Youtube hearted comments of Keit Hammleter (@keithammleter3824).

  1. Kurtis, any time you feel like giving us an extended explanation like you did for air-arc, go for it. This video was the best use of my learning time for a week.
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  2. Expensive to trim with oxy-acet. They paint over a lot of rust - that's a bit slack. Bumper bar shown at the end already has a small dent in it.
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  3. What the heck did they weld that small tool post on the side of the main tool post for? It achieves nothing that some spacers would do, and adds extra probability of chattering, which is what is happening. At 9:06, Allen key left in tool mount screw while running - dangerous.
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  4. Another important factor: in the 1920's, poppet exhaust valves set a limit on engine performance because doing anything to increase power output for a given cylinder size led to exhaust valves being overheated and burning out. Sleeve valves don't have this problem and experts including Harry Ricardo promoted sleeve valves as the future. However, in time for WW2 engines such as the Merlin, sodium filled stellite exhaust valves were developed, which had improved heat flow into the cylinder head and withstood higher temperatures anyway. These rendered sleeve valves obsolete virtually overnight.
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  5. I used to drink "orange" Fanta when I was a teenager. I always thought it was just yellow food dye and sugar in water. It certainly had nothing to do with oranges. I am allergic to citrus fruit, especially oranges. If I eat an orange or drink the juice squeezed for oranges, I will wheeze and have some difficulty breathing. I could drink bottles and bottles of Fanta during summer and have no reaction at all.
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  6. That's not a worm gear, it's a straight cut pinion.
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  7. The Marshall Plan had two purposes: 1) the stated aim of helping Europe recover and modernize its factories, and 2) the unstated aim of enabling US factories to offload war surplus production and obsolete material. A Friend of mine (now deceased) worked in the research lab of a major electronics firm. In about 1930 they had purchased a German toolroom lathe to make custom parts for lab investigations. When WW2 ended, officials of the Marshall Plan showed up and inspected what they had. They said the firm qualified for a new American lathe that would be much better. When the new lathe turned up, it was found to be inferior in terms of precision and operation to the old German lathe, so they kept the German lathe in use and converted the American lathe into a wire coil winder.
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  8. Exactly right, although Britain's prestige went down hill also because she wanted Dominions to keep buying British manufactured goods, and those goods by post-war standards were of poor quality and delivered late or never due to strikes. Armaments supplied by Britain to Australian forces in North Africa were of poor quality. For instance, British-made tanks broke down far too much, and would loose their tracks on turns. When the Australians had run out of operable tanks, they got American tanks as replacements. In theory these tanks were inferior - they were lighter and had smaller guns. But Australian crews called the "honeys" because they only broke down if a German gun actually got a direct hit. They didn't loose their tracks in the tightest turns, so they could race in, get a few shots off and mess up a few enemy vehicles, then turn around and clear off quick before the enemy gets himself organised and fires back. I used to know Australian aircrew who first flew British aircraft in the War and then changed to American aircraft. They all said the US planes were easier to fly, more reliable, and much easier to fix when they did go wrong. When a British fighter plane was delivered, in its crates, it took several skilled mechanics a couple of days to get it in flying condition. They could have a crated American fighter flying within an hour, using one trained mechanic assisted by a couple of untrained helpers.
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  9. The USA was slow to use diesel fuel in trucks because they taxed gasoline at a low rate, a lot less than on diesel fuel. Thus their tax regime masked the cost saving in using more efficient diesel engines. It should be noted too that the USA is an extremely conservative, change resistant, country. This shows up in many ways, apart from sticking to gasoline:- sticking to 8-track tapes long after the market died elsewhere; 8-bit s-100 CP/M computers selling long after the world changed to 16-bit DOS computers; and refusing to go metric.
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  10. VisioRacer is quite right - inline engines have more of a problem with crankshaft torsional vibration. It wasn't a problem with the old American inline 8 car engines due to low compression design, and low power output. In the 1930's America, a long engine bay on a car was a status symbol. Post-war, long engine bays were considered ugly, and women drivers found long cars hard to park. So engines had to be shorter - hence V8's, not I8's, post war. An additional minor advantage of V-engines is lower friction. For any given cylinder swept volume, you would expect the power lost in friction would be directly proportional to the number of cylinders. However, for any given cylinder size and number of cylinders, the V-formation has less friction than the inline form due to the staggering of peak loads on each crank throw. For a while. I worked as the engineer for a dealer selling large industrial diesel engines. Over a whole range of an engine series, the cylinder size is always the same. One series we sold gave about 50 kW per cylinder, so if you needed 200 kW, you got an inline 4, if you wanted 300 kW, you got an inline 6, if you needed 400 kW, you got a V8, and if you needed 600 kW, you got a V12. And if you needed 800 kW, you got a V16. The V8 got the same size starter motor as the I4. The V12 got the same size starter motor as the I6. Of course the V16 had two starter motors fitted, each the same size as the one fitted to the V8 and I4. This is not the full picture though - for example the I4 cranked a bit faster that the V8. But the friction loads were close enough to allow starter motor standardization. The V engines needed only slightly larger starting batteries too. So, all up, a V8 is cheaper than an I8 for example.
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  11. There's often something odd about these Pakistani small shop videos. In this case, it's an old guy using giant tinsnips to cut straight lines in steel sheet. The place clearly has more complex machines - so why don't they have a guillotine? Even a simple hand operated guillotine would considerably improve productivity. Door skins are far below normal quality - just a single colour coat of paint on untreated mild steel - no rustproofing of any kind. Finished door skin shown at end has a clearly visible blemish.
