# All Questions

25,806 questions
Filter by
Sorted by
Tagged with
37 views

### Is the yaw damper on modern airliners safety critical? [duplicate]

Question is inspired by the recent Southwest 737 MAX Dutch Roll incident. The news articles said the crew "regained control", which implies that the aircraft was out of control prior. I did ...
341 views

### How to calculate velocity of air behind a propeller?

Background: I came across this article by Gabriel Staples to calculate static and dynamic thrust of a propeller. In the derivation, it was assumed that the exit velocity is equal to the pitch speed of ...
• 79
61 views

### Why will the max lift point not be at the center of a swept but constant chord wing?

(In this question when I say "swept wing" it means the blue wing seen at the bottom. So no fuselage or anything) If you look at this graph from this answer, you'll see the max lift point of ...
• 2,666
1 vote
46 views

### Understanding the constant speed prop and 2-4 degrees optimum

I've read through some answers on here and just wanted to write my own description of how this works and let someone check for me. Currently I've just started to fly an King air 100 with PT6A We ...
64 views

### Why do some GA aircraft use bungees or torque tubes vs. cables for control surface actuation?

Why do some GA aircraft use bungees or torque tubes vs cables for control surface actuation? I understand using cables is the most common for GA aircraft. I understand bungees are common in gliders ...
• 1,313
1 vote
51 views

### What happens in order to make a shock when the flow first turns?

Imagine you have a really zoomed in view of a 2d ramp, which is at 20 degrees. Zoom in on the exact point the ramp turns from horizontal to 20 degrees. When the first supersonic air molecules reach ...
• 2,666
60 views

### Do you have to repeat back ATC taxi instructions while still on the runway [duplicate]

Upon touching down while still rolling, tower gives us taxi instructions back to parking. I understand the need to give instructions on where to exit the runway but I’m wondering if the FULL taxi ...
88 views

I'm balancing a three-blade propeller. The propellers weigh exactly the same to the 10th of a gram. When I place it on shaft with a very sensitive wheel bearing, one of the blades always moved ...
108 views

### Why will the pressure distribution of a swept wing promote stall?

Here it explains how the bound vortex will change the lift distribution of a wing. What is meant by the lift distribution changing is that there is less lift at the tip, meaning the pressure ...
• 2,666
1 vote
56 views

### McCauley propeller models IC235/LFA7570 and IA170E/JHA7660

I am writing to inquire about the pitch specifications for the following McCauley propeller models: IC235/LFA7570 with a maximum diameter of 75 inches and minimum diameter of 74 inches. IA170E/...
89 views

### Holding time during static structural testing of a composite wing

While doing a static structural testing of a composite wing (high aspect ratio or otherwise), is there an industry practice or standard that determines the holding time for which a load is applied ...
3k views

### What type of aircraft is this?

Flew very low in circles around my house this morning. I live near Fox Harbour airport in Wallace, Nova Scotia Click to embiggen
• 133
66 views

### EASA Regulations regarding Private Aircraft for PPL training

Can somebody advise what are the EASA specific regulations that apply regarding the use of a privately registered aircraft for PPL training? Links in particular to the EASA website would be greatly ...
• 21
1 vote
51 views

### SERA.8012 and ATS.TR.220 Wake Turbulence Separation application

I need small clarification on current European documents SERA and Part-ATS. Based on SERA.8012(a): (a) Air traffic control units shall apply wake turbulence separation minima to aircraft in the ...
1 vote
120 views

### How does the downwash behind a swept wing differ from a normal wing?

How does the downwash behind a swept wing differ from a normal wing? (I know you can’t trust everything you see on the internet, but this seemed legitimate) Here it said: The downwash pattern on a ...
• 2,666
248 views

### What is the purpose of these round paved pads?

What is the function of these round pads at KMWH, Grant County International Airport, in Moses Lake, WA? They appear to be sized to allow an aircraft to turn around, perhaps under its own power or for ...
• 303
1 vote
62 views

