Airliners have looked largely the same for a long time now. The ongoing hunt for efficiency gains has seen the development of winglets, drag reducing films, and all manner of little aerodynamic tricks to save fuel, and hence money.
The key goal of using a truss-braced wing is to enable an airliner to use a wing much thinner and narrower than usual. These “high aspect ratio” wings are far more efficient than the stubbier, wider wings currently common on modern airliners. But why is aspect ratio so important, and how does it help
If you’ve ever looked at a glider, you will have noticed its incredibly long and narrow wings, which stand it apart from the shorter, wider wings used on airliners and conventional small aircraft. These wings are said to have a high aspect ratio, the ratio between the square of the wingspan and the projected area of the wing itself.
These wings are highly desirable for certain types of aircraft, as lift-to-drag ratio increases with aspect ratio. Any wing that generates lift also generates some drag, but this can be minimized through careful wing design. By making the wings longer and narrower, and thus higher in aspect ratio, the wing tip vortices generated by the wing are weakened. This reduces drag on the plane, and quite significantly so. Continue reading “Truss-Braced Wings Could Bring New Look To Runways Worldwide”→
If you’re a woodworker, you know the value of a good hand plane. A stout model will last a lifetime if properly cared for. [Process X] has now taken us behind the scenes of a Japanese factory that turns out quality hand planes to show us how it’s done.
The video starts at the forge, where steel is attached to soft iron to form a blank that will become the hand plane blade. This is proper blacksmithing, with autohammers and flames akimbo. It’s also a woodworking story, though, with the hand plane bodies themselves carefully prepared for the years of faithful service ahead. We get to see the raw wood roughed into shape and put through the thicknesser, along with the more interesting machining steps that carve out the angled pockets and the blade slot.
The final assembly is great, too, particularly when the pins are nailed in to hold everything in place. The test is the icing on the cake, in which the hand plane peels a perfect contiguous strip from a long piece of lumber.
In the video below, [Daniel] crafts the diminutive tool from a small block of wood by first slicing off a square using a band saw and then switching over to a small hand saw to cut out the individual pieces. These are glued together to make the body of the plane, and the shank of a small drill bit is used to hold down the wedge and blade. All told it’s about 1/2 of an inch long, and is fully functional…or at least, as functional as a 1/2 inch wood plane can be.
[Amy Makes Stuff] has long used a pair of diamond honing blocks to freehand sharpen planes, chisels, and all the other dull things around the shop. Although this method works fairly well, the results are often inconsistent without some kind of jig to hold the blade securely as it’s being sharpened. These types of devices are abundant and cheap to buy, but as [Amy] says in the video after the break, then she doesn’t get to machine anything. Boy, do we know that feeling.
[Amy] was able to make this completely out of stuff she had lying around, starting with a block of scrap aluminium that eventually gets cut into the two halves of the jig. The video is full of tips and tricks and it’s really interesting to see [Amy]’s processes up close. Our favorite part has to be that grippy knob that expands and contracts the jig. [Amy] made it by drilling a bunch of holes close to the outside edge of a circle, and then milled away the edge until she had a fully fluted knob. Once she had the jig finished, she upgraded her honing blocks by milling a new home for them out of milky-white high-density polyethylene.
Once upon a time, bailing out of a plane involved popping open the roof or door, and hopping out with your parachute, hoping that you’d maintained enough altitude to slow down before you hit the ground. As flying speeds increased and aircraft designs changed, such escape became largely impossible.
Ejector seats were the solution to this problem, with the first models entering service in the late 1940s. Around this time, the United Kingdom began development of a new fleet of bombers, intended to deliver its nuclear deterrent threat over the coming decades. The Vickers Valiant, the Handley Page Victor, and the Avro Vulcan were all selected to make up the force, entering service in 1955 through 1957 respectively. Each bomber featured ejector seats for the pilot and co-pilot, who sat at the front of the aircraft. The remaining three crew members who sat further back in the fuselage were provided with an escape hatch in the rear section of the aircraft with which to bail out in the event of an emergency.
A plane is a tool familiar to all woodworkers, used to shape a workpiece by hand by shaving away material. Regular planes are two-handed tools available at all good hardware stores. For finer work, a finger plane can be useful, though harder to find. Thankfully, [Daniel] put together a video showing how to make your own.
[Daniel]’s build relies on stabilized wood, useful for its density and consistent quality, though other woods work too. A 6″ pen blank is enough to make a pair of matching finger planes. A block and two side panels are cut out from the material, with attention paid to making sure everything remains square for easy assembly. The parts are glued together with a block set at the desired cutting angle for the plane. With the assembly then tidied up on the bandsaw and sander, [Daniel] installs the cutting blade. This can be made from a larger standard plane blade, or a cutdown chisel can be pressed into service. The blade is held in place with a wooden wedge beneath a metal pin. The pin itself is crafted from an old drill bit, cut down to size.
It’s a useful tool for doing fine plane work, for which a full-size tool would be ungainly. We can imagine it proving particularly useful in producing accurate scale models in smaller sizes. If you’re big into woodworking, consider giving your tools a good sharpen on the cheap, too. Video after the break.
The RC world was changed forever by the development of the lithium-polymer battery. No longer did models have to rely on expensive, complicated combustion engines for good performance. However, batteries still lack the energy density of other fuels, and so flying times can be limited. Aiming to build a drone with impressively long endurance, [Игорь Негода] instead turned to hydrogen power.
With a wingspan of five meters, and similar length, the build is necessarily large in order to carry the hydrogen tank and fuel cell that will eventually propel the plane, which uses a conventional brushless motor for propulsion. Weighing in at 6 kilograms, plenty of wing is needed to carry the heavy components aloft. Capable of putting out a maximum of 200W for many hours at a time, the team plans to use a booster battery to supply extra power for short bursts, such as during takeoff. Thus far, the plane has flown successfully on battery power, with work ongoing to solve handling issues and determine whether the platform can successfully fly on such low power.