Steve Andrews
New Member
And I really hope he is right! I posted this blog entry about it: http://bardofelysays.blogspot.com.es/2012/06/is-chemtrail-era-about-to-end-jazzroc.html
Another reason why I have doubts is that humidity or even relative humidity has no appreciable bearing on the performance of a jet. Hence it is not measured on the aircraft and a good reason would have to be put forward to install such equipment.
Hmmm, unless contrails can be shown to have severe negative consequences, why would I re-route hundreds of miles around humid air?
Another reason why I have doubts is that humidity or even relative humidity has no appreciable bearing on the performance of a jet. Hence it is not measured on the aircraft and a good reason would have to be put forward to install such equipment.
Correct, it has no real effect.
And I really hope he is right! I posted this blog entry about it: http://bardofelysays.blogspot.com.es/2012/06/is-chemtrail-era-about-to-end-jazzroc.html
Wouldn't it be nice if there were an easy way to slash global carbon emissions by more than 40m tonnes each year? That's a serious saving – about as much as the entire Danish economy.
What if the total impact on combatting climate change was twice as much as that figure suggests, because all that carbon would have been emitted – along with a cocktail of other pollutants – at high altitude? And what if the plan would also save huge amounts of time and money?
If that sounds too good to be true, then you probably have't met David Parkinson, the inventor and engineer on a one-man mission to drag air-traffic control (ATC) into the digital era. Parkinson believes that using computers to calculate perfectly smooth trajectories for planes could painlessly cut 8% of aviation emissions.
Humidity affects the way an airplane flies because of the change in pressure that accompanies changes in humidity. As the humidity goes up, the air pressure for a given volume of air goes down. This means the wings have fewer air molecules to affect as they are pushed through the airmass. Fewer molecules = less lift.
The other problem is that jet engines do not like humidity either. Jet engines are built for cold, dry air, and humid air has fewer oxygen molecules to burn per unit volume. Therefore the engine combusts a little bit less and puts out slightly less thrust. There are four factors that decrease the performance of a jet airplane - heavy, hot, high, and humid. Notice that three of those factors all have the net effect of lowering the density of the air.
So there you have it. Humidity decreases the performance of most aircraft, not only because of it's effect on the wings, but also the effect on the engines.
With the effect being so small that no-one has ever noticed the difference.
No one has ever noticed ?
Type "humidity effect on aircraft performance" into Google and take a quick look through a few of the 300,000+ results . . . . oddly counter to your notion people do seem to have noticed the effect of humidity effect on aircraft performance.
In fact the general tone seems to be that the effect is 'significant', 'pronounced' and/or 'dramatic'.
You might want to share your ideas with the engineers who build longer runways in humid climates.
Humidity also plays a part in this scenario. Although it is not a major factor in computing density altitude, high humidity has an effect on engine power. The high level of water vapor in the air reduces the amount of air available for combustion and results in an enriched mixture and reduced power.
When they say the effect is significant, they're lumping humidity together with temperature and pressure. Density Altitude, something all pilots know about, is based on temperature and pressure, humidity is not even a variable in the formula used to calculate DA. Humidity does have an effect on reducing engine performance because water vapor displaces some of the air but water vapor is at most only 4% of the atmosphere by volume so even in the worst case scenario it only reduces horsepower by a few percent. Airplanes routinely fly through rain after all and they seem to do just fine. Humidity is really only a factor when the aircraft is near it's max. takeoff weight. I think the main reason for longer runways in humid climates is because those climates are also generally hot, and heat is the primary factor in dramatically reducing lift so the plane needs more time to build up more speed before it can takeoff.
You might want to share your ideas with the engineers who build longer runways in humid climates.
When they say the effect is significant, they're lumping humidity together with temperature and pressure.