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old man emu

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Posts posted by old man emu

  1. should i add something to my transmissions to say i'm unfamiliar with the area?

     

    Too right!. The radio is a communication device to be utilised for increased safety. Never be afraid to use it for that purpose.

     

    By rights, if you are using the published reporting locations, you are doing the right thing. Use of these over-rides local custom. However, when in Rome, do as the Romans do. If some one calls up and gives their position using a location that you cannot identify, then jump back on the radio and ask for clarification. If you let people know that you are unfamiliar with their area, and don't want to endanger other aircraft, then you'll soon find out where Bill's old cowshed is.

     

    OME

     

     

    • Like 1
    • Agree 2
  2. What is the real difference between the terms "forced landing" and "crash landing"?

     

    To my mind, a "forced landing" is caused by one or more of

     

    a. loss of the ability of the airplane to continue normal flying - caused by engine malfunction; fuel exhaustion, or airframe malfunction.

     

    b. deterioration of weather conditions to a level below which continued flight towards planned destination, or away from areas of adverse conditions would be unsafe

     

    c. incapacitation of crew or passengers which prevents safe operation of the airplane, or rapid access to medical assistance on the ground.

     

    A "crash landing" is the impact of an airplane with water or land which results in damage to the airplane, and may result in injury to pilot and passengers.

     

    Therefore, a "crash landing" can result from circumstances that would not be considered to have initiated the need for a "forced landing", and a "forced landing" may not result in damage to the airplane or injury to pilot or passengers.

     

    OME

     

     

    • Like 1
  3. No. I'm saying be aware that OAT not only affects the amount of Lift generated by a wing, and the power generated by an engine, but it also affects the performance of a carburetor and the whole fuel system.

     

    Also, it's an argument against adding alcohols to fuels used for aviation, and support of avgas (being a much more constant product)

     

    OME

     

     

    • Agree 1
    • Caution 1
  4. I've written elsewhere about the Partial Pressure of a volatile liquid and the effect of temperature on it and therefore its rate of evaportation. The problem that RichTee faces is due to the decrease in Partial Pressure as a result of heating.

     

    Evaporative emissions depend mainly on ambient temperature, fuel volatility and fuel system design [8]. As far as the fuel is concerned, Vapour Pressure (Dry Vapour Pressure Equivalent - DVPE) is a key parameter: higher values of DVPE, which is measured at 37.8 °C, mean that the fuel is more volatile or, in other words, that more fuel will evaporate at that temperature. The range of vapour pressure of Avgas is 40 - 50 kPa while that of Mogas is 45 - 100 kPa. This brochure from BP provides a bit of easy-to-read information: http://www.bp.com/content/dam/bp-air/en/Files/Fuel/Air%20BP%20Avgas%20leaflet.pdf

     

    When blended with gasoline, ethanol is known to cause an increase of the ethanol/gasoline blend DVPE compared to the base gasoline, up to a point, then decrease it.

     

    Here are two research papers that deal with petrol/alcohol mixes.

     

    http://publications.jrc.ec.europa.eu/repository/bitstream/JRC36839/6839%20-%20EVAP_Final_Report_final_isbn.pdf

     

    OME

     

    OJN_203_ Vapor Pressures of Alcohol-Gasoline Blends.pdf

     

    OJN_203_ Vapor Pressures of Alcohol-Gasoline Blends.pdf

     

    OJN_203_ Vapor Pressures of Alcohol-Gasoline Blends.pdf

  5. Just did a rough calculation for Density Altitude using this data: Airport Altitude 5000, QNH 1024 OAT 45C Rel Hum 10% and this gives a Density Altitude of about 9000 ft. Can this be a cause of poor performance, or are you noticing vapour locks?

     

    OME

     

     

  6. The object of a leak down test is to determine how well pressure is held within the combustion chamber of a cylinder. This is done by introducing air at a known pressure to the cylinder via the spark plug hole, and observing the ability of the sealing elements (rings and valves) to hold that pressure. Therefore a leak down tool has two gauges. One to measure the introduced pressure, and one to measure the pressure within the cylinder.

