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11 votes
2 answers
195 views

At what Mach number does a fan jet become more efficient than a turboprop?

Dynamic pressure is based on air density and the true airspeed of an aircraft. As one climbs, indicated airspeed can remain constant as true airspeed climbs, resulting in only minor changes in ...
0 votes
1 answer
42 views

Rotor-wing aircraft feasibility

Could an aircraft have a spinning wing as a helicopter rotor at low speeds which stops spinning at high speeds to act like an airplane wing? The tail-rotor would turn 90 degrees and become a pusher ...
0 votes
1 answer
59 views

Is dirigible cluster ballooning feasible?

Has steerable cluster ballooning with a propeller and fins/stabilizers of some sort ever been attempted? If not, would it really make sense at all, and what would the challenges be, as compared to a ...
0 votes
0 answers
28 views

What are the twin "air data booms" on the Su-22?

The Su-22 has two protruding "probes" at the nose. What are they? Air data probes (why two?)? Antennas? https://www.airliners.net/photo/Libya---Air/Sukhoi-Su-22M3/1615286/L
-4 votes
1 answer
92 views

Why didn't LO7898 fly near the North Pole?

I've seen LO7898's route from Seoul to Warsaw on flightradar24. Instead of flying the shortest route (over Mongolia, Russia and near the North Pole) it flew as if Earth was a cylinder: over China, ...
1 vote
1 answer
54 views

How tall is the 747-300 without the tail height?

I know that the 747-300 tail height is 63'5", but how tall is the fuselage alone? Also, what is the height of the cargo area and main cabin?
1 vote
3 answers
4k views

When is 'heavy' used in callsign?

I have heared at ATC communication that some aircraft uses a heavy word in the call sign. What does heavy means? When it is used? Is it used when aircraft is heavier than 200-300 tons?
7 votes
5 answers
10k views

How long is a winds and temperatures aloft forecast valid for?

How long is a winds and temperatures aloft forecast valid for and how often is it published? Also, is there anywhere which says the times of publication and valid through times for all of the ...
-1 votes
1 answer
68 views

Airbus' official language

I want to know which language Airbus uses when they create the original version of their official documents. Airbus is not U.S Company, so I think they just don't use English when they create the ...
0 votes
0 answers
8 views

Difference between the ATA Spec 2000 and the ATA Spec 2200

Could someone explain the difference between the ATA Spec 2000 and the ATA Spec 2200 (iSpec 2200) standards for data exchange? Thanks.
0 votes
1 answer
79 views

Can state police legally order a GA aircraft to immediately land?

In 1998, the Senate was considering adding language to the Coast Guard appropriations bill that would authorize State Police to issue orders that a GA aircraft must immediately land. In that instance, ...
5 votes
1 answer
159 views

Can anyone identify this biplane in 1940s Orange, MA?

The picture was taken at Orange Municipal Airport in Orange, MA, in the 1940's. I can't identify the logo either.
6 votes
3 answers
3k views

Why do tailplanes provide down force, if not for longitudinal static stability?

We can see that most conventional aircraft have their horizontal tail surfaces arranged to provide a down force. This question asks if that is required for static longitudinal stability, and the ...
1 vote
1 answer
109 views

Aircraft with air bags for seats

Are there any (passenger) aircraft models with airbags for seats? I had never heard of it but was watching a film where a Virgin Atlantic engineer mentions it for their business class and premium ...
0 votes
3 answers
98 views

Turbofan ‐ turboprop/shaft hybrid?

If a turbofan engine can create more thrust than a standard turbojet engine, would a turboshaft engine benefit from using a turbofan to power the shaft, in a hybrid kind of set up?
1 vote
0 answers
43 views

Why have supercritical airfoils not been used in designing the propeller blades?

In terms of specific fuel consumption, propellers are more economic than jet engines at low speeds (<0.5 Mach) but at high speeds, the propeller blade tip reaches locally to supersonic speeds which ...
0 votes
1 answer
164 views

What is this aircraft seen near Farnborough almost every day?

Can anyone identify the aircraft seen almost every day making for Farnborough airfield based on this description? medium sized aircraft single front engine with a weird engine sound front fins, could ...
0 votes
1 answer
64 views

If a plane doesn't require 100 hr inspection, but an AD must be checked every 100 hours, does that require a full 100 hr inspection?

