Glider Stealth
Shawn Curry
Over the three years or so I've been following this newsgroup I've read
lots about visibility of gliders to other aircraft, transponders and
ATC, but I can't recall a discussion about how a glider appears on
radar, either ATC or airborne.
Anyone know?
I would suspect a 2-32 or Blanik makes a nice target. What about glass?
Carbon fiber? Wood?
I've bicycled a lot over the years-always assuming I was invisible to
cars (trust me, its true). Is the same true for gliders on radar?
Cheers,
Shawn
David C. Rolley
You need to fly your Ventus down to Kelly and let us see it... :)
About the ATC radar question, assume you are invisible.
It may be different around the country, but for the most part the ATC
system does not use the primary radar return reflected from the
aircraft. The ATC system is setup for transponders. Even if you have a
transponder you might be invisible. Years ago a commercial commuter
flight and a jump plane collided near the northern Colorado front
range. Turns out that the jump plane was not cleared to be where it
was, however, it had an operating transponder set to a code beginning
with 12xx. Unfortunately ATC was blanking the display of aircraft
returns using codes starting with 12xx in that area. ATC also has
software that blanks the display of very slow movers. I've seen
articles that indicate targets with ground speeds below something like
60 knots drop off the display.
It seems that for us (glider types) to be visible to ATC radar (and to
the controllers working the positions) we need a transponder AND we need
for the local ATC folks to be aware of us so they can configure their
equipment to deal with the challenges associated with our flight profile
AND they need to have a reasonable enough work load that the additional
information displayed can be effectively used. Supposedly some areas
have those conditions (Las Vegas and Reno?).
The right kind of transponder in our gliders might help the big boys
that have the transponder based collision avoidance systems.
Dave Rolley
Christian Hostettler
civil aviation he cannot see gliders, but that he can quite easily,
when he is doing the same work during his military repetition
courses. Looks like the military radar units are much more
sensible.
SwissChris
"Shawn Curry" <sc...@earthlink.net> schrieb im Newsbeitrag
news:3A686024...@earthlink.net...
Dicksortie
their radar to ignor flying objects flying less than 50 MPH or 50 Knots
(probably 50 Knots). I often wonder if I appear and disappear from their screen
as I dive and climb and if this gets their attention.
Dick
Al
telling incoming heavies your location.
So I dont think they turn down there scopes to squelch out sailplanes and
large birds '-)
Al
"Shawn Curry" <sc...@earthlink.net> wrote in message
news:3A686024...@earthlink.net...
OscarCVox
They can see gliders quite clearly but sometimes have problems when we are
thermalling as it apears as a mass of returns. Also at longer ranges a number
of glider returns will blend into each other as we tend to fly a lot closer to
each other than GA aircraft.
They had a particular problem last year when we had our comps. 130 odd gliders
made a long lozenge on their screens streching 30 miles to the north. Military
aircraft were told to fly low or high to avoid us. Amazing the Mk1 eyball is
still superior under certain conditions :-)
Dan Marotta
I'm in San Antonio these days... I once contacted Denver Approach to
report my position for traffic avoidance. I was at 17,500 MSL and about
15 miles SW of Centennial airport. After giving my GPS position they
were able to pick me up. They also seemed to take great pleasure in
pointing the glider out to the other traffic. The jet drivers were
amazed that a glider could be there and making 155 Knots ground speed.
BTIZ
McCarran Airport, Las Vegas NV. We do not have the transponder code
agreement that the pilots around Minden NV use for the Reno area, I believe
there they use 0440 for gliders. I don't think anyone other than some
visiting gliders have transponders at our local airport, Jean NV.
Our local ATC Appch control for the Class B can see glass ships, as well as
others. They know when we are flying, and watch for us. I have been flying
Grob 103, Grob 104, Libelle 201 and also Blanik L-13 (metal) and Schwizer
2-33 and 1-26. We tune up appch and listen in to get cues for the heavies
descending into McCarran and they have accurately called us as traffic and
"possible glider", They have also picked up the LS-4, and ASW-17 (wood
spar?) as well as others.
As former ATC myself, on older radar systems, it depends on how the radar
operator sets up and "tunes" his presentation. During migratory season, I
have tracked Ducks flying in their V formation, confirmed by passing
aircraft, with the long range ARTCC radar. ( the ducks bellies were full of
radar reflecting water)
The "blanking Ground Speed" setting referred to in other messages has been
primarily used to blank out ground clutter, or highway trucks in some areas.
Also older radars were susceptible to a normal "blind speed" on picking up
slow movers traveling perpendicular to the radar beam, you were not moving
fast enough (azimuth change relative to the radar) to be identified and
displayed as a "target" and not "clutter" that was filtered out.
Tactical pilots would refer to that as "Beaming the Threat"
Hope this helps,
TZ
"Shawn Curry" <sc...@earthlink.net> wrote in message
news:3A686024...@earthlink.net...
F.L. Whiteley
Watton radar would doppler us out at 50 knots or so (mostly to avoid geese I
gather). So gliders would vanish in thermals and reappear in cruise. The
doppler was adjustable and if they knew of a contest, they'd keep a closer
eye on things.
Off topic, but I was crossing the end of the runway at RAF Mildenhall at
night, having a green light. At the center of the runway, the undercarriage
of a C-130 appeared, much too close, through my sunroof, and as I looked up
in amazement the landing lights switched on. It arrived, unannounced,
having evaded Watton Radar (and several radio towers) all the way. It was
neither a US nor UK Herc and was immediately surrounded by twenty trucks
with flashing lights and about 40 troops with M-16's.
