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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2answers
99 views

What determines the actual crankshaft rotation RPM speed of a piston engine?

(I know how cylinders work and how they transfer the power to the crankshaft rotation, I also know there is Clutch or Fluid-coupling to make sure the sudden "stuck" or "stop" in ...
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1answer
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Why oil pressure decreases when coarsen the pitch during run-up?

During run-up checks, we set the Throttle such a manner that RPM IS 2000 then we do run-up checks Magneto check 2.prop check Notice RPM drop MAP increases Oil pressure decreases Why does MAP ...
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2answers
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What is vapor lock?

Vapor lock occurs in piston engines especially during summers.. before starting engine we prime it and the engine starts but as soon as we reduce it to near idle or just above idle, engine tends to ...
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1answer
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Why does RPM increase when you lean the mixture in constant speed propeller engine?

In constant speed propeller aircraft like Diamond star DA-40, during run-up checks the AFM mentioned to increase throttle to increase RPM to 2000 and then do magneto check then rpm check then mixture ...
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1answer
189 views

How much drag is actually caused by open cowl flaps?

I am modelling the Cessna 210 for FlightGear, which has cowl flaps. I want the model to be as realistic as possible, and so, I want to know: how much drag do cowl flaps produce ? I could not find any ...
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1answer
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What should I look for / check during an oil change?

Piston aircraft engines require regular oil changes, and at least in the US it's something the FARs allow an owner with a private pilot certificate to do. What are some of the things I should look ...
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6answers
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Why have propeller engines never been mounted on the tail in production transport aircraft?

Recently, Embraer teased this concept. Unlike jet engines, I have never heard of a production airliner or executive aircraft that mounted propellers on the tail like this. From the source: the new ...
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Engine Bearings Damage in Radial Engines

Studying the P47's dive performance in DCS, I noticed how it's easy to damage the engine bearings if you windmill the prop at high speed. Doing some research, I discovered that all radial engines are ...
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1answer
240 views

What is the metal sheet in front of the engine called on a Cessna 182 or similar?

I need to know the name of that metal sheet covering the front of the engine in small Cessnas (specifically the Cessna 182), just behind the propeller. I mean the one where the cowl plugs are put into:...
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8answers
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What is the theoretical maximum RPM of a typical aircraft piston engine?

Given a standard 6-cylinder, direct-drive, horizontally-opposed engine like the Continental IO-550 or Lycoming IO-540, the maximum RPM for those engines is 2700 RPM. That's due to keeping the ...
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1answer
75 views

BHP increases with Altitude

Searching on internet, I found some performance charts of the Merlin Engine BHP output: As you can see there is an increase in BHP,(mainting a constant Boost Setting), until reaching the critical ...
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1answer
96 views

Why is the RPM limit on a Lycoming IO-540 different in the -C and -D versions?

On a Lycoming IO-540, it seems there is a Max RPM difference between the -C and -D versions (and thus a max HP difference too). Does anybody know what is different in the engines that causes this, or ...
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1answer
8k views

How to calculate the thrust of a piston or turboprop engine? [duplicate]

This spawns from a related question. Propeller-drive engines (piston/turboprops) seem to always list their output in horsepower or kilowatts, which are units of power. I want to know the engine's ...
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Can I assume that AVGAS can be used without any problem when the engine manual suggests RON 95 or higher?

Can AVGAS 100 LL be used without any problem in Rotax 912i engine which suggests a fuel with RON 95 or higher? What would be the advantages of using AVGAS over unleaded RON 95 gasoline?
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Are there any spark plug modifications that prevent fouling?

Today, the plane I had, failed the Run up because the magneto test failed. One of the spark plugs fouled out. Other than making sure the engine is properly leaned out (even then spark plugs in a plane ...
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1answer
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What are the consequences of pumping the throttle in an carburetor piston engine airplane during start?

I have seen an expert commercial pilot pumping the throttle during start for a Cessna 152 and ever since I thought that was ok to do so, but recently studying for ATPL I read about that these ...
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1answer
932 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
330 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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Why does using carburetor heat increase fuel consumption?

As written above, why does using carburetor heat increase fuel consumption? Because I found such information in a few SOPs for piston airplanes and I do not understand why does it happen
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3answers
993 views

Why do piston engines have a lower fuel consumption with higher temperatures?

It is very common to find in the AFM/POH, Section 5 of most piston engine airplanes (C152, C172, PA28, BE76, etc) charts that indicate the fuel consumption for cruise/economy power settings. You ...
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2answers
101 views

Why is a reciprocating engine air intake a reverse bell shape? [duplicate]

Why would this inlet for the induction system get wider as the air approaches the filter? What net effect does this have on intake pressure, and how would an inlet that starts wide and then narrows ...
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What is the proper procedure for a piston engine fire on the ground (e.g. during engine starting)?

