Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:>> There is a lot that can go wrong, often pilot error like the one I >> followed last week that crashed in a field near Schiphol airport, >> pilot had one engine throttled down.. (propeller 2 engine plane) >> without knowing it (he did it himself) so when steering towards the >> runway the plane tilted one way and he lost control.. > > There was one similar in Nepal, probably caused by the first officer > pulling the wrong handle feathering the engines instead of lowering the > flaps, like because he would normally be flying in the left seat as a > captain, but on this flight he was an instructor so he was in the right > seat...Nepal ATR 72 Crash 15 Jan 2023 https://www.youtube.com/watch?v=OnuVPUsz9VE Flight YT-691 Nepal Yeti Airlines ATR 72 Crash First Explanation by the ATR Airline Pilot https://www.youtube.com/watch?v=SOTWCrjbHN8 An unbelievable mistake | Yeti Airlines flight 691 https://www.youtube.com/watch?v=wIlO-TBDyaw Preliminary Report - Yeti Airlines ATR 72 Plane Crash Pokhara Nepal Jan 15 2023 #planecrash #pirep https://www.youtube.com/watch?v=5RsOlS93lxc HUMAN ERROR or MECHANICAL?! | Yeti Airlines flight YT691 illustrated https://www.youtube.com/watch?v=Ppo73zeAvDo -- MRM
load bank puzzle
Started by ●March 17, 2023
Reply by ●March 18, 20232023-03-18
Reply by ●March 19, 20232023-03-19
On a sunny day (Sat, 18 Mar 2023 13:38:44 -0700 (PDT)) it happened Lasse Langwadt Christensen <langwadt@fonz.dk> wrote in <9628b72f-aa02-40d2-b1e4-c5087e2c7083n@googlegroups.com>:>lørdag den 18. marts 2023 kl. 20.30.07 UTC+1 skrev Jan Panteltje: >> On a sunny day (Sat, 18 Mar 2023 10:28:46 -0700) it happened John Larkin= > >> <jla...@highlandSNIPMEtechnology.com> wrote in >> <kisb1ipbum7dulpqh...@4ax.com>: >> >On Sat, 18 Mar 2023 15:46:03 GMT, Jan Panteltje <al...@comet.invalid> >> >wrote: >> >>I have no idea what a FADEC is or what its internals are >> >>so I looked it up: >> >> https://en.wikipedia.org/wiki/FADEC >> >> >> >>Now I will stop flying!!!! >> > >> >Each FADEC is redundant, and gets power from both the airframe DC >> >supply and from a dual alternator on its engine. Thet are very >> >reliable. Most engine problems are mechanical or fuel related. Birds >> >are bad in jet engines. >> > >> >We sell alternator simulators that are used to test FADECs, which >> >furtunately people buy two at a time. It's kind of interesting, since >> >a PM alternator is basically a current source and the FADECs regulate >> >by shorting them. Our rev A box tended to blow up. >> > >> > >> >Some small planes have full-plane parachutes. They land hard but >> >survivably. >> >>Engine on fire, we circled and dumped fuel, then landed safely on one e= >ngine. >> > >> >Planes can fly on one engine, as long as the failed one doesn't toss >> >blades and tear a wing off or something like that. They have >> >"containment" that usually works. Engines are tested to destruction to= > >> >make sure the blades stay inside. >> There is a series on German satellite TV about plane crashes that happene= >d and they go into all the details >> and follow the guys evaluating what's left.. to find the cause. > >"Aircrash investigation" I'd guess, they are not bad but there's a few yout= >ube channels* >with actual pilots going through the accident reports, watching those make = >you realise >the TV shows are often far from accurateNo, not Aircrash investigation, forgot he name, German channel, think it was called 'Mayday' or something? Will let you know when I hit it again (hundreds of channels here)>*to mention a few, Mentour Pilot and blancolirio > >> There is a lot that can go wrong, often pilot error like the one I follow= >ed >> last week that crashed in a field near Schiphol airport, >> pilot had one engine throttled down.. (propeller 2 engine plane) without = >knowing it (he did it himself) >> so when steering towards the runway the plane tilted one way and he lost = >control.. > >There was one similar in Nepal, probably caused by the first officer pullin= >g the wrong handle feathering the engines >instead of lowering the flaps, like because he would normally be flying in = >the left seat as a captain, but on this flight >he was an instructor so he was in the right seat...Checklist are interesting too, I have a checklist for some thing I do, I went through it and sure enough one day I found out I had missed something... There was this airplane .. they went through the takeoff checklist but were interrupted by a stewardess making an appointment for the evening with one of the pilots (voice recorder was recovered) so they forgot to set the flaps for takeoff. Hundreds died, crashed at the end of the runway, ball of fire (full of fuel). You want a computer there saying: "Hey dummy, set your flaps or I will do it for you !!" Procedure is: Nobody allowed in the cockpit during prepare for takeoff, but human relations...
