what kind of plane is this?

[Graeme]

I keep reading the Miles M39 Libellula is a tandem wing aircraft - no mention of canards. Or are the terms interchangeable?

Tandem wing - Wikipedia

EDIT....

"A canard or "tail-first" configuration where the forward surface is much smaller and contributes primarily to control and/or stability.[1] "

 

[GrauGeist]

In Wiki's own words:
"The aerodynamics of the canard configuration are complex and require careful analysis."

Canard (aeronautics) - Wikipedia

 

[Odoaker]

In a canard, the horizontal stabilizer, being forward of the wing, the CoG, and the CoL, counters the pitch down tendency by generating positive lift, thereby relieving the wing of some of its load. This makes for a more efficient flying machine.

Theoretically, I understand everything you write. But if such planes are more efficient, why didn't everybody build planes this way during the First and Second World Wars? I don't believe the story that everyone wanted to "bypass" the Wright Brothers patent. During the war, no one cares about patent rights (and the Soviet Union didn't even care in peacetime).

Wiki: Static canard designs can have complex interactions in airflow between the canard and the main wing, leading to issues with stability and behaviour in the stall.

Well, now I don't understand anything. So this Canard gives better stability or worse?

 

[Marcel]

Theoretically, I understand everything you write. But if such planes are more efficient, why didn't everybody build planes this way during the First and Second World Wars? I don't believe the story that everyone wanted to "bypass" the Wright Brothers patent. During the war, no one cares about patent rights (and the Soviet Union didn't even care in peacetime).

Wiki: Static canard designs can have complex interactions in airflow between the canard and the main wing, leading to issues with stability and behaviour in the stall.

Well, now I don't understand anything. So this Canard gives better stability or worse?

A canard design is less stable. For the Wright brothers this might have had the advantage that they were even more aware of the importance of being able to steer on all axis.

 

[XBe02Drvr]

Well, now I don't understand anything. So this Canard gives better stability or worse?

As in everything else in aviation, the devil is in the details. Only a tiny fraction of the development effort in aviation over the years has been devoted to canards, so they are way behind conventional airplanes in terms of evolution.

 

[Odoaker]

Only a tiny fraction of the development effort in aviation over the years has been devoted to canards

Why If theoretically such machines are more efficient and defense from stalling themselves?

A canard design is less stable.

Gentlemen, work out one common version! XD

 

[XBe02Drvr]

Why If theoretically such machines are more efficient and defense from stalling themselves?



Gentlemen, work out one common version! XD

In this, as in all other aspects of life, there is seldom unanimous consensus. You only have to read a few threads on this forum to see that.
My understanding of your first question (and this is not to be taken as sacred fact), is that in the frenzied growth of aviation during WWI the conventional tractor biplane emerged as ruler of the skies over the battlefield, so that's where all the effort was concentrated for the next few decades. Most advances were evolutionary, rather than revolutionary like the Wright brothers, so the ever increasing body of knowledge allowed desirable improvements to be made with less effort and technological risk. Meanwhile, the basic guidelines of canard design were being laboriously toggled together by a few lonely "voices in the wilderness" in the face of ridicule from the mainstream. WWII brought a few halfhearted attempts at canard military planes, but under the pressure of wartime production demands, not enough effort and resources were available to bring them to success.
That's my take on it, but everybody here will have a different narrative.

 

[GrauGeist]

That's my take on it, but everybody here will have a different narrative

No, I agree.
Aircraft development, unlike the automobile, was accelerated due to it's martial value.
While there were some experiments, the main focus was on tried and proven arrangements until the jet age, because the time between concept and production was critical.
If it weren't for WWI and WWII, the technology of flight might have taken much longer to maturate.

 

[Odoaker]

in the frenzied growth of aviation during WWI the conventional tractor biplane emerged as ruler of the skies over the battlefield .

But why just such a construction, not a canard? I heard the theory that the radial engine was easier to cool when it was placed at the front. The front engine is the center of gravity in the front. So - tail on the back. You think this theory makes sense?

I also remember the conversation with the constructor of the EM-11. He said the push engine is always "less efficient" and this drawback of his plane is inevitable (but has other advantages, he says). But why is the rear propeller less efficient?

 

[pbehn]

No, I agree.
Aircraft development, unlike the automobile, was accelerated due to it's martial value.
While there were some experiments, the main focus was on tried and proven arrangements until the jet age, because the time between concept and production was critical.
If it weren't for WWI and WWII, the technology of flight might have taken much longer to maturate.

The plane in the OP was in answer to a request for new and novel ideas for flight. I think the front canard was to solve CoG issues on a flying wing bomber. It may have had some plus points but it had two accidents too.

 

[wuzak]

I also remember the conversation with the constructor of the EM-11. He said the push engine is always "less efficient" and this drawback of his plane is inevitable (but has other advantages, he says). But why is the rear propeller less efficient?

