Hear Ye!

March, 2003
No. 429

FROM THE PREZ
by Bob Sudermann

For those of you who didn't make it to the banquet, you missed a great time.
My thanks to the organizers, Carl Sutton and Al Campana. Also thanks to Bob
Dolan who was exquisite as the Master of Ceremonies. Bob added a few awards
of his own and, without going into detail, he took a shot at just about
everyone.

To the awards: The Doug Davidson Award went to our treasurer, Carl Sutton,
for his commitment to support and help guide the Valley Forge Signal
Seekers. Carl has performed an outstanding job as treasurer. He is one of
our Flight Instructors and is always available to assist anyone who needs
help or has questions. Thanks for your time and effort, Carl!

This year, the Technical Achievement Award went to both of the nominees,
Mike Myers and Russ O'Brien. As you know, Mike has been pushing the envelope
with his Autogyros, and Russ continues to amaze us all with his homemade
mechanical marvels. Neither one of these guys will sit back and let someone
else figure out how to do something. They see a problem (challenge) and
figure out a way to overcome it, and we all benefit from their efforts.

Joe
Yalove was presented the award for "Best ARF Destruction" for his efforts
with his Hanger 9 Taylor Craft. We all know that some of us have a definite
opinion about ARF's. Some think they should be banned, while others think
they are the greatest things since sliced bread. I don't like to see anyone
crash an airplane, but it happens. When it happens to an ARF, I don't feel
nearly as bad, and I have been known to make a few discouraging comments
about ARF's - especially when an accomplished builder shows up with one. On
this note, one of our members has performed a great service - he destroyed
his ARF. Congratulations, Joe.

Special awards were presented to Warren Barrick for his efforts as club
president and to Dee Messina for his efforts as club secretary. I believe
one of the highest compliments for anyone is to be labeled an "Ambassador"
for aircraft modeling. Both Warren and Dee fall into this category because
they portray the best of our hobby both within the club and outside. They
give back more than they get and thoroughly enjoy the process. Thanks again
for your efforts, and don't be surprised if you get tagged to help again in
the near future.

Please plan to attend the March meeting. Long time club member Joe Krush is
the guest speaker. As some of you remember, we used to have an annual Indoor
Fun Fly (which we should try to revive), and Joe is our resident expert on
indoor aircraft.

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VFSS INSTRUCTORS' MEETING
by Steve Kolet, Club Secretary

February 4, 2003
Approximately 20 members were present.
Meeting was opened at 7:05 PM by President Bob Sudermann.
The purpose of the meeting was to review the VFSS Student Instruction and
Checkout Worksheet.

Item 1: All new student members of VFSS are to be given a worksheet and
student member card when they join. It is the new member's responsibility
to carry the worksheet so that the progress section can be filled out to
monitor progress. The student guide is intended to help new students learn
to fly safely in an efficient program. The worksheet was reviewed and minor
errors were noted, and pen and ink corrections were made to copies at the
meeting. The files were corrected for the next printing.

Item 2: The worksheet has an outline of recommended minimum items to be
discussed, reviewed, and completed in the training sequence. It is
imperative that all instructors follow the training outline, complete the
flight log, and initial the qualification worksheet as events are
successfully completed. Upon completion of all items on the qualification
worksheet, the student and primary instructor will sign the qualification
sheet. Bob Sudermann or Tom Burns will be notified and will complete the
final checkout. The student will be given a VFSS membership card at that
time and will be certified to fly that type of aircraft solo.

Item 3: The new member is required to complete the VFSS Qualified Pilot
Status sheet as he/she progresses with other types of aircraft.

Item 4: There was discussion about instructor availability for evening,
daytime, and weekend.

Item 5: Instructor/student assignments from fall were reviewed, and several
new students were assigned.

Meeting ended at approximately 8:30 PM.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

CLUB CALENDAR

Tuesday, March 4th -
BOG meeting at the church, 7:00 PM, room 207. Schedule Fun Fly Events and
general meeting topics.

Tuesday, March 11th -
General Membership meeting at the church at 8:00 PM. Guest speaker will be
Joe Krush. Joe will be discussing the 'Indoor' aspect of our hobby.

Tuesday, April 8th --
BOG Meeting at the church, 7:00 PM, room 207.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

BATTERY READY FOR SPRING?
Submitted by Al Campana

Although we are still in the depths of winter with a good coating of snow on
the ground, spring is just around the corner. Baseball teams are in their
warmer climates preparing for the coming season, and most of us can't wait
to get back on the flight line to once again enjoy flying our models.

With this in mind, it is a good idea to begin checking our models and
equipment for normal wear and tear, ageing, and reliability. For example, if
you have been flying for several years, you know how easy it is to forget
how old your batteries are in your transmitter and receiver.

