From the newsletter of the Silent Electric Flyers, San Diego
A Lesson in How to Crash
I recently destroyed a very nice
aerobatic 49-inch Yak. Not really a great thing to
do, but it happened and I hope by telling my story I
can save at least one other pilot from doing the
same.
I had just finished putting some very detailed
cockpit work in a very nice Cermark 49-inch Yak 54
so I could enter it in to the 2010 Spring Fling
Scale contest. I had earlier increased the power to
4S and had to beef up the motor mount with added
carbon fiber along the top and sides to hold the now
nearly 1,000 watts it could develop, so I was
confident it would perform very nicely.
In full-scale aviation, we always say it takes two
or three problems to make a crash, as we are trained
to recover from one problem at a time. I think this
story bears that axiom out. It took three distinct
errors on the pilot’s part to create an
unrecoverable situation.
It started with my desire to fly one afternoon after
I had just finished the above modifications and
checked the balance and control throws in my shop.
Because of all the things needing to be done, it got
later and later in the day before I got out to the
field. By the time I got settled in and ready for
takeoff the sun was very low on the horizon, but the
wind had calmed down a lot (error one).
I did my preflight and noticed that I had a little
extra throw in the surfaces, but that’s okay, I
wanted to be sure I could recover from any attitude
I got into during the trim flight (error two).
I took off and climbed out to the west, noticing I
needed to adjust the elevator a little for smooth,
level flight. While doing this, I let the airplane
get a long ways downwind to the east (error three).
As I started to turn toward me to come back to the
center of the field, I over rotated due to the
larger-than-needed throws of the ailerons, and due
to the low sun angle I lost orientation of how far
I’d banked and in my attempt to recover I must have
thought I was inverted and zigged when I should have
zagged.
End result was a near full-power dive into the
ground instead of pulling up smartly.
So how could I have avoided this unnecessary loss of
a very nice and near new airplane?
1. Don’t get in a hurry to go do a flight. If it’s
3:30 p.m. when you leave for the field in the
winter, it will be dark in only 1.5-2 hours.
2. A headwind is a good thing, dead calm requires
more roll out and longer takeoffs.
3. Larger surface throws are inherently bad for
control. Use small, reasonable throws and check that
the surfaces are in line with the wing or tail fixed
surface for easier flight control.
4. Keep your situational awareness! Don’t let one
aspect of flying (ex. trimming) get in the way of
overall flight path control. If you get too far away
with an “active” model, you’ll have more problems
keeping it under control.
Q
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