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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1answer
170 views

What are the reasons for this radial piston engine shut down procedure?

In a radial piston engine, before the engine is shut down the rpm is brought to a considerable high power setting of approximately 1950 rpm. This is to burn the unburnt carbon in the spark plugs. Are ...
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6answers
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Why does manifold pressure increase with power?

Whilst writing an answer to this question, I remembered something I don't really understand. The partial vacuum in the inlet manifold is caused by the piston descending with the inlet valve open ...
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Why does exhaust flow inwards through a radial turbocharger?

In a radial compressor, the air enters centrally and passes outwards, aided by centrifugal force. But, as the diagram shows, in piston-engine superchargers the driving exhaust gas flows inwards ...
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Can the plane Celera 500L be eight times more fuel efficient than a jet of similar size and capacity?

Celera 500L (see Otto Aviation site for more details) is a plane with a single propeller powered by a piston diesel engine. The constructor claims it is 8 times more fuel efficient than a jet of about ...
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498 views

What can cause the engine temperature to be high in piston engines?

What can cause the engine temperature to be high in piston engine aircraft?
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1answer
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What is the problem if the temperature of the oil and heads of cylinders is too high?

What is the problem if the temperature of the oil and heads of cylinders is too high? What's the fault in piston engines?
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Starting on the left magneto only - why?

I had been flying a PA-28 Archer III for quite a few months before I sat down to properly read through the POH. Something stood out to me about the starting procedure (emphasis mine) Open the ...
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6answers
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Why should some piston engines not be run lean of peak?

Leaving aside the claimed pros and cons of lean-of-peak (LOP) vs. rich-of-peak (ROP), the C172S Lycoming IO-360-L2A handbook I have says "Continuous operation at mixture settings lean of peak EGT is ...
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0answers
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Is there a standard on-board diagnostics protocol for FADEC aviation piston engines?

Almost any car engine manufactured since 1997 will have on-board diagnostics, either the OBD1 or more recently the OBD2 standard which provides a standard for protocols, standard message codes and a ...
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1answer
124 views

What is the difference between Full Throttle Height and Critical Altitude?

My understanding is that "critical altitude" is the density altitude at which the wastegate on a turbocharged engine is fully closed, so any climb will result in a decrease in manifold ...
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1answer
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Why am I getting unusually high CHT on ground operations on one engine in a Seneca II?

Aircraft had sat for 3 months, and on startup the right engine CHT (Cylinder Head Temperature) was climbing noticeably higher than the left. After taxiing and run up CHT was near top of green. Redline ...
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What may be the cause of hot start problems in a Lycoming fuel injected engine?

Cherokee Six, 32-300 1969. Lycoming engine is fuel injected with 450 SMOH. Cold starts are easy: 1/2" throttle, full rich, fuel pump on and hit starter after fuel flow starts. Runs great once running. ...
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2answers
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How does engine primer work?

Does anyone have good resources on how piston-engine primers work? Looking for literature, schematics, or better yet, videos. I was told that in carburetor engines, it bypasses the carburetor and goes ...
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Is there an STC for converting the Continental O-470-R to a fuel injected engine?

Is there an STC for converting the Continental O-470-R to a fuel injected engine without making any other changes?
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3answers
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Why can we not use full throttle in a C172 when cruising at lower altitudes?

My flight training manual (FTM) says that at low altitudes we throttle back our trainers in order to not exceed recommended power settings. But why is that? Is the air close to sea level just too ...
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4answers
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Why hasn’t the Wankel rotary engine seen more use in aircraft?

The Wankel rotary engine seems to have several advantages over traditional reciprocating cylinder-and-piston designs. In general, they have a much higher power-to-weight ratio, less vibration, and ...
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2answers
169 views

Why, during a magneto check, does manifold pressure increase as RPM decreases?

When performing a magneto check or exercising the propeller prior to take off (constant speed propeller), you notice that as the rpm drops the manifold pressure rises slightly. Why does the manifold ...
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1answer
317 views

What is this part on a Cessna 172 engine?

