| Author | Message | ||
     Boltrider |
Which is more aerodynamic? Awhile ago I was arguing with a vendor on my truck forum about this. I was saying that if you take for example, a Z06 vs an R1, the Z06 would produce a better aero number and would be more slippery in the wind. He called BS, saying that motorcycles perform much better in the wind tunnel. My proof is anecdotal using power/weight comparisons, but he wasn't buying it. What say you Badweb? | ||
| Firebolt020283 |
I would say that the motorcycle would be more aerodynamic because it is smaller and would therefore make less of a hole in the air. | ||
| Slaughter |
Power and weight have nothing to do with aerodynamics. | ||
| Ft_bstrd |
From the R1 forum: Total drag (Dt) and drag coefficient (Cd) are two completely different but related things. Cd is equal to the coefficient of parasitic drag (Cdp) plus the coefficient of induced drag (Cdi). Cdi is minimal on motorcycles though so it can be effectively disregarded. Total drag (in lbs) can be found by multiplying the Cd, dynamic pressure* (q), and the surface area (S). * dynamic pressure is made up from the density ratio (local air density accounting for local altitude, temperature, and barometric pressure measured against standard density) multiplied by the air velocity in knots squared. The resultant of that is then divided by 295. The formula looks like this: Dt=Cd(q)S As you can see drag is determined by five factors. Cd, surface area, local pressure, local temperature, and air speed. As the above poster mentioned, high end sports cars generally have Cd numbers in the mid 0.3s. Motorcycles however have Cd numbers close to 1.0 depending on the model bike, size of rider, and riding position. In looking at the formula you should be able to deduce one major point. Drag is increasing exponentially with speed. Plugging in some generic numbers show this better. Variables: Standard atmosphere (sea level, 15 degree C, and a barometer of 29.92), Car at .35 Cd. Bike at 1.0 Cd. Car surface area at 19 sq. ft. Bike surface area at 7 sq. ft. (surface areas and Cds are approximate numbers). 50 kts Bike Dt = 59.32 lbs Car Dt = 56.35 lbs 100 kts: Bike Dt = 237.3 lbs Car Dt = 225.44 lbs 150 kts: Bike Dt = 533.90 lbs Car Dt = 507.20 lbs Conclusion: In the case of cars vs. bikes the bikes generally have triple the Cd but 1/3 the surface area so Dt remains about the same regardless of speed. Cars kick the crap out of bikes at high speeds because at high speeds the predominant factor is aerodynamics. As speeds increase the rate of acceleration decreases and the superior HP/weight ratio that gave the bike superior acceleration at low drag speeds cease to be the deciding factor. At high speeds where rates of acceleration are minimal you need horsepower to overcome the drag factors. As we have seen, aerodynamic drag is approximately equal so whoever has the most horsepower wins. | ||
| Boltrider |
Slaughter, I was hinting at the fact that modified Mustangs can run pretty close with a lot of street bikes, but the power-to-weight comparison is usually in favor of the bike. Yet they are close, so I figured it might be poor aero on the part of the bike. I came across that R1 link a little while back, but wanted to check with you guys. I couldn't find any links to an actual comparison between the 2. (Message edited by boltrider on December 29, 2008) (Message edited by boltrider on December 29, 2008) (Message edited by boltrider on December 29, 2008) | ||
| Cityxslicker |
the weak part of the equation is the exposed bumpy rider attached to the top of the bike. Your cross section is way less, but I dont know that your total coefficent of drag is less. And its all symantics really, a laser pointer radar will nail your a$$ for the ticked every time. DAMHIK | ||
| Ducbsa |
Bumpy rider is right. See  The story was that Rollie Free had borrowed a set of leathers from a bigger guy and they flapped a lot at speed, so he stripped down to his swim suit, gained a few mph, and made his record runs. | ||
| Spiderman |
cars will always be 'slicker' than bikes. | ||
| Blake |
"Total drag (in lbs) can be found by multiplying the Cd, dynamic pressure* (q), and the surface area (S). " Good grief, that is about as wrong as you can get. Leave it to the R1 forum to make up stuff about aerodynamics. Surface area?  There are two types of drag coefficients, one that is dimensionless and is a true coefficient CD, and one, CDA that is multiplied by the incident area (NOT surface area). Or something like that. The true measure of aerodynamic drag performance for any form of vehicle is the dimensionless coefficient. In that respect, the slippery automobiles blow away the slippery motorcycles by a wide margin. (Message edited by Blake on January 02, 2009) | ||
