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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 ...
Wyatt's user avatar
  • 2,405
0 votes
0 answers
9 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 ...
J. Brown's user avatar
1 vote
1 answer
20 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 ...
CoffeePilot's user avatar
2 votes
2 answers
261 views

Image recognition in air to air missiles

Apologies if this is the wrong group. 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 ...
Peter's user avatar
  • 233
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0 answers
49 views

Need help identifying an airfield

I'm guessing Russian or Ukraine. It is VERY similar to Soltsy, but that is not it.
gareit's user avatar
  • 1
0 votes
2 answers
23 views

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 ...
Name's user avatar
  • 916
0 votes
0 answers
57 views

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 — ...
Franck Dernoncourt's user avatar
1 vote
2 answers
53 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: $$ \frac{CAS_{alert}}{CAS_{current}} = \sqrt{\frac{C_{L,current}}{C_{L,alert}}} $$ ...
RealAnswersNotAI's user avatar
2 votes
0 answers
69 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 ...
Roy Smith's user avatar
  • 121
0 votes
1 answer
100 views

What does "ceo" stand for in Airbus A320ceo?

What does "ceo" stand for in Airbus A320ceo??
Sambhav Khandelwal's user avatar
0 votes
0 answers
36 views

What happened to the SkyTote UAV?

The SkyTote UAV is a tail sitter VTOL UAV, which looks like the Convair XFY-1 Pogo (without the delta wing). I want to know whether this design ever transitioned successfully from hover to cruise mode....
NeelD's user avatar
  • 21
1 vote
0 answers
50 views

ADS-L Protocol implementation

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 ...
Murmi's user avatar
  • 11
0 votes
1 answer
141 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 ...
Gabe's user avatar
  • 3,217
0 votes
0 answers
34 views

Difference between MEL, DIL and HIL?

Can someone explain what is the exact difference between the minimum equipment list (MEL), deferred item list (DIL), and hold item list (HIL)?
Darjan's user avatar
  • 1,157
4 votes
2 answers
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 ...
shrimp's user avatar
  • 41
0 votes
1 answer
97 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 ...
NeelD's user avatar
  • 21
2 votes
0 answers
128 views

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 ...
Gary Moore's user avatar
3 votes
2 answers
147 views

Engineless Blimp Navigation System

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 ...
Justintimeforfun's user avatar
0 votes
1 answer
73 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'...
Ujjwal's user avatar
  • 9
-1 votes
1 answer
104 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 ...
Krishna Kanth's user avatar
2 votes
2 answers
197 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 ...
Vincent's user avatar
  • 21
2 votes
2 answers
111 views

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 ...
user9870949's user avatar
-1 votes
0 answers
87 views

Do tip vortices actually make drag or are they the result of drag?

Do tip vortices actually make drag? I know that they (probably) reduce the L/D ratio by reducing the pressure differential between the top and bottom (which would effectively make the wingtip not ...
Wyatt's user avatar
  • 2,405
10 votes
1 answer
4k 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 ...
Cloud's user avatar
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0 votes
1 answer
74 views

What is the main reason raked wingtips are more efficient than winglets? [duplicate]

What is the main reason that these: Are more efficient than these?: My main guess is that they improve L/D compared to winglets, as they provide more upwards lift making them more efficient. It ...
Wyatt's user avatar
  • 2,405
3 votes
1 answer
81 views

Angle of bank affects on descent rate

I’m attempting to do some maths regarding the ‘impossible turn’ (engine failure after takeoff, followed by a 180+ deg turn back to the field to land). I understand how to determine radius, rate of ...
Ryan BW's user avatar
  • 31
10 votes
1 answer
219 views

Were there height requirements for SR-71 pilots?

I recently sat in the SR-71 cockpit at the Museum of Flight in Seattle. I am 6'5" tall and it seemed I was too tall (with the existing seat configuration). Another post on this forum noted that ...
Michael Watkins's user avatar
0 votes
4 answers
284 views

Why cant all planes use the best engines like the GeNX or the Trent XWB?

Why do airline manufacturers not prefer using the best engines(max thrust: weight ratio and best efficiency) for their airplanes? Doesn't this just not lead to lower sales and losses for the company? ...
Sambhav Khandelwal's user avatar
5 votes
4 answers
1k views

How can the wing generate more lift than the thrust? [duplicate]

I recently checked about the max takeoff weight of an A380 and the thrust it can provide at TO/GA power and I was quite shocked by the results. The total thrust by the engines was only about 127000 ...
Sambhav Khandelwal's user avatar
15 votes
3 answers
6k views

Can a piece of duct tape bring down a plane today (Flight 603, 1996, Perú)?

According to Wikipedia, the reason for the crash was that: adhesive tape had been accidentally left over some or all of the static ports (on the underside of the fuselage) after the aircraft was ...
Gabriel's user avatar
  • 261
1 vote
0 answers
65 views

Will we ever see unconventional airplane configurations in operation? Will they completely replace the normal tube and wing design? [closed]

I have recently been looking into novel airplane configurations such as the blended wing body, transonic truss-braced wing, and box wing proposed by many aerospace companies like Boeing and NASA (...
E. Chao's user avatar
  • 11
-2 votes
1 answer
146 views

What are these strakes on the belly of the F-16 for?

