ok in that spirit here is a thought
We have 2issues working against us for high mileage. I will discount rolling friction) thermal inefficiency and aero drag.
The engine wastes heat 3 ways,
1 - thru the structure, and we can not do much about that.
2- thru the exhaust. a turbo will recover some energy but the compound engine is more directly aimed at range as it gears exhaust energy directly to the output shaft. These are not much use in this project as they add weight and complexity.
- the cooling system and we loose twice here because we waste heat energy and add drag pushing air thru the radiator.
Aircraft have long used pressure ducted cooling systems to reduce drag. One of the most efficient was way back in WW2 on the liquid cooled P51that ad a system of ducts and doors that had a worst case performance of 0 drag but some accounts claim a slight addition of thrust. Very possible as air enters the radiator and has heat energy added.
This leeds to why I was asking about your tail section design. If the aft section is pinched and flow seperation occurs a low pressure aera will likely form behind the vehicle. I have toyed with this idea for some time and plan to try it on one of the cars I am building. Carefully duct air from the area of highest pressure at the nose thru the radiator and exit the high energy expanding air out the back at the lowest pressure area. Hopefully there would enough energy added to eliminate the low pressure without resorting to a long tail section. Please excuse missing letters and numbers, I am afraid the cats have pounced on this keyboard 1 to many times.
We have several cats.
I don't let them in my office
Per your discussion points on engine thermal waste:
1. I agree with the fact that the gas engine is very inefficient. Heat is the main loss and I also agree that it would take some "start from scratch" engine design to address it. Those discussions are elsewhere and progress is being made. Unfortunately, my budget is limited so the CBR is my starting point. I do plan to wrap the exhaust which may help. I know it will help the engine compartment temperature.
2. My design takes into account the drag from the radiator. I have not seen the aircraft design that you describe, but it sounds like the idea I came up with. In fact, the air inlet to the radiator is my only intentional air opening. The air will be controlled into and out of the radiator. The idea is to not allow "dirty" air into the bike enclosure as managing it is difficult without disturbing the outside air flow or causing drag.
The only area I considered leaving open in the tail is a 3" center section for vacuum on the engine bay. That may still happen, but it will be limited. I also considered making this opening adjustable in the cockpit.
My design is a little like a plane. It has a canopy for a windshield and has landing gear (outriggers
Good points. Thanks for bringing them up.