One of the neatest things about nitromethane is the fact that it is a fairly slow burning fuel. It falls between gasoline and methanol on the scale when it comes to burn rate. One of the reasons you see those awesome header flames out of nitro burning drag cars is not only because the blower is typically shoving them out of the pipes but also because it takes a while for the stuff to actually finish being consumed. One of the reasons nitro engines run insane lead in the ignition is to get the party started so that when it is time to blast the piston down in the hole, the burn is in full swing.
This video below is cool because it shows nitromethane being ignited and burning in a container as shot in ultra slow motion. The film was made at Texas A&M in a lab where people study different propellants and stuff for the space program. We don’t know how long this took in real time but it was probably damned quick.
Remember, nitromethane has less energy stored in it per gallon than gasoline but it has the magic ingredient…oxygen. That oxygen allows the stuff to be firehosed into an engine and ignited. When you start to burning it in volume, the power potential grows exponentially.
So here it is, the slow burn!
Me thinks this video was speeded up not down. Nitro burns slow until it is compressed then the fun begins.
Cool video though
Anyone know how they got the nitro to burn? I have always heard (and seen) that nitro won’t ignite unless compressed.
One way to think of the ignition lead is that the volume of nitro compared to gas or alky is so much greater that it takes more time once lit to burn. Of the things I have noticed in drag cars is that nitro likes load and can burn more volume when it has more load. Load slows down the individual piston velocity thereby giving more time to burn so more fuel volume is needed. This also means it is twisting the crankshaft which accounts for the short life of the unit.