| Author | Message | ||
     Jlnance |
The thing that make Badweb great is that someone will actually answer this question.  I have some experience writing computer simulation software. All my experience is with electrical, I don't know much about mechanical simulation. But that doesn't stop me from being curious. When Buell designs an engine, I assume part of the process is to simulate it. How detailed is that simulation? Is the actual combustion of gases, and the propagation of flame fronts modeled? Or are things modeled at a higher level? | ||
| M1combat |
I would think yes, but I'll let those that know answer for sure... | ||
| Awprior |
Jim, I work as a structural analyst for one of John Deere's plants. Basically, I look at designs, model them using FEA and determine what is good or marginal (nice name for bad). The big push is to go for doing all product validation and verification by computer. The work I do (mostly construction vechicles) is hard to predict what loads and accelerations a particular component or system is going to be subject to. We have to rely on field test data to determine what we run our models with. Engines... Haven't done any work with them, but based on my experience with some less involved structures (take a modal analysis of a bracket attached to an engine, no really good way to know how it reacts without testing) it'd be somewhat difficult to model it. If you're looking at combustion, flame propogation etc, haven't heard or it. Heat transfer, yeah, but not to the level you're talking. I'm sure someone, somewhere could figure out how to so it, but it's not going to be me! | ||
| Jima4media |
Jim, The basic design for the Buell motor was done in 1955 on the back of a napkin. The Harley Sportster motor was created long before computer modeling. There have only been incremental changes to the design since then. It is time to throw that napkin away. Jim | ||
| M1combat |
Why? It keeps me ahead of any bike I choose to stay ahead of in the twisties... In the straights... Whatever... Why? It's a STREET BIKE. | ||
| Steve_a |
There's quite a bit of sophisticated modeling going into the Buell engine. Finite element models of the entire structure have been done. Also, the entire intake and exhaust system have been modeled in great detail with a number of proprietary gas dynamics/flow systems, including WAVE. | ||
| Bomber |
actually, the basic design was done in the 1800s, and it's shared with all 4-stroke engines -- {grin} me, I think the napkin's doing fine, thanks . . . there are other napkins available that'll satisfy the need for more torque, more HP, different colling, more valves, don't think anyone's runnin more cams . . . . decide what level of performance ya need (or can handle, most can't outride their present sleds, yet yearn for more), and go from there with your purchase, yes? or, if it makes ya happy, by the trickest spec sheet you can afford and enjoy that Buell's doin some very leading edge stuff, as Steve_a sez -- (Message edited by bomber on June 27, 2005) | ||
| M1combat |
There's always something that can be assumed about a pilot that blames a loss on his machine... | ||
| Iamike |
Don- I love your passion! Sure we could ride a bike that makes 150hp that will go 180 but it is tough to beat the simplicity and 60+mpg ( do the new ones really get that?) My old S3 will get 65 mpg at 60mph if I would only ride that slow. Normal riding it drops to about 53. | ||
| Blake |
"It is time to throw that napkin away." Why? Because other engines of comparable power are more efficient and cleaner running? Kinda hard to argue with 65 MPG out of a naked sportbike with a 103 HP engine. Pretty much unheard of actually. And it meets 2008 CARB specs with no catalytic converters, and no nasty poisonous ethylene glycol engine coolant. Gee Jim, I'd figure you were a more astute environmentalist and opponent of gas guzzling vehicles than your post would lead one to believe. Granted, for those who want max power per cc, yes, a different engine configuration makes sense. Who knows what the future may hold for Buell motorcycles. Heck, I'm still liking my '97 Cyclone. The XB12R is calling to me though.  So is the R1200GS. Hey, that's another underpowered air-cooled engined bike. I must be silly. Granted I did have many very bad experiences with an overheating Yamaha in my past. I still recall the day at Oak Hill Raceway, out practicing the week before the next race. A racer friend from Tyler was scowling at his Honda CBR600 as I prepared for another session on the track. Seems his CBR600 couldn't withstand the heat and was belching steaming hot water onto his right leg and boot after a few laps in the 90oF Texas Summer heat. He'd been frustrated by this before and tried richening the mixture, removing the thermostat, new pump, cleaned/new radiator, but nothing he tried solved the problem. He did arrive at a final conclusion on the problem as I began to pull away towards the track. As he pointed at my bike, he said... "I wish I had one of those air-cooled Buells." Not sure what all today's Buell engines have in common with the 1955 Sportster mill, the V-angle, the common crankpin configuration, air-cooled, two overhead valves per cylinder, and a primary chain drive. Should Ducati and BMW scrap their air-cooled engines too? What about Moto Guzzi? We can ask for a new design without suggesting that the existing proven one be "thrown away." BTW, how is that Sportster derived XR750 mill doing in the flat track arena these days where it competes against the latest and greatest Japan Inc. has to offer? Not too bad eh? Still competitive eh? Throw that napkin away? I don't think so Jim.  | ||