| Scott_in_nh |
Close Blake, what you are looking for is "frontal area". That is the cross area of the vehicle at it widest and tallest point. The true measure of aero efficiency of a shape is the drag coefficient, but the true measure of drag performance has to take into account the frontal area. A 1:24 scale model of a Corvette has the same drag coefficient as the 1:1 full size one, but would obviously be easier to push through the air. Also, the frontal area gets multiplied by the drag coefficient, not divided; Drag = A X Cd X V Squared / 410 where A is the frontal area of the vehicle, Cd is the coefficient of drag and V is the vehicle speed (MPH) and is squared in the equation. | ||
| J2blue |
Not to begin to approach the completeness of what has already been said...BUT...  Intuitively I can kind of get the idea of a modern "aerodynamic" car/truck having less drag, or better, less "non aerodynamicness". If one could magically stretch proportionately a motorcycle to match the same area as a car displaces, then I would think that the car would be much "slipperier".  I don't think the average rider would be able to touch the pavement with either foot, though. | ||
| Spiderman |
I already said all that and posted proof to back up my statement! Jeeze guys quit smartin it up! | ||
| Davegess |
To bring in a Buell, how does an RR1000 fit into this? It makes the rider part of the solution not part of the problem. | ||
| Scott_in_nh |
Someone, somewhere probably has a Cd number for the RR, but I am not going to venture a guess. While it is obvious from the speeds that bodywork has run that it is a good number for a bike, I would bet that the relatively short length still makes it difficult to keep a laminar airflow off the back of the bike. Turbulent air increases drag. | ||
| Scott_in_nh |
Based on the below you can see that the RR is probably little better than a poorly designed sedan, but I am sure it has less frontal area. Having a long streamlined shape with very little frontal area and a Cd probably in the 0.20's is how Burt got his Indian to 200 mph. http://www.ehayes.co.nz/burtmunro/ Air Drag Coefficients and Frontal Area Calculation The use of coefficient of drag and frontal area are common when determining horsepower requirements for vehicles in motion. One source of these figures are past issues of Car and Driver or Road and Track magazines. These values can also be determined using the following (obtained from "The ACCELERATOR Slide Rule"): Coefficient of Drag The aerodynamic "features" of a vehicle in motion are reflected in its drag coefficient values. Low coefficients indicate low air resistance. The following chart list some ranges for various vehicles, which will suffice when actual measured values are not available: Vehicle Drag Coefficient Description Low Medium High ---------------------------------------- Experimental 0.17 0.21 0.23 Sports 0.27 0.31 0.38 Performance 0.32 0.34 0.38 60's Muscle 0.38 0.44 0.50 Sedan 0.34 0.39 0.50 Motorcycle 0.50 0.90 1.00 Truck 0.60 0.90 1.00 Tractor-Trailer 0.60 0.77 1.20 Calculation of Frontal Area Frontal area represents the front projection area of the vehicle. If one takes a picture of a vehicle, it is the area included in the outline. Use the following to calculate: 1. Calculate the area of a rectangle which would encompass the front of the vehicle (multiply width by the height). For motorcycles, use the handlebar width (to a maximum width of 30 inches) and a height consisting of seat height plus an estimated "seat to helmet" height. 2. Adjust the figure obtained above for areas not included, such as top rounded corners, etc. Typical adjusting values are 85 percent for cars, 70 percent for motorcycles, and 100 percent for trucks. -------------------------------------------------- ------------------------------ Bruce Bowling http://www.bgsoflex.com/airdragchart.html (Message edited by scott_in_nh on December 31, 2008) | ||
| Boltrider |
Nice, that air-drag chart is what I was looking for. What's funny is that this vendor I was BS'ing with sells truck stuff on the side, but his primary job is owner/operator of a motorcycle shop. He should have known better than to mess with Badweb!!  At higher speeds, the bike starts losing the battle of total drag. (Message edited by boltrider on December 31, 2008) | ||
| Sethbuchbinder |
Vehicle Drag Coefficient Description Low Medium High ---------------------------------------- Experimental 0.17 0.21 0.23 Sports 0.27 0.31 0.38 Performance 0.32 0.34 0.38 60's Muscle 0.38 0.44 0.50 Sedan 0.34 0.39 0.50 Motorcycle 0.50 0.90 1.00 Truck 0.60 0.90 1.00 Tractor-Trailer 0.60 0.77 1.20 Bottle nose Dolphin 0.0036 Looks like the todays engineers have a long way to go to match mother natures numbers. I know its off topic but still puts things in perspective. Maybe the next Buell will be shaped like a Dolphin and be painted with a custom slippery shedding skin like that of the dolphin. Seth} | ||
