My XV1 Vortex

[EdwardA]

I know some of you may say this belongs in an RC forum, but with my background, I have a very different mindset and purpose for building this than most model builders. I thought the people here probably think more similarly the way I do. My purpose is strictly research.

I'm not trying to get in aerodynamic theory arguments. This is something I thought of in 1991 and now determined to investigate in my retirement. This is what I'm trying to do. My configuration puts the forward wing's.....wing-tip vortices directly into the ducted fan spinning in the same direction. What I"m hoping is the vortices will be elongated and move towards each other in some regard, producing a narrower wake behind the aircraft. I can't say that's good or bad. I plan to build a small wind tunnel and have a look.

 

[riggerrob]

Clever thoughts.
Many discarded ideas were just too far ahead of their times in terms of materials or computational fluid dynamics. IOW Some of those old ideas are just waiting for new materials or new computation methods to make them practical.

Go watch the youtube segments by Barnaby Wainfain on "The Seven Deadly Sins of Airplane Design." or "Low Aspect Ratio."
Wainfain's very low aspect ratio Facetmobile is so efficient because wing tip vortices collide behind the airplane and cancel each other out.

 

[EdwardA]

I wish I could, watch more video. I have to use my cell phone for internet, so I'm limited on data....and I upload a little myself, about this project.

Sorry, I've deleted videos for editing.

 

[EdwardA]

....Wainfain's very low aspect ratio Facetmobile is so efficient because wing tip vortices collide behind the airplane and cancel each other out.

I read the analysis. Interesting, but the manipulation of the vortices is not my only interest. A big part of my design is running the vortices thru the propulsion. That's not only a major difference but that and the configuration allows, maybe even promotes more powerful power plants. In '91 I designed it for turboprops with very curved propellers...something like Dowty makes, beyond my means. Trying to put propeller in the middle of a spiral shaped shroud is extremely problematic. I find though, that sometimes solutions work themselves out and end up being a plus.

My next step is building a small wind tunnel. I won't get a bunch of data like a sophisticated University, but I can smoke test and photograph the results.

More detail.

thefourthpoint.com

 

[EdwardA]

I've recently found interesting search terms; oval wing, ring wing, joined wing, closed wing.

My wing-tip is open. If it were closed, that would defeat my purpose.

 

[Prophet141]

This is all very interesting, has any progress been made?

 

[Nik]

My compliments on the neat design, EdwardA. I've saved the pic towards my Scifi stories...

Um, are jet engines commonly available in L/R-handed pairs to match those incoming vortices ??

Upper and lower wings' vertical separation is deceptive from that angle: looks like you do have enough gap for a 'high-bypass' cowling...

 

[riggerrob]

This is sort of an inverted version of a toroidal wing biplane.
Mind you toroidal wing has the front wing on top and channels wing tip vortices down-wards to cancel out vortices generated by the lower wing.
Toroidal wing has a strongly, elliptically, swept, leading edge coupled with a gently swept trailing edge to encourage vortices to migrate outboard ... similar to a Schumann planform.
Also look up recent developments in toroidal marine propellers.
Just like the original poster, toroidal wings are more clever thinking about ways to minimize the energy wasted by wing tip vortices.

 

[riggerrob]

" ... Um, are jet engines commonly available in L/R-handed pairs to match those incoming vortices ?? ... "

At those (a few thousand) rpms I doubt if direction of rotation makes much difference in how much airflow the engines will ingest.

 

[Allan511]

I wish I could, watch more video. I have to use my cell phone for internet, so I'm limited on data....and I upload a little myself, about this project.

Sorry, I've deleted videos for editing.

I've recently found interesting search terms; oval wing, ring wing, joined wing, closed wing.

My wing-tip is open. If it were closed, that would defeat my purpose.

Hello Edward.
Cool looking design.
Is there a propulsion system in the fuselage consisting of one or more engines?
I ask this because if the only propulsion systems are at the wing tips, the rudder is severely undersized. In the event of an engine failure the only option is to cut the good engine power significantly or spin in. Somewhere there is a post about reengiening the B52 with four engines instead of eight.
They would have to completely redo the vertical stab and rudder with extensive modifications to the aft fuselage to have acceptable engine out performance.
The fans should definitely turn in the opposite direction of the vortices to recover the energy.
One reason this type of energy recovery is hard to achieve is the narrow flight envelope for maximum capture.
Cross winds and different angles of attack will distort the vortices and affect the disc loading of the fan. This will reduce efficiency and lead to cyclical fatigue of the fan.
Your fans are very close behind the wing and that may mitigate this issue somewhat.
Cool take on this idea.
I hope you can make it work.

