Questions tagged [cruise]
The section of flight between the after takeoff climb and landing approach.
71
questions
5
votes
3
answers
3k
views
Why is it that when autopilot is maintaining cruise, we don’t feel the changes when lift increases?
When we’re inside an aeroplane, when we’re in cruise, why is it that we don’t feel the changes in altitude, lift and the adjustments for example from the elevator on the plane as the weight is burned ...
- 87
-2
votes
1
answer
160
views
How is an airliner trimmed nose-down or up? [duplicate]
so when a plane is in cruise, it loses weight and then the weight begins to exceed lift.when this happens, the plane begins to climb.
My question is this please:
The plane would be trimmed up or down ...
- 87
1
vote
3
answers
105
views
How does drag change efficient cruise conditions?
If I have an aircraft, and I reduce the induced drag produced by it, does this mean I should operate it at a higher altitude and faster speed to take advantage of the drop in total drag, or slower at ...
15
votes
2
answers
4k
views
Does flying slower actually save fuel?
Following a discussion on travel.SE, I wonder: would flying more slowly actually save fuel?
I suppose that it would save fuel on a volume of fuel per flight hour basis, but the flight would end up ...
- 2,251
0
votes
3
answers
100
views
Does cruise speed depends on rate of climb?
If an aircraft wants to fly at a fixed cruise speed, will the rate of climb have any effect on that? For example, let's assume an aircraft has to fly at a cruise speed of 0.8 Mach. How will the rate ...
- 101
0
votes
2
answers
152
views
Does lift requirements change as fuel is burned? If so, how?
so when an aircraft flies in cruise, it burns weight and so what impact does this have in lift requirements?
Would there be a need to also deflect flaps to stay in cruise as fuel is burned?
— I’m ...
2
votes
1
answer
186
views
Is there any existing engine which can be converted to turbofan from turboshaft in mid flight?
I read about convertible engines. I want to know if there is any engine existing to meet up hover and cruise together.
- 101
0
votes
2
answers
189
views
Why isnt the structure of the aircraft affected by high true air speeds or high ground speeds?
Let's suppose that in Cruise flight I exceed the VNE in TAS or in ground speed, why isn't the structure of the aircraft affected by the high speeds?
I am sorry for my english, I am not a native ...
- 11
12
votes
5
answers
8k
views
Why do missiles typically have cylindrical fuselage and not a fuselage that generates more lift?
For example, Tomahawk Cruise Missile, or Harpoon anti-ship missile. They fly straight and level for the most part of their flight regime. I think if they had a fuselage optimised for level flight then ...
- 319
2
votes
3
answers
276
views
Will a heavier aircraft be more efficient at high speeds(cruise)? [closed]
Since heavier aircraft have more mass and inertia, they will have less drag because it will be easier for them to push through the air so does that mean that we can achieve the same cruise speed with ...
- 31
15
votes
2
answers
5k
views
Do airliners reduce their angle of attack to maintain lift = weight as fuel burns off during cruise?
For an aircraft to remain in level flight, it must generate lift force that is exactly equivalent to its weight. However, modern airliners lose a lot of weight when they are in cruise flight in the ...
- 944
1
vote
1
answer
159
views
How to compute the mass flow rate for a turboprop at cruise given the static sea level value?
I am trying to obtain the mass flow rate of the Allison T56-A-15 used on the C130H at cruising altitude (so as to solve the Joule-Brayton cycle at cruising altitude). I know from "Turboshaft, ...
- 11
0
votes
0
answers
83
views
What is the effect of aspect ratio on cruise velocity?
Does the Aspect ratio affect the Maximum cruise velocity please?
I was thinking it wouldn’t as Aspect ratio= b^2/S.
If I wanted to go quicker I could just increase my span and decrease S?
4
votes
1
answer
4k
views
Why do B787 Dreamliners more often fly at 42,975 ft rather than at 43,000, according to flightradar24?
The A350 and the B787 are the only passenger airliners that can be seen cruising as high as 43,000 ft on flightradar24 (with the exception of a B747 I once saw). However, the B787 is more often found ...
- 997
18
votes
5
answers
5k
views
Would an airliner climb higher late in the flight because of the consumed fuel (lighter airplane) to save more fuel?
Some people said airplanes would fly higher in the late period of each flight, because the fuel is consumed, and the airplane is lighter. Higher altitude and less dense air is enough to support the ...
- 351
1
vote
1
answer
291
views
Does the optimum LRC speed increase or decrease as the GW of the aircraft decreases during a long range flight?
I do not know what defines the optimum LRC speed for each aircraft, aeronautically speaking.
I suspect it has something to do with optimum AoA but even then I am not sure if the LRC speed should ...
