| Re:-.1
> You mentioned in a note that contest directors should do something
> about taxiing aircraft and I would assure taking off and landing
> to reduce the problem of one transmitter overpowering another
> transmitter.If I understand the problem correctly any transmitter
> can overpower another transmitter no matter what frequency they
> are on.
Yes Tom absolutely correct. Drive past a broadcast band TX in your car and it
break's through your car radio I/F stage no matter what station you are tuned
to.
It scares me every time I see a Pilot(?) walk to the end of a runway with a
model, square himself with the model and the runway, then commence to take off
in the direction of the other pilots standing in the defined pilot area.
In out club we permit this practice with new fliers for a short time, they are
then required to stand in the designated pilot area for all take off's.
I have seen one club actually put Cyclone Mesh (about 2' high) around the pilot
area to prevent models hitting the other pilots due to ground loops.
I don't have an answer to the problem, awareness of the problem by all
concerned and a willingness to work around the problem is the best compromise I
know.
John.
|
| Tom,
In response to your question, I can't say that I have [or know of] the defini-
tive solution to prevent 3rd IM and swamping ("capture") type incidents but here
is how the flight lines are set up on the 4-improved, club-hosted, public flying
sites here in the Phoenix area.
First, it was decided that five flight lines (pilot stations) was the optimum
arrangement [as recommended by George Meyers in the "Radio Techniques" column of
Model Aviation). No more than five aircraft are ever permitted in the air at a
given time. Any more than five begins to constitute a collision/safety hazard
anyway so this conclusion was rather painless to arrive at and agree upon.
Frequencies were then sorted [again, per recommendations by George Meyers) and
assigned to each flight station in such a manner that, where a 3rd IM potential
exists, at least two of the involved frequencies were assigned to the same sta-
tion, thereby eliminating the possibility of ever having all three frequencies
in use at once. Hence, a pilot's particular frequency [say ch.-44] can only be
flown from it's assigned flight station [say station-1] and no other, even
though channel-44 may be open/available. To fly it from "any" another [vacant]
station defeats the system and opens the possibility for a 3rd IM shoot-down.
Flight stations are separated by 15-feet to minimize/eliminate cross-talk prob-
lems between transmitters. This makes the overall length of the flight-station
area 45-feet from station-1 to station-5. The one potential problem which this
setup does nothing to address is the "capture syndrome" when taxying under an-
other transmitter. I don't know exactly what can be done to alleviate this ex-
cept to make all pilots aware of the potential and put the onus on them, indi-
vidually, to avoid potential capture situations. In other words, DON"T taxi
under someone else's transmitter!
Locally, we educate all field users to the danger and instruct them in recogniz-
ing risk situations, encouraging them to avoid taxying under another's extended
antenna at all costs. For the pilot furthest upwind, this means taxying out on-
to the runway at a bias away from the flight-station area so as to avoid taxying
under as many as 4-transmitters. The taxying pilot has the responsibility "not"
to taxi into the path of another aircraft taking off or landing and, to ensure
that this does not happen, all pilots are required to have a spotter standing
with them at all times to spot and call traffic and to loudly announce his pi-
lot's intention to taxi out, takeoff, land, etc. Naturally, dead-sticks have
priority in any situation but the pilot [or his spotter] is expected to make
other pilots aware of the emergency by loudly announcing the problem.
Other safety/common sense/common courtesy rules necessary to making the system
work are as follows:
1. A pilot must have his appropriate frequency-pin "AND" his assigned
flight-station must be open before he can fly. Absolutely NO flight-
line swapping is permitted! (This to preserve the integrity of the
3rd IM prevention measures.)
2. Pilots are required to taxi, takeoff, fly, land and taxi back while
standing in the appropriate flight-station. Pilots are NOT allowed to
stand behind their aircraft [on the runway] while taking off.
3. All takeoffs and landings are in line with, NEVER across the runway.
Traffic pattern is determined by the prevailing wind.
4. All turnouts "MUST" be "away" from the flight-line/pit area. Flying
behind the flight-line is not permitted at any time, for any reason.
5. No one is allowed on the runway for any reason except to retrieve a
stalled aircraft or remove debris which may have fallen off an aircraft
and then, ONLY after loudly announcing, "Man on the runway" and confir-
ming that all pilots have heard and acknowledged the announcement.
6. Aircraft are only started on the flight line adjacent to the appro-
priate flight station. No aircraft are ever allowed to be started or
run in the pit area. An area, well removed from the pit area, is set
aside for engine test/test-running purposes.
7. Spectators or others not directly involved in the operation of one of
the maximum of five aircraft allowed to fly at any given time are not
allowed on the flight line and must stay behind a deadline 75' from the
runway centerline.
If this setup seems harsh or severe, allow me to assure you that "IT WORKS!"
The pain level to implement is slight and insignificant with regard to the safe-
ty benefits , not to mention the peace of mind enjoyed with the knowledge that
the possibility of a 3rd IM shoot-down has been eliminated. It "does," however,
require the understanding and cooperation of **"EVERYONE"** who uses the field!!
Just one inconsiderate person abusing the rules can sabotage all the security
offered by the system. For that reason, all pilots are encouraged to self-police
the system for the benefit/safety of all.
Adios, Al
|
| Re: .-2, Anker,
As Tom alludes to in .-1, resistance to change is always the biggest
obstacle to progress, even when the benefits are obvious. Tom may
also have hit on the specific reason for resistance: the fact that
pilots can no longer stand behinf their aircraft on takeoff.
This seems to be more an eastern phenomena. We learn to takeoff/land
standing remote from the aircraft from day-1 out here but a big
flap developed at one of the first U.S. Scale Masters when some eastern
based pilots, with Ramon Torres in the vanguard, insisted that they
be allowed to go out on the runway to stand behind their aircraft
on takeoff. Safety considerations shut this proposal down immediately
and Torres carped and griped throughout the meet that this gave
an unfair advantage to the western pilots. HOGWASH!!
In any event, taking off/landing while standing remote from the
model is simply an acquired skill..., the throwing down of yet another
"crutch" and I can't imagine why any modeler would _not_ want to
improve their pilot skills; maybe that's a way to sell the idea.
The benefits are too obvious to be ignored; reduced or eliminated
3IM, better safety, etc., etc. Are the objectors satisfied with
being [Ugh!] toy-drivers or wouldn't they prefer to become accom-
plished pilots?
Tom reminded me that, in addition to the 30' spacing between pilot-
boxes (all our fields have 5), we allow no more than 5 ships in
the air at a time. This is accomplished by having 5 flightline
clips; to fly you must have the appropriate frequency clip _AND_
a flightline clip...if all 5 flightline clips are out, you retain
yer' frequency clip and wait for the next available flightline clip.
This cuts down a lot of confusion, not to mention traffic, and ensures
that each pilot has a properly separated box to stand in.
A fellow from one of the local fields told me at our recent fly-in
that 3IM used to run rampant at their field, there being 2-3 instances
of it weekly. Now, he told me, after instituting the separated
pilots' boxes and the 5-at-a-time rule they observed us using, they
can't remember the last time they had a case of 3IM. Pretty good
testimonial, I'd say...especially when you consider that they have
_NOT_ instituted any sort of frequency-to-flightline sorting...just
the separation and the 5-plane limit.
We take no credit for the system...it was all taken from this-or-that
article by the radio experts, e.g. Odino, Meyers, et al, published
in the national R/C mags.
:
| | 00 Adios, Al
|_|_| ( >o
| Z__(O_\_ (The Desert Rat)
|