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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3answers
189 views

Why weren’t large, high-power radial engines built to take advantage of the Meredith effect?

Most aircraft piston engines fall into two general categories:1 Radial engines (radials for short2) have their cylinders radiate out from the crankshaft in a star pattern; they tend to have a blunt, ...
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4answers
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What is an aircraft magneto?

I know that magnetos are related to the engine and that on many planes, they are used to start the engine. But what exactly do they do in the engine?
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What are the different types of procedures for starting a fuel injected engine?

Can someone explain the various types of procedures to start a fuel injected piston engine? What is a cold start, hot start, etc.? I'm referring to a GA aircraft.
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Did people really hand-start big bombers in WWII?

I am not a pilot so I don't know anything about hand starting propeller aircraft. But I wonder how easily can the propeller fire up unexpectedly during the procedure even if it's done right. Whenever ...
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2answers
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Is a 3 horsepower engine powerful enough for a 100 pound ultralight? [duplicate]

I'm building an ultralight and it weighs 100 pounds empty. My only engine is 3HP. Is that good enough?
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2answers
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What is the method to find the resonance frequency of a PowerFlow exhaust?

I asked a related question about PowerFlow Exhaust systems, which produced another question for me: How do they go about finding the resonance frequency so they know how long to make the exhaust pipe? ...
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2answers
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Why could a Rotax 914 light aircraft lose power at 7000 feet?

I was flying an RV 4 equipped with Rotax 914 engine and variable pitch propeller. The problem was observed during flight above 7000 feet; vertical speed became 0, RPM overshoot for 2, 3 seconds to ...
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2answers
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Why does pulling the mixture to idle cutoff increase the RPM slightly?

When adjusting fuel control on a reciprocating engine, why is there a slight RPM rise (50-RPM rise) when pulling the mixture control to idle cutoff? Why if more than a 50-RPM rise, carburetor is set ...
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5answers
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Does the power behind the engine make any difference to how strong the thrust is? [duplicate]

What difference does horsepower make? If the engine can spin the propeller fast enough, why does it need power behind it?
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4answers
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Is it possible to power an ultralight airplane with a single-cylinder weed-whacker engine?

Plane: Weighs 200 pounds. 16 FT wingspan, 36in. by 5 in. airfoil Engine: 3,000 RPM, 2 HP Propeller: 4ft with 4 blades and weighs 4 lbs. Is there perhaps an equation that could determine this?
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2answers
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How common are gear-driven or belt-driven superchargers in modern aircraft?

How common are gear-driven superchargers in modern piston-engine aircraft, either alone or in combination with exhaust-driven turbochargers? What are some examples of modern aircraft that use them? Is ...
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2answers
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In the modern aviation context, is the word “supercharger” generally assumed to mean a gear-driven system rather than an exhaust-driven system?

In the modern aviation context, is the word "supercharger" generally assumed to mean a gear-driven system rather than an exhaust-driven system? At one time the word "supercharger" often was used to ...
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5answers
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Is a turbocharged piston aircraft the same thing as turboprop?

Simple question, and I've always assumed that they are the same thing, but I'd like feedback from someone who knows more than me :)
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1answer
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Do ultralights need to have EPA-compliant engines in the USA and Canada?

Do ultralights need to have EPA-compliant engines in: The USA? Canada? Just wondering if you could use a hobby type 2 stroke engine for a twin engine Lazair type ultralight. I don't think they are ...
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3answers
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Why are engines with carburetors hard to start in cold weather?

Why are engines with carburetors hard to start in cold weather? And why is there a different procedure for hot start scenarios, after you've just shut down the engine and want to power up again?
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1answer
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Where do the compressed gasses of a charged engine goes?

Good day to you here. I'm working on a modified version of 2-stroke engine. My plan is to use a supercharger for the scavenging process, instead of the conventional Crank case scavenging technique, ...
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2answers
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How can I decode Lycoming engine number?

