Imagine: Dick Johnson and "stupid" in the same sentence. That's not
unlike hearing Derek Piggot and "lousy instructor" in the same sentence.

Nice post, Bob.

Dan

On 2/3/2015 7:15 AM, Bob Whelan wrote:
On 2/3/2015 5:31 AM, Don Johnstone wrote:
At 23:52 02 February 2015, HGXC wrote:
On Monday, February 2, 2015 at 3:00:05 PM UTC-5, Don Johnstone wrote:
At 15:26 01 February 2015, wrote:

Some judicious snippage...

I own a Ventus and I have mine lubed at the annual, I have the openings
in
=
the wing like Dick Johnson suggested. If Schempp Hirth didn't want this
to
=
be lubed then they would have used a different bushing when they
made the
g=
lider. All gliders have short comings. The glider has been flown
over 30
ye=
ars and like all popular gliders over time, pilots find ways of
addressing
=
imperfections and every glider has some.

Dennis

Why is it that some glider pilots feel they know better that the
qualified
engineers and designers who design and build the machines they fly.
Maybe
using an unapproved lubricant on material that you do not know the
composition of, which might be damaged is unwise but drilling a hole
in the
structure to do it, that is stupidity of the highest order, such is
life I
suppose. I doubt that the "opening" made was properly sealed to
unsure that
moisture could not damage the GRP structure which is hygroscopic, my
advice. Do NOT purchase a glider owned by these people.
It is true pilots have a long history of finding incorrect ways of
addressing imperfections, proves the old maxim I suppose, if flying was
difficult engineers would do it.


Evidently, the original question touched upon "a topic of religion."
One church believes that gliders as-received from manufacturers cannot
possibly be improved by mere humanity unassociated with the original
design process (and to attempt improvement places one in the category
of the devil's spawn). The other church believes that use-/age-related
issues will inevitably appear, and might (if not should) be reasonably
addressed by subsequent owners. True - at least in the U.S. - for
sailplanes licensed with (see below) an Approved Type Certificate or
licensed Experimentally.

In my view, there's sound reasons for both views, and in an ideal
world, both can peacefully co-exist. Full disclosu I'm a(n
aerospace) degreed (U.S.-based) engineer, but one who's convinced
original designers were NOT (all apply): all-knowing; incompetent. In
other words, designers and the design team are humans like the rest of
us, though with (perhaps) some specialized training, and (definitely)
some specialized interests...again normal human conditions.

The U.S. is fortunate to have a healthy, vibrant, amateur-built
aircraft licensing category, from which - perhaps - some cogent
conclusions about this particular religious topic may be drawn. As I
type, approximately 20% of the U.S. power, single-engine, 4-or-less
seats general aviation fleet is licensed "Experimental Amateur Built"
(a presently increasing proportion), the rest having Approved Type
Certificates. Taken as a whole, the EAB category accident frequency is
(statistically and) significantly higher than the ATC category as
measured against fleet/licensing numbers. Unsurprisingly (in my view)
the percentages have a significant first-/early-flight bias (for
engine/fuel and loss of control reasons, mostly); thoughtful readers
can probably make accurate guesses why (an exercise and validation
beyond the point I'm trying to make with this post). Once beyond that
bubble, EAB and ATC accident rates are (arguably) identical. I expect
(but am not certain) accident *causes* are similar as well (when
comparing similar classes of pilots/flight, e.g. Visual Flight Rules
piloting).

My conclusions:
1) "Sound airplane design practices" are not limited solely to
factories and their design teams.
2) The weakest link is generally the nut at the top of the stick.

Stated another way, pretty much every form of human design
screwup/oversight possible in general aviation flying machines (e.g.
sailplanes) has been made long, long ago, and "best practices" are
pretty much available (and arguably well known) to anyone inclined to
learn from others' experiences. We're well beyond the "secret guild
stage" of aircraft structural design knowledge, and the "smoke and
mirrors" of ignorance-based myths.

That knowledge availability, along with the tendency of those geekily
inclined (most engineers, and many non-degreed people as well) is why
I'm OK with belonging to the Church of Future Improvement is Possible.

On the other hand, the World Wide Web has made it easier for everyone
(e.g. via YouTube) to easily see that Darwinism remains a potent human
genealogical force. Ignorance is potent, often more quickly than
knowledge. Hence I'd never try to convince members of the Church of
Don't Mess With Factory Stuff to change their beliefs.

Clint Eastwood was right: A man's got to know his limitations.

Further, who hasn't heard the truism: All generalizations are
false...including this one. In my view, there's at least one truism
that is NOT false: Perfection is never an option.

True in glider design, too. The trick is to know - or at lest to
remain within - one's limitations.

YMWV
Bob W.

P.S. I believe Dick Johnson was a degreed aeronautical engineer. His
entire working life was spent in the engineering field, and his
extracurricular soaring-and-sailplane-design-and-testing-related body
of work was prodigious. He likely passed on from heart failure in his
mid-eighties while flying the Ventus he owned for decades - the one in
which he drilled lube access holes. Make of all that what works for
yourself!

--
Dan Marotta