jabl

54 ms·

871.
by jabl 4y ago
I wonder if a rad-hardened SBC would be covered by ITAR like a lot of other space stuff? If so, would probably push the price and amount of paperwork out of reach of private individuals?
872.
by jabl 4y ago
I'm sure NASA has an enormous amount of hard-earned in-house expertise in rad-hardened electronics, hard real-time safety critical software, and related things. But how much of that knowledge is tied specifically to the POWER ISA? Not
873.
by jabl 4y ago
If you look at the page for the gr765 the parent poster linked to, you can see that the customer can choose the gr765 with either SPARC or RISC-V cores. I think you're right that the plan is to transition to RISC-V, given that the SPAR
874.
by jabl 4y ago
Would it actually raise the cost? Yes, a heat pump is more expensive than a gas furnace, but for an all-electric home you save the cost of a gas hookup. Hell, when building new neighborhoods, can save infrastructure costs by not building ou
875.
by jabl 4y ago
To be fair, as opposed to that picture most people don't install their heat pumps on their patios, but rather on the ugly 'service' side of their house where they have, you know, garbage cans, car parking etc.
876.
by jabl 4y ago
Can confirm. Over here 20 years ago you would be laughed out of the room if you suggested to use an air-source heat pump to heat a house. Nowadays they are the norm, and ground source are a minority. It also helps that building insulation s
877.
by jabl 4y ago
IIRC there are heat pumps that provide up to 180C steam, but that's for industrial usage, I haven't seen anything like that for residential usage.
878.
by jabl 4y ago
Sure there are. My father recently replaced his oil boiler with an air-source heat pump (from Mitsubishi). It plugs into the same hot water pipework for the radiators that the oil boiler was connected to, output temperature is around 60C. E
879.
by jabl 4y ago
> 2-stroke aero engines Which 2-stroke aero engines are you thinking of? > get a pass from using leaded fuel since they run for about ten minutes before the lead fouls the plug Huh? Before unleaded automotive gasoline became the norm,
880.
by jabl 4y ago
To handle bufferbloat (too large buffers without queue management causing long latencies) pick a router based on ath9k, ath10k, or mt76 wifi chips. Those are not the most common ones, and might take a slight amount of effort to match what&#
881.
by jabl 4y ago
> So the tolerances might have been tighter on US production lines, but little thought was placed at least in some designs on how to support operations on the planes instead of just building them. (Something that arguably is present toda
882.
by jabl 4y ago
It's kind of an orthogonal issue. Oil is needed in the fuel for two-strokers with crankcase ventilation for lubrication. Lead is needed to boost octane. But your old outboard engine is most likely a very simple low compression engine t
883.
by jabl 4y ago
> But I guess the comment I originally replied to meant non-turbine ICE only? I would guess that yes, otherwise the comment would be pretty outlandish if the poster is predicting the imminent death of turbine powered aircraft.
884.
by jabl 4y ago
I'm not sure. Surface vs. volume is certainly and interesting thing that explains many scaling phenomena, but in this case, those huge radials had huge fins as well (correspondingly huger than fins on smaller engines in order to cool t
885.
by jabl 4y ago
> A) the highest performance aircraft were all liquid cooled Well, how do you define high performance? Judging by speed at least, Tempest Mk II, Sea Fury, Bearcat, and P-47M are among the fastest piston engined planes ever made. > B)
886.
by jabl 4y ago
> Funnily enough from RAS (Reliability, Availability, Serviceabilty) British liquid cooled engines beat American radial engines so hard it wasn't funny. Presumably you mean the Merlin and not, say, the Sabre? :) But anyway, that&#x2
887.
by jabl 4y ago
The Allison was much older than the P-51 airframe, it was used earlier e.g. for the P-39 and P-40. My memory of Mustang history is a bit hazy, but IIRC the Mustang was originally meant to use the Allison and later they switched to the Merli
888.
by jabl 4y ago
I don't think it's that simple. Inline engines have less frontal area, yes, but then you need a radiator which will add back quite a bit of drag. Further, as Kurt Tank demonstrated with the, at the time, revolutionary FW 190, it&#
889.
by jabl 4y ago
> I worry about people who use a word like 'superior' without any dimensions. Well, let me clarify that as "superior in whatever dimensions the designers of those post-WWII piston engined planes considered important".
890.
by jabl 4y ago
As the saying goes, when you have an engine failure in a twin, the remaining engine takes you to the crash site faster. ;)
891.
by jabl 4y ago
Wouldn't surprise me if aviation engines would move to turbines (see TurbAero and Turbotech for turboprops designed for the GA end of the market), and electric for short range. Leaving little if any space for piston engines. Though of
892.
by jabl 4y ago
The Packard Merlin was a license produced version of the Rolls-Royce Merlin, famous for powering the P-51. The Allison, OTOH, was AFAIK an entirely US design.
893.
by jabl 4y ago
> That's survivor bias and sheer production numbers of us bombers To an extent yes, but the US certainly produced liquid cooled aircraft engines as well, like the Allison's and Packard Merlins powering many famous WWII aircraft
894.
by jabl 4y ago
> Agreed, but sadly it's still a niche fuel. ... I think that unless a large number of GA airplanes can run on true automotive gas (which means gasohol now) in the near future, GA is doomed. There are several problems with gasohol o
895.
by jabl 4y ago
Post-WWI aviation engines overwhelmingly have hardened valves (and valve seats) which work fine with unleaded fuel.
896.
by jabl 4y ago
The logical conclusion of that argument is to scale up the turbo, rip out the big chunking reciprocating mass of metal and just inject fuel directly in a can ahead of the turbo. ;) (Oh, and since your gas generator no longer has a prop shaf
897.
by jabl 4y ago
I don't know. If you look at the swan song of big aviation piston engines just before turbines took over (immediate post-WWII era), it was all air-cooled radials. If the WWII experience would have proved liquid cooled engines to be sup
898.
by jabl 4y ago
> I think you'd really like the Aubrey/Maturin books by Patrick O'Brian. Surprising amount of history-of-science in his historical fiction. Oh yes, I've read the entire Aubrey-Maturin series. I loved it! Good catch! ;
899.
by jabl 4y ago
I really loved the Baroque cycle; Is there any other author that writes similar stuff? I've liked other Stephenson novels I've read (Cryptonomicon and Diamond age), but to be honest they haven't been the mind blowing experien
900.
by jabl 4y ago
I think most(?) C++ implementations of std::string use something called a short-string optimization, where the string type is something like struct string { size_t len; union { char* ptr_to_malloced_string; char

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