Inverted aero engines

General engine tech -- Drag Racing to Circle Track

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peejay
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Re: Inverted aero engines

Post by peejay »

rfoll wrote: Sat Sep 15, 2018 3:46 pm A word here about productivity. I heard a story about the German tanks. Marvels of engineering, but difficult to produce in quantity. The Russians statistics were that a tank an average of 11 minutes in combat, so rather than use complicated roller bearing assemblies in the wheels, they made due with bushings and the like.
I'm sure those fancy German tanks could get more than 11 minutes of combat if there was oil to fuel them :D

Some of those designs were nuts. If you had to change an inner roadwheel on one model, you had to remove nine or fourteen or something other wheels to get to it because of how they overlapped.
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Re: Inverted aero engines

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peejay wrote: Sat Sep 15, 2018 6:07 pm
rfoll wrote: Sat Sep 15, 2018 3:46 pm A word here about productivity. I heard a story about the German tanks. Marvels of engineering, but difficult to produce in quantity. The Russians statistics were that a tank an average of 11 minutes in combat, so rather than use complicated roller bearing assemblies in the wheels, they made due with bushings and the like.
I'm sure those fancy German tanks could get more than 11 minutes of combat if there was oil to fuel them :D

Some of those designs were nuts. If you had to change an inner roadwheel on one model, you had to remove nine or fourteen or something other wheels to get to it because of how they overlapped.
yup 12:30 worth of combat. typical overly complex designs that the germans liked to use.
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Re: Inverted aero engines

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ptuomov wrote: Sat Sep 15, 2018 11:31 am
gruntguru wrote: Tue Sep 11, 2018 9:21 pm
ptuomov wrote: Mon Sep 10, 2018 9:30 pmI don’t think there was a better plane on the allied side than Messerschmidt ME-262. That plane obsoleted all propeller fighters.
Certainly a much higher performance aircraft but needed a lot more development to be any threat to the outcome of WW2 even had it been available in large numbers. Biggest issue was maintenance intervals and service life of the jet engines.
I agree that it wasn’t the end of jet development, but it did have a 4:1 aerial combat kill ratio while fighting against vastly superior numbers. The allied air forces had to destroy those planes on the ground.

Of course no single weapons system had any potential to change the outcome of the war, after the US joined.
Sure there was ONE game-changer and the Germans came up with it and we ended up with it..

NUKE BOMB's!! And we proved it on Japan!!!

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Re: Inverted aero engines

Post by Truckedup »

rfoll wrote: Sat Sep 15, 2018 3:46 pm A word here about productivity. I heard a story about the German tanks. Marvels of engineering, but difficult to produce in quantity. The Russians statistics were that a tank an average of 11 minutes in combat, so rather than use complicated roller bearing assemblies in the wheels, they made due with bushings and the like.
The Russians literally threw men and equipment at the fight and suffered horrendous casualties...Much of their stuff was very crude but often effective. They lacked the materials and knowledge to make flame resistant aircraft fuel tanks..So they diverted some exhaust gasses into the fuel tank to displace oxygen...
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Re: Inverted aero engines

Post by hoodeng »

The suspension system used on a lot of German tracked equipment was the 'Christie system' [American designed by J. Walter Christie in around 1919], in its day the fastest tracked system over land , derivatives could have the tracks removed and use the sets of wheels directly on the surface it was running on for even higher speeds.

The post 1940 Russian 'T' series tanks were diesel so making them much safer for its crews and with good range, these were predominately built with the 'Christie system' as well.

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Re: Inverted aero engines

Post by ptuomov »

pdq67 wrote: Sat Sep 15, 2018 7:36 pm
ptuomov wrote: Sat Sep 15, 2018 11:31 am
gruntguru wrote: Tue Sep 11, 2018 9:21 pm Certainly a much higher performance aircraft but needed a lot more development to be any threat to the outcome of WW2 even had it been available in large numbers. Biggest issue was maintenance intervals and service life of the jet engines.
I agree that it wasn’t the end of jet development, but it did have a 4:1 aerial combat kill ratio while fighting against vastly superior numbers. The allied air forces had to destroy those planes on the ground.

Of course no single weapons system had any potential to change the outcome of the war, after the US joined.
Sure there was ONE game-changer and the Germans came up with it and we ended up with it..