### Where do I find the requirement for an AFM to be serial number specific?

It seems to be generally accepted that an AFM must be serial number specific to that aircraft it was made for and delivered with. I am having difficulty finding the reference for "serial number ...
1 vote
141 views

### Need help Identifying Aircraft Panels

I have the following aircraft panels which I would like to Identify and get an understanding of its value. Any help is greatly appreciated! First Panel: Length: 19 ½ in. Height: 8 in. Second Panel: ...
• 11
2k views

### Structure that holds the twin-engine on an aircraft

What is the name of that big structure (in red) that holds the engine?
7k views

### Can someone explain the damage distribution on this aircraft that flew through a hailstorm?

An A320 flew into a hailstorm 20mins from landing. I’m intrigued by the damage distribution. Seems like everywhere else wasn't touched at all. Why?
• 241
54 views

### Relation between Saab B3LA concept aircraft and AMX International

The Saab B3LA aircraft concept and the AMX aircraft were developed around the same time and out of similar requirements. According to the Swedish Wikipedia: The [B3LA] project was abandoned in 1979 ...
• 121
1k views

### Airplane Owner, But don't have PPL. Can student pilot do oil change on their own plane?

Airplane Owner, But don't have PPL. Can student pilot do oil change on their own plane? I can't seem to find answer on this. Any helps would be great.
6k views

### Am I seeing double? What kind of helicopter is this, and how many blades does it actually have?

This June 9, 2024 CNN news video begins with an inset of video of what looks like an Israeli IDF "event". Looking down from a relatively static point in the air, another helicopter is seen ...
• 6,028
1 vote
360 views

### Why hasn't there been an alternative to jet engines yet?

Why do airlines and military jet aircraft still use jet engines after 85 years of the introduction of this technology? Why hasn't there been a viable alternative to jet engines yet, even though this ...
• 884
77 views

### Any one met this trouble on E4-C engine? [closed]

I cannot read the flight data on AE300-Wizard, and it shows "File contains no valid record manager sectors or is corrupt." I plan to re-import the E4-C update file. Any solid advise on this ...
1 vote
22 views

### Is QNET 2.0 VTOL Board Underactuated or Fully Actuated?

I'm working on a VTOL aircraft model, but the apparatus available in our lab is the QNET 2.0 VTOL Board. The help I need is to confirm whether the VTOL Board is underactuated or fully actuated. As you ...
• 11
43 views

### What are the maximum dimensions and weight per piece that can be loaded on a 737-800BCF (Boeng Converted Freighter)

The 737-800 Boeing Converted Freighter aircraft cargo specs are widely available on the Boeing and other related websites, but the actual per piece maximum dimensions and weight than can be fitted on ...
60 views

### How to calculcute variation and compass deviation in this CDMVT problem?

Usually I can solve CDMVT problems, but sometimes I feel I'm missing something important. For example: I'm able to solve: Given WCA -012, TH 125, MC 139, DEV 002E. What are TC, MH and CH? ...
96 views

### Why are shockwaves allowed different angles at different distances from a body?

It's been (well) established that a shockwave can only be at the angle of the Mach cone. (I now understand this part). However, in this picture: you can see that the shock is at 2 angles. I also ...
• 2,666
35 views

### Are the spring constant and damping coefficient of landing gear publicly available?

I'm trying to find the spring constant and damping coefficient for a Cessna 172. I looked through the POH, but couldn't find them anywhere. Are these values available publicly in some design document ...
• 245
234 views

### Dyke Delta dynamics?

I recently came across the Dyke Delta, designed by John Dyke. It is a delta wing (more like diamond planform) homebuilt. I'm curious about how this airplane handles, considering delta wings have some ...
64 views

### What is the reason that Iranian Shahed-type drones have become so popular with Russian forces? [closed]

What is the reason that Iranian Shahed-type drones have become so popular with Russian forces? What is special about Shahed, which is a very low-tech drone that allegedly uses noisy moped engines?
• 884
56 views

