The World Of Aviation

Ailerons can be used to generate a rolling motion for an aircraft. Ailerons are small hinged sections on the outboard portion of a wing. Ailerons usually work in opposition: as the right aileron is deflected upward, the left is deflected downward, and vice versa. This slide shows what happens when the pilot deflects the right aileron upwards and the left aileron downwards.

The ailerons are used to bank the aircraft; to cause one wing tip to move up and the other wing tip to move down. The banking creates an unbalanced side force component of the large wing lift force which causes the aircraft's flight path to curve. (Airplanes turn because of banking created by the ailerons, not because of a rudder input.

The ailerons work by changing the effective shape of the airfoil of the outer portion of the wing. As described on the shape effects slide, changing the angle of deflection at the rear of an airfoil will change the amount of lift generated by the foil. With greater downward deflection, the lift will increase in the upward direction. Notice on this slide that the aileron on the left wing, as viewed from the rear of the aircraft, is deflected down. The aileron on the right wing is deflected up. Therefore, the lift on the left wing is increased, while the lift on the right wing is decreased. For both wings, the lift force (Fr or Fl) of the wing section through the aileron is applied at the aerodynamic center of the section which is some distance (L) from the aircraft center of gravity. This creates a torque

T = F * L

about the center of gravity. If the forces (and distances) are equal there is no net torque on the aircraft. But if the forces are unequal, there is a net torque and the aircraft rotates about its center of gravity. For the conditions shown in the figure, the resulting motion will roll the aircraft to the right (clockwise) as viewed from the rear. If the pilot reverses the aileron deflections (right aileron down, left aileron up) the aircraft will roll in the opposite direction. We have chosen to name the left wing and right wing based on a view from the back of the aircraft towards the nose, because that is the direction in which the pilot is looking.

When you travel on an airliner, watch the wings during turns. The pilot rolls the aircraft in the direction of the turn. You will probably be surprised at how little deflection is necessary to bank (roll) a large airliner. But be warned that there is a possible source of confusion on some airliners. We have been talking here about rolling the aircraft by using a pair of ailerons at the very trailing edge of both wings to increase or decrease the lift of each wing. On some airliners, the aircraft is rolled by killing the lift on only one wing at a time. A plate, called a spoiler, is raised between the leading and trailing edges of the wing. This effectively changes the shape of the airfoil, disrupts the flow over the wing, and causes a section of the wing to decrease its lift. This produces an unbalanced force with the other wing, which causes the roll. Airliners use spoilers because spoilers can react more quickly than ailerons and require less force to activate, but they always decrease the total amount of lift for the aircraft. It's an interesting trade! You can tell whether an airliner is using spoilers or ailerons by noticing where the moving part is located. At the trailing edge, it's an aileron; between the leading and trailing edges, it's a spoiler.


.

Wingtip Vortices

Today we are going to talk about Wake Turbulence and Wing Tip Vortices. Wake turbulence is best explained as a spinning mass of air, originating from the wingtips of a large heavy airliner, trailing backwards that may cause following aircraft to enter an "unusual attitude" of which recovery is doubtful. This usually occurs during still or light air conditions but WestWind Captains should be aware of it at all times.

As the wings of a large airliner pass through the air, lift occurs when the high pressure under the wing tries to fill a vacuum of the low pressure on top of the wing. As a byproduct of this lift, some air will circulate causing a "rolling effect" to take place behind the wingtips. What happens is two vortices (the left wing clockwise and the right wing counterclockwise as viewed from behind the airliner looking forward) develop and continue to spin until their energies are reduced. Most of the energy is within a few feet of the center of each vortex but pilots should avoid a region within 100 feet of the vortex core. Airliners which are heavy and in the clean configuration give off the most intense vortices. Captains, flying an airliner, with a shorter wingspan and lighter weight, trailing a "heavy", should be alert of the possibility of wake turbulence.

