# All Questions

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### wave drag: Lift coefficient in Korn's Equation

I have been using the Korn equation: $$M_c = \frac{0.95}{cos(\lambda)}-\frac{t/c}{cos(\lambda)^2}-\frac{C_L}{10cos(\lambda)^3}-\sqrt[3]{\frac{0.1}{80}}$$ to estimate the critical mach number of a ...
66 views

### Why B737 CFM56 engine sounds like heavy wind sound at Throttling up?

14:14 ~ 14:21 : Throttle Up (with heavy wind sound 14:22 ~ 14:23 : Engine reached certain %, and no heavy wind sound 14:23 ~ : Throttle Up (with heavy wind sound) I always wonder why only B737NG with ...
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229 views

### How and when are cockpits cleaned?

It's well known that cleaning the cabin of an airliner in the short time it is on the ground can be a challenging task for the cleaning crew. But what about the best seats in the plane, the cockpits? ...
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236 views

### F15 Startup Intake drop

So I’m aware that the F15 has intake Ramps that adjust to airspeed and AOA, in order to ensure that the airflow is entering the engine smoothly and not too fast. But why does the system drop the first ...
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74 views

### Questions regarding Non-precision Localiser approach (KSEE LOC-D Approach)

Scenario Say we are doing some practice approaches into KSEE on the LOC-D approach. We are just southwest of the field and ATC/CFII says to climb to 5500 direct to BARET, cross BARET 5500 cleared for ...
193 views

### Name of this part of jet engine inlet

I can't find any name of it. I see it on some gas turbines but not all of them. Edit: Found them, they are called struts.
109 views

### In a straight and level flight if thrust is equal to drag how is aircraft moving forward?

If two forces are equal and acting in opposite direction should not the object remain stationary. Is there an excess thrust which actually pushes the aircraft forward ?
1 vote
179 views

### How do fighter jets maintain control while wings are perpendicular to airflow direction?

In my understanding, a plane stays stable and "straight", largely because the control surfaces such as the tail fins keep it stable by applying force in the opposite direction of any ...
113 views

### What can happen if everyone congregates at the back of a parked plane? [duplicate]

On a recent flight on an A320, after landing, when parked up at the gate, the cabin crew announced something along the lines of "Stairs will be at the front, please do not congregate at the back ...
• 13.6k
71 views

### Do Blended Wing Bodies produce more induced drag compared to a conventional tube and wing design? Does this affect its performance?

Blended wing bodies can produce more lift by its aerofoil configuration. It has been shown to produce up to a 30% decrease in fuel burn due to its additional lift, compared to a tube and wing plane. ...
2k views

### Are transponders sometimes referred to as ‘parrots’?

Looking at the A/FD for Anchorage Ted Stevens Intl (PANC), there are a couple of entries in in the airport remarks for a piece of onboard equipment called a ‘parrot’. I am not familiar with this ...
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1 vote
189 views

### Can smaller wing area improve the aircraft experience during turbulence?

Amid the recent incident of Singapore Airlines flight 321, leaving one dead after a severe turbulence, I ask myself if having an aircraft with smaller total area, there is less turbulent air that ...
• 3,733
1 vote
168 views

### Is there a relationship between thr increasing number of airliners flying over 11000 metres and the number of problematic air pocket events?

I saw many news about the death of a passenger on Singapore Airlines flight. They say that the accident was caused by a turbulence. But judging from the description of what happened I thought about an ...
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76 views

### Has the inceptor (control stick) ever been controlled via using CAN bus control?

The CAN bus is being used widely in the automotive industry, and some aircraft are using the CAN bus control. Is there any inceptor (control stick) or throttle that can be connected to the CAN?
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2k views

### How can I find the area situated under an airport traffic pattern?

For a given airport (general mix of traffic & runway setup/configuration), how can I determine/define which areas around the airport can expect to be situated under the traffic pattern for that ...
109 views

### Did the FAA used to require pilots to have valid sectional for VFR cross country flights?

Did there used to be an FAR in the 1990ies that required VFR pilots to have in their possession a valid sectional for cross country flights? I seem to remember this rule from before 2000, but can't ...
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### Can one tell if a craft is a lifting body or a flying wing just by looking at it?

