Interesting (non musical) YouTube videos.

[andrew Ivimey]

Vogon poetry might just encapsulate the sheer awful pointlessness and stupidity of drag racing.

I'm perfectly happy with Andrew Marvel - no, not the smutty poem but say, for example, The Garden -'....annihilating all that's made to a green thought in a green shade.' That is poetry.

[Nick]

Let me know when you find a human activity that can't be resolved down to "the sheer awful pointlessness and stupidity", its just doing pointless stuff with some degree of excess and a modicum of style. No different to any visual art, or music, still pointless.

[andrew Ivimey]

Ultimately, in the teleological sense, I can't but whatever one does surely some consideration of doing no harm to others without having to get all upset about aesthetics is still valid. The continuum is long but even so.

[shane]

Not sure what the point is, but an interesting exercise:

[pre65]

Not sure what the point is, but an interesting exercise:

Nice to see new ideas being investigated.

[Nick]

Not sure what the point is, but an interesting exercise:

Nice to see new ideas being investigated.

Not sure what new ideas were shown there.

Eddy current:

"The first person to observe eddy currents was François Arago (1786–1853), the 25th Prime Minister of France, who was also a mathematician, physicist and astronomer. In 1824 he observed what has been called rotatory magnetism, and that most conductive bodies could be magnetized; these discoveries were completed and explained by Michael Faraday (1791–1867).

In 1834, Emil Lenz stated Lenz's law, which says that the direction of induced current flow in an object will be such that its magnetic field will oppose the change of magnetic flux that caused the current flow. Eddy currents produce a secondary field that cancels a part of the external field and causes some of the external flux to avoid the conductor.

French physicist Léon Foucault (1819–1868) is credited with having discovered eddy currents. In September 1855, he discovered that the force required for the rotation of a copper disc becomes greater when it is made to rotate with its rim between the poles of a magnet, the disc at the same time becoming heated by the eddy current induced in the metal. The first use of eddy current for non-destructive testing occurred in 1879 when David E. Hughes used the principles to conduct metallurgical sorting tests."

Eddy Current Clutch:

"At Magnetic Technologies Ltd. we have been building custom eddy current clutches since 1984. We are constantly fine tuning and improving our designs. Today, we have hundreds of custom designed units in use. We have eddy current clutches running on every continent. Because of our maintenance and retro-fit programs, we have a chance to see how our clutches perform over time. Most are still in use even after 15+ years of continual service!"

[Mike H]

I knew some of this already, but this adds a few modern updates :

-

Leaving aside the pointlessness, I did find the engineering challenges interesting.

Off the top of my head –

The engine is rebuilt after every run. They are looking for broken bits or bits about to break. It also gets a new clutch every time.

There is no liquid cooling, because there's no point, it's not running for long enough. However it means the blocks and heads are solid and so stronger. After a rebuild they start it and warm it up and make sure it all works OK. Then it does the tyres warming up burn-out bit, then it does the run. Then it's all rebuilt again.

There's so much pressure in the cylinders that the pistons and conrods get shorter with use. A crankshaft can last up to 15 runs, a piston 8 - 12 runs.

The car does 0 - 100 mph in 1 second. The driver is subjected to 4.5 G. At the other end of the track, at 3 seconds, it's about 280 mph. Stopping is more hairy, the deceleration can cause detached retinas. You keep you eyes closed in case your eyeballs want to pop out.

The engine develops 11,000 hp. Two turbo-chargers make 60 psi of boost. Studs pulling out the block is a common issue, even with extra bolts going in at right angles.

When the video was made, nitro cost $47 a US gallon. The fuel is typically a mix of 80% nitro and 20% methanol. However nitro is slow burning, hence the ignition advance is around 60-something degrees.

The fuel tank is connected via a 2.5 inch diameter pipe, as it uses 3 gallons per second. The tank holds 20 gallons and it might have 3 or 4 left after the warm-up and a run. There are 2 magnetos, each running at 44 Amps.

Sometimes what look like blue sparks may be seen flying out of the engine, this is bits of broken porcelain coming off the spark plugs.


And, it's an expensive hobby!

[Max N]

When I was studying, we took a couple of Chinese students to Santa Pod to watch some drag racing. We tried very hard to explain to them what was happening and why it was happening, but I don’t think they got it. They were asking why the government would pay for such vehicles to be developed.

Anyway, leaving aside the pointlessness, if you have never seen top fuellers ‘in the flesh’, you have imho missed one of life’s great spectacles. The immensity of the noise, the shaking of your internal organs, the incredible acceleration. They make F1 cars, even the old normally aspirated ones, seem tame. A day out at the pod is good value, very accessible, you can chat to the mechanics while they re-build the motors. Highly recommended. Such things may not be around for much longer, and I get the reasons for that and agree with them, but I would say ‘see them while you still can’.

[Dave the bass]

The immensity of the noise, the shaking of your internal organs, the incredible acceleration.

Aaah, Hawkwind!

[jack]

Who said cables weren't important - sometimes, just occasionally, you get what you pay for... mainly, I just think the scanning technology that they are using is terrific! Even though they are comparing two different transmission systems - Thunderbolt 4 vs. USB - they both use USB C connectors.

See also: https://www.lumafield.com/article/usb-c ... zon-basics

Completely nuts - two PSUs, a 10-layer PCB, differential drivers and receivers, every signal strand a mini-coax - those scans are amazing.




Every data strand is a tiny coax... Mad!

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[vinylnvalves]

If USB C its has 5amp current capacity too. Be interesting if they did the same on a Shunanya USB cable - those magic processes that covert a 10 dollar cable into a 1000 dollar cable won’t show up

[Nick]

The 5A is only for the PD cables, otherwise I think its 3A.

I think most of the complexity in the cable that Jack pointed to is for the conversion from Thunderbolt to USB. AFAIK, all that should live in other the USB plug in sending/receiving devices.

[jack]

The 5A is only for the PD cables, otherwise I think its 3A.

I think most of the complexity in the cable that Jack pointed to is for the conversion from Thunderbolt to USB. AFAIK, all that should live in other the USB plug in sending/receiving devices.

My sense was that it's all about signal integrity and noise rather than protocol conversion.

[Nick]

The 5A is only for the PD cables, otherwise I think its 3A.

I think most of the complexity in the cable that Jack pointed to is for the conversion from Thunderbolt to USB. AFAIK, all that should live in other the USB plug in sending/receiving devices.

My sense was that it's all about signal integrity and noise rather than protocol conversion.

Maybe, Thunderbird is twice the throughput of USB-3 as its two sets of balanced TX/RX rather than just the four wires in USB-3. So not sure if there is any big difference in integrity on each data lane.

[jack]

Strangely, I spent today battling a signal integrity issue involving a 5mtr USB C 3.0 cable and associated powered hub. Very annoying.