Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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.

34
votes
2answers
9k views

How often should an engine be run, to stay mechanically sound?

It's winter time and many light aircraft are sitting idle. This can be detrimental to an engine's health. What is a good rule of thumb for how often a piston engine should be exercised, and for how ...
23
votes
6answers
6k views

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 ...
0
votes
2answers
125 views

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?
3
votes
1answer
226 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 ...
5
votes
1answer
233 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 ...
3
votes
4answers
209 views

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 ...
6
votes
4answers
223 views

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 ...
32
votes
14answers
59k views

Why don't small planes use turbine (turboprop) engines?

Turboprop engines are more fuel efficient1, lighter for the same power, mechanically simpler and consequently more reliable. They are also slightly easier to operate (no need to fiddle with mixture) ...
4
votes
1answer
231 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 ...
13
votes
4answers
4k views

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 ...
5
votes
1answer
211 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 ...
6
votes
2answers
8k views

Are there any pressurized piston-engine aircraft?

Are there any pressurized piston engine-powered aircraft? Or does pressurization require a turboprop or jet?
8
votes
2answers
2k views

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 ...
18
votes
3answers
30k views

How does the mixture of an engine affect the engine's operation?

I know that in most piston aircraft that there is a mixture control for the engine. My question is, how does the mixture control affect the engine's operation and what type of situations dictate a ...
1
vote
1answer
131 views

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 ...
5
votes
2answers
200 views

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 ...
16
votes
3answers
3k views

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 ...
2
votes
2answers
192 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 ...
0
votes
3answers
217 views

Is there a system where plane/heli auto adjusts prop pitch/mixture?

This one is simple: is there a system that automatically adjusts things such as: Mixture (I Am bored of listening for engine sounds) Prop Pitch (I Hate auto adjusting "gears") So I can ...
-6
votes
2answers
736 views

Why are car engines not used for planes? [closed]

I found this picture of a 1/2 VW Bug pan air cooled engine in a plane. Source What other air cooled car engines work well in a plane?
5
votes
2answers
126 views

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 ...
4
votes
3answers
439 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), ...
8
votes
1answer
276 views

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....
10
votes
5answers
2k views

Why do the Lycoming HIO-360 A1A and IO-360 engines produce different power?

I have just acquired an aerobatic aircraft fitted with a Lycoming HIO-360 A1A. Reading the specs on the engine I see it has the higher (8.7:1) compression of the 200hp IO-360 engines, which seem ...
36
votes
9answers
18k views

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 ...
8
votes
2answers
268 views

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 ...
1
vote
1answer
117 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 ...
5
votes
2answers
1k views

How does the safety record of the twin piston Diamond DA-42 compare to the single piston DA-40?

Its fairly well known that the Diamond DA-40 has one of the smallest fatality rates of any GA plane. The Diamond DA-42 is a twin engine aircraft with a very similar design to the DA-40. Now, it has ...
1
vote
1answer
588 views

How do turbofans and piston-engines compare in terms of maintenance costs?

I want to compare piston engines and turbofans on a maintenance basis. Let's say both engines are capable of 100 kN of thrust. Let's say both engines fly for 10,000 hours. Over that time, what kind ...
3
votes
2answers
257 views

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 ?
1
vote
1answer
141 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: ...
19
votes
5answers
31k views

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 ...
0
votes
1answer
130 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 ...
9
votes
6answers
11k views

Why is full carb heat recommended when reducing power below normal setting?

In my first flight lesson today, my instructor asked me to apply full carburetor heat when we had to reduce power to 1900 RPM in our Cessna 152. I was surprised by this as I didn't remember learning ...
1
vote
1answer
170 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 ...
-1
votes
1answer
433 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.
4
votes
1answer
400 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?
39
votes
5answers
77k views

What are the differences between fuel types (comparing with vehicles)?

I find it funny that at gas stations, generally you can purchase "regular" gasoline (in various octane levels) or diesel. At airports, generally you can purchase 100LL avgas or Jet-A. Can you compare ...
6
votes
3answers
398 views

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?
-1
votes
1answer
343 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 ...
-1
votes
1answer
81 views

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.
13
votes
1answer
2k views

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?
16
votes
4answers
19k views

What are the advantages/disadvantages of diesel/Jet A-1 piston engine?

Some GA aircraft, notably the DA40/DA42, are equipped with piston engines that use Jet A-1 and/or automotive-grade diesel instead of aviation gas (avgas). An example of such engine is the Austro ...
26
votes
3answers
5k views

Why do aircraft piston engines consume so much oil?

This question is related to single/twin piston engine aircraft. After flying in a Cessna 152 and a Piper Dakota I have noticed that they both consume a lot of oil. Oil check is an integral part of the ...
31
votes
4answers
5k views

Why isn't the APU a standard diesel generator?

Why isn't the APU a standard diesel generator? Jet-A and diesel are interchangeable (with the addition of a lubricant). So why not use a cheaper piston engine as opposed to a jet turbine? V.S.
2
votes
2answers
205 views

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 ...
21
votes
3answers
10k views

Why are propeller engines uncommon on airliners?

My experience in aviation is essentially zero, but looking at Wikipedia it seems like the Tu-95 Bear offers high subsonic speed and extreme range. I assume that turboprop engines are more fuel ...
19
votes
3answers
4k views

Why the lack of faster piston-powered planes?

There aren't very many fast piston airplanes in production. By "fast" I mean, if you look back in the early to mid 20th century, before turbines won out, there were lots of piston airplanes in ...
1
vote
2answers
163 views

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 ...
15
votes
2answers
5k views

Why is the magneto drop check done at 1700 RPM?

In our Cessna 152, we carry out the mag drop check at 1700 RPM, following the POH. My question is why it is done at 1700 RPM? What will happen If I check it at 2000 RPM or less than 1700 RPM? And if I ...