Recent news that the "reusable lifting-body spaceplane" Dream Chaser has arrived at Kennedy Space Center and may launch in August launched led me to read Wikipedia's Lifting body which ...
• 6,028
99 views

### optimal loiter speed for an eVTOL air taxi

I'm not looking for a precise answer here, just a ballpark estimate of the optimal loiter speed for any model of eVTOL air taxi aircraft. In other words, if you just want to delay (kill time) in the ...
69 views

### Can a shock in certain circumstances be at a lesser angle than the Mach cone?

(Excuse the drawing quality) What will happen if a shockwave has an angle less than that of the Mach cone? In this picture, the black line represents the Mach cone. The orange line represents the ...
• 2,774
1 vote
214 views

### FAF: Lightning Bolt vs Maltese Cross on approach plates?

Here is my understanding (please correct me if I am wrong): A maltese cross is a FAF indicated with a distance and lightning bolt is FAF indicated by interception of glide slope. Non precision ...
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400 views

This video tells the story of a pilot who, according to government records: [Committed] four counts of identity theft related to his use of the victim pilot’s passport and personally identifying ...
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99 views

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### Does the flow turning amount change as you get further away from an object?

Will the flow turning amount change as you get further away from an object? This answer explains why shockwaves will extend past the body that made them (good starting point). This question is asking ...
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101 views

### What could have been done better in United Airlines Flight 232 when differential thrust was used?

In United Airlines Flight 232, on their DC-10, all hydraulic fluid and pressure was lost on all three systems, simultaneously. Fitch, who was a training check airman on the DC-10 was on board and ...
• 3,997
437 views

### Is it plausible that helicopters are safer than cars?

For some reason there is a lot of talk on helicopter safety online at the moment, and one fact that keeps coming up is "helicopters are safer than cars", supported by this article "Are ...
• 309
1k views

### Why the combustion chambers of a turbine engine aren't used to spin the compressor like a firework wheel?

I searched here in this stack and the only question I found was this one, but I feel like it wasn't very well worded and it is also considered a duplicate. If this question is considered a duplicate ...
• 620
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### Will the NTSB be involved in the investigation of the crash that killed the President of Iran?

On 19 May 2024, the President of Iran died following the crash of a Bell helicopter, originally built in America. My understanding is that following the crash of an aircraft, the international ...
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135 views

### How wide should taxiways be to serve a A350?

I'm planning a model airport and I really don't know how far the wing should be from the gate safety line (I think that's what it is called). The largest wingspan will be that of an A350.
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83 views

### Lift without aerofoil? [duplicate]

I have seen some RC planes flying without any form of airfoil, the wing is literally a flat board. What I want to understand is how lift is generated under these conditions. I understand kinetic ...
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1 vote
85 views

### Why does the angle of a shock change when the flow leaves the influence area of an object?

In this (great) answer, it says: "far enough" from the Concorde's nose, the path followed by the airflow is not affected by its presence and it's just a straight line. Close to the nose we ...
• 2,774
1 vote
18 views

### Input Parameters for Combustion Chamber

I am doing a column breakup study. But for a better study I need air velocity, turbulence intensity (not primarily needed though),temperature, pressure and same parameter for injected liquid fuel. I ...
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92 views

### Legal Requirement to reweigh aircraft?

For part 91 operations or regular trainer aircraft, what is the "LEGAL" requirement for which an aircraft re-weigh is required? The ONLY thing I can find on the internet is in the W/B ...
4k views

### Image recognition in air to air missiles

Given advancements in machine vision, what issues would there be if air to air missile guidance used image recognition (at least in the terminal phase) to defeat flares and chaff?
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### Is 200FPNM required up to the MSA or to the MOCA in the PLMTO3 SID

On the PLMTO3 SID out of KCHS, Rwy 15 has standard takeoff mins. From the AIM 5-2-9.e.1. Unless specified otherwise, required obstacle clearance for all departures, including diverse, is based on the ...
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### Do other countries aside from Israel have some special requirements on wearing seatbelt upon approaching destination but before the aircraft descent?