 

[EdwardA]

This is all very interesting, has any progress been made?

Sorry I haven't been back to update details. I let my website expire...an effort to get my budget in line. But this is a cashed image from bing, of the second version. I'm not sure if I had this one up or the first version that had the rear wings on top of the tail.

Putting the rear wings on the fuselage help solve a lot of issues. Ha, the rudder works fully, the wires to the motors are much shorter and the rudder linkage is typical instead of crazy.

I am building a third version before flying any. I'm not willing....if I destroy one on the maiden, not to have one whole, setting on my table. I'll never fly the only one I've got. Truely the first version was no more than a learning experience never meant to fly.

The big difference between the second version (shown) and third version I'm working on now is weight and size. I'll have 100 sq" more wing area and it's coming out lighter too.

The Wing Cubic Loading, WCL on the second model is 10.3, which isn't bad for a twin engine. The WCL on the third version will be about 8.5 to 9. That's really decent for a twin and will make it much easier to fly.

The second version which will fly first still needs a few changes; one, I want to mount the fuselage differently so it's easier to get on and off. Two, just more control surface programming. The Control Surface Programming is extremely important and I"m using both aileron and elevator on the front wing and a flap mode for take-off and landings. I'll have to make final decisions regarding those functions. The trick is to make them effective, but simple.

 

[EdwardA]

I wish I could, watch more video. I have to use my cell phone for internet, so I'm limited on data....and I upload a little myself, about this project.

Sorry, I've deleted videos for editing.

I've recently found interesting search terms; oval wing, ring wing, joined wing, closed wing.

My wing-tip is open. If it were closed, that would defeat my purpose.

Hello Edward.
Cool looking design.
Is there a propulsion system in the fuselage consisting of one or more engines?
I ask this because if the only propulsion systems are at the wing tips, the rudder is severely undersized. In the event of an engine failure the only option is to cut the good engine power significantly or spin in. Somewhere there is a post about reengiening the B52 with four engines instead of eight.
They would have to completely redo the vertical stab and rudder with extensive modifications to the aft fuselage to have acceptable engine out performance.
The fans should definitely turn in the opposite direction of the vortices to recover the energy.
One reason this type of energy recovery is hard to achieve is the narrow flight envelope for maximum capture.
Cross winds and different angles of attack will distort the vortices and affect the disc loading of the fan. This will reduce efficiency and lead to cyclical fatigue of the fan.
Your fans are very close behind the wing and that may mitigate this issue somewhat.
Cool take on this idea.
I hope you can make it work.

I've done a lot of testing of these ducted fans. They are probably the best EDFs money can buy. They're extraordinary matched too. I had considered a differential thrust controlled by a gyro. Not needed under normal conditions and the likelihood of one motor failing is very minor...at least until they're well used. If one motor did fail, the model would be destroyed. It is unlikely I'll fly these models much, just enough to get some video. If there ever was potintial to produce this for the public then development of a failsafe system would be needed. For a few short proof of concept flights it's not necessary. These EDFs are that good. The motor controllers are in the same league. I bought the best. I ruined a battery running the voltage down to the bottom several times during my testing.

 

[Nik]

Off-topic: I dabbled with R/C aircraft for a while. Spent a lonnnng Winter assembling a nice 'basic' kit, learning to cosset the glow-plug engine and its toxic fuel, the 27 MHz link, servos etc etc.
First and only outing, total lawn-dart...

 

[EdwardA]

Off-topic: I dabbled with R/C aircraft for a while. Spent a lonnnng Winter assembling a nice 'basic' kit, learning to cosset the glow-plug engine and its toxic fuel, the 27 MHz link, servos etc etc.
First and only outing, total lawn-dart...

The fuel never bothered me. I liked it. I guess I'm lucky. Scratch building is very different and sometimes it takes me 2-3 models to get optimum results. I spent a number of years ONLY building free-flight of my own design. I felt that was the best way to learn. They have to be really good or they won't stay in the air very long. One of my first free-flights had twin Cox 049s in push-pull configuration. The Cox engines could easily be started backwards after removing the wind spring.