WeserFlug P.1003 Compared to V-22 Osprey

Chad Irby wrote in message . com...
In article ,
"The Enlightenment" wrote:

"Chad Irby" wrote in message
m...

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.

Nope. Velocity is velocity, and coming in out of vacuum means those
steel wings are just little flanges out in the Mach-20 airflow waiting
to be melted - or broken off altogether.

Nope. There is someting called a hypersonic L/D (lift to drag ratio).

You can fly in and limit you rate of decent in a winged or lifting
body thus limiting peak heat to the extent that ablatives or even
tiles can be dispensed with.




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.

So the Silverbird could have managed about Mach 3 for a short period of
time, about 1/5 of the *necessary* speed for suborbital missions like
the one it was designed for... and then would have had to be scrapped
due to overheating of the structure.

It could have managed more than mach 3 easily. The vehicle could have
achieved sub orbital velocity at 13,000 mph. Re-entered and slowed to
a slower speed say 8,000 mph and skipped to cool of and so on.



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.

Insulation of the insides isn't the problem. It's the skin melting off
in a very short period that's the issue, combined with the lack of time
to re-radiate the heat before hitting the atmosphere again. When a
spacecraft hits the atmosphere at Mach 20, the temps reach 9500 degrees.

At a "mere" Mach 6, the X-15 skin reached 650 to 700 degrees C, in a
minute and a half of powered flight. This would have happened to the
Sanger several times per mission, with a skin that didn't have the heat
resistance of the X-15's.

Sanger is also higher up in thinner atmosphere. It skips up and down
and was actualy to cruise at more like mach 10.




This is how I think it would have been tested:

(Magical handwaving imaginary ten year test program deleted)

...you also left out the two or three Silverbirds that would have been
lost due to the control problems inherent in supersonic flight. And
then the one or two they would have lost due to the skin peeling off.
And then one or two due to not knowing about how to support a man in
space...

The vehicle had an all moving tail.

Either way Sanger was using the first hypersonic wind tunnel in the
world to test his model.




...if the program had ever gotten that far.

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.

...and would have come in at 200 MPH or so, like the Shuttle. So add
"develop high speed high load tires" to your development program. And
"redesign aircraft to really handle hypersonic flight."

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

Um, no. They're closer to the F-104 in shape and cross-section in every
image I've seen of the Silverbird. Much like the X-15 wings, as a
matter of fact.

They are triangular wedges. Look closer.



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.

...for the minute or two it took to reenter and impact.

No doubt other materials were in development. Eg double walled skins,
ablatives etc.

Replace "were" with would have to be once they started actually thinking
about it."

They were thinking about it. They apparently had a ceramics heat
shield program (for Sanger at least it appear) and more than one
hypersonic wind tunnel working on problems.



They had a problem defined and thus they could set about solving it.

...in several years. Which they didn't have, and had *not* anticipated
in the original idea.

Just about everying was anticipated, heat shielding included.



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.

...and been unable to complete its mission, which relied on long periods
of coasting in between moderate periods of slamming into the atmosphere
at 8,000 to 12,000 MPH and melting that stainless steel skin right off.

Then having to be redesigned for massive amounts of fuel to make up for
not being able to handle the original mission profile.

Getting enough velocity was not the problem. The engines were up to
it. A speed of 13000mph is less than 1/2 the energy required to reach
17,000.

The biggest problem is heat shielding. Sanger had a hypersonic wind
tunnel to test hypersonic L/D. Controll surface effects, stability
and propably even heat build up issues could be tested.



And a ten-year nuclear program to make a nuke small enough to carry in
the darned thing...

Off topic but The Germans had 25kg of enriched uranium in 1943, more
than the allies. They had developed supersonic centrifuges which is
the modern prefered method of enrichment. No huge gaseous diffusion
plants.



Sanger MkII on the otherhand?

Sure, and when they got the Ark of the Convenant out of that secret
American storage facility, they would have been unbeatable.

"The Enlightenment" wrote in message
om...


Off topic but The Germans had 25kg of enriched uranium in 1943, more
than the allies. They had developed supersonic centrifuges which is
the modern prefered method of enrichment. No huge gaseous diffusion
plants.


Bull****

The Germans only managed to enrich uranium to around 3.7%
and that only in small laboratory quantities.
They had a centrifuge program which FAILED miserably as did the
rest of their nuclear program. Given that the resources allocated were
extremely modest this is hardly surprising.

