As a freelancing draughtsperson, I have received widespread experience for my contributions in both mechanical and electrical draughting while being involved in product development, presentation, and design reviews. My work involved a combination of technical expertise and creativity. I also brings together technologies from different environments and works inventively. In so doing, I am able to translate ideas into working products that meet the needs. I also endeavour to help engineering designers in improving their productivity. My primary function was to identify the specific needs of professionals designers within the construction industry and then to meet these requirements in a professional, time sensitive and cost-effective manner. I also offer services as complex as Concept Design, Project Planning and Compiling Design Applications or Presentations. I work with a team of skilled and experienced draughtsman from different disciplines who are dedicated to providing reliable and professional service that is on time every time. We use the latest Synchronous 3D modelling software and also use laser as well as infrared reflector-less surveying equipment onsite when producing layout drawings, assembly or detail drawings and mechanical surveying depending on the clients requirements.

Saturday, August 27, 2016

Types of Draughting Services

Technical drawing is essential for communicating ideas in industry and engineering. It also is a legal document (that is, a legal instrument), because it communicates all the needed information about "what is wanted" to the people who will expend resources turning the idea into a reality. It is thus a part of a contract; the purchase order and the drawing together, as well as any ancillary documents (engineering change orders [ECOs], called-out specs), constitute the contract. Thus, if the resulting product is wrong, the worker or manufacturer are protected from liability as long as they have faithfully executed the instructions conveyed by the drawing. If those instructions were wrong, it is the fault of the engineer. Because manufacturing and construction are typically very expensive processes (involving large amounts of capital and payroll), the question of liability for errors has great legal implications as each party tries to blame the other and assign the wasted cost to the other's responsibility. This is the biggest reason why the conventions of engineering drawing have evolved over the decades toward a very precise, unambiguous state. For centuries, until the post-World War II era, all engineering drawing was done manually by using pencil and pen on paper or other substrate (e.g., vellum, mylar). Since the advent of computer-aided design (CAD), engineering drawing has been done more and more in the electronic medium with each passing decade. Today most engineering drawing is done with CAD, but pencil and paper have not disappeared. Some of the tools of manual drafting include pencils, pens and their ink, straightedges, T-squares, French curves, triangles, rulers, protractors, dividers, compasses, scales, erasers, and tacks or push pins. (Slide rules used to number among the supplies, too, but nowadays even manual drafting, when it occurs, benefits from a pocket calculator or its onscreen equivalent.) And of course the tools also include drawing boards (drafting boards) or tables.

A structural drawing, a type of Engineering drawing, is a plan or set of plans for how a building or other structure will be built. Structural drawings are generally prepared by registered professional structural engineers, and informed by architectural drawings. They are primarily concerned with the load-carrying members of a structure. They outline the size and types of materials to be used, as well as the general demands for connections. They do not address architectural details like surface finishes, partition walls, or mechanical systems. The structural drawings communicate the design of the building's structure to the building authority to review. They are also become part of the contract documents which guide contractors in detailing, fabricating, and installing parts of the structure.

An architectural drawing is a technical drawing of a building (or building project) that falls within the definition of architecture. Architectural drawings are used by architects and others for a number of purposes: to develop a design idea into a coherent proposal, to communicate ideas and concepts, to convince clients of the merits of a design, to enable a building contractor to construct it, as a record of the completed work, and to make a record of a building that already exists. Architectural drawings are made according to a set of conventions, which include particular views (floor plan, section etc.), sheet sizes, units of measurement and scales, annotation and cross referencing. Conventionally, drawings were made in ink on paper or a similar material, and any copies required had to be laboriously made by hand. The twentieth century saw a shift to drawing on tracing paper, so that mechanical copies could be run off efficiently. The development of the computer had a major impact on the methods used to design and create technical drawings, making manual drawing almost obsolete, and opening up new possibilities of form using organic shapes and complex geometry. Today we create a vast majority of drawings using CAD software.

An electrical drawing, is a type of technical drawing that shows information about power, lighting, and communication for an engineering or architectural project. Any electrical working drawing consists of "lines, symbols, dimensions, and notations to accurately convey an engineering's design to the workers, who install the electrical system on the job". A complete set of working drawings for the average electrical system in large projects usually consists of: A plot plan showing the building's location and outside electrical wiring; Floor plans showing the location of electrical systems on every floor; Power-riser diagrams showing panel boards; Control wiring diagrams; Schedules and other information in combination with construction drawings.

