Pusher prop…the way of the future ?

Elon Musk says we are nearly there; http://www.businessinsider.com/commercial-aircraft-in-2050-looks-brilliant-2014-11

You might be interested reading that interview with Ric Parker: Director of research and technology, Rolls Royce:

http://www.theengineer.co.uk/in-depth/interviews/ric-parker-director-of-research-and-technology-rolls-royce/1019368.article

There is an interesting part regarding new pusher prop engines being (re)envisioned for large airliners

Very nice reading !

There is also a firm named QinetiQ in the UK that has done outstanding work with solar powered remote controlled models.

Electric engines have one major advantage over jets and pistons….they produce less drag as they don’t breath air….and second….they can be placed where ever you want….since they are very lite in weight.

Here is the NASA Helios from 2004..it is the most remarkable aviation happening ( or phenomena even ) in the 21st centurys first decade; http://www.nasa.gov/centers/dryden/pdf/163836main_Helios_05_02.pdf

You might be interested reading that interview with Ric Parker: Director of research and technology, Rolls Royce:

http://www.theengineer.co.uk/in-depth/interviews/ric-parker-director-of-research-and-technology-rolls-royce/1019368.article

There is an interesting part regarding new pusher prop engines being (re)envisioned for large airliners

The noise is an issue at low level not altitude. Airport tend to be built on the ground and aircraft landing are usually pretty low…hence the nuisance.

I understand this but solar powered aerodynes seem to fly very slow at low and thus make no noise whatsoever. :highly_amused:

The noise is an issue at low level not altitude. Airport tend to be built on the ground and aircraft landing are usually pretty low…hence the nuisance.

Its not a case of propeller aircraft being concieved as loud but in this case the fact that pusher props make an annoying noise…somtimes loud noises can be pleasant . Its not a volume issue although that tend to be more noisey than tractor props.

If you have nine meter dia props they don’t even have to turn very fast to reach the speed of sound…and at high where Baumgarter and Eustace broke the speed of sound without an aeroplane there won’t be much of the sound either the air is so thin.

Pic from here; http://mesoslaunch.blogspot.fi/

Its not a case of propeller aircraft being concieved as loud but in this case the fact that pusher props make an annoying noise…somtimes loud noises can be pleasant . Its not a volume issue although that tend to be more noisey than tractor props.

Think of propellers and you might immediately conjure images of Indiana Jones, World War II flying aces and creaky crop dusters. Propeller-driven craft are often perceived as loud.

I predict a solar powered propeller plane will brake the speed of sound in level flight right about in the altitude on 40 km ( 132 000 ft ) in 10-20 years.

It has to be aerodynamically refined and big..very large and combo of the newest 40+ % efficient panels and 20+ % efficient panels that are now in the lab.

I have actually counted it is possible.

Surely the reason for pusher props not being majorly successful is the simplest one of all, in that airflow from a puller prop over control surfaces gives control before flying speed is reached, that was one of the main differences that pilots found when converting from piston engine fighters to the then new jets.

I am not possessed with the noise issue…but as for now I am with these; http://evworld.com/article.cfm?storyid=220

It says Helios went 170 mph ( Mach 0.25 ) at 98 000 ft using 24 kW…and it is a solar powered craft ( 930 kg / 300 kg payload ).

How fast could they go if you have 2335 m2 and thus 1030 kW max out put ( at high altitude round about noon ) with todays solar panels ?

I estimate 500 km/h with pusher props at really high !

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John Stringfellow was a pusher type plane fore runner; http://www.ctie.monash.edu.au/hargrave/stringfellow.html

The noise issue on many pushers is apparently a function of the prop ‘chopping-up’ the exhaust stream.

Moggy

it’s known for ages, but if it isn’t used in commercial aviation, it’s mostly because of high noise levels and lower operational altitude and top speed… at some point, you just can’t go any faster as your propeller looses efficiency when speed increases. That’s why most commercial aircraft use turbofans, where the fan provides thrust on take off (very high level of static thrust) and as altitude and speed increase, the “turbojet part of the engine” takes over as it is the only way to get sufficient thrust to go high and fast enough for long flights

for relatively short flights, the trade off can be acceptable, but do it with a transatlantic flight for example, and you’ll get delays counted in hours for a single flight.

The unducted fan seemed to have fail due to the very high noise levels. There was a MD-80 and a Boeing 727 with one fitted…the MD-90 was originally going to be the -80 series with UDF.

The UDF was louder than the remaining jet engines. The UDF BN Islander was soon converted to conventional engines.

There was the Optica and that buzzed around like an angry bee

LZ129 also had pusher props.

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Discussion; https://uk.answers.yahoo.com/question/index?qid=20110605122812AAYKi7G

Also the FLYER !

The unducted fan seemed to have fail due to the very high noise levels. There was a MD-80 and a Boeing 727 with one fitted…the MD-90 was originally going to be the -80 series with UDF.

The UDF was louder than the remaining jet engines. The UDF BN Islander was soon converted to conventional engines.

There was the Optica and that buzzed around like an angry bee

One problem with the Avanti is it is very irritating noise wise.

200 and something built since early 199’s is not particularly successful.

The Piaggio P.180 Avanti is a pusher prop and seems to be successful, there’s a fair number of them flying and it’s still in production so far as I know.

Does anyone know if any companies out there are still experimenting with unducted fan engines, or was that just a fad that died quietly?

Don’t forget the push pull Voyager..it flew at take off with only 0.041 kW/hp power to weight ratio…and made it around the world.

Also B-36 Peacemaker was a pusher prop design.

errr….make that 0.041 kW/kg ! Sorry folks !

The Vari-Eze and Long Ez have a pusher prop. Piaggio did it with the P.166 and of course the Convair B-36. Every now and then it crops up but never catches on.

Don’t forget the push pull Voyager..it flew at take off with only 0.041 kW/hp power to weight ratio…and made it around the world.

Also B-36 Peacemaker was a pusher prop design.

The Vari-Eze and Long Ez have a pusher prop. Piaggio did it with the P.166 and of course the Convair B-36. Every now and then it crops up but never catches on.

Interesting, I wonder if we will see those kind of planes in our lifetime? Whenever a new design offers a radical improvement of some or other characteristic, it is immediately suppressed.

Right….I think Burnelli was onto something. He seemed to have also convinced Chalmers “SLICK ” Goodling the test pilot from THE RIGHT STUFF even !

https://www.youtube.com/watch?v=u49_CrFqBh8