Hear Ye!

The Official Newsletter of the :
Valley Forge Signal Seekers
Radio Controlled Model Airplane Club

An AMA Gold Leader Club

January, 2003
No. 427

Bob Sudermann Elected President for 2003

Alex Primas, Vice President
Dee Messina, Secretary
Carl Sutton, Treasurer

FROM THE PREZ
by Bob Sudermann

Happy New Year!

I hope everyone had a great Holiday Season and is diligently working on a
new project for the upcoming flying season. I need to start by thanking all
those who supported and guided the club in 2002 for their hard work.
Specifically I would like to thank Dee Messina for 6 years as Club
Secretary. This tends to be a job no one wants to take on, and Dee has done
a great job (we are still looking for someone for 2003). Also thanks to
Warren Barrick who has been a stabilizing and calming force as he has guided
the club as president for the past 4 years. I hope those of us taking over
can continue the good work of Warren, Dee and the rest of the outgoing BOG
members. Thanks again to all.

If you missed the December meeting, you missed an amazing display of
artwork. Thanks to Robert Engman for sharing his passion. Most modelers
have a knack for envisioning an aircraft or mechanical part in our mind's
eye and transferring that vision into a flying model. Bob's visions and his
ability to convert them into tangible objects is totally amazing.

Just a quick history for those who do not know me. I have been involved in
RC and the Valley Forge Signal Seekers since 1987. I was president in 1993,
1994 and again in 1998 but had to resign due to job conflicts (2.5 years on
a project in Puerto Rico). I tend to build larger airplanes because 'They
Do Fly Better' and am currently working on a 101" AT-6 Texan. I look
forward to this year's challenges and achievements and working with the new
officers and BOG.

I can't wait for the flying season to start - see you at the field.

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

DESIGNING AND LASER CUTTING MODEL AIRPLANES
by Robert J Caso and William Doucet

A number of people have asked me about the process followed in cutting RC
airplane parts on a laser, so here goes. A laser cutter is nothing more
than a glorified 2D plotter having a moveable arm that moves along a "Y"
axis with a lens mounted thereto that moves along an "X" axis. The light
reaches the lens by way of precisely mounted 45-degree mirrors that direct
the laser beam emanating from a laser fixed at the back of the machine. A
small blower cools the laser itself and a larger external blower used to
extract fumes is hooked up to the laser with flexible pipe and is vented to
outside air. Software-driven servomotors driving rubber belts provide the
required movement of the arm and lens head, and the 12" x 24" stainless
steel cutting table automatically adjusts up and down ("Z" axis) to provide
the correct focal length for the laser beam. Printer drivers loaded into a
PC drives the laser - just like any printer - and just about any software
that has that feature can perform "printing." Most of the wood we commonly
use in RC aircraft construction can be accurately cut - up to about 1/4" for
balsa and 1/8" for plywood. The wood itself is temporarily affixed to the
cutting table using tape to prevent movement during the machining operation.
Our laser is rated at 30 watts, although a number of ratings are available,
and it runs on normal 115-volt household current. Some of the
higher-powered lasers require 220 volts and water-cooling.

So how do we make the parts for a model? There are basically two ways. The
first is starting with an already drawn paper plan, the parts printed
thereon being scanned using a tabletop scanner. Once all the required parts
are scanned, they must be imported into a CAD package (we use ModelCAD) and
traced by hand, since the resulting outlines of the scanned bit-mapped image
are usually ragged and imprecise. This is a labor-intensive process. A
bit-mapped image is basically a series of small black blocks forming the
outline of an object. CAD packages produce vector lines which are much more
precise. Therefore, an added issue is one of obtaining a precise part durin
g the tracing process - where do you draw your line against a bit-mapped
image? This is especially an issue where parts contain a slot, such as in
the case of a spar slot in a rib. If you're off a couple of thousandths
either way, the parts won't fit well. To deal with this, we have created in
CAD a separate file of pre-toleranced slots such as 1/8" x 3/16 that we
import and lay into the drawing. While this saves time, there still is the
issue of exactly where along the rib that the slot lays. Only by making
some test cuts in poster board or by redrawing the entire wing plan form and
comparing it against the ribs will give you this answer.

The second way to make a model is to start from scratch right in CAD. If
you're doing something that's scale, a good way to start is to get a three
view, scan it in and import to CAD. This will give you the overall outline
of the aircraft and then you can start drawing its infrastructure. This is
where it pays to have built a few model airplanes. Sometimes we cheat and
look at plans for a similar airplane to get some ideas. Before you start
drawing away, however, you first have to scale the model - how big do you
want it? CAD doesn't care - it works in units: millimeters, inches or
miles. The infrastructure for an 80" Fieseler Storch would differ greatly
from a 30" inch model in terms of wood sizes, rib and bulkhead spacing,
materials and the complexity of the parts. How accurate do you want the
model to be? Gas or electric? Flaps or not? All these questions play a
part in the basic design. Referencing proven designs helps immensely in
solving these model-engineering problems.

