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Story of a Model Aircraft Designer
By: Andrew S. Rosz
This is a story about an R/C Model Aircraft Designer, namely myself. As most of us in
the hobby quite routinely build a plane from a kit, or scratch build one from a plan, we
are usually met satisfactory results at the flying field with our new creation. But what
about the people in the hobby that take on the task of actually designing an aircraft
starting only with their imagination? After now having joined the ranks of these few
individuals by designing, building, testing, flying, and fine-tuning designs of my own, I
would like to share with you some of my experiences along the way. There is much that I
have learned.
Unlike a kit, there are no plans to go by. And with the particular designs and building
materials that I have chosen, there are no similar designs or existing patterns to use as
a guide; so every design detail is truly unique. One of my recently patented designs is a
40-size flying wing. This design was by far my most complicated design project I have
undertaken to date. To begin with, I wanted this design to emulate the B2 Stealth Bomber
so the obvious first step was to obtain photographs and/or pictures of the real plane. I
had no luck. I couldn’t find even one picture. Boy, we’re off to a good start
here... So, while at the Ft. Lauderdale Beach air show last year, I remembered that I had
taken a few photos of the real B2 as it did a slow fly-by over the beach; and that’s
all I had to go on. After about 20 hours on my CAD program, I realized that designing a
40-size scale B2 was completely out of the question. Logistically, the plane
shouldn’t fly. Nevertheless, I pressed on. After making about 100 mathematical
calculations concerning everything from the density and weights of the various parts based
on the materials I would be using, certain answers began to present themselves such as
appropriate wingspan, chord length, spar location, sizes of control surfaces, wing
loading, and center of gravity location. Mind you, design considerations of these items
for a wing aircraft is completely different and unlike that of a conventional aircraft. Up
to this point and like most other aircraft designers, I usually designed only
"normal" airplanes with a wing, fuselage, and a tail where all these aircraft
usually obey generally agreed-upon principles of aircraft design and aerodynamics. After
about another 50 hours or so on the drawing board, it was finally time to start cutting
out the pieces and building the plane. Then more problems; How do I attach the
fuselage?... Where should I place the CG?... What shape should the airfoil be?... How much
washout should there be?... Where should I place the wheels?...Having consulted several
"experts" on flying wings, it seemed that the only constant was that there was
no constant. So, despite many calculations, much was still left to my "best
guess."
One hundred building hours later, the plane was done and ready to fly. Problems solved
(so I thought), and the big day arrives... time for the first test flight... Radio...
check. Trims... check. Engine working OK... check. Rolls straight... check. Well, the only
thing left to do was to get it on the runway, push the throttle foreword, pull back on the
stick, and see what happens. And that’s exactly what I did. It rolled... and
rolled... and rolled... right off the edge of the runway. And right in front of about of
100 people eagerly awaiting the outcome of the first test flight. My heart sank. "Oh
shit" I thought... great... just great... this is great for my reputation not to
mention my ego. So I shamelessly went to retrieve my plane (no damage) to assess the
situation. After discussion with the "experts" witnessing the not-to-be historic
first flight, we all agreed that the position of the CG had to change. We made the change
and tried again. It rolled... and rolled... again, right off the edge of the runway, but
this time, it flew about 50 feet horizontally before coming to rest safely in the grass.
Again I thought, "Oh shit... now what should I do." After being so scientific
throughout the entire design process, I was now desperate for answers and thinking
"How the hell am I going to get this thing off the ground." After more
discussion with the "experts," we raised the nose a little, moved the wheels a
bit more forward, made some more trim adjustments to the elevator and ailerons, and moved
the position of the battery yet another time.
Let’s try it again. This time we were met with success. The plane lifted off
smoothly, trimmed out easily, and flew beautifully. Come time to land, descent was smooth,
flair and touchdown went flawlessly and the end of the first flight was met with
congratulations from no less than a dozen people. At this point, I knew that I had a
winner of a design. During the second test flight, I put it through some basic maneuvers
including loops, rolls, and slow flight. It handled exceptionally well and showed no
undesirable tendencies. This again was met with an incredible sigh of relief as well as
more compliments from the crowd. Knowing that I did not have to change or modify the basic
design was truly a miracle; that is, I got it right the first time. But the truth is, and
despite all the math and calculations, plain and simply, I got lucky. I’m sure
there are many aircraft designers out there that go through the calculations and build
revision after revision only to be met with continued failure. (Just look at how crummy
many of your commercially-available kits fly...) I can now truly sympathize with them. It
took me about five times as long to design and build this model as opposed to simply
scratch-building one from a plan. So why do aircraft designers put themselves through this
emotional rollercoaster? Perhaps the award that I won at one of our club meeting sums it
up nicely... The award entitled "Dashing Undaunted Model Busters" was
unanimously bestowed upon myself when a model I was flying flew straight into the ground
under full power. I claimed; "It wasn’t my fault." Yeah... yeah... yeah...
they all said eagerly handing me the coveted certificate and plaque to proudly display for
a month. And after carefully reading the wording the certificate, I now know why aircraft
designers brutally punish themselves by undertaking such seemingly senseless pursuits. The
answer comes from a quote on the certificate of which I would like to quote a passage from
same... "There can be only one reason why any man would put himself through such
agony – DUMB, real DUMB." How appropriate and ironically, how true. So if you
think you are DUMB enough, go ahead and try to design a plane of your own. And if you are
really DUMB enough like me, it just might make you come back for more. I now have plans to
design and build a new pattern ship. If everything goes according to plan, it’s sure
not to fly!
Incidently, on June 1, 1999, the design of this aircraft was awarded a U.S. Patent No.
D-410,503. Go to my page on the U.S.
Patent Office Website and check it out!
***
~Andrew S. Rosz
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