| Author | Message | ||
     Sarodude |
Blake- I recognize your point and already acknowledged it in my post before you mentioned it. A cooling medium that doesn't boil off or leak can be an advantage in certain situations or to certain consumers. Do you believe that, as currently implemented, the XB cooling system keeps engine temps (and, presumably, physical dimensions) as stable as water cooling systems do (also as currently implemented)? Would more stable temps & dimensions have any advantages? Obviously, this all goes out the window if you've boiled over your water. I guess in my experience I experience over-cooling an air cooled motor INFINITELY more than over-heating water cooled motors (driving up Chiriaco Summit between Ca / Az in the Slowyota LOADED with junk, a passenger, AC to the max, dropping under 85 mph only when impeded by traffic in 110+F weather, running 87 pump octane without a ping, water temp never budging from where it was this morning in the 40's). -Saro | ||
| M1combat |
I say True Blake... And I assume you're talking about jet engines? I don't mean to answer for Blake but... No Saro... It certainly doesn't. But for the design goals it's an excellent implementation. I have a KL600R that's water cooled. I hate working on the thing, but it's a thumper that makes almost 9K RPM... | ||
| Brucelee |
My main contribution to this thread is my experience with a new 2002 ZX6-R. This was water cooled and it was a real pain in the ••• in the summer. The coolant temps varied between 160-227. When at 227, the fan threw off an amazing amount of heat, mostly right on my legs. I can remember sitting at traffic lights, fan blazing and legs on fire, sweating my ••• off. Contrast the XB, which is MUCH COOLER in the heat. Moreover, since I added the right side air scoop, it is cooler even still and the engine fan stays off. Limited experience I know, but I would not go back to WC unless I totally loved the bike. For me, the AC has been the way to go. PS-Buy the right side air scoop. I think Al has them now. | ||
| Xlcr |
That post from the desert was interesting. I have a commentary on the Desert War written by an officer of the Luftwaffe in service with Rommel's Afrika Corp. In it he mentions that the FW190 equipped with an air-cooled radial was far superior for use in hot desert conditions than the BF109 with it's water-cooled Daimlier engine. He said the reason was that in those conditions eventually the coolant in a water-cooled motor would become as hot or hotter than the engine itself, at which point transfer of heat from the engine to the coolant was no longer possible, and the engines would seize up. The air-cooled engines, on the other hand, would never do so because no matter what, the desert air would always be cooler than the engine's cooling fins, and so heat transfer would always be present. Now, I'm not an engineer or a scientist, but I believe that is just basic physics that in order for heat transfer to happen one medium must be cooler than the other. Does anyone else have anything to contribute? | ||
| Perry |
Ummm.... The point of a radiator is that it transfers the heat from the liquid coolant to the air. So, in a way all engines are air cooled. Some directly, and others are cooled by liquid which is cooled by air... and if the liquid isn't cooled enough by the air it can no longer cool the engine (as you pointed out.) Sounds like the german radiators were inadequate for the environment and didn't dissipate enough heat to cool off the liquid coolant. But the german radiator has little to do with it really. Like most any engineering exercise, it's all about tradeoffs. Liquid cooling offers a more narrow and predictable operating temp. range and smaller engine block (that's nice for several reasons) at the expense of more complexity and parts that can leak/fail etc. as well as the bulk and ugliness of a radiator (not nice). Erik opted to tradeoff in favor of simplicity because he can create an air cooled engine that delivers what he wants. Just as with Harley Davidson, when the day comes that a different criteria and desired tradeoffs call for a water-cooled solution (i.e. VROD) we will see one. As long as the criteria Erik chooses favor air-cooled, we'll continue to see air-cooled. It's not religion guys, relax. In asking for water cooled, you are essentially asking for Erik to change his design goals and tradeoffs. That may or may not be a good thing depending on your preferences, but it would certainly mean a change to what a Buell is, as we know it today. | ||
| M1combat |
Agreed, but a Buell with a water cooled twin or V4 making 140HP and 30lbs lighter would be a SWEET ride. I'll most likely not sell my 12R for one, but I'd buy another Buell  . | ||
| Perry |
a Buell with a water cooled twin or V4 making 140HP and 30lbs lighter would be a SWEET ride. You and I agree on that... so long as I don't have to rev past 10K to get it... but apparently Erik doesn't seem to think it is that important. For now at least, he outvotes us. | ||