Let's say a person privately own a plane and they are not using it for hire or instruction. So they are not doing the 100 hour inspections. However, there are several ADs that require it to be checked ...
0 votes
0 answers
53 views

747 Fuel Drain Ports

I read about the fuel systems on aircraft for a project I'm working on, and I was wondering about the "fuel drain ports" mentioned, which the document stated were used for complete drainage ...
-1 votes
0 answers
51 views

Difference between head and tube

What is the difference between static head and static tube? Similarly, what is the difference between pitot tube and pitot head?
1 vote
1 answer
103 views

Logging Dual Received in a Single-Pilot Turbojet, FAA

Can you log dual received in a single-pilot turbojet on Part 91 flights if the PIC is type-rated, holds a valid MEI and instruction is being given? Can the AMEL-rated student log AMEL category and ...
4 votes
1 answer
119 views

Is the ISA still up to date?

The Standard Atmosphere dates back to 1962 when Earth was colder. The 1976 update didn't make changes within 50 km altitude (the tropo- and stratosphere). It assumes 15°C at sea level, decreases until ...
1 vote
1 answer
34 views

Can I log a VFR XC toward 141 commercial license while simulating instrument

I flew last night with a friend to split time. Half the flight I wore foggles, half the flight he did So we could both be PIC And both have approach/landing practice. Could I log all of that ...
3 votes
1 answer
58 views

Can a 121 designated SIC log Pilot In Command time under 61.51 (e)?

This may seem like an easy answer at first: no. The generally accepted rule within part 121 is that a designated SIC never logs PIC time, whether they are a FO, Captain, or Check Airman. That's the ...
8 votes
2 answers
2k views

Could ducted propellers improve efficiency in small drones?

I have seen that a new electric airplane design has decided to choose ducted propeller with a design somewhat similar to the one of jet engines, explaining this design choice with the fact the ducted ...
3 votes
0 answers
58 views

What is the aerodynamic impact of the curved/crescenteric wing of the Boeing 787?

From certain angles (see pictures below), the wing of the Boeing 787 seems almost curved/crescenteric in shape, particularly closer to the wing-tip. While the Boeing 787 makes use of "raked ...
9 votes
1 answer
427 views

What equations and constants did they use to build the E6B flight computer?

E6B Flight computer: During my practice test, I tried to use the wikipedia provided equations to calculate Density Altitude and ended up with different results than the E6B. In this case, it looks ...
2 votes
1 answer
55 views

Can you choose to swap to a PPL when learning a (EASA) LAPL?

If I were to start flight training for a (EASA) LAPL and decide later (before completing the LAPL) that I wanted to do a PPL instead, is a switch possible? Could the hours flown in pursuit of the LAPL ...
0 votes
0 answers
48 views

How to determine date of pilot license?

I wonder if someone can tell me how to find out what year my Dad got his private pilot license as well as his commercial pilot license? BC Canada Thank you.
5 votes
1 answer
163 views

How is airline fuel hedging actually done?

When airlines refuel at the airport are they all billed at the same rate on the day? Similar to cars at a gas station? For example if Southwest has hedged and paying a dollar less per gallon than its ...
0 votes
0 answers
34 views

How to choose an attack angle?

I'm writing a little piece of code for preliminary design that can calculate the ideal wing area for a given load, cruise speed and aspect ratio or span. It seemingly works well on the A380 data: <...
16 votes
5 answers
6k views

The FAA is asking for medical records that I don’t want to give. May I refuse?

My first class medical was deferred because I had optic neuritis due to a side effect from the covid vaccine. I was treated and my vision went back to 20/20. Now the faa is asking for a vision test ...
9 votes
2 answers
1k views

The F/A-18 Hornet and MiG-29 ailerons from the external parts of the wings go up some degrees in flight. Why?

In some parts of the flying envelope of the F/A-18 Hornet and MiG-29 the ailerons from the external parts of the wings go up in sync. They're made to go one up one down in order to get rolls, not up/...
10 votes
1 answer
2k views

How are weather balloons different from "regular" big latex balloons?

