Facet Opel

Kind of late in the game on this thread, but thought I would throw in an idea I've played with to see what you all think. Take the basic plank or tapered flying wing with verticals out by the tips as has been discussed, but add small horizontal stabilizers out past the tips. I've attached a sketch of the Opel with this superimposed to give you an idea of what I'm talking about.
The models I played with awhile back seemed to fly alright, except I found that if the verticals were on the small size you could induce a weird yawing tumble with a hard rudder doublet.
I played with this because I thought you could have the basic benefits of a plank, but with a bit wider cg range. But in reality I just thought it might be fun.

Dave

That’s called a scissor tail, Dave. Blohm und Voss had a bunch of planes with them on the drawing boards at the end of WWII. Generally they’re moderately low AR swept wings but the little Skoda-Kauba that they used as a test vehicle had straight wings. Some of the B&V designs have been modeled and seem to fly pretty well.

Rutan's SpaceShipOne was also a scissor tail. Flew quite nicely, especially in glider mode.

I have seen some of those planes on the website, but dang they sure were going out on a limb with some of those weren't they!

I guess I really didn't consider Spaceship One because in my mind the tail on it is fully separated from the wing by the twin booms and not more of an extension of the wing tip.

The "additional pitch control" surface was also used on the "Zimmer Skimmer" and the later variant, the XFSU-1, pic attached, as well as other aircraft.

Originally Posted by orion

One minor little correction (and it may nor really apply here but FYI): A bi-convex section classically refers to a simple airfoil shape that consists of two circular arcs (top and bottom), either joined at two sharp points fore and aft, or joined at a point at the aft end and simple small radius at the front.

A convex airfoil uses an arc on the top surface and a flat line on the bottom. The terminology is often used in the design of supersonic wings, usually in the preliminary design stages where you are working at defining the basic planform and a baseline structure. The bi-convex geometry can be easily adjusted (radius of arc) to deliver a variety of structural depths without significantly affecting the performance aspects of the projects.

The biconvex design works well since in the transonic and supersonic regions you're really not interested in any particular camber line, short of an eventual certain level of refinement of the root to tip distribution.

The Facet seems to use a more conventional symmetrical section with a forward shifted maximum thickness. The maximum thickness of a biconvex section is always at 50%.

If the bi-convex section has a radiused leading edge, then the maximum thickness will be AHEAD of the 50% chord position.

In the field of applications I mentioned above, the typical use of bi-convex section is for high speed aircraft and so the leading edge is always assumed to be sharp.

I am good friends with the great Tom Cadet the builder of the Boorabee here in aus knows a bit about the Opel. Also I have about 15 mins of footage with the opel flying.

I am either going to bring the opel back to life or build a very similar design and complete scotts adventures

AIRSPEED IS LIFE!

That would be cool! Any chance of converting a bit of the video to an Internet usable format?

I second Orion's sentiments. I have always admired the aircraft and Scotts abilities and dreams. Good luck and keep us all posted.

Dave

Hi Guys, Long time no see.
I remember this thread from some time back, and have just come across some video footage of the OPEL on youtube, possibly put up by lowinnertia
This was actually a promo clip done to try and attract sponsors.
Scott is seen starting and getting into the OPEL, the narration is by someone else.
Here's the

LINK

LINK
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.
Arthur.

Wow, thanks for posting that! It's the first video of the aircraft I've seen. That's the first good look I've had at the landing gear, for one, and it's really neat to see the airplane in flight.

This is an overall design that deserves some more attention, IMHO. Obviously the original had a few flaws, as we discussed earlier, but overall it really seems like a nice little sportplane.

Originally Posted by Macboffin

The "additional pitch control" surface was also used on the "Zimmer Skimmer" and the later variant, the XFSU-1, pic attached, as well as other aircraft.

The XF5U-1 never flew, but the V-173 (Flapjack, Zimmer Skimmer, et al) did (was even flown by Charles Lindburgh). Here are a couple of photos:



Bruce

Bruce..... pictures like that make me smile. To this day, I still think that one of the most profound things I ever heard was an author who wrote something to the effect of, "you must remember that, back then, they didn't know what an airplane was supposed to look like..."

It's like looking at the flying boat with 8(?) wings that never made it into the air. It just reminds me that there was a time that everything was open.... And looking at those flapjacks, it's same thing... just to think.. there we were in the 1950's, on the cusp of the jet age... and we still didn't know what a prop-driven airplane was supposed to look like!

Seriously, they're really cool. I get a kick out of it every time I see them.

THANK YOU, ARTHUR !