rgburrill

In any MANUFACTURER developing a turbofan. I have searched the records and found articles on turbofans dating back 9 years or so. I have seen some great photos and vidoes of work done. But these are all hobbyists, not manufactureres. There are turbine helicopter enginers and turboprops but I can't find a production turbofan. What is holding up the development? I know there are a large percentage of you who like the sound of a turbine but really, very few full size aircraft use turbojets anymore. And it's not only for sound control - turbofans are considerably more efficient.

So is it sound? That same argument is what people use to justify the extra expense of a 4 stroke piston engine even though from a sound point, 2 strokes are more accurate, especially with V-12s and Double Wasp engines. Or is it the idea that a turbofan is essentialy just an expensive ducted fan or electric fanjet? Or is there a technical reason? Or possibly a patent issue?

KC36330

IIRC Wren has one in the makings.

HarryC

My Feedback: (1)

Wren has shown a development version flying but it is not quite the type of turbofan you are thinking of. What they have done is mount a carbon fibre edf fan onto a geared down shaft coming out of the back rather than the front of a Wren 44, and then have to route the hot exhaust out sideways to clear the fan. iirc it is reported to develop around 20lbs of thrust, the core Wren 44 produces 10lbs thrust as a pure jet. It would have limited sales, because while it would suit the twin boom, externally mounted engine type of model that it was demonstrated on, it would not be practical in a model with the engine in the middle as almost all scale models are because you have two separate hot exhausts either side of the fan to be dealt with. Perhaps they are using it just as a test bed, demonstrator etc to gauge reaction. Reaction ought to be very encouraging because you suddenly get 90N thrust class with 45N class fuel load, but it does need to be reversed to put the fan infront in order to deal with the exhaust problem, and that would demand a redesign of the engine compressor to cope with the new flow off the fan etc, and then the drag of the fan efflux over the core motor would reduce the net thrust and so on.

See http://www.youtube.com/watch?v=fIiuSHSzf_Q

H

Dr Honda

My Feedback: (4)

I'm sure they would sell... but there would be a significant price hike. Then there is the question of... "Will I buy an engine for $5000, when I can get one for $3000 that will work?" As above... the Wren 44 fan is cool, but is only good for a Boomer type model... and for a fan to be feasible (Profitable) in the RC world, they will need to have some benefit. (low fuel consumption, less weight for the thrust, ect)

Just my 2 cents.

marc s

One of the European turbine manufacturers is developing one, I have been told its possible that it might appear during 2012.
I am not able to divulge names but it will be stunning, powerful and very fuel efficient.

marcs

dav.ie

My Feedback: (1)

And then there is this one:

http://www.youtube.com/watch?v=OJl7D...eature=related

marc s

That's the one being developed by 'Pegasus' for his incredible VTOL harrier project.

marcs

dav.ie

My Feedback: (1)

and . . . . . .


http://www.youtube.com/watch?feature...aK6ti5BM8&NR=1

rgburrill

Now this is a turbofan. Does it, or a similar, smaller design have hobby value?

rgburrill

Certainly they would be more but considering that you would get considerably more(perhaps double) thrust you could start with a smaller base engine. Then there is the fuel cost savings. I saw something (and can't find it now) about someone starting with a 20lb thrust turbine and creating a 40lb thrust turbofan. Thrust to weight ratio was incredible. And fuel consumption was cut nearly in half.