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Sun Aug 6, 2017 20:00

Our lad thinks two strokes are the best of all. Despite the problems of overheating and the difficulty of lubrication being adequate over the entire rev range he like Scott has already figured out that direct oiling is the way to go and the removal of oil from the fuel meaning that the mixture can be dialed in properly.

The breakthrough he needs will come when he understands the crucial importance of a properly designed exhaust using cones and reversed cones to create an expansion chamber whilst maintaining the necessary back pressure to keep the cylinders stuffed yet keeping the extractor effect that ensures the exhaust pulses are cleared enough to allow the next to expand.

Toad notices that various motorcycle engines seem to have caught onto some of these features but no one has yet put them all together being mistakenly convinced that each feature on its own is responsible for the improvement in engine performance. Villiers, for example, were fitting some nifty expansion chamber boxes fed by the down pipes and kept playing with their volume and shape not realizing that the Brooklands style silencers were preventing the necessary back pressure.

So theres a rich vein of techno babble being set up for readers to enjoy and to give the right atmosphere in the hangars whilst largely avoiding the specifics of actual aircraft engines likely to be encountered at the time. However I am quite confident that this techno babble, as a topic between pilots and mechanics is entirely realistic because it existed between my mates and I during the biker years (much to the disgust of most female company).

  • Nicely done... - Sarge, Sun Aug 6 19:07
    ...and welcome back. So far nothing of note to worry. Lets throw a little engine theory at you, so you can weave it in where it fits. One thing about in-line four-stroke engines is the matter, as you ... more
    • For clarity at the off... - Sarge, Mon Aug 7 07:19
      It occurs in my mind that these technical excursions might be construed as either timewasters, focus-destroyers, or the unwelcome scrutiny of the anorak. If there ever is any feeling of, "Oh God,... more
      • Not at all - mike, Mon Aug 7 12:08
        Quite the reverse! I've been keeping a tight rein on my personal preference for technical detail and discussion. BTW I think you misread that first part of the new story. I am emphatically not... more
        • I really can't say... - Sarge, Mon Aug 7 16:03
          ...regarding the rotary as a two stroke, because I am not all that conversant in two stroke engines, other than knowing they can be atmospherically sensitive, which is not a good thing regarding an... more
          • Theres a definite bias - mike, Mon Aug 7 19:33
            Amongst engineers against two strokes and its largely based on a chimera, thats to say the experiences from the past when technology wasnt up to the task. Since they do twice the work they have half... more
            • That being the case... - Sarge, Tue Aug 8 06:59
              "I love them" should stick with that as a story element. However... I raise the question from a grave suspicion there must be a reason why, with all the advantages of weight and power output,... more
              • Steambird - mike, Tue Aug 8 09:53
                I have that book too. I know some British inventor did fit a steam engine into an airframe tethered to a short stretch of rail which developed enough lift to break free - if memory serves? Sir George ... more
                • For bikes and cars... - Sarge, Tue Aug 8 11:38
                  ...I'm with you on two stroke being viable, and in some cases advantageous. Can't have rallyed a Saab 96 without marveling. I well remember the two vs four schools in bikes, though I understood my... more
                  • Well that just makes things better - mike, Tue Aug 8 14:15
                    Do you know that I hadn't considered those aspects of the changes in atmosphere that you spoke about? Should have done though but I simply dismissed it as a problem similar to that of changing... more
                    • That's probably wise, BUT... - Sarge, Tue Aug 8 15:59
             might not give up on the debate as a good character development tool. I suspect Colin, being the automobile fan, is a four cycle guy, and might hold user prejudices to that predilection. Then... more
    • Good! - mike, Sun Aug 6 20:00
      • 2 stroke rotary - mike, Sun Aug 6 20:56 I, like Toad, am a fervent admirer of two stroke engines. I have had some great motorcycles with 2 stroke engines and as in my story it occurred to me -... more
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