| M2nc |
As people get the equations straight let me drag this into practical terms. There are two major variables in this equation that equals 'Drag Area', drag coefficient and frontal area. Example: A car with a .32 Cd and 25 sqft frontal area will have a Drag Area of 8 sqft. Da = Cd*Frontal Area or .32*25sqft = 8sqft Now lets compare this to a Bike. A modern sport bike should be in the .5 Cd range and a frontal area no larger than 5 sqft. Da = .5*5sqft = 2.5 sqft or three times smaller Drag area than the car example about. By the way these numbers are close to modern sport bikes and cars. A dolphin is slick in the water because of the pointy nose (very small frontal area). Race cars bottle in like the dolphin, so do airplanes. But the only four wheeled vehicle to have as small of a frontal area as a bike are race cars and carts (F1, Dragsters or Indy). So since most cars have much larger frontal areas than bikes, their lower drag coefficient only balances the contest. Or does it? Lets stop punching calculators and take this into the real world. Lets take a look at our Buells. An XB12 makes 103 crank horsepower and has top speed, gear limited, at 137mph. Some here have opened up the gearing and claim over 140mph top speed. How many cars with 103 crank horse power can reach 137mph? Not too many, in fact I can not name one. Now most of your V-6 Japanese sedans will out top end our Buells. Average top end speed is about 145mph but they have 2.5 times the horsepower or around 260 crank horsepower. So lets take a look at sports cars and sport bikes with about the same horsepower. Which is faster between a Miata (141hp)and an 1125R (146hp)? The 1125R is 25mph faster. (135mph versus 160mph.) Which is faster between a Lotus Elise SC (210hp) and a ZX-10R (180hp). Even limited the ZX-10R will be 30mph faster. (155mph versus 186mph governed) Which is faster between a 883 Sportster (65hp)and a Smart Car (70hp). The Sportser is 11mph faster. (106mph versus 95mph) Take a look at Cycle World -July 08- 0-180mph test. They brought a lot of stock bikes and all but the 1098S broke 180mph. Most hit the governor hard (ZX-10R 0-180mph in 17sec) meaning with it removed most stock liter bikes can do more than 190mph with 180 crank horse power. Again how many cars with 180 crank horse power can break 190mph. I can not think of one. Now take the modified car and bike in the same article. A Ford GT twin turbo-charged and boasting 1000 crank horsepower. With some mechanical difficulties the car topped out at 220mph. Hennessey claimed with the car functionally perfect it should hit 235mph. As for the Bike a turbo-charged GSX-R1300 boasting as much as 590rwhp. The bike has entered several 200+mph clubs and the owner claims the bike can do over 260mph. That is faster than the 1000hp Bugati Veyron. So why do modern super cars go faster than the fastest bikes. It is not because of a drag area advantage. It is because of more horsepower and a gentleman's agreement to limit top speed of bikes to 300kph. Happy New Year! | ||
| Anonymous |
Aerodynamics is definitely an area where there is a lot of mis-information. M2, your CdA comments are correct, but the numbers are not. You'd have a hard time finding a sport bike with a 0.5 Cd. But the small A is indeed what allows bikes to do pretty well. Also note that Cd is not a fixed number, but actually can vary with speed. For example, short vehicles with reasonable medium speed Cd's can go to heck at high speeds. | ||
| Ourdee |
Weird stuff from HPV racing. 2 fully faired human powered vehicles get out on a track and the 2nd vehicle tries to draft the first. The 1st vehicle will notice a speed increase and the second will experience increased drag.I sight this link for support-> http://www.recumbents.com/WISIL/demma/aero_review. htm Here is a couple of mine without full fairings http://www.recumbents.com/WISIL/stockinger/alley_c at.htm http://www.recumbents.com/WISIL/stockinger/ray_sto ckinger.htm Bike with naked boy in the pic above was a 1952 Vincent Black Lightning (my dream bike) went 150 mph in the early 50s and held record for factory stock till the 70s. I think it was taken by a Kaw 900 or 1000. The Vincent weighed about 300 lbs (used some magnesium) and was rated at about 100 hp. Link to more info-> http://www.motorcycledaily.com/15october02vincentmotors.html (Message edited by ourdee on January 01, 2009) | ||
| M2nc |
