Flaps on delta wing + canard configuration?

[BerserkCol]

Good Night

 

I'm new over here however i have been following this community since long time.

 

I'm a young aeronautic engineer, with experience in structures and preliminary design (in conventional configurations), now I’m designing my own plane, she is a delta wing configuration + canards on the nose, for that I’m want to know if this configuration could have flaps + slats.

 

The question is because I know that the delta wings couldn't have flaps, for the nose down moment, however with the canards I thing that I can recover the control over the plane and make a stable design, is that right???

 

the design is similar (in size) to rutan's varieze however is more like a rafale or eurofighter.

 

Thanks a lot for your help

 

BerserkCol

[Richard Schubert]

Google

"rutan variviggen"

[Waiter]

The VariViggan I flew had these, I think it was called "reflex".

 

It would lower the both ailerons the same amount to act like flaps.

 

Waiter

[chasingmars]

I'm a young aeronautic engineer, with experience in structures and preliminary design (in conventional configurations), now I’m designing my own plane, she is a delta wing configuration + canards on the nose, for that I’m want to know if this configuration could have flaps + slats.

 

The question is because I know that the delta wings couldn't have flaps, for the nose down moment, however with the canards I thing that I can recover the control over the plane and make a stable design, is that right???

 

There have been delta types, and even flying wings, with flaps of a fashion, the key concern is, as you said, the pitch moment they induce. The Me263 Komet from WWII had a type of trailing edge split flap that produced very little moment change on the flying wing for example.

 

With the canard however, bear in mind that you're trying to reduce stall speed. If you are intending to keep the canard-first stall characteristics (and if not, you have to tackle the deep stall recovery issue), then flaps, due to causing a nose down moment on the main wing, actually increase canard loading for any given angle of attack. This means you will actually need a somewhat greater elevator deflection to keep the canard flying, and this will actually make your canard stall a bit earlier as you run out of elevator deflection, meaning the flaps are effectively useless, unless you also flap the canard. The Roncz canard elevator is essentially a flap, so one way to do this might be to allow increased elevator deflection with flaps extended. Not the simpliest stability problem, but theoretically possible. Slats could help, as they tend to simply extend the lift/AoA curve to a higher AoA at stall (unlike flaps which tend to shift the whole curve up), but again, you'd have to make sure that the canard could remain flying at the higher AoA to ensure it doesn't become the limiting factor. Interestingly, this implies that fixed slats on the main wing could be a possible way to deal with deep stall by ensuring lots of AoA margin on the main wing but for a Cozy/Long type aircraft the performance penalty in drag is probably untenable.

 

This assumes you're using the canard as a proper full flight surface. Many canards on big delta wing style military aircraft use the canards basically as a control surface and to modify the vorticies over the main wing (like LEXs do), and so are a different kettle of fish.