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Questions tagged [piston-engine]

Piston (reciprocating) aircraft engines are internal combustion engines, similar to the type found in most automobiles. They are typically gasoline powered.

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Do ARFF units need special equipment for responding to crashes or fires involving piston-engine aircraft?

Unlike jets and turboprops, which generally burn (relatively) benign jet fuel (usually a straight kerosene, occasionally with plain gasoline blended in as a freezing-point depressant), piston-engined ...
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Why are piston-engined aircraft generally exempted from U.S. flight recorder requirements?

Most, if not all, of the FAA’s requirements for carriage of flight recorders do not apply to piston-engined aircraft. For instance, 14 CFR 91.609(c)(1) (emphasis added): No person may operate a U....
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Why would a C150 tachometer be sluggish?

After having an issue with a tachometer bouncing so much that it fell off, I now have the opposite problem with the replacement (Mitchell D1-112-5025): The tachometer is sluggish. When I open the ...
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What is the blue range indicating on this manifold pressure gauge?

This is baffling me. Does anybody with experience with this type of indicator have any idea what the blue range of this gauge means? It's mounted in a mock-up panel. I know nothing about where it ...
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Why would a cylinder not work below a certain RPM?

We have an IO 540 Lycoming engine, and cylinder #3 doesn't work below 1900 RPM (cold to the touch; EGT and CHT are zero; no vibration). The engine is new, what could be the cause(s)? We cannot ...
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Why is carburetor heat unnecessary at full throttle?

Questions like How does aircraft design affect carburetor ice? show how carburetor mount point affects the relative passive heating of the carburetor by the engine, but I've never learned why full ...
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Why would a C150 tachometer bounce so much that the needle fell off?

On a long flight in a C150E, the tachometer started bouncing a little bit and the severity of the bouncing gradually increased until it was extreme: The tachometer was spinning in loops and making a ...
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266 views

Why did most WWII Allied piston engines not use fuel injection?

One would think that given the huge push for ever more performance and reliability on piston engines during the heat of WWII would push the designs to their absolute limits, however, most American ...
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What is the main reason of air-cooled radials producing much less HP/L compared to liquid cooled Vs?

Is it because of the inherent limitations of cooling the cylinder walls, only 2 valves per cylinder, relative ease of scaling up instead of dialing up the boost, or some other reason?
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Is the Meredith effect utilized in the cowling design of air-cooled engines?

The P-51 is famous for its advanced-for-its-time aerodynamics, the prime example of which is the radiator design under the belly which utilizes the Meredith effect to, in effect, turn it into a mini ...
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Why do carburetors tend to produce richer mixture at higher altitude?

The pressure drop in the venturi is proportional to air density and the fuel is at ambient pressure in the float chamber, so I would expect the fuel flow to reduce proportionally with density, and ...
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Are WWII turbochargers reliable?

How reliable are WWII turbochargers? Does adding them to an otherwise reliable engine, e.g. the P&W Double Wasp and the Allison, decreases the overall reliability of the engine? Are they well made ...
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What changes are needed for a piston-prop aircraft to withstand saltwater environment?

I'm interested in WW2-era piston-prop aircraft. I want to know what changes are needed to make the aircraft withstand saltwater corrosion. Presumably these are different and more expensive than the ...
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363 views

Why don't air-cooled radial engines use fuel to cool the oil?

Having read up on WWII air-cooled radials, one thing that struck me is how frequent is the mentioning of external oil cooler overheating, or the need for armored boxes around it, and some even venture ...
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Why are piston engines so unreliable in airliners?

Before the first jetliners appeared, all airliners used piston (reciprocating) engines, which were astoundingly prone to failing in flight, to the point where an inflight engine failure was an ...
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Why would you NOT lean on takeoff with a Lycoming engine?

There is an excellent question/answer on leaning here. However what I have not yet understood is why one would NOT lean for takeoff below 3000 feet? Why does the Lycoming Service Directive 1497A/B ...
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What is the cooling air exhaust velocity for the piston engine of a propeller driven aircraft?

