, all the Saturn V / Apollo manuals are available on line...Saturn V flight manual:https://www.history.nasa.gov/afj/ap12fj/pdf/a12_sa507-flightmanual.pdf(Includes the instrument ring, emergency escape systems, ground control, gantry and all sorts of fun stuff).Command Module overview:https://www.hq.nasa.gov/alsj/CSM06_Command_Module_Overview_pp39-52.pdfAll of the LEM related manuals:https://www.hq.nasa.gov/alsj/alsj-LMdocs.html