Reply by ●March 19, 20232023-03-19
On 2023-03-19, Jan Panteltje <alien@comet.invalid> wrote:> On a sunny day (Sat, 18 Mar 2023 13:38:44 -0700 (PDT)) it happened Lasse > Langwadt Christensen <langwadt@fonz.dk> wrote in ><9628b72f-aa02-40d2-b1e4-c5087e2c7083n@googlegroups.com>: > >>lørdag den 18. marts 2023 kl. 20.30.07 UTC+1 skrev Jan Panteltje: >>> On a sunny day (Sat, 18 Mar 2023 10:28:46 -0700) it happened John Larkin= >> >>> <jla...@highlandSNIPMEtechnology.com> wrote in >>> <kisb1ipbum7dulpqh...@4ax.com>: >>> >On Sat, 18 Mar 2023 15:46:03 GMT, Jan Panteltje <al...@comet.invalid> >>> >wrote: >>> >>I have no idea what a FADEC is or what its internals are >>> >>so I looked it up:7>>> >> https://en.wikipedia.org/wiki/FADEC>>> >> >>> >>Now I will stop flying!!!! >>> > >>> >Each FADEC is redundant, and gets power from both the airframe DC >>> >supply and from a dual alternator on its engine. Thet are very >>> >reliable. Most engine problems are mechanical or fuel related. Birds >>> >are bad in jet engines. >>> > >>> >We sell alternator simulators that are used to test FADECs, which >>> >furtunately people buy two at a time. It's kind of interesting, since >>> >a PM alternator is basically a current source and the FADECs regulate >>> >by shorting them. Our rev A box tended to blow up. >>> > >>> > >>> >Some small planes have full-plane parachutes. They land hard but >>> >survivably. >>> >>Engine on fire, we circled and dumped fuel, then landed safely on one e= >>ngine. >>> > >>> >Planes can fly on one engine, as long as the failed one doesn't toss >>> >blades and tear a wing off or something like that. They have >>> >"containment" that usually works. Engines are tested to destruction to= >> >>> >make sure the blades stay inside. >>> There is a series on German satellite TV about plane crashes that happene= >>d and they go into all the details >>> and follow the guys evaluating what's left.. to find the cause. >> >>"Aircrash investigation" I'd guess, they are not bad but there's a few yout= >>ube channels* >>with actual pilots going through the accident reports, watching those make = >>you realise >>the TV shows are often far from accurate > > No, not Aircrash investigation, forgot he name, German channel, think it was called 'Mayday' or something? > Will let you know when I hit it again (hundreds of channels here)yes that one: "Mayday", known as "Air Crash Investigation" outside of the United States and Canada and also known as "Mayday: Air Disaster" They read the investigation report, do some CGI, reenactments, show some report footage, news footage, photos, possibly do a scene visit, and interview some of the people involved. Also available in German: https://de.wikipedia.org/wiki/Mayday_%E2%80%93_Alarm_im_Cockpit/Episodenliste -- Jasen. 🇺🇦 Слава Україні
Reply by ●March 19, 20232023-03-19
On a sunny day (Sun, 19 Mar 2023 10:28:46 -0000 (UTC)) it happened Jasen Betts <usenet@revmaps.no-ip.org> wrote in <tv6o4u$i0f$2@gonzo.revmaps.no-ip.org>:>On 2023-03-19, Jan Panteltje <alien@comet.invalid> wrote: >> On a sunny day (Sat, 18 Mar 2023 13:38:44 -0700 (PDT)) it happened Lasse >> Langwadt Christensen <langwadt@fonz.dk> wrote in >><9628b72f-aa02-40d2-b1e4-c5087e2c7083n@googlegroups.com>: >> >>>lørdag den 18. marts 2023 kl. 20.30.07 UTC+1 skrev Jan Panteltje: >>>> On a sunny day (Sat, 18 Mar 2023 10:28:46 -0700) it happened John Larkin= >>> >>>> <jla...@highlandSNIPMEtechnology.com> wrote in >>>> <kisb1ipbum7dulpqh...@4ax.com>: >>>> >On Sat, 18 Mar 2023 15:46:03 GMT, Jan Panteltje <al...