Greatest aviation myth this site “de-bunked”.

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Zippythehog said:
AFAIK, turbine engines are the motive force that turns propellers on airplanes. At least that was the case for the King Airs I've flown.
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In WWII, the prop was turned by an internal-combustion engine. That IC engine often had additional aspiration via a supercharger or a turbocharger, or occasionally both.

A supercharger runs off a driveshaft powered by the engine itself. A turbocharger is spun up by the exhaust from the engine. Both systems act to compress air going into the cylinders in order to produce more power therein by more complete burning.

Both are indeed miniature turbines, but they are not turbine engines and while they can add power to an internal-combustion engine, they do not power the plane itself. One is a turbine driven by a PTO shaft, and the other is a turbine driven by exhaust-gas efflux, and both only add to cylinder efficiency or pressure, I can't remember exactly. But neither power the plane, they only add thrust to the powerplant itself.
 
The Beechcraft 360 (King Air) is powered by turbo props, which are literally jet engines with a propeller attached to the turbine's center shaft.

There is no relation between a supercharger/turbocharger and a turboprop.

In the automotive world, a turbo on engines (gas or diesel) are driven by a duct from the exhaust manifold, which turns the impeller that drives the air/fuel mixture into the engine intake.

Additionally, on high-performance vehicles, such as street rods and dragsters, a "blower" aka Supercharger, is a belt-driven compressor situated between the carburetor (or throttle-body injector) and cylinder heads that compresses the air-fuel mixture and forces it into the cylinders.

This vehicle technology is born from experiences gained in tje aircraft world.

So a belt-driven hotrod supercharger, was typically a shaft-driven device on a WWII aircraft.
A turbocharger on a WWII aircraft was driven by the exhaust gasses passing from the exhaust manifold, just like on modern vehicles.
 
OK.


wooden model, turbine details are little scarce.


These are rare instances of turbo supercharged aircraft engines where the turbo is the ONLY form of supercharging. The exhaust driven turbine drives the compressor which feeds the carburetor. There is no engine (gear) driven supercharger.
The US built about 60 such aircraft of various types, all using the Curtiss Conqueror engine, which in just about all other uses did not have any supercharger of any type.
These were the only US aircraft that did NOT use a two stage system. Turbine powered compressor feeding a gear driven compressor in series.

I would be leery of using old text books or reference books. Terminology changed a lot in the mid 40s. Turbo-props were sometimes called propjets. Rocket planes were called rocketjets (a little redundant). They had turbojetfan, all one word but used to describe both ducted (fans inside of duct) and open fan engines. Sticking 'jet' in everything fell out of favor.
 
Pisses me off too. When did fighters become fighterjets? I remember when anyone talking air superiority aircraft said "fighter". This is from the early Sixties to about ten or so years ago. It's the twenty first century. A non jet fighter would need the further descriptor.
 
I think some of stems from a differentiation between pure Attack jets and those that can do both attack & air to air or air superiority only. I would lump the A-7 A-10, F-111, F-117 and RF-4 into the "non air to air" group, and the F-15 F-16 into the good at "air to air". In the USAF we called all of the guys / gals who flew these fighter pilots. The USN delineated between Attack and FAGs (Fighter Attack Guys). The Attack guys generally being a bit of a second class citizen. Therefore "fighter jets" might stem from the other than attack types. It also could stem from the period of early jets, hence the references to jets.

Probably more shades of grey than anything else.
 
However, I am seeing an increase in the term "jet" after the name of a WWII fighter type.

The most recent, was a post on a popular social media platform (where I used to get tons of material to post in the "History according to random people" thread), that claimed that the: "Supermarine Spitfire Jet Saved Britain From The Nazis".

I kid you not - plus the comments were just about as stupid...
 
I've seen the term used in supposed mainstream news articles. Journalists aren't terribly informed.
 
Turbine engines, though, are not supercharged or turbocharged. Those terms could apply if there were to be forced-air induction to the turbine section. I don't know that I have ever seen or heard of a forced-induction turbine engine.

