• The Venerable 741

    From Cursitor Doom@21:1/5 to All on Sun Nov 3 18:07:35 2024
    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to All on Sun Nov 3 10:33:04 2024
    On Sun, 03 Nov 2024 18:07:35 +0000, Cursitor Doom <cd@notformail.com>
    wrote:

    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I can't think of one. The design is 56 years old. It has its own
    Wikipedia page.

    There are faster, cheaper, lower noise, lower bias current/offset RRIO
    amps around these days.

    I remember the day when, still a kid in college, I decided to replace
    LM709s with LM741s in a control system. The 741s were more expensive
    (the cost of a pretty good lunch) but didn't need external
    compensation parts or front-end-zener protection, and current limited.

    The early 741s had bad popcorn noise, but I'd expect that to be better
    now.

    My default gumdrop amp is OPA197 now, in SOT23. It makes a good
    comparator too. There are cheaper parts if you can tolerate low supply voltages.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Edward Rawde@21:1/5 to Cursitor Doom on Sun Nov 3 14:09:11 2024
    "Cursitor Doom" <cd@notformail.com> wrote in message news:3refijt75rq65i54haujbpvgin9n4o0n0v@4ax.com...
    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    They will work fine as compatators but a TL081 won't.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to john larkin on Sun Nov 3 19:14:54 2024
    john larkin <JL@gct.com> wrote:
    On Sun, 03 Nov 2024 18:07:35 +0000, Cursitor Doom <cd@notformail.com>
    wrote:

    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I can't think of one. The design is 56 years old. It has its own
    Wikipedia page.

    There are faster, cheaper, lower noise, lower bias current/offset RRIO
    amps around these days.

    I remember the day when, still a kid in college, I decided to replace
    LM709s with LM741s in a control system. The 741s were more expensive
    (the cost of a pretty good lunch) but didn't need external
    compensation parts or front-end-zener protection, and current limited.

    The early 741s had bad popcorn noise, but I'd expect that to be better
    now.

    My default gumdrop amp is OPA197 now, in SOT23. It makes a good
    comparator too. There are cheaper parts if you can tolerate low supply voltages.



    LM358s are still useful, though. I use them in things like bias loops,
    where their limited speed and fairly poor input accuracy don’t matter.

    In our licensing conversations, pointing out that we’re saving more on the BOM than the royalty costs is a pretty persuasive argument, entirely aside
    from the improved performance.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Sun Nov 3 11:34:43 2024
    On Sun, 3 Nov 2024 19:14:54 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    john larkin <JL@gct.com> wrote:
    On Sun, 03 Nov 2024 18:07:35 +0000, Cursitor Doom <cd@notformail.com>
    wrote:

    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I can't think of one. The design is 56 years old. It has its own
    Wikipedia page.

    There are faster, cheaper, lower noise, lower bias current/offset RRIO
    amps around these days.

    I remember the day when, still a kid in college, I decided to replace
    LM709s with LM741s in a control system. The 741s were more expensive
    (the cost of a pretty good lunch) but didn't need external
    compensation parts or front-end-zener protection, and current limited.

    The early 741s had bad popcorn noise, but I'd expect that to be better
    now.

    My default gumdrop amp is OPA197 now, in SOT23. It makes a good
    comparator too. There are cheaper parts if you can tolerate low supply
    voltages.



    LM358s are still useful, though. I use them in things like bias loops,
    where their limited speed and fairly poor input accuracy don’t matter.

    In our licensing conversations, pointing out that we’re saving more on the >BOM than the royalty costs is a pretty persuasive argument, entirely aside >from the improved performance.