| Buellerx |
a Buell with a water cooled twin or V4 making 140HP and 30lbs lighter would be a SWEET ride. V-MAX VROD VXB? | ||
| M1combat |
I'd settle for XB-12X4 or something like that. I could care less how far I have to rev the bike so long as it has good low end power, great mid-range and a nice head rush. | ||
| 2hogs |
Blake, Thanks for banning that Neutron character! All, I'm no expert on motorcycle design and thought the trilogy of tech and mass centralization were just marketing buzz words -- until I experienced them for myself. I rode my 12X back to back with a friends ZZR1200 and experienced front end plow for the first time while on his ZZR. The little 12X handles that much better in the curves. That said, could a water cooled mill be shoehorned into the XB frame and would it effect the things that make the XB handle better? Then again is there anything to gain by a water cooled mill? Maybe if you want to do 160mph in the straights and carve the corners! Me? I like the current design just fine. Keeps me from losing my license and helps me stay young :-) Cheers | ||
| Tommy_2stroke |
Blake: Falconbridge, N.S.W. New South Wales, Australia. | ||
| Brucelee |
The Pros and Cons of Air Cooling! Engine cooling From Wikipedia, the free encyclopedia. (Redirected from Air-cooled) Jump to: navigation, search Engine cooling is the process of cooling an engine by using either air or liquid. As engines generate mechanical power they also generate waste heat energy because they are not perfectly efficient. The engine must therefore be cooled to prevent it from cooking in its own heat. Although some waste heat goes out with exhaust gases in most conventional internal combustion engines, further cooling is needed otherwise some components will get so hot that materials or lubricants will fail. Cooling can also apply to weapons, which can be thought to be included within the scope of engines, and is often used in machine guns, since their high rate of fire generates a lot of heat. [edit] Basic principles Most internal combustion engines are "air-cooled" or "liquid-cooled". Each principle has advantages and disadvantages, and particular applications may favor one over the other. For example, most cars and trucks use water-cooled engines, while most small airplane engines are air-cooled. Most liquid-cooled engines use a mixture of water and other chemicals such as antifreeze and rust inhibitors. Some use no water at all, instead using a liquid with different properties, such as ethylene glycol. Although the term "liquid-cooled" is used here, most air-cooled engines also use some liquid oil cooling, and most liquid-cooled engines subsequently cool the hot liquid with air. Conductive heat transfer is proportional to the temperature difference between materials. If an engine metal is at 300°C and the air is at 0°C, then there is a 300°C temperature difference for cooling. An air-cooled engine uses all of this difference. In contrast, a liquid-cooled engine might dump heat from the engine to a liquid, heating the liquid to 150°C which is then cooled with 0°C air. Thus, in each step, the liquid-cooled engine has half the temperature difference and so may need as much as twice the cooling area. [edit] Advantages and disadvantages Cooling, however, is also limited by energy (heat) density. A small, very hot component is difficult to air cool because air has low heat density. If the air speed is low, then there is only a small mass of air to carry away heat. Since there is little mass, the air which is cooling the part gets nearly as hot as the part, and then the temperature difference is small so cooling is poor. Blowing more air over the part improves cooling, but blowing air fast creates noise and uses power. (Doubling the air speed may take eight times the power). In contrast, liquids have much higher heat density and so a comparative trickle of liquid can keep the part cool. A major reason that heat density is important is that the most significant cause of engine failure in modern engines is hot spots. The engine as a whole may be cool enough, but if one part of the engine overheats, the engine eats itself. Slight overheating makes the engine wear out faster and gross overheating causes the engine parts to fail quickly. Common hot spots include parts of the cylinder head, exhaust valves, pistons, and cylinders. Unfortunately, many hot spots are small and located where it is difficult to blow sufficient air over them. Furthermore, engine materials are not perfectly conductive, so it is often not possible to "cool at a distance" by building a metal bridge to a place where it is easy to blow a lot of air. Liquid-cooling is thus a good solution to a difficult problem, but sometimes it is even difficult to move enough liquid coolant to keep a part cool. When liquid coolant gets to an engine hot spot, it may boil, expand to a gas, and momentarily stop the flow of coolant over the hot spot -- which then becomes even hotter. When