I suspect that the propeller in a pusher configuration is affected by the wake from the wing, in the example given, or from the structure of the aircraft.

The propeller may be less efficient, but the aircraft could still be more efficient. A tractor propeller affects the airflow over part of the wing, which can cause extra drag. A pusher prop allows the wing to work more efficiently.

When running on only one engine the Do 335 was faster as a pusher than it was as a tractor.

 

[XBe02Drvr]

When running on only one engine the Do 335 was faster as a pusher than it was as a tractor.

When running with the front engine shut down, the Cessna Skymaster overheated its rear engine.

 

[Odoaker]

When running on only one engine the Do 335 was faster as a pusher than it was as a tractor.

When running with the front engine shut down, the Cessna Skymaster overheated its rear engine.

Do 335 also had this problem with the rear engine. Even on a "normal" flight.

 

[swampyankee]

Theoretically, I understand everything you write. But if such planes are more efficient, why didn't everybody build planes this way during the First and Second World Wars? I don't believe the story that everyone wanted to "bypass" the Wright Brothers patent. During the war, no one cares about patent rights (and the Soviet Union didn't even care in peacetime).

Wiki: Static canard designs can have complex interactions in airflow between the canard and the main wing, leading to issues with stability and behaviour in the stall.

Well, now I don't understand anything. So this Canard gives better stability or worse?

One reason is that they're generally not more efficient. (see https://ntrs.nasa.gov/api/citations/19870013196/downloads/19870013196.pdf). Indeed, they may be less efficient as it's difficult to use flaps on the main wing. Trailing edge flaps increase nose-down pitching motion, so if the canard has enough authority to deal with the pitching moment due to flaps, it will be able to stall the main wing if the flaps are up, which would be a very bad thing. This means that canard aircraft need too much wing area for efficient high-speed performance. A second is that it's hard to get enough vertical fin area for yaw stability (this is why the VariEze and Beech Starship had swept wings. Neither is fast enough for sweep to be useful). Another problem, which isn't particularly aerodynamic, is that since the wing is behind the center of gravity, it's more difficult to find space for fuel and (for military aircraft) bombs.

Current military canard aircraft have a couple of advantages in this regard. First, efficiency is fairly low on the list of priorities for fighter/attack aircraft. Second, they have complex digital flight control systems which can manage the stability issues and prevent problems like stalling the main wing.

 

[swampyankee]

The Draken (AJ-37/J-37) was quite stable and didn't use computer controls at all. Of course, it flew as a delta with elevons, so the canard was essentially static.

The Viggen (AJ/JA/SK-37) was the canard aircraft; the Draken (J-35) was a low-aspect ratio double-delta

Draken: The SAAB 35 Draken

(image from By Stahlkocher - https://airdefense.bliss.army.mil, Public Domain, File:SAAB DRAKEN.png - Wikimedia Commons)

Viggen: The SAAB 37 Viggen

(By Alan Wilson - Saab AJS-37 Viggen '37098/ 52' (SE-DXN)Uploaded by High Contrast, CC BY-SA 2.0, File:Saab AJS-37 Viggen 37098 52 (SE-DXN) (9256079273).jpg - Wikimedia Commons)

 

[Admiral Beez]

Looks like its a Miles M39 Libellula. Initially designed with a potential to be used on Carriers but never went into production.

The wing fold would have been interesting to see. Perhaps the wings would fold forward towards the canards?

 

[pbehn]

The wing fold would have been interesting to see. Perhaps the wings would fold forward towards the canards?

The experimental carrier type looked like this

There was also a tandem wing Lysander like this, from here Westland P.12 Tandem "Wing" Lysander

 

[Admiral Beez]

The experimental carrier type looked like this
View attachment 603688

There was also a tandem wing Lysander like this, from here Westland P.12 Tandem "Wing" Lysander

View attachment 603690

Was the Lysander going to serve as COD? That seems the role for the Albacore.

One of my favourite what ifs for FAA special purposes aircraft is the Boulton Paul Sea Balliol fighter

 

[pbehn]

Was the Lysander going to serve as COD? That seems the role for the Albacore.

One of my favourite what ifs for FAA special purposes aircraft is the Boulton Paul Sea Balliol fighter

I don't know anything other than from wiki "P.12 Lysander Delanne (Unofficially referred to as the Westland Wendover)[24] Adaptation of a Lysander II as a turret fighter, its standard wing retained but with a twin tailed Delanne type rear wing and 4-gun Nash & Thompson power-operated tail gun turret replacing the empennage. It flew well but did not proceeded past trials with turret mock-up.[25]" I was just pointing out that not all of these planes are "canard" designs, tandem wings and Delanne wings are similar but different.

 

[Elvis]

The experimental carrier type looked like this
View attachment 603688

There was also a tandem wing Lysander like this, from here Westland P.12 Tandem "Wing" Lysander

View attachment 603690

Those remind me of Burt Rutan's old Quickie airplane.