“Manolis doesnt need to test, because he is always right.”
I know from tests and about their usefulness.
These two cars:
were tested on the roads for long, in various modes (from climbing slowly (with long gear in the gearbox) on steep uphill roads, to following city traffic, to “racing” on the highway (at 7,000rpm the first, at 9,000rpm the second, way above their factory red lines):
Surprisingly, these handmade VVA (Variable Valve Actuation) mechanisms proved (despite their bad manufacturing quality and their improper materials) the most reliable thing on the cars.
So, when the time comes, many-many tests will be performed.
But (hello Rodak
) to make tests in order to prove that the laws of physics are correct . . .
You also write:
“When the engine goes quiet you would not want to be more than a foot off the ground”
This is exactly the idea for long term reliability tests and for training:
To fly no more than a foot from the ground, or, better, no more than a few feet (say 1 to 10) above the water.
Imagine someone climbing on a tall / rough mountain, flying just 1ft above the rocks.
Or jumping from rock to rock with the Portable Flyer on his back taking the, say, 95% of his weight.
You also write:
“You do have some good ideas, but never the less still a compromise. Thermal loading for example.”
Cooling Outside the engine:
The cooling fins of the OPRE Tilting engines of the Portable Flyer are around the combustion chamber at the middle of the engine.
The cooling fins are eccentric relative to the propeller rotation axes, i.e. the cooling fins are where the downstream of the propellers is near maximum.
The cooling fins can substantially increase in size without affecting the design.
Cooling inside the engine:
The fresh charge entering into the “crankcase” (which is nothing but the inner side of the piston) is cooling the (rid of wrist pin) backside of the piston crown (the wrist pin is at the other end of the piston).
The pistons take the thrust loads at the cool side of the cylinder, away from the hot exhaust ports (where, typically, the scuffing starts).
The water cooling, which is always an option, is easier but it adds complications and weight (the worst things for a wearable Personal Flying Device).
The ULpower aero engines (more at https://en.wikipedia.org/wiki/ULPower_Aero_Engines
) are very proud for their air cooling (what is not there, cannot fail):