@comet.invalid> >>>> >wrote: >>>> >>I have no idea what a FADEC is or what its internals are >>>> >>so I looked it up: >7>>> >> https://en.wikipedia.org/wiki/FADEC >>>> >> >>>> >>Now I will stop flying!!!! >>>> > >>>> >Each FADEC is redundant, and gets power from both the airframe DC >>>> >supply and from a dual alternator on its engine. Thet are very >>>> >reliable. Most engine problems are mechanical or fuel related. Birds >>>> >are bad in jet engines. >>>> > >>>> >We sell alternator simulators that are used to test FADECs, which >>>> >furtunately people buy two at a time. It's kind of interesting, since >>>> >a PM alternator is basically a current source and the FADECs regulate >>>> >by shorting them. Our rev A box tended to blow up. >>>> > >>>> > >>>> >Some small planes have full-plane parachutes. They land hard but >>>> >survivably. >>>> >>Engine on fire, we circled and dumped fuel, then landed safely on one e= >>>ngine. >>>> > >>>> >Planes can fly on one engine, as long as the failed one doesn't toss >>>> >blades and tear a wing off or something like that. They have >>>> >"containment" that usually works. Engines are tested to destruction to= >>> >>>> >make sure the blades stay inside. >>>> There is a series on German satellite TV about plane crashes that happene= >>>d and they go into all the details >>>> and follow the guys evaluating what's left.. to find the cause. >>> >>>"Aircrash investigation" I'd guess, they are not bad but there's a few yout= >>>ube channels* >>>with actual pilots going through the accident reports, watching those make = >>>you realise >>>the TV shows are often far from accurate >> >> No, not Aircrash investigation, forgot he name, German channel, think it was called 'Mayday' or something? >> Will let you know when I hit it again (hundreds of channels here) > >yes that one: > >"Mayday", known as "Air Crash Investigation" >outside of the United States and Canada and >also known as "Mayday: Air Disaster" > >They read the investigation report, do some CGI, reenactments, >show some report footage, news footage, photos, possibly do a >scene visit, and interview some of the people involved. > >Also available in German: > >https://de.wikipedia.org/wiki/Mayday_%E2%80%93_Alarm_im_Cockpit/EpisodenlisteYes, looks like it! I see a next one scheduled on March 20 2023 I will check the satellite list I use https://www.tvdirekt.de/programmsuche.html search for Mayday wow, its today at 13:55 19.03.2023 - Sonntag13:55 Mayday Dokureihe, CDN 2019 Staffel: 19 / Folge: 3 Laufzeit: 50 Minuten Original-Titel: Mayday: Air Disaster Mit: Jonathan Aris, Ian Kilburn, Ira Donald Henderson, Marc Hickox, Irena Huljak, David Tompa Regie: Mark Mainguy Im April 1994 startet der KLM-Cityhopper-Flug 433 vom Amsterdamer Flughafen Shiphol ins walisische Cardiff. Um den Passagieren eine ruhige Fahrt ... That is a repeat of the 2 engine propellor plane case I mentioned: Amsterdam Cardiff 20.03.2023 - Montag  00:15 On monday the next one: Mayday Dokureihe, CDN 2019 Staffel: 19 / Folge: 9 Laufzeit: 35 Minuten Original-Titel: Mayday: Air Disaster Mit: Jonathan Aris, John Elios, Juan Carlos Velis, John Tokatlidis, Jorge Molina, Alexandra Castillo Regie: Mark Mainguy Der brasilianische Fußball-Erstligist Chapecoense erreichte 2016 völlig überraschend das Finale des Copa Sudaméricana. Doch auf dem Weg zum Spiel ... It is also on 'Welt' (different schedule but I can receive that). kingofsat.net is my satellite help: https://en.kingofsat.net/find.php?&lim=20&standard=All&ordre=freq&question=NATIONAL-GEOGRAPHIC&filtre=no&aff=zap should be able to receive it on hotbird and astra and even badr5 28 East steerable dish here Thanks
Reply by ●March 19, 20232023-03-19
søndag den 19. marts 2023 kl. 08.00.28 UTC+1 skrev Jan Panteltje:> On a sunny day (Sat, 18 Mar 2023 13:38:44 -0700 (PDT)) it happened Lasse > Langwadt Christensen <lang...@fonz.dk> wrote in > <9628b72f-aa02-40d2...@googlegroups.com>: > >lørdag den 18. marts 2023 kl. 20.30.07 UTC+1 skrev Jan Panteltje: > >> On a sunny day (Sat, 18 Mar 2023 10:28:46 -0700) it happened John Larkin= > > > >> <jla...@highlandSNIPMEtechnology.com> wrote in > >> <kisb1ipbum7dulpqh...@4ax.com>: > >> >On Sat, 18 Mar 2023 15:46:03 GMT, Jan Panteltje <al...