A plumbing drawing, a type of technical drawing, shows the system of piping for fresh water going into the building and waste going out, both solid and liquid. Within industry, piping is a system of pipes used to convey fluids (liquids and gases) from one location to another. The engineering discipline of piping design studies the efficient transport of fluid. Plumbing is a piping system with which most people are familiar, as it constitutes the form of fluid transportation that is used to provide potable water and fuels to their homes and businesses. Plumbing pipes also remove waste in the form of sewage, and allow venting of sewage gases to the outdoors. Fire sprinkler systems also use piping, and may transport nonpotable or potable water, or other fire-suppression fluids.

A Mechanical systems drawing is a type of technical drawing that shows information about heating, ventilating, and air conditioning. It is a powerful tool that helps analyze complex systems. These drawings are often a set of detailed drawings used for construction projects; it is a requirement for all HVAC work. They are based on the floor and reflected ceiling plans of the architect. After the mechanical drawings are complete, they become part of the construction drawings, which is then used to apply for a building permit. They are also used to determine the price of the project. Arrangement drawings include information about the self-contained units that make up the system: table of parts, fabrication and detail drawing, overall dimension, weight/mass, lifting points, and information needed to construct, test, lift, transport, and install the equipment. These drawings should show at least three different orthographic views and clear details of all the components and how they are assembled. The assembly drawing typically includes three orthographic views of the system: overall dimensions, weight and mass, identification of all the components, quantities of material, supply details, list of reference drawings, and notes. Assembly drawings detail how certain component parts are assembled. An assembly drawing shows which order the product is put together, showing all the parts as if they were stretched out. This will help a welder to understand how the product will go together so he get an idea of where the weld is needed. The assembly drawing will contain the following; information overall dimensions, weight and mass, identification of all the components, quantities of material, supply details, list of reference drawings, and notes. In detail drawings, components used to build the mechanical system are described in some detail to show that the designer's specifications are met: relevant codes, standards, geometry, weight, mass, material, heat treatment requirements, surface texture, size tolerances, and geometric tolerances. A fabricationdrawing is made up of many different parts and has a list of parts that make up the fabrication. In the list, parts are identified (balloons and leader lines) and complex details are included: welding details, material standards, codes, and tolerances, and details about heat/stress treatments.

Friday, August 26, 2016

Power Plant | Engineering

Some dc motors can be used as generators as well by applying mechanical torque to the output shaft to induce a current. However, even if a dc motor can do this, I imagine they were not designed for this purpose and thus perform less efficiently when used as a generator rather than as a motor. In my admittedly naive understanding, dc generators and dc motors are essentially the same machinery, but with inputs and outputs reversed. This leads me to believe that some other design considerations are used to make one direction more efficient than the other. How differently are DC generators and DC motors designed to make one direction of input/output more efficient than the other? What can I do electrically or mechanically to improve the efficiency in either direction? In particular, I'm interested in converting a DC motor into a generator and want to know how I can improve its efficiency in converting mechanical energy into electrical energy.

DC generators began as brushed commutated devices. They had a one or more stator windings and an armature winding. Field wound DC generators as well as motors were commonly connected in one of three methods: Series, Shunt and Compound. Without getting into details, each had its own set of strengths and weaknesses. But you only have to remember these two things: the voltage of a DC motor is dependent on its input shaft speed. Current is a function of torque. More voltage means more RPM's and more amps means more newton-meters....

So with all that, I need a constant speed source to get a constant voltage. And I need to ensure I have enough torque to satisfy the current demand of the load otherwise voltage drops off. Old vehicle had commutated generators. They couldn't regulate the voltage so they used a range of around 10-14 volts and used a relay that simply closed when the engines speed was within the voltage range. If the voltage went too low or too high, the relay opened. Primitive by today's standards. The Alternator in today's vehicles uses a voltage regulation circuit that varies the armature current which changes the field strength based on the stators output voltage. Lower speed means more current to the armature and less current at higher speeds.