Anon - You may have more access to real numbers than I. It's tough finding actual drag coefficient on production motorcycles. What I do have is a reference from a book on motorcycle dynamics (yes I boogared up the equation designation and left out 1/2p air density and velocity squared for the sake of simplification.) This reference shows Drag Area in metric dimensions close to what I have above. The book stated a Super Bike at .3m² where I listed converted to metric is .23m². Suzuki states the GSX-R1300 .27m². So may be I over-estimated frontal area and under-estimated drag coefficient because I extrapolated the information from what I could find. From "Motorcycle Dynamics" CdA for motorcycles Speed Trials Bikes = .18m² MotoGP = .22m² Super Bike = .3 to .35m² Sport Bike w/ small fairing = .4 to .5m² Standard Bike with rider erect = .7m² Suzuki advertised this is their best production bike drag area when the bike first came out. GSX-R1300 of .27m² Compare that to the real numbers of cars which average around .8m². 2009 Nissan GT-R Super Car = .62m² I also found in the Knowledge Vault a CdA quote for the RR1000 of .25m². Impressive that a bike twenty years ago is still competitive aerodynamically with modern sport bikes. This may be due to form over function or trying to reduce lift at speed. Which leads me to this question, does the chin spoiler reduce frontal lift, or is it just decorative? | ||
| Blake |
Scott, "Close Blake, what you are looking for is "frontal area". That is the cross area of the vehicle at it widest and tallest point. " You sure about that? While "frontal area" is an accurate term to describe the area used in aerodynamic drag calculations, I'm not sure it matches your definition. I think the area that we are talking about is best described as that of the vehicle's projected silhouette taken from the direction of aerodynamic travel, not the area at any particular cross section. When speaking in terms of aerodynamic drag, what is the difference between "frontal" and "incident" areas? Professor? My prior post, since corrected thanks to you, did indeed include a mistake. In my haste to post, I mistakenly stated that the CDA coefficient is "divided by" the incident area; wrong. The CDA coefficient is multiplied by the reference--there's another drag area term for you, also accurate-- area, not divided. In short CDA = CD*A However, my statement concerned the CDA coefficient itself, not the procedure for calculating the drag force as you seem to have surmised. To clarify, my point was that there is a lot of confusion on account of there are two types of drag coefficients commonly reported for motor vehicles, and folks get them mixed up or don't know that there are two. One, CD is a true dimensionless drag coefficient, the other, CDA, includes the incident area of the vehicle. Unfortunately, some motor-journalists have taken to reporting, possibly repeating from the OEM, drag coefficients in the form of CDA. Thus the confusion by some thinking that sport motorcycles may offer more efficient aerodynamic forms than sport cars. If we are interested in comparing aerodynamic efficiency (efficiency of form), then only the true CD is applicable. If we just want to calculate the actual drag force, then we may use either coefficient; just don't multiply by the area if you use cDA; it's already in there. To calculate drag force using a CDA coefficient, one need only multiply by the dynamic pressure (Q) equal to VMPH2/391 for STP. Might want to check the "410" divisor in your drag force formula. For STP and with "V" in units of MPH, the divisor should be 391, or use a multiplier of 0.00256. Those are two numbers that have been firmly ingrained in my brain after more than a decade of calculating wind induced loads required for the structural analysis of earth station satellite antennas. Fun stuff. PS: STP ==>> "Standard Temperature & Pressure" | ||
| Scott_in_nh |
Hi Blake, yes this is interesting and fun stuff. Your experience with this stuff is much more recent then mine so excuse the "rust" on the subject. You sure about that? While "frontal area" is an accurate term to describe the area used in aerodynamic drag calculations, I'm not sure it matches your definition. I think the area that we are talking about is best described as that of the vehicle's projected silhouette taken from the direction of aerodynamic travel, not the area at any particular cross section. We are thinking the same thing, and they mean the same thing, but your explanation is easier to understand (thanks). When speaking in terms of aerodynamic drag, what is the difference between "frontal" and "incident" areas? I could be wrong here, but I think you are referring to what would be known in aviation as the "angle of incidence" where the frontal area changes depending on the relative angle of the shape vs the relative wind. I'm guessing - but maybe you used this number because your towers are