For Cone Layout Version 2.0.5 Hit |BEST|
Irta Boccanfuso
Cone Layout is a program to unfold a frustum of a cone and generate a sheet cutting layout or flat pattern projection that can be rolled or bend up into a truncated cone shape. Either side of the truncated cone can be tilted. To help you visualise the cone you are editing, a rotating 3D model shows the dimensions.
The layout pattern can be printed directly on paper for use as a template for cutting out the shape from a plate of metal. Or you can write the layout pattern to an AutoCAD DXF file which is the world standard among computer controlled cutters. Other supported file formats are Encapsulated PostScript (EPS) or a plain text file with coordinates.
The program has a minimization routine, which will minimize the amount of wasted material by varying the seam along which the cone is cut open. The program automatically selects the smallest rectangular piece of material big enough to hold the pattern.
Cone Layout has initially been designed for building an exhaust pipe for a racing motorcycle. The traditional way to accomplish this is by developing an exhaust pipe consisting of several truncated cones or conic sections including cylinders. To conform to the shape of the motorcycle frame the conic sections will meet at a variety of angles and will be of different lengths.
You can unfold anything into a flat pattern once you convert it to sheetmetal as long as it has a uniform cross-section. However, what I want to do is make a pattern in the flat, convert it to sheetmetal (primarily so I can fiddle with the k-factor, otherwise the warp tool would be fine for this), and then bend it into a cone. I had hopes of maybe getting one of the vertices of the bend line to offset from the surface of the part at an angle I can control, but the bend line seems firmly constrained to the surface plane of the part, other ways I've tried to bend a flat into a cone while maintaining neutral axis control have not worked. The part is not actually sheetmetal, but the k-factor adjustment is invaluable.
If someone has a sneaky way of acheiving this (1: control over k-factor 2: be able to add features in the flat and have them bend with the rest of the part, 3: bend into a cone instead of a cylinder) or I'm just missing a checkbox somewhere, I'd be interested.
A cone, optionally with the top cut off. (In that case, it's called a frustum). Can be used to help create the geometry for a beaker, vase, party hat or lamp shade. If you'd like a real cone, just use 0(zero) for the Top Diameter.
Color vision is facilitated by distinct populations of cone photoreceptors in the retina. In rodents, cones expressing different opsin photopigments are sensitive to middle (M, 'green') and short (S, 'blue') wavelengths, and are differentially distributed across the retina1,2. The mechanisms that control which opsin is expressed in a particular cone are poorly understood2,3, but previous in vitro studies implicated thyroid hormone in cone differentiation4,5. Thyroid hormone receptor β2 (TRβ2) is a ligand-activated transcription factor that is expressed in the outer nuclear layer of the embryonic retina6,7. Here we delete Thrb (encoding Trβ2) in mice, causing the selective loss of M-cones and a concomitant increase in S-opsin immunoreactive cones. Moreover, the gradient of cone distribution is disturbed, with S-cones becoming widespread across the retina. The results indicate that cone photoreceptors throughout the retina have the potential to follow a default S-cone pathway and reveal an essential role for Trβ2 in the commitment to an M-cone identity. Our findings raise the possibility that Thrb mutations may be associated with human cone disorders8.
Given the problem of the aerodynamic design of the nose cone section of any vehicle or body meant to travel through a compressible fluid medium (such as a rocket or aircraft, missile, shell or bullet), an important problem is the determination of the nose cone geometrical shape for optimum performance. For many applications, such a task requires the definition of a solid of revolution shape that experiences minimal resistance to rapid motion through such a fluid medium.
A very common nose-cone shape is a simple cone. This shape is often chosen for its ease of manufacture. More optimal, streamlined shapes (described below) are often much more difficult to create. The sides of a conic profile are straight lines, so the diameter equation is simply:
A bi-conic nose cone shape is simply a cone with length L1 stacked on top of a frustum of a cone (commonly known as a conical transition section shape) with length L2, where the base of the upper cone is equal in radius R1 to the top radius of the smaller frustum with base radius R2.
