In our reviews of weird and wonderful engines so far, we’ve marvelled at the “out of the box thinking” that’s involved. This time, we’re also shocked by the lethality.
In times of conflict, exploring ideas for advanced weapons isn’t unusual. Creating a device to kill and maim your own people is.
Article by Doug Switzer Moto/ology Publisher
The closing days of WWII saw Nazi Germany rapidly slipping into defeat. With the endless allied bomber streams flying over the Reich, the German high command knew something had to be done quickly to stem this tide. The British came by night and the Americans by day and together a ’round the clock tsunami of destruction rained down upon the people, towns and industries of the axis powers in Europe.
In a desperate and concerted effort to push back, the German High Command considered almost any suggestion for aircraft that could rapidly intercept and decimate the huge bomber streams. This situation was the catalyst for the creation of Hitler’s “Wonder Weapons”, new and awesome devices that would turn the tide and not only be effective at inflicting massive losses on the allies but would also strike awe and terror into those who encountered them.
With a minimum amount of warning, the Reich needed interceptors that could be armed and quickly flown to the high altitudes where the bomber streams operated. In the hectic mid-war years, no such production aircraft existed.
There had been considerable clandestine work undertaken on development of the turbojet engine and high-performance aircraft powered by these engines was seen as a viable component for inclusion in the plan. However, there was a faction that was preaching another more dramatic approach. Dr. Werner Von Braun along with other German scientists and technologists involved in rocketry were convinced their extremely powerful craft would fill the bill in a much more impressive and decisive fashion.
Enter, Hellmuth Walter and his compact, powerful and stupidly dangerous HWK rocket engine designs.
Hellmuth Walter had a background as a marine turbine engineer and had started working on a marine turbine design that used the chemical decomposition of hydrogen peroxide to produce the steam to drive the engine. He reasoned that this would be much more efficient in that it wouldn’t require outside air to operate and could produce much greater power from a more compact design. He had patented such a device by 1925, but his ideas were met with skepticism from most of his peers. However, seeing the possibilities of creating a sizeable market for his product, a Dr. Albert Pietsch, the owner of a chemical firm that manufactured hydrogen peroxide on an industrial scale, teamed up with Walter and with Pietsch’s financial support, the Walter Kommanditgesellschaft was established as a research and manufacturing company. This company was to be dedicated to the design, development and manufacturing of a range of novel hydrogen peroxide-fueled powerplants for the German navy to use in a new class of submarine. Early examples of these craft proved promising with submerged speeds more than three times that of the Kriegsmarine’s existing diesel-electric boats. Among his other patents and inventions was a version of the “snorkel” that was fitted to existing diesel-electric subs so they could operate in relative safety just under the surface while charging their batteries. With these successes, Walter now had genuine interest from some powerful and influential people, and this led to other ideas being developed, including some thoughts on alternative aircraft propulsion and this led to something quite outrageous for the Luftwaffe.
Walter’s experience with hydrogen peroxide-powered turbines had also initiated his experimentation with hydrogen peroxide-powered aerial engines that relied on the same rapid decomposition of this oxygen-rich fuel. His designs for a “cold” rocket engine competed with the highly volatile “hot” rocket liquid oxygen designs being simultaneously developed by Dr. Werner Von Braun. The Von Braun units had suffered from several catastrophic explosions and were proving troublesome to perfect, but Walter’s designs were showing promise and were installed in several test aircraft where they proved successful.
In fact, the first successful flight of a human in a rocket-powered aircraft was made by Fritz Stamer in 1928. He piloted a glider equipped with two black powder solid fuel rockets over a distance of 4900 feet/4193.5 metres. The glider, known as the Ente or “Duck” was a canard design–that is, it had the tailplane/elevator moved to the frontal position. The aircraft was designed by Alexander Lippisch who went on to design the Me163 rocket interceptor. The first human to fly in a liquid-fueled rocket was Erich Warsitz in 1939 in a purpose-built Heinkel He 176 experimental demonstration aircraft utilizing a Walter rocket engine. The plane had some very advanced features and showed convincingly the viability and practicality of rocket powered flight
Unfortunately, the powers that be were unimpressed with Heinkel’s accomplishment–many say because he had run afoul of some higher-ups in the Reich ministry, but at any rate, further work on rocket aircraft at Heinkel was abandoned and they concentrated on some experimental jet designs and more conventional aircraft.
