Naturally the most important part of a biprop engine is the fuel system, as unlike other engine types the two fuels must actually be pumped into the combustion chamber where they mix and react. The fuels we chose for Epoch 1 were diesel and gaseous oxygen. Diesel is a great fuel because it is very dense, and it burns very hot with a relatively simple combustion reaction. Gaseous oxygen was chosen because it is fairly safe and very easily available, the biggest reason was our lack of experience with biprops. We felt that jumping right into Nitrous Oxide or Liquid Oxygen would end in a very large explosion.
Given the choices we made with fuels, the fuel system was left with very few options. The lack of a liquid state oxidizing agent immediately ruled out the standard impinging streams design. Therefore we decided on using a commercially available misting nozzle to disperse the diesel fuel into the chamber.
The oxygen was a little bit tougher. The oxygen injector needs to help disperse the fuel and be able to mix with it very quickly so all of the combustion stays within the given combustion chamber length. We decided on 16 holes drilled in 2 concentric circles and fed by a manifold. The manifold being fed by a custom oxygen "regulator" from our large welding tank.
In the center is the fuel misting nozzle, while the small holes around it are the oxygen injectors
Here we have the plumbing to feed the injector plate. The tube going into the center is the fuel line, this would lead to a compression fitting to connect to a long flexible fuel hose from our fuel tank, in which we store under pressure to remove the need for a fuel pump. The outer pipe feeds the oxygen manifold, this also connects to a flexible high pressure hose to our oxygen tank.