### Why will a slower moving parcel of air above a wing create drag in non-inviscid flow?

This answer explains why a thicker boundary layer will cause a type of form drag. It uses inviscid flow to explain this. It is a great answer, but I can't seem to see how this applies in a real world ...
• 2,666
147 views

### What percentage of airliners today operate with unaugmented GPS equipment?

Responding to this question there was some discussion on GPS equipment and whether it used augmentation (WAAS/SBAS/GBAS) or not. What percentage of airliners operate with unaugmented GPS equipment? ...
• 20.7k
85 views

### ILS Designated Operational Coverage (DOC)

During a standard Instrument Landing System (ILS) approach, I typically arm the VOR/LOC (Boeing 737) to capture the localiser1 once on an intercept course. Upon clearance for the approach, I then arm ...
• 2,571
1 vote
239 views

### How do the landing gears support so much mass?

The first thing that one notices after seeing an aircraft, is that it's quite a heavy flying machine. And so, one would expect monumental tires on these vehicles, but yet they don't exist? How is it ...
1 vote
160 views

### How are military aviators call signs made?

Military aviators always have a call sign that they are referred to as. I would like to know how they are picked? Is it their personality, surname or what?
5k views

### Why do airplanes sometimes turn more than 180 degrees after takeoff?

Why do sometimes (at least in commercial flights) airplanes do a more-than-180-degrees loop after takeoff, in order to aim at the target direction? See image for an example. I guess that it is part of ...
152 views

### Is there any version of CFM56 with can combustors?

This lamp is sold online: They claim it's made from a CFM56 combustion chamber. It looks like a can combustor, and I read everywhere that CFM56 uses an annular combustor. Is there a version of CFM56 ...
• 203
345 views

### Which underwater crash sites of medium to large aircraft have been captured in sonar imagery?

For which crash sites of medium to large aircraft are sonar images available ? Scope: The crash site should already be confirmed (not speculated). For the purpose of this question, let's define "...
• 3,474
1 vote
76 views

### Twin engine or single engine with parachute, which is safer?

Statistically speaking, if we compare two airplanes: a twin engine (like the Beechcraft Baron) VS a single engine with a parachute (like the Cirrus SR22), if we add up all posible emergency events(...
• 3,327
76 views

### Flying N-registered Aircraft in the EU (as an EU resident)

Until recently, I believed what the old, wise men of my local flying club had been telling me for years: You can fly N-registered aircraft in Europe... as long as you have an FAA license. I recently ...
• 1,694
61 views

### How does a thickening boundary layer create form drag?

Imagine a normal wing with flow over it, and to simplify things it's at 0 AoA. Drag is being made mainly because of form drag and skin friction drag. I'm not sure on this, but I don't think there ...
• 2,666
159 views

### A question on stalling and flat spin - in gliders

Very short version: Do gliders do stalls, and flat spins, as aerobatic tricks (as do say aerobatic biplanes). -- As I understand it, with an aerobatic plane, a pilot can and does, for "fun" ...
• 1,932
147 views

### What's the precision difference between ILS and GPS(LNAV/VNAV)?

What is the precision/accuracy difference between both GPS (LNAV/VNAV) and ILS?
• 3,327
3k views

### Vintage photo, Seatac airport

I’m spending the night in a hotel at Seatac Airport in Seattle, Washington, USA. The vintage photo below is hanging on the wall of my room. I recognize the airport as Seatac, circa 1950’s. The photo ...
• 521
151 views

### How did the Concorde’s glide ratio vary from takeoff to supercruise?

I can't seem to get straight numbers on its glide ratio. One source claims 4:1 at takeoff and 12:1 at transonic speeds. But what about the supercruising phase that it's flight was optimized for?
2k views

### How do planes deal with excess lift at high speeds?

If I understand correctly, wind force increases quadratically as airspeed increases. Therefore, all other things being equal, lift should also increase quadratically. Does that mean, a plane going ...
181 views

### What limits automated direction finding from working over oceans?

Automated direction finders are only reliable in relative close proximity to NDBs, due to various adverse effects. In particular, the night effect limits their useful range for navigation ...
• 261