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Geoff_H

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Everything posted by Geoff_H

  1. Geoff_H
    What operational and maintenance differences are there between a 19- and a factory made aircraft?
  2. Geoff_H
    Thanks, that answered my questions in another thread about the types of RA requirements and aircraft. Does it mean that a CTA is definitely out of bounds under all circumstances except emergencies?
  3. Geoff_H
    I am still a GA pilot, but now retired and my beloved Mooney sold I am looking for a smaller simpler VFR aircraft. Something that costs less but still gives that joy of flying. My wife hates flying so long distance is no longer a requirement. RA flying looks to suit me, however I am having trouble understanding the various aircraft tail number designations. What's the difference between 28 and 19? Why was the Morgan numbers changed. I want to limit my spending, which aircraft type should I buy?
  4. Geoff_H
    Any noise cancelling is what I would buy. I have two Bose, overpriced but good. And two cheapest type, virtually useless, give to passengers I have a grudge with lol
  5. Geoff_H
    One of the reasons for experimenting with nylon is its great engineering properties. One is its low coefficient of friction, that makes it good for low speed gears and similar. Having a lower interlaminar strength, similar to glass/epoxy structures. Hence design features such as shear stress needs to be taken into account, with metals the shear stress is so high that it's not usually needed to be calculated. Nylon is great for low speed gears where the laminations are at the vertical plane to the axis. The dimensions maybe not great in low cost printers but I have read that you can machine nylon parts, I have not tried to do this yet. I will make a part in the new year and put it in the lathe and see the results, stay tuned. But don't forget that you could make a composite aluminium/steel and nylon part using the advantages of both, Nylon can be cemented or welded to other nylon parts to make a part much larger than the bed size. I believe that this is one of the most exciting technologies to come to home aircraft building.
  6. Geoff_H
    This is a picture of the test part for the feasibility of a nylon printed flap. Notice the curve of the leading and trailing edge this could be remedied by a themally constant environment, or a heated box around the printer. It is light but not strong enough.
  7. Geoff_H
    This is a picture of the test part for the feasibility of a nylon printed flap. Notice the curve of the leading and trailing edge this could be remedied by a themally constant environment, or a heated box around the printer. It is light but not strong enough.
  8. Geoff_H
    I tried to print a flap. Each segment to be made so a thin section aluminium tube could hold together each 200mm length of flap. To get it light I had thin walls of the flap. Printed one in nylon. It did not work, the youngs modulus of nylon is low compared to aluminum. With equivalent weight the nylon part was not Ridgid enough and flexed significantly.... Maybe a different material for printing will help some day.
  9. Geoff_H
    At present it is 200 x 200. I use hairspray on glass for nylon and a variety of fiber based plates for other materials. For PLA I use masking tape.
  10. Geoff_H
    I have a modified Aldi Cocoon.
  11. Geoff_H
    Never tried the auto adjust features. I always watch the first layer very carefully and adjust as required to get best bed adhesion. I manually adjust temperatures during the print, I should put the changes in the GCode. I must do this one day. I spend heaps of time watching the print.
  12. Geoff_H
    Yes. The temperature is destroying my Teflon guides, but I have a metallic hot end on the way. One of my big problems was curling and separation of the part from the bed. I did some bed temperature measurement and found that the bed temperature was between 20 & 30 deg C below the measured temperature. Getting much better results now. Only nylon has the temperature strength and chemical resistance required. Early parts split along laminations when hit with a hammer on the vyce. To get better built quality I am building a thermal box for the printer
  13. Geoff_H
    I noticed in another thread that a discussion on 3D printing came up. I have been experimenting with printing various parts for my project. I have found that the weakest part of a printed part is the layer bonds, hence I would not use it for undercarriage parts, but for throttle quadrant rudder pedals and the like it seems to be OK. Weight is significantly lighter than aluminum parts owing to the lower density and 'honeycomb' style centre. The minimum material that could be used is nylon. Printing nylon is not for the faint hearted with much experimenting to get an acceptable product, dimension and surface finish often lead much to be desired. However my products are getting better as I solve each problem. I have had to modify my printer several times to improve the part quality. I designed each left using 3d AutoCAD then transfer the design to an appropriate language for the printing, quite cumbersome. With time I expect to be making parts that can be service sensitive in requiring strength and endurance. Maybe undercarriage parts one day.
  14. Geoff_H
    Hi Lighspeed, I am about to start cutting foam, if you're interested maybe you would like to come and have a look. I need someone to help with the hot wire cutting, wife is not the technical type. She doesn't like flying but to her credit we saw most of Oz in the Moon when we had it.
  15. Geoff_H
    OK but am at the late design stage. It will be fibreglass and foam. I am busy making templates and trying to 3d printer rudder pedals/brakes and just blew up my 3d printer.... very sad at the moment.
  16. Geoff_H
    I am not so sure. They are stressed to aerobatic levels. They are very strong. They also pioneered an aircraft foam and aluminum construction.
  17. Geoff_H
    My project at the moment is a Cri Cri like aircraft. I looked into using the model aircraft jets. They have a very low "compression ratio" indicative of a cheap compressor and hence are very very fuel inefficient, very short range. I am using 2 Hirth single cylinder engines. And also a Steel/Kevlar rollover bar.
  18. Geoff_H
    In a "dirty" Aircraft the difference between gear up and down is small and the weight of retractable gear ends up making only a small speed gain. However in the Mooney, a very "clean" aerodynamic aircraft the difference was significant. Had a gear retract problem once, gear down and the craft could not get above 120 knots, gear up it got 165 knots. OK, if it were to be fixed gear the gear doors wouldn't be a drag etc but retract can make a significant difference.
  19. Geoff_H
    Some years ago I read of a similar study in Great Britain. Theirs was 1 every 400 years, smaller country more aircraft. However near an airport I believe that the probability increases greatly for obvious reasons.
  20. Geoff_H
    I once was contracted to a large engineering consultancy. They are stock market listed and make very large profits. 'CASA charge more per hour than they do, is 'CASA very inefficient or are they returning high profits to the government coffers?
  21. Geoff_H
    I damaged an aircraft once. It turns out that unless you're actually advised that you will have to pay this excess you do not have to pay it! I did but any writing on the back of the hiring agreement does bind you for anything unless you have it pointed out to you and you agree.
  22. Geoff_H
    I have just had the same stupidity. An ultrasound showed a benign cyst on my kidney. Most people my age have them, been flying over 40 years. I had to go to a urologist and spend $200 to get a letter that said they did not affect me or my flying. The urologist found it difficult to understand that CASA did not understand that they are common and pose no problem, I had to tell him it was just CASA! With trivia like this no wonder they take ages to assess medicals. Talk about take no responsibility for their job, just charge a fortune for little responsibility.
  23. Geoff_H
    Totally agree. Only like aircraft that I Vulcan look at very closely or that I can fly or be flying in where I can be in close contact with the person flying it.
  24. Geoff_H
    All that you need now is to fly a Mooney and your aviation experience will be complete
  25. Geoff_H
    All low voltage audio cables need to be shielded. The shield MUST be rather at ONE end only. If not you can get earth loops, they will be at a multi of the engine frequency, usually double.
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