Smaller lighter faster engines are generally MORE efficient as their are less losses. You conjecture has validity if the Revetec ends up with the linear mass movement of the "normal" engines, but it replaces some of that and most importantly increases the energy extracted from the piston movement by operating with no side force vectors from cranks. IF they can run the engine at optimum revs for efficiency BECAUSE it produces higher torque then it wins. That is their stated position and THEY DO claim BETTER fuel efficiency. I've not seen anything that backs up to the contrary. As I said I think you speculation uses "normal" limits and tries to apply them to REvetec. I dont agree they're comparable.
yep, and HOW is that different to a gudgeon pin in a "normal" engine ?
I'd also forgotten that they have alignment shafts that retain piston alignment so would suggest removal of "slap" allowing a much smaller skirt and possibly lower mass piston.
How do you reach that conclusion ?
They are NOT subject to the needs of thinness of a conrod to be able move the piston. So they dont' need to be as substantially built. They are much shorter in throw too. The engine wins because it does NOT use a crankshaft -- which has counter weighted lobes -- and is more efficient in power extraction per combustion because there is no angular vector from a conrod.
??? Who told you that ?
The effect of gravity is MINISCULE relative to the combustion forces in the engine
PACKAGING. You get a WIDE engine hard to fit in.
Boxers are WIDELY used in light planes because then the packaging can actually be an advantage !! You dont' get many places where reliability and performance are any more important than a light aircraft
Boxers are a BIG win when you go air=cooled. But by the time you add a water jacket then a 4 isn't as efficient packaging as a straight.
Boxer and V180 are different as boxer is opposed piston and naturally balanced in all configurations whereas a V180 isn't. But the packaging is similar. There is a small difference in weight in the block but it' s arguable that the bottem end is stronger in a boxer wieight-for-weight as you dont' need to build extra ribs to stop the crank twisting out the bottom of a "normal" block.
NO, they coudln't control the VIBRATIONS that the unusual angle introduced.
Some of what you say is valid but there is a counter argument for each of them that the Revetec design seems to have used. I have commented where I think you take the poor points that a crank based engine has and then assumed it applies to the Revetec esp with regard to the cylinders. With NO sideways forces during the cycle then theoretically the block requires less stiffening, less thickness less weight !!
THE big benefit the Revetec design goes for is the removal of the angular forces a crankshaft imparts. SO removing all the necessary design to cope with those stresses and wear.