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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. The only thing that prevented the production run of 70 extending to 1000 was allied bombing. http://www.centennialofflight.gov/es...ettner/HE6.htm 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 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. The wedge shapped wing profile shows a keen understanding of supersonic aerodynamics. The Germans had solved the hypersonic and heat shielding re-entry problems of the V2. They developed SR71 A12 like chine strakes becuase their theory and supersonic wind tunnels allowed them to: http://www.astronautix.com/lvs/a9a10.htm Perhaps Eugene Sanger was a dreamer but he was heading in the correct direction defining the problems that needed to be solved and then solving them. He got pretty damed close and a testing program would have refined the detail to a workable solution. He for instance ground tested his regeneratively cooled LOX/Kerosene engine at an Isp of 306 seconds. That's an entirely modern performance. http://www.luft46.com/misc/sanger.html A lot of the work supersonic and hypersonic that the Germans did in the Nazi era at Penemunde fed straight into the US. Walter Dornberger (Head of the V2 program) ended up working for Bell. http://www.astronautix.com/craft/dynasoar.htm http://www.luft46.com/misc/sanger.html After the war, he was asked to work (along with mathematician Irene Bredt) for the French Air Ministry, where in a bizarre plot, he was almost kidnapped by Stalin, who recognized the value of the Amerika Bomber. The US could do with a few more Nazi Era engineers. Apart from Bono and Hudson things have been **** with the US space program since they retired. |
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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? 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. 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). 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 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. You still need some very high-temp metals (Inconel or titanium, to start), instead of the normal stainless steel Sanger proposed. 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. 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. 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. Nothing like the 13,000 MPH the Sanger was supposed to hit. -- cirby at cfl.rr.com Remember: Objects in rearview mirror may be hallucinations. Slam on brakes accordingly. |
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![]() "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? |
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Breaking this into different posts, instead of one monster...
In article , "The Enlightenment" wrote: "Chad Irby" wrote in message m... In article , (The Enlightenment) wrote: 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. Exactly. Comparing a simple helicopter to a workable tilt-wing is just plain stupid. -- cirby at cfl.rr.com Remember: Objects in rearview mirror may be hallucinations. Slam on brakes accordingly. |
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In article ,
"The Enlightenment" wrote: "Chad Irby" wrote in message m... 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. ....and the technical problems inherent in that took over twenty years, just to get a decent handle on it, and a half-century to start getting to the point it's useful. Any idiot could draw a plane that had a tilt-rotor configuration. Making one work is a whole different thing. -- cirby at cfl.rr.com Remember: Objects in rearview mirror may be hallucinations. Slam on brakes accordingly. |
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In article ,
"The Enlightenment" wrote: 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? Try 150, *maybe*, once they got the massive problems involved with workable tiltrotor configurations out of the way. It's a huge amount of handwaving, though. "If magical faries came to Earth and gave them a workable transmission/power plant setup, and resolved the control problems, then they might have made the design work..." -- cirby at cfl.rr.com Remember: Objects in rearview mirror may be hallucinations. Slam on brakes accordingly. |
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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. 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. 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. 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... ...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. 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 dibule walled skins, ablatives etc. Replace "were" with would have to be once they started actually thinking about it." 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. 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. And a ten-year nuclear program to make a nuke small enough to carry in the darned thing... 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. -- cirby at cfl.rr.com Remember: Objects in rearview mirror may be hallucinations. Slam on brakes accordingly. |
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![]() "The Enlightenment" wrote in message ... "Chad Irby" wrote in message 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. Which does not make it the same as a tilt rotor. 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. You seem to be making light of that "transition from hovering to horizontal flight", it's a bear. |
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