more coolant reaches the hot spot, it simply boils. The gas bubbles may disappear again as they mix with newly circulated coolant, and the hot spots may be damaged by localized boiling even though the radiator contents are not unusually hot. Indeed, the engine temperature sensor may indicate the engine is running cool overall, even though one part is dangerously overheated. In an air-cooled engine, the coolant is already a gas and thus cannot boil. Thus, while air-cooling makes it harder to avoid hot spots, air-cooling also tends to limit sudden hot spot problems caused by boiling coolant. Using air-cooling eliminates an entire engine subsystem and at the same time eliminates problems with coolant freezing. It simplifies engine design and can lead to markedly better engine reliability, though the benefits of reduced complexity must be traded against reliability problems caused by worse thermal control. Using air-cooling also eliminates the coolant radiator and the weight of multi-wall engine parts needed to capture the coolant without leaks. Air-cooled engines are thus often lighter per unit power than liquid-cooled engines. However, cooling fins on an air-cooled engine can be expensive to make compared to liquid-cooled engines, even though liquid-cooled engines require tricky hollow construction. The liquid in a liquid-cooled engine also serves as sound insulation. An air-cooled engine must ensure good passage of air over the engine and thus it is difficult to substitute some other kind of sound deadening. In addition, using air to cool small hot parts means air must flow faster than for the radiator of a liquid-cooled engine, even though the air-cooled engine has much greater temperature differences to aid cooling. For both of these reasons, liquid-cooled engines are typically quieter for a given power output. Liquid-cooling makes it easier to maintain each part of the engine at a given temperature in normal operation. Air-cooled engines can have the hot-spot problems described above, and getting enough air to the hot spots may cause other parts of the engine to run too cold. Liquids have less temperature rise as they absorb waste heat. Thus, the coolant temperature varies less with engine load. In turn, more even temperature of liquid-cooling means better component tolerances can be maintained, which can improve both durability and emissions. It may be possible to achieve good temperature control with an air-cooled engine, but at the expense of more complicated thermal management and increased weight. Similarly, peak power from a given displacement of air-cooled engine is typically limited compared to water-cooled counterparts, so liquid-cooled engines may be heavier but also fit in a smaller space. [edit] Difficult to generalise For all these reasons, it is difficult to make generalisations about air-cooled or liquid-cooled engines. Air-cooled Volkswagen kombis are known for sometimes "eating engines", with both rapid wear in normal use and sometimes sudden failure when driven in hot weather. On the other hand, air-cooled Deutz diesel engines are known for reliability even in extreme heat, and are often used in situations where the engine runs unattended for months at a time. It is usually more difficult to get either low emissions or low noise from an air-cooled engine, two reasons why most road vehicles use liquid-cooled engines. It is also often difficult to build large air-cooled engines, so nearly all air-cooled engines are under 500 kW, whereas large liquid-cooled engines exceed 80 MW (Wärtsilä-Sulzer RTA96-C 14-cylinder diesel). A reliable generalisation is that for a given power level it is more difficult to build a light liquid-cooled engine. Weight is one reason air-cooling is common in aircraft engines, though reliability through simplicity and ready access to cool air are two other reasons. | ||
| Kowpow225 |
Very interesting... POD boy again? (and again, and again) | ||
| Redstar100 |
I think Falconbridge is in canada http://reference.allrefer.com/gazetteer/F/F00269-falconbridge.html | ||
| Hippo888 |
Riding bikes, I've noticed that aircooled bikes are generally more comfortable to ride in hot weather. Water cooled engines are able to dump a lot more heat, and that heat has to go somewhere. Unless it's properly ducted, that heat usually ends up toasting the rider. | ||
| Martya |
whoa!, ref the focke wulf 190 air cooling against the Bf109's water cooled motor, well it's pretty irrelevant to compare aircraft with earthbound vehciles, wizzing around the skies at 15-20,000ft in a fighter you will find that temp's are way lower than ground temp's whether its in the desert or not. as for the debate on air vs water cooling i have experienced both the pro's and con's, picked up cylinder bore on a norton motor because of overheating through insufficent air flow, (although it was about 105.f). roasted nut's?, suprising how getting a spray of boiling coolant get's your attention!, a stranding with a holed radiator with my KTM in the desert. now that's a time when you WISH you had AIR cooling!. | ||
