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Geoff_H

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Everything posted by Geoff_H

  1. Geoff_H
    The designer of the CozyIV, Natt Puffer, said that the only things that can be added to the aircraft are those things that pass the following test: When you throw it into it it stays in the air! ?
  2. Geoff_H
    I had a case split open in my Mooney. The acid destroyed the case and some of the airframe. Cost a considerable amount. It taught me a lot about batteries. We think that the regulator was faulty and cooked the battery leading to overheating and cracking of the case. Regulator was replaced.
  3. Geoff_H
    How is what you are saying and different to my statement? I just wanted everyone to know what I found out, the hard way. I was not countering anything you said. Some aircraft have car batteries, some aircraft batteries. They are slightly different.
  4. Geoff_H
    If you are using an aircraft battery be aware that they are different to car batteries. The charged voltages are different! Car chargers don't work as well on aircraft batteries.
  5. Geoff_H

    Jabiru overweight

    Geoff_H replied to rendrag's topic in Jabiru

    CofG behind centre of lift will make unstable aircraft. Centre of lift needs to include lift +/- from tail and fuselage.
  6. Geoff_H
    Flashing lights during the day (or night) have another good purpose. They frighten wild life away. Flashing apparently represents a pulse and this is not something that they want to mix it with. Good for outback landing. The Qantas flights into Kalgoorlie used to flash landing lights to scare the kangaroo population of the strip.
  7. Geoff_H
    And both a sunrise and sunset over water. It is one of the destinations that I must get to one day. The restaurant only operated six or so months of the year. You may have to take certain foods in for the chef to cook. All reports of the glamping are fantastic.
  8. Geoff_H
    Ok I am now retired. All the time to go flying. Wife hates flying these days.....she use to go with me sometimes. Been married over 50 years but I don't like going places without her. Real dilemma. Hence my project is only single seat ??
  9. Geoff_H
    I expect that they would correct a badly designed system. I expect that most if not all engine design engineers know of the problems that hiclones solve and prevent them from occurring. I owned a BMW some years ago, that used their M44 engine. A truly great engine. It had a variable length inlet manifold, short at high power for less losses in inlet pressure and long at low powers for better air fuel homogeneous mixing.
  10. Geoff_H
    In the steam power industry this happens all the time. It is wall attachment. A low flow of air, less than turbulent if my memory serves me right, will flow against one wall and not mix. I have done velocity traverses of ducts at low volume and found that the air was only using around 25% of the available duct. As the volume increased the flow became turbulent and filled the whole duct evenly ,(except dropping to zero velocity at the wall). If this is happening in an engine inlet manifold you have some problem with a ventury carb. Too big a carb will often give worse performance.
  11. Geoff_H
    Valve guides, timing gears (could be fibrous, or belt though)
  12. Geoff_H
    CASA produced a warning about using 98 fuel in aircraft some years ago. It has dissolved gasses in it. Their vapour pressure is low. On a hot day it is possible for these gasses to come out of solution in fuel lines and starve the engine of fuel. Each aircraft design needs to be checked for 98 in fuel lines at altitude on hot days.
  13. Geoff_H
    Yes you are right. I should have said the best operation conditions for cruise.
  14. Geoff_H
    A better gauge would be CO. When the value just starts to rise above zero best performance. Another gauge is residual oxygen in exhaust. Both are monitoring the combustion b
  15. Geoff_H
    M61A1 those gas turbines that you work on, are they Siemens gas turbines? Are they near Dalby? Vibration analysis is simple. Get a set of vibration traces, use a program to convert the vibration to frequency and amplitude (fast Fourier transform maths) using an ap freely available. Then look for things that happen at the largest frequency, how fast the machine is going, meshing speed of gears (all in hz). Finding a match in frequency will usually lead you to the problem.
  16. Geoff_H
    Vibration analysis is another very useful NDT tool. In industry the X, y and z axis vibration signature will be taking after commissioning. You were able to have other machines to compare with when something went wrong. I see all NDT as a health check, seeing possible problems long before they show up a problem. The best results for these tests is no result. Vibration analysis is really terrific for gearboxes, Meshing frequency can show a tooth starting to have problems. Good thing is that you can check the vibration with a mobile phone. I was able to determine the natural frequency of my house by measuring its vibration when the metro tunnelling machine passed under next door's house. Useless information, could be useful to earthquake proof the house ?. Ok I just love engineering, from 14 years of age when I discovered what an engineer was until now at 72. Now I just design my project.
  17. Geoff_H
    I no longer need these oil testing kits. They are prepaid just posting cost to USA. Free to anyone that wants them. Useless to Jabiru engines and 2 stroke engines, any others wanting them please pm. My project uses 2 stroke engines so no further use to me. Used this brand when I had the Mooney
  18. Geoff_H
    For vibration on fixed surfaces I use my phone. There are a number of fast Fourier transform analysis apps that will also give data as to what is exciting the vibration. I clamp my phone to the surface.
  19. Geoff_H
    I had oil filters cut open and magnetic full as well. The major reason for oil testing was detecting engine problems from wear etc that has started but is not able to be detected by any other means. I flew the craft every week where possible. As a professional engineer I have always been a believer in preventative maintenance. Aircraft engines are the same as automobile engines. Automobile engines are used for far longer than aircraft engines and have no mandatory overhaul times. Most wear in my Mooney came from the engine idling waiting for the oil to get to temperature so that the constant speed propeller or the pistons getting hot before the bore and ceasing would not happen on take off. Is appreciate that engine failure in visual conditions usually only means an outfield landing, with possible damage. Night flying is far more dangerous, I have not done it for years. now that I am older and suffering from the normal degredation of night vision.
  20. Geoff_H
    I often flew in IFR in the dark, night VMC in the outback. Engine failure would probably meant my death. Maybe that is why I put so much emphasis on engine health. I don't think that there is any economic value, unless when buying an aircraft it could alert to an engine with issues.
  21. Geoff_H
    Blackstone would disagree, failure can be detected long before anything is obvious to the naked eye. The smallest of quantities show up with a mass spectrometer. They can even say if an engine is not wearing in properly. Many owners of top end GA aircraft do testing from engine new or overhaul. I find it interesting that it appears that LSA owners don't see the value in oil testing as a preventative measure.
  22. Geoff_H
    I have used these people. Aircraft | Blackstone Laboratories
  23. Geoff_H
    It can be done in Australia, just need mass spectrometer. But with an aviation specialist they will give heaps of additional information, they need to know what engine the oil is from. It is not that expensive when considering the cost of an outfield landing. Magnetic particles in oil tells you about a condition of the engine a long way into a failure. O paid around $400 for around 10 samples, plus USA postage.
  24. Geoff_H
    I am just wondering how many of us subscribe to NDT of our engines. After all the engine is rather critical to sustained flight. How many get their oil condition tested to see upcoming engine problems? How many know many different conditions, including piston wear can be determined well in advance of them happening by sending off a sample of oil to one of the many condition monitoring places?
  25. Geoff_H
    The goggomobile used the generator starter motor, the one device for starting the engine. The engine was 2stroke. 4forward gears, 4reverse gears. For reverse start the engine in reverse. Gas turbines for power generation use the generator as a motor, when up to a speed where combustion can continue, turn off the motor, run the turbine up to speed and connect the generator. Modern car engines have big generators to supply the electrical load, I wonder if these could be used to start an engine, maybe just push the engine to a position where spark ignition could start the engine.
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