If I search the internet for "weather balloon" I get much higher prices than if I just look for "big balloon". Just to compare these two listings in particular: this \$320 weather ...
-1 votes
0 answers
45 views

What is this instrument in front of the vertical stabilizer in an airbus 321? [duplicate]

https://www.jetphotos.com/photo/10491879 There seems to be a small, flat-ish structure in front of the vertical stabilizer. What is it?
6 votes
3 answers
3k views

ID this plane with a white body and a blue stripe

Going through my Dad's things I found this plane and would love to know what it is.
3 votes
2 answers
273 views

Do new VHF radios need to be flight tested?

I'm in the process of upgrading all our VHF radios and the local regulator has asked us to follow the guidance/recommendations from ICAO, as we have more or less cancelled many of our local rules. The ...
1 vote
2 answers
76 views

Does tip dihedral have lesser increase in lift over a full dihedral wing?

I have read some articles mentioning that a full dihedral reduces the lift produced by a wing. So what about a tip (or cranked) dihedral that has the angled part starting from the mid-wing rather than ...
6 votes
1 answer
1k views

The fuel shut-off valve was left in over night. Is it dangerous for the plane?

I forgot to pull the shut-off valve in my plane (PZL-110 Koliber 150) while I was trying to start an engine. Will this have any effect on the plane? It has a mixture supply knob and is a pull/push ...
0 votes
1 answer
114 views

Which speed should we look for recommended brake cooling in case of rejected takeoff?

Which speed should we look for recommended brake cooling in case of rejected takeoff? (Airspeed or groundspeed)
0 votes
0 answers
47 views

How did the X-15 measure altitude above 86 km? [duplicate]

The 1962 standard atmosphere ended at 86 km (282,000 ft MSL), didn't it? How high was the X-15's altimeter able to work and how did it measure the altitude when going higher than the Standard ...
0 votes
2 answers
284 views

How do Luneberg lenses hide a stealth aircraft's real signature?

I thought aircraft was supposed to be stealth and not show up on radar under the right conditions. This article says Removable Luneburg lens type radar reflectors are sometimes attached to military ...
1 vote
2 answers
119 views

Why can canard wings not be used in all sonic aircraft despite their high control?

As Canard serves two purposes; it improves aircraft control, also contributes to lift, replacing the horizontal stabilizer and - theoretically - reducing overall drag.
1 vote
1 answer
209 views

Can I get an ATPL if I have two drinking-and-driving offenses in the UK?

Can I get an ATPL if I have two drinking-and-driving offenses in the UK? I am thinking of becoming a pilot and a would like to know if there is a possibility (of course, after a period of time, and of ...
-5 votes
3 answers
199 views

PC-24 has a cargo capacity of only 400 pounds?

I went to book a PC-24 with 3 passengers weighing a total of 450 pounds and 700 pounds of luggage for a total of 1,150 pounds. I thought this was doable because the payload capacity of a PC-24 is ...
3 votes
1 answer
328 views

Departing from closed traffic

I understand how to request closed traffic from the ground, and what it allows me to do (What does "closed traffic" mean?). There's another closed traffic scenario that I imagine to be ...
1 vote
0 answers
28 views

Along Track Distance ATD

ATD (Along-Track Distance) is used by ATC for certain types of (rare) NON-Radar Separation. I am training as an Air Traffic Controller in the USA. I have been told the only way to know if an aircraft ...
0 votes
1 answer
211 views

What are the applications, advantages and limitations of Gyrodyne rotorcraft?

Gyrodyne is a VTOL rotorcraft. It has ability to power both rotors and propellers for generating lift and thrust. What makes it of lesser popularity than helicopters. Are there any applications of ...
36 votes
2 answers
7k views

What are these boxes built into the tails of some fighters?

In looking at European-designed fighters of the 4th and 4.5th generation, I keep seeing a common design feature; a box-like structure built into the tail, often in the top half or third. Some examples:...
7 votes
1 answer
260 views

Making a plane fit to fly after accidental emergency exit / slide deployment

Every so often there is a report of a person openening an ( armed ) emergency exit unauthorised on the ground leading to a slide deployment. Often this is followed by the flight leaving after ...

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