Eric,

The pilot who removed his transponder antenna is a friend of mine, and I
talked with him about it at the time.

The glider is an ASW27, he was flying in competition with other pilots in
ASW27s who were well known to him as people and as pilots. Some were
members of his club.

He has a transponder fitted (Becker Mode A/C, not Mode S) because he
frequently flies high in wave, particularly in Scotland, where it is
necessary to talk to an air traffic controller and either a great help or
essential to have a transponder. He is also a professional airline pilot.

During the competition the transponder would not have been turned on. He
started with the antenna fitted because he did not realise the difference in
performance it caused. After two or three days, with his ship not going as
well compared with the others as he expected, he removed it. The
difference was immediate and obvious, he described to me the difference with
it fitted as turning the ASW27 into an ASW20! Remember, he had been flying
with the antenna for some time, it was only in contest against other similar
gliders with good pilots that he saw the difference.

Please do not talk as if flying in UK contests involves the same collision
risk with CAT as flying in the high skies around Minden (I have never done
that, alas!). I understand that there has not been an actual collision in
the UK between a glider and CAT or the military since 1947.

To anyone buying a new modern machine from Schleicher, Schempp or the
others, the cost of fitting a transponder is only a small percentage of the
total cost, but would still involve finding panel space, and sufficient
power (particularly if the transponder is to be on whenever airborne). But
there are still a lot of low value gliders in use in the UK, and a lot of
gliding being done where the actual collision risk where a transponder would
make a difference is very small. In the USA, I wonder how many of the 1-26
fleet are fitted?

W.J. (Bill) Dean (U.K.).
Remove "ic" to reply.


"Eric Greenwell" wrote in message
news:HQ4Kg.227$m36.105@trnddc02...


Derek Copeland wrote:
Jack,

I know that a UK pilot removed a transponder aerial
from his glider part way through a Nationals competition
because he was losing too much performance in relation
to his competitors in similar gliders. Also I fly a
Standard Cirrus, so I need all the performance I can
get!


You can't measure the performance loss that a transponder antenna on your
Std Cirrus, the drag is so little; nonetheless, the fiberglass fuselage
will let you mount one internally. The big advantage is it's protected
from ground and handling damage.

Change "netto" to "net" to email me directly

Eric Greenwell - Washington State, USA

www.motorglider.org - Download "A Guide to Self-launching Sailplane
Operation"