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Geoff_H

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Everything posted by Geoff_H

  1. Geoff_H
    The Cherokee that I owned in 1980 cost $11k, I spent about $15k in non operation costs plus. Sold it for $11k after two years. Loved the aircraft but I needed to move from the country to the city, had to sell all toys. My Mooney cost $120k I spent $120k on updates and improvements. Sold it for$120k. Don't regret it at all. Loved that aircraft, used it in my business, saw most of Australia. Wife hates flying, when I retired I had no real use for it. So I sold it. I don't regret owning it. I hope that the guy that bought it is having fun now.
  2. Geoff_H
    Having had two GA aircraft the best two days in ownership are the day you buy it and the day that you sell it!!
  3. Geoff_H
    I remember in the late 80's. The manufacturer insurance per aircraft built went through the roof after a few big payouts. Aircraft went from a low cost (if my memory serves me right around $20k) to something like $150k (again memory). Cessna and piper stopped making singles for some years. This was truly a huge impediment to flying. From then aircraft were being repaired not replaced. Bloody lawyers. geoff
  4. Geoff_H
    Mooney's have laminar wings with small pieces of angle attached to the leading edge. These are set in the factory in order to balance the wings, they are usually in slightly different vertical positions. When I would stall the Mooney I owned it would drop the left wing first. Maybe they needed readjusting. I think that the stall was the left wing becoming turbulent.
  5. Geoff_H
    The prop wash comes from the nose wheel. From memory the net was just behind the nose wheel and two ropes with poles pulled it up when airborne and lowered it as appropriate. Cannot remember details, old age has set in, but I will do it to the cozy if I ever finish it, very unlikely.
  6. Geoff_H
    I have seen a design of a net that was lowered and was in a position to protect the prop on landing. If I ever finished the cozy I was going to install one
  7. Geoff_H
    The Bede 5 had a similar drive system. I expect that it has been solved in this aircraft. The long not so stiff drive shaft with a high inertia prop at one end and a pulsating engine on rundown broke the tailshaft. Solved with a one way sprag clutch. Look for vibration problems.
  8. Geoff_H
    Two of my test pieces. Glued together with 5minute epoxy, and clamped for 24 hours. I couldn't separate them with a hammer. I was surprised at the strength. I will make the flaperons in nylon carbon and epoxy, 12 inch a piece and glue them together. I am in error in no welding in a previous statement, the exhaust will be welded.
  9. Geoff_H
    My printer seemed like a bargain. Unfortunately it was the end of a design that was crap, a new design followed. To print the more exotic materials I had to redesign significant parts of it. It now has a water cooled high print temperature. It took nearly 2 years of design, build and redesign over and over again to get to where it is. The effort is now paying off. The advantage of 3d printing is that I do not have any need for welding. Even the engine mount will probably be an exotic high temperature material
  10. Geoff_H
    When I was learning to fly around 1980 I was taught how to swing a prop. Safety and getting out of its way were important. Prop swinging does not seem to be taught these days. I have needed to start my engine several times, the guys doing it for me were much younger than me. I had to teach them. It took 5 minutes.
  11. Geoff_H
    The more that I do the more I get amazed with what I can do. My flaperons look like being 3d printed
  12. Geoff_H
    Only steel part is the rod, all else either nylon or carbon Nylon.Tyre has 50 psi in it, held ok for a month
  13. Geoff_H
    Hey the bond between layers is welding in a most controlled manner. I have.made wheels amd forks etc. Interlayer strength is ALWAYS tested. You wouldn't believe the testing method, crude to say the least. The layers are hit with a 10 pound hammer in a manner that puts shear stress on the bond. However one must know how to print to get the best results. I will send a picture soon. I am so impressed with printed parts that the engine frame will be 3d printed.
  14. Geoff_H
    Maybe you could make joints for the aluminium using 3d printed joiners. Each time would be round and secured by a pop rivet. Using Nylon infused with carbon the joints would be light and strong. Each joiner would need post printing preparation using a reamer in each "hole". A printer could make around 3 joiners per day, probably as fast as they could be used.
  15. Geoff_H
    I have used it extensively in industrial applications. It works great, but I want to use it in my project. I am just wondering about the consequences of using in an aircraft. Would anyone use it as a locking device for wheel retaining nuts?
  16. Geoff_H
    Has anyone had experience using Loctite style locking of aircraft bolts? What type of locking did the Loctite style glues replace? Nylon, metal crimp, wire, split pin?
  17. Geoff_H
    I have sent mine back to the Bose at Silverwater. They fixed them for free
  18. Geoff_H
    Years ago landed a Mooney with one brake locked on. When the speed dropped to around normal braking speed the locked wheel took over and the craft ground looped. It stopped very quickly indeed. Wheels going sideways can do that. Assuming that one brake is working, quite possibly so, then maybe just applying both brakes will result in a ground loop stop.
  19. Geoff_H
    Actually as a general rule speed harmonics tend to reduce dramatically as the number of cylinders increases. I remember being taught in 3rd year of degree that a V12 was regarded as the first "fully" balanced engine, well the vibrations were considered insignificant. I don't know about this engine but I am not about to get the books out to calculate the effectiveness of this configuration. Interesting to note that there is a theory that a 'square 4" with contra rotating shafts should be considered extremely well balanced,. mmmm how heavy would that be?
  20. Geoff_H
    Props change their section as the diameter changes. The Reynolds number also changes according to, among other things, that is a function of lineal speed the position on the prop. These things change the drag of the prop at a point along the shaft, the overall torque required by the prop is the integral of the torque along the entire length of the prop. This should match, or be slightly lower than the available engine torque. This should be analysed for the aircraft to ensure that the aircraft can get into the air. At max aircraft speed the prop angle of attack to the air vector, this should be the best lift/drag ratio for the aircraft ( lots of factors affect what ratio is best). The best technique for prop design is to use finite element analysis for the aerodynamics of the prop. I created a crude finite element program some years ago. It generally produces results that are close to operating wings (actually it was designed for helicopter blade design but is the same as prop design). It also calculates stress along the prop. An important factor.
  21. Geoff_H
    Many years ago I owned a Cherokee. I could not really afford it then. I opted to insure the passenger liability for $250,000 a seat. At the time I was told by the insurance agent to make sure that I killed passengers and didn't maim the that was much cheaper.
  22. Geoff_H
    Sorry Nev, I was replying to the radio controlled turbo
  23. Geoff_H
    A scaled up version could be quite cheap. But it is very inefficient. You could expect fuel consumption to be many times what a Rotax would burn for the same kw. Efficiency depends upon the compression ratio, here I expect about 4:1, and the turbine inlet temperature TIT. The higher temperatures that your blades could take the more efficient. I expect that a turbo prop would be many orders of magnitude higher in cost.
  24. Geoff_H
    My preferences are for gas turbines. Simple design, very light for the power output if compression ratio is high. With metal 3d printing the number of parts could be reduced to very few. 60%efficiency has been obtained with high temperature turbine blades. They can run on virtually any fuel. Even coal!!!!! On India a gas turbine station was built using coal, well it made coal gas first, fed that to a bank of gas turbines then burner the coal char in a fluidised bed boiler they generated using steam turbines. A small gas turbine with high efficiency would be either very heavy or very expensive. But I would love to power my project with one. You can also get two stroke engines that run on diesel with low pressure injection. Light weight high output. Not sure of the efficiency
  25. Geoff_H
    The seat would weigh more than the aircraft. But love the thought. Unfortunately the seat in the aircraft forms part of the structure as a bulkhead, yes single seat. Love your comment lol
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