Originally posted by MajWoody
From wikipedia
Rocket fuel
While your post was interesting it has little to do with the Me163. The Me163’s motor was a binary fuel rocket not mono fuel.
Rocket Fuels
Liquid Fuels used in the 109-509 Series Motors.
T-Stoff - The Oxidant 1
The basis for almost all Walter rocket motors is hydrogen peroxide. With the chemical formula of (H2O2) it is an oxygen rich liquid which, upon decomposition, gives out heat at a rate equivalent to gunpowder.
T-Stoff is volatile and will naturally decompose, but the Walter Werke carried out a large amount of work to establish the correct dilutions and proportions to make the substance powerful enough for a motor, stable enough to store and capable of being controlled during decomposition.
T-Stoff was generally an 80% concentrated form, diluted with water, 20% by weight. When brought into contact with a catalyst, the peroxide decomposes into a mixture of superheated steam and oxygen, at around 500o centigrade. Fed directly to an expansion venturi, thrust will result. This basic process was used as the principle of Walter's so-called "Cold" Motors.
C-Stoff - The Fuel 1
To increase the efficiency of the motor, a fuel was injected into the mixture, utilising the oxygen released during decomposition to promote combustion.
The liquid fuel used was methyl alcohol, mixed with an organic compound called hydrazine hydrate. This latter was used to ensure the smooth, continuous combustion of the fuel.
The theoretical heat of this reaction would raise the temperature at the combustion chamber to over 1850o, so the actual C-Stoff fuel used, was a dilution with water. This kept the combustion chamber to a manageable 1750o. The difference in temperatures between this and the plain decomposition engine led to the fuelled motor being referred to as the "Hot" motor.
T-Stoff - In Detail 2
Hydrogen Peroxide H2O2 80% by Weight
Water H2O 20% by Weight
Stabilisers Phosphoric Acid
Sodium Phosphate
8-Oxyquinoline
The 20% dilution factor was tested by experiment. Walter research indicated that at concentrations greater than 85%, the peroxide would detonate rather than decompose in a controlled fashion.
The additives to the T-Stoff were to stabilise it, preventing it from decomposing during storage.
Walter Werke had also done a lot of research into suitable materials for engine components, as a number of metals caused the decomposition of the T-Stoff. To be avoided were copper and lead and any organic materials. At least one explosion at the Japanese factory attempting to develop their own copy of the Walter engine was due to using an organic-based gasket within a pump.
All organic and combustible materials had to be avoided because contact with the 85% peroxide would cause spontaneous combustion. Therefore, during any operations involving the movement or dispensing of T-Stoff, hoses of running water were always on hand to wash away and dilute any accidental spillage.
Materials that could be used, were austenitic steels,aluminium and polyvinylchloride (PVC) products.
C-Stoff - In Detail 2
Methyl Alcohol CH3OH 57% by Weight
Hydrazine Hydrate N2H4.H2O 30% by Weight
Water H2O 13% by Weight
Catalyst 431
Potassium Cuprous Cyanide K3Cu(CN)4
The fuel mixture was again discovered through careful experiment. The methyl alcohol (which was referred to as M-Stoff), was mixed with hydrazine hydrate (B-Stoff) which promoted an auto-ignition reaction in the combustion chamber and smooth combustion during operation.
An ideal ratio would have been to use 50% B-Stoff, but the experiments showed that a 30% ratio mixture is just as effective and a cheaper option.
To make the useable fuel, the chemical components were diluted with water.
To decompose the T-Stoff on demand required the presence of a chemical catalyst which promoted the reaction. A number of chemical salts carried this property, including manganese salts. However, in the final Walter motors, potassium cuprous cyanide was used, called Catalyst 431. This copper salt was preferred as it did not produce any deposits in the motor during combustion.
The catalyst itself was mixed in bulk with the C-Stoff fuel in the storage tanks. The fuel was then blown through with air to mix the catalyst and distribute it evenly in the liquid.
During operation, the correct proportions of C-Stoff and T-Stoff were sprayed into the combustion chamber. The presence of the catalyst decomposed the peroxide and the resultant heat of reaction with the presence of the hydrazine hydrate caused the auto-ignition of the methyl alcohol fuel.
The correct ratio of chemical fuels was C-Stoff:T-Stoff, 0.36:1. However, in order to more closely guarantee combustion, a slight excess of T-Stoff at the combustion chamber was preferred, so the actual ratios were closer to 0.29-0.32:1.
The Reactions 2
The peroxide, sprayed into intimate contact with the fuel in the combustion chamber undergoes the following chemical reactions.
With the Hydrazine Hydrate, the Peroxide is decomposed into nitrogen and very high temperature steam.
The methanol reacts with the peroxide to produce carbon dioxide and again water, although as we know, the temperature of reaction raises the state of this product to super-heated steam.
As a result, with complete combustion, the exhaust gases are comparatively safe and inert, although the temperature of the jet efflux will be in excess of 1800o centigrade.
In the earlier Walter motors for the Messerschmitt Me 163A Series, the "cold" reaction was initiated by a permanganate catalyst which stained the motor efflux purple.
Here, the catalyst was more neutral, and the motor exhaust was much paler, with a yellow/green almost transparent colour until the steam condensed into a dense vapour trail in the air. The power of the reaction, the velocity of exhaust gases and the narrowness of the venturi opening of the motor often led to "diamond" shock waves appearing in the high speed exhaust as Messerschmitt Komet aircraft began their "sharp starts" at take-off. The noise is described in a number of accounts in very colourful language, but must have been ear-splitting.
