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Geoff_H

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Everything posted by Geoff_H

  1. Geoff_H
    Very shortly I turn 75. NSW require that I get a medical from my GP. She is requiring that I also get an optometrist report at additional cost. I have a class 2 CASA medical certificate the DAME does my eyesight at no extra cost. As a car licence can be a medical for a RAA licence this question is probably a revelamt topic for this site. Anyone had to do the 75 medical?
  2. Geoff_H
    I like the dual cycle engines that are becoming popular in modern vehicles. The combustion starts as an Otto then converts to a diesel cycle (using petrol). These engines are more efficient than both diesel and Otto. When you see the temperature entropy and pressure enthalpy graphs this is shown. The best reason that I like them is that Mercedes is getting 400hp out of a 2 litre engine. I feel that a small engine with that output and efficiency could be the future for aircraft. My vehicle has a 2 litre 250hp engine and gets 6.4 litre/100km, very reliably, it has a dual cycle engine. It's manufacturer was talking about dropping the less efficient diesel engine in its favour. All seems to have changed now that the "climate change religion" reigns suprime.
  3. Geoff_H
    What is Warnervale like these days? Is it good for doing the biannual flight review for a private pilot licence?
  4. Geoff_H
    The speed of sound is a function of the density of the material it is being transmitted through.
  5. Geoff_H
    I am talking about the control systems inside the power systems not the 330kV or 500kV systems, they are very specialised systems. I was the commissioning engineer for the first Eraring 500kV switchgear. Another item that makes large spikes is the size of the wiring. The original power stations used 24/48V systems with 7/0.29 wire, modern systems use 1mm or less. Larger wiring gives larger spikes.
  6. Geoff_H
    I use autocad 3D for 3D printing. I have used acad since its inception in the 1980s ( or about then). I tried a free 3d cad package but it was too hard to learn at my age, something about old dogs and new tricks. 😁
  7. Geoff_H
    30 years ago I was writing acad program files (name eludese at the moment) I was able to take an excel file and extract data and create dwg files from the excel data. The formats for acad and SLC files is well documented. I expect that pdf file format is documented. I am 74 and too old to do it these days but you should be able to find a young budding programmer that would write such a program for you, maybe even for free. It appears that the software exists, for free some of them, do a PDF to DWG search on the internet. Feel free to contact me privately if you wish
  8. Geoff_H
    30 years ago I was writing acad program files (name eludese at the moment) I was able to take an excel file and extract data and create dwg files from the excel data. The formats for acad and SLC files is well documented. I expect that pdf file format is documented. I am 74 and too old to do it these days but you should be able to find a young budding programmer that would write such a program for you, maybe even for free.
  9. Geoff_H
    Is your a to make SLC files?
  10. Geoff_H
    Can I assume that you have pdf files and want them converted to DWG/dxf files?
  11. Geoff_H
    Sorry just realised it was 50 years ago I started work in Power Stations. I am getting old and forgetful.
  12. Geoff_H
    40 Years ago when I started working in power stations we used relays for control. We recorded spikes of nearly 5kV. We imposed a 5kV spike tolerance on the new electronic control gear. We didn't even consider that with the relatively slow switching of electronics a maximum tolerance to 1kV spikes. That was until Siemens forced us to accept the 1kV tolerance. The electronic control systems worked great. The moral of the story is avoid relay switching spikes and go for electronic switching as much as possible.
  13. Geoff_H
    Active inlet dampers could possibly be used to regulate the amount of air into cowling for regulated cooling. Many aircraft use exit dampers, a simpler and better idea to only using as much air as necessary. But inlet dampers such as that used on some vehicles could be used. Inlet restriction may reduce airframe drag, may, but the complexity and weight penalty may negate their effect. It's just a thought, my design process has always been, "what can we do different" then suggest even stupid ideas then examine possible implementation of the stupid idea. I then usually end up seeing that things as they were traditionally designed are the best. I live by the motto that there are no stupid questions just stupid answers.
  14. Geoff_H
    That's why well designed heat exchangers are contra flow. Hot flows one direction through heat exchanger, cooling fluid the reverse.
  15. Geoff_H
    In the early days of my career I did lots of work with low pressure airflow including heat exchangers. It was all designed with mathematics, get the older guys to use experience to modify the maths. The measure extensively when commissioning and alter as needed. It was very impirical. The airflow was with furnace airflow. I am sure that aircraft manufacturers go through several interactions of cowling design, I would expect that with any one off design would need redesign, a reason among others that manufacturers charge so much.
  16. Geoff_H
    The oil cooler was part of it. But there is a lot of similarities between fins and "radiator" flow. Metal cooled by air. Big difference is that the 'radiator' style has to be more complex owing to lower temperature of metal. Yes the Mooney fight was with oil temperatures.
  17. Geoff_H
    With properly designed inlet I would expect laminar flow in, the inside would then ensure turbulent flow in the heat exchanger (reynolds number drastically increasing) and exiting turbulent. One of the biggest problems is a design that works well at climb out velocities then works just as well a cruise velocities. Mooney used an exhaust duct, its opening size adjustable from the cockpit. Mooney always have temperature issues, it was a constant job to adjust the duct.
  18. Geoff_H
    One consideration that does not seem to be taken into account in this thread is that lamina flow reduces heat exchanger transfer capability. Laminar flow creates an insulating layer next to the transfer 'metal'. Velocity of fluids at a surface is zero for laminar flow. I was taught that low pressure air acts like a liquid, I also have observed wall attachment at low flows that affects the flow through heat exchangers. I believe that the only way to study this problem is with finite element analysis.
  19. Geoff_H
    A lot of expensive cars seem to catch on fire in Sydney's south west suburbs. Must be some type of self combustion in that area. Lol
  20. Geoff_H

    KR1B

    Geoff_H posted a topic in KR 1 and 2

    I can't find much information about the KR1B. Are there any in Australia?
  21. Geoff_H
    Thanks nomad. Much appreciated. I was misguided, but have seen the error of my way. Totally retired now..... well maybe not totally.. lol
  22. Geoff_H
    I was an engineer but we used the same method to discover a faulty CT. We discovered the RF radiation after an operator said that now that a ct exploded that he could watch tv again...
  23. Geoff_H
    I actually commissioned the Eraring power station end of the first 500kV power line in Australia.. the scary thing is a 330/500kV switchyard on a wet dark night it crakles and sparks. I worked at Vales Point power station when we had 330kV current transformer explosions.... Very very scary.
  24. Geoff_H
    The problem very high voltages is the corona discharge. Any sudden change of shape (eg bolts) will create an additional high voltage that can cause a discharge, between phases in this case. The mathematics of corona discharge is the same as a stress raiser on a rotating shaft.
  25. Geoff_H
    I would like to do that. Looks like Garfly wants to get the crash pictures 😁
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