Chemtrail mystery does air temperature matter

a reply to: F4guy

It still happens with the TF33 just not as bad.

originally posted by: Zaphod58
a reply to: F4guy

It still happens with the TF33 just not as bad.

Yeah, I understand Pratt wants to upgrade the 33 and keep it on the BUFF until 2040. My experience with the TF-33 is actually with the civilian version - JT3D - on some pre-reengined UPS DC-8s, a 187 foot long mailing tube with wings. It was scary to open the cockpit door and see the fuselage flex in turbulence. The flight engineer position actually had mechanical levers to open and close fuel valves. We did a Newark-Cologne turn with them. Later they added a Stansted stop.

a reply to: F4guy

Heat energy is heat energy, it isn't kinetic energy. As you correctly pointed out there's a finite amount of energy in fuel. The more efficient an engine is the better it is at converting that chemical energy into kinetic without wasting it as heat or sound etc

a reply to: F4guy

I disagree. Or maybe we are just saying but the same thing but from different sides.

The contrail factor is directly proportional to the propulsion efficiency. And greater propulsion efficiency will necessarily result in more of the chemical energy in the fuel being converted into useful kinetic energy, and less being exhausted as waste heat.

The upshot is that the exhaust of a more efficient engine is cooler, and so it will be more prone to condensing before it gets mixed out into the surrounding air. The observed contrail factors of engines with different bypass ratios (and hence different efficiencies) back this up.

a reply to: F4guy

They've already more or less said that's not happening. They're going to do a 1-1 replacement with similar engines. That gets the best bang for the buck.