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Aviation’s Largest Piston Engine (2016)

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Re: Aviation’s Largest Piston Engine (2016)

#31

Post by justin66 »

maxxxxx wrote: post #29
justin66 wrote: post #27

Earlier quoted context omitted.

> Cooling at idle can be a big problem for high performance cars. Or any air cooled car ever made. But the reality is that in a lot of designs, idling will test the effectiveness of the cooling system more than driving the car at speed. (Adding power only exacerbates such a problem. The OP completely fails to understand this) It's much less of a problem than it used to be, with lots of cars including electric fans to…

"Or any air cooled car ever made." Are there still any being built? I thought the 911 was the last holdout until they also switched to water cooling. "with lots of cars including electric fans to help out the radiator," I had that fan breaking once in my Miata and temperatures went into the red really quickly in LA rush hour.

They switched the 911 over to water-cooled in the late nineties, yes. Prior to that, Porsche got the idle temp problem somewhat under control using powerful electric fans positioned in front of some of the oil coolers, but there's essentially no reliable way to cool four-valve cylinder heads with a purely air-cooled engine (the 959 used separate water cooling just for the heads), so they decided the whole thing was a performance dead end. The air-cooled 911 Turbo did get up above 400hp with two-valve heads before the change, though.

> I had that fan breaking once in my Miata and temperatures went into the red really quickly in LA rush hour.

No doubt. Once you train yourself to hear that fan, you realize how much the car depends on it.

Re: Aviation’s Largest Piston Engine (2016)

#32

Post by mc32 »

ethelward wrote: post #30
mc32 wrote: post #23

Earlier quoted context omitted.

Rommel, IIRC, was initilly just one of those kids carrying spades as pretend arms (ok exaggerating a bit). People like him were not near a front during the first war. Hirohito’s men were in some conquest wars, but not heavy wars. So I’m not sure this applies.

> Rommel, IIRC, was initilly just one of those kids carrying spades as pretend arms I beg your pardon? IIRC is a poor excuse when a ten seconds Wiki search proves you wrong. He was a frontline lieutenant. https://en.wikipedia.org/wiki/Erwin_Rommel#World_War_I

My bad, you’re right, i was thinking the idle times spent in Dresden.

Re: Aviation’s Largest Piston Engine (2016)

#33

Post by maxxxxx »

justin66 wrote: post #31
maxxxxx wrote: post #29

Earlier quoted context omitted.

"Or any air cooled car ever made." Are there still any being built? I thought the 911 was the last holdout until they also switched to water cooling. "with lots of cars including electric fans to help out the radiator," I had that fan breaking once in my Miata and temperatures went into the red really quickly in LA rush hour.

They switched the 911 over to water-cooled in the late nineties, yes. Prior to that, Porsche got the idle temp problem somewhat under control using powerful electric fans positioned in front of some of the oil coolers, but there's essentially no reliable way to cool four-valve cylinder heads with a purely air-cooled engine (the 959 used separate water cooling just for the heads), so they decided the whole thing was a…

The problem is that they lost the air cooler sound. A long time ago I drove an air cooled 911 on track. It wasn't that crazy powerful (300hp) but the sound was just fantastic.

Re: Aviation’s Largest Piston Engine (2016)

#34

Post by burfog »

funAtParties wrote: post #5

Sometimes I think about aerial bombardment, and what that really meant during that period of conflict. When you think about the effort to concoct the compounds for the air war, and drop them on cities, with no guidance like lasers or anything, and then you look at the sheer tonnage dropped, and how indiscriminate it really was, you wonder how aerial bombardment is at all distinguishable from chemical weapons. It real…

The distinction seems to be based on the level of disability in the survivors. Dead people are not a burden after the war is over, but maimed people are, and a huge part of that is blindness. Old-style chemical weapons tended to blind people. Post-war civilian life doesn't work so well if a significant chunk of the population is blind.

Re: Aviation’s Largest Piston Engine (2016)

#35

Post by justin66 »

maxxxxx wrote: post #33
justin66 wrote: post #31

Earlier quoted context omitted.

They switched the 911 over to water-cooled in the late nineties, yes. Prior to that, Porsche got the idle temp problem somewhat under control using powerful electric fans positioned in front of some of the oil coolers, but there's essentially no reliable way to cool four-valve cylinder heads with a purely air-cooled engine (the 959 used separate water cooling just for the heads), so they decided the whole thing was a…

The problem is that they lost the air cooler sound. A long time ago I drove an air cooled 911 on track. It wasn't that crazy powerful (300hp) but the sound was just fantastic.

They got big and fat, too. The air-cooled cars had wheelbases similar to your Miata, but they were really pretty small compared to the modern Porsche stuff.

The new stuff is technologically stunning, of course.

Re: Aviation’s Largest Piston Engine (2016)

#36

Post by maxxxxx »

justin66 wrote: post #35
maxxxxx wrote: post #33

Earlier quoted context omitted.

The problem is that they lost the air cooler sound. A long time ago I drove an air cooled 911 on track. It wasn't that crazy powerful (300hp) but the sound was just fantastic.

