Blokker I/C ignition A good spark is crucial for an IC engine like the Puppy to run reliably and that is often a headache for mechanical orientated model builders for various reasons. Lack of knowledge and experience is one cause but also dimensions, availability, the price, the complexity of the systems or components can all be obstacles. I myself belong also to this category of model builders and I have been wrestling with this problem for as long as I have made IC model engines. Some alternatives 1. In fact, this is a high tension transformer with a short and thick primary coil and a very long and thin secondary coil. (‘points’) that is driven by a cam. On the picture above two examples of classic motor bike high tension coils (bobbin) with diameters of about 40mm and 140mm length. the sparks are weak or not at all present then and they become very hot. 2. Unfortunately, it did not work well with all my other model engines. 3. My experiments with the Blokker circuit Some general comments 1. 3.
Gears- Gear Efficiency Introduction Important Note: The equations used are mainly derived from the technical information provided in the SDP/SI technical library see links below. I recommend that for serious work the linked information is more suitable. The efficiency of a gear system is simple calculated as the [output shaft power /Input shaft power ].100 %. The output power is the (input power - the power losses). The notes below relate primarily to estimating /calculating the the part of the efficiency of gear trains which is associated with the tooth friction. A simple table is provided below showing the efficiencies of various gear types. Symbols Spur Gears / Helical Gears Considering a spur gear a good first approximation for average operating conditions is that the power loss at each mesh can be approximated as P% of the potential power transmitted through the mesh. Clarification of formula terms. Worm Gears Chart of Worm Gear Efficiency μ = 0,04 vs-0,25 vs = sliding velocity (m/s) Epicyclic Gears
Modern History of Wire Rope Modern History of Wire Rope by Donald Sayenga It wasn't until recent history (the 1600-1700s) that most of the technical breakthroughs in the modern history of wire rope were achieved in Europe. Early German and English Ropes The first operative wire ropes of the modern era, employed in vertical shafts as hoisting cables in the Harz Mountain silver mines of Germany from 1834 to 1854, were not very complicated inventions. These handmade ropes, known as Albert Ropes (after William Albert, the Harz mining official who pioneered the practice) were not very flexible because the wires were relatively large and stiff. Meanwhile, at the same time the Germans were achieving wire rope success in the Harz mines, a London inventor named Andrew Smith was experimenting with various ways to apply wire ropes to ship's rigging. In the meantime, another Englishman, Robert Newall, learned about the Albert ropes. Smith soon left England for California and the Gold Rush.
The Factory Floor, Part 1 of 4:The Quotation (or, How to Make a BOM) This month, I will be teaching a few MIT Media Lab graduate students and doing a bit of a “geek tour” of Shenzhen – we will visit several factories and live among the electronic markets to facilitate new directions and expand horizons in the students’ hardware-oriented research projects. As part of the course, they will learn how to scale up their research utilizing the China manufacturing ecosystem. These lessons may also be useful for Makers looking to bootstrap a product in moderate volumes (hundreds to thousands of units). I will share some tips and insights from the course in four posts over the next month covering: Getting a quotation: documentation standards (how to make a BOM) Process optimization: design for manufacturing and test jigs Industrial design for startups: guerrilla engineering on a shoestring budget How to pick a factory: building and maintaining partnerships Part 1 of 4: The Quotation (or, How to Make a BOM) Let’s consider a simple case study. Approved manufacturers
Interchangeable parts Ford assembly line, 1913. The magneto was the first to be assembled. The concept of interchangeability was crucial to the introduction of the assembly line at the beginning of the 20th century, and has become an important element of some modern manufacturing but is missing from other important industries. Methods for industrial production of interchangeable parts in the United States were first developed in the nineteenth century. The term American system of manufacturing was sometimes applied to them at the time, in distinction from earlier methods. First Use[edit] Evidence of the use of interchangeable parts can be traced back over two thousand years to Carthage in the First Punic War. In East Asia during the Warring States period and later the Qin Dynasty, bronze crossbow triggers and locking mechanisms were mass-produced and made to be interchangeable. Before the 18th century, devices such as guns were made one at a time by gunsmiths, and each gun was unique. Implementation[edit]
Involute gear Gear with teeth whose profile is an involute of a circle The involute gear profile is the most commonly used system for gearing today, with cycloid gearing still used for some specialties such as clocks. In an involute gear, the profiles of the teeth are involutes of a circle. The involute of a circle is the spiraling curve traced by the end of an imaginary taut string unwinding itself from that stationary circle called the base circle, or (equivalently) a triangle wave projected on the circumference of a circle. Advantages and design[edit] The involute gear profile, sometimes credited to Leonhard Euler,[1] was a fundamental advance in machine design, since unlike with other gear systems, the tooth profile of an involute gear depends only on the number of teeth on the gear, pressure angle, and pitch. In involute gear design, contact between a pair of gear teeth occurs at a single instantaneous point (see figure at right) where two involutes of the same spiral hand meet. References[edit]
Sisällysluettelo - Komposiittirakenteet Metal casting Pouring liquid metal into a mold Casting processes have been known for thousands of years, and have been widely used for sculpture (especially in bronze), jewelry in precious metals, and weapons and tools. Highly engineered castings are found in 90 percent of durable goods, including cars, trucks, aerospace, trains, mining and construction equipment, oil wells, appliances, pipes, hydrants, wind turbines, nuclear plants, medical devices, defense products, toys, and more.[2] The modern casting process is subdivided into two main categories: expendable and non-expendable casting. Expendable mold casting [edit] Expendable mold casting is a generic classification that includes sand, plastic, shell, plaster, and investment (lost-wax technique) moldings. Sand casting is one of the most popular and simplest types of casting, and has been used for centuries. Loam molding has been used to produce large symmetrical objects such as cannon and church bells. Plaster mold casting Waste molding of plaster
Yleistä Lean Six Sigmasta - SixSigma Lean Six Sigma on parannusmenetelmä. Sitä käytetään ensi sijassa työsuoritusten, prosessien ja systeemien suorituskyvyn (capability) parantamiseen. Suorituskyky on parasta, mitä kulloinkin systeemillä/prosessilla on saavutettu kokonaisuutena, ei vain maksimina tai miniminä. Se ei myöskään ole vain virheitä, vikoja tai reklamaatioita vaan kattaa kokonaisuuden. Suorituskykyä mitataan erityisillä suorituskykymittareilla/indekseillä (Cp, Cpk). Menetelmä soveltuu kaikkiin työsuorituksiin, prosesseihin ja systeemeihin toimialasta riippumatta. Lean Six Sigma menetelmä, jolla parannuksen aikaansaava tekijä/asia löydetään, muodostuu analyyttisten työkalujen ja analyysien joukosta. Suuri osa (> 95%) organisaatioiden ongelmista, virheistä, kustannuksista on systeemin tai yksitäisten prosessien suorituskyvyn heikkoutta. Huonon suorituskyvyn omaavissa prosesseissa syntyy palveluja, tuotteita, jotka eivät ole hyviä. Lean Six Sigma -menetelmässä yhdistyy aika- ja vaihtelulähestyminen.