I am wondering what is the correct sequence of action if there is a fire e.g. during engine starting. Of course I know that there are emergency procedures in each AFM and every single plane is ...
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Was Stringfellow's 1848-1868 motor a revolutionary aviation engine or just a useless low efficiency toy which never powered a flying model plane? [closed]

I took a look at the 1848 Stringfellow's aviation steam engine and I do not really understand how it was capable to power a model plane in horizontal flight as long as the motor itself was just an ...
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1answer
171 views

Can a single seater airplane fly with 50 lbs of thrust

An airplane with 10 sq meters of wing five meters fuselage and including one person. can it fly with 50 lbs of thrust? And the max weight is 400 lbs
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Why don't all cylinders have priming lines?

Questions about the primer for carburetor engines. Why does the primer only spray fuel to three (sometimes just one) of four cylinders. (Like Piper Cherokee or Seminole) And is it true that priming ...
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1answer
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Can we get 0:40 thrust to weight ratio from three small engines

Because I have an engine of 13 hp four stroke 1 cylinder that pulls about 0:20 T/W ratio. and is it possible to multiply the thrust by two? Using two more small engines which is 6.5 hp each on the ...
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1answer
108 views

Are return springs on a carburetor throttle mandatory or not?

In many GA aeroplanes throttle control is connected mechanically to the throttle of carburetor via a cable. I read in some AFMs that in case of a cable failure, return springs will open the throttle ...
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1answer
262 views

Why not use the engine of a model aircraft for other purpose?

I was reading the DLE-120 engine User Manual and saw this sentence: This engine was designed for use in a model aircraft. Do not attempt to use it for any other purpose. Why? Why not use the engine ...
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9answers
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Why increase the number of cylinders in an engine instead of increasing their volume?

I've been reading about WW2 planes lately. Some of them have 12 or even more pistons in their engines. But if your goal is to increase power, why would you add more pistons instead of simply ...
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What does this formulation mean?

Just was reading this manual => DLE-120 engine User Manual On this page (pg 4), I saw this formulation: What does it mean? How is the 30:1 ratio calculated? What does "fl oz" mean? What ...
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1answer
3k views

What does "spark plugs appear yellow at the ignition point" mean?

I was reading the DLE-120 engine User Manual and saw this paragraph: Caution: Running the engine with a lean fuel mixture will cause the engine to overheat and burn the electrode of the spark plugs. ...
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1answer
108 views

What's for the "smoke fittings" in this muffler?

Just was reading this manaul => DLE-120 engine User Manual In this page (pg 4), saw this part: What's for the "smoke fittings" or "fuel tubing"in this muffler?
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1answer
160 views

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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4answers
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Why does enriching the mixture ratio beyond stoichiometry give more power?

In other words, in a piston engine, the best-power mixture is richer than that producing the EGT peak that signals stoichiometric combustion. Why is that, physically?
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1answer
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Why do propellors have white markings on their tips? [duplicate]

Why do propellors have white markings on their tips? Here are a couple of examples:
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4answers
29k views

In which phases of flight should the carb heat be turned on?

I have about 200 flight hours in a fuel-injected C172. I have just jointly bought a C152 with a carburetor and I am getting used to using the carb heat. I am scared whenever I hear stories about ...
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1answer
626 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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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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0answers
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Why can't you turn off GA aircraft like a car? [duplicate]

The Cessna 172S Aircraft Flight Manual states the following for securing airplane after commencing a flight: SECURING AIRPLANE Parking Brake -- SET. Electrical Equipment, Autopilot (if installed) -- ...
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3answers
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Why do we take off with maximum power settings?

In most GA prop airplanes, take-off is executed with full throttle and high rpm. The usual reasoning is that this way, we leave the first few hundred feet, where failures are most severe, behind as ...
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Are there any pressurized piston-engine aircraft?

Are there any pressurized piston engine-powered aircraft? Or does pressurization require a turboprop or jet?
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Carbureted Rotax engines have no mixture control, how do they handle less dense air?

Rotax engines have no mixture control, yet they don't seem to have any more problems than other engines at altitude. How do they handle the lower air density in order to not get a too rich a mixture?
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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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1answer
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Identify this USAAF biplane

I have been unable to match this USAAF biplane with a similar photo mainly due to the cockpit canopy. I've found no other like it. I believe the photo was taken at Madison, WI or Chicago, IL in the ...
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2answers
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Whenever I hear a plane throttling down quickly, what is happening visually?

I am completely blind and have heard this several times when I was at air shows. Then my friend sent me this recording of a crop duster spraying the fields, and I heard the same type of sound. It ...
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1answer
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Can coaxial rotors be mounted on a piston engine like the Lycoming O-320?

What are the drawbacks of this compared to coaxial configuration with a turboshaft engine?
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Why is the maximum endurance for a piston aircraft at sea level?

The Canadian Flight Training Manual stated this when talking about maximum endurance: For reciprocating engines, maximum endurance is achieved at sea level. The book does not explain further as to ...
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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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1answer
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Does a constant speed prop deliver max speed at max manifold pressure and max RPM?

I was reading a discussion in flight simulator forum and I found this statement: Ignoring the issue of engine overheating, max MAP and max RPM is the best thing for max speed Do you agree with that? ...
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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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