"Chad Irby" wrote in message
m...
In article ,
(The Enlightenment) wrote:

Chad Irby wrote in message
.. .
In article ,
(robert arndt) wrote:

http://www.luft46.com/misc/wes1003.html

"Although this was a very novel idea for an aircraft at this
time, the
concept never left the drawing board."

1/15 the loaded weight of the Osprey, some very optimistic
numbers (400
MPH? Yeah, Right.), and no grasp of the difficulties in gearing
and
power issues in a tilt-wing aircraft.

So you say they had "no grasp". They had built and put into naval
service in 1943 the Fletner Fl 282 Kolibri (hummingbird)
intermeshing
rotor helicopter which was entirely succesfull despite the
technology
of gearbox designe.

So you're comparing a small helicopter with two fixed rotors and a
simple fixed gearbox with a full-up tiltwing aircraft?

In hovering fligh it has the same control configuration as a tilt
rotor in hovering flight.


The only thing that prevented the production run of 70 extending
to
1000 was allied bombing.
http://www.centennialofflight.gov/es...ettner/HE6.htm

Still, comparing a simple little helo to a tiltrotor.

That's funny.


Not at all. The controlability issues of hovering flight had been
solved.

What remains is lighter transmissions and powerplants and the problem
of transition from hovering to horizontal flight.



They had flown and tested the Focke Achgelis Fa-223 Drache which
has
the same configuration in vertical flight of the V22 and P.1003.

http://www.centennialofflight.gov/es...a_223/DI52.htm

You might note that the FA-223 was a twin-rotor *helicopter*, not a
tiltrotor. Besides having the rotors out on booms at the sides, it
was
not really very complicated (and slow, due to the massively
increased
drag of those two side booms).

Now encase the booms inside wings that can tilt.


Once again, nothing like a tiltrotor, and nothing in these designs
would
have prepared them for the problems inherent in tiltrotor flight.
And
it *sure* wouldn't have let them build a 400 MPH tiltrotor right off
the
bat.

The small wings of tilt totors reduces drag considerably and helps
speed. Not having the propeller wash flowing over the fueselage also
helps. Lets assume they were wrong. Would you accept 330mph?
300mph?

Just an aside. When the XV-15 prototype for the XV-22 osprey was
built is was powered by the Allison T-53 (same as the huey). That
engine was designed by Franz Anselm, the same guy that designed the
jumo 004B for the Me 262 of WW2.

Anselm also designed the engine for the M1 Abrams tank.



The Nazis had a lot of Really Cool Ideas that would have never
worked (like the Sanger "America Bomber," which would have
melted
quite nicely the first time they did a reentry).

How do you know? The aircraft never re-entered at full orbital
velocity, it skipped at sub orbital velocities to reach the
required
range, take opportunity of cooling effects and a lower speed of
re-entry.

Actually, skip-reentry relies on a somewhat higher initial reentry
speed, as compared to the "plunge" method, and while max temps can
be
higher, the plunge method has some advantages. Note also that the
"skip" method relies heavily on radiative heat emission, and that's
not
very effective for dumping large amounts of heat in a short period
of
time.

Indeed but thats not a problem for winged re-entry vehicles that
unlike blunt bodies can fly and control their rate of entry hopefully
limiting the rate of hest buildup to that which can be radiated.


You still need some very high-temp metals (Inconel or titanium,
to start), instead of the normal stainless steel Sanger proposed.


Sangers aircraft the 'silver bird' was made of the high chrome steel
(stainless basically as used in the XB70 ) and I expect similar to
what was used in Boiler Tubes at the time. That can opperate at 600C
without loosing strength and beyond at reduced strength. Stainless
is more heat resistant than titanium and but less than inconel.


Even the X-15, which wasn't anywhere near as ambitious as the
Silverbird, had to have sprayed-on ablative coatings to hit high
Mach.
The only reason the Dynasoar project went as far as it did was
because
of the development work on the X-15.

Sanger never actually worked on the thermodynamic aspect of the
Silverbird, and that would have been a potential showstopper for the
program, even if he'd had more time to work on it. The plane was a
concept/mockup only, and very little actual engineering work had
been
done when the war came to an end.

Sure, sanger didn't know that blunt bodies provide some thermal
protection.

Here is the Sanger Thermal protection system.

The Sanger silver bird is stainless steel. Pilot and critical
components such as tires, control and crew cabin are insulted from the
over 600C heat of re-entry for as long as necesaary.

This is how I think it would have been tested:
1 The vehicle is run down its sled at mach 0.5, then mach 0.9 and
finaly mach 1.05 and mach 1.3.

2 Seperation tests from the sled are then performed with the vehicle
landing without powering up.

3 The vehicle is then powered up and aerodynamic and thermal
protection data is accumulated at progesssively higher speeds.

3 Sanger can land like a plane and it can carry a standard german test
pilot heinkel ejection seat for test pilot safety. This speeds up
testing becuase the vehicle is recoverable.

4 At some point they probably find hot spots than need better thermal
protection.

5 At that point they either have a technical fix (grapahite, high
nickel steels) or cooling systems (water or helium refrigerator like
the dyna soar)

The wedge shapped wing profile shows a keen understanding of
supersonic aerodynamics.

No, it just showed a basic understanding of high-speed flight.
Small
wings = high wing loading = higher speeds and lower maneuverability.
Landing speeds would have been high, even when empty.

It had a flat body to help both hypersonic re entry and landing and
braking parachutes.

If you look at the wings they are like triangular wedges like a
Sparrow missile.



The Germans had solved the hypersonic and heat shielding re-entry
problems of the V2

...by not flying it at high hypersonic speeds for very long. The
V-2
topped out at about 3500 MPH on reentry, and only managed that for a
very short time, in uncontrolled ballistic flight.

They had a heat shield. Graphite and plywood that turned to graphite.
No doubt other materials were in development. Eg dibule walled skins,
ablatives etc.
They had a problem defined and thus they could set about solving it.



Nothing like the 13,000 MPH the Sanger was supposed to hit.

Maybe Sanger would only have handeled a lower speed. say Mach 6 or
mach 10 instead of Mach 20. Sanger MkII on the otherhand?