Can any one tell me what this tube with the red is? This is a photo of a 1977 Cessna 172 engine. Looks like the tube is directly connected to the top of the crankshaft.
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1answer
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Why would a C150's tachometer fluctuate?

Why does a Cessna 150 aircraft tachometer fluctuate between a specific rpm between 800 and 1100 rpm? The idle rpm of the aircraft is 800 rpm.
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3answers
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Why do aircraft piston engines require priming?

Aircraft piston engines generally require priming, but automobile engines don't seem to need it. Why doesn't cranking the engine with the starter pull in fuel mixture that would ignite without help of ...
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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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1answer
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What appears on EGT Gauge if the mixture is rich or lean?

I have some questions on interpreting Exhaust Gas Temperature (EGT) readings. Can you give me some input on: What appears on EGT Gauge if the mixture is lean or rich? what is the normal range, ...
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2answers
206 views

Could abrupt flight controls input cause damage in these circumstances?

I went flying yesterday with a friend in my 1972 Grumman AA-5. She's a good copilot for someone who doesn't know much about flying. I showed her how you can pitch up and down, cause 0G, and float, ...
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6answers
297 views

Would a piston or turbine engine be best suited for a small UAV flying 8000miles?

I am trying to devise a concept that would airdrop medical supplies around remote regions of Africa: vaccines, medicine, blood... etc. I image the payload would be anywhere between 1-2 ton. I think a ...
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1answer
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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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5answers
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C-152 carb heat on before landing in hot weather?

I know the POH for the C-152 explicitly states carb heat should be applied before landing. I fly in a tropical country where temperature is at 30°C on average on the ground, twice the standard temp. ...
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1answer
214 views

Does the DA-42 automatically lean to clean fouled spark plugs?

The DA-42 has an automatic run-up method. Specifically, the pilot in command is to hold two buttons (one for each engine) until the run-up is complete. Since the DA-42 has no manual mixture control, ...
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1answer
493 views

Purpose of CHT drop in piston engine shutdown procedures? [duplicate]

One of the items in the helicopter Robinson R22 (and possibly other piston engined aircraft) shutdown procedure is to wait for the Cylinder Head Temperature to drop to a lower temperature. What is the ...
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2answers
267 views

What notification am I required to give when starting an engine?

This question is related to a single-engined piston-powered airplane. I was at a small airport. I noticed another plane parked behind mine. The pilot/owner was in the process of covering up his plane....
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3answers
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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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2answers
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Does it ever happen that increasing the prop RPM without moving the throttle actually decreases the thrust and power delivered to the airframe?

A) In an airplane with a piston engine and a constant-speed prop, flying at some given airspeed with the manifold pressure and RPMs in a typical cruise configuration, would it ever happen that ...
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29 views

What are examples of power-available and thrust-available curves for piston and turboprop engines, with constant-speed propellers in each case?

Considering the actual thrust or power delivered by the prop to the airframe, what are examples of power-available and thrust-available curves for piston and turboprop engines, with constant-speed ...
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1answer
810 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
33 views

Considering a piston engined aircraft, what resistance pressure would be generated within its engine bay against its cooling intake?

Consider a piston engine with all its coolers and components within an aircraft engine bay. To cool this engine, cooling intakes are positioned facing the direction of flight. Now, the condition at ...
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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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3answers
279 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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4answers
820 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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2answers
120 views

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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What causes a run-away propeller?

I've never understood this, why can't you just idle the engine and let it slow down?
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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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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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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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What is the aircraft model used in the film “American Made”?

In American Made, what is the model of the white airplane that the CIA presents to Barry Seal (played by Tom Cruise)? He says something along the lines of "the fastest piston twin". Are those ...
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2answers
114 views

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
1k views

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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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 ...
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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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1answer
594 views

Where to find information on the Daimler-Benz 606/610?

There seems to be relatively little information regarding either of these engines on the web. Anyone have an idea where I can find more info?

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