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  • Radial Engine Starting Techniques

    From Ken L@21:1/5 to Charles K. Scott on Fri Nov 6 23:01:49 2020
    I flew the Convair 240 which had two Pratt and Whitney R-2800 radial engines. The aircraft was designed by airline pilots in 1949 and had all the latest technology. The engines were started by electric starters that were powered by a small petrol engine
    located in the tail, much like the APU's of today's jets.
    The procedure was to use the starter motor to run the engine through "5 blades". Usually the ground crew has already turned the engines by propeller to ensure that there is not a lot of oil sitting in the lower cylinders which would cause a hydrostatic
    lock and most-likely blow a cylinder off the block. By motoring the engine for 5 blades you are confirming the engine is not locked plus circulating a little oil. After the 5 blades you introduce fuel through a toggle switch and high voltage spark to
    combust the fuel. The magnetos are on and will provide the normal charge to the plugs but this high voltage switch really ensures a smoother start. As you toggle the fuel switch you slowly advance the mixture and the engine will start to run on its own
    and you can release the fuel and high voltage toggle switches. The co-pilot counts the blades for the captain on the number 2 engine. The captain counts blades on the number one. It really did take two pilots to get an engine started to make a smooth
    transition from start phase to run phase. There were hands going all over to keep the engines running. The captain's right hand would work the start toggles and his thumb was pushing up on the toggle that activated the start switches.
    It was a lot of fun flying that old bird. In my later career flying jets you just push the start button and monitor temps. Too easy!

    On Wednesday, November 3, 1999 at 7:00:00 PM UTC+11, Charles K. Scott wrote:
    In article <[email protected]>
    Phillip Hopkins <[email protected]> writes:
    I wonder if someone, who is knowledgeable on the subject, could describe the
    methods used is cranking over large radial engines during starting, such as those on B-17s, B-29s, B-36s, even DC-3s. A brief history of radial engine starting techniques from the 1920s to the 1950s would also be very interesting.
    Thanks in advance.

    Phillip Hopkins
    Having sat in the jump seat on many occasions of the company DC-3 that
    my father flew back when I was a kid I can verify that an electric
    starter was used to get the engine going. B-17's used Wright Cyclones
    and they were started by electrical starter as well. Same for the
    B-29's and B-24's.
    In watching flight deck operations from many documentaries and films I
    can verify that many of the Navy's WWII aircraft used electric starters although I think the F4F may have used a starter cartridge.
    Corky Scott

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  • From Ken L@21:1/5 to Jim Beasley Jr. on Fri Nov 6 23:02:52 2020
    On Sunday, November 7, 1999 at 7:00:00 PM UTC+11, Jim Beasley Jr. wrote:
    Why don't you buy the engine manuals? They will provide the best source of information.
    Many motors are direct drive from the starter, and some use an inertial starter. That is interchangeable (R1340). The old P-36 used a shotgun
    shell to get it going.
    Phillip Hopkins <[email protected]> wrote in message news:[email protected]...
    I originally posted this on rec.aviation.military, with surprisingly no
    takers.
    Among my colleagues, we have had much discussion about the methods used in starting large radial engines - though none of us have any real knowledge
    on the
    subject. We have guessed that some very large engines use a flywheel
    energy
    storage mechanism which is somehow coupled to the engine crankshaft at
    start
    time. The suggestion was also made of the use of gas cartridges which are
    used
    to operate an air motor which turns over the crankshaft, a la the movie
    "The
    Phoenix" with Jimmy Stewart.

    ******
    ******

    I wonder if someone, who is knowledgeable on the subject, could describe
    the
    methods used is cranking over large radial engines during starting, such
    as
    those on B-17s, B-29s, B-36s, even DC-3s. A brief history of radial
    engine
    starting techniques from the 1920s to the 1950s would also be very
    interesting.
    Thanks in advance.

    Phillip Hopkins





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