angled from a wide base to a narrow peak? Since, at top speed anyway, cars and motorcycles only change their angle of incidence through aero lift - I think we can discount it for the purposes of this discussion. If we are interested in comparing aerodynamic efficiency (efficiency of form), then only the true CD is applicable. Obviously we agree on this, but I like the idea of a Cda as it is an aero number that can be used to more directly compare different sizes or types of actual vehicles not just their shape. For example -A full size SUV with a Cd of .40 is still going to use more energy to push the wind aside than a subcompact with a Cd of .50 because of the additional frontal area. Using Cda would indicate this while using the Cd would not and Cda is probably more inline with most folks understanding of aerodynamics. Might want to check the "410" divisor in your drag force formula. This is not a formula I have had much use for lately, so I relied on the web. I will look into it. Scott (Message edited by scott_in_nh on January 02, 2009) | ||
| M2nc |
I agree it is fun, I am learning a lot on the subject. But as Anon stated above, a motorcycle is not efficient through the air. That said a motorcycle's drag area (CdA) is smaller than a car because it is punching a smaller hole in the air. So drag effects it less than a comparable car (sport car to sport bike). Frontal area of a car can be changed without changing the overall largest cross section of the car. Look back to the early days of aerodynamics in NASCAR. Chrysler put a pointy nose on the front of a '69 Charger, form fitting swept back back-glass and tall rear spoiler. The nose and the back glass helped the Charger cut through the air cleaner because back-glass lowered it's drag (Cd) and the nose piece reduced its frontal area (A). In '69 and '70 (Superbird) this car with the exact same, frame, front fenders, doors and rear quarter panels won 47 of 53 races and was outlawed by Nascar in 1971. Frontal area is important because this area creates a pressure wave of air in front of the vehicle pushing against it slowing the vehicle. Drag coefficient states how much pull disturbed air around and behind the vehicles has on the vehicle slowing the vehicle. Look at two cars roughly the same size the Cadillac CTS vs Mazda 6. CTS W = 72.5" L = 191.6" H = 57.5" Its largest cross section is 28.95 sqft, but its Frontal Area (A) is only 24.6 sqft. Mazda 6 W = 72.4" L = 193.7" H = 57.9" Its largest cross section is 29.11 sqft, but its frontal area (A) is only 26.5 sqft. So you see the largest cross section is not frontal area and overall cross section though it will effect efficiency through the wind, does not necessarily dictate frontal area. Cadillac's overall cross section area is 99.5% the size of the Mazda, but the Cadillac's frontal area is only 92.8% the size. Now take shape into account. The Mazda though it has a larger frontal area has swept and curved shape and is very efficient through the air. The Cadillac with its smaller frontal area has a squared off shape and is not very efficient through the air. Cadillac CdA = Cd (0.36) * A (24.6 sqft) = 8.9 sqft. Mazda CdA = Cd (0.27) * A (26.5 sqft) - 7.2 sqft. In conclusion we have two vehicles with roughly (within 1%) the same largest cross sectional area. The Mazda has a larger frontal area, but because the Mazda is more efficient than the Cadillac on the sides and back of the vehicle, its drag area (CdA) is considerable smaller (80.8% of the Cadillac). | ||
| Jb2 |
Anon, Aerodynamics changing with speed is one of the things that is hard to calculate with a clean sheet and a unskinned bike. I was talking to Aaron Wilson in September and he relayed some information that tweaked my interest. Someone had done some tunnel testing with bare or standard bikes. They found out that at speeds of over 100mph a large headlight had positive effects on the bike. He had put large diameter headlamps on all the unskinned bikes they ran this year. The RR1000 had this base pretty well covered with it's unusually large frontal surface area. JB2 | ||
| Blake |
What you need is a REALLY large headlight that also has a nice aerodynamically shaped conformal lense cover. | ||
| Jb2 |
Blake, Actually most round headlamps are convex pre-curved from the factory. The large diameter ones almost match the round shape of the RR race fairing(without headlamp). The flat square ones fairly suck at aerodynamic slipperiness. JB2 | ||
| Blake |
I never ever liked rectangular headlamps. Now all the S2/S3 owners are gonna come after me, so I'll go hide. Hey JB, I just uncovered one of my many piles of stuff and found your calendar still unopened. NICE work! And Thank you! January, September, and October are my favorites. Dave Barr, nuff said! Cumberland bridge and '65 FLH, nuff said! The inadvertent juxtaposition of the old panhead and the new computerized fuel pump is actually wonderful, genius really. | ||
