From: shauns@vice.ICO.TEK.COM (Shaun Simpkins)
Newsgroups: rec.aviation.homebuilt
Subject: Re: Popular Mechanics Article
Summary: the aircraft is the Discovery, out of Monterey, CA.
Date: 3 Oct 92 20:06:21 GMT
Distribution: na
Organization: Tektronix Inc., Beaverton, Or.

In article <1992Oct2.174105.4218@jhunix.hcf.jhu.edu>, crawford@jhunix.hcf.jhu.edu (James E Crawford) writes:
> 
> A few months ago, there was an article on homebuilt aircraft in Popular
> Mechanics. Among the aircraft profiled was a very futuristic-looking model
> with a rear mounted engine and front canards.

There were several Varieze-based ships in that article, such as the Berkut
and the Velocity.  Both are pure canards.  However, from your comments, it
sounds like you are describing the the Discovery, out of Monterey, CA..
It has been in
development for about 4 years and first flew 2 years ago.  It is unusual
in that the 3-surface configuration allows you to enter it much like you
would sit on a chaise lounge - that is, open the canopy, slide your
rear onto the seat, and pull your legs in and under the panel.  The luggage
compartment is very large.

I saw the prototype before it flew, and was impressed by the seating and
visibility.  The designers said that it wasn't intended to go terribly
fast or land on grass strips, but rather be a good cruising and
looking-at-the-scenery ship to be flown off of paved runways.
The info sheet they put out on it a while back seems to back that up -
with a 160 horse Lycoming, it manages about 140-150KT.  Compare that to
the Lancair 320's 180+KT and the RV-6A's 165KT.

Not too efficient, as you would expect with those double tails, bluff rear
body profile, and many wing-fuselage junctures causing drag.
Of more concern to me, however, is the very high landing speed of the
craft - I recall that it stalls at 61+KT.  This is because it doesn't
have any flaps, which is a consequence of the lift relationships that
have to be maintained between the canard and main wings to keep the ship
stable. 

The only flying example of a commercial 3-surface ship,
the Piaggio Avanti, has an extremely complex and lengthy flap extension
sequence which drops flaps on the canard, then the main wing, then the
canard in a carefully timed dance to keep lift balance and avoid pitch
change.  Such a system is too expensive for a homebuilt, so I guess the
Discovery just didn't include it.

Roncz had some relevant comments on 3-surface ships in his excellent
series of articles in the 1989-1990 Sport Aviation.  The gist of his
comments were that you can set up the 3 surfaces such that the plane
looks like more like a canard with the rear surface trimming, or more
like a conventional configuration with the canard surface trimming, or
a balance of the two.  The Discovery is more like the first, the
Piaggio an example of the second.  The advantages and disadvantages of
each configuration follow.

The 3-surface configuration looks like it is a good idea for the right
mission.  It makes sense on the Avanti since the designers wanted to
make an extremely efficient cabin-class aircraft with no wing spar
to intrude on the cabin.  They also wanted to maintain most of the
advantages of a conventional configuration, such as low landing speed.
The forward wing allowed them to move the spar back, and it was designed
such that the rear surface has all the pitch control responsibilities.

I'm not sure that it makes sense for a 2-seater.
My overall impression was that the designers went to a heck of a lot of
trouble to get easy entry and the engine out of their line of view.  In
the process they sacrificed efficiency, landing speed, and versatility.

I know nothing of the flying qualities of the Discovery, nor of the
solvency of the factory.  I'd be interested in hearing the opinions of
others who have flown the aircraft.


-- 
				Shaun Simpkins
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