Subject: [FlyRotary] Re: Oil Coolers

 

1450 Btu/min seems high to me. That is 35HP.  Where do these numbers come from, do others agree with this number?

 

Alex Madsen

 

My numbers come from heat balance plot for the rotary engine given as a function of the air/fuel ratio.  I chose to use near max power (lambda of 1.15) for the design point.  At that point the heat to the oil is about 7% of the total fuel burn energy.  That percentage increases just slightly as the mixture is leaned to somewhere in the 8-9% range for lean cruise condition.

 

The other interesting number is the heat to the coolant, which is about 18% at max power, and decreasing as the mixture is leaned, to about 11-12 % at lean cruise.

 

The total heat energy from the fuel burn is about 150 Btu/min per output hp at lambda of 1.15.

 

Al