The 350hp Lyco is twin turbo-charged. My hangar neighbor got that beast in an experimental. He once came to me and told me that he figured out why his takeoff performance was so disappointing: the fuel flow at full throttle was less then 120l/h.
The engine looks very beefy, I wouldn't say it's almost the same as mine with a marginally thicker crank and higher RPM.
The airplane is a Comp Air 6, with 350hp it flies slightly faster than a C172.
The airplane is a Comp Air 6, with 350hp it flies slightly faster than a C172.
Sounds like a modern, efficient and cheap to operate aeroplane. Something aviation had to wait 110 years for...
The issue with the Porsche PFM engine was the predictable fault of car engine conversions - it was heavy, complex, and expensive to maintain. Mooney had to use the stretched fuselage to accommodate the weight of the engine, and that made it slow compared to the lighter Lycoming powered version. A smooth, refined dog in terms of performance.
I remember reading the reaction of the Porsche team leader when the engine was being withdrawn from the market. He said that while Porsche made their engines very pretty, Lycoming painted over the nuts and bolts like an industrial engine... But maybe, he said, this 'inferior' approach was really what the unsophisticated aircraft market needed. Yes, and maybe he learned something about selling engineering to people who value function over vanity - i.e. the aircraft market, not the market for toys.
Lycoming painted over the nuts and bolts like an industrial engine
That is just a crap practice, from Lyco and sloppy engine shops.
A decent engine shop will re-plate all the hardware, paint the crankcases separately, and bolt it all together with clean bolts.
Omni Metal Finishing does good Cad for aircraft engine overhaul shops, but whether you paint over it or not is a matter of choice. Some like the added protection, others like the look of bare Cad. It doesn't make much difference to function - its an engine not jewelry.
One problem is that paint isn't going to stick to cadmium plating unless you etch prime it... so painting over is just tacky, IMHO. All you get is corrosion happily starting underneath.
The other is that, on a newly assembled engine, it's normal to need to tighten up the crankcase bolts after a while, as the gasket compresses. If they are painted over, the result is even more tacky.
its an engine not jewelry.>
True, but there's a lot of money in jewellery!
"Where does the extra power come from? Obviously the MP won't change, and neither will the combustion chamber volume (significantly) so the mass of air getting sucked in at a given RPM will be the same, so for a stochiometric combustion the fuel flow must be the same, so any increase in >the power output must be due to the higher CR."
There is a theoretical (thermodynamical) efficiency of the Otto process and that efficiency is really rising with the compression ratio. Otto process is the one found in piston combustion engines.
The reason for this is that the graph of indicated pressures has a positive part (producing energy) and a negative part (consuming energy). The higher the CR, the smaller the combustion chamber, the higher the peak indicated pressure (adiabatic process), the bigger the positive part compared to the negative one.
Definition of the efficiency could be expressed like (positive-negative)/positive. With bigger positive in relation to negative the efficiency becomes a bigger number.
That means a theoretical piston engine's (thermodynamical) efficiency becomes higher with rising CR.