The major reason for their failure was the lack of materials
that could cope with the extremely corrosive Uranium Hexafluoride
the enrichment process required. With Germany critically
short of chrome, nickel and other allies the high strength
stainless steel alloys required were simply not available.

In December 1942 Dr Erich Bagge noted in his diary

"Conference in the rooms of the president of the
National Bureau of Standards, State Councilor
Esau. Diebner, Basche, Clusius, Harteck, Bonhoeer,
Wirtz and myself present from the physical
side; the chemists Albers, Schmitz-Dumont and a
third described their attempts to make volatile
uranium compounds [to replace the corrosive
uranium hexauoride in the various isotope-separation
processes]. Esau is getting ready to
throw in the towel in January or February.

It seems that they now think the solution of a
certain problem can have no bearing on the out-come
of the war after all."

The Germans basically gave up high level centrifuge enrichment
at this point and concentrated on low level enrichment for
a power reactor design and they made little progress even on that.
The total budget allocated to German enrichment programs in 1944
was 200,000 Reichmarks. The 3rd and final enrichment
machine to be built (and the only one to work) was run in July
1944 and managed to produce 2.5 grams of Uranium enriched to
3.7%. This was of course a small fraction of the daily output
of the Oak Ridge plant.

They were not only behind the American, British and Soviet
programs but even the Japanese had a better grasp of the basic
physics involved, thats hardly surprising either since most
German physicists had either been expelled or had fled the country.

I suggest you read The Virus House by David Irving.He's not a
historian I'd usually recommend but given that his tendencies are
largely pro German you may find his writing more compelling and you
can down load it free from

http://www.fpp.co.uk/books/VirusHouse/

Keith

In article ,
(The Enlightenment) wrote:

Chad Irby wrote in message
. com...

Nope. Velocity is velocity, and coming in out of vacuum means those
steel wings are just little flanges out in the Mach-20 airflow waiting
to be melted - or broken off altogether.

Nope. There is someting called a hypersonic L/D (lift to drag ratio).

Yes, there is. And it tells us why those wings would have melted off.
To get enough lift to bounce the Silverbird out of the atmosphere again,
you have to deal with the drag of having it in the atmosphere for a few
minutes. Certainly long enough and hot enough to melt those little
steel wings, as demonstrated by the short X-15 flights with even tougher
alloys at lower speeds.

You can fly in and limit you rate of decent in a winged or lifting
body thus limiting peak heat to the extent that ablatives or even
tiles can be dispensed with.

Up to a point, but you still have to deal with *extreme* temps, in the
thousands of degrees range instead of hundreds, and boiler-type
stainless is *not* going to do the job, especially in the thicknesses
you need to use in spacecraft. The only way to get a decent lifetime
out of the stuff at Mach 10 would be to make it prohibitively thick, and
replace it after every flight.

So the Silverbird could have managed about Mach 3 for a short period of
time, about 1/5 of the *necessary* speed for suborbital missions like
the one it was designed for... and then would have had to be scrapped
due to overheating of the structure.

It could have managed more than mach 3 easily.

For a *very* short period of time, like the Mig-25. Then it would run
out of fuel or melt. Sustained speeds at Mach 3 just aren't feasible
with low-temp alloys.

The vehicle could have achieved sub orbital velocity at 13,000 mph.

....and melted in extremely short order.

Re-entered and slowed to a slower speed say 8,000 mph and skipped to
cool of and so on.

As I've mentioned several times, not with the materials they had
available in 1945. Repeating this false assumption does not make it
suddenly become true.

At a "mere" Mach 6, the X-15 skin reached 650 to 700 degrees C, in a
minute and a half of powered flight. This would have happened to the
Sanger several times per mission, with a skin that didn't have the heat
resistance of the X-15's.

Sanger is also higher up in thinner atmosphere.

The X-15 hit Mach 6 and max temp at about the same altitude the Sanger
was supposed to be at when it "skipped."

It skips up and down and was actualy to cruise at more like mach 10.

And when it reentered the atmosphere, it would melt unless they
redesigned it with better materials.

...you also left out the two or three Silverbirds that would have been
lost due to the control problems inherent in supersonic flight. And
then the one or two they would have lost due to the skin peeling off.
And then one or two due to not knowing about how to support a man in
space...

The vehicle had an all moving tail.

An all moving tail is nice, but it's not a prerequisite of super- and
hypersonic flight, and it certainly would not have made the rest of the
design workable.