Meanwhile, back at the Walterwerkes, they were now flush with funds from the German military establishment, this allowed continued development and testing on the various marine and aero powerplants. Significant progress had been made with Walter working on designs for torpedoes, missiles, aero-engines and rocket-assisted take-off boosters along with the aforementioned submarines.
Now, at this point we should point out that while the decomposition of an oxygen-rich chemical like hydrogen peroxide produces a useful means of power, we must also consider the properties of the “fuel” itself.
Nasty stuff that can go boom...
To anyone vaguely familiar with chemistry, it is fairly well-known that concentrated, pure hydrogen peroxide is dangerous stuff. It is only safe to be handled and used in very diluted forms. The pure liquid is highly corrosive to steel and iron and can cause serious chemical reactions to organic material and will spontaneously explode if it meets some materials.
A stabilised version of hydrogen peroxide, (chemical formula H202) was developed by the rocket scientists and called T-Stoff or “substance T”. This so-called stabilised mixture was 80 to 85% hydrogen peroxide mixed with 15 to 20% water along with some other trace additives. Due to its very dangerous oxidizing properties, it had to be handled with extreme caution. It is said that Dr. Alexander Lippisch, the designer of the Me 163 once said if you stick your finger into a container of T-Stoff, all you’ll be pulling out is the bone.
Add to this the explosive nature of the material and you can see that great caution must be excercised when working with it.
In the early Walter “cold” rocket motors, only a single hydrogen peroxide propellant was used to generate thrust through its controlled natural decomposition into oxygen and steam. However, it was found that greatly increased thrust could be generated with the addition of a hypergolic “fuel” into the equation. Later Walter rocket engines used the hydrogen peroxide-based T-Stoff as an oxidizer and introduced a second fuel component in the form of C-Stoff, a mixture of 57% methanol, 30% hydrazine hydrate and 13% water with a trace of a catalyst. The combination of these two mixtures created a hypergolic or explosive reaction merely by coming into contact with each other. The additional toxicity of these fuels meant that very strict measures had to be observed when handling them.
“Wie ein Floh, aber oho!”
On to the Me 163 Komet...
By the late 1930s, Alexander Lippisch had designed quite a few successful aircraft from gliders to trainers and beyond. His out-of-the-box thinking had led to the inspired designs of several “tailless” aircraft and their simplicity of form and refined function was appreciated by the pilots that flew his machines. Or at least this should have been the case. In fact, while some “tailless” designs behave remarkably well, there are sometimes other factors that come into play that overshadow things. This was definitely the case with the Me 163 “Komet”. This Lippisch design took the tailless concepts to new heights (pardon the pun!)
While most pilots who flew the Me 163 praised its flight characteristics very highly, the Komet had some deadly issues. The one great disturbing fact that hung over the airplane like a fearsome black cloud was its corrosive, volatile and downright dangerous fuel. First, the stuff was deadly and second, the little plane only carried enough for less than 8 minutes of powered flight. During this extremely limited time, pilots were expected to climb to the dizzying altitudes where the bomber streams operated, find them, make maybe a couple of attacking passes then glide back to base for re-arming and re-fueling. When coupled with a seemingly rushed design that left off a proper landing gear system and you have a great idea, spoilt.
One of the major shortcomings of the Me 163 design was that they did without a proper retractable landing gear system. For the sake of lightness, they instead opted for a simple retractable landing “ski” or skid like those that had been used on gliders. For take-off, a two-wheeled jettisonable dolly attached to the skid and was released once the plane became airborne. The failure of the skid to extend led to many spinal injuries for pilots and landing accidents when the planes were put into service.