    Cheers

    Phil Hobbs

    358 is not bad, a dual opamp for 10 cents, but most have some shared
    current sources that can make sections interact. And weird behavior if
    any input goes slightly below ground.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to john larkin on Sun Nov 3 20:14:04 2024
    john larkin <JL@gct.com> wrote:
    On Sun, 3 Nov 2024 19:14:54 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    john larkin <JL@gct.com> wrote:
    On Sun, 03 Nov 2024 18:07:35 +0000, Cursitor Doom <cd@notformail.com>
    wrote:

    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I can't think of one. The design is 56 years old. It has its own
    Wikipedia page.

    There are faster, cheaper, lower noise, lower bias current/offset RRIO
    amps around these days.

    I remember the day when, still a kid in college, I decided to replace
    LM709s with LM741s in a control system. The 741s were more expensive
    (the cost of a pretty good lunch) but didn't need external
    compensation parts or front-end-zener protection, and current limited.

    The early 741s had bad popcorn noise, but I'd expect that to be better
    now.

    My default gumdrop amp is OPA197 now, in SOT23. It makes a good
    comparator too. There are cheaper parts if you can tolerate low supply
    voltages.



    LM358s are still useful, though. I use them in things like bias loops,
    where their limited speed and fairly poor input accuracy donÂ’t matter.

    In our licensing conversations, pointing out that weÂ’re saving more on the >> BOM than the royalty costs is a pretty persuasive argument, entirely aside >> from the improved performance.

    Cheers

    Phil Hobbs

    358 is not bad, a dual opamp for 10 cents, but most have some shared
    current sources that can make sections interact. And weird behavior if
    any input goes slightly below ground.



    AFAICT it was just the original 324 that had the shared current source
    problem. I’ve never run into it in any 358 or 324A version.

    The problem is pretty unsubtle, though. Pulling both (PNP) inputs of any section high enough causes its tail source to saturate, so its beta tanks
    and it sucks all the available drive, turning off the input stages of the
    other 3 sections.

    There are all sorts of Chinese parts on LCSC that are even cheaper and apparently better, but the 358 is a known quantity, which matters a lot.

    Cheers

    Phil Hobbs
    --
    Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From bitrex@21:1/5 to john larkin on Sun Nov 3 17:12:17 2024
    On 11/3/2024 1:33 PM, john larkin wrote:
    On Sun, 03 Nov 2024 18:07:35 +0000, Cursitor Doom <cd@notformail.com>
    wrote:

    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I can't think of one. The design is 56 years old. It has its own
    Wikipedia page.

    There are faster, cheaper, lower noise, lower bias current/offset RRIO
    amps around these days.

    I remember the day when, still a kid in college, I decided to replace
    LM709s with LM741s in a control system. The 741s were more expensive
    (the cost of a pretty good lunch) but didn't need external
    compensation parts or front-end-zener protection, and current limited.

    The early 741s had bad popcorn noise, but I'd expect that to be better
    now.

    My default gumdrop amp is OPA197 now, in SOT23. It makes a good
    comparator too. There are cheaper parts if you can tolerate low supply voltages.



    The TS27L4 is a good low-priced quad for high voltage (16V)
    applications, I still use the TL084 sometimes too

    For low-voltage/low power the OPA4322 has impressive performance for the
    price:

    <https://www.mouser.com/ProductDetail/Texas-Instruments/OPA4322A>

    For audio the NE5532 is still a go-to.

    The LT1723 for voltage feedback and LT1396 for CF are my high-speed jellies

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to Jeroen Belleman on Sun Nov 3 23:17:55 2024
    On 11/3/24 23:10, Jeroen Belleman wrote:
    On 11/3/24 19:07, Cursitor Doom wrote:
    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I've used them in power supply regulators exposed to radiation.
    Being old designs and all-NPN, they're pretty rad-hard.

    Jeroen Belleman

    Blimey, I just checked: It isn't all-NPN! Fortunately
    for me, it still kept working under irradiation...

