Portable Flyer / PatATi Asymmetric Transfer & Intake 2stroke

[manolis]

Hello.

You may like to think (or dream) about this application:



It is an Opposed-Piston PatATi Portable Flyer having
80mm bore,
80+80=160mm stroke,
800cc,
540mm crankshaft axis to crankshaft axis distance (two directly-driven counter-rotating propellers, 1m diameter each),
perfectly "vibration free" and "reaction free" structure,
total weight less than 15Kp (33lb).

The second GIF is the one half of the Opposed Piston PatATi engine and shows the "internals".

The narrowing at the center of the cylinder of the OP PatATi engine enables a compact combustion chamber without spoiling the - loop - scavenging.
The spark plugs are located more centrally.
The narrowing causes the required squeeze during the combustion.
Without phase difference between the two crankshafts (yet, with asymmetric transfer and intake) and with the same instant pressure acting on the two piston crowns (common combustion chamber), the synchronizing mechanism (not shown) between the two crankshafts runs unloaded, so it can be lightweight and reliable, causing minimum power loss.

The two counter-rotating propellers act as the flywheels of the engine.

With the two oppositely moving pistons counterbalancing each other, the balance webs on the crankshafts have to balance only the mass of the crankpin and of the rotating part of the mass of the connecting rods (lightweight and compact cranks hafts).

At 5,000rpm the speed of the blade tip of the 1m diameter propellers is 260m/sec.
With 0.5Kg reciprocating mass per piston (it includes the mass of the piston, of the wrist pin and of the "reciprocating part - typically 1/3 - of the connecting rod) the resulting maximum inertia force is 700Kp at the TDC (at the BDC the inertia force drops to 400Kp; con-rod to stroke ratio: 2).
In comparison, with only 20 bar pressure inside the cylinder (20 bar is the BMEP - brake mean effective pressure - in the typical marine two-stroke supercharged engine), the resulting pressure force on each piston is 1,000Kp.



Application:

Imagine a pilot / rider wearing a wingsuit and having secured on his shoulders this Portable Flyer, flying only 2m above the sea (for safety) from island to island.

The pilot / rider can take off vertically, like a helicopter, and then he can progressively turn to horizontal fly, like an airplane, to cover the distance quickly and fuel efficiently (fast and cheap).

At landing he returns to "helicopter" mode to land vertically.

For more about the PatATi Aymmetric Transfer and Intake: http://www.pattakon.com/pattakonPatAT.htm


You can also take a look at http://www.pattakon.com/pattakonFly.htm wherein a perfectly balanced and reaction-free (the frame of the airplane is rid not only of inertia vibrations of any kind, but it is also rid of reaction torque even when the "throttle" opens wide suddenly or closes suddenly improving the stability) engine is presented:

[youtube]64TY-x2Cj6Y[/youtube]

Thoughts?

Thanks
Manolis Pattakos

[Frank Giger]

Awesome and horrifying at the same time.

I have an aversion to things spinning at high speed near my unprotected body - and there's nothing one could wear to protect against a prop strike to the body or head. Don't stumble on landing or muff the takeoff.

A ducted fan would mitigate the risks somewhat, but they have problems of their own.

I'm not saying it shouldn't be tried, just that I wouldn't want to be around anyone wearing a man pack slice-o-matic.

[manolis]

Hello Frank Giger.

With the "pilot / rider wearing a wingsuit and having secured on his shoulders this Portable Flyer", the pilot / rider cannot reach the rotating propellers.

The rest people have to keep a safety distance (just like in the case of a small airplane).

Thanks
Manolis Pattakos

[Frank Giger]

In a prop strike or departure of the prop from the mount the pilot is exposed to them; think about the requirement to keep people away from the pilot as he's landing for safety and then review the pilot's proximity to any mechanical mischief; he's actually the most at danger.

Anyhow, as I said I think it's a neat idea, just one I would never adopt.