Compression ratio is the number that sets fuel economy and power output for internal combustion engines. More is better. Inside the engine, the fuel air mixture lights off at top dead center. The piston goes down, expanding the hot combustion gases, cooling them, and converting the heat energy from the burning fuel into mechanical work. Ideally we would keep the piston moving down, expanding the cylinder volumn until the combustion gases had been cooled down to room temperature, extracting all possible mechanical work from the fuel burn.
In real engines, the piston cannot keep going down forever. The piston gets to bottom dead center. Which is about 4 inches in a typical car engine. At which point the exhaust valve opens and the still blazing hot combustion gases go out the tailpipe. At night, running a short straight exhaust pipe, no muffler, you can see the exhaust gas glowing blue-white. That's a lot of heat energy that didn't get converted into useful work.
Compression ratio is the ratio of cylinder volume with the piston at top dead center (as small as it gets) to the cylinder volume with the piston at bottom dead center (as big as it gets). The higher the compression ratio, the more of the heat energy of the fuel gets converted into mechanical work. Gasoline engines in cars have compression ratios as low as 8:1, 10:1 in good engines like the Cadillac Northstar, and 13:1 in outright racing engines.
Why not use a higher compression ratio and get more efficiency? In gasoline engines we put a combustable fuel air mixture into the cylinder at bottom dead center and compress it as the piston goes up to top dead center. As the mixture is compressed, it gets hotter. When it gets too hot, it catches fire and burns before the piston is at top dead center, and tries to drive the engine backwards. You can hear this happening, it is a pinging noise (knocking) from the engine. Good fuel (high octane rating fuel) will suppress knocking for a while, but there is a limit. Call it 10:1 for a "street" engine.
And this is the benefit of the diesel engine. Diesels have just pure air in the cylinder for the compression stroke. Fuel is injected into the cylinder at top dead center. Diesels cannot knock. Which means that diesels can run compression ratios as high as 20:1. Which is why diesels have better gas mileage than gasoline engines.
Saturday, October 6, 2018
Friday, October 5, 2018
US Senate votes to have a vote on Kavanaugh
Which is plain stalling, Senate style. They should not be voting to take a vote. That is a pure waste of time, and offers senators a way to vote both yes and no to confuse their constituents. Senate ought to just have a vote on confirming Kavanaugh, and have it right now, not tomorrow.
Representatives should represent their districts
The ancient Greeks invented democracy, some 2500 years ago. They did direct democracy, all the citizens gathered in the Agora and voted on such issues as going to war over Corcyra (which kicked off the Peloponnesian War) or the disastrous expedition to conquer Syracuse on Sicily. Direct democracy is great in principle, but it doesn't scale well (you cannot gather all the citizens of the Roman empire together in one place) and is liable to make poor (disastrous) decisions.
The British invented representative democracy with the institution of Parliament. Each member of Parliament represented all the British subjects of his district. We Americans picked up the idea in colonial times. All the thirteen colonies had representative legislatures by the time of the revolution. So long as the representatives are honest, and truly represent their districts it is a fair system. If the chosen representatives fail to vote in accordance with their district's wishes, it is a corrupt system.
I am running for a seat in the New Hampshire senate. Should I be elected, I will vote the way my district wants, and not the way I may want. As a senator, my duty and my honor call for me to truly represent my district, rather than my personal desires.
The British invented representative democracy with the institution of Parliament. Each member of Parliament represented all the British subjects of his district. We Americans picked up the idea in colonial times. All the thirteen colonies had representative legislatures by the time of the revolution. So long as the representatives are honest, and truly represent their districts it is a fair system. If the chosen representatives fail to vote in accordance with their district's wishes, it is a corrupt system.
I am running for a seat in the New Hampshire senate. Should I be elected, I will vote the way my district wants, and not the way I may want. As a senator, my duty and my honor call for me to truly represent my district, rather than my personal desires.
Thursday, October 4, 2018
More features that Detroit should offer
My 2005 Buick has a feature. After dark, it keeps the headlights on long enough for you to reach your front door. At least that's what it is supposed to do. In real life it either turns the headlights off before you even get out of the car, or it leaves them on too long, causing me to stand out in the rain, watching, to make sure the car does actually turn the headlights off before it runs down the battery. They ought to reprogram the computer so that the headlight timeout does not start until the last car door is closed. This way I could take the groceries out of the back seat and still have some light to climb the front steps and find my door key.
Second feature, a fold down back seat. Folded down, you could fit long stuff like skis and two by fours in from the trunk lid and get them all the way inside the car, and close and latch the trunk lid.
Second feature, a fold down back seat. Folded down, you could fit long stuff like skis and two by fours in from the trunk lid and get them all the way inside the car, and close and latch the trunk lid.
Tuesday, October 2, 2018
How the Brits won the Battle of Britain
The time is 1940, early in WWII. The Germans have just crushed the French, now the Third Reich owns all of Western Europe, except Britain. The Brits managed to get the bulk of their army back from Belgium at Dunkirk. They evacuated better than 300,000 men. But they had to abandon all the army's heavy stuff, tanks, artillery, trucks, ammunition, supplies, yuge amounts of stuff. When Operation Dynamo ended, the British army, although back in England, was in no condition to fight.