Either way Sanger was using the first hypersonic wind tunnel in the
world to test his model.

And I'm sure that foot-long model would have showed all of the issues
I've mentioned. Oh, wait, it wouldn't. All it did was show how the air
flowed around a solid machined model of the Silverbird.

No doubt other materials were in development. Eg double walled
skins, ablatives etc.

Replace "were" with "would have to be once they started actually
thinking about it."

They were thinking about it.

Not in any reference I've ever seen. Most of the books I've seen on the
Silverbird are quite adamant that Sanger didn't spend much time on the
bomber after the initial concept, and spent *no* time on heating issues,
other than "it's going to cool off between skips." It was a concept
with a tiny bit of research after the fact, but nothing like what you
imagine it to be. Sanger spent a lot more time on his design for a
ramjet-powered interceptor (which also never flew).

They apparently had a ceramics heat shield program (for Sanger at
least it appear) and more than one hypersonic wind tunnel working on
problems.

Nope. They had *one* hypersonic tunnel in use in 1944, and it had a
very short (~30 sec) operating period (vacuum-operated). The Sanger
model was only tested for general ariflow, and they had *no* facilities
at the time for extended hypersonic flow runs. There were plans to
build a sustained hypersonic tunnel towards the end of the war, but the
Germans never finished it.

Just about everying was anticipated, heat shielding included.

Sanger spent no time studying the problem before the end of the war.

The biggest problem is heat shielding. Sanger had a hypersonic wind
tunnel to test hypersonic L/D. Controll surface effects, stability
and propably even heat build up issues could be tested.

No, they couldn't. While small hypersonic tunnels are good for general
airflow testing, they're lousy for extrapolating up to full-size
machines.

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

As I've mentioned several times, not with the materials they had
available in 1945. Repeating this false assumption does not make it
suddenly become true.

At a "mere" Mach 6, the X-15 skin reached 650 to 700 degrees C, in a
minute and a half of powered flight. This would have happened to the
Sanger several times per mission, with a skin that didn't have the heat
resistance of the X-15's.

You obviously don't know much about the SS Technical Branch and their
work in metallurgy. Documents recovered at Gottingen and Volkenrode
indicate that between 1943-44 the SS were experimenting with a
frictionless metal called "Luftschwamm" (Aerosponge) that could
withstand 1000 degrees Centigrade.
The experimental compound alloy was classified by the US... and
probably found its way onto some of the early US replicated disc
designs at Wright Field.
As I pointed out many threads ago the SS Technical Branch (especially
the E-4 Unit) holds the key to much of the amazing technology
discovered at the close of the war. The SS were put in charge of
developing new manufacturing methods, exotic metallurgy, alternative
fuel sources, energy field weapons, development of chemical and
biological weapons, advanced jet and rocket aircraft, disc aircraft,
and the future of ballistic missile technology. Albert Speer, as
armaments minister, talks about this in his lesser-known book
"Infiltration". Anyone interested in advanced, little known weapons
and all aspects of the SS organisation should read it.

Rob

In article ,
(robert arndt) wrote:

As I've mentioned several times, not with the materials they had
available in 1945. Repeating this false assumption does not make it
suddenly become true.

At a "mere" Mach 6, the X-15 skin reached 650 to 700 degrees C, in a
minute and a half of powered flight. This would have happened to the
Sanger several times per mission, with a skin that didn't have the heat
resistance of the X-15's.

You obviously don't know much about the SS Technical Branch and their
work in metallurgy.

Well, you're wrong about that, too. They're mentioned a lot in Leslie
Simon's book "Secret Weapons of the Third Reich," for example. They did
some interesting work, but had a bad tendency to announce new projects
and concepts well before they were finished, and a lot of their stuff
(like the metal you mention) were unfinished research projects. They
werealso crippled by the same tendency shown by most of the Gernam
research establishments, in that they were terrible at communicating
their successes and failures to the rest of their research institutes.

Documents recovered at Gottingen and Volkenrode
indicate that between 1943-44 the SS were experimenting with a
frictionless metal called "Luftschwamm" (Aerosponge) that could
withstand 1000 degrees Centigrade.

"Experimenting with" and "got to work" are two separate things.

Especially since that mythical metal you just mentioned never saw the
light of day except in some of the more exotic conspiracy theories.

