Re: Question on aircraft tires

IIRC there is a patent to add little scoops on the tires to spin them up from the airflow. The issue is you would also spin them when you take-off, too. You'd therefore have to brake them more on retraction and I guess brake wear is more costly than tire wear. You'd also be adding weight to the gea...

Re: Question on aircraft tires

What about landing on a conveyor belt?

Re: Why no single-engine GA aircraft with contrarotating propellers?

The existence of the technology and lack of adoption for the use case implies that everyone who's investigated it so far concluded that the juice wasn't worth the squeeze. If you were to do an A-team B-team comparison on some light GA single, you'd probably get the following outcome: A: single-stage...

Re: Boom Supersonic new configuration.

The comparison to Rekkof is so true. Permanent vaporware with just concept images. Aren't they behind schedule on the demonstrator? They claim four engines will actually decrease costs. "Additionally, the four-engine design reduces noise while also decreasing costs for airline operators."...

Re: Aircraft headings, bearings, and such.

GalaxyFlyer wrote:

Auto correct, yes latitudes, not altitudes.

Re: Aircraft headings, bearings, and such.

Thanks for the answers. I assume that when you say you would turn the short direction, it means you, the pilot turn the yoke. If you are on autopilot, flying due north and are told to turn to 270, you dial this in, does the flight computers also turn the short direction? Can you direct it to do oth...

Re: Aircraft headings, bearings, and such.

I often hear "turn 10 left" in my area when we fly from one approach sector to the next. There are a few departures where they want us to turn the long way from, say, a 130 heading to 250, so we usually get a repetition, "Left turn, left turn heading 250." I recently had a "...

Re: Widebody vs Narrowbody Cruise Speeds

I think that faster NB speeds will only happen if they're optimized primarily for the longer sectors, which I don't see happening. The vast majority of 737s and A321s do 1-3 hour flights, and then pinch-hit on 5-hour flights a small fraction of the time. The engines and layout are optimized for tho...

Re: Widebody vs Narrowbody Cruise Speeds

With NB now regularly flying 5hr + sectors, it will be interesting to see if the next generation of NB will indeed fly similar speeds to WB. Well, they are faster than before. The 737 used to cruise at .74. Now they cruise more like .80. I think that faster NB speeds will only happen if they're opt...

Re: A321XLR vs first generation long haul jets

The Airbus is much more efficient even comparing a 757-200 to a 707-320B the Maximum Takeoff Weights was about 240,000 pounds for the 757 & the 707 with their 4 Pratt and Whitney engines was about 320,000 pounds. The 707 could fly about 11 hours which would do LAX to LHR and Tokyo nonstop. The ...

Re: A321XLR vs first generation long haul jets

The Airbus is much more efficient even comparing a 757-200 to a 707-320B the Maximum Takeoff Weights was about 240,000 pounds for the 757 & the 707 with their 4 Pratt and Whitney engines was about 320,000 pounds. The 707 could fly about 11 hours which would do LAX to LHR and Tokyo nonstop. The ...

Re: Widebody vs Narrowbody Cruise Speeds

It's an optimization problem. Today's narrowbodies don't usually go as far, so speed is less important. Related to this, they usually have less sweep, around 25 degrees, versus 30-33 for most modern widebodies. That saves structural weight. Since the 737's 25-degree wings, the A320 and 737NG were ab...

Re: Test-pilot combine aircracft designer

Yeah, plenty of professional aero engineers build their own kitplanes and test them. If you're asking how many people at e.g. Airbus or Boeing do systems layouts and then also go and test the planes, I'm not sure.

Re: CFM Engine High Oil Consumption

We once had a European outstation “service” the oils on a CF6. They wrote 0 pints of oil uplifted in the logbook. It became obvious that they did not service oils to full once the plane got back to base. I'm a bit befuddled. Wouldn't the logbook entry of 0 pints make it obvious, or am I missing a t...

Re: Augmented crew - logging flight hours

There were guys that would bid RFO to make it easy then complain to the capt they were coming up on their 3 & 3. Then there was the issue of "hey man you knew this so why did you bid RFO? Ugly. What is a "3 & 3"? Pre-command upgrade review? People who complain like that seem ...

Re: Throttle levers on 4+ engined aircraft

How many of today's engines actually regulate thrust linearly though? I know several engines use N1 as their primary parameter, and thrust scales as roughly N1^2. Do those systems linearly set N1 (so x amount of deflection gives you y amount of delta-N1)? I'd think that an old-school system with a ...

Re: Throttle levers on 4+ engined aircraft

Anyway back to my original question: Why "thrust lever" and not throttle? I believe the distinction came about with computerized engine controls such as FADEC. Prior to that the throttle levers regulated the flow of fuel to the engine. With computerized controls, they regulated the percen...