@comet.invalid> > >> >wrote: > >> >>I have no idea what a FADEC is or what its internals are > >> >>so I looked it up: > >> >> https://en.wikipedia.org/wiki/FADEC > >> >> > >> >>Now I will stop flying!!!! > >> > > >> >Each FADEC is redundant, and gets power from both the airframe DC > >> >supply and from a dual alternator on its engine. Thet are very > >> >reliable. Most engine problems are mechanical or fuel related. Birds > >> >are bad in jet engines. > >> > > >> >We sell alternator simulators that are used to test FADECs, which > >> >furtunately people buy two at a time. It's kind of interesting, since > >> >a PM alternator is basically a current source and the FADECs regulate > >> >by shorting them. Our rev A box tended to blow up. > >> > > >> > > >> >Some small planes have full-plane parachutes. They land hard but > >> >survivably. > >> >>Engine on fire, we circled and dumped fuel, then landed safely on one e= > >ngine. > >> > > >> >Planes can fly on one engine, as long as the failed one doesn't toss > >> >blades and tear a wing off or something like that. They have > >> >"containment" that usually works. Engines are tested to destruction to= > > > >> >make sure the blades stay inside. > >> There is a series on German satellite TV about plane crashes that happene= > >d and they go into all the details > >> and follow the guys evaluating what's left.. to find the cause. > > > >"Aircrash investigation" I'd guess, they are not bad but there's a few yout= > >ube channels* > >with actual pilots going through the accident reports, watching those make = > >you realise > >the TV shows are often far from accurate > No, not Aircrash investigation, forgot he name, German channel, think it was called 'Mayday' or something? > Will let you know when I hit it again (hundreds of channels here) > >*to mention a few, Mentour Pilot and blancolirio > > > >> There is a lot that can go wrong, often pilot error like the one I follow= > >ed > >> last week that crashed in a field near Schiphol airport, > >> pilot had one engine throttled down.. (propeller 2 engine plane) without = > >knowing it (he did it himself) > >> so when steering towards the runway the plane tilted one way and he lost = > >control.. > > > >There was one similar in Nepal, probably caused by the first officer pullin= > >g the wrong handle feathering the engines > >instead of lowering the flaps, like because he would normally be flying in = > >the left seat as a captain, but on this flight > >he was an instructor so he was in the right seat... > Checklist are interesting too, I have a checklist for some thing I do, > I went through it and sure enough one day I found out I had missed something... > > There was this airplane .. they went through the takeoff checklist but were interrupted > by a stewardess making an appointment for the evening with one of the pilots (voice recorder was recovered) > so they forgot to set the flaps for takeoff. > Hundreds died, crashed at the end of the runway, ball of fire (full of fuel). > > You want a computer there saying: "Hey dummy, set your flaps or I will do it for you !!" > Procedure is: Nobody allowed in the cockpit during prepare for takeoff, but human relations...if it's the one I'm thinking about the plane does have an alarm for not being properly configured for takeoff but there have been at least one crash or near where it didn't sound, possible because some pilots had a habit of pulling the fuse for that alarm because it would trigger when taxiing a little to fast
Reply by ●March 19, 20232023-03-19
On Saturday, March 18, 2023 at 6:57:33 PM UTC-4, John Larkin wrote:> On Sat, 18 Mar 2023 15:23:20 -0700 (PDT), Fred Bloggs > <bloggs.fred...@gmail.com> wrote: > >On Saturday, March 18, 2023 at 1:48:27?PM UTC-4, John Larkin wrote: > >> On Sat, 18 Mar 2023 07:44:01 -0700 (PDT), Fred Bloggs > >> <bloggs.fred...@gmail.com> wrote: > >> >On Friday, March 17, 2023 at 11:21:37?AM UTC-4, John Larkin wrote: > >> >> I've been asked to design an 8-channel dummy load board. It's not very > >> >> challenging but somebody's got to do it. It will be used to simulate > >> >> small loads like solenoids or relays or torque motors. It needs some > >> >> inductance too, because the drivers often PWM. Maybe 10 or so watts > >> >> per channel. > >> >> > >> >> I could do this electronically, but it would a lot easier and more > >> >> rugged if I use wirewound resistors. I was thinking of making a > >> >> conductance DAC, namely resistors R 2R 4R etc switched in parallel > >> >> across the inputs with an SSR per resistor. > >> >> > >> >> But there is a history of clever load banks. When I was an EE student > >> >> at