| Xlcr |
Not exactly. Over Europe they whizzed around at 15-20,000 Ft, but that's because they were fighting a strategic war there against Allied bombers, and the bombers were that high or higher because the Germans had every possible target surrounded with clouds of flak. In the desert it was very different. They and their opponent, the British 8th Air Force, were fighting a tactical war. There were no strategic targets in the desert, only enemy troops and tanks, and to hit them you had to fly low and in the heat. That's why the 109s radiator suddenly became insufficient to the purpose. Of course, a prop-driven air-cooled plane has the advantage that the prop itself is very effective at pushing air over the engine, but then, the same could be said for the prop of a water-cooled plane pushing air through a radiator. | ||
| Spatten1 |
I don't know that Erik Buell necessarily prefers air cooled engines. He is given a Harley engine to evolve. It is not like Buells have newly designed clean sheet air cooled engines. I would be curious what he would choose in an engine if given free reign. Even aside from cooling, would he want four valves per cylinder or overhead cams? I'd love to hear his opinions on many engine options that he may or may not have input on with Harley. | ||
| Dago |
If Erik chose/had the ability to use overhead cams, water cooled, or anything other than the pushrod v-twin he currently uses, would it still be a Buell? Would there be an entire board filled with people talking about how ridiculous it would be to put a v-twin in their beloved Buells?  hd v-twin | ||
| Sarodude |
Given that the VERY first Buells were 2 stroke, 750cc square fours, I wouldn't hold Erik to the 45 degree common crankpin V twin.... That engine setup would be about as far off from what we get with current Buells as possible. -Saro | ||
| Spatten1 |
Wow Saro, I had no idea. Sounds like he was copying the hot GP engine configuration at the time, but adding CCs. I'm certainly impressed. | ||
| Sarodude |
Spatten- Those were in fact race bikes destined for AMA Formula 1. See Dave Gess' site for some good info. -Saro | ||
| Blake |
"Would there be an entire board filled with people talking about how ridiculous it would be to put a v-twin in their beloved Buells?" Pretty sure there are boards that fit fairly well that description. They may have even been launched and promoted from right here on BadWeB.  Bit the rest of the answer is that I and probably a host of other BadWeBrs would likely not be part of it. I'd probably be riding a Ducati Supersport or an air-cooled Monster, or a BMW R-bike. If I wanted a repli-racer for the street or a naked version of one, I have plenty of options that are tough to beat. I know it is a very personal thing, but nothing much irritates me more in a street motorcycle than having to spin it up to over 10,000 rpm in order get to the peak HP. | ||
| Spatten1 |
I get a woodie spinning street engines up to 12k+ rpm feeling the surge last soooo looong. I love the typical hard hit at 6k, and really hard hit at 8k or 9k that just keeps pulling really hard for another 4k. Bad engine for me though, I need something slower because I'll abuse the 4IL, which isn't cool as I have a full family to take care of. Riding a 4IL for me at 5K is like riding the XB at 3K. I just figure I'm below the real power but not even half way to redline, so it is really easy on the engine. I don't mind spinning those short stroke engines because they love to rev and will do it all day. The low rev V-Twin has it's own personality that I really dig too. At this stage in my life it is definitley the right bike for me. | ||
| Court |
>>>>I get a woodie spinning street engines up to 12k+ rpm feeling the surge last soooo looong Mind they whirly parts, lest they seek communion with the sun. Note sure who said that first on teh NYC boards, but it still makes me chuckle | ||
| Dago |
>>>>nothing much irritates me more in a street motorcycle than having to spin it up to over 10,000 rpm in order get to the peak HP. Keep they lumps tightened, lest they vibrate to a crumbled mess. Truthfully, I can't tell you what I like more. But reason leads me to believe both options have their place. Therefore, I'll take both. | ||
| Brucelee |
http://www.gizmag.com/go/1158/ I often forget how ridiculously fast a two stoke air cooled engine can be. | ||
| Spatten1 |
Bruce, I believe the 500's were all liquid cooled engines. | ||
| Old_man |
One of the reasons I bought a Buell(XB9S)is the engine. I like the V-twin, air cooled, hydraulic lifters (no need for adjustment). It produces all the power I'll ever use, with no need to constantly stir the gearbox. If I wanted a bike with the most horsepower (that I'd never use) I'd have bought something else. Improvements can be made and have been made, but the basic design is perfect for me. | ||
| Old_man |
P.S. It gets great gas mileage. I average around 56mpg. |