Wing tip vortices start at the moment a "heavy" leaves the ground. Prior to takeoff or landing pilots should note the point of liftoff or touchdown of a "heavy"(you can see this using SB and MP). What is needed, in this situation, is to takeoff or land before wingtip vortices can become a threat to your airliner. To do this we must takeoff before the rotation of the "heavy" ahead of us and, (if landing) land at a point on the runway further down from where the "heavy" has touched down.

Wingtip vortices trail upward and outward from the wingtips of a "heavy" and spin in a counterclockwise motion. When they reach their highest point (depending on weight and speed of the "heavy") they start to sink towards the ground. Once they hit the ground they will roll laterally at about 2 or 3 knots. A crosswind may keep the upwind vortice in the runway area for an extended time. The worst condition is a light quartering tailwind. In this case the upwind vortice will move towards and up the runway making the judgment of where to touchdown difficult.

This video shows how wingtip vortices generate. It is simple and to the point:

If you were following a "heavy" on an ILS approach, it is possible to experience wake turbulence as you proceed down the glideslope. In this case you would fly your approach descending "one dot" below the glideslope center position (fly above the glideslope). In a previous post I stated that the autopilot should be used down to minimums. Here is one case where you would "hand fly" the approach - keeping your glideslope path "one dot below" to avoid any wake turbulence.

It is possible to experience wake turbulence while you are on the ground waiting to take off. For example, if you were at the hold short line on the taxiway leading to the runway threshold and it was downwind of an approaching "heavy" then you could experience wake turbulence as the "heavy" lands. In this case the hold short lines of the taxiway are 280 feet from the centerline of the runway (for designated runways for "heavies").

Another case, that could "ruin your day", is doing a "missed approach" following a "heavy" that also "missed". In this case it would be wise to fly your missed approach at your best angle of climb airspeed to get to your initial missed approach altitude.

The controllers responsibility (for VFR Flight) is to allow for a two minute "hold time" before clearance to takeoff behind a "heavy". In cases where the Captain accepts a "visual" approach, it is the Captain's responsibility to stay clear of any wake turbulence condition. In all cases the Captain is the final authority for safe flight.

.

Malaysia Airlines has been trialling AeroMobile's mobile phone and data services over the last few weeks, garnering the distinction of becoming the first carrier in Asia to offer such services.

The AeroMobile system was installed on a Malaysia Boeing 777-200 aircraft during a routine maintenance check.

Malaysia Airlines managing director and CEO Dato Seri Idris Jala says the trial will be conducted to gauge passenger behaviour and acceptability. "If the evaluation findings are positive, we aim to roll out the system throughout the remainder of our widebody aircraft fleet next year."

I asked AeroMobile to send along a photo of its equipment installed on a 777.

The image below shows part of the installation (three of the six boxes), installed on the 'E7 rack' in the crown of the aircraft cabin above the ceiling panels.

The AeroMobile equipment (three avionics units in this shot) is the equipment to the left of the orange boxes. The two thick black cables are the 'leaky feeder' ('radiating RF cables') which are installed down both sides of the full length of the aircraft cabin providing a signal to passengers' mobile phones

KUALA LUMPUR Malaysia's AirAsia today abolished fuel surcharges on all its flights and said it will give away half a million free tickets next year in an attempt to lure travelers amid the global slowdown.

AirAsia Chief Executive Tony Fernandes said the region's biggest budget carrier will offer 500,000 free seats for travel between June 22 and Oct. 24, 2009, on all its domestic and international destinations.

"It will be completely free. Passengers will only have to pay airport tax,'' Fernandes told a news conference.

He said the recent steep drop in fuel prices has allowed AirAsia to adopt the bold strategy, adding that the loss of revenue should be offset by higher ticket sales, which will also be bolstered by new marketing strategies.

Fernandes said AirAsia is the first carrier in the world to abolish fuel surcharges, which became a standard industry practice a few years ago as oil prices rose on their way to peaking at nearly $150 a barrel in mid-July. But since then, crude prices have tumbled because expectations that slower global growth will mean less demand.

"We want to do is get rid of these surcharges,'' Fernandes said. "The best way to do it is aggressive marketing and low fares.''