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to Cursitor Doom on Sun Nov 3 23:10:13 2024
    On 11/3/24 19:07, Cursitor Doom wrote:
    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I've used them in power supply regulators exposed to radiation.
    Being old designs and all-NPN, they're pretty rad-hard.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to jeroen@nospam.please on Sun Nov 3 15:54:35 2024
    On Sun, 3 Nov 2024 23:17:55 +0100, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 11/3/24 23:10, Jeroen Belleman wrote:
    On 11/3/24 19:07, Cursitor Doom wrote:
    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I've used them in power supply regulators exposed to radiation.
    Being old designs and all-NPN, they're pretty rad-hard.

    Jeroen Belleman

    Blimey, I just checked: It isn't all-NPN! Fortunately
    for me, it still kept working under irradiation...

    Jeroen Belleman

    The early integrated PNPs had betas in the single digits, so a bit of
    radiation poisoning was no big deal.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From bitrex@21:1/5 to Jeroen Belleman on Sun Nov 3 22:24:12 2024
    On 11/3/2024 5:17 PM, Jeroen Belleman wrote:
    On 11/3/24 23:10, Jeroen Belleman wrote:
    On 11/3/24 19:07, Cursitor Doom wrote:
    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I've used them in power supply regulators exposed to radiation.
    Being old designs and all-NPN, they're pretty rad-hard.

    Jeroen Belleman

    Blimey, I just checked: It isn't all-NPN! Fortunately
    for me, it still kept working under irradiation...

    Jeroen Belleman

    Have to go back to Jim Thompson's MC1530 era to get that:

    <http://www.elektronikjk.com/elementy_czynne/IC/MC1530-2.pdf>

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to cd@notformail.com on Mon Nov 4 06:23:17 2024
    On a sunny day (Sun, 03 Nov 2024 18:07:35 +0000) it happened Cursitor Doom <cd@notformail.com> wrote in <3refijt75rq65i54haujbpvgin9n4o0n0v@4ax.com>:

    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I still have a 747 in a box somewhere.
    I used it for my audio mixer in a big hall
    and actually got a complement for the sound quality.

    When the nukes fall you may get lucky as the not nano-nano size
    chip may still work so you can use it to listen to
    Bob's .. what was it called?
    raspberrypi: ~ # locate -i dylan | grep -i war /mnt/sda2/audio/other/bob_dylan/freewheeling/03-masters_of_war_320_lame_cbr.mp3 /mnt/sda2/audio/other/bob_dylan/freewheeling/10-talking_world_war_iii_blues_320_lame_cbr.mp3

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to john larkin on Mon Nov 4 11:46:01 2024
    On 11/4/24 00:54, john larkin wrote:
    On Sun, 3 Nov 2024 23:17:55 +0100, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 11/3/24 23:10, Jeroen Belleman wrote:
    On 11/3/24 19:07, Cursitor Doom wrote:
    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I've used them in power supply regulators exposed to radiation.
    Being old designs and all-NPN, they're pretty rad-hard.

    Jeroen Belleman

    Blimey, I just checked: It isn't all-NPN! Fortunately
    for me, it still kept working under irradiation...

    Jeroen Belleman

    The early integrated PNPs had betas in the single digits, so a bit of radiation poisoning was no big deal.


    Non, au contraire, in bipolar transistors, irradiation tends to
    reduce beta at low current. If it's already low to begin with,
    a bit of irradiation will soon make it drop to useless values,
    and the chip stops working.

    My typical example used to be the LM317 as compared to the LM337.
    The latter has (had?) a large lateral PNP which did not survive
    for long (<50Gy). The LM317 just kept going (>1kGy).

    However, chip design changes that do not affect operation under
    normal circumstances can radically change radiation resistance.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Liz Tuddenham@21:1/5 to Jan Panteltje on Mon Nov 4 10:49:55 2024
    Jan Panteltje <alien@comet.invalid> wrote:

    [...]
    I still have a 747 in a box somewhere.

    How could you loose anything that size?

