Re: Before it was Rare Bear
NO2 adds additional oxygen to the combustion chambers increasing cylinder pressure and subsequent power. But additional oxygen requires additional gasoline to maintain the correct mixture, so when you introduce NO2 to any piston engine, you also need to introduce more gas. As more fuel/air is packed into the combustion chambers (whether by nitrous oxide or supercharger boost), the limiting factor becomes detonation.
In the Bearcat, and in the German fighters that pioneered GM1 (as they called it), NO2 had the additional effect of cooling the air intake charge, in a similar way as ADI (water/methanol- again pioneered by the Germans). So I believe that as NO2 is introduced, ADI might need to be reduced, otherwise, some liquid would fall out of suspension and there would be water running down the intake runners. Not sure if that was ever an issue in Rare Bear but the WWII engine developers did run into that problem.
Putting the NO2 spray bars in the Bear wing root intakes is really interesting. None of the WWII systems did it that way that I'm aware of. But on the Bear with the speeds it is capable of, air compression is already happening at those wing root intakes due to ram air effect? So introducing Nitrous there could help cool and condense the intake charge before it reaches the carb maybe?
Meeting the assistant to Kurt Tank would have been a fascinating conversation. Focke Wulf was experimenting with Nitrous and water/methanol very early on, with the BMW radial and the Daimler and Jumo V12s. Very cool.
Thanks to all for the fascinating descriptions.
NO2 adds additional oxygen to the combustion chambers increasing cylinder pressure and subsequent power. But additional oxygen requires additional gasoline to maintain the correct mixture, so when you introduce NO2 to any piston engine, you also need to introduce more gas. As more fuel/air is packed into the combustion chambers (whether by nitrous oxide or supercharger boost), the limiting factor becomes detonation.
In the Bearcat, and in the German fighters that pioneered GM1 (as they called it), NO2 had the additional effect of cooling the air intake charge, in a similar way as ADI (water/methanol- again pioneered by the Germans). So I believe that as NO2 is introduced, ADI might need to be reduced, otherwise, some liquid would fall out of suspension and there would be water running down the intake runners. Not sure if that was ever an issue in Rare Bear but the WWII engine developers did run into that problem.
Putting the NO2 spray bars in the Bear wing root intakes is really interesting. None of the WWII systems did it that way that I'm aware of. But on the Bear with the speeds it is capable of, air compression is already happening at those wing root intakes due to ram air effect? So introducing Nitrous there could help cool and condense the intake charge before it reaches the carb maybe?
Meeting the assistant to Kurt Tank would have been a fascinating conversation. Focke Wulf was experimenting with Nitrous and water/methanol very early on, with the BMW radial and the Daimler and Jumo V12s. Very cool.
Thanks to all for the fascinating descriptions.
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