DA-50 (gas) engine:
Prelim info at the diamond site:
http://www.diamond-air.at/de/einmotorige-flugzeuge/coming-soon-da50-be-unique/
So 173 kts at 14’000 is Mooney Ovation territory, somewhat slower maybe – presumably achieved at MCP, which is going to be way more power than the Ovation at 14k. Granted the cabin is much wider. I wonder what the consumption at MCP is. Presumably the 375hp Lycoming is there in a bid to go after the Acclaim speed record.
The weights seem very impressive. With full tanks you can load up 5 people and luggage and haul them for 1000 NM at FL200. The speed is not very impressive.
Shorrick_Mk2 wrote:
I wonder what the consumption at MCP is
At Aero, Dries claimed that fuel consumption of this engine is linear to power, so (assuming MCP would be around 90%) the fuel flow would be 12,2 gal/hr.
Let’s make that 13 at least?
This is the fuel flow table for the Austro Engine in the DA62. In my experience it is quite accurate.
Peter wrote:
The sort of curve which any internal combustion engine will do is a bit like this and you can see the fuel flow and power do not converge at 0,0. However, over a narrow range, stochiometric, the HP will be fairly linear with the fuel flow.
“Linear” only means that the relationship is of the form y=ax+b. b does not need to be zero. The best economy curves in your diagram are linear (straight), while the best power curves show a bend which should be expected as more fuel is needed for cooling at higher power settings.
Btw, is there any indication (or best estimate) on the pricing? Choosing between DA50 and DA62 would be hard. Althou two engines gives you more reliability, the pricing plays one part too when choosing your traveller.
Hauling 5 (or even 4) adults and luggage with full tanks sounds super good. Speed is “enough”, althou this can also change when we know how fast the different models will be with options they have.
Peter wrote:
fuel flow and power do not converge at 0,0.
I bet pounds for pennies that 0 fuel = 0 bhp and viceversa.
On another note I love the slotted flaps. Wonder what that does to stall speed.
An engine driving a constant speed propeller tends to increase in efficiency with increasing power because friction losses remain constant at constant rpm. If you’d like to attain similar efficiency at low power you need to slow the engine down while maintaining cylinder pressure. Diesels have an advanatage in doing this because they don’t have have a fuel detontation issue in this regime. However this is of limited utility in an aircraft application for two reasons: (1) aircraft engines usually run at high percentage of rated power to do their job and (2) propellers have limited operational speed range.
There is one way to stop an engine burning fuel, and that is to shut it off. Otherwise, and including operation with output power = zero, i.e. at no load idle, the engine burns fuel. Internal losses are always there if the engine is turning.