And, again, the folks in the Silverbird project never knew about it,
since their entire design was based on normal, off-the-shelf stainless
steel, since Sanger and his boys never worked out the heat problems of
the concept. That's all it really was, you know... just a neat concept
without any real research behind it.

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

From: (robert arndt)


snip
Albert Speer, as
armaments minister, talks about this in his lesser-known book
"Infiltration". Anyone interested in advanced, little known weapons
and all aspects of the SS organisation should read it.

Rob

Albert Speer was a butcher and a liar. His books are full of self agrandizement
and self flagellation to prove his "veracity."

The man was a Nazi swine and should be read with great skepticism.

It was due to his reorginization of armaments after Todt died that dragged the
war on longer than it would have lasted. It was his heavy use of slave labour
and concentration camps that caused a great deal of misery and death. He should
have hanged with the rest. I hope he's rotting in Hell.

Dan, U. S. Air Force, retired

(B2431) wrote in message ...
From: (robert arndt)


snip
Albert Speer, as
armaments minister, talks about this in his lesser-known book
"Infiltration". Anyone interested in advanced, little known weapons
and all aspects of the SS organisation should read it.

Rob

Albert Speer was a butcher and a liar. His books are full of self agrandizement
and self flagellation to prove his "veracity."

The man was a Nazi swine and should be read with great skepticism.

It was due to his reorginization of armaments after Todt died that dragged the
war on longer than it would have lasted. It was his heavy use of slave labour
and concentration camps that caused a great deal of misery and death. He should
have hanged with the rest. I hope he's rotting in Hell.

Dan, U. S. Air Force, retired

Done with your tirade against Speer? I wasn't talking about the man's
morality here or his great organizational skill (which was miraculous
considering nazi duplicity and hoarding of materials).
What I was pointing out is that his book "Infiltration" opens up the
entire SS organization which was a state-within-a-state. Hitler was
the Fuhrer but Himmler ran the Reich with brutality.
Most people are familiar with the Allgemeine SS, Einsatzkommandos, the
elite Waffen SS, the SD, Gestapo, etc... but how many know of the SS
religious order Black Sun, the Archeological Branch, or the Technical
Branch?
The Technical Branch information is rare and Speer goes through many
of the projects and resources the SS were using at the close of the
war. I also believe that it is the only place you will find a Nazi
official actually comment on German disc aircraft. Speer says although
there was persistant talk of "flying tops" and that the SS requested
massive slave labor for the Kahla Complex where they were to be built,
Speer was not told what the SS were working on except that radical new
secret weapons would be produced there.
Speer goes into detail about the SS prefabrication methods, advanced
metallurgy, alternative fuels and engines, free energy machines (aka
Hans Coler's), electrical field weapons, a death ray (microwave
transmitter), and so on. Furthermore, he states that the SS
sub-contracted heavily so that by wars end very complex pieces to
advanced weapon systems and technology were discovered all over
Germany by the Allies, who had no idea what those pieces went to. The
final assembly areas of much of this tech were evacuated in 1945 and
the slave laborers killed to leave no trace.
Even though you might hate Speer, the book is worth the read for the
material it contains. No German Secret Weapons book from any time
period has any length devoted to the SS Technical Branch and herein
lies the mystery of a number of exotics, including all the occult Vril
and Thule discs as well as Rudolf Schriever's Flugkreisel,
Schauberger's Repulsin motors,etc...

Rob

From: (robert arndt)

Even though you might hate Speer, the book is worth the read for the
material it contains.

Rob

You missed my point entirely. I will simplify it for you. Speer's books are as
much fiction as they are fact. I will give you an example fom his book Inside
the Third Reich. He says by the time he made up his mind to introduce poisonous
gas to Hitler's bunker the vents had been built taller than he could reach. How
convient. It makes him look like he actually planned to kill Hitler.

Instead of worshiping Speer's "accomplishments" and "knowledge of projects" how
about recognizing he was a liar and a mass murderer whou was interested in
rewarming his legacy. Assuming Speer was correct about some projects and wonder
materials being designed please not that 63 years later most of these magicks
still haven't made an appearance. As for "opening up" the SS system Speer was
only repeating (or making up) some impractical, impossible (then and now) and
generally loony projects usually attributed to "German scientists" and claiming
the SS was doing it.

I have had my fill of Nazi "wonder weapons" and secrets still kept. Speer was
the only one in the Nazi hierarchy that attempted to organize a coherent arms
program, but he still was a butcher and a criminal. I say again all his books
were written to make himself look good so no one would deface his grave after
he went to Hell.

