Why did inline aircraft engines in WW2 move almost universally to V-12s?
The W12 Napier Lion powered a bunch of different planes throughout the interwar years - from stuff that demanded reliability like long-distance flying boats to racers . It was even pushed to 900HP in some 1920s race planes. It would probably give the same performance for a given level of displacement, or have more power for a given form factor.
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What little I know about it (and that's an understatement), the reason was that
>A) Only a few companies knew how to make good W engines at the time
>B) Thinner is better when you're designing a performance aircraft engine and V is the best choice for being both thin and balanced.
The V block engines had higher service ceilings due to more efficient supercharger systems.
Can you elaborate on why it's easier to get high altitude performance out of a V-engine, as opposed to a "broad arrow" W-engine?
Probably better airflow, you can have a central intake manifold and single compressor on a v engine, and only 2 exhaust manifolds. A W needs 3 for the same displacement and probably two compressors minimum.
Just ideas off the top of my head. I’m not an aircraft guy but I am a marine diesel chief engineer and work with big ass turbocharged engines.
Aerodynamic efficiency, mostly. V engines aren't as large spatially, and can be fit into a more compact, arrow shaped frame.
Smaller frontal cross section and is shorter than an inline.
They started using V's before superchargers became common on aircraft.
It’s still true though that the more cylinder banks you’ve got the more separate intake and exhaust manifolds you need.
Reliability.
Shorter crankshafts, camshafts, etc = mechanical reliability.
Basically any form of "Shaft" becomes more prone to damage the longer it gets so eventually you hit a point where the added complexity of slapping an entire cylinder bank onto the engine is worth not adding more main journals to the crank.
On the other end of the spectrum another cylinder bank is a SHIT load of mechanical complexity. The Napier Lion is a duel overhead cam engine so with three cylinder banks that means its got six camshafts. The timing chains (or gears since this is ww2) will wear down, longer chains will wear faster and a bunch of short chains increases maintenance costs.
So to keep it simple 2 cylinder banks and 4 cams is just an engineering sweet spot for high horsepower yet reliable engines.
No one has yet mentioned that they're naturally balanced. That's a huge bonus for an aircraft.
I'm replying to myself cause I found this image.
Its a Napier Lion. May be hard to see but theirs a ring and pinon gearbox at the front of the cams that I assume is connected via a shaft to another gear box at the end of the crank shaft which is connected to the distributors via more gearing and shafts.
If a single one of these cogs is off then the engine wont run, or barely run with the likely hood of bending valves.
Trying to put shit in perspective for people that don't know shit about cars.
This is a chevy small block.
Engine I mean.
I know, but thats probably something convenient they discovered later on
Since OPs question has been answered.
On the subject of aircraft engines, I've spent 8 years working on warbirds and radials. Limited experience on inline and V engines, though. Wright R1820 engines are where I spent most of my time.
AMA
Radial master race
R4360 shits on all of the euro cuck engines
>AMA
Are traps gay?
Jumo opposing piston diesels are even today amazingly efficient and reliable engines. 6 cylinders, 12 pistons and gazillion gears to connect the two crankshafts. Still only Wankels and jet engines are more simple.
*Asplodes in burger*
>On the subject of aircraft engines, I've spent 8 years working on warbirds and radials. Limited experience on inline and V engines, though. Wright R1820 engines are where I spent most of my time.
>AMA
How reliable are these big radials? No one makes light aircraft piston engines much above 400hp anymore but turboprop engine prices remain so extreme people can't build something similar to ww2 fighters with them. Although complex they don't have the extreme temperature and tolerance requirements high pressure turbine cores do.
To be fair, the LS is a pushrod motor, which makes it inherently simpler than the Napier being dohc. I'm sure if the Napier was a flat head it would be simpler than the chevy, but you'd get worst performance. A better comparison would be any dohc v or boxer engine.
This will take some typing to answer.
For radials, reliability depends on how the engine is operated day to day. Most problems are pilot induced.
The leading catastrophic failure for radials is main bearing failure. The main bearing has a high chance of failure within the first 60 hours after a overhaul. Once you get past the 60 hours, the bearing will last 1000 - 2000 hours. Unless a pilot fucks it up.
American airlines got their R1820s to last 4000 hours because they would fly 4 - 7 hour flights and they took care of their engines.
The plane I worked on flew 30 - 40 min flights. I estimated that we do an engine change every 1000 hours regardless of condition. More shutdown/startup cycles, gives us shorter life.
The other part of reliability comes from the engine accessories. All will eventually fail. Fuel pump, pressure carburetor, starter, magnetos, generators, etc. I would always hear complaints by other warbird crews at airshows about how their carburetors would last 2 years and constantly give them trouble. This is because they don't give them the proper care.
Since we knew what we were doing, our carbs never had any problems.
The last are the cylinders. All cylinders will eventually be replaced at least once throughout the engines life.
But their life depends on how hard you push the engine.
A DC3 mechanic called me trying to figure out why he was changing 2-3 cylinders a year and I wasn't. Turns out they were using the old military take off power settings, which was ridiculously high. They were taking off at 46" of manifold pressure, while we were at 38" heavy 36" light.
There is always the unexpected. A cylinder starts puking oil, an exhaust piece is blown off, ignition problems, etc.
I always had a spare parts box and tools in the plane whenever we left town. Spare cylinder, voltage regulator, set of brakes, and one of all the accessories except a carb. We broke down a few times but we were back flying before the day was out.
Why didn't they use doritos?
V-engines have more space for the cylinder heads which means you've got more space for fuel injectors/carburators, spark plugs, exhaust piping, etc.
You can get more "Enhancers" on a V engine while not being as fuckhuge as a rotary.
Radials are cooler than inlines
I would say that the radial engine is the logical conclusion of a V engine. What is a V engine but a mere fragment of a Radial.
Unfortunately, you can't fit a Radial in a car. Well...not practically.
$3,360 just to change all the sparkplugs in this.
What would an ideal hindsight fighter ready for the outbreak of war look like?
Thank you based Kurt of pilot ergonomics
Sweeeeeet.
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