Next to a simple cone, the tangent ogive shape is the most familiar in hobby rocketry. The profile of this shape is formed by a segment of a circle such that the rocket body is tangent to the curve of the nose cone at its base, and the base is on the radius of the circle. The popularity of this shape is largely due to the ease of constructing its profile, as it is simply a circular section.
If the chosen ρ is less than the tangent ogive ρ and greater than half the length of the nose cone, then the result will be a secant ogive that bulges out to a maximum diameter that is greater than the base diameter. The classic example of this shape is the nose cone of the Honest John.
The profile of this shape is one-half of an ellipse, with the major axis being the centerline and the minor axis being the base of the nose cone. A rotation of a full ellipse about its major axis is called a prolate spheroid, so an elliptical nose shape would properly be known as a prolate hemispheroid. This shape is popular in subsonic flight (such as model rocketry) due to the blunt nose and tangent base.[further explanation needed] This is not a shape normally found in professional rocketry, which almost always flies at much higher velocities where other designs are more suitable. If R equals L, this is a hemisphere.
This nose shape is not the blunt shape that is envisioned when people commonly refer to a "parabolic" nose cone. The parabolic series nose shape is generated by rotating a segment of a parabola around a line parallel to its latus rectum. This construction is similar to that of the tangent ogive, except that a parabola is the defining shape rather than a circle. Just as it does on an ogive, this construction produces a nose shape with a sharp tip. For the blunt shape typically associated with a parabolic nose, see power series below. (The parabolic shape is also often confused with the elliptical shape.)
The power series includes the shape commonly referred to as a 'parabolic' nose cone, but the shape correctly known as a parabolic nose cone is a member of the parabolic series (described above). The power series shape is characterized by its (usually) blunt tip, and by the fact that its base is not tangent to the body tube. There is always a discontinuity at the joint between nose cone and body that looks distinctly non-aerodynamic. The shape can be modified at the base to smooth out this discontinuity. Both a flat-faced cylinder and a cone are shapes that are members of the power series.
For aircraft and rockets, below Mach .8, the nose pressure drag is essentially zero for all shapes. The major significant factor is friction drag, which is largely dependent upon the wetted area, the surface smoothness of that area, and the presence of any discontinuities in the shape. For example, in strictly subsonic rockets a short, blunt, smooth elliptical shape is usually best. In the transonic region and beyond, where the pressure drag increases dramatically, the effect of nose shape on drag becomes highly significant. The factors influencing the pressure drag are the general shape of the nose cone, its fineness ratio, and its bluffness ratio.[2]
Many references on nose cone design contain empirical data comparing the drag characteristics of various nose shapes in different flight regimes. The chart shown here seems to be the most comprehensive and useful compilation of data for the flight regime of greatest interest.[3] This chart generally agrees with more detailed, but less comprehensive data found in other references (most notably the USAF Datcom).
In many nose cone designs, the greatest concern is flight performance in the transonic region from Mach 0.8 to Mach 1.2. Although data are not available for many shapes in the transonic region, the table clearly suggests that either the Von Kármán shape, or power series shape with n = 1/2, would be preferable to the popular conical or ogive shapes, for this purpose.
The ratio of the length of a nose cone compared to its base diameter is known as the fineness ratio. This is sometimes also called the aspect ratio, though that term is usually applied to wings and tails. Fineness ratio is often applied to the entire vehicle, considering the overall length and diameter. The length/diameter relation is also often called the caliber of a nose cone.
At supersonic speeds, the fineness ratio has a significant effect on nose cone wave drag, particularly at low ratios; but there is very little additional gain for ratios increasing beyond 5:1. As the fineness ratio increases, the wetted area, and thus the skin friction component of drag, will also increase. Therefore, the minimum drag fineness ratio is ultimately going to be a trade-off between the decreasing wave drag and increasing friction drag.
The futures cone is a useful foresight tool that could lend itself nicely to co-creative workshops. However, its original visual representations do not fit this type of usage. So we created this alternative version of the futures cone, to enable you to facilitate these types of workshops.
An inlet cone, as far as I know, is a component on an engine to guide the intake air smoothly into the compressor stage of a jet turbofan engine, it performs as a fairing(aerodynamic covering)of the axis on which the intake fan is installed, to improve the aerodynamic efficiency. *The engines are all on subsonic airliners.
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