53 votes
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What is this large engine doing on a B52?

Testbed Aircraft Cameos As a young engineer in the 1960s at Pratt & Whitney Aircraft (now UTC’s Pratt & Whitney) in East Hartford, Connecticut, I was involved (along with many others) ...
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  • 2,377
44 votes
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Why should you not turn in the direction of an inoperative engine?

The AvHerald comment is correct, you generally do not want to turn towards the dead engine. The aircraft will tend to turn (both yaw and bank) towards the dead engine due to asymmetric thrust, ...
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43 votes
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How many four-engine commercial passenger jetliner types are currently in use?

Well, the 3 points you make are easily demonstrable to be true, and also a fairly unique feature of all three if looked at side-by-side. The 747 is the only one with an obvious hump towards the front ...
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  • 25.1k
42 votes
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Do multi-engine jets need all engines with equal age to reduce asymmetry in thrust and fuel consumption arising out of deterioration?

It doesn't quite work that way. When an engine wears out it's rated thrust doesn't decline; its "ITT Margin" (or some similar phrase - basically its thermodynamic margin at takeoff) declines. When ...
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  • 103k
38 votes

Do turbine engines on multi-engine aircraft rotate in opposite directions to offset torque?

Torque is less of a problem due to the effective roll damping of a wing, but gyro effects and prop wash are important. Gyro effects first became an issue with rotary engines in WW I. A rotary engine ...
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34 votes
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Why do we never see high-bypass turbofan engines sharing the same nacelle on large airliners and similar aircraft?

Short answer It's the vastly different flow conditions from static to cruise which demand a separate placing of high-bypass-ratio jet engines. They would produce less thrust and more drag when paired....
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33 votes
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Why is rotating engines in opposite directions more important for a propeller-driven plane than a jet?

This is sort of explained in the linked question already. Specifically this answer (which I consider better than the accepted one above it) says: Today, high power propeller aircraft tend to use ...
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30 votes
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Why is the ball no longer centred in a multi-engine airplane with inoperable engine?

Asymmetric thrust means now you have more thrust on one side than the other. A yawing moment results. You want to balance this yawing moment in order to still fly straight. This means the airplane ...
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29 votes
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Taxiing with one engine: Is engine #1 always used or do they switch?

Airbus aircraft have 3 hydraulic systems (Green, Blue, Yellow). Green is pressurized by left engine, Yellow by right engine, and each one can be pressurized by the other using the PTU. In addition the ...
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28 votes
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What is a Vmc roll?

I'm sure someone else will come along and give you a better answer with illustrations and everything, but until then, here goes :) Multi engine aircraft usually have their engines off to either side ...
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26 votes

What is propeller / engine sync and how does it work?

I don't know how it is achieved, but here is the reason: If you have two sources of the same noise, with nearly the same frequency, the sum of both noises will be a noise of slowly increasing and ...
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24 votes
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Can anyone Identify this FLY FAIR seaplane?

That is a Sikorsky S-38B I am not sure about the registration. My guess is NC196H, but it is one out of this list: NC158H, NC159H, NC195H, NC196H, NC197H, NC198H, NC199H, See aircrafthistory.org.uk ...
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22 votes

What is this large engine doing on a B52?

The plane in the pictures is Boeing JB-52E -test plane. It used to test for instance the General Electric TF-39 engines for the C-5 Galaxy as it was under development
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  • 20.7k
21 votes

What is propeller / engine sync and how does it work?

On the Junkers Ju-52 the pilot had two little discs which rotated with the beat frequency between two engines. The upper left one would show the beat frequency between the left and the center engine, ...
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21 votes

What determines the direction of rotation for counter-rotating propellers?

Most twin-engine aircraft with counter-rotating propellers have the rotation set up so that the propellers are rotating inward towards the center at the tops of the propeller arc. This configuration ...
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  • 31.8k
19 votes

In which direction should a turn-back be made after an engine failure on a multi engined airplane after take off?