So how different were DC generators from motors? Not very different at all. If anything they mostly differed in mechanical design as they were to be coupled to a prime mover (steam, ICE, electric etc.). Well, firstly the dynamos do need either some kick-start power or permanent magnets, as they can't depend on electromagnets in the stator only; I know that I won't generate any electricity by moving a wire without any current next to another wire without any current. A permanent magnet DC motor will act as a dynamo if I provide rotation power to its axis, so there's not much difference here. The commutator may be aligned a little bit differently, ignoring the need to cut off early, when the magnetic field would brake the motor; there would be no concern about not creating a 'dead zone' where the motor wouldn't start, not pulled by a neighbour magnet. If anything, the device would be considerably simpler. Now if I want to engage electromagnets for the stator, there will be some differences... usually they would be powered from an external source, which could be then charged from the dynamo.


Though, in much larger dynamos they had adjustable commutator brushes to compensate for the shift in the commutation plane as a result of heavy load characteristics. A hand wheel would turn a worm gear which would advance or retard the commutation plane to bring the generator back into its normal operating parameters. I'm guessing that it's the nameplate RPM which I need to spin the motor at to get the nameplate voltage. This means if I have a 12V motor that spins at 6000 RPM, I'll need 6000 RPM to get 12V. If I don't have a constant speed source then I have no way to regulate the voltage. I would then need a buck-boost switching regulator to get a constant voltage from the motor.

DC generators, or dynamos of any significant size are rather rare these days. It's much more common to use an AC generator (alternator) with an external rectifier. And just for reference, an AC motor can also generate power if you spin it faster than its nameplate RPM, usually at synchronous speed. But again, no voltage regulation and a constant speed is needed. More trouble than its worth. Also of note: jet planes use a very elaborate mechanical speed regulator to produce constant shaft speeds which ensures a constant 60 or 400Hz AC frequency as the throttle is varied.

Thursday, August 25, 2016

Technical Illustration | Design

Technical illustration is a broad field of study. It covers any illustration assignment that needs to show the viewer how something functions or how parts are interrelated. At its heart is clarity and precision, and consequently it requires more discipline and knowledge. I believe illustrators need to work longer and harder to gain the skills needed. New illustrators and students need to know it’s going to take passion and dedication to be successful in this field. Technical illustrators need to be able to draw well. This means being able to accurately depict the world around us with line, tone and color. Don’t expect to gain this by attending a few classes in school, it will take a lifetime of learning, and continued practice to maintain. Students need to study perspective, how to render light and shade as well as color theory. Don’t expect computer programs to do this for you. If you wish to include the figure in your work you will need to study artistic anatomy as well.

I love illustration as much or if not more than editorial design. I also use my engineering draughting background which is still part of what I do. When I began exploring technical illustration, the tools of he trade were roting pens, drawing boards, etc but I caught the wave of desktop publishing just at the right time. Photography can be expensive with illustration you can build a world that is immersive at a fraction of the cost. Working as a technical illustrator is not a passive act, you are expected to research and understand the topics you are given. In addition you will need to solve the many technical and design issues that arise with each assignment. The artistic quality of your work is up to you. Hopefully you have a passion for fine art and can bring flair to your work that is attractive. I believe that technical illustration should be beautiful as well as useful because the future of publishing is digital.....

Saturday, August 20, 2016

Vehicle Manufacturing | Entrepreneur

 The Automotive Manufacturing Industry Certificate (AMIC) has been the benchmark for vehicle manufacturers in South Africa for many years, but this certificate has not been aligned to unit standards. This has meant that learners who have gone through the learning process have achieved valuable skills, but have not received any form of recognition for these skills. Various interventions have been entered into over the years to try and align the AMIC programme with SAQA unit standards and qualifications, but it was found that the AMIC programme was more complex than a SAQA qualification and covered various unrelated areas. This difficulty has been addressed by focusing achievement of this qualification on the essential elements of vehicle manufacturing and allowing manufacturers to choose additional existing courses for their learners in more generic areas such as logistics, administration, quality assurance and technical non-production. This means that a qualification can now be developed to give recognition for all people who work in a vehicle manufacturing plant in any of the areas identified as a specialisation for this qualification.
This qualification has been designed to specifically cater for the unique needs of the South African vehicle manufacturers and is at a level below that which most other countries provide training at. The countries looked at for international comparability include Japan, Germany, Thailand, England, Spain, Mexico, Turkey, United States of America and Brazil.