    --
    ~ Liz Tuddenham ~
    (Remove the ".invalid"s and add ".co.uk" to reply)
    www.poppyrecords.co.uk

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to Liz Tuddenham on Mon Nov 4 11:23:14 2024
    On a sunny day (Mon, 4 Nov 2024 10:49:55 +0000) it happened liz@poppyrecords.invalid.invalid (Liz Tuddenham) wrote in <1r2hvdy.1kbrtmktimep8N%liz@poppyrecords.invalid.invalid>:

    Jan Panteltje <alien@comet.invalid> wrote:

    [...]
    I still have a 747 in a box somewhere.

    How could you loose anything that size?

    Bo[e]ing will explain it to you, they lost 64 so far:
    https://en.wikipedia.org/wiki/Boeing_747_hull_losses

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to bitrex on Mon Nov 4 07:21:18 2024
    On Sun, 3 Nov 2024 22:24:12 -0500, bitrex <user@example.net> wrote:

    On 11/3/2024 5:17 PM, Jeroen Belleman wrote:
    On 11/3/24 23:10, Jeroen Belleman wrote:
    On 11/3/24 19:07, Cursitor Doom wrote:
    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I've used them in power supply regulators exposed to radiation.
    Being old designs and all-NPN, they're pretty rad-hard.

    Jeroen Belleman

    Blimey, I just checked: It isn't all-NPN! Fortunately
    for me, it still kept working under irradiation...

    Jeroen Belleman

    Have to go back to Jim Thompson's MC1530 era to get that:

    <http://www.elektronikjk.com/elementy_czynne/IC/MC1530-2.pdf>

    He probably designed that without Spice.

    The first IC opamp I tried was made by GE. All NPN, with an internal
    zener in the level-shift part. It was amazingly noisy.

    I designed some little baby-board opamps, all TO-92 transistors and
    folded-over axial parts. By selecting some resistors we got sub 1 mV
    offset and under 1 uV/degC, but it was tedious.

    I still have some Philbrick opamps that I found at a flea market.

    https://www.dropbox.com/scl/fi/tujdcjpvv7m4b2yo8w751/Philbricks.jpg?rlkey=19ivv2tgqmqiy9ci92lgysrz7&raw=1

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to Liz Tuddenham on Mon Nov 4 07:27:56 2024
    On Mon, 4 Nov 2024 10:49:55 +0000, liz@poppyrecords.invalid.invalid
    (Liz Tuddenham) wrote:

    Jan Panteltje <alien@comet.invalid> wrote:

    [...]
    I still have a 747 in a box somewhere.

    How could you loose anything that size?

    I visited a guy in repair facility near the local airport. He said
    "Let me show you my repair shop." It had a somewhat disassembled 747
    inside with room to spare.

    They have a setup for testing jet engines at full power too.

    We provided him some electronics for testing APUs, which are prtetty
    dinky gadgets.

    In the life of an airplane, more is spent on maintanance than the
    plane cost. So the maintanance is an interesting market.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From bitrex@21:1/5 to john larkin on Mon Nov 4 14:11:05 2024
    On 11/4/2024 10:21 AM, john larkin wrote:
    On Sun, 3 Nov 2024 22:24:12 -0500, bitrex <user@example.net> wrote:

    On 11/3/2024 5:17 PM, Jeroen Belleman wrote:
    On 11/3/24 23:10, Jeroen Belleman wrote:
    On 11/3/24 19:07, Cursitor Doom wrote:
    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?

    I've used them in power supply regulators exposed to radiation.
    Being old designs and all-NPN, they're pretty rad-hard.

    Jeroen Belleman

    Blimey, I just checked: It isn't all-NPN! Fortunately
    for me, it still kept working under irradiation...

    Jeroen Belleman

    Have to go back to Jim Thompson's MC1530 era to get that:

    <http://www.elektronikjk.com/elementy_czynne/IC/MC1530-2.pdf>

    He probably designed that without Spice.

