Boxers


Why are BMW air-cooled engines called "boxers"?


From: svoboda@rtsg.mot.com (David Svoboda)
As posted to: rec.motorcycles


Well, you see, the name comes from the fact that all BMW bikes (with the exception of that current abomination) use shaft-drive for turning the rear-wheel.

How does a shaft-drive imply the name "boxer", you ask? Well, the VERY first shaft-drive bike was of course the Spagthorpe Boxer, an experimental design of the earlier years of the company. And that motorcycle has quite the history, quite the history.

The best theory of the time said that if you were to use longitudinal crankshafts (the Spag models of that time were all opposed-triples, so had two cranks) with a shaft-drive turning in the same direction, the motorcycle would be wheelie-unstable. That is, under strong application of counter-steering, along with the requisite roll-on throttle, would produce an uncontrollably violent wheelie. (The theory is quite complicated; suffice to say that the waffle-cone had not yet been invented.)

Well, Lord Julian and his trusty engineers knew a seductive challenge when they saw one, and rose to the occasion. They invented the wheelie bar, but not like the ones we have now for drag-racers. No, their wheelie bar consisted of a bicycle wheel mounted to the back of the bike, barely touching the ground, such that when a wheelie occurred and the bicycle wheel was pushed upward against a spring, it would pull in the clutch proportionally, thereby smoothly keeping wheelie-equalibrium. (This design was so unquestionably effective that you still see it in automotive testing grounds to this day.) This wheelie-stopper system was necessary because such a system could respond with super-human speed, to counteract the incredibly instant loops that would otherwise inescapably result.

So, the Spagthorpe Experimental Model 105nSD was created. First ride was on the secret Scroddum-Srattche Proving Grounds. The engine was started, and with a staccatto bark the machine took off. First turn, the pilot applied a strong counter-steer, rolled on the throttle....and crashed. The pilot didn't have a clear picture of what happened, or a clear picture of much of anything. He was bruised and bleeding, but only in the facial area. Hmmm. They replayed it on their slow-motion moving-picture device the next day. It seems that the wheelie device worked admirably except for a little feedback oscillation problem; the front wheel popped up, and just before it looped, the clutch disengaged and it lowered back down. Unfortunately, the pilot couldn't quite get out of the way of the rising instrument cluster, so recieved a solid thwack, right in the face. Of course, he was still holding the throttle open, and the countersteering force, so as soon as the clutch re-engaged, WHAP, and again, WHAP, and WHAP and WHAP WHAP WHAP! Faster than the eye could see, the pilot was beat about the head and face until unconscious, and then lost control and crashed.

Coincidentally at that point, the Spagthorpe Testriding Union went on strike. So, Lord Julian, still needing to test his concept, went to the local college and recruited the toughest young men they had to offer: their amateur fighting club. On them, the facial bruises and lacerations were not even a concern, and Lord Julian was able to soon find the correct feedback settings, finish the research, and from that time forward, in honor of the valient college men who came through in a pinch, the Spagthorpe Experimental Model 105nSD was called the Spagthorpe Boxer.

A supercharged version of the Boxer showed up for much touted race on a quaint little island just offshore, but unfortunately the entire race bike and equipment wagon was stolen just before the race started. The culprit was never found. Lord Julian doggedly put the entire ugly incident behind him and went on to his next project; the famous Spagthorpe Rottweiler.

Incidentally, rumor has it that one of the striking test riders was at that time dating a young woman, a lovely German girl by the name of Mercedes (last name was lost to history). Now, I certainly would never want to accuse a fine company of anything untoward, but coincidentally a few years after the unfortunate Incident on the Isle, an upstart company in Germany began manufacuring their own version of the "Boxer", except they carefully limited the engine output and frame design, such that it was absolutely impossible to countersteer, thus eliminating the danger of wheelies, and relegating acceleration and turning performance to somewhat lackluster proportions in the process. To this day these design compromises have made all shaft-driven motorcycles impervious to countersteering or wheelies, and has radically limited the performance of these cycles, even though the compromise is completely unnecessary with transeversely mounted engines. It's a gray-area in motorcycle design, you see, and no modern company will do such testing, as they do not have the committment, determination, or sheer gall of Lord Julian Spagthorpe.

So, I hope that sufficiently answered your question about "Boxers".


Dave Svoboda (svoboda@ranger.rtsg.mot.com)  | I think God's got a sick
90 Concours 1000 (Mmmmmmmmmm!)              | sense of humor, and when
84 RZ 350 (Ring Ding) (Woops!)              | I die, I expect to find
78 CB400T Hawk (Baby Honda)                 | Him laughing...
AMA 583905  DoD #0330  COG 939  (Chicago)   |         - Depeche Mode


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