NUKE BOMB's!! And we proved it on Japan!!!

pdq67
You could've given Hitler a single fission bomb and its blueprints in 1944 and they still wouldn't have won. How many of those could've they made, after allied campaign to slow down nuclear development in Germany? What delivery system would've they used against the US, given that they didn't have the resources to complete the Amerika bomber program? Etc. The US B-29 program cost twice as much as the Manhattan project, so the Germans wouldn't have had the resources to do much with those bomb blueprints.
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Re: Inverted aero engines

Post by Truckedup »

The B29 and the A bomb were originally for destruction of Germany and other enemies in Europe. The US thought the UK would fall to the Nazis and the Soviets would be unable to hold their own.. The B29 program was stalled several times due to engine problems..The engine installation was a complex system of ducting but the engines often overheated and caught fire..Cylinders would lean out causing detonation...The engine would seize and the propeller gearbox would fail...If you were lucky the prop would spin like crazy and fly off...or fly into the aircraft..Or the prop seized tearing the engine from it's mounts and fall away..
If you have any interest, do buy "Superfortress", the book written by General Lemay who was the commander of the WW2 B29's in the Pacific..Or the expensive but comprehensive "V's for Victory, Allison V-12 engine development.....Another good one is "Allied Piston Engines of WW2" by G White...
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Re: Inverted aero engines

Post by grandsport51 »

Fascinating reading on B-29
and the heros keeping 'em flying!
http://www.lanbob.com/lanbob/HDL-V1943- ... G03NF3.htm


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Re: Inverted aero engines

Post by peejay »

grandsport51 wrote: Sun Sep 16, 2018 9:37 am Fascinating reading on B-29
and the heros keeping 'em flying!
http://www.lanbob.com/lanbob/HDL-V1943- ... G03NF3.htm


Dave B
THANK YOU for that!

A very good read indeed!
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Re: Inverted aero engines

Post by Krooser »

lefty o wrote: Sat Sep 15, 2018 6:37 pm
peejay wrote: Sat Sep 15, 2018 6:07 pm
rfoll wrote: Sat Sep 15, 2018 3:46 pm A word here about productivity. I heard a story about the German tanks. Marvels of engineering, but difficult to produce in quantity. The Russians statistics were that a tank an average of 11 minutes in combat, so rather than use complicated roller bearing assemblies in the wheels, they made due with bushings and the like.
I'm sure those fancy German tanks could get more than 11 minutes of combat if there was oil to fuel them :D

Some of those designs were nuts. If you had to change an inner roadwheel on one model, you had to remove nine or fourteen or something other wheels to get to it because of how they overlapped.
yup 12:30 worth of combat. typical overly complex designs that the germans liked to use.
Sounds like today's VW, Audi and MB offerings...

My Mom worked at a weapons plant producing ammunition...my Dad, at are 42, enlisted in the Navy and served as a gunners mate for four years winding up on the Wisconsin firing those 16" shells at Japan. One brother enlisted at age 16 and served in the Navy in Indochina. My other brother was in ground support in England servicing B-29's.

God Bless all who served at home or overseas.
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Re: Inverted aero engines

Post by numboltz »

I know it's old technology, as high antiknock gasoline is no longer needed/available, but
just for the record there is no such thing as 150 octane gas, or 130 octane etc.
There are quite a few octanes, some of which have a low octane rating, BTW. Iso-Octane
was picked as a reference fuel as it did have a high anti-knock characteristic and blending
it with normal Heptane in known quantities was used to establish the Octane rating of
a specific gasoline by testing in the official Waukesha CFR engine, which was designed for
fast and easy compression ratio changes.

http://www.waukeshacfr.com/about

Obviously, as pure Iso-Octane has an Octane rating of 100, so that is the upper limit of the
Octane scale. Iso-Octane, like some other fuel types is very sensitive to small additions
of tetra-ethyl lead [TEL] so Iso-Octane and say, 4cc/US Gal TEL added to Iso-Octane gives a
rating around 108.

So when high supercharge pressures for aircraft engines appeared on the eve of WW2
the newly dreamed up test known as the "octane rating" was not enough and the Performance
Number test procedure was developed. It used the CFR engine [above] for testing but it
was supercharged to various levels as needed.