That depends on a lot of factors. Are you declaring an emergency? What altitude are you at what speed are you at when this happens etc? What kind of aircraft are you flying? Does it have enough ...
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17 votes

What is a Vmc roll?

It's more correct to say this is an unintended roll induced by flying at a speed below Vmc. Vmc (V=Velocity, mc = minimum controllable) is the minimum speed a multi-engine aircraft can remain in ...
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17 votes
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Can the four-engined Lockheed JetStar II fly on one engine?

I have 3000 hours in jetstar.... The answer is no... It will not fly on one... Two yes and you really don't need that much rudder.. In the simulator with two out I used to put the inboard operating ...
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16 votes
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Would in flight engine failure of the passenger jet be reported?

To certify any Commercial Jet Plane worthy of flying, a 2 engine plane must be able fly with just 1 engine running a 3 engine jet like the Lockheed L1011 or DC10 with just 1 a 4 ...
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  • 647
16 votes

Do airline pilots identify failed engines in the same way as light aircraft pilots?

Yes, the dead foot, dead engine does apply (but not as much as you might think), and, yes, airline pilots need to rely on their engine instruments in order to figure out which engine has failed, ...
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16 votes
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What is propeller / engine sync and how does it work?

According to Wikipedidea In aviation, propeller synchronization is a mechanism that automatically synchronizes all propellers of a multi-engine, propeller-driven aircraft so that they rotate at ...
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  • 95.9k
14 votes

Why do we never see high-bypass turbofan engines sharing the same nacelle on large airliners and similar aircraft?

A big part of this is probably related to maintenance, as you observed. Currently, engines are generally taken straight off of the pylon. If they were paired on a pylon, They would either have to be ...
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  • 69.7k
14 votes
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How does the range of a single- and twin-engine for small aircraft compare?

(Cessna 185 Skywagon and Cessna 340) See here for the major points: What are the pros and cons of single-engine vs. twin-engine? Regarding your specific question: Wouldn’t a single engine plane ...
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  • 120k
14 votes

What is the aircraft model used in the film "American Made"?

If you are talking about the one prevalent in this trailer its an Piper Aerostar 600. The tail number is legitimate and the full registration details for 164HH can be found here. Some of the movie ...
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  • 95.9k
13 votes

Why is the S-duct intake on the Tu-154 uniquely oblong?

This doesn't fully answer the question, but the B727-100 also had an oval engine intake. AIRLINERS magazine Sept/Oct 99 edition: "The oval shape inlet on the 727-100 series was changed to a ...
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  • 31.8k
13 votes

I am licensed as a Private Pilot, Airplane Multiengine Land, what do I need to do to be able to fly as PIC in a Single Engine Land aircraft?

No, you cannot. Just like an ASEL doesn't give you the ability to fly an AMEL, if you have an AMEL that doesn't give you ASEL privileges. Adding the ASEL shouldn't be that hard though, especially if ...
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  • 35.1k
12 votes
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Does the DC-3 have a prop sync?

Judging from this video, it does not have an automatic prop sync. When throttles are advanced you can hear the harmonic beat of the twin propeller blades, and during the climb the instructor seems to ...
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  • 57.7k
11 votes
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Can I log time in a Cri-Cri twin-engine aircraft?

What a positively delightful looking aircraft! I see no reason you couldn't log time in this as multi-engine time - it clearly has two engines, with two separate sets of controls (at least throttles, ...
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  • 67.2k
11 votes

Why isn't there a procedure for dual-engine failure in twin-engine airplanes?

There are. The Metroliner (SA227) has a dual flameout checklist. It's possible that the company I flew for developed their own and had it approved, but we DID have a checklist for that. I think ...
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11 votes
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Why would aircraft engines be mounted with "toe out"?

According to this source The engines were toed out slightly to improve engine-out handling; three tailfins were used to ensure that the aircraft could keep flying more or less straight if both ...
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