Article Type: Military History
Article Date: September 23, 2002
Lufthahrt Forschungs Anstalt - Ainring
Dr. Ing. Eugen Sänger was a ramjet expert in the LFA’s research department at Ainring, Germany. The theory was simple: light off the fuel as air passed through a stove pipe and you have a powerful thrust. Ramjets were much simpler than jet turbines but the drawback was a needed 149 MPH speed so sufficient airflow could be produced before igniting the fuel. The V-1 used ramjet engines quite successfully after a catapult launch to speed.
As the war unfolded Germany realized that air vehicles had to have superior performance to contemporary ones if they were going to survive, much less combat the Allies’ vast aerial armadas. What about striking blows at them? By 1944 it was no longer possible with existing aircraft. New projects were soon encouraged.
Sänger’s aim was to develop a craft capable of reaching the United States, dropping presumably an A-bomb, and returning to Germany by circling the globe. But his concept was no Schnellbomber in the traditional sense. Before the sound barrier was broken the Air Ministry was looking for power to propel aircraft to Mach 3—2,284 MPH. Willy Messerschmitt, speed demon he was, had his eye on Mach 1 and was working to build a highly modified version of the Me 262 for that goal in early 1945.
But three times that speed was something else. Sänger knew that normal turbines and ramjets were not the answer at the stage of development they were in. He believed that specially fueled turboramjets and/or rocket engines could do the job by “bouncing off the denser atmosphere layers above the earth.” You begin to understand that statement when you realize he was talking about flying at an altitude of 90 miles!
 |
| Orbiter Skipping To USA |
The small wings (49.2’) and tail were only to give directional control during the atmospheric phase of landing of the 92-foot long craft. They wouldn’t do much at the proposed mission height at the edge of space. Successful wind tunnel tests were completed in 1944.
 |
| Orbiter With Booster On Launch Rail |
Ideally, a monorail launch ramp would get the 100-ton vehicle on its way. It would begin mildly then incline to near vertical where speed was sufficient to fly using the first stage rocket engine pack. As was calculated for the A-9/A-10 ICBM, the equivalent of six 56,000 lb. thrust A-4 (V-2) engines could lift that weight. At altitude the first stage boost rockets would break away.
The turboramjet principle is a turbine and compressor ahead of a ramjet. The incoming thin air at ultra high altitude would be compressed and fed to the ramjet where ignition occurred. Bypass ducts tapping air from the compressor would give the airflow needed to the afterburner for combustion and great thrust. Fuel candidates were methane and hydrogen. Propellant would contribute 89 tons of the 100-ton projected weight.
 |
| Cutaway Offers Some Details |
The orbital/intercontinental bomber was to hit Mach 3 and attain an altitude of about 105,000 feet or more but would cruise at about 963 MPH at that height. The probable range was 14,600 miles. But the turboramjet was only for atmospheric and upper stratospheric use. Once above the thick atmosphere layer much smaller rockets would boost the craft to ultimately 90 miles where it would skip off the thicker atmosphere on its course to the U.S. at 13,000 MPH!
Sänger believed space travel would soon be a possibility. With Werner von Braun’s V-2 further development he foresaw progression of his craft as the first space shuttle that would return for reuse going between earth and orbiting rockets that would then go into deep space. He believed atomic power was the way to ultimately go but no one has yet been able to create a reactor and motive power for any aircraft…that we know of.
His power concept was to be borne out with turbine/ramjet power in the experimental Me 262 using Jumo 004 turbines below with Lorin ramjets above the wings. Many Luftwaffe aircraft were already tested with big ramjets grafted onto them.
The Air Ministry believed Sänger’s theories were too far over the horizon of possibility of 1944. But the Russians didn’t think so. When the war ended he was a wanted man. A reward was offered for his whereabouts. He and his wife, who was a research scientist also, fled to France and worked on turbine engine aircraft design. The Russians had collected much of his paperwork and had the same notion of intercontinental vehicles.
This may all seem implausible for 1944 but it did later come to pass. Mach 3 friction was easily overcome by the “old fashioned” MiG 25’s use of tiny amounts of titanium on leading aerodynamic surfaces and normal materials throughout instead of nearly the whole plane as in the SR-71. It was typical German logic of WW II—due only the least necessary to accomplish the goal—don’t over build. Today’s aviation experts believe that the mystical Lockheed Aurora flies with a “scramjet” using similar fuels that Sänger considered.
Werner Von Braun Interceptor
So what else did Werner von Braun work on besides the V-2? Well, he had designs for a VTO (Vertical Take Off) rocket interceptor. He had two designs both fairly equal in size and performance differing in style only.
In 1937 he grafted a small liquid fuel rocket engine onto an He 112 that took off with conventional power but once the rocket was lit it shut down to be the first aircraft to fly on liquid rocket power alone.
 |
| Von Braun's 1st Design |
His later VTO interceptors were generally conventional with 28-foot non-swept wings and tail planes at the rear of the 30.5-foot fuselage weighing between 11-12,000 lbs.. The pilot had an armored, pressurized cockpit. The idea was that all the craft were stored vertically and rotated out via conveyer from their hanger and the rocket ignited. It would climb at just under 30,000 FPM to its ceiling of 26,247 feet using V-2 style graphite vanes to steer. With a 15-minute endurance it would continue after initial ground radar guidance to attack the bombers. Speed was estimated only about 435 MPH from the undisclosed thrust of a two-chambered rocket.