South Africa has adopted a much more labour intensive approach to manufacturing vehicles in order to provide jobs and meet economic requirements. Each of the above countries use skilled artisans to manufacture vehicles, and focus on advanced technology and robotics more than the South African manufacturers. These countries also only employ qualified people in the manufacturing plant, whereas South Africa employs unskilled labour that can be trained to this qualification in a manner that integrates learning and work. Where additional training is required in the other countries, training is conducted off the production line, whereas the training in South Africa is conducted in the plant.

Elements of the Institute of Motor Industry (IMI) in the UK have been used in benchmarking best practice procedures in some of the unit standards used in this qualification. The NVQ qualifications offered in the UK cover all the same objectives of this qualification but at a higher level of complexity. The qualifications are offered as an internship wherein the learner enrols with a college or training centre for the theoretical component, and achieves the practical component in-house. The qualifications are all based on specific levels of performance, and lead to progressive levels of complexity, but are identified as separate qualifications.The qualifications offered in Germany are also vocational qualifications with theoretical components being achieved through a specified period at a training centre. The qualifications are aimed at achieving complete competence in all aspects of vehicle manufacturing through a progressive series of qualifications and includes mechanical, electrical and coach works. The training programmes are progressive qualifications of one-year duration each and include ongoing training through workbooks in which the trainee is required to complete evidence of understanding for each month of the registered year of learning. Germany has a requirement that competent people be licensed to operate under the meister (master craftsman) programme, and this licence is valid for a period of two years.

 America uses a system of specialisation areas, with a master technician being identified as a person who is competent in all areas and will be able to assemble any part of a vehicle. The learning is conducted through apprenticeships and has specialisation areas for engine technicians, transmission technicians, steering and suspension technicians, brake technicians, electrical system technicians, heating and air-conditioning technicians, driveability and performance technicians and lubrication technicians.

Other African countries do not have full manufacturing plants, but import semi knocked down units that are then assembled by trained operators without a formal qualification. It is anticipated that this qualification will have a strong appeal within the African market and will provide qualifications for people that would otherwise be unrecognised for their skills and knowledge.

Registration as vehicle manufacturer or importer
Should you want to manufacture, import or build motor vehicles in South Africa for profit, you must first register with the provincial department of transport. Once the department receives your application, it will send an inspector to determine if you comply with the relevant regulations. Your business will also be subjected to South African Police Service (SAPS) clearance.
What you should do
  1. Go to the provincial department of transport and submit the following:
    • a completed application and notice in respect of manufacturer/importer/ builder of vehicles (MIB) form
    • certified copy of the applicant’s identity document (ID)
    • certified copy of the proxy’s ID (if the applicant is a body of persons)
    • certified copy of the business certificate (if the applicant is a body of persons)
    • letter of proxy if you represent a company 
    • custom code number from the South African Revenue Service (SARS) (if you are an importer)
    • proof of VAT registration from SARS
How long does it take
Registration is subject to the relevant MEC’s approval and the registration certificate is issued on such approval.
How much does it cost
Contact your local department of transport for the cost.
Forms to complete
Application and notice in respect of manufacturer/importer/builder of vehicles (MIB) form. Forms are obtainable at the registering authority or you can download them from the eNaTIS website.

NAAMSA - The National Association of Automobile Manufacturers of South Africa - is an  important source of information about the motor industry in sub-Saharan Africa. After 50 years of being the official body representing new vehicle manufacturers, it is now going through major changes in line with the transformation of the industry. The NAAMSA membership base now includes major importers and distributors of new vehicles as well as local manufacturers and assemblers, making it the pre-eminent organisation for all franchise holders marketing vehicles in South Africa.

Every month, NAAMSA makes the headlines with its release of the latest new vehicle sales figures, which have become recognised as significant barometers of the country's economic activity, consumer trends and general fiscal health. The compilation of these sales statistics is a sophisticated operation on a par with similar motor industry marketing information gathering in the industrialised nations of Europe and North America. The figures are far more detailed than the summaries carried in the general media suggest and you can find an in-depth analysis and graphs in our web pages or contact NAAMSA directly at the address below - which should, in any case, be your first call if you are new to the South African market and serious about doing business in the motor industry here.