Tulane, two semisters of Electrical Machinery (with lab) was > >> >> mandatory. It was a pain but I learned a lot. We had a big load bank > >> >> in the machinery lab, a string of giant series resistors with a > >> >> 3-position knife switch at each node. That made me think about using > >> >> series-parallel combinations to hit some target value. > >> >> > >> >> https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1 > >> >> > >> >> The upper pic is the ancient Tulane load bank as I remember it. > >> >> > >> >> I was thinking about the lower circuit for my gadget. I could use > >> >> wirewould resistors and kink the leads to space them maybe 3/4 inch > >> >> above my PCB, in the air stream. The higher value resistors might be > >> >> 2512 surface mounts. > >> >> > >> >> I think there is a tool to bend and kink resistor leads. Or we could > >> >> send a bunch out to a service maybe. > >> > > >> >It's called standoff lead forming. There are bunches different tools, but it looks like the handheld plier types are more universal. Low cost too. > >> > > >> >https://forum.digikey.com/t/bending-and-forming-leads/8184 > >> > > >> >How is any of this a puzzle? > >> A good design is most always a puzzle, which makes design interesting. > >> > >> One issue is, how much power can you dissipate in 4 square inches of > >> PC board with some given air flow? Big heat sink with mosfets? Small > >> CPU cooler? I'm thinking of using axial-lead wirewound resistors > >> spaced off the board enough that the leads have enough thermal > >> resistance to not scorch the board when the resistor gets very hot. > > > >Keep in mind people tend to lose respect for a product that smells like it's burning. You should be determining the threshold case temperature at which outgassing becomes noticeable, via olfactory sensing, and see if reducing temps by half, with proper derating for ambient, does anything for you. > Vitreous enameled resistors would be best for not outgassing. Silicone > or whatever would be worse. > > Wirewound resistors tend to run at crazy temps, like 270C, at full > power. I wouldn't want to scorch the PCB. > > There are some nice DPAK power resistors that could be clamp mounted > on heat sinks, which would provide a lot of surface area. > > There are also TO-220 power resistors, which could be attached to heat > sinks with nuts and bolts.Setting off smoke detectors would be the absolute worst.
Reply by ●March 19, 20232023-03-19
On Sat, 18 Mar 2023 08:11:29 -0700, John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:>On Sat, 18 Mar 2023 07:13:33 -0400, legg <legg@nospam.magma.ca> wrote: > >>On Fri, 17 Mar 2023 14:41:51 -0700, John Larkin >><jlarkin@highlandSNIPMEtechnology.com> wrote: >> >>>On Fri, 17 Mar 2023 17:14:59 -0400, legg <legg@nospam.magma.ca> wrote: >>> >>>>On Fri, 17 Mar 2023 08:21:23 -0700, John Larkin >>>><jlarkin@highlandSNIPMEtechnology.com> wrote: >>>> >>>>> >>>>>I've been asked to design an 8-channel dummy load board. It's not very >>>>>challenging but somebody's got to do it. It will be used to simulate >>>>>small loads like solenoids or relays or torque motors. It needs some >>>>>inductance too, because the drivers often PWM. Maybe 10 or so watts >>>>>per channel. >>>>> >>>>>I could do this electronically, but it would a lot easier and more >>>>>rugged if I use wirewound resistors. I was thinking of making a >>>>>conductance DAC, namely resistors R 2R 4R etc switched in parallel >>>>>across the inputs with an SSR per resistor. >>>>> >>>>>But there is a history of clever load banks. When I was an EE student >>>>>at Tulane, two semisters of Electrical Machinery (with lab) was >>>>>mandatory. It was a pain but I learned a lot. We had a big load bank >>>>>in the machinery lab, a string of giant series resistors with a >>>>>3-position knife switch at each node. That made me think about using >>>>>series-parallel combinations to hit some target value. >>>>> >>>>>https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1 >>>>> >>>>>The upper pic is the ancient Tulane load bank as I remember it. >>>>> >>>>>I was thinking about the lower circuit for my gadget. I