Eliminating the surcharges is expected to cost AirAsia about 940 million ringgit ($63 million) a year.

Fernandes said the move will boost Malaysia's economy as well as domestic and regional tourism by encouraging travel.

When AirAsia started in December 2001, it focused on flying within Malaysia. It has since expanded to Southeast Asia and China, and is scheduled to launch flights to India next month.

Malaysian Domestic Trade and Consumer Affairs Minister Shahrir Samad praised the decision.

"Anything that reduces costs to consumers and keeps money in their pocket gets my support,'' he told reporters after the announcement. "What we need now is optimism instead of grumbling and quarreling.''

Fernandes added that he could not guarantee that the removal of fuel surcharges would not hit AirAsia's profits, but said the company does not anticipate that would happen. He refused to say what the possible losses might be.

He noted AirAsia does not hedge its fuel purchases like other airlines do. To protect against the possibility of prices going up, some carriers make advance orders at current prices.

Fernandes said AirAsia will not implement a corresponding increase in base ticket prices with the removal of fuel surcharges, but said he could not guarantee that the surcharge would not be re-imposed if oil prices surge again.

"It would be foolish of me to say that fuel surcharges will not be imposed again but we will resist it for as long as possible,'' Fernandes said.

Wet Paper Sack

Did you know that many airplanes use paper for strength?

Imagine a PB&J sandwich. Now imagine that the 'bread' is made of fiberglass, and the Jam is made of a thick slice of perforated paper. If you do like I do when I eat a PB&J, then you smash it really thin before eating it. This is, in essence what composite honeycomb is. Have a look:

Now, having a thick core like this is actually a 'good thing'. It keeps the structure light and gives it strength. These are also 'good thing's for airplanes.

But there's a problem. When paper gets wet, what does it do? It falls apart, right? that means that if water somehow got into your composite then your core can fail, the composite colapses and *poof*, no more structural member. Now, normally, well made composites are sealed from the atmosphere. H2O can't get in, and everything is fine.

Just for fun, though, let's imagine that there's a small crack in the composite. It's tiny, hardly even visible; in fact, you can't see it but it's there. Let's say this composite is part of an airplane that does lots of takeoffs in a hot tropical climate. At 30,000 ft the air temperature is -50. What might happen to the warm, moist air that gets into the composite? It condenses, right? Right. As Julia Roberts once said 'Big mistake. Huge!' Now do this, say 500 more times, and now the water starts to pool in the composite. Check this out:




The green sections represent water in the composite. If this were a paper core, then it wouldn't be long before that core fails, and quickly thereafter, the rest of the composite. And failure or delamination, as it's called, is caused by not just water, but almost any type of fluid that can saturate the paper. Here's a report from the TSB of Canada detailing the delamination due to hydraulic fluid:

http://www.tsb.gc.ca/en/media/fact_sheets/A05F0047/recs_a0606_goudou.asp

In order to find this kind of problem, you pretty much have to x-ray or scan the structure. Have YOU seen any x-ray or scanning equipment at the airport? (other than at security, smart***) How does the airline know if this is happening? Short answer: in my opinion, they don't. At least not until a thorough inspection happens. The fix is problematic, too. Heating up the composite can blow up the sealed water, destroying the structure, and trying to suck it out is no good either. Best just to not let it happen. The FAA is starting to take a closer look at maintenance procedures, lately, and trying to determine if more and closer inspection needs to be done to prevent water ingress.

In the meantime, we keep flying.

Btw, what happens to freezing water as it cools? it EXPANDS, right? Right....Happy thoughts until next time.
























































































.

Turtle Airships

Picture (click to enlarge):

Subjects: Why "turtle"?

Because it has a SHELL. A hard, facted, durable, all weather, strong shell. Unlike blimps or zeppelins; which are built as glorified balloons...which can leak and tear and fall apart in sunlight.

Because it is FAST. The incrongruity of a fast Turtle is meant to surprise and intrique. Blimps and zeppelins are slow because of the flexibility and lack of structural strength of their fabric and laminate envelopes. The Turtle shell makes it strong, rigid......and fast. To 200mph.........

