Quantcast

Small single seat 3 surface concept

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

Wild Bill

Well-Known Member
Joined
Dec 11, 2013
Messages
86
Location
Vidalia, GA
Fulcona
You have any more info on that design of Burt’s? I must have missed that one somehow.

@daveklingler
The 500 lb weight figure is takeoff weight with pilot and fuel.
I’ve seen I think one of those Eagle 150’s down at SunNFun.
I’ve always wondered how they flew and what kind of real world performance numbers it offers.
I remember that the fuel tank is aft of CG. It takes off tail heavy and lands nose heavy.
 

ScaleBirdsPaul

Active Member
Joined
Jul 6, 2015
Messages
40
Location
Connecticut
Wow that Rutan design is almost exactly what I had in mind with the 3-surface concept in my avatar. I would have gone with a narrower fore wing for better ground control though, so it wouldn’t be a true tandem 3-surface.

I like your concept a lot Wild Bill, definitely striking!
 

Victor Bravo

Well-Known Member
Joined
Jul 30, 2014
Messages
7,774
Location
KWHP, Los Angeles CA, USA
I don't think the Amsoil racer was a three surface aircraft. It was a tandem wing "quickie" derivative, and they wanted to race it in the biplane class at Reno. So they added a "tail", which made the airplane meet the rules for a biplane... but aerodynamically it wasn't a biplane and it wasn't a three surface airplane. Kinda like one of those "female" Russian Olympic athletes in the 1960's that you wouldn't want to run into in a dark alley.
 

fulcona

Active Member
Joined
Dec 20, 2004
Messages
29
Unfortunately the August 1987 Popular Mechanics article did go into much detail about the airframe other than what is obvious in the picture. It was more concerned about advancements in avionics such as fly by wire controls and the use of a HUD. The modern EFIS systems have already surpassed those talked about in the article. ( they mentioned LORAN) . The only airframe comments were about engines that supposedly under development by John Deere which never materialize, small props for ground clearance and less asymmetrical thrust with an engine out, staggered seating to lower fuselage width and sailplane type landing gear because that is all that is needed to keep the props off the ground. Outrigger wheels on the wingtips helped keep the plane level. Wally Schirra and Frank Christensen were also in on the design. Too bad one was never built. It was an effort to design a “Piper Cub” for the next generation.
 

ghostrider

Member
Joined
Jan 29, 2010
Messages
10
Location
Lombardia, Italy
I think the concept definately shows promise as is evidenced by the Avanti. Obviously this is a highly optimised commercially produced airframe. It provides close jet performance with prop fuel flow. Cited from Piaggio´s PR department so it has to be true. My very limited research on the topic shows one or two noteworthy advantages outside purely performance orientaded ones.

1. Safety. 3(L)S designs (as has been noted before) can be made very difficult to stall. In theory and all else being equal, just a higher aspect ratio of the canard should make it stall before the main wing, providing obvious safety implications.

2. Ease of operation. Linking flap operation between the main wing and the canard can cancel out the trim change when going up or down with the flaps. Pitch changes but trim does not. It should be quite and interesting experience to see the nose of the aircraft go 10 deg lower with no change in stick force, when going for one notch of flaps. Almost as with FBW.

3. Again, ease of operation. 3(L)S designs can quite easily be designed so that they are trimmed for a speed, no matter the throttle setting. This means that maintaining speed for optimal glide / safe margin to stall is simplified. Just trim it and maintain glide slope with trottle. Basically means that once trimmed flying a standard approach is a 2 dimensional operation. One does not have to concern onself with pitch control. Throttle and roll is all it takes to get the plane to the threshold.

The incarnation of the concept that I would love would be a two seat tandem tractor design with a T-tail. I did check the viability in X-plane and we all know its limitations, but I think it shows potential. X-plane seems to think that what I designed gives me 1 kt per hp (within reason, I chose 250) and a factor of 4.7 max level/stall speed. Better than RV8 at least. Can certainly be improved upon with optimisation of which I have done next to nothing. I know, I know... One can make an RV 8 go supersonic in X-plane... but still.
 

fulcona

Active Member
Joined
Dec 20, 2004
Messages
29
I often think of what I deem “out of the box” ideas and finally I see others think like me. I had wondered,too, if drag plates would be a good idea.

About a thousand years ago I built and flew a single place Quickie. Neat little airplane and had a lot of fun with it. So on the basis of that design, you can deduce approximate performance and weight of a similar aircraft. Empty weight SHOULD have been around 248 lbs. if memory serves me correctly. (Mine wasn’t). Engine weight was 78 lbs. leaving 170 lbs. for the airframe. Engine and fuel weight is 126 lbs. Not a lot of weight to be saved on an airframe of a plane of that type, but Michael Columban (sp) did it with the Cri Cri. Love Wild Bill’s design. Everyone always says not to mess with modifications to canard designs unless you really know what you’re doing. Good advice. But I’ve never seen where to go for good advice if you need it on such a design. Never seen anyone offer the design advice either. Maybe for good reason. It would be great to have a design as Wild Bill’s if we could get some professional help. With advancements in battery technology the twin electric engines would be really nice. Especially with no change of CG due to fuel burnoff.
 

Wild Bill

Well-Known Member
Joined
Dec 11, 2013
Messages
86
Location
Vidalia, GA
I’ve always been somewhat drawn to unconventional airplanes. The EZ type canards just have such a cool ramp appeal factor. Even if they aren’t a perfect aerodynamic success.
But really, performance numbers for the vari/long EZ are good compared to other aircraft. The downside is no flaps.
Back when I bought my varieze I was also looking at the lancair 235, and RV-4. And also possible considering something like a Mooney.
In the end the lancair was not dramatically better, performance wise. And even with flaps it could eat up some runway.
The benefit of the RV was mainly short field grass runway. Otherwise it was not that great.
The Vari ended up fitting the mission of flying long cross country at altitude, and was far more affordable than anything else.
Once I learned how to fly it I could do ok on short runways. I got in several airports with runways in the 2200-2600’ range.

I think where some new canard designs go wrong is not loading the canard heavily enough.
This would be a somewhat complex little plane to design and construct. With two engines/motors, retractable gear, and the T tail.
I don’t know a good way to build a T tail that isn’t weak or heavy, or worse, both.

Every time I watch the test model fly I get excited. I’ve daydreamed numerous times about making a surprise visit to one of breakfast club fly ins in this thing.
If I were younger and more enthusiastic about it with what I know now, I would be really busy trying to make it happen.
I know at least one aeronautical engineer I could have possibly convinced to help on some things.
Youth is wasted on the young....
 
Top