The U.S. , U.K., U.S.S.R., Japan and everyone else was working on fantastical
and strange projects that defy belief also.
Just like the Nazis most of the wackier ideas never got beyond the proposal
stage.

The Nazis didn't even heve the metals to make reliable jet engines.

Dan, U. S. Air Force, retired

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

Chad Irby wrote in message
. com...

Nope. Velocity is velocity, and coming in out of vacuum means those
steel wings are just little flanges out in the Mach-20 airflow waiting
to be melted - or broken off altogether.

Nope. There is someting called a hypersonic L/D (lift to drag ratio).

Yes, there is. And it tells us why those wings would have melted off.
To get enough lift to bounce the Silverbird out of the atmosphere again,
you have to deal with the drag of having it in the atmosphere for a few
minutes. Certainly long enough and hot enough to melt those little
steel wings, as demonstrated by the short X-15 flights with even tougher
alloys at lower speeds.

The USAF and NASA engineers who did the Black Horse SSTO (Single Stage
to Orbit) designe study make the following claims:

http://www.risacher.org/bh/bh-faq.html

"Q: How will the Black Horse protect itself from melting when it
re-enters?

A:Reentry heating is a strong function of wing loading. The Space
Shuttle has a highly loaded wing, at over 120 lbs/ft2. The Black Horse
has a 20 lbs/ft2 wing loading. Some at Boeing believe it could be
possible to build an all metal aircraft (Applying Inconel, Rene 41,
etc.) since their in-house RASV design used all metal integrated
structure/tankage/TPS. (And handled cryogens, too!).
(Mitchell Burnside Clapp, ) "

More info here on Black Horse:
http://www.risacher.org/bh/analog.html

******************

The Germans didn't have alloys like inconel, rene 41 or the British
Nimonic series because these alloys have an 80% nickel content. (All
melt at about 1400C) but they had something close.

The Germans used alloys like Tinadur (Chrome,Nickel,Titanium 70% Iron)
and Cromadur (Chrome, Manganese, 70% Iron) for the turbine blades of
the Jumo 004B-4 Jet engine used on the Me 262. (Both types were were
used on the 004B-4 since insufficent production of either alone was
avaialble) The reason is that the Germans had a severe nickel
shortage. The problem was that without nickel creep strength falls of
after 600C more rapidly than the high nickel alloys even though
overall strength remains similar and the melting point is still around
1400C. (As a result the Germans had to x-ray and recycle their
turbine blades at 25 to 60 hours or about every 16 to 32 missions)

Cromadur is interesting in that is is weldable and maleable.
Cromadure blades were made by bending and welding along the trailing
edge.

Thus the Germans had alloys similar to inconel that melted at 1450C
and opperated at 750C as turbine blades. These were inferior in creep
strength but not melting point. I'd say their metalurgy were good
enough for Silverbird.

Sanger silver bird re-enters after a few skips at much less than the
17000mph of the all inconel Black Horse and Much less than even its
own 13000mph top speed becuase it has skipped to even less speed.

Remember that KE = 1/2mv^2 so by halving the rentry speed you 1/4 the
heat buildup.

Sangers work on re-entry was pioneering and very respectable. He did
Hypersonic wind tunnel testing. He had sueprsonic wing profiles and
he made use of ligtinn bodies. He build high impulse LOX/Kerosene
rocket engines that had the impulse needed to achieve the mission.
















You can fly in and limit you rate of decent in a winged or lifting
body thus limiting peak heat to the extent that ablatives or even
tiles can be dispensed with.

Up to a point, but you still have to deal with *extreme* temps, in the
thousands of degrees range instead of hundreds, and boiler-type
stainless is *not* going to do the job, especially in the thicknesses
you need to use in spacecraft. The only way to get a decent lifetime
out of the stuff at Mach 10 would be to make it prohibitively thick, and
replace it after every flight.

So the Silverbird could have managed about Mach 3 for a short period of
time, about 1/5 of the *necessary* speed for suborbital missions like
the one it was designed for... and then would have had to be scrapped
due to overheating of the structure.

It could have managed more than mach 3 easily.

For a *very* short period of time, like the Mig-25. Then it would run
out of fuel or melt. Sustained speeds at Mach 3 just aren't feasible
with low-temp alloys.

The vehicle could have achieved sub orbital velocity at 13,000 mph.

...and melted in extremely short order.