Because it is AMPHIBIOUS. Blimps and zeppelins land and tie up at mooring masts. They need large ground crews to land. The Turtle airship, on the other hand, can land anywhere. It can land on an unprepared field, or land in the water.........just like a turtle.

Because it looks like a turtle. The bow and stern planes give the impression of a turtles' four legs sticking out from its' shell. The position of the three bottom hulls appears much like a turtles' head and forelimbs underneath its' shell.

Because its' "slow, but sure". At one third the speed of a large jet......it is safe and steady. No turbulence. No banking or climbing like an airplane. Quiet. Calm. No jet lag. Comfortable........with walk around room and private staterooms. Totaly safe. No high speed make-or-break approaches to runway landings. No wind shear dangers. Immune to the same bombing, shooting, missiles, or hi-jack attempts that threaten airplanes.

Because it's SOLAR POWERED. Just as a cold blooded turtle climbs out of the water and soaks up the sun.........so Turtle Airships collect sunlight in photovoltaic solar cells in order to generate electricity for power. With fuel cells and a bio-diesel back up capability, it makes the Turtle airship into a truly "green" technology; and changes flight forever.

Because who could ignore, or ever forget......A FLYING TURTLE ??!!
















Eco-friendly Turtle Airship design

intro: It certainly doesn’t hurt to have, eco-friendly one like the Turtle Airship that Darrell Campbell, the designer of Millennium Airship is working on. The picture is that of a Millenium Airship.

Subjects: Eco-friendly Features:

• The outer frame-work of the Airship to be made of titanium, aluminum or stainless steel would be incorporated with amorphous thin films of photovoltaic cells to harness solar energy.

• The electricity produced runs the electric motors and propellers of the Airship.

• The electric motors use lighter super conducting magnets rather than copper wires.

• The excess energy produced in the day is used to split water into hydrogen and oxygen, to function as fuel cell as an alternate during night and cloudy conditions.

• Bio-diesel powered generators are also built-in to circumvent any remote chances of solar and fuel cells’ failure.



















Millennium Airship, Inc.


Picture (click to enlarge): Millennium Airship, creators of a revolutionary new hybrid heavy lift aircraft, the SkyFreighter.

Intro: Millennium Airship Inc. founded in August 1998. The primary goal of the company is to design, engineer, build, market and operate the world's first HEAVY-LIFT AIR VEHICLE that is: lighter-than-air, all-weather, amphibious semi-rigid, multi-mission, hybrid. The key feature of this aircraft will be in that it is so maneuverable, that it can operate in and out of virtually anywhere (land or sea) where there is enough space to accommodate its size.

Subjects: DARPA (Defence Advanced Research Projects Agency) WALRUS PROJECT

"Fort to the Fight" Unit of Action - At a meeting organized by the Joint Chiefs of Staff, JCS J-4 Mobility Division in April 2001 at the Pentagon, the desire for a prototype demonstration of "SkyFreighter" was requested by all branches attending. We fully believe this airship and it's unique capabilities will provide our Armed Forces with a "mission" diverse transport that can get the troops, armor and supplies to the point of conflict. And, provide Homeland Security Agency with a smaller version of "SkyFreighter" for Extended Duration (3 days) Maritime Coastal Patrol and Drug Interdiction. The military requires an air vehicle that can lift 500 plus tons, cruise at 100 mph, travel 12000 miles in 7 days, and fly at altitudes up to 20,000 feet. The Millennium Airship, Inc DARPA Proposal was mailed on March 30 to DARPA. Even though the DARPA project has been cancelled for now, all branches of the military and Homeland Security have definite requirements for this aircraft.

Benefits

1) Because of its massive lifting capacity, SkyFreighter can bring the "Fort to the Fight."
2) SkyFreighter can land almost anywhere, land or sea. No airport or ground support required.
3) Unlike all other airships, SkyFreighter does not need ballast transference when loading or unloading.