If Hitler had managed to get even a small army across the channel and onto English soil, he would have owned the place. The Channel is only 20 some miles wide at Dover and Pas de Calais. Trouble is, the Channel is deep enough to float real warships, and the Brits had plenty of them. If the Germans had loaded the troops onto Rhine River barges and attempted a crossing, the British would have steamed up along side with destroyers, and a few rounds would put the river barge and all its troops on the bottom. At this time the Germans had only a hand full warships, less than a tenth of what the Royal Navy had.
Air power, the Luftwaffe, could have countered the Royal Navy. To do this, the Germans had to wipe out the RAF. They could not sink or drive off the Royal Navy when they had Spitfires on their tails. And so, the Luftwaffe attacked all that late summer and early fall of 1940. Both sides had good pilots and good planes, qualitywise it was a draw between them. The Germans had somewhat more aircraft but not a decisive margin.
Fighter units can only generate so many sorties a day. For instance my fighter wing in the Viet Nam war could do about 110 sorties a day from an assigned strength of 90 F105 Thunderchief fighter bombers. We would launch 60 aircraft on the morning strike which got off at first light. They would return around 11 AM. We had until 2 PM to turn as many birds as possible , finish fixing broken birds from yesterday, and put together the afternoon strike of 60 aircraft. I dare say RAF fighter squadrons could do a little better, the sorties being shorted and the aircraft had less high tech stuff to break and demand fixing. (No doppler, no toss bomb computer, no radar, no TACAN, no gyro compass) But I am sure they had a fixed number of sorties they could generate in a day.
The battle winning weapon the Brits had was radar, and a command and control system (the sector centers they were called) that guaranteed that nearly all RAF fighter sorties would engage the enemy. No sorties wasted patrolling, looking for the enemy, few or no sorties wasted when the enemy was not found. Each sortie flow under radar control would find the enemy and score some kills. This gave the RAF the winning edge in the summer of 1940.
If Hitler had managed to get even a small army across the channel and onto English soil, he would have owned the place. The Channel is only 20 some miles wide at Dover and Pas de Calais. Trouble is, the Channel is deep enough to float real warships, and the Brits had plenty of them. If the Germans had loaded the troops onto Rhine River barges and attempted a crossing, the British would have steamed up along side with destroyers, and a few rounds would put the river barge and all its troops on the bottom. At this time the Germans had only a hand full warships, less than a tenth of what the Royal Navy had.
Air power, the Luftwaffe, could have countered the Royal Navy. To do this, the Germans had to wipe out the RAF. They could not sink or drive off the Royal Navy when they had Spitfires on their tails. And so, the Luftwaffe attacked all that late summer and early fall of 1940. Both sides had good pilots and good planes, qualitywise it was a draw between them. The Germans had somewhat more aircraft but not a decisive margin.
Fighter units can only generate so many sorties a day. For instance my fighter wing in the Viet Nam war could do about 110 sorties a day from an assigned strength of 90 F105 Thunderchief fighter bombers. We would launch 60 aircraft on the morning strike which got off at first light. They would return around 11 AM. We had until 2 PM to turn as many birds as possible , finish fixing broken birds from yesterday, and put together the afternoon strike of 60 aircraft. I dare say RAF fighter squadrons could do a little better, the sorties being shorted and the aircraft had less high tech stuff to break and demand fixing. (No doppler, no toss bomb computer, no radar, no TACAN, no gyro compass) But I am sure they had a fixed number of sorties they could generate in a day.
The battle winning weapon the Brits had was radar, and a command and control system (the sector centers they were called) that guaranteed that nearly all RAF fighter sorties would engage the enemy. No sorties wasted patrolling, looking for the enemy, few or no sorties wasted when the enemy was not found. Each sortie flow under radar control would find the enemy and score some kills. This gave the RAF the winning edge in the summer of 1940.
Monday, October 1, 2018
Communism is Different from Socialism.
So said NHPR today. A woman, (I think she was the moderator on the talk show) said repeatedly and with emphasis that Communism was not the same as Socialism. Talking about classical socialism and communism, as was the breed up thru the 1950's, there was little difference. Both parties read their Karl Marx and believed in government ownership of the means of production, so that government could set everyone's wages to the same low level. Eliminate "wage disparity" at a stroke. And set up a command economy where the politbureau sets production targets for everything. And collectivise farming. The only different between Communists and Socialists was how the party would obtain the power to push thru their program. Communists believed in seizing power thru revolution and force of arms. Socialists advocated political action and the ballot box. Once in power there wasn't much difference from the viewpoint of citizens, kulaks, business people, and nearly everybody else.
Today's "democratic socialism" is probably a little different. I doubt that many of them have read their Marx, know much about socialism's history, and their party platform is "more free stuff". None of them talk about how all that free stuff will be paid for. At least very few of them claim to be Communists, the decades long Cold War blackened the name of Communism too much for anyone to claim it today.
Anyhow I am glad that tax payer funded NHPR feels there is a critical and important different between Communism and Socialism.
Today's "democratic socialism" is probably a little different. I doubt that many of them have read their Marx, know much about socialism's history, and their party platform is "more free stuff". None of them talk about how all that free stuff will be paid for. At least very few of them claim to be Communists, the decades long Cold War blackened the name of Communism too much for anyone to claim it today.
Anyhow I am glad that tax payer funded NHPR feels there is a critical and important different between Communism and Socialism.
Can we trust the FBI anymore?
An organization run by James Coomey, with Peter Strvok, Lisa Page, Andy whats-his-face and who knows what other men of questionable judgement in charge. An outfit that stonewalls the US Congress. Can this outfit conduct a reasonable investigation of the hottest potato in DC, the Dr Basely Ford story?
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