How can I decode Lycoming engine number suffices? What does D3G mean in o-320-D3G or D2A in o-320-D2A? Is there any chart or tabel for decode suffixes?
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6answers
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Why are two-stroke engines nearly unheard of in aviation?

Almost all aircraft piston engines are four-stroke engines, with one power stroke per piston every other crankshaft revolution and a great deal of intricate moving parts which are only too happy to ...
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2answers
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What are the durations of strokes and events in a 4-stroke engine?

I'm learning about engines, and I understand the basics of how a 4-stroke engine works, but I've seen lots of true or false questions such as "The power stroke is shorter than the intake stroke" or "...
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1answer
631 views

Is there an actual rated thrust for a Cessna 172 engine at takeoff power?

I could approximate the thrust by knowing the weight of my aircraft and timing the acceleration to takeoff speed, but I think that would be a little dangerous of me as well as only an approximation ...
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1answer
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What is the metal bit in the front of this propeller spinner?

What is that grey spirally bit in front of the propeller mounted on this Shvetsov ASh-62 radial engine?
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2answers
272 views

Determining total engine life in relation to SMOH/SFOH

When evaluating the value of an aircraft, the total hours since major (or factory) overhaul (SFOH/SMOH) is an important indicator of price since it tells us how many hours the engine has operated ...
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1answer
499 views

Causes of High CHTs

I have a Long EZ with a Lycoming O-320 E2D. It had a complete top-end overhaul two years ago, in June 2017. All four cylinders were relined, and pistons and rings were replaced. Since then the ...
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1answer
660 views

Does the mixture and throttle setting affect the quality of priming of fuel prior to start?

This question is a generality. For airplanes with small reciprocating engines, does the mixture and throttle setting at the time of priming affect the quality of the priming or the engine start, or ...
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2answers
482 views

What is the difference between an engine “shut down”, “cut-off” and “cut down”?

Explain please for non-native speakers the difference between these engine (jet or piston) terms: shut down cut-off cut down I'm studying at a civil aviation university to become a pilot and a ...
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1answer
499 views

How do you lean mixture using only the instruments on a C172 Skyhawk?

POH manuals always tells to use the voice of the engine as a reference. (Which complicates things a little bit since carbs and fuel injected planes have different "reaction times" for each cylinder) ...
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2answers
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How is crankcase ventilation handled in R-2800?

I just finished R-2800: P&W's Dependable Masterpiece and noticed there's no mention of a pump for crankcase ventilation. Is this handled by the oil scavenge pumps?
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2answers
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How do I estimate piston aircraft fuel efficiency?

Is there any way to figure out or calculate fuel consumption of piston engines for aircraft? I'm looking at different engines in a book, and while jet engines have useful values like thrust, bypass ...
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2answers
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Why is the fuel pump in the startup procedure for a Cessna 172?

I thought fuel pumps were reserved for fuel injected planes in startups and during critical flight phases for all planes? However. There are some X-Plane flight tutorials that tells us to use fuel ...
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3answers
2k views

How do carbureted and fuel injected engines compare in high altitude?

I couldn't find enough information on the internet for this topic. What I found can be paraphrased as: Carburetor means easy engine start while fuel injected means manual fuel start up and ...
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2answers
273 views

What modifications are required for automotive fuel STC?

What actual engine modifications are required to allow certificated piston engined general aviation aircraft to run automotive fuel under an FAA Supplemental Type Certificate (STC)?
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1answer
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Why do the Diamond DA-42 and DA-62 have a minimum fuel temperature requirement?

On the turbo diesel DA-42 and DA-62 aircraft there exists a minimum fuel temperature limitation where you may not start or operate the aircraft below that. Does anybody know why this is? It seems ...
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1answer
490 views

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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2answers
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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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2answers
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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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2answers
279 views

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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4answers
624 views

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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1answer
499 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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2answers
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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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1answer
267 views

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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4answers
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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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1answer
756 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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4answers
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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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1answer
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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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3answers
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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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2answers
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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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