your 1900 rpm is at the center an 9 in, out from center not the tip. what i been saying all along. just like on those wind generator i mentionedblades at center, speed 3 to 4 rpm. the tip speed is,

read power controll:

Power control[edit]

A wind turbine is designed to produce a maximum of power at wide spectrum of wind speeds. All wind turbines are designed for a maximum wind speed, called the survival speed, above which they do not survive. The survival speed of commercial wind turbines is in the range of 40 m/s (144 km/h, 89 MPH) to 72 m/s (259 km/h, 161 MPH). The most common survival speed is 60 m/s (216 km/h, 134 MPH). The wind turbines have three modes of operation:

this easier?

http://en.wikipedia.org/wiki/Wind_turbine_design

It is vapor. If you blow this up you can see trailing vapor coming off the tail, looks like a rope hanging behind the plane. If you want to see some more caused by speed, Google "Prandtl-Glauert singularity".
This is caused by speed and results when there is a pressure change, but the vapor has to be in the air to get this.
https://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&biw=1173&bih=569&oq=%22Prandtl-Glauert+singularity%22.+&gs_l=img.12...289790.293182.1.295329.1.1.0.0.0.0.109.109.0j1.1.0....0...1ac.1j2.29.img..2.15.638.-DuuU1OcbrI&q=%22Prandtl-Glauert%20singularity%22.

The original issue was about prop tip speed and how it was close to or faster than Mach 1. Never.
Where did that baloney come about a Stearman and the T-6?

OK if the radius of the prop is 40", then the circumference is 40x3.14=125.6 inches.

So if the rpm is 1900, then in one minute, the tip travels 1900x125.6=238640 inches or 19,886 feet. About 3.7 miles.


To convert ft/min to MPH, multiply the ft/min by .0114 = 226 mph.

Mach 1 at sea level with a standard atmosphere is 761 mph.

You guys need to stick to mis-information about cameras and leave the aviation stuff alone. :-)

Not too good at math, either.

Nest subject: Retreating Blade Stall. ;-)