what's old is new again ...

[rb1957]

from flight ...
Embraer tweaks turboprop concept to have aft-mounted engines ...

didn't Boeing try this in the 90s ?

another day in paradise, or is paradise one day closer ?

 

[IRstuff]

There were some combo planes that had both wing mounted and tail engines; DC-10 and L-1011 come to mind

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[MintJulep]

And then there is this:

https://www.youtube.com/watch?v=AraV2kvytIY

 

[3DDave]

Looks like a harmless polyp. Simple to remove and send off to see if it is benign.

 

[rb1957]

no, that's a testbed (by honeywell (and probably PWC) it looks like) ... for developing the engine software and performance.

another day in paradise, or is paradise one day closer ?

 

[Stephan Nelle]

This is the old version:

https://historicalcenter.embraer.com/global/en/cba-123-vector

 

[3DDave]

Ahh, an answer to the question "What's the vector, Victor?"

 

[Ng2020]

If nothing else, it complicates ground support access between the wing trailing edge and the props.

From the state of the wing, it looks like a very low maturity concept still.

 

[SWComposites]

rb - yes, Boeing had a concept like this in the late ‘80s, the 7J7. Fuel prices dropped and there was no market for this, so it was abandoned.

 

[LittleInch]

Bit of a thin looking wing in that top photo.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[rb1957]

I thought one reason Boeing dropped it was that the prop didn't like being in the wing downwash ?

another day in paradise, or is paradise one day closer ?

 

[LittleInch]

Maybe they should be mounted on top of the tail then?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[rb1957]

why not on the wing, as the great designer intended ?

another day in paradise, or is paradise one day closer ?

 

[WKTaylor]

Ahhh... the Ultrahigh By-Pass Un-Ducted Fan engines... lovingly known as the 'screamers'.

Regards, Wil Taylor
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o We believe to be true what we prefer to be true. [Unknown]
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[Lou Scannon]

Ahhh... the Ultrahigh By-Pass Un-Ducted Fan engines... lovingly known as the 'screamers'.

That's my recollection why they didn't catch on at the time.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[jaceb]

Flight tests of the UDF has been put on hold because of the fact that acoustic pressure was so high that cracks has started build up in the FTB's fuselage structure almost instantly. This is why GE inside assessment for this was "no go" for the direct drive fan type. Right now what is worked with Safran this is geared version - from practical standpoint this is just large turboprop with fancy looking fixed-pitch propeller. I think reducing blades number and adding PCM will be next step (just matter of time and xxx mln of USD)- this way GE/Safran will close the loop and will reach conclusion that turboprop is most efficient form of turbine propulsion (kind of discovery isn't it?).

 

[rb1957]

really ? a fixed pitch prop ? didn't they go out in the '30s ?

another day in paradise, or is paradise one day closer ?

 

[jaceb]

yes - simply is spinning much faster than standard propeller but still slower than original UDF- if you have seen pictures they have added additional fixed blades behind propeller for tuning down noise - child of CFD analysis

 

[MintJulep]

What problem is this aircraft trying to solve?

 

[rb1957]

those blades look variable pitch ?

If the blades spin faster than normal turboprop, are the tips supersonic ??

"What problem is this aircraft trying to solve?" ... I don't know ... maybe a solution looking for a problem ? I suspect it's a marketing solution to a future problem.

another day in paradise, or is paradise one day closer ?