WW2 was basically fought with 100/130 Avgas wherein the LEAN knock rating was 100 and the
RICH knock rating was 130. The PN scale crosses the Octane scale at 100, in other words a
fuel that CFR tested at 100 Octane would also test as 100PN. So 100/130 would have the same
[knock limited] horsepower limit as 100 Octane gas whereas the engine could be operated at
30% higher power with a RICH mixture before the knock limit was reached. Most WW2 military
aircraft piston engines did not have the throttle wide open at their max HP output except above
the CRITICAL ALTITUDE. So, getting another 30% power was often just a matter of opening the throttle
more [see To The Gate and Through The Gate]

Almost all WW2 era Avgas came from America, and the Brits doctored quite a bit of theirs and called
it 150PN. To understand why you need to know the difference between MILD and SEVERE
engines. The Brits used a lot of liquid cooled Merlins in combat [they had lots of good air
cooled types, too] and USUALLY liquid cooled engines were MILD while air-cooled were
SEVERE. This was because of the 1/3 rule.

Lastly, claiming the Germans had better aircraft engines than the USA/Britain is not borne out
by the facts. Needless to say, the Germans turned out decent stuff but, believe it or not, their
bureaucrats were far worse than ours at that time in history and beside, our man in Berlin assured
us a win. He made sure no long term designing or planning took place. That is why the Mercedes
and other V-12s needed far larger displacements [and weight] to get the same HP as Allisons and
Merlins. Their main supply of gasoline came from coal gasification, an advanced production method,
but they didn't have the fuel quality needed for high boost pressures.
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Re: Inverted aero engines

Post by Kevin Johnson »

I am sorry that you lost so many of your references; very few people go to the trouble of reading multiple editions and comparing them.
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Re: Inverted aero engines

Post by Truckedup »

numboltz wrote: Thu Sep 27, 2018 1:38 am
WW2 was basically fought with 100/130 Avgas wherein the LEAN knock rating was 100 and the
RICH knock rating was 130. The PN scale crosses the Octane scale at 100, in other words a
fuel that CFR tested at 100 Octane would also test as 100PN. So 100/130 would have the same
[knock limited] horsepower limit as 100 Octane gas whereas the engine could be operated at
30% higher power with a RICH mixture before the knock limit was reached. Most WW2 military
aircraft piston engines did not have the throttle wide open at their max HP output except above
the CRITICAL ALTITUDE. So, getting another 30% power was often just a matter of opening the throttle
more [see To The Gate and Through The Gate]

Almost all WW2 era Avgas came from America, and the Brits doctored quite a bit of theirs and called
it 150PN. To understand why you need to know the difference between MILD and SEVERE
engines. The Brits used a lot of liquid cooled Merlins in combat [they had lots of good air
cooled types, too] and USUALLY liquid cooled engines were MILD while air-cooled were
SEVERE. This was because of the 1/3 rule.

I have a collection of books on WW2 aircraft engines, some of it was observation from combat zone mechanics and pilots....The liquid cooled engines made more HP per cubic inch that the radials and used much higher supercharger pressure and engine reliability of the liquid cooled Merlin and Allison was affected by detonation...Allison engines in the P-38 had serious reliability problems from detonation in cold European air, mostly caused by poor mixture distribution causing a lean cylinder...The Allison and Merlin were designed to run at 250F coolant temperatures ...
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Re: Inverted aero engines

Post by numboltz »

I had a number of microfiche reels from USAFHRC. You pick a pre-packaged reel with stuff you
want and it comes with all kinds of other stuff from WW2. That there was some interesting schiff.
Only problem I had was there was only one reader in one library and they got real twitchy if you
were on it too long. But the stuff they did and went through in WW2, like spark plugs at high boost. And then there was the "day of fire" tables some suit dreamed up for bomber defensive fire. The boys were using about 10x the calculated amount of 50 cal. But they somehow got the ammo and M2 barrels to them, no one ever thought about ordering them not to hose down the Krauts so enthusiastically.

They were supposed to be cleaning plugs every 10 hours but the crew chiefs just put in new ones. What a hell of a scramble they had coming up with new manufacturing capacity for millions of plugs/month. They did it and no one ever thought to tell the mechanics their business. In fact, if General Ratched mis-assigned a V-1710 qualified mechanic he got a nasty letter from Hap Arnold, the big AAC boss. Do it twice and you are OUT OF THERE. That's exactly what happened to a General that took mechanics off P51 fuel tank mods and put them on VIP transport mods. They fired every single suit at that station. This was all 8th AF stuff. Sorry for the OT.
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