They got big and fat, too. The air-cooled cars had wheelbases similar to your Miata, but they were really pretty small compared to the modern Porsche stuff. The new stuff is technologically stunning, of course.

True. The old 911s were really small. Now everything is way too big, including the Miata. Mine was a 2000 which was already much bigger than the original but the current ones are just way too big. That's not the point of a Miata.

Re: Aviation’s Largest Piston Engine (2016)

#37

Post by justin66 »

maxxxxx wrote: post #36
justin66 wrote: post #35

Earlier quoted context omitted.

They got big and fat, too. The air-cooled cars had wheelbases similar to your Miata, but they were really pretty small compared to the modern Porsche stuff. The new stuff is technologically stunning, of course.

True. The old 911s were really small. Now everything is way too big, including the Miata. Mine was a 2000 which was already much bigger than the original but the current ones are just way too big. That's not the point of a Miata.

It's funny, I actually admire the extent to which Mazda have managed to keep the Miata small. They're still very easy to pick out in a parking lot when viewed from above, even amidst other sports cars.

Is the extra width and weight the Miata has gained over the years down to changing safety standards? I guess on the bright side, in 2019 they're adding a little power.

Re: Aviation’s Largest Piston Engine (2016)

#38

Post by dingaling »

NeedMoreTea wrote: post #24
Gravityloss wrote: post #13

120 liter displacement. 4x9 = 36 cylinders and many valves and sparks plugs in each. As comparison an early generation single spool turbojet has pretty much one moving part. Nowadays there might be two or three spools and moving vanes and a thrust reverser. But aviation would never have been possible for the masses with piston engines.

Avro Lancaster, one of the two most successful heavy bombers of WW2 had 4 27litre V12 merlins, with proven reliability. The Avro Lancastrian was a passenger variant of the Lanc and developed into the large bodied Avro York that had the range to replace a few of the old flying boat routes. Some lasted into the 60s on commercial routes. The Lockheed Constellation had four 18 cyl radials, and being pressurised survived…

Mass aviation could not have happened without the turbine. The big propliners of the 50s were notorious for having engines fail in flight and had insufficient power reserves to do anything but struggle to the crash site, even with the tiny payloads they carried.

64 years ago today a KLM Constellation crashed at Shannon in Ireland, it was carrying 56 people. That's miniscule and was only sustainable with fares that the 1%ers of the era could afford. A Norwegian 737Max on a thin Atlantic route today carries 186 and that is considered borderline small.

Incidentally the Constellation did have a turboprop variant but Lockheed and GE had a disagreement and it went ahead with pistons instead as the Starliner. Few people even remember that aircraft now because of the 707.

Re: Aviation’s Largest Piston Engine (2016)

#39

Post by maxxxxx »

justin66 wrote: post #37
maxxxxx wrote: post #36

Earlier quoted context omitted.

True. The old 911s were really small. Now everything is way too big, including the Miata. Mine was a 2000 which was already much bigger than the original but the current ones are just way too big. That's not the point of a Miata.

It's funny, I actually admire the extent to which Mazda have managed to keep the Miata small. They're still very easy to pick out in a parking lot when viewed from above, even amidst other sports cars. Is the extra width and weight the Miata has gained over the years down to changing safety standards? I guess on the bright side, in 2019 they're adding a little power.

" I actually admire the extent to which Mazda have managed to keep the Miata small."

To me the new model has lost all of its appeal. It's way too mainstream. The only interesting thing left is the rear wheel drive.

Re: Aviation’s Largest Piston Engine (2016)

#40

Post by quintiles »

dsfyu404ed wrote: post #4
nimbius wrote: post #2

>At full power, the XR-7755 generated a tremendous amount of heat. Speaking as a full time engine mechanic for a small chain of midwestern repair stores, this is the death-knell of every heavily customized car. Heck, 3/4ths of the engineering for a Dodge Hellcat or Mustang cobra is just to keep the thing cool enough that the driver isnt chased out of the cockpit. You cant idle them the same way you idle a Toyota...th…

I'm not seeing how crank and cam specs significantly affect cooling at idle all else being equal. Any cooling system that can work under load will be fine at idle. Edit: For something like a race-car that's trying to minimize weight/power loss by running the minimum radiator/fan necessary and depending on airflow from movement (or rely on the fact that you're only running 1/4mi at a time) I can understand. Still, tha…

RE: Downvoting. Just give up. There is no correlatiing reason for downvoting. Don't even think about keeping a user name for more than a day.

It's not worth trying to please anyone around here anymore. Just cut a fresh user name, dump your honest opinion into it once, and then walk away from that user name.

The amazing part is that HN tends to auto-hellban new users, if two are created by at the same IP address, inside of 24 hours. HN also auto-hallbans for other reasons.

Because of this, there is also a semi-random attrition rate, for new accounts.

In summation, HN doesn't accurately downvote, and HN doesn't accurately ban or hellban. Karma is meaningless, and users are frequently silenced without cause.

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