- 477
14
votes
2
answers
6k
views
Why are planes required to cruise at round flight levels only above 18000 ft of altitude?
AFAIK, planes flying at up to FL180 (18,000 ft pressure altitude) are allowed to fly at both round and semi-round altitudes (e.g. 15,000 ft or 15,500 ft). Planes flying above FL180 must fly at a round ...
- 533
6
votes
1
answer
1k
views
How to most likely get a flight that will go above 40,000 ft?
I wonder if there are passenger flights that would reach cruise altitudes higher than 40,000 ft (i.e. reach 41,000 ft for instance) more likely than others. It also depends on the plane of course, but ...
- 533
1
vote
2
answers
524
views
Do most commercial jets cruise at constant altitude/speed?
The weight changes throughout, so this means aerodynamics efficiency changes to maintain constant speed and altitude. Is this how most commercial jets cruise?
- 692
0
votes
1
answer
731
views
Aircraft thrust calculation
I had a question regarding thrust calculation for an aircraft during cruise. For an aircraft flying at a constant cruise altitude and a constant Mach number (level unaccelerated flight), what exactly ...
0
votes
1
answer
147
views
Descent of Light attack aircraft to loiter altitude
How do Light Attack Aircraft (LAA) such as the Embraer Super Tucano descend from their cruise altitude to their loiter altitude to be on-station above ground troops? I want to know the way these ...
- 461
3
votes
2
answers
456
views
Optimizing the airplane for best cruising altitude and velocity
In the conceptual phase of the design, I am optimizing various entities of an airplane for the best cruising altitude and speed to reduce the cost, which also includes MTOW and fuel weight. Consider a ...
- 461
-6
votes
1
answer
303
views
Relation between weight of the aircraft and mach number [closed]
Is there any formula that relates weight of the aircraft with mach number?
6
votes
1
answer
4k
views
How is the Dash 8 Q400 so fast?
The Q400 has a cruise speed of 360kts, and on flightradar24 most Q400s that I looked at reached similar speeds during cruise. The ATR 72 has similar specifications yet only flies at 280kts. I'm ...
- 611
1
vote
2
answers
3k
views
How much thrust is produced on an A320 at takeoff and during cruise?
Where can you get the drag polar of the A320 at cruise and TakeOff?
- 11
7
votes
1
answer
1k
views
Based on this fuel flow chart, why isn't it more optimum to remain at an intermediate altitude rather than climbing?
I am having a bit of confusing as to why people say planes gets more efficient as they fly higher. Because on a typical long haul flight the Fuel Flow of the aircraft will obviously be much more that ...
- 71
7
votes
3
answers
4k
views
Do pilots keep light in the cockpit during long night flights?
During long times of the cruise flight, is the internal light normally switched on or off inside the cockpit?
Knowing it is generally dark in the night would make a smartphone-based night time logger ...
- 12k
2
votes
1
answer
1k
views
Relationship between wing aspect ratio and speed [duplicate]
For some reason, I cannot find a relatively straightforward source online which discusses the relationship of wing aspect ratio and how it affects speeds of an aircraft.
Specifically, is there a ...
- 21
2
votes
1
answer
1k
views
Why is the thrust-specific fuel consumption much worse for high bypass turbofans at cruise?
General Electric GE90
Takeoff: 0.278 lb/lbf/h (28.3 kg/kN/h)
Cruise: 0.545 lb/lbf/h (55.6 kg/kN/h)
Source: https://en.wikipedia.org/wiki/General_Electric_GE90#Specifications
I assume this is typical ...
- 3,524
24
votes
4
answers
6k
views
Why are heavy flaps better than just a bigger wing?
Flaps increase lift during landing and T/O. But when retracted, they do nothing. The space needed to stow the common fowler flaps can't be used for anything else - fuel or structure. Extended flaps ...
- 3,524
4
votes
1
answer
3k
views
Cruise Mach Number less or more than Critical Mach Number
Do commercial airplanes cruise at Mach number higher than the critical Mach number? And what is the critical Mach number of airplanes like B777 or A330?
- 461
2
votes
2
answers
997
views
What is the main reason why cruise flight in the transition layer is prohibited?
What is the main reason why cruise flight in the transition layer is prohibited? For example if we have a separation of 1000 ft between transition altitude and transition level, why should we not ...
- 23
1
vote
3
answers
785
views
How long is a climb leg in a step-climb cruise flight segment allowed to take, according to regulations (FAA/EASA)?
I am working on a trajectory optimisation program for commercial, large aircraft, in which I want to incorporate realistic air traffic control regulations. One of the constraints I want to incorporate ...
- 113
17
votes
5
answers
7k
views
How do planes maintain constant speeds at cruise altitudes?