There is a NAAMSA working group or specialist committee tackling each of the major issues facing the industry - ranging from local content to vehicle crime and safety legislation. A sign of the times is the new NAAMSA Export Division as the industry reaches for overseas markets, and a whole range of activities linked to the Motor Industry Development Programmes.

Aviation Legalities | Transportation

South African air law revolves around the expressions "authority to fly " or " permission to fly".
The Air Navigation Regulations from 1976 state in 1.10 (1) No aircraft shall be flown in the Republic unless - ... Means , by default flying is verboten. No person and no man made object is allowed to fly in South Africa. Unless you get permission to fly from the government. The South African government is the landowner of the air around us. Besides getting permission from the landowner for a flying site to use a takeoff and landing area, we also need permission from the government , if we want to fly.  For the South African government the  Department of Transport is in charge of the airspace in South Africa. Who delegated  the management of the sky in South Africa to the CAA, the Civil Aviation Authority. And along with that delegation a new buzz word got created , the "user pay basis", which got introduced in the 1990's..

Out went the  idea of "free flying", but we still got the "free dying", as far as I know. Have not met anyone who came back from the pearly gates complaining that they charge an entrance fee. The CAA delegated the administration for Hang Gliders and Paragliders in 1991 to AeCSA, the Aero Club of South Africa, a Section 21 company. This delegation is at the moment based on a Memorandum of Understanding  which gets renewed now and then. Or not. CAA can take it back whenever they feel like it.

CAA has produced , and carry on producing,  piles of paper with rules and regulations called Civil Aviation Rules  (CARS). They are on the web at  follow the CARS  or the  CATS   and the Non Type Certified Aircraft  link. Some of them have been  gazetted, some will be gazetted, and some have been put on ice. And some wait for translation into the 2nd official language, what is Zulu.  See AIC 18·23 . Those which have been gazetted can be considered as a law. And if you do not adhere to a law then you can end up with a criminal court case. For me it is not quite clear what got gazetted and what not. Some of those CARS off the CAA website say "Effective from whatever date"  and then I get told that they are not! And some of what got gazetted is not realistic when it comes to our type of flying.

The CARS that are relevant for Hang Gliding and Paragliding are:
  • Part 1 has definitions like what is considered an Accident, Incident, Hazard, or what is Daylight, ... and what the abbreviations like VFR or MSL mean
  • Part 12 defines what has to be reported and by whom, and to where. Like when we got a dead body,  notify the police. And it says there that accidents, incidents and hazards have to be reported.
    • For example 12.02.5 Notification of hazards
(1) Any person involved in an accident or incident, or observing any accident, incident, hazard or discrepancy that may affect aviation safety, may notify the designated body or institution referred in regulation 12.01.2, of such accident, incident, hazard or discrepancy. (
2) Any person who notifies the designated body or institution referred to in regulation 12.01.2 of an accident or incident, shall not be absolved from the duty to notify the Commissioner of such accident or incident in terms of regulation 12.02.1, 12.02.2 or 12.02.3, as the case may be.
  • Part 24  defines our flying machines as non type certified aircraft and that it has to be airworthy to fly.
    •  The airworthiness of the aircraft, classified in sub-groups (h) to (l) in sub-regulation 24.01.1(2), shall be the sole responsibility of the owner or operator in accordance with generally accepted practices for such aircraft or as laid down by the organisation, approved for the purpose in terms of Part 49.
    • Part 24.04.3   defines who can test ...  APPROVED ORGANISATIONS