Re: Aircraft positions on ground

That already exists. Even GA planes have fishfinders that show taxiing aircraft in a different format than airborne ones so you know where they are. Not that you'd want to be operating a 172 in weather so bad that you'd need something like that (where you going if engine quits...).

Re: Curious: BA Takeoff Procedures - Gear Retraction

Thanks all, that makes sense.

Re: Curious: BA Takeoff Procedures - Gear Retraction

Related question: to what extent does deceleration rate affect brake heating? Doesn't the same amount of energy need to get dissipated either way? The only thing I can think of that would make a big difference is using more TR or spoilers on a longer runway and thus having to do less braking.

Re: Airbus 32X NEO program: why no length adjustment?

Thread bump on something I've been wondering about: what factors led A and B to pick the lengths that they did? Looking back at history, I'm going to guess the following: A built the 320 as a European 727-200 replacement, and quickly realized that they could extend the range a bit and capture a lot ...

Re: music/movie in cockpit on (ultra) long haul?

This isn't a stupid question, at all. The top brands of headsets generally come with Bluetooth, and pilots of all sorts definitely do listen to music on them during non-sterile portions of flight - though that may not be strictly following the rules at some places. After that Delta MSP overflight, ...

Re: airplane gliding

The 787 glide ratio is supposedly so high it’s proprietary information. I don’t know the exact number. I assume Airbus models are equally efficient. Couldn't one infer the 787's L/D fairly accurately (+/- a few %) based on known cruise engine SFC, thrust, and burn in a variety of gross weight condi...

Re: Delta - payroll optimized luggage/overhead question

A bag in the overhead weighs nothing, since it is built into the weight of a passenger, but in the pit it counts as a bag and weighs somewhere around 30 pounds depending on what their average weight program weights are. It is fascinating how the regulations work. Sounds like the airplane may either...

Re: Cold temperatures and the flight levels

Mmmm yes I'm aware everybody uses 29.92 inHg above FL180, though I'm wondering if even at that same setting do the pressure levels "condense". Basically asking if airplanes flying an IAP have to correct for cold temperatures if marked in the approach chart (and it is cold enough), does so...

Re: Cold temperatures and the flight levels

Adiabatic cooling occurs as an aircraft climbs, this is due to the change in pressure. As an aircraft climbs into the flight levels all aircraft use a standardized altimeter setting to ensure separation. As an aircraft descends out of the flight levels local atmospheric pressure, from the arrival a...

Re: What degree of bank angle is used by jetliners when making large wide turns?

OP, here's a math exercise for you: watch a few of the planes turning base and final, time how long it takes, and get an approximate ground track to get the turn radius. Look up the winds aloft, and then get an idea of the airspeeds. From that, some trig: https://code7700.com/aero_turn_performance.h...

Re: Right and left-handed pilots and side sticks?

Most CFI students, when they transition to the right seat, are able to figure it out pretty quickly. The only real issue is the steep turns, those tend to take a few flights because the sight picture looks different. As a CFI, you often seat hop a few times in a day, and it's not a real issue. Many ...

Re: Airbus A330 and A340 Movements / Write-Off / Retirements / Scrapping Thread - 2022

Did the two Armee d' le Air A340-200s get retired?

Re: Why didn't the Boeing 707 have rudder problems similar to those of the Boeing 737?

The original issue with the 707 rudder on the short-fin models was that it required something like 100 lb of force to move, which is why they added the taller fin, ventral fin, and boost: https://airlinercafe.com/page.php?id=72 I believe the UK regulators were going to refuse certification if they ...

Re: Why didn't the Boeing 707 have rudder problems similar to those of the Boeing 737?

The original issue with the 707 rudder on the short-fin models was that it required something like 100 lb of force to move, which is why they added the taller fin, ventral fin, and boost: https://airlinercafe.com/page.php?id=72 I believe the UK regulators were going to refuse certification if they d...

Re: Which airliners have ram air turbines. Which power hydraulics and which provide electricity?

Fun fact: the #3 A340 flap track canoes on the starboard side is longer to accommodate the RAT: https://upload.wikimedia.org/wikipedia/commons/e/ed/A340-600_clean-wing_bottom_plan-view.jpg Interesting, I would have thought the Port one would be the same size even if not required, for symmetry/drag ...

Re: Which airliners have ram air turbines. Which power hydraulics and which provide electricity?

Fun fact: the #3 A340 flap track canoes on the starboard side is longer to accommodate the RAT:

Re: High power settings on the 727 during approach and landing due to drag for dirty condition or for quick spool up.

The high lift systems on the 727 created a ton of drag as a consequence of their high lift at low speeds, so you needed a decent amount of thrust to keep it stable. More modern aircraft have simpler systems that make less drag, and hence less thrust and noise. The DC10 was not as optimized for short...