could use >>>>>wirewould resistors and kink the leads to space them maybe 3/4 inch >>>>>above my PCB, in the air stream. The higher value resistors might be >>>>>2512 surface mounts. >>>>> >>>>>I think there is a tool to bend and kink resistor leads. Or we could >>>>>send a bunch out to a service maybe. >>>>> >>>>> >>>>> >>>> >>>>Active I=kV with a delay would give you an inductance. >>> >>> >>>A real inductor stores energy, which a synthesized inductor usually >>>doesn't. >>> >>>Stored energy pumps current into flyback diodes or equivalent. >>> >>>> >>>>Does the driver really care? >>> >>>It certainly might. >>> >>>> >>>>Where'd the word 'dummy' originate in the spec? If it reflects >>>>the attitude of the buyer, I'd say 'No Bid'. I've had it with >>>>idiots like that. >>> >>>Oh, they are just a biggish aerospace company. >>> >>>No bid? Is that a good business model? >>> >>>> >>>>RL >>> >>>https://en.wikipedia.org/wiki/Dummy_load >>> >> >>The minute you considered variable, multicase and >>especially inductive, it ceased to be idiot-proof. >> >>Use sockets and real loads, if it's that important. >> >>RL > >The customer has an existing design where they select and solder a >selected set of resistors and inductors per channel, unique to each >unit. We don't want to be in the business of doing that for them, with >every unit having its own dash number and BOM and test limits. > >I'd like to design a programmable dummy load board that we can >manufacture and stock and ship when we get an order. > >It's looking like a straight conductance DAC is the way to go: >parallel N resistors (R, 2R, etc) with a solid-state switch per. Given >a binary control code K, net conductance is proportional to K so >resistance goes as 1/K. N=5 maybe; we're not simulating RTDs. That's >nice and simple and adds an open-circuit case for free. Two more SSRs >can add short and ground fault cases, selling points. > >I like to add little goodies to products when it's not hard and >doesn't interfere with the base function. You never know if something >will appeal to someone and tip a basically emotional buy decision, as >in "That thingie might be useful some day, let's buy theirs." > >Colors matter too. >Overv time you've talked about all sorts of low voltage loads that swotted the heat in mosfets and a heatsink. Doesn't that have a placxe here? RL
Reply by ●March 19, 20232023-03-19
On Sun, 19 Mar 2023 07:00:19 GMT, Jan Panteltje <alien@comet.invalid> wrote:>On a sunny day (Sat, 18 Mar 2023 13:38:44 -0700 (PDT)) it happened Lasse >Langwadt Christensen <langwadt@fonz.dk> wrote in ><9628b72f-aa02-40d2-b1e4-c5087e2c7083n@googlegroups.com>: > >>lørdag den 18. marts 2023 kl. 20.30.07 UTC+1 skrev Jan Panteltje: >>> On a sunny day (Sat, 18 Mar 2023 10:28:46 -0700) it happened John Larkin= >> >>> <jla...@highlandSNIPMEtechnology.com> wrote in >>> <kisb1ipbum7dulpqh...@4ax.com>: >>> >On Sat, 18 Mar 2023 15:46:03 GMT, Jan Panteltje <al...@comet.invalid> >>> >wrote: >>> >>I have no idea what a FADEC is or what its internals are >>> >>so I looked it up: >>> >> https://en.wikipedia.org/wiki/FADEC >>> >> >>> >>Now I will stop flying!!!! >>> > >>> >Each FADEC is redundant, and gets power from both the airframe DC >>> >supply and from a dual alternator on its engine. Thet are very >>> >reliable. Most engine problems are mechanical or fuel related. Birds >>> >are bad in jet engines. >>> > >>> >We sell alternator simulators that are used to test FADECs, which >>> >furtunately people buy two at a time. It's kind of interesting, since >>> >a PM alternator is basically a current source and the FADECs regulate >>> >by shorting them. Our rev A box tended to blow up. >>> > >>> > >>> >Some small planes have full-plane parachutes. They land hard but >>> >survivably. >>> >>Engine on fire, we circled and dumped fuel, then landed safely on one e= >>ngine. >>> > >>> >Planes can fly on one engine, as long as the failed one doesn't toss >>> >blades and tear a wing off or something like that. They have >>> >"containment" that usually works. Engines are tested to destruction to= >> >>> >make sure the blades stay inside. >>> There is a