No longer construction time. Economical use. Superb look and
typical tandem stability. What could go wrong? Well ... euh ...
things did go wrong. Just like in the history of Henri Mignet,
accidents did happen.
A very steep and uncontrollable dive!
The reason was the front wing. The airfoil (GU25) for the front
wing came from the model builder world. Burt rutan searched for
good airfoils for his design. He found none that did the job. Let's
say ... he found no airfoil with complete test data in the
performance area he was looking. So he had to search in those
airfoils that had complete test data and he choose the best ... of
the available. At that time no better job could have been done. But
the airfoil he choose didn't like deformations. Raindrops or bugs
on the front leading edge spoiled the perfect airflow over the
wing. the needed lift could not be reached and the airplane lost
its balance in lift forces. Normally you trim a airplane in such a
case. But even with trim the balance was lost. The airplane started
to dive!
The solution to the dive problem.
Owen Strawn from the Raptor-builder Yahoo-group mentioned the
given solution.
" So Rutan asked Roncz to develop a better canard airfoil, and
the new airfoil was used to retrofit the VariEzes (I believe
Quickie and Q2/200 [ed.: you will see this model later on this
page] are now using a different airfoil altogether [ed.: That is
true, they mention the use of LS1 at http://www.quickiebuilders.org
]. The Roncz airfoil produces greater lift than the GU25, with
lower drag, and is relatively insensitive to surface issues. It is
a great design, specifically tailored for canard/tandem use, but
until now nobody has ever gotten around to doing the engineering
required to adapt it to the Dragonfly."
The Dragonfly-guys found another solution to the problem.
When you look at the specifications, you see the small wing
area, the high wing loading and the resulting higher speeds. Also a
higher landing speed. OK, the stall speed is only 53 mph. But you
need to know that it is advised to land these kind of airplanes not
near the stall speed. You note that, when you look at the
difference between takeoff distance and landing distance. I
really wonder if these airplanes are for beginner pilots. The
higher the landing speed, the more experienced you need to be to
land (without missing the airstrip).
Best not your first airplane.
Several readers confirmed that the Quickie and its look-alikes
are not for beginner pilots.
Landings go fast.
Another problem I read in a French article by François Besse in
VOL MOTEUR is that the Dragonfly is too smooth. "Huh?", I hear you
say. Yes, the smooth lines make the Dragonfly and Quickie having a
low drag. If you are making a circuit preparing yourself for
landings, it is hard to slow down the airplane. Simply reducing
power is not enough. The Dragonfly simply keeps cutting itself
through the air. You need to land these airplanes in a very flat
approach.
Idea of me
I was wondering ... would a splitting tail be a solution to that
problem? It is used sometimes in gliders to reduce the speed before
landing. I guess it wouldn't be so hard to retrofit this system in
a existing Dragonfly or Quickie.
Euh...please, don't think that I was to say that the Quickie or
its look-alikes are bad airplanes. THEY ARE NOT! I just want
to say that if you choose to fly a Quickie or Dragonfly, you know
what you get. The good stuff and the bad. And as last bad thing I
want to mention that the Dragonfly (Mk I was mentioned in the
article) and the Quickie are known to need a long airstrip
(preferably a hard strip (don't know the right English word)).
But if you can live with the high landing speed and the long
airstrips needed, then you have a super airplane designed for fun.
It is rather easy to make (the most time taking job is the finish),
it is fun to fly (very stable) and it is very economical (low fuel
and oil consumption).
Lets say that if you learned to fly with a Flying Flea (which is
designed for beginners) and you want to grow up to a faster
airplane, this might be a perfect airplane for you.