Re-entered and slowed to a slower speed say 8,000 mph and skipped to
cool of and so on.

As I've mentioned several times, not with the materials they had
available in 1945. Repeating this false assumption does not make it
suddenly become true.

At a "mere" Mach 6, the X-15 skin reached 650 to 700 degrees C, in a
minute and a half of powered flight. This would have happened to the
Sanger several times per mission, with a skin that didn't have the heat
resistance of the X-15's.

Sanger is also higher up in thinner atmosphere.

The X-15 hit Mach 6 and max temp at about the same altitude the Sanger
was supposed to be at when it "skipped."

It skips up and down and was actualy to cruise at more like mach 10.

And when it reentered the atmosphere, it would melt unless they
redesigned it with better materials.

...you also left out the two or three Silverbirds that would have been
lost due to the control problems inherent in supersonic flight. And
then the one or two they would have lost due to the skin peeling off.
And then one or two due to not knowing about how to support a man in
space...

The vehicle had an all moving tail.

An all moving tail is nice, but it's not a prerequisite of super- and
hypersonic flight, and it certainly would not have made the rest of the
design workable.

Either way Sanger was using the first hypersonic wind tunnel in the
world to test his model.

And I'm sure that foot-long model would have showed all of the issues
I've mentioned. Oh, wait, it wouldn't. All it did was show how the air
flowed around a solid machined model of the Silverbird.

No doubt other materials were in development. Eg double walled
skins, ablatives etc.

Replace "were" with "would have to be once they started actually
thinking about it."

They were thinking about it.

Not in any reference I've ever seen. Most of the books I've seen on the
Silverbird are quite adamant that Sanger didn't spend much time on the
bomber after the initial concept, and spent *no* time on heating issues,
other than "it's going to cool off between skips." It was a concept
with a tiny bit of research after the fact, but nothing like what you
imagine it to be. Sanger spent a lot more time on his design for a
ramjet-powered interceptor (which also never flew).

They apparently had a ceramics heat shield program (for Sanger at
least it appear) and more than one hypersonic wind tunnel working on
problems.

Nope. They had *one* hypersonic tunnel in use in 1944, and it had a
very short (~30 sec) operating period (vacuum-operated). The Sanger
model was only tested for general ariflow, and they had *no* facilities
at the time for extended hypersonic flow runs. There were plans to
build a sustained hypersonic tunnel towards the end of the war, but the
Germans never finished it.

Just about everying was anticipated, heat shielding included.

Sanger spent no time studying the problem before the end of the war.

The biggest problem is heat shielding. Sanger had a hypersonic wind
tunnel to test hypersonic L/D. Controll surface effects, stability
and propably even heat build up issues could be tested.

No, they couldn't. While small hypersonic tunnels are good for general
airflow testing, they're lousy for extrapolating up to full-size
machines.

In article ,
(The Enlightenment) wrote:

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

Chad Irby wrote in message
. com...

Nope. Velocity is velocity, and coming in out of vacuum means those
steel wings are just little flanges out in the Mach-20 airflow waiting
to be melted - or broken off altogether.

Nope. There is someting called a hypersonic L/D (lift to drag ratio).

Yes, there is. And it tells us why those wings would have melted off.
To get enough lift to bounce the Silverbird out of the atmosphere again,
you have to deal with the drag of having it in the atmosphere for a few
minutes. Certainly long enough and hot enough to melt those little
steel wings, as demonstrated by the short X-15 flights with even tougher
alloys at lower speeds.

Thus the Germans had alloys similar to inconel that melted at 1450C
and opperated at 750C as turbine blades. These were inferior in creep
strength but not melting point.

So in other words, even if they used those alloys, the plane would have
come apart or deformed, or he would have had to build them out of much
thicker pieces of metal.

I'd say their metalurgy were good enough for Silverbird.

Too bad they never got around to using it. Once again, the design for
the Silverbird had *nothing* in it about high-temp metals - just plain
old stainless steel, which you finally admit is not good enough, after
trying to claim that boiler-type stainless was good enough.

Sangers work on re-entry was pioneering and very respectable.

He did almost *zero* work on re-entry. With the machinery he had
available, all he could do was very short tests on shockwave formation.

He did Hypersonic wind tunnel testing.

....on tiny little models of the Silverbird, for less than 30 seconds at
a time, with *no* heat testing, and could not have done any different
with the equipment he had during the war.

--
cirby at cfl.rr.com

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Slam on brakes accordingly.