Rocket Engine Test Stands – Where Rocket Science is Proven

Oliver · 21st May 2020 at 1:37 am

Gasoline has more Energy per Volume and Weight and the ISP is higher. But its kind of dirty because it contains an unknown mix of Hydrocarbon of all sort.
This makes combustion unpredictable.
Ethanol is pure, clean, available and mix with water in all concentrations in this case 75% Ethanol.
The 25% water lower combustion temperature and hence stress on the material and cooling requirements with only slightly reduced ISP because of its low molecular weight.
Most important in regenerative cooled engines some of the Hydrocarbons in Gasoline will decompose through heat into gas and some kind of wax which will clog the fuel lines and destroy the engine.