Weaponry was stated as four guns but the probable armament would have been 30 mm Mk 108s in the practice of the time. The Bachem Ba 246 was influenced by these designs but von Braun’s use of T-Stoff (80 percent hydrogen peroxide
with oxyquinoline or phosphate as a stabilizer and 20 percent water) and C-Stoff (57% methyl alcohol, 30% hydrazine hydrate and 13% water) was not practical fuel due to cost and volatility. The mechanized launch facility was too costly as well.
 |
| 2nd Interceptor |
His second craft used less explosive Vison and SV-Stoff (85-88% nitric acid and 12-15% sulphuric acid) and it could launch from the truck that could transport it. But for unknown reasons the Air Ministry didn’t pursue the project.
Dornier Werke GmbH - Friedrichshaften
This was not a wonder weapon as such, but its performance in 1940 was wonderful. In 1939 the Air Ministry- Reichsluftfahrtministerium (RLM) was already projecting a replacement for the He 111 and Ju 88. The goal was the “Bomber B,” a plane that had a 2,237-mile range bringing the whole British Isles within range from bases in Norway, Belgium, Netherlands and France. A speed of 373 MPH at 19-23,000 feet was required with a 4,400 lb. bomb load. This would place it in the speed range of the faster fighters of the day. It was said that it should use the advanced Daimler-Benz 24-cylinder, the DB 604, or the Junker Jumo 222.
Focke Wulf created the FW 191 and Junker the Ju 288, both of which the RLM considered more advanced technologically. The Do 317 was in limbo. In reality its performance was superior to the other pair with a 416 MPH top speed at 25,000 ft using a pair of 2,870 HP DB 610A/B 24-cylinder engines. It could haul a maximum bomb load of 12,346 though typical missions would carry 3,968 lbs. a range of 2,237 miles. With its full limit in fuel it could go 2,485 miles. Ceiling was 34,500 ft. at 52,910 lbs. maximum on the 85-foot (up from 67’ normal) span at 55 feet in length.
But by 1943 Dornier used the research to improve the Do 217 high-altitude recon bomber, the 217P-0. The Rechlin test center flew three examples in late 1943 with astounding performance. The DB 603B V-12s were supercharged by additional 605T engines. This arrangement was known as the HZ Anlage and produced 3,720 HP at takeoff with 2,880 still available at 45,000 feet! The 605T drove a two-stage turbo-supercharger installed in the fuselage center with large intercoolers beneath the wingspan of 80.25 feet. Air scoops for the blower filled the underside of the wing from engine nacelle to fuselage, which was 58.9 feet long.
The three-man crew in the detachable forward cabin had a pressurized environment thanks to a tap from the supercharger unit. Two Rb 75/30 cameras mounted in the belly. 1,102 lbs. of bombs could be carried on wing racks substituted for fuel tanks in the long-range recon role. A tail-braking chute was mounted for deceleration of the 31,600 lb. plane.
 |
| 488 MPH At 46,000 Feet!! |
The 217P-0 carried two forward firing 7.9 mm MG 81s with two more in lateral positions. Due the altitude and speed performance considered no tail armament was mounted. And what performance it was. The plane had a whopping 488 MPH top end at 46,000 feet with 53,000 the ceiling!!
After extensive testing no production orders materialized.
Daimler Benz
The penchant for semi-kamikaze weapons was never put to rest due to Hanna Rietsch who was a fanatic for the idea. Daimler Benz was drawn into the arena and concocted both the carrier aircraft and launch weapon craft but Focke Wulf was to build the mother craft, that could carry up to six tiny attackers, and the attackers.
 |
| Mother Ship |
Kamikaze missions were not approved for Luftwaffe pilots but the end result would have probably been such. Two diminutive jets were designed for the job. But the mother ship, called the Project Kamikaze Carrier “C”, was another bizarre form of craft using six DB 603Ns of 1,900 HP each along a 177-foot inverted gull wing spanning a 114.8-foot twin-boom fuselage supposedly good for 348 MPH. Two long, faired and fixed landing gears each had three in-line wheels allowing a horizontal squat like a tricycle gear would.
With five attackers attached beneath the wings the loaded weight would have been 268, 961 lbs. Range was expected to be 1,068 miles and climb 1,496 FPM.
 |
| Kamikaze |
The attack planes were of two types. The “E” had a 27.9-foot swept wing along a 30.2-foot fuselage with a swept tail. Power came from a single HeS 011 attached as a pod below the extreme rear fuselage. No landing wheels were needed. The construction was planned to be mainly wood with a 2.5-ton explosive nose. The cockpit was to be utilitarian and sparsely finished.
