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Geoff_H

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Everything posted by Geoff_H

  1. Geoff_H
    The Porsche engine failed because it too heavy compared to its competitors Lycoming and continental. I believe that one of the modern engines that use a dual cycle engine would be so much lighter. Run 1 litre at 3000rpm without gearbox, dual electrical and liquid cooled can put out 160hp. Efficiency of 40% is easily achieved! As good as any diesel cycle! Mercedes, BMW and Audi make dual cycle engines.
  2. Geoff_H
    When I got my Mooney I was told to ensure that the rear baggage door was latched and locked. Apparently a latched door had come open the door went through the tail control was lost and a serious accident ensued. I always was careful to lock mine before flight. I had the cabin door open in flight several times. I replaced the door seal with a generic seal. Wrong move. Bought a Mooney one and had no more door opening in flight.
  3. Geoff_H
    Hirth use Nikasil too
  4. Geoff_H
    It made an ass out of me no U! I assmed!!! ?
  5. Geoff_H
    My apologies to all. It is correct the power turnip does have a gearbox. My mistake arose from work that I have done on the design of low speed (3600RPM) direct drive turbines and multiple shaft engines. I assumed that the power turbine would run like direct drive after being told that the PT6 was of a similar design. Sorry. I still like the Rolls Royce 3 shaft machines. My experience with gas turbine design is from 70MW Rolls Royce Trent through to 200MW Siemens machines. Assuming has been my error.
  6. Geoff_H
    I have worked with a large GT manufacturer in the US. I worked on the instrument and controls. Recycling waste heat is not used on these turbines as efficiencies twice that of general Otto cycle engines are being achieved. Most first stage turbine blades are made by similar processes to spark gap erosion of quite exotic materials. Cooling ducts delivering air from the compressor through the blades delivering across the boundary layer of the blade. Expensive machining. Maybe3d printing methods could be used. From the prices I have seen in my experiences I cannot see how you could get high performance blades so cheap. If you are using recirculation of heat I would think that you may be able to get the price of the GT low but it asks the question of what extra weight? Also what losses in back pressure from the recycling. I do however wish you the best of luck in your endeavours. I will follow your progress and hope to see a world beater. There are other small turbines on the market similar to what you are designing so you must succeed, but how does theirs compare with your design in terms of weight and economy of purchase and fuel efficiency?
  7. Geoff_H
    A PT6 has no gearbox. The RB211and all of its derivatives that drive a shaft has no gearbox. The PT6 is a brilliant design.
  8. Geoff_H
    Difference with high speed bike and auto engines and aircraft engines is that bikes and Auto engines only do the high revs for very little time and don't contribute to overall wear to any extent. In the Mooney club we has an American race car engineer. His comment was that above 7000rpm wear accelerates to an unacceptable rate for racing long distances. My Toyota Echo motor would rev to 9000rpm, yes I used it to that speed on acceleration, but it was above 7000rpm for maybe 1%of engine time. I believe that direct drive is much better than a gearbox, obviously not shared by all.
  9. Geoff_H
    A beautiful engine. What did you think?
  10. Geoff_H
    Yes wear increases dramatically with higher speeds and who wants a gearbox? Heavy and another point of unreliability. Ok the Spitfire had one but it's design life was only 200 hours. What I am suggesting is a 3000rpm max engine producing 160hp per litre. Same technology as many Auto engines produced today. It is NOT an Otto cycle but more closely resembles a diesel cycle.
  11. Geoff_H
    My preference would be for a small gas turbine. However machining costs for a gt that has efficiency around that of a reciprocating engine are huge. I expect that 3D printing will develop to allow a high surface finish in about 10 to 20 years. This would reduce manufacturing costs to allow them to cost around the same as present as aircraft piston engines. In a GT the compressor pressure needs to be about 200psi and first row turbine blades need to have leading edge cooling with small ducts up to the turbine first stage inlet. A PT6 design is by far the best as it removes the need for a gearbox.