Frank Whiteley
Dan Marotta
Dan Marotta
LS-6a, "4"
Ian Johnston
: Over the three years or so I've been following this newsgroup I've read
: lots about visibility of gliders to other aircraft, transponders and
: ATC, but I can't recall a discussion about how a glider appears on
: radar, either ATC or airborne.
: Anyone know?
We had a military ATC chappie at a club I fly from and where conflicts
between fast jest and gliders are distressingly common (all at 300' AGL
in the hills...) he said they could generally see us fine, but that a
radar reflector would help enormously. I intend to fit a marine 1'
aluminium corner cube inside my fuselage before I next fly there...
Ian
Robert Storck
wrote:
>Shawn Curry <sc...@earthlink.net> wrote:
>
>: I can't recall a discussion about how a glider appears on
>: radar, either ATC or airborne.
Check out Phil Wills' books. One of them detailed how he was flying a
Minimoa out into the English Channel to check early pre-WWII radar.
They had even replaced the cables and metal control rods in this all
wood sailplane, and were relieved even that crude radar could pick it
up. Obviously, they were worried about invasion gliders.
My first experience was flying the cliff at Torrey Pines in '58 with
an low overcast but strong enough wind to maintain about 800' above
the cliff. Suddenly there was a real loud noise and the smoke trails
of a couple F3H Demons that had bracketed me on their way out to sea.
A Navy pilot in our club, Lacey Collier told me that they had not seen
the green and white Schweizer 2-8 until just before they had passed
me. They had been warned about flying over the Del Mar race track to
the north and La Jolla to the south, so expected their fire control
radar to pick up other traffic. That strengthened my faith in our 'all
weather' fighters.
Since then I have flown all wood sailplanes to serious altitudes, but
have always included a reflector from life rafts inside. I grabbed a
bunch when I was in the Navy.
Avoiding radar was part of my mission while in the Navy, and several
times I managed to get an F-4 all the way to Front Royal, VA without
being painted. Of course, we were spoofing enemy radar, from the evil
Air Force.
Ian Strachan
<bst...@sprynet.com> writes
>On 20 Jan 2001 16:49:09 GMT, Ian Johnston <engs...@sable.ox.ac.uk>
>wrote:
>
>>Shawn Curry <sc...@earthlink.net> wrote:
>>
>>: I can't recall a discussion about how a glider appears on
>>: radar, either ATC or airborne.
>
>Check out Phil Wills' books. One of them detailed how he was flying a
>Minimoa out into the English Channel to check early pre-WWII radar.
>They had even replaced the cables and metal control rods in this all
>wood sailplane, and were relieved even that crude radar could pick it
>up. Obviously, they were worried about invasion gliders.
It was actually an early experiment in reducing radar cross section and
a wood glider was a useful trials vehicle. I flew this glider in the
early 1060s, a Kite 1 not a Minimoa from what I remember. When you did
the DI you could see the wooden dowels in the wing instead of metal
cables and rods.
--
Ian Strachan
Nolaminar
RE Gaines
Ian Strachan
<I...@ukiws.demon.co.uk> writes
snip
>I flew this glider in the
>early 1060s, a Kite 1 not a Minimoa from what I remember.
I have already had my leg pulled about my age ! I may be old but not
that old. A late night typo for 1960s. Mind you, I was impressed when
someone from Arizona asked me about the 1066 Battle of Hastings .....
Anyway, I looked up the flight in an old logbook and it was in a Kite 1
on 18 August 1962 from Tebay, the site of the Lakes Gliding Club in
those days. I had previously seen the glider at Lasham before that,
with its wooden square-section dowels as control push-rods.
Philip Wills' book "On Being a Bird" describes what they did (pages
22-29). In 1940 some experiments what we now call Radar Cross Section
(RCS) were done by flying various aircraft in range of the RDF (Radio
Direction Finding, primitive radar) station at Worth Matravers, SW of
Bournemouth. As gliders were believed to have the lowest RCS and big
ones could be used a troop transports, a selection of sailplanes were
requisitioned and flown by various glider pilots including Philip Wills.
They were towed South over the sea by Avro 504 biplanes and released,
according to Philip, at some 10,000 ft. The 504 then cleared and the
glider flew back to the coast and landed back in a field near the RDF
station, being tracked by the RDF and its radar return measured. Philip
mentions glider types such as the Minimoa and Viking, but the Kite 1 is
of the right vintage and I see no other reason for fitting special
wooden dowel control rods other than for radar experiments.
Philip recalls one flight where he sank below the level of the local
chalk cliffs, but ridge-soared up again while the radar people were
looking for the wreckage on the beach below ...
A lovely man, Philip, and very kind to me when I was a young sprog on
BGA committees. He was always keen on free distance flying and what he
would have thought of what we do now would be interesting to hear, from
his position in "the great thermal in the sky", where I guess we will
all (metaphorically) join him some time ....
--
Ian Strachan
Birger Bulukin
Ian Strachan <I...@ukiws.demon.co.uk> wrote in article
<oIlGrZAY...@ukiws.demon.co.uk>...
Believe his sons Justin and Chris could elaborate on this!
--
Birger W. Bulukin