      1.             Test authorities approved for the certification of hang-gliders, paragliders and parachutes
                     The following test authorities have been approved by the Commissioner or the organisation designated for the purpose in terms of Part 149, as the case may be, for the certification of hang-gliders, paragliders and parachutes:
      *               AFNOR (The French ACPULS certification)
      *               AHGF (The Australian Hang Gliding Federation)
      *               BCAR (British Civil Aviation Regulations)
      *               DHV (The German GUTE SIEGEL certification)
      *               DULV (Deutsche Ultraliecht Verein)
      *               HMA (US Hang-gliding Manufacturers Association)
      *               SAPA (The South African Parachute Association reserve parachute testing procedure
      *               SHV (The Swiss Hang Verein certification
      *               USHGA (The United States Hang Gliding Association
      At the moment it is not clear to me if SAHPA or Aero Club is approved as an organization in terms of Part 149.
      • The SAHPA Operations and Procedure Manual states that all new hang gliders and paragliders sold in South Africa shall have been certified by an approved test Authority and carry a label with the

      manufacturers name, a serial number, date of manufacture, quality
      controller's signature, pilot mass range and the class rating, and shall be
      classified in the Glider Classification Schedule.
      This regulation does not ask for DHV or Afnor stickers as such, but that the
      glider must have been certified and that all the information of the glider
      must be available on the glider. The information must include the DHV or
      Afnor rating, or any other test rating that SAHPA has deemed acceptable.
      • It also requires that all gliders that arrives in the country must be

      submitted for classification on the Glider Classification Schedule.
      • states that students have to be on a communication system when trained, in our case radios
    •  Part 61 and 62 covers licenses
Part 61 for example states.... Privileges of a paraglider pilot licence
(1) The holder of a paraglider pilot licence shall be entitled to act, but not for remuneration, as pilot-in-command of any paraglider engaged in a nonrevenue flight, for which the holder is type rated, in VMC by day.... But according to AeCSA in 2004 Part 61 is not  applicable for us. Confusing?
Part 62 handles licence requirements. Zipped files  or  MS Word Draft originals for Part 62 and Technical Specs.
What you have to do to be allowed to fly.... see also Proposed National Pilot's License - Part 62 (May 04) In August 2006 Part 62 got "finalized" See PART 62 August 2006  for details.
  •  Defines things like the amount of flights for a new  license and renewals
  • This will replace some of the Section 3 and 4 of the SAHPA Operations and Procedure Manual. The SAHPA committee will not any longer change license requirements on an ad hoc basis. If SAHPA decides to change, one will have to motivate it and get it approved by a CARCOM meeting by CAA. And then it has to get into the law making cycle and get gazetted. Means, whatever will be in this Part 62 we will have to live with for quite a while.
  •  Part 62 and Part 24 allow the ARO  (SAHPA) to define some more requirements for pilots and flying equipment. Like that one can only fly a certain glider with a certain experience level is defined in the Glider Classification schedule.
  •  Part 91 are the flight rules of the air for everybody , like
    • right is right
    • landing aircraft got right of way
  •  Part 94 states for example that we
    • have to fly in VFR conditions, not at night , not go into cloud,  and only fly in uncontrolled airspace
    • are allowed  to ridge soar
    • have to wear a helmet
    • have to get landowner permission to fly from a site
    • use for tandem and training only  approved sites which are on the SAHPA site register
    • operate a winch only with a guillotine or hook knife
    • need a  tandem rating to fly a passenger, maximum 2 people on a tandem, and a tandem needs a reserve
  • Part 96 mentions Tandem for reward
    •  For the purpose of sub-regulation (2), tandem operations with hang-gliders, paragliders or parachutes, even if carried out for remuneration or reward, shall not considered to be the providing of an air service as defined in the Air Services Licensing Act of 1990 (Act 115/1990) or International Air Services Act of 1993 (Act 60/1993) nor to be a commercial air transport operation, as defined in Part 1 of these Regulations.
  • Part 106 Operation of Hang Gliders and Paragliders. Repeats what is in the other Parts, like ...
    • you need a license , have to be a member of AeCSA and SAHPA
    • comply with the SAHPA Operations and Procedure Manual
    • have to wear a helmet and fly with a harness.
    • and stay out of clouds and not fly at night
    • fly Tandem and Instruct only from registered sites
But 106 is not active, see AIC18-4 which states  implementation of Parts 61, 66.09.1, 98, 100 through 106, 127, 133, 149 have been postponed in until further notice
  •   Part 185 says that you can get fined and get a prison sentence of up to 10 years for not adhering to any of the CAA regulations  by doing things like ....
    • falsifying your logbook,
    • cheating on your application forms,
    • or flying without a license,
    • or giving your glider to your buddy who is not licensed or has not got the correct rating ( 185.00.1.h .... permits a licence, rating, certificate, permit, approval, authorisation, exemption or other document issued under the Regulations, of which he, she or it is the holder, to be used, or a privilege granted thereby, to be exercised, by any other person;)

