I've been watching Dick Johnson's reports for several decades. The usual
pattern is for a new glider to be produced with a claimed L/D that is
significantly higher than what results from Dick's testing. The
manufacturer will sometimes pick on dick's methodology and claim that it
doesn't show everything about the glider in question or is somehow unfair.

Much later, when the glider is no longer in production, the general opinion
will be that Dick was dead on with the original report.

Dick's methodology is the best there is given limited budgets. Even so, the
results are far better than what could be reasonably expected which is a
tribute to Dick's skill as an engineer and pilot. A great benefit is that
the same methodology has been consistently and meticulously applied to a
huge number of gliders over a very long time so there is a lot of data to
compare and consequently a lot of confidence in the results.

We all owe a great debt to Dick and the TSA for the years of work they have
done testing gliders.

Bill Daniels


"John Galloway" wrote in message
...
At 10:30 02 May 2005, Chris Rowland wrote:
On 28 Apr 2005 20:19:15 GMT, John Galloway
wrote:

Well - there's a thing -as a non SSA UK pilot for years
until yesterday I could get straight to the Johnson
flight tests (including yesterday the newly posted
ones) and then today all of a sudden I can't.

http://www.ssa.org/Magazines/Johnson.asp

Anyone got a new link?

The wayback machine web site has som of them -
http://web.archive.org/web/200402141....ssa.org/Magaz
ines/Johnson.asp

Chris

Chris,

Thanks. That's a good archive site that I knew nothing
about - and it gets me back to what I could previously
access.

I still feel that it is a shame that the SSA have decided
to deny general web access to all of the Johnson tests
at the time they have posted some more recent ones.
The are a unique resource of independent data.

No polars are ever going to be totally true but Dick
Johnson has a record of picking up quite few valid
performance issues over the years. DFVLR polars are
surprisingly smooth, surprisingly better at higher
speeds than Johnson's, don't show individual flap polars,
and are available only by individual purchase 2 years
after measurement or in manufacturers manuals. I always
use Dick Johnson's data (if available) for glide computers.

John Galloway