Picture (click to enlarge):

Military Blimps

4 New 'Blimp' Designs Bring Return of the Airship

Picture (click to enlarge): Aeros’s new ballast-free airship design may soon be tested for the Pentagon in a demonstration craft.

Intro: Always on the verge of a seeming comeback, airships are back in the spotlight, touting new technologies. The Defense Advanced Research Project Agency recently announced funding for an innovative, ballast-free airship technology created by Aeros Aeronautical Systems, based outside Los Angeles. The Aeroscraft ML866's potentially revolutionary Control of Static Heaviness system compresses and decompresses helium in the 210-ft.-long envelope, changing this proposed sky yacht's buoyancy during takeoff and landings, Aeros says. It hopes to end the program with a test flight demonstrating the system. Other companies are planning their own first flights within the next few years. Each has a design that it promises will launch a new era of lighter-than-air transportation.


Picture (click to enlarge): HAA


Picture (click to enlarge): SA-60


Picture (click to enlarge): Skycat-20





































Boeing to Build SkyHook Neutrally Buoyant Rotorcraft


Picture (click to enlarge): SkyHook Lifting Off (Source: Boeing)

Intro: Boeing and SkyHook International have announced that they intend to team up for a new aircraft called the JHL-40 (Jess Heavy Lifter). The JHL-40 is a new commercial heavy lift aircraft that is intended to transport equipment and materials in remote and harsh regions such as Alaska or the Canadian Arctic.

Boeing will build the JHL-40 neutrally buoyant rotorcraft for SkyHook, which will own, maintain and operate the JHL-40 for commercial clients.

Subjects: The aircraft utilizes a helium filled envelope that provides enough lift to make the JHL-40 aircraft, engines, and crew neutrally buoyant. The four rotors will generate lift that is only needed to support the payload. According to Boeing and SkyHook, the JHL-40 will be able to lift loads as heavy as 40 tons and transport them up to 200 miles without refueling.



















Boeing's New Heavy Lifter


Picture (click to enlarge): SkyHook in Transit (Source: Boeing)

Intro: You can bet the Army will be looking into this for their Joint Heavy Lift platform. Believe it or not, something very similar to this is discussed in great detail in the original Defense Science Board report on Sea Basing.

When you start thinking about this technology, and the maturity potential, the absence of a military commitment to date is curious. We tend to think there is a lot of capability here long term.





Picture (click to enlarge): From Giant Blimp, Deflated [>]. A quote - No! Nooooo! Say it ain't so, Darpa! The Walrus program -- the fringe-science agency's awesomely, almost insanely, ambitious plan to build an aircraft carrier-sized blimp -- is over, Defense Technology International discovers.



Picture (click to enlarge):

From BAE SYSTEMS FLOATS AUTONOMOUS SYSTEM AT FARNBOROUGH INTERNATIONAL [>]. A quote - A 22 meter long airship, originally developed by balloonist and adventurer Per Lindstrand, could become the latest addition to BAE Systems growing portfolio of autonomous systems. The GA22 airship, perfect for deployment into roles such as communications relay stations, will be updated and adapted to carry payloads, such as high tech surveillance equipment at up to 150 kilograms in weight, to heights of more than 6,500 feet. BAE Systems plan to integrate their existing Unmanned Autonomous Systems into the GA22 making the technology more accessible to potential users.





Picture (click to enlarge):

From Time for TARS Along USA’s Southern Borders [>]. A quote - An aerostat is a lighter-than-air craft that relies on a ground tether for movement and often for power as well, as opposed to blimps which are self-powered, free-flying craft.





Picture (click to enlarge):

From Where Did All the Airships Go? [>]. A quote - A few years ago, the Air Force was all excited about "near space," the area between 65,000 and 325,000 feet above sea level. The plan was to put lighter-than-air ships up in this region above the jet stream for persistent surveillance. I, too, got excited, because I love everything and anything to do with lighter-than-air vehicles. But one by one, many of the near space efforts have been killed off or scaled back (although some appear to go on, as Bill Sweetman notes over at Aviation Week's ARES blog).