There is a draft on the CAA website to introduce in 2003 spot fines ranging from R1000 to  R75.000 for not adhering to any of the CAA regulations. Those spot fines can be imposed by CAA inspectors.  See also AIC 22.3

So, SA law says, if you want to take off into the air with a Hang Glider or Paraglider,  you need an Aero Club/SAHPA license. Also as a visitor, with a foreign license.  A foreign license does not entitle you to fly in South Africa. You first have to get a temporary SAHPA membership to fly legal in sunny South Africa. Not adhering to some gazetted law can give you a criminal court case. If it is a 100 percent clear cut case. And if things go wrong you can also get yourself into a civil court case, for not adhering to some CAA , SAHPA or local Club rule in some cases were someone is injured or some property is damaged. Where a judge can reckon that you are liable for a certain  percentage to whatever damage to the other party.

Thursday, August 18, 2016

Cycling ReDesigned | Engineering

Drift trikes are like three wheeled go karts with smooth rear wheels that allow the trike to slide sideways around corners. I tried drift triking out recently with some friends and one of them said “When you get it right you get up and go yeah physics!” So this made me decide to build my project while exploring the physics of drift triking and how to use it in drift trike design. I first discovered the world of drift trikes about 9 months ago and became instantly hooked and decided that I had to design and build one of these tricycles to have some fun on the tracks in the area where I live. I used to ride mountain bikes on these tracks but past injuries have left me unable to grind some of the tracks I used to, this is something I have missed over the last few years but now that I am working on my trike design I can once more enjoy the numerous tracks in my area.

The project is planed to start in September and it is was going to have a motorhead theme but finishing the project on schedule will be an added bonus. I have to procure all material and get ready for this project in a couple of months, I had planned this to be an over summer project and hopefully with no surprises. The trike will not see much action until next spring during testing were the days are longer, warmer and drier and I get the road safety side of things organized......This is only a general guide as to how i built my trike, I will not be responsible for anyone who decides to build a trike of their own, anyone building or riding a drift trike should take personal accountability for their own actions. Therefore anyone planning on building or riding a drift trike should be aware of the numerous dangers involved.

If you build a drift trike build it strong to minimize the risk of failures that result in injury. Drift trikes fall into the same category as bicycles and therefore require brakes and reflectors and also lights if you intend to ride at night. Personal safety equipment should also be worn by all riders,  most drift trike riders wear full face motorcycle helmets. In addition to a helmet knee and elbow pads are recommended along with gloves and wrist guard if you have them.
For the trikes most people start out with an off the shelf trike but it’s quite common for people to build their own or modify off the shelf ones. The following sections provide basic guidelines on what dimensions I will be using.

The front wheels are generally 20” (508mm) BMX wheels. The rear wheels are much smaller, around 200-220mm, and are either plastic wheels or go kart wheels with PVC pipe on the outside. The dimensions of the trike are important to get right to allow for the trike to slide and also be stable enough to not flip over constantly. Wheelbase Length = 970-1150mm  Track Width = < 1m  - Note: If the track is too wide it’s hard to drift however narrow ones are more unstable. Seat Position = 250-350mm forwards of the rear axle
Note: If the seat is too far back it’s easier to tip backwards and if it’s too far forward it’s harder to put the trike into a slide. One of the factors at play when going around a corner is inertia. Newton’s first law of motion, aka ‘Law of Inertia’, is:

An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

a = acceleration
t = track width
w = wheel base
l = longitudinal centre of gravity position
h = height of centre of gravity

Using the average recommended dimensions (t = 1m, w = 1106mm) and assuming a centre of gravity at height at 0.4m and longitudinal position 0.3m gives a roll over acceleration of 0.9g. The effect of inertia in cornering is that a vehicle and your body will keep trying to go forwards, to the outside of the turn. The frictional force on the wheels also acts at a distance from the centre of gravity so this creates a torque on the vehicle trying to tip it in the outwards direction. This results in more weight being transferred to the outside of the turn. This tipping force is balanced by the outer wheel normal force but there is a limit to the normal force. At high acceleration and friction force the inner wheel will stop supporting any weight and the outer wheel normal force can’t increase any more. If the frictional torque increases the normal force cannot provide enough resistance and at some point the trike will tip over. One of the ways that this is countered is by leaning inwards towards the turn. This shifts the centre of gravity so there is a greater moment arm acting from the outer wheel normal force to stop the trike from tipping.