But that's another story. This time we'll focus on the old reliable 12-volt
gel cell used to control your starter, fuel pump and glow igniter. I
recently came across an excellent article written by "Red" Scholefield, a
well known battery engineer, in which he provides some interesting facts
concerning these batteries. It is reprinted here for your information

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

CARE AND FEEDING OF YOUR SEALED LEAD ACID BATTERY
by "Red" Scholefield

Lead Acid (Gel Cell) Charging

Lead acid (gel cells) should be charged with a constant potential charger
specifically designed for these batteries. These are sometimes referred to
as a CVC charger. You can charge them with a constant current charger, but
you must terminate the charge when the voltage reaches 14.7 volts. You
should not exceed the C/10 charge rate. If you have a 7 Ah battery in your
field box, the maximum constant current charge rate should not exceed 700mA.
It will take about 14 hours to charge from a fully discharged state (voltage
less than 12 volts.). A CVC (Constant Voltage Charger) is exactly what the
name implies. It is clamped at a certain voltage and puts out all the
current it can until the battery reaches the clamp voltage, usually
something around 14.5 volts, then the current drops off to maintain it at
this voltage. A constant voltage charger is characterized as one having a
current capability of supplying a fixed voltage to whatever load is applied.
A constant current charge on the other hand will provide whatever voltage is
necessary to force a fixed value of current through a load. Constant
current charges have a much higher internal resistance than the load so that
any variation on the load will not change the current being supplied.
Constant voltage charges have a very low resistance as compared to the load
and will supply whatever current necessary to maintain a given voltage at
the load.

Many inexpensive chargers used for sealed lead batteries are what are called
taper chargers; these are set up so the voltage tapers off as the full
charge voltage is reached. True constant potential (CVC) chargers can be
quite expensive so a compromise is made in the design to control costs.

We have used the term sealed lead battery in this discussion. These
batteries are not truly sealed as cylindrical Ni-Cds are. They have a
gelled electrolyte system where there is a modest recombination of the
oxygen in overcharge in some designs. All require venting of the oxygen and
hydrogen byproducts of charging and discharging. This is why you should
never totally seal these in a field box where these gasses can accumulate.
Mixtures of oxygen and hydrogen can cause spectacular "events" if a spark is
provided (from an electric fuel pump motor).

How much charge is there in the battery? Unlike Ni-Cds, you can read the
remaining capacity quite easily with a voltmeter. After the battery has
been on rest for a few hours, read the voltage (no load). A reading of 12.0
volts is essentially fully discharged while 13.0 is fully charged. This is
a fairly linear relationship so a reading of 12.4 volts means you have 40%
of the capacity remaining.

Never leave a lead acid battery in the discharged condition or sulfation
will result. The sulfuric acid in the electrolyte reacts with the sponge
lead active material and forms lead sulfate. It is a poor conductor. This,
coupled with the H20 left after you take all the S out of H2S04, is also a
poor conductor, so trying to charge requires a lot of voltage to push the
current through to convert the active material back to the charged state.
Sometimes they just cannot be brought back from the sulfated state.

The good news is that sealed lead batteries retain their charge much longer
than Ni-Cd; at room temperature it's well over a year. So all you have to
do is make an occasional open voltage check to see if you need to charge it.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

HOW TO REDUCE RC ENGINE NOISE
by Ron Scott

Here are some things I've learned over the years that may help you reduce
noise levels.

Use a good muffler system. The original muffler should provide a good level
of sound dampening-if the baffles haven't been removed. There are several
after market mufflers available in various model magazines.

Add a rubber exhaust deflector. This can reduce noise from 1-3 dB in certain
cases. It also extends the exhaust gas residue out a few inches from the
airplane.

Use a larger prop. Increasing the prop diameter by ? inch to one inch can
have a 2-5 dB reduction in noise. Basically this slows down the engine rpm.

[Tech. Ed. note: Important! If you have a damaged prop, it should be used
for paint stirring. Only if there are very minor dings or surface flaws on a
prop should the following suggestion be done. Clean and smooth; do not
remove material.]

Clean and smooth prop. Clean edges will cut the air smoothly with less
noise, whereas cuts and dings on the edges can cause friction and drag in
the airstream-thus causing noise. I use 150 grit sandpaper for the rough
areas, then 400 grit for finishing work. When you consider that a 10 inch
prop at 10,000 rpm is traveling at 297 mph the aerodynamic profile of the
prop makes a difference. A cut in the outer edge can cause a hissing sound
and add to the engine noise.

Lower the fuel's nitro level. For every 5% increase in nitro, expect a 1 dB
increase in noise level. Reducing the nitro in the fuel from 15% to 5% can
reduce the noise by 2 dB.

Keep the airframe tight. Often times, noises develop in the fuselage and/or
wing areas due to mechanical resonances due to engine vibrations. This is
often caused by loose hardware, wing braces, etc. Make sure all hardware is
secure and tight (no loose wing ribs, etc.). Soft engine mounts can reduce
or eliminate these noises by de-coupling the engine from the fire wall. This
essentially lowers the resonant frequency and partially damps the high
frequency vibration.

De-tune (richen) the engine's fuel mixture to reduce rpm. This obviously
reduces power, but the engine is quieter.

Go from a two-stoke engine to a four-stroke engine. The four-stroke engines
are usually quieter. The added benefits are worth the additional money. A
four-stroke engine is quieter, more fuel efficient, more reliable, and idles
more smoothly. It also leaves a lot less oil residue all over the airplane.

from Update
Santa Barbara Radio Control Modelers
Peter Nickel, editor
Santa Barbara CA

Feedback or comments to: Marilyn Ayres , HearYe editor
Michael Myers, Webmaster

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