Piston engines of propeller driven aircrafts need to be cooled. There are engine cowlings which accomodate the inflow of air to "wash" over the engines within them and which is then exhausted out into ...
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Why cycle the magnetos before engine shutdown?

Inspired by this question asking about shutting down a light aircraft engine I realised there is another ritual which I do, but have long forgotten the reason why. Having parked a light aircraft, and ...
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Why in the Seneca 2 the Rated Horsepower are higher at 12000 feet than at sea level? (215Hp at 12000feet, 200Hp at sea level)

Reading the POH I found that the Rated Horsepower at 12000 Feet are higher compare to sea level. I have in the past studied the back pressure of the exhaust gasses but I cannot completely understand ...
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1answer
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Why did the Daimler-Benz DB 605 compression ratio vary between cylinder banks?

The Daimler-Benz DB 605 was an inverted V12. The compression ratio of the 2 banks varied slightly. Why did the designers do this? Compression ratio: 1:7.3 right bank, 1:7.5 left bank (museomotori....
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2answers
268 views

How does the throttle position affect the speed of airflow to the engine?

It is said that the less we open the throttle the slower is the speed in Venturi tube, thus less reduction in pressure and less fuel is being sucked from float chamber, however, actually if we reduce ...
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Does engine oil have a shelf life?

Suppose that I buy a case of oil. For some reason I stop flying and the oil sits in storage for a sufficiently long time. After that, I decide I want to put it in my engine. Is there a point after ...
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In a piston aircraft engine, how much heat must be removed by the oil cooler?

It is pretty straightforward to compute the heat and power generated by the combustion process, given the displacement, RPM and fuel mass flow rate. Similarly, the power exhausted can be computed with ...
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1answer
124 views

Do two stroke engines for small aircraft suffer from degradation between overhauls?

Do two stroke engines for small aircraft suffer from degradation between overhauls? For an automotive engines you can usually expect it to retain most of it's power between services for a long time ...
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Why does enriching mixture over stoechimetry give more power ?

In other words, in a piston engine, the Best Power mixture is richer than the EGT peak that signs for a stoechimetric combustion. Why is that, physically ?
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181 views

How to lean with constant speed prop on multi-engine aircraft without EGT

This question is more about the indication of engine roughness. The procedure for leaning without an EGT is clear in the POH and Lycoming documentation which basically states as follows: Best power: ...
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249 views

Is this test question correct about the causes of detonation?

So detonation is explained brilliantly in the answer of this question. In the accepted answer, NathanG goes on to say the following: the octane rating of a fuel is basically the amount of pressure ...
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1answer
470 views

How does a rotary piston (radial) engine work?

How does a Gnome rotary piston engine work? I would like to see how it works in detail, possibly with text explanation.
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1answer
183 views

How much extra weight is added by strengthening a piston-prop fighter for carrier landings?

To land on a carrier, an aircraft must be strong enough to withstand sudden deceleration by the tail hook catching the arresting wire. I think it also requires strengthening the undercarriage to ...
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1answer
141 views

Voltage induced in high-tension magneto ignition system

Why is there no voltage induced into the secondary winding (in high-voltage step-up transformer) when the ignition switch is closed (OFF). When the current flows in the primary winding of the coil a ...
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1answer
546 views

Why does fuel vaporize in the carburetor?

So I get that a carb vaporizes fuel and mixes it with the air intake for the engine. But my question is what is the explanation for what causes the fuel to vaporize after it exits the fuel nozzle?
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What is a biplane propeller and how efficient is it?

Lazair ultralight series II used biplane props to absorb more power from the engine....so my question is what really is a biplane propeller and are they efficient in comparison to a four bladed prop?
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How does ice affect the combustion systems of jet and piston aircraft engines? [closed]

What are the effects of ice on a jet and piston aircraft engine? I've tried Google but I'm not satisfied with the results.
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1answer
457 views

Why would one cylinder on a Continental O-200 run cold at idle?

