Counter-rotating propellers sparked my curiosity when I first saw them on a British Seafire Mk46 at a flight show in the early nineties.

So my amateur's answer would be that it's about the problem of turning the engine's power into thrust. With increasing power, you can either increase the propeller's RPM or its area. So you either a) spin it faster, b) increase its diameter, c) use a more favourable blade geometry, d) add more blades.

a) and b) both lead to blade tips moving faster, and once they approach the speed of sound, wave drag sets in and ruins your day. b) also runs into issues in terms of ground clearance. Thus the Kim Jong-un blades on planes like the An-70: short and fat.

c) is rather difficult to do in terms of manufacture -- that's why more pronounced blade shapes are a relatively recent development.

d) on a single propeller decreases the efficiency of each blade as it passes through the previous blade's vortex. That's why, for instance, German planes in WW2 almost exclusively relied on 3-bladed propellers with increasing blade size, whereas Supermarine went to four and even 5 blades rather quickly. You can work the issue to a certain degree by modifying the blade geometry, thus the 8 blade props on a modern A400M.

Adding more blades by adding another propeller gets around d), although the aft prop still loses efficiency compared to the front prop. On the other hand, counter-rotating props massively reduces problems with torque, which can be rather horrendous for single engine prop planes. The Bf 109, for instance, is (in)famous for being difficult during take-off as it pulls to the side quite violently.

Okay, so you put half the population in a box so you don't have to deal with the concept that there were many other reasons people might have voted for Trump...

You get the irony right? Or is it left? He did say that this strategy wasn't exclusive the province of the right... /giggle

Saudi Arabia apparently holds the Prime Minister of a sovereign nation hostage: link

Quick, let's sell them more weapons for their upcoming war against Lebanon. Maybe we'll even get the hot war against Iran we've been craving for more than a decade.

Blocked has to do exclusively with it being unavailable to watch in a particular regions/countries of the world when available in others. So notblocked, however if a video is dead (not watchable on the sift) it's kind of a moot point.

You mean Americans like the one you pretend to be?
Those in power who stop (partial) solutions from becoming law are mostly (not exclusively, but nearly) Republicans.
Those who propose those solutions are exclusively non-Republicans, current bipartisan bump stock legislation being the single exception to that rule.

While non of these things are remotely good things, none of this is mind blowing. I think just about everyone who uses Google knows these things but chooses to ignore it.
Also, are you using Chrome? Then you give them exclusive access to everything you do on the web, not just through google search, because Chrome IS Google.

Hmmmm...but it's pretty exclusively a right wing position that ANY regulation on firearms is inconceivable, and Republicans exclusively are responsible for those modifications, like bump stocks, something he used to make at least one gun rapid fire, being legal. They also allowed the assault weapons ban to expire, allowing him to legally purchase up to 40 easily converted military style rifles. In fact, they were about to make silencers much easier to get, which would have increased the mayhem by giving him longer to shoot before people realized what was happening, but held back because of the massacre.

....soooooo...you do have to defend the availability of automatic guns, because you vote for and support the people that keep them easily available and want to make it easier....assuming you aren't really Dimitri from Moscow.

Not much known about him yet, not political, not religious, just a rich retired gambler according to his family.

Your video, It Came from the Desert (2017) Exclusive Teaser Trailer, has made it into the Top 15 New Videos listing. Congratulations on your achievement. For your contribution you have been awarded 1 Power Point.

Simply put: he doesn't get it.

"Divisive" is general and ambiguous. "Inclusive" vs "Exclusive" is the distinction he misses. It's a choice, (expletive)!

The confederate flag is being removed because it represents a deep seated division of the nation and culture and an exclusion of non-whites from humanity.
The LGTB/rainbow flag represents inclusion, and a rejection of divisive and exclusionary (and deeply held) "values" that, contrary to the most important teaching of their religion (the golden rule), allow some to force their narrow puritanical ideas about sexuality on others by force.
Total false equivalency.

Also going to take it out of general circulation (off the front page) and send it to sift talk till removed. *discuss

"The presence of human fatality is acceptable and not considered "snuff" if presented as a limited, incidental portion of a lengthy educational, informative news report or documentary that encompasses a much broader narrative. Our definition of "snuff" does include but is not exclusive to any short clip in which a human fatality occurs whether or not any victims are actually visible on camera."

It would be interesting if puddles continues the show as an actual contestant, but then at the same time not surprising? Yes he has his youtube following, and he has his own performances, but he doesn't have any contracts, no endorsements, he isn't exactly making mad bucks. He may not even have an agent. Around 2010 he was the lead singer in a band called kingsized which seemed to exclusively be an entertainment crew that does covers of older songs. For now it seems the band is defunct.

My guess is during the app process, established musicians can skip the first round (musicless singing) and go right to the public performance round. And puddles is doing this so he CAN get more exposure and help nail a music contract. Saddly I prefer puddle's covers over any original content. Some of us have songs that they really like and would prefer just to hear different versions of it.

Reuters headline: Exclusive: Trump campaign had at least 18 undisclosed contacts with Russians: sources

... and then the content:
"The people who described the contacts to Reuters said they had seen no evidence of wrongdoing or collusion between the campaign and Russia in the communications reviewed so far."

"Those discussions focused on mending U.S.-Russian economic relations strained by sanctions imposed on Moscow, cooperating in fighting Islamic State in Syria and containing a more assertive China, the sources said."

Then there's the cover of Time.

I have no idea if the media's quest to defenestrate Trump will be successful, putting avowed theocrat Mike Pence on the throne, but this I believe: it will destroy the last bit of credibility the media had left. All the hyperventilation without ever putting up anything conclusive is suicide in slow-motion.

For eight months now, they've been running the hacking story, which went from hacking to influencing to meddling. Not once have they produced evidence, neither the media nor the intelligence agencies, yet they keep on insisting it's the real deal.