Jump to content

Rocket Man

Members
  • Posts

    38
  • Joined

  • Last visited

Everything posted by Rocket Man

  1. cough..splutter..gasp... been down with the flu' and I'm now away overseas for a week. Couldn't get the full set of drawings for the WTF Powermeter released before I left but here's an appetite wetter. I'll post detailed drawings when I get back.
  2. You guys are just not trying... Take all the c&@p off it and turn it into a track bike. Then you'll see why track racing is sooooo much fun!
  3. ...I know, I know...I even beat him once.
  4. Excellent stuff Gary. I will be there for the whole league. ...even though I know I'll get mashed by the Elites (Cat4) but thrown out of Cat2... Anyone got any "get younger" pills?
  5. as a believer in high intensity training I use the IDT, rollers and track on the weekends. Continued my experiments into "marginally legal performance enhancing drugs" last night. Used Peroni. Tastes great but has too many bubbles during the sprints. Had to "flatten" it by adding Archers Peach Schnapps. Worked much better after that I think.... actually I forgot to turn the recorders on so I'll have to repeat the experiment tonight....
  6. Hence my road fixing comment... 100% agreement. That's what I'm looking for here - how far can organisers go to ensure a FUNTASTIC event? No holds barred, no limits, no excuses...
  7. Whilst some of these things are the responsibility of other organisations or just nice-to-have's, the riders want them sorted out so that they can have an exciting race that runs smoothly right from first idea to bragging to your friends that you're on TV. As an organiser you can't blame someone else when things go wrong. The rider has paid the money and wants good service!
  8. Here are the main points: Track/road maintenance System for collecting entry fees Rights of use for track events Lack of transparency in use of funds/sponsorships Entry table on race day Advertising boards at track events Insufficient bike checks on race day Maintenance of ?free? bikes at tracks Officials ? starter on race days Officials ? score keeper on race days Officials ? line judges Lack of photography on race days Lack of videos on race days Poor or non existent race results and reports Website design and maintenance (CGC, CSA etc) Poor information about top racers Poor relations with CSA Limited contact with schools Prize money Insufficient notice of upcoming events Inaccurate race calendar Medical support at race events Officials responsible for rules, regulations and protests Posting of event notices on other websites Publishing of results on other websites Publishing of results in printed media Poor TV coverage of track events Drug testing and control ? hard to get updated drug manual Technical support at race and training events Management of safe cycling centers Safety equipment and clothing for track racing Management of the warm up area at race events Mixing of age/sex categories Management of numbers for race events Coordination of inter-provincial events Coordination of national championships Spectator control at race events Announcer at race events Music at race events Maintaining league results Organizing lights at race events Managing and handing out prizes at race events Posting of race results on race day Maintaining of notice boards at tracks Indemnity forms Maintenance of track and provincial records
  9. Whilst I'm waiting for the first parts for the WhatTF powermeter I'm helping to organise some cycling "events". At the risk of being boring and repetitve can hubbers please help us make sure that the mistakes of the past are not repeated. I have a list of 75 complaints about cycling in SA that I have collected from this forum. These form the basis of a "what-not-to-do-list." But I want to make sure that we have every base covered so that these events are absolutely the best that they can be. So... WHAT DON'T YOU LIKE ABOUT CYCLING EVENTS ORGANISED HERE IN SA?
  10. A typical design becomes fraught with peril when trying to use strain guages. They tend to measure the very things that you don't want to measure, like temperature and lateral loads. Whilst purists will scream that you can't allow the chain ring to move with respect to the spider I think that the way to get a useful signal out of a mechanical device is to allow some significant and measurable motion - much larger than the effects of temperature expansion. I'm thinking of a rotation that equates to 1mm/kW at the circumference. Using this relatively large motion we need to measure a movement of about 0.01mm in order to achieve 1% resolution. Using interfering magnetic discs we could have magnetic domain sizes of the order of 0.1mm and easily reach this value. What makes the proposed design insensitive to the usual mechanical tolerances is that the magentic tracks will be balanced - ie there will be two sets of tracks generating interference patterns that move in opposite directions. It is only the relative movement of these patterns that needs to be detected. Also, the interference mixing takes place magnetically before the pickup so there is no need to use high speed, low sensitivity pickups. Instead, simple hall effect devices will detect the two slow beat patterns and measure their relative phase difference. The electronics part of the design is almost trivial. This is a mechanical gizmo...
  11. I get the feeling that the existing products have many engineering compromises in them, such as non-linearities in the strain response of the mechanical parts. What we should aim for is a simple construction that has as few parts as possible using materials that have almost ideal characteristics. Whilst I personally love the idea of something that has "that composite look" it would probably be better to keep that for cosmetics rather than function. I'm putting together concept drawings of the mechanical parts. The aim is to resricting all "movements" to a single degree of freedom - in this case a simple rotation. There has to be minimum error at the zero load end and absolute linearity along the scale. The complication is that the "pull" of the chain is radial on the chain ring, not axial. This means that there are forces trying to both "twist" and "pull backwards" on the spider at the same time. Not an easy thing to measure. I would rather "get rid of" the pull and deal only with the twist. As a design philosophy we should aim to avoid the modern trend towards trying to "fix" fundamental design flaws in software. If the basic transducer is stable and linear then life becomes real easy...