I have a Luscombe with a Continental O-200 engine. The #4 cylinder is running cold at idle, does anyone have an idea why? The other three cylinders are running fine. Some extra information: The ...
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1answer
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What is this aircraft that has both piston and jet engines?

A friend sent me this picture of a trimotor aircraft with what looks like two radial engines and a jet in the middle. He didn't know what is was and neither do I. Anyone recognize it?
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A modern replacement for DH.82's Gipsy Major engine

While I deeply appreciate any vintage aircraft that is powered by their original engines, I was wondering if there are any modern replacement engines available for the de Havilland Tiger Moth aircraft ...
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How long does it take for a propeller engine to spool-up?

To build further upon the question Why does a turboprop lag?, the following: Assuming a propeller engine is running in idle and the throttle lever is switched to full thrust instantaneously at t = 0 ...
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What is the throttle setting of a piston aircraft during cruise?

I am learning to fly nowadays, I am sorry if this sounds like a dump question. What is the throttle setting of an aircraft during cruise flight? After stabilizing the flight after climb do i need to ...
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1answer
249 views

Do Red Bull Air Race aircraft make use of nitrous oxide injection?

Microsoft Flight Simulator X contains Red Bull Air Race missions where the player flies an Extra 300S through a race course and makes use of Nitrous Oxide injection for the engine. While I have heard ...
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2answers
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Why isn't the application of “carb heat” in initial piston multi-engine failure emergency procedures?

What is the rationale for not including the application of carb heat in the initial multi-engine airplane's engine failure procedure? I've recently starting flying light multi-engine airplanes again ...
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1answer
659 views

Why aren’t diesel piston engines used on aircraft like the Saab 340 or L-410?

In contrast to this question (link), I would like to know the opposite - why diesel piston engines aren't used on aircraft with comparable role and configuration to Saab 340, L-410, ATR-42? There's ...
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3answers
481 views

Which modern day prop (piston) engines allow for inverted flight?

A buddy of mine is looking to buy an airplane with an old radial engine because he says radial engines can fly inverted in aerobatic flying. What modern day engines (engines that you can buy today), ...
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2answers
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Which engine manual must a pilot legally use?

Many aircraft have engine/prop performance information provided by the manufacture such as Bonanza, Cessna, Mooney, etc AND the engine manufacture. The performance or recommended settings may vary ...
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1answer
426 views

Is feather edge bad?

Currently learning about aircraft piston engine. Feather edge can be found at the engine valves as according to the picture. Can someone explain briefly about what is feather edge? Why it is bad? ...
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3answers
7k views

Why did the turbojet replace the piston engine?

Many people say that this was because aircraft powered by turbojet engines were faster during WWII. However the Grumman F7F-4N Tigercat, a fighter powered by a piston engine, flew at a maximum speed ...
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384 views

Why would the engine quit when turning on the R magneto after an overhaul?

I just finished overhauling a Lycoming O-360; it's currently on a stand, i.e. it's not in the aircraft. I replaced the capacitors and point gaps on both the L and R mags. I adjusted the E-gap and ...
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515 views

What is the reason for the different types of valve heads (mushroom, tulip, semi tulip) in reciprocating engines?

I am reading in the FAA-H-8083-32 Aviation Maintenance Technician Handbook-Powerplant book posted on the FAA site that there are engine valves with different types of head shapes, e.g. mushroom, tulip,...
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How would a new “clean sheet” General Aviation piston engine with all the latest technology differ from existing Continental/Lycoming types?

My understanding is that current GA piston engines from Continental and Lycoming are based on a design from the 1960's. There have been many evolutionary improvements, but only within the limitations ...
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245 views

How are rotary engines controlled?

Listen closely to the engine sound here. It seems to me all rotaries continuously sound on/off. Is that a pilot application to manage the engine's torque (with the whole block rotating), or as ...
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Why do most radial engines use an odd number of cylinders?

To help suppress vibration, most 'V' and 'horizontal' engines use an even number of cylinders as closely opposed as possible. Radial engines are well known for excessive vibration. For some reason ...