Interesting to think about, though.

The compressor up front could be seen as forced-air induction. So maybe all turbine engines are supercharged?

But a turbine connected by a shaft to the compressor in front of the combustion chambers is driven by the exhaust, so maybe all turbine engines are turbocharged?

To date, I have considered only piston engines as supercharged or turbocharged. Perhaps it is time to think about the application to turbines.

Many jet engines have a shaft connecting the jet turbine to the compressor. But some have no connection between them and use the intake air stream to spin the compressor. The intake air stream is NOT exhaust, so it isn't turbocharged. The compressor is not driven by the shaft, so it is not supercharged. Perhaps there should be a new term for a compressor driven by the intake airstream?

The new term almost has to have "charged" in the name. Blowcharged? Streamcharged? Freecharged?

Ah well, fun to think about. Thanks for making me think about it, though!
 
Zippythehog said:
BTW, GregP, is that a Van on your avatar?
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Yes, sort of. It's a drawing I made of an F1 Rocket. Somehow, it doesn't seem to show the entire drawing, and it shows in low-resolution.

F1 Rocket:


Basically, it's a stretched Vans RV-4 with one bay removed from each wing, and a big Lycoming six cylinder engine in place of the usually 4-cylinder engine. The F1 is a version that comes from the Czech Republic. The difference from the Harmon Rocket is the windscreen.

Rate of climb is WWII fighter-ish at 3,900 fpm, and top speed is around 235 knots, with cruise at near 200 knots. It is gentleman aerobatic at +6, -3 g's, so your Lycoming better have an AIO in front of the displacement number.

Harmon Rocket below:


Note the different windscreen.

Here's the original drawing I made:


Very incomplete and not detailed, but it was supposed to be a basic signature pic.

I have to say, great catch there!
 

As GregP says if the engine directly drives the compressor it is supercharged and if the compressor is driven by a turbine powered by exhaust gases it is turbocharged (normally as well as supercharged). If the exhaust turbine drives the propeller and supercharger via the engine (instead of directly driving the compressor) it is turbo compounded.

Look at it this way.

On a piston engine the engine is mounted between the compressor and the turbine of a turbocharger.

On a basic turbine engine the piston engine is replaced by a combustion section that heats the air so that it has far more volume and the turbine extracts energy in the form of heat from the combustion air and uses that to not only drive the turbine(s) but to move the aircraft with the residual energy available in the exhaust of the turbocharger.

In a turboprop, turbofan or turboshaft engine the turbine(s) extract a far higher percentage of the heat energy and converts that to drive the prop, fan or output shaft and there is very little residual energy to produce thrust.
 
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The "Spitfire jet" was actually the Supermarine Attacker, I believe. I also decry the lack of knowledge people in general display about aviation, considering it's impact on society as a whole.

The "Tempest jet" was actually the Hawker Sea Hawk that morphed into the Hunter, through the Hawker P.1062, 1067, and 1068. In some cases, as you all well know, there were many interim "steps" leading to these end-item jets.
 
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GregP said:
The "Spitfire jet" was actually the Supermarine Attacker, I believe.
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The artical was about the Battle of Britain, which would have been the early Spitfire marks and it went on to state that the Spit was Britain's only hope.

I suppose the Hurricane (which was never mentioned) was just window dressing...
 
MiTasol said:
Look at it this way.

On a piston engine the engine is mounted between the compressor and the turbine of a turbocharger
Click to expand...

A supercharger is driven by the engine via PTO shaft. It gives higher boost sooner at some cost to power, because rotating an impeller takes energy and a supercharger draws that direct from the camshaft.

A turbocharger is driven by exhaust gases, which means is doesn't spool up well until the engine does so, but captures some energy from exhaust to compress the air inflow. The impeller is driven by outflow and not a power-take-off.

I know you know this stuff and ain't trying to grab your short hairs, I just want to make the mechanics clear to readers.
 
Looks like it's as slick as a greased watermelon seed. Is it a kit, plans build, or factory?
 
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