ORIGINAL: proanti1
It will be less powerful than a nitro engine, gasoline has a lower energy density. It will probably put out about the same power as the 5.9, which is why they are compensating with displacement. It will also have a slightly different powerband. Probably less torque and less top end, limited by the CDI.
Instead of just outright saying something wrong, why not research it a little bit first?
Nitromethane has a significantly lower energy density than gasoline: Gasoline provides about 42–44 MJ/kg whereas nitromethane provides only 11.3 MJ/kg.
The difference is, nitromethane's oxygen enables it to burn with much less atmospheric oxygen. 14.7 lb (6.7 kg) of air is required to burn 1 lb (0.45 kg) of gasoline, but only 1.7 lb (0.77 kg) of air for 1 lb of nitromethane. Since an engine's cylinder can only contain a limited amount of air on each stroke, 8.7 times more nitromethane than gasoline can be burned in one stroke. Nitromethane generates about 2.3 times the power of gasoline when combined with a given amount of oxygen.
So, it doesn't have a higher energy density. It just requires less oxygen to burn.
Size for size, a gas engine cannot match the power output of a nitro. However, the gas engine can make up for this deficit with larger displacement. A .26ci engine is 4.25cc. If HPI is talking 15cc, then there is your size to compensate for the increased oxygen necessary for similar power output. I don't think this is just a heli engine as some are saying. All it takes is a good combination of displacement, bore, stroke and airflow to change an engine's performance drastically.
I will have one of these engines in my Eight-T and XXL as soon as they are released.
HPI > *