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  12. Gee, that design of battery charger goes back to the 1930's, except for the use of 1960's style stud rectifiers instead of selenium. Don't these guys know you can now buy potted silicon bridge rectifiers at much lower cost? It looks like they are cutting up regular passivated steel sheet to make the core laminations instead of using proper transformer-type silicon steel - as far as I know transformer steel is only supplied already punched into laminations, bonded into C-cores or toroids, or supplied in bulk in huge coils. Using regular steel would be a lot cheaper, but the energy efficiency will be low, due to considerable hysteresis and low permitted flux density. Efficiency will be lowered more due to burrs left during their guillotining, which will short the laminations. Normally, laminations are punched first and then passivated, which ensures good inter-lamination insulation. They are grouping the laminations instead of 1:1 interleaving, which is normally regarded as poor practice in the transformer industry, but given the above points, and that it is a high leakage reactance design (desirable in a simple battery charger) it may be a good thing.
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  13. Let's be quite clear about something: Truman was right to sack Macarther. Macarther had lost the plot and wanted to nuke North Korea so as to make it permanently uninhabitable.
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  14.  @singendertanz5075  I might have used a three-bolt mounting, but Kurtis has some experience and he has his mate check out designs in CAD. If it does resonate, its easily fixed with one or 2 internal braces. Let's wait and see how it goes. I'm more concerned he's going to well exceed the safe speed of grinding wheels.
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  15. I once owned a car with "white wall" tires. No part of the tire was white - they were standard black rubber tires. The white part was an added disk of white rubber clamped between the wheel rim and the tire, shaped so that its elasticity holds it against the tire. It was purely a decorative thing. It has no strength. The white on Soviet parade vehicles is also purely decorative for the parade, as with all the white painted stripes on the vehicle bodies. On film of Soviet vehicles deployed in action you don't see any white. There's not much point in painting a vehicle in camouflage olive green/brown if you highlight it with white. The enemy would be laughing. I could accept that coating a tire would protect it against sun damage, but only if you coated the WHOLE tire. If you only coat the sides, that's not going to do much. I question where Matsimus got his information - he seems to have taken it out of context.
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  16. Kurtis, baby spiral flute taps are available from RS Components Pty Ltd in Sydney. M3.5 is catalog number 152-031.
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  17. You most certainly were missed last week. I guessed you were busy with important paying work.
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  18.  @OceanlinerDesigns  That is true, it gives you much more space for cargo or passengers, although an oil fired boiler can be designed to take up a lot less space than the old scotch boilers that were common in the coal days, especially when taking into account you don't need an army of stokers, who need workspace, off duty space, and sleeping space.
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  19. Sergei, contrary to your comment at the end, I found your video interesting, at least to me. I am an Australian, I grew up on my father 's farm. The farm next door was owned by a Ukrainian guy who was a refugee from World War 2. He could barely speak any English - hello, bye, yes, no, how are you was about his limit. His wife had to do the shopping so she spoke English quite a bit better. Him and his wife and kids spoke what I gather was mostly Russian amongst themselves, but since I spent a lot of time with his son and on their farm from a very young age, I picked up a few words - enough to converse with him on simple everyday subjects. He made it very clear that he absolutely HATED Russians. So in the context of the war in Ukraine now I was wondering if inherited hatred was a factor in Ukraine's spirited and deterrmined defence. From your video made before the "Special Military Operation", I gather not - just a typical bit of racial/cultural prejudice existed in recent years.
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  20. At 8:59 while talking about the amount of air going through vs the thrust produced, Warped Perception states "most of the energy comes from the fuel." That's sort of right, as the fuel notionally supplies chemical energy though combustion, but he doesn't say that, and in his context it is misleading and confusing. Jet engines operate stochiomentrically - that is the mass of air consumed must just equal the amount required to completely combust the fuel and no more. For hydrocarbon fuels, the mass of air must be about 15 times the mass of the fuel consumed. (Only the oxygen is used chemically - air is about 80% nitrogen which passes through chemically unchanged. The actual oxygen mass is about 3 times the mass of the fuel.) What produces the net thrust in a jet engine is that combustion raises the volume of air/fuel mix such that the burning gasses can push against a greater area of the forward inside engine surface than the combustion chamber air inlet area. The burning gas pressure in the combustion chamber must be approx equal or a bit less than the incoming air pressure to the chamber as otherwise burning gasses would come out the front. Thus forward thrust is produced as the exhaust orifice, always much larger than the air inlet orifice size, cannot offer much more than surrounding air pressure. Jet engines are most easily understood properly by first considering a ram-jet engine, which has no moving parts. Intake air is compressed by the forward motion forcing the air through a funnel, so reducing the area and raising the pressure. Again, as with a turbojet, the forward part of combustion chamber surface area must be greater than the chamber hole for the incoming air, and is much greater than the exhaust orifice back pressure. Understand all that and you will not only understand that the mass of air is more important than the mass of fuel (both supply the pressure, and there's much more air than fuel), you will also understand that the efficiency of a jet engine (ram or turbo) is proportional to the compression ratio. In World War The British Air Ministry and the Royal Air Force famously took no notice of Frank Whittle and his jet engine, because his design and available materials permitted only a very low compression ratio, and thus they knew the fuel consumption would have to be horrendous without needing to test it. The jet became practical when others (eg at Rolls Royce) redesigned it to have a better compression ratio).
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