I'm a noob so pardon my ignorance. So my understanding is that as the plane gets lighter during the flight, its mass reduces therefore reducing the lift needed to maintain the altitude. At those ...
0
votes
1
answer
528
views
Tiny margin between VFR cruise and over Class C?
Our class C airspace at KRDU has a 4400 ceiling. If I fly Westbound above the airspace at VFR cruise, I'm expected to be at 4500. Since this is a tiny margin and I don't want to bust into the airspace ...
- 433
1
vote
1
answer
2k
views
What is nominal n1 and fuel flow behavior during cruise climb?
For a commuter airliner (e.g. 737) performing a cruise climb (step climb) at a constant Mach, how should n1 and fuel flow behave?
I know that fuel flow should decrease with altitude (air fuel ratio).
...
- 123
3
votes
1
answer
1k
views
Does the Enroute Phase begin at a 30NM distance from the departure airport?
ICAO's Doc 8168 Volume II ("Aircraft Operations") states:
Part III "Performance-Based Navigation Procedures"
Section 1 "Underlying Principles"
Chapter 1 "RNAV ...
- 1,853
30
votes
6
answers
5k
views
Why cruise at 7000' in an A319?
I was on a flight from Philadelphia (KPHL) to Boston (KBOS), after some delay and some change of route due to weather, the captain announced that we will be cruising at 7000' due to delays in the area....
- 452
14
votes
4
answers
6k
views
How do planes know what altitude they're cruising at?
I know that when planes enter the aerodome containing the airfield of destination, the ATIS will tell them an altimeter setting so the system knows how to calculate their altitude above their field; ...
- 340
2
votes
1
answer
94
views
Learn in-depth about airplane operations [closed]
Currently seeking a book or manual that teaches a civilian how a cargo aircraft operates and what it's pilots do, say a 787. Preferably a high-level overview at a per flight phase:
Pre-flight: Flight ...
- 225
11
votes
1
answer
625
views
Is there research suggesting that VFR cruise altitude rules improve safety?
In the United States, 14 CFR 91.159 prescribes cruising altitudes for level flight under VFR:
(a) When operating below 18,000 feet MSL and
(1) On a magnetic course of zero degrees ...
- 5,761
0
votes
2
answers
522
views
Why is the normal operating airspeed so much lower than the cruise speed in this table?
I need to work with the following table. I'm interested in vMO which I assume I can simply obtain from converting MMO to vMO through $M = v/ \sqrt{1.4 * 287 * T}$. (Is that correct?)
However, I ...
- 823
1
vote
1
answer
698
views
Why would a plane drop 14.000 ft mid flight?
Just noticed American Airlines flight 221 dropped 14.000 ft mid flight today. Curious, what could have caused this?
Here are the flight details.
- 21
6
votes
3
answers
450
views
Can airplane performance be increased by cruising "on step"?
Old timers swear aircraft performance can be increased by getting an aircraft "on step" similar to how boats are operated.
They claimed a couple extra miles per hour (airspeed was in MPH then) were ...
- 11.3k
4
votes
2
answers
2k
views
What is the throttle setting of a piston aircraft during cruise?
I am learning to fly nowadays, I am sorry if this sounds like a dump question.
What is the throttle setting of an aircraft during cruise flight?
After stabilizing the flight after climb do i need to ...
- 171
5
votes
1
answer
1k
views
What happens if full thrust is applied at cruise altitude for 5-10 minutes on a 787?
What happens when you apply full throttle to the engines of a Boeing 787 at cruise altitude for 5-10 minutes?
Other than wasting fuel, what maximum speeds are reached?
Does that pose any danger or ...
- 8,509
1
vote
1
answer
975
views
What VFR cruising altitude should be flown to the west below 4500 feet?
This is similar question to this question, but different scenario.
Let me describe the situation:
I am at KDYL in class G airspace. Accroding to ATIS the clouds are at 4700 scattered. I am going to ...
- 351
0
votes
1
answer
330
views
How do single GA pilots prevent boredom during long flights? [duplicate]
My question somehow relates to this question asking about how pilots cope with boredom, but now the scenario is not the typical airliner configuaration with two pilots, but with only one. I'm thinking ...
- 4,692
7
votes
2
answers
14k
views
What throttle setting does an airliner use while cruising?
As a passenger, I have always felt like the engine are not kept at take-off thrust/full throttle a few (tens of) seconds after take-off, and so for obvious reasons as fuel efficiency, engine wear ...
- 400
2
votes
2
answers
4k
views
What is the Fuel-Oxygen ratio for a large turbofan at cruise conditions?
What is the Fuel-Oxygen ratio (by mass) for a large turbofan at cruise conditions?
In order to be concrete, I'll just pick an engine at random. I pick the GE90-115B. Okay it's not really random, it'...
- 17.6k