Der Nurflügelkanal - The Flying Wing Channel

[Hawaii Sloper]

Here we have the Genesisi 2 - a beautiful 'almost pure' flying wing...well its got that little tissue of a Horizontal stab perched on top of the fin...but...

I know this has been modelled several times but I'm not sure of the results.

One thing it does illustrate - in the hunt for stability with flying wings there are three main variations:

1. Swept back - probably the most common variation with stability in flight quite easy to achieve.
2. Non - or very slightly swept plank - probably second most common variation - but one of the hardest to get right interms of stability.
3. The swept forward configuration - oddly stability with this planform is not hard to achieve but many people think it looks a bit weird so they tend to shy away.

IF and its a BIG IF you can get the geometry and aerofoils right to achieve the amount of stability needed i.e. not longitudinally over-stable as some lower aspect ratio swept wings (Forwards or backwards) can be, then the plank planform will be the fastest and most efficient. But...its really not that easy to get it all right and working together.

More thought and experimentation is needed.

Doc.View attachment 14656View attachment 14657

Looks like @thenated0g mini solius "Plank" build.

Multiplex Mini Solius --> RC Conversion

It is around the middle of the wing. Don't recall the exact position, but it is on the spar in the above pics..

forum.alofthobbies.com

 

[Doc J]

Now...is this a flying wing? I'm not to sure but it is packed full of innovation - that is for sure.

LOVE those finney thingies...

The wings on this drone are almst identical in lift distribution to my Spada model.

Doc.

 

[Red]

I would say no. The tails are really a V tail disguised as fins. They provide pitch and yaw control. Interesting looking airplane though.

 

[Wayne]

Yep - V-tail but interesting. Have not seen that done before. I guess their goal here was drag reduction when using a pusher prop for better optics.

 

[thenated0g]

 

[Doc J]

Woo...thanks Nate! That's an eye-opener.
I think this is a crude version of the BSLD, as you can see the elevons are quite twisted. But its a 'real' plank (No sweep or wing tapers) and so the CG and the MAC are very close together and that makes it really sensitive to CG/Trim. Probably the elevator controls are bit too much, and those square tips are not helping either. But...just a few mods here and there and it would be really quite nice.

LOVE the cardboard construction - ideal fast and cheap way to prove a theory - or not.

Doc.

 

[Doc J]

Yep - V-tail but interesting. Have not seen that done before. I guess their goal here was drag reduction when using a pusher prop for better optics.

There is another point there actually.

Those inward-facing Fins...Tails...? "Tins"..."Fails:...? actually follow a similar practice used on the Predator drone of an INVERTED V so that any sideways influence, a gust etc, pitches the rear end of the airframe down and away from the source and creates a nose-up component that is quickly stabilized, rather than the conventional V-tail which would create a nose-down component and possibly a spiral to earth. This can happen to any aircraft that has an intrinsic static directional stability that is strong when compared to its diheral, in maintaining lateral equilibrium.

Normally this would not affect a drone that is linked and under control. But drones lose link very often, and this is exacerbated by the distance between the pilot or control and the aircraft itself. Today its perfectly normal to have drones operating over middle eastern regions under real-time control from Arizona, or similar long distances. If the link is lost for too long the nose of the aircraft can turn inwards and downwards can make the drone begin to spiral down to earth and crash. This has happened many times with vertical V-Tailed drones that have lost link for some minutes, and can be irrecoverable or cause breakup due to exceeding max speed.

Now lets dispel a myth:

Described above is what is termed "Spiral Instability" - Note: IN-Stability - and only occurs when normally stable aircraft originally flying a straight course has become influenced by an unplanned force such as a large gust or side wind and where no control inputs (Lost link) have been applied to correct the resulting turn, thus leading to a spiral which can become steadily worse.
Note that this effect would not be observed unless it happened to an aircaft that had been flying uncontrolled for quite a long time - probably some minutes - therefore it has absolutely no application whatsoever to our models.

There is no term "Spiral Stabilty" though I have seen it often mentioned here, so to me it sounds a bit more like the effects of too much Jim beam than anything aerodynamic.

Cheers,

Doc.

 

[jure]

I thought that the inverted V was adopted for proverse yaw.

 

[Doc J]

I thought that the inverted V was adopted for proverse yaw.

Another advantage, in fact almost the same thing, Jure. I think I covered it in the Aerodynamics channel one time?

But oh those landings....

Doc.

 

[Doc J]

Here is some interesting stuff about the history of the flying wing:

History of the Flying Wing - Aviation History - Century of Flight

History of the British Flying Wing The tailless aircraft concept was present in Britain throughout World War II, and many of the designs came from Handley Page, Armstrong Whitworth, General Aircraft Ltd., and de Havilland. The Handley Page Manx was designed by Dr. Gustav V. Lachman, and it had a...

www.century-of-flight.net

Doc