I read (mirror) that Israel has enhanced security procedures resulting in airplane passengers having to wear seatbelt up to 180 nautical miles before the destination: ISRAEL - TEL AVIV FIR — ...
121 views

### Whats the derivation of a low speed ratio for stall warning?

I've seen an equation related to stall and angle of attack in a few places like this patent that goes more or less: $$\frac{CAS_{alert}}{CAS_{current}} = \sqrt{\frac{C_{L,current}}{C_{L,alert}}}$$ ...
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74 views

### Can a B-707 recover from a spin? [duplicate]

There was an incident in 1959 involving a Boeing 707 on a training flight near Paris, France where a badly executed MCA demo reportedly resulted in the plane entering a spin, had an engine torn off ...
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173 views

### What does "ceo" stand for in Airbus A320ceo?

What does "ceo" stand for in Airbus A320ceo??
1 vote
81 views

I am trying to implement the ADS-L protocol in my application, but I did not fully understand it yet. Data link layer (page 13): Why CRC is at offset (Packet Length +1)Bytes if the CRC is included in ...
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185 views

### Why military parachute backpack stays with the aircraft?

As seen on this youtube video where military personnel jumps while the backpack stays attached to the aircraft, why is that? what is the purpose of it compared to the other non military skydiving ...
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2k views

### I'm having a hard time conceptualizing this statement from "The Jet Engine" by Rolls-Royce

This is taken from section 21 of Chapter 3, Compressors that discusses axial flow compressors in turbine jet engines. The more the pressure ratio of a compressor is increased the more difficult it ...
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108 views

### XFY-1 Pogo Contrarotating props alternative?

The Convair XFY-1 Pogo was a tail-sitter VTOL aircraft that used contrarotating props. I believe it was to counter the torque that would be produced if a single prop was used. Why couldn't the Pogo ...
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### Multiple annual inspections failed to find a problem that is now showing up - is there any recourse? [closed]

I purchased a 1977 Cessna 150M about 3 years ago. The aircraft is currently undergoing an annual inspection. The inspector has determined that the engine serial number does not match the engine ...
189 views

I understand wind direction can vary in a column of air? With only altitude control on a blimp to navigate for long flights, a blimp in theory could navigate without engines. In order to take real ...
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80 views

### Can we use leaf shutter mechanism as a drone dropping mechansim for payload weight of 3lbs?

I'm considering implementing a drone payload drop mechanism capable of handling payloads weighing up to 3lbs. I'm intrigued by the idea of using a leaf shutter mechanism for this purpose, but I haven'...
151 views

### In Jeppesen Approach charts, what does D2.8, D3.8 mean?

In Jeppesen Approach chart for VABB VOR RWY 32, what does D2.8 (BBB VOR), the MDA is lower at 650ft. when at D3.8 (BBB VOR), the MDA is higher at 780ft. How to decide which DME should be taken before ...
241 views

### Lightoff to speak about an engine start

Why is the term lightoff (or light-off) used to describe the moment an engine ignite/is started ? I'm wondering why the suffix 'off' is used in an 'ON' sense (start, ignition) ? Is there a ...
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### State of the art in aircraft industry for flutter analysis

I'm an aerospace engineering PhD student and for my research I'm investigating how to come up with a way to pick the most critical flight conditions for flutter. The main idea is to understand how it ...
5k views

### What's the minimum survivable mid-air collision altitude in a glider?

This weekend I had my first gliding experience in an ASK21. My first surprise was being given a parachute. The briefing was simple, if we have a mid air collision, unbuckle the belt harness, remove ...
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