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Geoff_H

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Everything posted by Geoff_H

  1. Geoff_H
    The Mooney does not have an altitude trim on the tail. Vertical trim is achieved by tilting the tail come tilts about a pivot just behind the baggage compartment.
  2. Geoff_H
    On an RFID the speed indication changes colour with speed according to what you should be doing you don't even have to read the number just look for the colour. I love EFIS
  3. Geoff_H
    During the last 50 years of my career I programmed control systems and display systems. Most displays used digital systems for the process variables. I became very used to reading numbers rather than reading analogue systems. So my cars display digital number. I installed a digital EFIS system, I love it and read it very easily, everything in one place so no need to scan like we used to do. A mate of mine absolutely hates the number system. I guess it depends upon what you get used to.
  4. Geoff_H
    A joke told the meat by an American: What do you call a person who owns an English car with a Lucas electrical system? A pedestrian.
  5. Geoff_H
    One feature that the Mooney has is the ability for the engine to be tipped forward to work on the rear of the engine. Nice feature.
  6. Geoff_H
    I was lucky enough to see the Spitfire that col pay was rebuilding whilst it was hundreds of pieces of all different shapes and sizes on the ground. 250k rivets. Every rivet needed to be drilled out to an oversize and re riveted. In wartime the design life of the aircraft was 200hours. Rivet holes were oversized for the rivet. This allowed the ladies making the Spitfires, the unsung heroes, put an aircraft together quicker.
  7. Geoff_H
    Yes don't go near those damed fangled flying machines, the good old horse for me ?
  8. Geoff_H
    Toyota Patent Suggests a High-Compression Diesel Truck Engine May Be in the Works Toyota look like they are developing a high efficiency engine. Toyota Supra already use a dual cycle BMW engine. 40% efficiency announced in the article is huge. Best Otto cycle engine efficiency available is around 30%. Increasing the range of an aircraft or better still free some aircraft weight up for other purposes.
  9. Geoff_H
    Turbo, I have heard about sparkles engine technology. I thought at one stage my vehicle may have had one. However I found spark systems. Are they for starting, what can you tell about sparkless engines. Attached images is my engine with the cover removed
  10. Geoff_H
    I have been researching dual cycle engine after I noticed that mine has a relatively low inlet manifold pressure at full power. I believe that the manifold pressure for 260hp/lire@3000rpm may only need to be about 2bar. Consider the first part of the cycle, Otto cycle with a charge of full air some fuel ignited by the spark plug. Pressure extremely quickly rises. Normally in the Otto cycle this pressure would decay as the piston moves down. But now convert to diesel and inject fuel in a constant pressure diesel cycle. In reality it does drop but not as much as an Otto. The pressure vs volume graph shows this rise then not decaying as much. I have not read that this is the case, but seems plausible.
  11. Geoff_H
    The Hurricane had more kills than the Spitfire. Sure it attacked slow moving bombers, the Spitfire fought fighters in general. Buy the Hurricane had one huge advantage over the Spitfire, it's availability was significantly better. A bullet through the wing of the Hurricane was a simple airfield patch, the Spitfire was so complex that offer the smallest damage needed to be repaired at the factory with complex equipment. I believe that both aircraft deserve the same amount of adoration.
  12. Geoff_H
    I would expect the manifold pressure would be somewhere in the 2.5to 3bar, Mercedes did not publish a lot of data on their current technology limited engine. The efficiency is higher than a diesel of the same compression ratio, so this would reduce temperatures somewhat. Specifically designed pistons and crankshaft would be needed. I do think that your comment about gyroscopic effects could be a very real project killer, in a car not significant, in an aircraft very significant. The dual cycle starts every cycle as an Otto cycle, then becomes a diesel cycle on gasoline. Given that given the same compression ratio an Otto cycle engine is more efficient than a diesel the dual engine uses the constant volume of the Otto to increase the pressure in the cylinder then starts injecting very high pressure gasoline in a diesel cycle constant pressure. Best of both cycles. Many manufacturers are now using it. Some are saying that they may drop diesel engines from their range as these engines offer better efficiency.
  13. Geoff_H
    I read from a Mercedes engine that would normally run st 6500RPM. 215HP from 1 litre. Any combination of speeds are possible. Not a lot of extra HP from 6500RPM so why use a gearbox? Extra weight for little gain. However from the little interest shown here for a dual cycle engine with a massive HP per litre and 30% promote fuel efficiency over an Otto cycle I thought that people on this site had little interest in such an engine. I certainly drive two cars, both with the dual cycle engines and am amazed at hp and fuel efficiency. I think that a reduction in size of an aircraft engine from 5litre to one litre would reduce the weight so much that the weight of liquid cooling and dual electrical would be great. More range from increased efficiency.
  14. 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.
  15. 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.
  16. Geoff_H
    Hirth use Nikasil too
  17. Geoff_H
    It made an ass out of me no U! I assmed!!! ?
  18. 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.
  19. 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?
  20. 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.
  21. 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.
  22. Geoff_H
    A beautiful engine. What did you think?
  23. 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.
  24. 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.
  25. 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
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