    The first IC opamp I tried was made by GE. All NPN, with an internal
    zener in the level-shift part. It was amazingly noisy.


    The "natural" CMRR and PSRR of a diff pair stinks without active loads,
    at least on one of the rails; Thompson had to use tricks to get around
    that to keep the output sitting at zero when the inputs were equal

    I designed some little baby-board opamps, all TO-92 transistors and folded-over axial parts. By selecting some resistors we got sub 1 mV
    offset and under 1 uV/degC, but it was tedious.

    I still have some Philbrick opamps that I found at a flea market.

    https://www.dropbox.com/scl/fi/tujdcjpvv7m4b2yo8w751/Philbricks.jpg?rlkey=19ivv2tgqmqiy9ci92lgysrz7&raw=1


    Are those the radioactive ones?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to bitrex on Mon Nov 4 11:34:29 2024
    On Mon, 4 Nov 2024 14:11:05 -0500, bitrex <user@example.net> wrote:

    On 11/4/2024 10:21 AM, john larkin wrote:
    On Sun, 3 Nov 2024 22:24:12 -0500, bitrex <user@example.net> wrote:

    On 11/3/2024 5:17 PM, Jeroen Belleman wrote:
    On 11/3/24 23:10, Jeroen Belleman wrote:
    On 11/3/24 19:07, Cursitor Doom wrote:
    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in >>>>>> certain niche applications in 2024?

    I've used them in power supply regulators exposed to radiation.
    Being old designs and all-NPN, they're pretty rad-hard.

    Jeroen Belleman

    Blimey, I just checked: It isn't all-NPN! Fortunately
    for me, it still kept working under irradiation...

    Jeroen Belleman

    Have to go back to Jim Thompson's MC1530 era to get that:

    <http://www.elektronikjk.com/elementy_czynne/IC/MC1530-2.pdf>

    He probably designed that without Spice.

    The first IC opamp I tried was made by GE. All NPN, with an internal
    zener in the level-shift part. It was amazingly noisy.


    The "natural" CMRR and PSRR of a diff pair stinks without active loads,
    at least on one of the rails; Thompson had to use tricks to get around
    that to keep the output sitting at zero when the inputs were equal

    I designed some little baby-board opamps, all TO-92 transistors and
    folded-over axial parts. By selecting some resistors we got sub 1 mV
    offset and under 1 uV/degC, but it was tedious.

    I still have some Philbrick opamps that I found at a flea market.

    https://www.dropbox.com/scl/fi/tujdcjpvv7m4b2yo8w751/Philbricks.jpg?rlkey=19ivv2tgqmqiy9ci92lgysrz7&raw=1


    Are those the radioactive ones?

    No, just 12AX7 dual triodes. The schematic can be found online.

    The old Foothill Flea Market was great. Some old coot would die and
    leave behind a garage of cool stuff and his kids would take it to the
    flea market and practically give it away just to get rid of it.

    The krytrons are radioactive.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From piglet@21:1/5 to Cursitor Doom on Mon Nov 4 23:12:46 2024
    Cursitor Doom <cd@notformail.com> wrote:
    It's been around an awfully long time and there are far better
    alternatives out there. But is there still a case for using them in
    certain niche applications in 2024?


    As recently as 2006 I designed 741s into a product, mainly on their availability and price, I think they were being dumped on the market at the time. Now they are very unattractive.

    My favourite op amp of that era though is the LM301 which has the very
    useful feature of input common mode range up to positive supply rail.

    uA709 was my first but 741 blew them away.

    --
    piglet

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to john larkin on Tue Nov 5 18:20:56 2024
    On Mon, 04 Nov 2024 07:27:56 -0800, john larkin <JL@gct.com> wrote:

    On Mon, 4 Nov 2024 10:49:55 +0000, liz@poppyrecords.invalid.invalid
    (Liz Tuddenham) wrote:

    Jan Panteltje <alien@comet.invalid> wrote:

    [...]
    I still have a 747 in a box somewhere.

