Stators cause loss of energy as well. They have drag.

Paul Lamar ...No rotor no motor.

Drag yes, but with a net gain over not using them! I figured Gordon was
headed here. The Tu-95 Bear seemed retro back in the mid-50s when the
U.S. was deploying B-52's and playing with B-58's. Not so much laughter
after we figured out it could hit 500kts (over .8 mach), carry a
25,000lb payload almost 4,000 miles unrefueled--less than half the
payload of a Buff, but almost the same range--and they could build
something like ten of them for the same price. Nightmares of herds of
these things coming over the horizon helped inspire the Genie missile, a
1.5 kiloton nuke for lobbing into formations of bombers, which was the
only way an F-106 driver was going to do anything about it.

Since we already have a gearbox, what would it take to turn two props
with it? Paul, you say ducts suck below 400mph. I LIKE going 400mph. Are
we content to quit just because we can outrun a 172?! Tell me why with a
four-rotor rotary we can't hit 500? It sounded like you went along with
Matt panning the duct idea, because a turbofan will outperform it at
40,000ft. Let's not throw the baby out with the bath water here! Have
you priced your favorite turbofan candidate?

Nobody but US has lifted a finger to give US anything better than a
Lycoming in the last 70 years. With 1/10 the money spent going to the
moon invested in R&D back then, I'd be cruising around by now at .85
mach or so using something like a little ceramic turbine the size of a
coffee thermos. There was a big deal about non-afterburning supercruise,
trying to sell Congress F-22's. So when the shiny new F-16C/D's arrived,
the idea sunk in without anyone actually saying it, not to rock the
funding boat by advertising that you could overspeed a load of bombs
(mach 1) with it at Mil power.

That's a ducted fan, with no fancy inlet devices past the boundary layer
lip, and a goofy air path to get the bypass air back into the burner can
and out the nozzle. What that means to us, is that we can get an
airframe nearly transonic, while keeping things subsonic in the tube
through the fan, which is where the counter-rotator canceling the twirl
seriously starts to whup a conventional prop, because you can pressurize
a tube. Outside the tube, conventional prop tips are supersonic at that
speed. Inside the tube, the fan is subsonic, yet you get supersonic
thrust at the nozzle. Now are you guys going to tell me, off the cuff,
that there is no point in dusting off our slide rules to see if we can't
slip some sexy fiberglass thing into a sweet spot somewhere around .8,
with the weight / hp / fuel consumption / circumference (flat-plate) /
price point numbers of an aluminum four-rotor rotary?

</RANT>

Donald Willard Garrett


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