Monday, July 9, 2018

Motor Porn

Not sure this is legit - but it should be.


  1. Could be legit. That's about the right size for a 1/5 or 1/4 scale engine.

    1. This is not a scale model. This is an actual purpose built
      9 cylinder radial engine. My resume includes air and gas
      compressor mechanic, Millwright, maintenance mechanic and

      My father was an air compressor mechanic. He once asked someone
      which piston weighs more (a large LP aluminum piston and a smaller
      cast iron HP piston.) The correct answer is they both weighed the

      When it comes to radial engines, you will never find an even
      number of cylinders. they are all 3, 5, 7, 9 or two banks of
      odd number cylinders. It is all about balance. Only in-line
      engines can support odd numbers of cylinders because of counter-

      I have worked on reciprocating compressors that were driven by
      by 5,000 HP elecrtic motors. Starting with Ingersoll Rand
      PHE's, these 2 cylinder compressors were horizontally opposed.
      Their HHE's added 2 or three banks. Not one of them had counterweights.

      The most naturally ballanced engines or compressors are boxers.

  2. I saw one of these at a car museum in England a few years back.

    There were 3 prototype radial engine motorcycles built by Peugeot that were used in boardtrack racing in 1930's. It was a powerhouse compared to the Indian's and Harley's that had been dominating boardtrack. It had problems with exhaust heat, getting it started, and a gyroscopic force issue that made it a difficult bike to ride.

    1. The gyroscopic effect only applies to balaced spinning masses like
      flywheels and tops. As a mechanic with more than 40 years in the
      trades, I can tell you that "gryoscopic forces" do not even come
      into play. All radial engines have an odd number of cylinders.
      This is a conscession to balance.

      I own a 96 CI Harley Davidson. The engine in this photo is more
      balaced than my twin cam V-2 but that does not equate in any way to
      centripetal forces! As a science geek at age 14 I understood Newtonian physics.

    2. Gyroscopic precession also effects an airplane when the spinning prop is changed to either ascend or descend, requiring opposite rudder to hold the nose in line....don't know if presession would apply to a radial engine without a spinning prop....

  3. Here's the story on this bike.

    If the story is to be believed it's not a Peugeot engine. It's a scaled up copy of an RC airplane radial engine. 100cc displacement.

    1. Fascinating! That radial motor fits in so well that I'd have sworn it was actually 1930s, but the bike's original motor was apparently a 100cc single. This motor looks perfect!

      First working steampunk bike I've ever seen!

  4. Scale models of 9 cylynder radial engines did not exist in the early
    1930s. This is an ACTUAL motorcycle that would have dominated Harley
    Davisons and Indians back in the old days. I am an HD fan with a
    96 CI chppper in my garage. This is a genuine scooter!