| Scott_in_nh |
Frontal area of a car can be changed without changing the overall largest cross section of the car. Look back to the early days of aerodynamics in NASCAR. Chrysler put a pointy nose on the front of a '69 Charger, form fitting swept back back-glass and tall rear spoiler. The nose and the back glass helped the Charger cut through the air cleaner because back-glass lowered it's drag (Cd) and the nose piece reduced its frontal area (A). In '69 and '70 (Superbird) this car with the exact same, frame, front fenders, doors and rear quarter panels won 47 of 53 races and was outlawed by Nascar in 1971. Carlos the way you are calculating cross section gets a pretty close estimation of frontal area, but cars aren't boxes and some frontal area is lost to the curves. That should be enough variation for the numbers you posted. Dodge lowered the Cd with the Daytona, but actually increased the frontal area with the wing above the roofline and the front spoiler. You do not change frontal area unless you change the profile (as Blake described it) regardless of changes to the shape; A 1' diameter rocket, without stabilizing fins, would have about 3.14 square feet of frontal area. This would still be true whether it was blunt or pointed or 10' long or 100' long. If you take a photograph from the front or back of the vehicle at exactly the same angle as the wind sees it and blacken the picture everywhere that you can see the vehicle - the blacked out area is the frontal area. Flushing out the back window helped keep the flow laminar. The turbulent air that was there created drag. The front end obviously creates less drag over the standard blunt nose. | ||
| Jb2 |
Blake, Thanks. January and May have been sentimental favs of a few folks. For the "in the moment" you can't beat October. I like the old squares and no offense taken. If I were to own another Buell it would be an S2. One of the best bikes I've ever owned. ------------------------------------------- Regarding the thread... One thought; regardless of how best to make a motorcycle aerodynamic or if it could ever be better than a car matters not. How could you ever replace the experience of riding with a car? A bike will always be better! Cars suck! JB2 | ||
| Boltrider |
A bike will always be better! Cars suck Agreed!! | ||
| M2nc |
JB so true. Scott - You are right except one thing. I was perplexed with the numbers which are manufacturer's specifications. Then I found my missing puzzle piece reading an article from a NHRA crew chief. The height listed above is from the ground, not from the bottom of the car. So that explains the different frontal area. It also explain the Daytona Charger because they lowered the car. This is the same thing listed in the article I read which made me realize the numbers above. By lowering the car they reduce exposed tires and other bits and reduce drag under the car. Another way to reduce frontal area is to have skinnier tires or smaller mirrors. These threads are cool. They make you think. One thing I noticed researching this topic is that there was a lot of information about aerodynamics of motorcycles from 1980 to about 2000, then it drops off. I wonder how much this information trend follows fashion trends. In the 1980s the fashion trend was sport bikes with fairings. Today the latest liter bikes have less fairings almost following Buell's example with the 1125R. Is the lack of interest in faired bikes reducing study and discussion? Or is it just me? | ||
| Scott_in_nh |
Blake the 410 used in my calculation comes from a site that specifically references Bonneville. While they do not say so, I would have to surmise (fancy word for educated guess since I am to lazy tonight to dig into the math further ) that it represents the correct STP for Bonneville's 4320' elevation. Carlos, that makes sense. | ||
| Blake |
Scott, That seems plausible, but when you look at the numbers it still doesn't add up. My Mechanics of Fluids text by Dr. Irving H. Shames indicates (interpolating between values given for 4000' and 5000') that air density for standard pressure and temperature at a 4320' altitude should be about 88% of that for sea level, so the divisor factor should be around 444, and that is for the standard temperature at that altitude, which is about 43.6oF. At a more plausible 70oF ambient temperature for a Summertime Bonneville event, ratioing the absolute temperatures increases the divisor factor another 5.2%, [(459.67+70)/(459.67+43.6)]=1.052, to 467. Maybe humidity is playing enough of a factor to render the ideal gas assumption inaccurate? |