Re: Boeing Hints at Next New Jet as It Weighs Tough Engine Decisions

The landing gears stores in the lower horizontal strut. That's a HUGE can of worms IMHO. For one, that totally changes force distribution in that lower strut, from mostly tensile to... to god knows what... No way can the gear be stored, nor be supported by the as pictured lover truss bracing. So I ...

Re: Korean Air looks to rebrand

Let's be honest. I think we all know what direction this rebrand is going. They probably paid millions of dollars to a design firm for something that resembles this thing I crapped out in 20 minutes. https://i.imgur.com/eHtS5rB.png Queue the Marketing Department: The new livery blends the cultural ...

Re: Boeing confirms higher gross weight 787-10

I just hope Boeing can do it without sacrificing CASM at lower ranges. Me too, this is what Airbus learned when they thought they needed to HGW the A346 in response to the B77W, then only offered the HGW version Well Airbus did that (made HGW standard that is) because the A345/6 wasn’t selling and ...

Re: civilian aircraft what if

Coming together nicely!

Re: Are holding patterns used very much anymore and at which airfields?

I’d love to see pilots raised on “glass” enter and fly an intersection hold with dual VORs. I wonder if they teach the TTTTT anymore.... lol My institution does this, ditto steam gauge needle flying. Automation suffers from GIGO (AA965, EK407), and raw-data flying suffers from math errors and instr...

Re: Boeing confirms higher gross weight 787-10

I’m curious what more will need to be done to get the 787 up to 260T and beyond. I imagine thrust increases, and possibly increasing wing dimensions to keep T/O performance from getting out of hand. I think an increase in wing dimensions would help, but of course it's very costly. It's interesting ...

Re: Do gate size restrictions matter for freighters

Gate space is definitely a factor for cargo ops, especially the box haulers with big hubs like Fedex and UPS. Whenever you have a bunch of planes arrive, then rescramble the boxes and re-load them, travel times and distances to and from all the planes becomes an issue. From an efficiency standpoint,...

Re: Learjet Crash December 27 2021 in San Diego/ Gillespie - audio/video

We all look at charts, but FAA 8260-5 is the document that is the source for the charts. https://www.faa.gov/aero_docs/acifp/NDBR/2017062233337302001-SEE-NDBR/CA_SAN%20DIEGO%20EL%20CAJON_LD_SEE_CORRECTED.pdf It references Part 97 making compliance with the approach a regulation, not just a suggesti...

Re: civilian aircraft what if

Got the first 2 revell boeing 747 I ordered yesterday. The cutaway, I'm now hesitating between British airways and SAS because british airways had a weird policy on modelling specific aircraft of their fleet in the 60', revell at the time couldn't put specific registration letters on their 200 deca...

Re: Altimeters, static pressure, and lift

Anybody who thinks there are no pressure differentials on boat rudders needs to go sail a Laser dinghy. Get on a broad reach in 20 knots of breeze, let the boat heel over 30 degrees, and then pull the tiller to try and maintain course. Spoiler alert: you'll hear a "khkhkh" sound as the up...

Re: Altimeters, static pressure, and lift

Anybody who thinks there are no pressure differentials on boat rudders needs to go sail a Laser dinghy. Get on a broad reach in 20 knots of breeze, let the boat heel over 30 degrees, and then pull the tiller to try and maintain course. Spoiler alert: you'll hear a "khkhkh" sound as the upw...

Re: civilian aircraft what if

No idea, I'd give it a dark gray to make sure it's not translucent, or do a gray primer guide coat to accomplish the same.

Re: civilian aircraft what if

If you're referring to the rear door molding, that's what we in the US refer to as "engraved panel lines," as opposed to "raised panel lines" that used to be on a lot of older kits because that was easier to produce, but forced the modeler to scribe them all in afterward.

Re: United CEO Tells Senate Panel that 100 Regional Jets are Grounded Because of the Pilot Shortage

Let's be clear about this.... There is not a pilot shortage. There is, however, a shortage of pilots willing to fly regionals for what United wants to pay them, when so many other opportunities are available. It is not 2008, anymore. Bingo. He should go talk to his yield management team about how s...

Re: A380 lack of cargo carrying capacity versus twins

In a nutshell: 1. Both planes are about the same length. 2. The A380 is taller/wider and thus has more taper front and rear that eats into cargo. 3. The A380 is heavier and thus has a larger wing. This wing needs to fit in an 80m box, so to get enough area, the chord is much longer, which means the ...

Re: Complicated, by design. But is it really?

The first bit has already been gradually happening for decades. Very interesting, thanks! I'm not a fan of direct autoflight implementation of datalink clearances. It removes a rather significant safety net. An intermediate step, which is already happening, is automatic entry of received parameters...