I take back the wing loading comment. The title picture is deceiving, it has a much larger span when viewed head on and they claim a glide ratio of 22 to 1. Which is good.

The Learfan whose first test flight took place on "December 32nd" according to the UK government...

(Apparently the contract for the subsidy required the plane to fly by the end of 1980. Technical problems delayed the flight planned for the 31st so when it flew the next day the government decided it flew on the 32nd of December 1980 and therefore would get its subsidy. Sadly it didn't help in the end.)

The QLD Government placed an order for the Lear Fan.

True. It also effects prop efficiency and creates vibration.

Burt Rutan abandoned pushers for these reasons.

Still, a pusher behind a laminar flow body might be less affected by turbulence? By definition? That is assuming the wing and control surfaces don’t distort flow too much.

Well, that actually brings up ANOTHER point.

Their diagram showing a perfectly laminar flow over the fuselage is fanciful. Unless they've invented a new type of air, there is going to be a separation point and turbulent flow somewhere, and with a pusher that somewhere is definitely before it reaches the prop.

The pusher that fascinates me is the Dornier Do335 Pfeil (Arrow). I was very lucky enough to have a crawl over one in the Duetsches Museum in Munich in the late eighties. They were removing it from display to return it to the US. (It is now at the National Air and Space Museum). A true monster with that evil look only German engineers seem capable of designing. You could walk underneath the fuselage, it was that tall. With a speed of 400 knots, I guess it is proof of the advantages of keeping the wing clean. Again, you could hear it comming before you could see it, witnesses saying it gave a deep howl. So, a little hard to sneak up on people you wish to do harm.

Interesting observations by the English test pilot Eric Brown. In his book 'Wings on my sleave". He said, 'it was very fast, but could not turn for nuts'. This is the trouble with aerodynamics, everything is a compromise, or one win defeats another. Still, I would love to buzz the tower in a Do335 (upside down going flat out).

Claims 465mph on 500hp? It took nearly 2,000hp to get a sleek S/E fighter to 400mph and I don't suppose the physics have changed, even with laminar flow and it has probably twice the cross section.

On a 500hp diesel cruise is probably only 400hp at best and even with the torque a diesel puts out it still has to do the work for the whole trip.

Pusher props are inherently less efficient than tractor (I know, I had one!) As the drawbacks stack up you have to wonder how the figures will work out in practice.

(On the other hand I would really have liked to see the Aluminium VW V10 engine in an aircraft!)

It was a "Push-pull" design, rather than a pure pusher- but yeah, if it had been produced in sufficient numbers, it would have been a great aircraft.

It's well known that a pusher prop is more efficient I recall doing a centerline thrust endo on the old C337 many many years ago, on take off the rear engine pulled to idle almost guaranteed you where cooked where as the font donk pulled to idle you could sneak away, just,

I would imagine that if a “laminar flow fuselage” is your objective then a SE front prop would defeat the purpose.

It is a fascinating concept, but if it is ever to be anything more than a wealthy person’s private aircraft, what are the chances of the V12 piston gaining approval for SE commercial pax ops? They seem to have glossed over that little point on their website. They gloat about it’s efficiency, but fuel consumption is really only relevant to a high-hour commercial usage case. A private aircraft owner would be more concerned with the other costs of ownership.

Although they do mention freight, so it could be a competitor in that market, if it can fly around the clock and compete with something like the C208.

Something else irks me though. Entrepreneur aircraft designers having been trying to put pusher props on aircraft forever. None of them ever seem to succeed on a commercial scale. Now, I would be the last person to make that a reason to stymie innovation, but if I was the CEO of Fedex, I would still be pretty reluctant to hand over a large cheque for a couple of hundred of these as a launch customer.

So while it may look awesome on paper, and the prototype actually performs to specifications, and it’s an aeronautical engineer’s wet dream, will they actually sell any?

I have to agree on all counts.
I cannot see this ever coming to fruition other than a few prototypes to keep any investors content, for now!
It will however keep us entertained, for a while -)

Call me old-fashioned ... or more realistically a dinosaur ... but this Pro-Avia new design does remind me of a Shorts Skyvan. Maybe there are a few of those hanging around somewhere that might be revamped and brought back in to service?

Always good to see inovative ideas. With all that laminar flow, I wonder what the stall Characteristics
are like? You don't get owt for nowt in physics.

Reminds me of the Cirrus VK-30


https://cimg0.ibsrv.net/gimg/pprune....8680c09693.png

Pilots are taught to NOT stall now - so it won't be a problem. ;)

Checkboard, that Cirrus VK30 in your picture crashed on the 11th of february 2018. (NTSB ref WPR18FA088). A prop drive failure led, amongst other things, the prop to overspeed and contact the elevators. The pilot lost control in the subsequent in-flight break up.

According to my googling only 3 are still flying, so not entirely successful by any measure.

That was kinda my point. ;)