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Geoff_H

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Everything posted by Geoff_H

  1. Geoff_H
    "That's all fine but the math doesnt lie." That is if you have the right maths. After years of calculations and observations of actual air flow in ducts believe me it is far more complex than simple maths. Everything from zero wall velocity to air viscosity etcetera. Best idea is to observe what works on a similar installation and copy it
  2. Geoff_H
    Personally I think it is but I am not writing from any point of knowledge. It definitely has more strength at temperature. 95% of what I use is epoxy.
  3. Geoff_H
    Many years ago the epoxy landing gear on the Cost IV often sagged with time. The cure was to 'cure' the epoxy by constraining the legs and heating them for several hours without any load on them. The suggestion was to stop them in black plastic and put them out in the summer sun. It was claimed that there was no sag on undercarriage legs so treated. I don't have details not numbers. It does make a little sense when you look at prepeg fibreglass with uncured fibreglass is placed in a mould then heated to cure it.
  4. Geoff_H
    It is a polyurethane foam with glass/ epoxy skins. Attachment to the glass epoxy using a glass balls/epoxy mix, that never failed. The foam failed in shear at the centre. I have searched for data on composite strengths, the best advice I got was that data was very expensive to get and guarded very much. Some years ago I had organised to do a Master's in Aeronautical, my project would be to determine a calculation system for composites. I got a contract just as I was about to start, never got back to it. Too old now.
  5. Geoff_H
    Thanks, great information. I am only aware of people making composite aircraft using a skin of epoxy glass or foam with a fibreglass double skin. With the exception of the very advanced aircraft construction similar to the Boeing aircraft. I have been building using a foam covered with glass/epoxy. I have been unable to determine the strength of the combination by calculation. I quess a combination, construct it and then test to destruction and use the values found in the test as the value for design. I think that finite element analysis maybe the way to go. All my tests have failed by shear stress at the centre of the foam. The layers of glass/epoxy remained intact in the testing, but it was deformed. But will the structure take significant cycling? Will it fatigue? Maybe I should make a test rig.
  6. Geoff_H
    Thinking about the fatigue in aircraft brings another question to mind. The designer of the Cozy IV stated that composite fibreglass does not fatigue. I don't know that I believe him. Anybody know anything about composite aircraft fatiguing?
  7. Geoff_H
    There are several kits to build your own EFIS at home. There are also EFIS' for your smartphone. Anyone have any experience in any form with these?
  8. Geoff_H
    Steel has a stress level below which fatigue does not exist. Aluminium does not have any point at which does not fatigue. The design level is statistically derived with a nice safety margin....however is your aircraft aluminium as per design? Inspections are important. As Nev commented salt erodes aluminium and I think that it reduces the fatigue failure points (not sure).
  9. Geoff_H
    It is not the wires melting that the current rating is based on it is the maximum temperature that the insulation can stand. With the Tefzel wire (a Teflon like product with less lethal gasses given off in a fire), you can use a smaller gauge wire, a weight reduction. Digital signals don't require a high current, not even the power supplies, but you never know what will go wrong. Murphy was an optimist!! I would never again solder, I had so much trouble, even with heat shrink, then I was told to crimp....now I always crimp. Only use non oxidation gold connection. In my younger days we carried ink erasers to clean dirty signal connections. Gold was a saviour. No good getting a failed digital signal for lack of quality connect systems.
  10. Geoff_H
  11. Geoff_H
    I think that you are right Nev. I should have researched a little more. I was so pissed about my car I was on the verge of demanding my money back when they fixed it
  12. Geoff_H
    When I picked up my car in 2019 the 3G and GPS were interfering with each other. Data was being stopped and the GPS had me in the middle of McCarrs creek. The two antennas are in the only little enclosure at the rear of the roof. Overseas did not have this problem, so they said. In Australia we often use the lower end frequencies of 4G as their range is better, especially near where I live. Well some Germans came out with a lot of test gear and it looks like the problem is solved. The FAA is worried that 5G will interfere with their GPS equipment as I believe that the frequencies are very close.
  13. Geoff_H
    My Mooney had gap seals. They appear to work very well.
  14. Geoff_H
    I sure do. 74. It was Matt Hall's dad that tried to make me sick with aerobatics. Never a moment of sickness, loved every second of it.
  15. Geoff_H
    I had a ride in vh+FTA doing aerobatics not that long before the accident.
  16. Geoff_H
    I know, I needed a very small amount for rebuilding a compass. That was the only size available in WA at the time. Seems a waste to just throw it away.
  17. Geoff_H
    A little off track of this conversation but I have a bottle ( one litre I think) of compass oil free to a good home.
  18. Geoff_H
    Light or not so light that should be 😒
  19. Geoff_H
    I learnt on a C150, flew aircraft from C150 / 6 seater retractable through to Mooney and most recently a C152. What a lot of BS that you can only fly light or heavy. I am sure that I could fly a single seat 500lb craft. Backed off from buying a Teeney Two after a report of flying them as being a " religious experience".
  20. Geoff_H
    When I was consulting to the mines a good friend was doing velocity surveys for wind power. He said wind cost 4 times gas turbines. Never quite sure what he was about but he did say it was an expensive installation (interest on investment?,) And you still need to have a gas or diesel power plant. The overwhelming amount of energy is in trucks and loaders....a solar panel on the roof of the trucks, or maybe a wind turbine? One panel in a sunlit day produces enough energy to drive a Tesla 4km. 5MW motor on a dump vehicle may be just too much LoL
  21. Geoff_H
    Sorry left a zero out, should be 30,000,000 litres of diesel. Getting old and forgetful lol
  22. Geoff_H
    One of the biggest carbon emitters are mines! One particular iron ore mine, a confidentially agreement prevents me from disclosing much) burns 3,000,000 litres of oil per month. Hydrogen powered machinery would prevent this diesel/explosives from emitting. There must be many mines also with high emssions. Most electricity is from burning natural gas from the pipelines in gas turbines (hence my involvement).
  23. Geoff_H
    I have worked in WA and met a few people that have worked with Twiggy. He is a great guy and is truly interested in the community. His grandfather Lord Forest was a great guy also, he did a lot to develop WA. He doesn't have an office he sits in a big room with all other employees. He does huge effort promoting the aboriginal.peoples lifestyle.
  24. Geoff_H
    It looks like Twiggy is backing hydrogen. Liddell power station has been making hydrogen by electrolysis since the 1971. Just a much larger scale.
  25. Geoff_H
    I worked on designing a 185MW gas turbine in Florida. Highest aircraft jet/ turbine is 70 MW. I must admit that our blade technology was from Pratt and Whitney under licence. We had many more stages and ran at 3600rpm with a single shaft. Big external burners. Well the principles are the same. Worked on an A380 Rolls Royce in the outback, gt part fantastic, the way rolls Royce converted it was an absolute shambles. Every install in the world had big problems. Aircraft GT's use the same principles, but the ones over approx 70MW are very different. Below 70MW much similar.
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