What are these 2 things doing under the F-16? Are they for aerodynamics? Source.
f FRENZY's user avatar
0 votes
0 answers
48 views

Does the FAA allow changing an aircraft's registered class?

For instance, if an aircraft is first registered as an airplane, can it later be changed to a glider or vice versa? How about a single converted to a multi? (If you're wondering about why this could ...
Kenn Sebesta's user avatar
  • 5,142
0 votes
3 answers
254 views

Why does the shock angle always seem to equal the "sound cone" angle?

(I'm going to use the term "sound cone" for the area you can hear an aircraft when it's at Mach ≥ 1, illustrated by this picture. Not considering the shockwave.) So as explained in this ...
Wyatt's user avatar
  • 2,405
1 vote
1 answer
179 views

What is the squawk for VFR flying?

I'm used to using squawk 7000 for VFR flight. But lately I've seen 1200 also being used. I don't know which one is the default for VFR flying, because it seems like both codes are widely used.
OnyxWingman's user avatar
0 votes
1 answer
134 views

Can a sound wave travel through a shockwave?

Say you have a scenario where there is a shockwave, and you sent a normal sound wave towards it. Could the sound wave travel through that shockwave? If so/not, why? Would it depend on the strength of ...
Wyatt's user avatar
  • 2,405
0 votes
0 answers
39 views

induced drag at supersonic speed [duplicate]

for a delta wing with supersonic leading edge at small angle of attack there is no stagnation point on leading edge so There is no connection between the top and bottom of the wing. Therefore, the air ...
alireza's user avatar
  • 113
1 vote
2 answers
107 views

Why does adding heat to the subsonic flow increase the speed of the flow?

In Rayleigh flow, adding heat to the subsonic flow increases the speed and adding heat to the supersonic flow decreases the speed. But what is its physical cause?
alireza's user avatar
  • 113
2 votes
1 answer
53 views

Question about MOCA and MEA

Why is there sometimes a MOCA on the chart and sometimes only an MEA? In the picture, there's only an MEA until BAGBY, and then MOCA appears after BAGBY. Do you know why this is happening?
user75593's user avatar
1 vote
1 answer
96 views

What is the unit of the DAP MCP/FCU Selected Altitude as transmitted by the transponder?

The ICAO document Mode S Downlink Aircraft Parameters Implementation and Operations Guidance Document mentions the DAP Selected Altitude. Is the unit of this DAP always in flight level (i.e. without ...
Markus's user avatar
  • 113
1 vote
1 answer
233 views

On the 737 when you experience an engine failure just after take off. And you do not have any visual reference? Which instrument should we see? [closed]

On the 737 when you experience an engine failure just after take off. And you do not have any visual reference? Which instrument or which parameter should we see to correct our direction change? And ...
Deepak's user avatar
  • 403
19 votes
5 answers
6k views

Has there ever been a transfer of occupants from one aircraft to another while airborne?

Similar to the mechanism used in aircraft tankers (picture below), has there ever been a transfer of occupants from one aircraft to another using some sort of "air bridge"? Crazy idea: How ...
Gabe's user avatar
  • 3,217
0 votes
1 answer
59 views

Question about V25 route's MOCA

I found something curious about the V25 route on the en-route low altitude chart. Before LAPED, there was no MOCA indicated, only an MEA of 9000. Why does MOCA 6500 appear after LAPED?
user75593's user avatar
4 votes
1 answer
793 views

Why Cessna 152 has different airfoils at the root versus at the tip of the wing?

I recently read that C152 have two different airfoils on its wing. NACA 2412 at the wing root and NACA 0012 the wingtip. Why? And why are those particular airfoils (with their inherent aerodynamic ...
Konrad's user avatar
  • 2,025
1 vote
1 answer
230 views

Lift Coefficient question

I am making a RC Airplane, it has a wing profile as shown above. What might be the approx. lift coefficient of this? The wingspan is 80cm, what will the lift provided be by this wing at 65kmph ?
S.A's user avatar
  • 43
2 votes
1 answer
207 views

WWII fuel gauge: single needle and dual range

In T-34 movie there is a scene where a WWII small aircraft is flying: and the pilot warnings the official that they're running out of fuel and a quick close up of the cockpit shows the fuel gauge: ...
Mark's user avatar
  • 293
1 vote
0 answers
87 views

RC Airplane Questions [migrated]

I'm making a RC Airplane using Sunboard and Cardboard. The wing is about 80cm long, with a wing profile looking like I also connected a A2212 1000kv Brushless motor with a 10x4.5 Inch Propeller. To ...
S.A's user avatar
  • 43
1 vote
2 answers
214 views

AirBus A380 and Boeing 747 - fuel consumption while taking off?

I have talked with my friends about fuel consumption while taking off. None of us know much about airplanes, so I'm asking here, because I didn't find an answer searching on the internet. How much ...
JanezKranjski's user avatar
1 vote
2 answers
113 views

Does separation happen easier with less dense air?

Does less dense air affect when separation happens? So if you have a cylinder traveling in a straight path like the one above, there is separation happening at a given speed. If you were to change ...
Wyatt's user avatar
  • 2,405
14 votes
2 answers
5k views

Can the "Flying Whales" cargo airship really hover to be able to lift freight on board?

The figure below shows a cargo airship called "Flying Whales LCA60T" able to carry 60 tons of freight. In order to take the useful load from one location, the dirigible has to discharge up ...
Robert Werner's user avatar

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