series on German satellite TV about plane crashes that happene= >>d and they go into all the details >>> and follow the guys evaluating what's left.. to find the cause. >> >>"Aircrash investigation" I'd guess, they are not bad but there's a few yout= >>ube channels* >>with actual pilots going through the accident reports, watching those make = >>you realise >>the TV shows are often far from accurate > >No, not Aircrash investigation, forgot he name, German channel, think it was called 'Mayday' or something? >Will let you know when I hit it again (hundreds of channels here) > > >>*to mention a few, Mentour Pilot and blancolirio >> >>> There is a lot that can go wrong, often pilot error like the one I follow= >>ed >>> last week that crashed in a field near Schiphol airport, >>> pilot had one engine throttled down.. (propeller 2 engine plane) without = >>knowing it (he did it himself) >>> so when steering towards the runway the plane tilted one way and he lost = >>control.. >> >>There was one similar in Nepal, probably caused by the first officer pullin= >>g the wrong handle feathering the engines >>instead of lowering the flaps, like because he would normally be flying in = >>the left seat as a captain, but on this flight >>he was an instructor so he was in the right seat... > >Checklist are interesting too, I have a checklist for some thing I do, >I went through it and sure enough one day I found out I had missed something...We have a PCB release checklist. It's several pages.
Reply by ●March 19, 20232023-03-19
On Sun, 19 Mar 2023 09:55:06 -0400, legg <legg@nospam.magma.ca> wrote:>On Sat, 18 Mar 2023 08:11:29 -0700, John Larkin ><jlarkin@highlandSNIPMEtechnology.com> wrote: > >>On Sat, 18 Mar 2023 07:13:33 -0400, legg <legg@nospam.magma.ca> wrote: >> >>>On Fri, 17 Mar 2023 14:41:51 -0700, John Larkin >>><jlarkin@highlandSNIPMEtechnology.com> wrote: >>> >>>>On Fri, 17 Mar 2023 17:14:59 -0400, legg <legg@nospam.magma.ca> wrote: >>>> >>>>>On Fri, 17 Mar 2023 08:21:23 -0700, John Larkin >>>>><jlarkin@highlandSNIPMEtechnology.com> wrote: >>>>> >>>>>> >>>>>>I've been asked to design an 8-channel dummy load board. It's not very >>>>>>challenging but somebody's got to do it. It will be used to simulate >>>>>>small loads like solenoids or relays or torque motors. It needs some >>>>>>inductance too, because the drivers often PWM. Maybe 10 or so watts >>>>>>per channel. >>>>>> >>>>>>I could do this electronically, but it would a lot easier and more >>>>>>rugged if I use wirewound resistors. I was thinking of making a >>>>>>conductance DAC, namely resistors R 2R 4R etc switched in parallel >>>>>>across the inputs with an SSR per resistor. >>>>>> >>>>>>But there is a history of clever load banks. When I was an EE student >>>>>>at Tulane, two semisters of Electrical Machinery (with lab) was >>>>>>mandatory. It was a pain but I learned a lot. We had a big load bank >>>>>>in the machinery lab, a string of giant series resistors with a >>>>>>3-position knife switch at each node. That made me think about using >>>>>>series-parallel combinations to hit some target value. >>>>>> >>>>>>https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1 >>>>>> >>>>>>The upper pic is the ancient Tulane load bank as I remember it. >>>>>> >>>>>>I was thinking about the lower circuit for my gadget. I could use >>>>>>wirewould resistors and kink the leads to space them maybe 3/4 inch >>>>>>above my PCB, in the air stream. The higher value resistors might be >>>>>>2512 surface mounts. >>>>>> >>>>>>I think there is a tool to bend and kink resistor leads. Or we could >>>>>>send a bunch out to a service maybe. >>>>>> >>>>>> >>>>>> >>>>> >>>>>Active I=kV with a delay would give you an inductance. >>>> >>>> >>>>A real inductor stores energy, which a synthesized inductor usually >>>>doesn't. >>>> >>>>Stored energy pumps current into flyback diodes or equivalent. >>>> >>>>> >>>>>Does the driver really care? >>>> >>>>It certainly might. >>>> >>>>> >>>>>Where'd the word 'dummy' originate in the spec? If it reflects >>>>>the attitude of the buyer, I'd say 'No Bid'. I've had it with >>>>>idiots like that. >>>> >>>>Oh, they