| Doughnut |
It is time to throw that napkin away. HELL NO! I'm not done! | ||
| Road_thing |
90oF Texas Summer heat Well, that may be summer heat up there in east Texas, but it sounds like a pleasant spring day down here! By the way, Blake, my invitation to bring Mrs. Blake down to the Ranchito is an open one--just name the day. ...uh, you did say she could string barb wire, right?  rt | ||
| Jlnance |
Thanks for all the info! | ||
| Court |
>>>There's quite a bit of sophisticated modeling going into the Buell engine added by Court: and other key components of the frame, body and structure | ||
| Blake |
RT, She'll do the fencing just fine like her daddy taught her; she prefers to have the electricity off though. I know, I know... He spoiled her.  | ||
| Road_thing |
No electricity? Hmmph. Kids these days... | ||
| Jima4media |
90 degree heat is nothing. Try racing across the Sahara desert or in the Baja 1000. How many air cooled engines have won those races in the last 20 years? Has a Harley motor ever won? A: 2, No. In the past 20 years, has an air-cooled motor ever won an AMA Superbike, World Superbike or Grand Prix race? A: No. There is a big gap between mythology and reality. Jim (Message edited by jima4media on July 03, 2005) | ||
| Blake |
I agree, there is a big gap between mythology and reality. When is the last time a liquid-cooled IL4 that revs to 15,500 rpm won any desert race, ever? There is also big gap between a Superbike racing engine or a MotoGP engine and a street bike. If that were the benchmark for street bikes, there would need be no 600cc middleweight machines as they would all be 250cc two-strokes. Still waiting for you to explain the amazing success of the antiquated air-cooled Harley-Davidson XR750 in dirt track racing. Is that a myth too? Your contrived requirement to have won the race is convenient. However, it was just a few years ago that American racer Jimmy Lewis finished the Dakar race very respectably on an air-cooled BMW Boxer based entry. He even won a stage or two. I don't understand why anyone would limit their view of a street bike engine on whether or not it had ever won a strenuous off-road endurance race. Uh... to what mythology are you referring there Jim? | ||
| Blake |
If Buell can continue the trend in development of their air-cooled engines, the future looks very bright. In ten years they've improved reliability, efficiency, and emissions, and nearly doubled the HP of the 45 degree air-cooled, pushrod V-Twin engine. More work ahead? No doubt. Throw the engine configuration away and be like everyone else? Not likely. | ||
| Jima4media |
Blake, Wasn't it you that brought up running air-cooled versus liquid cooled motors in hot weather? I agree that Harley has had a long history of success with its antiquated air-cooled motor. Mostly because of Harleys influence over the AMA on flat track racing. Remember when the Yamaha TZ750 was outlawed for being too fast? http://www.amaflattrack.com/article.php?UID=vAdTYSpfwjNSmO07rTLceQBQJAKIrf&sc=10 63&aid=3895 When watching the SuperTracker series, I saw Suzukis walking away from Harleys a lot of the time. What manufacturer has won the Daytona flat track race for the last couple of years? Not Harley, they didn't qualify. It depends on the length of the track as to whether teams will run a KTM, Rotax, Yamaha, Honda, Suzuki, Triumph, or Harley. All but the Rotax and Triumph are liquid cooled. The XR750 motor's days are numbered. Winning is a Contrived Requirement? If NOT winning a race event is a criteria, anybody could enter anything, and feel happy. Anyone who is satisfied with coming in 10th is a loser. Ducati, and Moto Guzzi don't race their air cooled motors. BMW does in the Boxer Cup, but that is being replaced by the Power Cup, IL4 liquid cooled motor next year at Daytona. When did I ever say there were IL4s in desert races? The weapon of choice is the liquid cooled KTM 660. Can an air-cooled motor still be upgraded? Sure - 4 valve heads, turbo-charging. 60, 75 or 90 degree V-Twin instead of 45 degree. 6 speed transmissions. Further work on fuel injection and air management. Will any of that be done this year? I doubt it. (Message edited by jima4media on July 05, 2005) |