  12. Something fun for a Friday. Print the picture below. Cut the page in half between the two sets of railway lines. Turn one page over over and line up the images so that they are on top of each other (printed sides together). Hold the pages up to the light. If you look closely you will see a darker area and a lighter area because of the way the sleepers line up. If you slide one page over the other by a few millimeters then the dark and light areas move but over a much bigger distance (in the direction of the railway lines) . What this shows is that a small movement (such as a bend caused by pedaling hard) can be magnified into a very large effect by looking at the "interference pattern" created by stripes if they are laid out in a certain pattern. This is how we will measure the torque that is converted into a power reading. But instead of optical stripes, we will superimpose magnetic domains encoded onto a plastic disc coated with ferric oxide.
  13. Marius, I think you've got it! How about: The WTF power meter?
  14. Thanks to everyone who has contributed to this project so far. Once again TheHub shows its power by providing excellent cycling related information. In just over 24hrs the design of a "value for money" power meter has gone from a simple idea into the start of a real project. Contributions from the following people have been invaluable: Suggested name:<?: prefix = o ns = "urn:schemas-microsoft-com:office:office" /> cyclowatt - jeremyd Power Hubber - RM SpiderHub- Shade PowerRoc ... from RocMan - DaHawk Suggested price: R3k ? shade R599.95 ? bob the builder R500 ? Pro-Funrider R3k ? The <?: prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /> Hawk CT Interest from: BikeMax Odion Onetime jeremyd Le Tour PEEZ@ Testing: bob the builder Lateral ideas: SwissVan 101% JasonW Market and competitor information: Christie word Graphic design: Mampara Technical input: Christie mrmed ? machining bruce Coffee and support: Slowbee Patent searches: Edman Should we take this design further?
  15. Easy gang. Let's just assume that money is no problem for now. I estimate that it would take between R200k and R500k to go into proper production so don't even worry about it. On the picture below the black area is where the power adaptor sits (but in between all the arms of the spider). The red arrow shows how you rotate the rings into the new hole positions.
  16. This thing does a direct power measurement so it's not necessary to take anything else into account. To which Q factor do you refer Bob? What about calling it "Power Hubber" after the input from this forum? Names so far: cyclowatt - jeremyd Power Hubber - RM
  17. done some more calculations It is possible to get the power meter (we need a name for this thing, ideas anyone?) to produce a "synthetic" output that does a linear conversion from power/10 to cadence - in other words, any standard cycle computer (cheap or expensive) that has a cadence input could read power but the reading would be ten times smaller than actual: 100W => 10rpm 1000W => 100rpm a possibility...
  18. The Aruba thing is just wishful thinking. I live in Jhb. The display part of the powermeter is not that expensive as long as functions are limited to power specific readings - maybe a few R100 material cost. So I don't think it's necessary to compromise on the readout by trying to hook up with an existing device. I was thinking of getting the mechanical parts cast in a stainless material with the right mechanical properties - can use lost wax process for small production run, high precision but inexpensive tooling. ps Bob your box is fullRocket Man2008-04-24 04:14:36
  19. For the non-believers out there I'll tell you how it works - I believe in open source! There are two elements to a power meter - the power sensor and the display. The hard part is the power sensor. The display is more about graphic design than cutting edge technology. The power sensor itself has two critical components: 1. A mechanical device that bends or distorts when loaded. 2. A measuring device that determines how much bending has taken place. For the first component, the SRM uses metal beams that bend when you push on the cranks. This bending is measured by strain guages glued onto the beams. In the proposed design the mechanical system will also use bending beams but engineered in a rather unusual configuration so that it fits onto a standard spider. The measuring device that detects the bending of the beams will use technology derived from the magnetic media used to store data on a hard drive. Simply put, as the beam bends two magnetic pickups will read different data streams coming from two circular "tracks" attached to the bending parts. For those with some electronics knowledge, the "beat pattern" from the data stream changes phase as load is applied. Simple ne?
  20. Nice spider from quarq but it's outside the price range that I had in mind. The strain guage technology that they use is expensive and difficult to manufacture reliably. I want to use a totally different measuring principle.
  21. What I actually need to start the project is: 1. Enthusiasm - my job is developing new products and I want to try something cycling related (but it's very hard work). 2. An idea of how many could be sold and at what price. I don't care if it's two or two thousand pieces but I'm not going to make just one for myself. 3. Input from interested cyclists and trainers - that's why I'm talking to you hubbers. The biggest mistake that designers make is building something that they want to build rather than talking to the people who know what is really needed. I need as much input as possible from as many people as possible - not just cyclists but everything from machinists to graphic designers to software developers to sales people. If we can get the right resources together we may be able to make a useful device. But I have no illusions about making any money from it.
  22. Got an IDEA for a low cost power meter that fits onto standard cranks between the spider and the chain rings. Basically you take the rings off, bolt the "power disc" onto the spider then put the rings back on but rotated slightly. Easy to install and swop between bikes. Will work on road and track bikes and has an accuracy of better than 1%. There are no batteries in the power part - only the display. Doesn't require recalibrating. It normally displays the power but it can also download a detailed profile of your pedaling stroke. It doesn't need any fancy software to view the data - it produces a text file that will import into Excel to let you keep records and draw whatever graphs you want. Is anyone interested? How much would you be willing to pay for something like this?
Settings My Forum Content My Followed Content Forum Settings Ad Messages My Ads My Favourites My Saved Alerts My Pay Deals Help Logout