Friction Force: F = μ N
N = Normal Force
μ = Coefficient of Friction

It’s also possible to calculate the minimum cornering acceleration that would cause the trike to tip. This can be found by doing static analysis of the forces and assuming that the inner rear wheel gives no support. Friction is another important part of vehicle dynamics. Friction force depends on the normal force (from the weight) and the coefficient of friction. When wheels are rolling smoothly, not slipping, the contact point on the wheel is stationary relative to the ground. This means that the friction force depends on the static friction coefficient. When the wheels start sliding the point of contact is in motion and the friction depends on the dynamic friction coefficient. The dynamic friction coefficient is generally less than the static friction coefficient so when the wheels are sliding the friction force is reduced. The rear wheels on drift trikes are designed to have reduced grip, either by being made of plastic or having PVC pipe covering the wheels. This allows the back wheels to slide easier.

Turning the front wheel creates a sideways frictional force that causes the vehicle to change direction. The frictional force from the front wheel is much higher than the rear so if you keep pointing the wheel in the direction of the corner this will resulting in the trike continuing to spin around, often tipping over in the process. Unless you’re trying to do a spin, the way you need to get around the corner is by pointing the front wheel in the opposite direction, e.g. turn left while you’re going right, also referred to as counter steering. This balances out the movement of the rear wheels and keeps the trike heading in the right direction......Drift triking is great fun and it’s interesting to find out more about the physics behind it as well.

Mamphake Mabule
c. 2016, Mabule Business Holdings

Design Layout | Architecture

A good design is one that fulfills all the functions you require of it, and at the same time is aesthetically pleasing. Once you have gathered ideas and established your priorities, you will need to decide on the layout, when coming to kitchen design, take into account the basic work triangle as well as traffic flow through the room. The key to any efficiently designed kitchen is its work triangle’, This is the logical inter-relationship of the cook’s three principal aids: the stove, the refrigerator and the sink, They should be sited so that you have access to each without having to take too many steps or circumvent obstacles in the process of fetching, preparing and cooking food, and of washing up, The three are positioned on the points of an imaginary triangle, which should be as compact as possible within the limits of free movement between the points. Having established your triangle, the related components will virtually position themselves: utensil and dry food storage areas will be close to the stove; crockery and cleaning material storage areas will be around the sink, and work surfaces will be close to both. The shapes seem to be of infinite variety to the casual eye, but in fact there are just four basic shapes: the single-wall, the galley (or corridor), the L-shaped and the U-shaped.

  The Single-Wall, or one-counter, is the only type of kitchen which cannot incorporate a work triangle. Preparing, cooking and washing up are all performed along one wall, which is an ideal arrangement for a small apartment, This is not its only application, however. You may indeed have plenty of available space but prefer to use most if it for, say, an open-plan configuration of cooking/eating or cooking/eating/sitting areas. The main drawback of this design is the difficulty in creating an efficient storage system. If the line is too short, you will not be able to squeeze in enough units and work surfaces. If it is too long, your work flow will be inefficient. The L-Shaped Kitchen is exactly what its name suggests. The triangle is not quite as efficient here, but this is probably the best shape if you want a completely integrated eating area or like the idea of having an island work station. An island work station can be anything from a simple table – providing an additional working surface – to a complex bank comprising a hob, sink and eating counter, and so by definition is suitable only for the medium-sized to larger kitchen.

The Galley or Corridor Kitchen – consisting of two parallel working areas – is an arrangement that allows for both a sensible work triangle and considerable flexibility when it comes to the room’s ancillary functions. You could, for example, make provision for an eating area beyond the work centre, or link the two by installing an eating counter between them. Lastly, The U-Shaped Kitchen, which has three working walls, is an excellent layout when space is at a premium. Here, the work triangle can be at its most compact with, again, the option of linking the eating area with the open end of the ‘U’.