I think .25 size fuel tank will be enough for me, I usually do not fly longer then 8-10 minutes. The fuel consumption concerned me just because it was not as low as expected, which means something is wrong...
I definitely overlooked the simple fact that diesels are intended for lower RPMs.
I have just checked the specifications from Enya website for Enya SS25DBB (Diesel) and Enya SS25BB (Glow):
SS25DBB TN (Diesel) For middle size scale or sport plane
Power 0.8 HP, Revo. range 2,500~9,000 rpm
SS25BB TN (Glow) For small size sport or trainer plane
Power 0.70 HP, Revo. range 2,500~16,000 rpm
One more question...
What should be the color of the exhaust residue at peak RPM? If it is almost black is it acceptable? I mean the exhaust is still wet and oily, but contains black fraction (soot ?).
Can it be because of too high compression?