The “E” had a 3,968 lb. empty and 9,921 lb. loaded weight and a ceiling of 34,450 feet. It would have fuel enough for two hours flight and top speed was calculated at 576 MPH. Five could be carried on the “C” mother ship.
 |
| Kamikaze |
The “F” looked like the Fi 103 manned V-1 rig but with swept wings and tail. With a span of 29.5 feet and length of 42.5 feet. Six of these could hang onto the launcher craft. But power would have been the beefy BMW 018 jet with 7,500 lbs. of thrust and a maximum speed of 652 MPH. Further specifications are sketchy.
The idea that pilots could aim their high speed craft at a target and successfully bail out was ludicrous.
Focke Achgelis GmbH
With his pioneering work in helicopters, Dr. Heinrich Karl Johann Focke had already built and flown several designs. The Fa 223 was quite progressive with a twin rotor layout and seating for four in a fully enclosed fuselage. Three suvived the war in airworthy condition.
But Focke predated the Osprey tilt-rotor craft by half a century with his Fa 269! It was called a convertiplane back in 1943 during its design. The 32.9-foot wings each had a DB 605 at mid-span driving large diameter (16’ proposed) three-blade pusher props. The fuselage of 29.1 feet in length sat on a very snout-high landing gear with a transparent nose floor housing a 2-man crew. The possible uses in WWII are the same as today’s making it a handy aircraft.
 |
| Fa 223- Tilt-Rotor Pioneer |
In Focke’s layout he didn’t envision the whole wing rotating like the Osprey, only the engines and their props downward at 85-degrees. There was a special pivoting gearbox at the front of each engine, from which a drive shaft passed back between the engine cylinder banks to drive its propeller behind the wing’s trailing edge. In the completely down position, the propellers were almost parallel to the ground. For this reason a very long tail wheel was needed, which retracted into the fuselage. Maximum speed was reasoned to be about 373 MPH depending on the horsepower and engine model.
Further specs are not known. The project was dropped in 1944 since considerable development was needed for the special gearboxes, drives, pivoting mechanisms and prop pitch controls for landing and taking off. Perhaps though, THIS is the right way to do tilt-rotor!
Electrik Kanon
The prospective of launching projectiles with magnetic power has intrigued armament researchers since the electric solenoid came about. In World War II Germany commenced two individual projects to study electric propulsion. The first was led by an engineer named Muck who was a consultant to the Siemens company. His idea was that a solenoid triggered gun be built into the side of a hill near the Lille coal fields in France. 50,000 tons of anthracite (a hard coal giving high heat and little smoke) would need to be harvested each month to generate the electrical power for the gun. The gun, it was surmised, could hit London of 155 miles distant with a 450 lb. shell.
Reichsminister Albert Speer rejected it as impractical in 1943 after a group of scientists and technical experts scrutinized the proviso. Another idea from an engineer named Hansler in 1944 was based on the linear motor principle and calculated a 6,000-RPM (rounds per minute) ROF (rate of fire) from a multiple-barreled cannon with a velocity of over 6,000 FPS from 500 gram (about 1 1/8th lb.) explosive shells. (Sounds like a Vulcan to me!) The Luftwaffe was captivated with the basic perception for use as an anti-aircraft weapon.
Exhaustive tests with an electro-magnetic discharge mechanism were made on 20 mm anti-aircraft guns. Tests began in Berlin and were then continued in the foothills of the Alps. Test firings were carried out alongside the slopes of the Wetterstein mountain. Muzzle velocities of over 18,000 FPS were attained. Initial assessments showed that traditional generators could easily and inexpensively produce the necessary 3,900 kilowatts per gun. It was later deduced that a substantial amount of energy was needed so a new type of condenser was developed. It was believed that the new condenser would bring an enhancement, but the tests were not concluded before the war's end. Work on a prototype gun had begun in February 1945 but was not finished before the capitulation. The gun was captured by the Americans. After the war the Allies intimately studied the project. The eventual conclusion was that each gun would have required the production of a large city's power output. The project has never been restaged.
Sources
- Aeronautical Staff of Aero Publishers, Inc.
Kamikaze
Aero Publishers, Fallbrook, CA 1966
- Green, William
Fighters Vol. 1
Doubleday & Co. NY, 1960
- Green, William
Jet Aircraft of the World
Macdonald, London, 1955
- Green, Wm.
The Complete Book of Fighters
Smithmark Publishers, NY, 1994
- Green, William
Bombers & Reconnaissance Aircraft Vols. 7, 8, 9, 10
Doubleday & Co. NY 1967-67-67-68
- Heppenheimer, T.A.
Revealed! Mach 5 Spy Plane
Polular Science November 1988
- Munson, Kenneth
Helicopters Since 1907
The MacMillian Co. NY, 1969
- Myhra, David
Secret Aircraft Designs of the Third Reich
Schiffer Publishing, 1998
- Pocock, Rowland, F.
German Guided Missiles
Arco Publishing Co., Inc, N.Y. 1967
- Taylor, John W.R.
Helicopters & VTOL Aircraft
Doubleday & Co. Inc., NY, 1968