are just a biggish aerospace company. >>>> >>>>No bid? Is that a good business model? >>>> >>>>> >>>>>RL >>>> >>>>https://en.wikipedia.org/wiki/Dummy_load >>>> >>> >>>The minute you considered variable, multicase and >>>especially inductive, it ceased to be idiot-proof. >>> >>>Use sockets and real loads, if it's that important. >>> >>>RL >> >>The customer has an existing design where they select and solder a >>selected set of resistors and inductors per channel, unique to each >>unit. We don't want to be in the business of doing that for them, with >>every unit having its own dash number and BOM and test limits. >> >>I'd like to design a programmable dummy load board that we can >>manufacture and stock and ship when we get an order. >> >>It's looking like a straight conductance DAC is the way to go: >>parallel N resistors (R, 2R, etc) with a solid-state switch per. Given >>a binary control code K, net conductance is proportional to K so >>resistance goes as 1/K. N=5 maybe; we're not simulating RTDs. That's >>nice and simple and adds an open-circuit case for free. Two more SSRs >>can add short and ground fault cases, selling points. >> >>I like to add little goodies to products when it's not hard and >>doesn't interfere with the base function. You never know if something >>will appeal to someone and tip a basically emotional buy decision, as >>in "That thingie might be useful some day, let's buy theirs." >> >>Colors matter too. >> > >Overv time you've talked about all sorts of low voltage loads >that swotted the heat in mosfets and a heatsink. > >Doesn't that have a placxe here? > >RLI'm planning a separate big single-channel electronic load board that uses mosfets on a CPU cooler and can do programmed constant-current and constant-resistance ac or dc over a huge range. That topology would be complex for a small 8-channel load that has onboard inductors. The mosfet thing needs isolated fast DACs and ADCs per channel and closed loop control in an FPGA. Resistors and SSR are sure easy. A CPU cooler is a possibility on the 8-channel board. A K199 type would fit on my board and can easily dissipate 150 watts. The bottom copper plate would need to be tapped to screw down a bunch of (expensive, unavailable) TO-220 resistors or something. High thermal conductivity (ie, fairly pure) copper is gummy and a nuisance to tap, but it can be done. That would roughly double the cost of the cooler. At least TO-220 resistors don't need insulators like mosfets would.
Reply by ●March 19, 20232023-03-19
On Sat, 18 Mar 2023 10:54:12 -0700 (PDT), whit3rd <whit3rd@gmail.com> wrote:>On Saturday, March 18, 2023 at 8:20:02?AM UTC-7, John Larkin wrote: >> On Sat, 18 Mar 2023 07:08:29 -0400, legg <le...@nospam.magma.ca> wrote: > >> >A dummy load is usually invariable and requires no >> >operator adjustment. >> Why? A programmable dummy load can be very useful. >> > >> >A 'dummy' can screw up even simple switches or rheostats. > >> They could wire anything wrong. > >Yeah, and... for an inspection-quality load, you might want a barcode >for each of a dozen variants. At inspection time, if the right barcode isn't >scanned, the inspection is invalid.If I suggest a product with even three variants my boss will attack me. Production hates that. Hence programmability. Customers would like programmability too.> >Adjustable boxes aren't good "standard" loads for a formal inspection process, IMHO. >At a minimum, you'd want a calibration date, and complete record of the settings, printed onto an >attachable sticker label, for the final report. > >How does one calibrate eight different adjustable loads, each having dozens of settings?I wouldn't calibrate the resistors; just specify their tolerance. We would calibrate the ADCs, one per channel to report actual voltage and current. I don't think that something like 5% tolerance would be a problem for people simulating solenoids or motors. The measurements could be calibrated to 1%. There are some very cool 2 and 3-channel isolated ADCs intended for use in electric meters. Cheap but not super fast; good for average measurements but not for closing fast control loops.