  12. Geoff_H
    What I am proposing is an engine that puts out twice the specific power of the Rotax 912. No gearbox, one litre displacement and 160bhp. Better fuel efficiency too. It could run on diesel or avgas or mogas or jets1
  13. Geoff_H
    I don't know about you guys but I always used full power for takeoff then backed off. At 10,000ft I only have around 120hp available. I have been to Birdsville several times, never found any person there that I would have let anywhere near my aircraft. I also propose that modern technology is far more reliable than older systems.
  14. Geoff_H
    Mercedes claim that with the modern engine technology they can get 421 up out of a two litre engine and with increased energy efficiency. Looking at engines with these technologies the extrapolated up at 3000RPM would be 320HP. No need for a heavy gearbox. Similarly a 1 litre engine would put out around 160HP. Ok extra weight would be a dual electrical system, water cooling system and turbocharger, but a 1 litre engine would be orders of magnitude smaller than a 6 litre engine. If weight increases as the lineal measurement cubed the engine may even be as half the weight. And much smaller, even with the bulk of the extra systems. This is only a thought. I am not even thinking of using automotive engines, but maybe suggesting that someone might think of designing an aircraft engine with the technologies available now. It would revolutionise the aircraft engine business.
  15. Geoff_H
    The Porsche PFM article seems one sided to me. The Mooney 201 only had one electric system but later IO540 Mooney's had two. Reliability seems good on the still flying examples and parts are available from Porsche engine spare parts. It was heavier, that kills any aircraft upgrade. I have flown one. It was so smooth, a joy to fly. The latest petrol engine cycles are similar to diesel engines, maybe a dual fuel engine would be great.
  16. Geoff_H
    Many years ago Porsche made an aircraft certified engine from their 3.3litre engine. Only one aircraft manufacturer used it. It was unusual in that it had only one control, a power wanted control. Everything else was automatic. Mooney placed it as an Porsche engined Mooney. It was however slower than the Lycoming engined Mooney. Who buys a slow Mooney. Not many people. One was bought by a Porsche fanatic, no aircraft licence, but it was just to sit in his garage. Only a handful were made. Porsche offered to refit all Mooney Porsche with Lycoming engines. But today with modern 2 litre engines reliably putting out 250BHP, with excellent fuel efficiency, could one of these engines be turned into an aircraft engine? Would they be cheaper? Would they be a dream to fly like the Porsche Mooney is? Actually 40%of the world fleet is in Australia!
  17. Geoff_H
    Thirty years ago I bought a whole heap of instruments, a few were hall effect measurements instruments. If I remember correctly you have to zero the instrument before use. Is that still the case?
  18. Geoff_H
    To measure the cables resistance accurately you have to use a Wheatstone bridge. Another problem, for accurate readings that would not be required for an approximate calculation, is the temperature of the cables when carrying a high current. It is the maximum temperature that the insulation can take that determines the maximum current that can be carried by the conductor. From memory 125 degC for PVC.
  19. Geoff_H
    A DC power metre. Having to extend cables for reading in flight would be difficult. Interesting anyway. MS6192-manualMain.pdf
  20. Geoff_H
    I think that for making a single or even a few stone lights an injection machine wouldn't be needed. A CNC or 3D printer ( both use slice code) would be able to make a plaster mould that could be used to make drape or vacuum molds for the cover. The bigger problem would be getting the LED pattern to cover the usually required light coverage. According to the design requirements the light has to cover over 180 degrees from the wings. If my research is correct the LED's have a beam angle of around 20 degrees. Hence an array of around 20 may be required, I am not sure of vertical design requirements. A CNC machine or 3D printer couldd be required for this, if I was using my machine skills would definitely be required. Not sure of wigwag requirements, I didn't know what they were until I saw them mentioned here, but I assume that their Perspex could be molded similarly.
  21. Geoff_H
    Sorry people I should have pm'd.
  22. Geoff_H
    I am looking for a system that measures the chlorine level and injects chlorine to maintain the correct level.
  23. Geoff_H
    Is the chlorinator automatic?
  24. Geoff_H
    I have made landing light covers in Perspex by making a plug from the old light cover then a mold of that in plaster of Paris. Then using Perspex made a part using draping. It turned out equally in quality to a new lense, at a fraction of the cost.
  25. Geoff_H
    Everything to do with aircraft is overpriced! Hence I am trying to design and build an aircraft for under $10k. Not sure that I am going to make it.?
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