Petervs
01-22-2007, 08:32 PM
OK, nobody should be surprised that there is ONE error on this site that is otherwise filled with tons and tons of good factual information.
On the Home Page there is a list of articles, one of which is called "High Altitude Touring". It says, "
Now for the bus: Here are some facts that most of us may have forgotten over the years, but are important: At sea level, the atmospheric pressure is 14.7 pounds per square inch. At 6,000 feet in altitude, the atmospheric pressure is 6.85 pounds per square inch."
This is completely incorrect. At sea level standard atmospheric pressure is 14.7 psi. But at 6000 feet the standard pressure is 11.87 psi.
The pressure varies a little bit with the weather, a few tenths of one psi perhaps, but it would never get as low as 6.85 psi as stated.
Also, they discuss the boiling point of water at 6000 feet, it says it is 175.8 degrees F; it is actuually 201.1 degrees F .
So really, the point I am making is that the effects described in the article are true, but the numbers provided exaggerate the amount of difference you can expect. One additional thought, the bus experiences what pilots refer to as Density Altitude. This is the apparent altitude corrected for temperature and humidity. If you are at 6000 feet on a standard day, the temperature would be 35 degrees there. But on a hot summer day, say 80 degrees F, the density altitude would be 9138 feet. So the engine on the bus "thinks" it is driving at 9138 feet. That affects cooling systems, etc. The turbocharger continues to pump in enough air to let the combustion process occur just like at sea level as long as the rpm is up enough.
Since we do not know who wrote this article, we have no way to know how much faith to put in the information presented. I am certain his intentions were good, perhaps there was some confusion in units of measurement or something. Feet and meters or degrees F and C?
OK, so on the other thread ( POG code of ethics) I was promoting the idea that we rate the post 2 ways; the person posting can rate himself AND everybody else can rate the post as written. We need to do this because how else do you know who is who, who knows his stuff, who is full of beans? Since we are using fake names ( some are anyway), and not everyone has met everyone, we need to add some credentials to help guide the information flow. Just like on eBay, where feedback is left for buyers and sellers, it gives a way to sort the wheat from the chaff.
And by the way Mr. Win42, you can not close out the Code of Ethics thread just because you don't want to deal with it any more! Go stand in the corner for 5 minutes and reflect on your bad behavior!
Peter VS
94 Marathon XLV
On the Home Page there is a list of articles, one of which is called "High Altitude Touring". It says, "
Now for the bus: Here are some facts that most of us may have forgotten over the years, but are important: At sea level, the atmospheric pressure is 14.7 pounds per square inch. At 6,000 feet in altitude, the atmospheric pressure is 6.85 pounds per square inch."
This is completely incorrect. At sea level standard atmospheric pressure is 14.7 psi. But at 6000 feet the standard pressure is 11.87 psi.
The pressure varies a little bit with the weather, a few tenths of one psi perhaps, but it would never get as low as 6.85 psi as stated.
Also, they discuss the boiling point of water at 6000 feet, it says it is 175.8 degrees F; it is actuually 201.1 degrees F .
So really, the point I am making is that the effects described in the article are true, but the numbers provided exaggerate the amount of difference you can expect. One additional thought, the bus experiences what pilots refer to as Density Altitude. This is the apparent altitude corrected for temperature and humidity. If you are at 6000 feet on a standard day, the temperature would be 35 degrees there. But on a hot summer day, say 80 degrees F, the density altitude would be 9138 feet. So the engine on the bus "thinks" it is driving at 9138 feet. That affects cooling systems, etc. The turbocharger continues to pump in enough air to let the combustion process occur just like at sea level as long as the rpm is up enough.
Since we do not know who wrote this article, we have no way to know how much faith to put in the information presented. I am certain his intentions were good, perhaps there was some confusion in units of measurement or something. Feet and meters or degrees F and C?
OK, so on the other thread ( POG code of ethics) I was promoting the idea that we rate the post 2 ways; the person posting can rate himself AND everybody else can rate the post as written. We need to do this because how else do you know who is who, who knows his stuff, who is full of beans? Since we are using fake names ( some are anyway), and not everyone has met everyone, we need to add some credentials to help guide the information flow. Just like on eBay, where feedback is left for buyers and sellers, it gives a way to sort the wheat from the chaff.
And by the way Mr. Win42, you can not close out the Code of Ethics thread just because you don't want to deal with it any more! Go stand in the corner for 5 minutes and reflect on your bad behavior!
Peter VS
94 Marathon XLV