     

    The two readings are compared and reported in the order- Cylinder Pressure, Introduced Pressure eg 72/80. The results may also be reported as a percentage (Cylinder Pressure divided by Introduced Pressure x 100 [72/80 x 100 = 92%]). It must be noted that these results are dimensionless ratios, and are compared to a manufacturer's published minimum requirement for the engine. If the result falls below the minimum requirement, then further inspection and repair is required.

     

    Since the result is merely a comparison of the readings of two gauges, then, as long as the gauges are of similar accuracy, then the quality of the gauges is not of great concern. In purchasing a tester, I would look at whether the kit contained adapters for 14mm and 18mm spark plug holes, and how the valve controlling the introduced pressure. For a Jabiru engine, you should supply 80 psi, so you also need a compressor that will produce and hold that pressure. AND - CAUTION . Doing this job is dangerous. You need someone to hold the prop against the introduced pressure. If you don't you could get a nasty whack.

     

    I had a look on Ebay and I think that this one: http://www.ebay.com.au/itm/0-100PSI-Leak-Down-Engine-Cylinder-Leakage-Gauge-Tester-Testing-Auto-Tool-Kit-/161617083624 would suit your needs. I assume that you are an owner, wanting to be able to check things before you head off to an maintenance shop.

     

    The one I looked at had a nice carry box, which is important in protecting the tool and for keeping all the bits and pieces together.

     

    Old Man Emu

     

     

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    • Informative 1
  7. Welcome, Russell.

     

    The wife and I were in Abergavenny in January 2013. Unfortunately it the weather wasn't pleasant so we didn't have a good look around.

     

    Then we lost our dog. "So if you see a red dog running free, then you'll know he is mine."

     

    Old Man Emu

     

    Sorry, but I've been waiting years to use that line.

     

     

    • Haha 1
  8. [ATTACH=full]39061[/ATTACH]

    "Oh, Bunty. To you it might be a Sopworth Explorer Mark ll, fitted with a normally aspirated, in line six cylinder Rolls-Fairley engine and an in-flight adjustable MacByrne Claymore propeller, but to the rest of us,

     

    It's a Man!!!!"

     

    OME

     

     

    • Like 1
  9. After considering the Facts presented and the photograph, and relying on 28 years' experience policing traffic law, the only offences I think that I could prove 'beyond reasonable doubt' are:

     

    1. Drive Unregistered Motor Vehicle (On the road, it is a vehicle propelled by an engine of some type - the Law does not specify the means by which the power of the engine is used to move the vehicle, and it is not designed to run on rails, so it's not railway rolling stock.

     

    2. Drive Uninsured Motor Vehicle (Compulsory Third Party Injury insurance - which cannot be issued to a vehicle which has not passed a roadworthy inspection. Depending on the date of manufacture of the airplane, it may not even be required to meet some Australian Design Rules for motor vehicles - it would need a stop light at the rear as a minimum, and a shroud around the propellor.)

     

    As for the serious charge of Endanger Life etc, you would need to prove an incident that actually endangered the Life, Health or Safety of a person. Obviously the vehicle was under control of a competent person as it traveled along the road (a twit, maybe, but still competent to stop and start the vehicle). Its motion could be stopped at will (see how it's parked), and the engine could be stopped. All I can see is "Potential Danger", and there's potential danger whenever a vehicle of any type - engine, wind or animal powered - is put in motion.

     

    I hope the bloke is going to use the airplane for display as he's going to be up for a whack replacing the wing spars.

     

    OME

     

     

    • Informative 1
  10. I happened upon this little shop while I was having a walk around the Barangaroo Park at Darling Harbour, Sydney. It sells aviation related books. The ones I looked at were mostly from World War One and were letters and reminiscences of pilots. There were a number of other categories, but I was short on time and could not explore everything. Not being in a position to buy anything, I didn't ask about prices, but he did tell me that he sold an original manual for a Clerget engine for $150, which I think is a reasonable price for an rare antique book.

     

    The owner, Marshall SILVER told me he that his wares range from the WW1 period to about 1939. They seem to be mainly from the USA (I think he is an American).

     

    If you are looking for a rare book you can contact him on 0448 488 407 or by email at [email protected]. If you are in The Rocks, the shop is at 8 Argyle Place, Millers Point. I'd call before going there on the weekend, just to see if they are open.

     

    OME

     

     

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