    How could you loose anything that size?

    I visited a guy in repair facility near the local airport. He said
    "Let me show you my repair shop." It had a somewhat disassembled 747
    inside with room to spare.

    They have a setup for testing jet engines at full power too.

    We provided him some electronics for testing APUs, which are prtetty
    dinky gadgets.

    They are, aren't they? Amazing things to watch close up spinning into
    life and revving up to god only knows what sort of RPM.
    I have a friend who's seriously into radio-controlled model aircraft.
    They're about 5 feet long and are powered by actual jet engines! Still
    can't get my head around that.


    In the life of an airplane, more is spent on maintanance than the
    plane cost. So the maintanance is an interesting market.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to Cursitor Doom on Wed Nov 6 15:44:44 2024
    On 6/11/2024 5:20 am, Cursitor Doom wrote:
    On Mon, 04 Nov 2024 07:27:56 -0800, john larkin <JL@gct.com> wrote:

    On Mon, 4 Nov 2024 10:49:55 +0000, liz@poppyrecords.invalid.invalid
    (Liz Tuddenham) wrote:

    Jan Panteltje <alien@comet.invalid> wrote:

    [...]
    I still have a 747 in a box somewhere.

    How could you loose anything that size?

    I visited a guy in repair facility near the local airport. He said
    "Let me show you my repair shop." It had a somewhat disassembled 747
    inside with room to spare.

    They have a setup for testing jet engines at full power too.

    We provided him some electronics for testing APUs, which are prtetty
    dinky gadgets.

    They are, aren't they? Amazing things to watch close up spinning into
    life and revving up to god only knows what sort of RPM.
    I have a friend who's seriously into radio-controlled model aircraft.
    They're about 5 feet long and are powered by actual jet engines! Still
    can't get my head around that.

    Back when I was interested in model aircraft as a kid there were model
    jet engines, but they were pulse jets, of the sort used to power the V1 missiles at the end of WW2.

    In the life of an airplane, more is spent on maintanance than the
    plane cost. So the maintenance is an interesting market.

    Even more interesting to people who fly around in planes that have been
    around for a while.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Michael Schwingen@21:1/5 to Bill Sloman on Thu Nov 7 17:07:51 2024
    On 2024-11-06, Bill Sloman <bill.sloman@ieee.org> wrote:
    Back when I was interested in model aircraft as a kid there were model
    jet engines, but they were pulse jets, of the sort used to power the V1 missiles at the end of WW2.

    Real model jet turbines are available for some time now - some in quite
    small form factor. I talked to one guy at a flight show who had one of
    these in a small EPP foam model converted as a jet trainer:

    https://lambert-modellturbinen-onlineshop.de/

    Going a bit larger, it is quite amazing what a good pilot can do:

    https://www.youtube.com/watch?v=EakeG2h-Hws

    And then theres the "insane" class of RC models:

    https://www.youtube.com/watch?v=ee-QvEeKuck https://www.youtube.com/watch?v=nQctVuPWcMc

    cu
    Michael
    --
    Some people have no respect of age unless it is bottled.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to Michael Schwingen on Fri Nov 8 12:52:22 2024
    On 8/11/2024 4:07 am, Michael Schwingen wrote:
    On 2024-11-06, Bill Sloman <bill.sloman@ieee.org> wrote:
    Back when I was interested in model aircraft as a kid there were model
    jet engines, but they were pulse jets, of the sort used to power the V1
    missiles at the end of WW2.

    Real model jet turbines are available for some time now - some in quite
    small form factor. I talked to one guy at a flight show who had one of
    these in a small EPP foam model converted as a jet trainer:

    https://lambert-modellturbinen-onlineshop.de/

    Hideously expensive, as you'd expect.

    I'm amazed that there's a hobby market for them, though it could be a
    spin-off from the drone business.

    <snipped the predictable stuff>

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)