Also, as mentioned earlier, the crazy fuels, T-Stoff and C-Stoff were unbelievably nasty and had to be put in very special containers. T-Stoff would corrode through iron and steel and spontaneously combust violently if it encountered cloth, leather or any organic material, including humans. It couldn’t be stored in anything but aluminum tanks and required incredible care when handling and during refueling. C-Stoff, on the other hand would dissolve aluminum and had to be kept in tanks lined with glass or enamel. T-Stoff was a mixture containing 80 to 85% pure hydrogen peroxide mixed with water and some traces of stabilizer chemicals like phosphoric acid. C-Stoff was used as a reductant in the Walter rocket motor to provide more “oomph” to the decomposition of the hydrogen peroxide-based T-Stoff. C-Stoff was composed of mostly methanol, (almost 60%) mixed with 30% hydrazine hydrate, the remainder being water and some potassium-based catalyst chemicals. C-Stoff and T-Stoff are hypergolic substances which means when they come together, they react violently and spontaneously explode.
This situation dictates that the ultimate care and cleanliness must be observed with these demonic substances. Add to these inherent dangers the fact that both concoctions were clear and looked the same and you can see big troubles ahead. When refueling the Me 163s the two trucks carrying the fuel components were forbidden to come any closer that 800 metres to each other. All containers and equipment used with T-Stoff were white while everything associated with C-Stoff was coloured yellow. Even with these precautions, quite a few catastrophic accidents occurred.
On one occasion, an inattentive worker in a poorly-lit shed mistakenly poured some C-Stoff into a container that had previously held T-Stoff. The resulting explosion blew the containers, the shed and the poor ground crewman to smithereens.
In another instance, while landing with tanks that were not quite empty, a Komet bounced along on its landing skid only to vanish in a spectacular explosion when apparently one of the tanks or lines burst and the contents came in contact with something undesirable.
Perhaps the most disturbing accident happened to a pilot, Josef Pöhs who had the misfortune to jettison his wheel-dolly a trifle too soon and it bounced back up off the ground, striking the Me 163 that had not gained sufficient height. The impact ruptured a fuel line and the toxic, acidic, nasty fluid began leaking into the cockpit area while the engine immediately shut down. Pöhs, in somewhat of a panic elected to attempt an emergency landing with tanks full of fuel. Upon touchdown, the heavy plane bounced then dug into the earth and turned nose-over. Observers were relieved there was no fire and no explosion, but according to fellow Komet pilot, Mano Ziegler, by the time the rescue crews could get to him, poor Pöhs was found still in the cockpit and partially dissolved in a pool of T-Stoff.
A great operational shortcoming of the Me 163 was its inability to actually bring down enemy aircraft. The plane was fast, very fast… and no allied fighters could catch it in the air. This also led to a big problem. Armed with two relatively slow firing 30mm cannons, the Me 163 closed on its prey so quickly, the pilots barely had time to aim and fire before they overshot their targets. It’s been said it required approximately five well-placed rounds to bring down an allied bomber so only the very best marksmen had any chance of scoring victories. In the end, when the final tallies were made, it appears that possibly between 8 and 18 allied aircraft were brought down by the Komet. Of these, surely some survived as escapees or captives. The number of Komets lost to combat in the one year period was 10 and accidents and mishaps accounted for “many more losses”. This brings about the ironic possibility that the Me 163 and its crazy rocket engine killed, maimed and injured more German pilots and crews than allied ones. One could wonder just who’s side Lippisch and Walter were actually on?
So, there we have it. The plane itself was pretty good. The engine and fuels it used? Not so much. The move towards aircraft that were much safer and performed just as well or better than the rocket fighter was realized when the jet engine technology grew and developed in the following years.
The Me 163 Komet has become a curiousity and a footnote. The hydrogen peroxide powered engine, however, has continued to be a dangerous device. It has been blamed for the loss of the Soviet submarine Kursk with all hands onboard. It is believed the sub was lost when a malfunctioning hydrogen peroxide-powered torpedo had a “runaway event”, ultimately exploding in the ship’s forward torpedo room and blowing the entire bow off the vessel. Crazy stuff.
For those who are interested, there is a lot of further information on the internet regarding these engines.
Watch for more Manic Motor articles in upcoming issues of Moto/ology!