Hybrid Airships

Airlines.net - Lockheed Martin P-791


Picture (click to enlarge): Picture of the Lockheed Martin P-791 aircraft. (Lockheed Martin's Secretly Built Airship Makes First Flight (Feb 5, 2006) [>])

Intro: N791LM (cn 0001) I was at the Blackbird Air Park when suddenly this black project hybrid airship took off. It has been secretly built by Skunkworks as a heavy-load carrier. To gain more span to act like a wing, the P-791 is three pressurized lobes joined together. It uses four air cushions as landing gear, located on the outer lobes. It appears to have four propellers-two at the tail and two on the sides. A hybrid airship derives most of its lift by lighter-than-air gas, the rest by its shape and span.

Subjects: From Wikipedia [>]: The P-791 is an experimental aerostatic/aerodynamic hybrid airship developed by Lockheed-Martin corporation. The first flight of the P-791 was made on 31 January 2006 at the company's flight test facility on the Palmdale Air Force Plant 42. According to press reports, the designation "P-791" has no particular meaning.

Although Lockheed-Martin is developing a design for the DARPA project WALRUS, the company claims that the P-791 is unrelated to WALRUS. Nonetheless, the design represents an approach that may well be applicable to WALRUS. Some believe that Lockheed-Martin has used the secret P-791 program as a way to get a "head-start" on Worldwide Aeros Corporation, the other Phase I WALRUS competitor.



Picture (click to enlarge):

From The Hybrid Aircraft Flies - A Press Release According to Aviation Week [>]



Picture (click to enlarge):

From It's a hovercraft, it's a blimp... [>]. A quote - It's an experimental craft called the P-791, made by Lockheed-Martin. The lumbering take-offs and landings are curious. It's alleged to be over 60 meters (~200 feet) long.

Civilian Dirigibles

Picture (click to enlarge): From Luxury Airship Filled With Helium, Rich People [>]



Picture (click to enlarge): From As-Yet Unbuilt Aeroscraft ML866 Nonetheless Officially Launched [>]



Picture (click to enlarge): From Blimp News! The Strato Cruiser Luxury Blimp Concept Design [>]



Picture (click to enlarge): From Zeppelins are Back, Too [>]





Picture (click to enlarge): From Alameda Naval Air Museum [>]. Goodyear Blimp "Spirit of America" (N10A), Photo by John Shupek



Picture (click to enlarge): From Horizon blimp one of just 20 in the world [>].The Horizon Blue Cross Blue Shield of New Jersey airship will cruise the state through October.



Picture (click to enlarge): From The future of hyperblimps (and some necessary background) [>]



Picture (click to enlarge): From Blimp catches some eyes on Day 1 [>]. DAVID AHNTHOLZ / Daily News. The Ginn Resorts blimp circles over Quail West on Friday during the first round of The ACE Group Classic.



Picture (click to enlarge): From Inventors to Start Work on Second Personal Blimp [>]



Picture (click to enlarge): From Seeing London by airship [>] gallery. The Stella Artois Airship, built by Zeppelin, prepares for take-off in Essex. Photograph: Peter Macdiarmid/Getty



Picture (click to enlarge): From Seeing London by airship [>] gallery.



Picture (click to enlarge): From Seeing London by airship [>] gallery.



Picture (click to enlarge): From Seeing London by airship [>] gallery.



Picture (click to enlarge): From Solar Power Generating Blimp for Disasters [>]

History and Galleries

Picture (click to enlarge): From Countryman & McDaniel [>]



Picture (click to enlarge): From Welcome to modern-airships.info [>]



Picture (click to enlarge): From official website of Goodyear Blimp [>] gallery.



Picture (click to enlarge): From Alert the amphibious squadron! [>]. A quote - I don’t often link to interesting posts from Modern Mechanix because once you start, where do you stop? But I am compelled to point out this one which reprints an October 1934 Modern Mechanix and Inventions article about an American (presumably) idea for a solar-powered flying airfield.