OK, so you have the three view of the model scanned and scaled, now what?
Start at the beginning - for the fuselage side view, put a line in for the
thrust line of the model and draw lines corresponding to its outline.
Determine your bulkhead spacing and draw vertical lines up and down through
the thrust line to the outlines. Do the same for the top view. The lines
in the side view corresponding with those in the top view represent a 2D
general boundary outline of bulkhead. Put them together and you have the
front view of a rectangular bulkhead. Now any curves are lofted in, and
slots and lightening holes are added. There's a bulkhead. I am
oversimplifying a bit here but this is the general procedure. For the wing,
import a rib profile (many CAD programs have them) - perhaps a Clark Y.
Draw the outlines of the wing and put in centerlines for the spars and ribs.
Take your rib profile and lay it against one of the rib centerlines. If the
rib is too big or small, adjust it by squeezing or stretching it with the
appropriate CAD function. Import an appropriate slot from your library and
place a few on your rib where it intersects any of the spar centerlines.
Cut off the front and back of the rib to allow for leading and trailing edge
structure. At this point, the rib is a series of separate drawings so the
thing to do is to retrace the rib along its curves and around its slots so
you have a single entity. If you're working with a constant chord wing, you
're pretty much done.

OK, so you have all these parts drawn and want to cut them. Let's say some
are to be cut from 1/16" balsa and some from 1/8" balsa. Create a "cut"
file in CAD by cutting a pasting your parts in to a separate file. What
sizes does balsa come in? Well, the thicknesses here are no problem, but
should we use 3"x 36", 4"x 48" - or what? It depends on the overall size of
the parts and the limitations imposed by the size of your laser's cutting
table. Three, four, and six inches by 48" (cut in half) go nicely into a
12x24 table area, so what's the easiest? We prefer a 4"x 24" piece, and 3
such pieces can be loaded into the laser for cutting. However, if two of
your overall dimensions for a single bulkhead exceed 4", either you have to
use 6" wide wood or redesign the part into two pieces. As a practical
matter, 3.75" is the outside limitation on 4" wide wood to allow for warping
and imprecise machining of the wood stock at the mill. Set your CAD's grid
setting to 4" and copy in your parts to your new file, keeping the parts
within a 12"x 24" field on the screen. Wood's expensive, so nest them
together. To keep the parts from flying around while they're being cut,
breaks are made in each part to interrupt the cut. Ready to go. Turn on
the laser and the blower, load your wood and have the laser adjust the table
height to your wood thickness (i.e.: press a button!). Before you cut, you
have to tell the laser print driver how fast you want the head to move, and
how intense the laser beam should be. 1/16" wood cuts faster than 1/8" wood
due the different thickness. We got to he right answer only after trial and
error and created a resulting file of cutting drivers to cut anything from
Monokote to 1/8" plywood. Balsa can be unpredictable at times since its
density can vary from 4 to 16 pound per cubic foot. We try to use only
contest grade balsa, but even this varies greatly. Since the laser leaves
kerf just like a band saw, wood density plays a big role in determining how
accurate a part can be cut. The softer and thinner the wood, the wider the
resulting kerf. Sometimes the laser won't cut through if the wood is too
hard for the given speed/power setting. If you've done everything right,
the parts should slightly interference fit together, giving you a great glue
joint.

That's about it. I recommend that you try ModelCAD and try drawing some
parts. We can cut the parts at about $40 per hour and would be happy to
answer any questions.

Robert J Caso and William Doucet, TurnKeyRC.com, 610-369-0822

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

THE STORY OF THE CLUB HAT ...
AND HOW TO GET YOURS

by Ron Strobel

It was the winter of 1995. I found myself in Camden, Maine looking for a
gift for my flight instructor, Rom Boutin. I was aware that instructors
accept no pay for all the hours they spend teaching us "wannabe's" how to
fly, but I wanted to be able to get him something for the gift of flight
that he had given my dad (the Hawk) and me. I saw a sign in the window of
Camden Custom Embroidery that said, "We print anything on anything."

I walked in and asked if they could print a custom hat for me. I picked out
the style, the color and asked them to print V.F.S.S. on the top and Rom
Boutin on the bottom. I knew from experience that many times out at the
filed you see guys that you recognize but you don't necessarily know (or
remember) their names. The hat would help to alleviate that problem. While
I was there I also ordered hats for my dad and myself. When spring came I
gave Rom his hat, and soon afterwards the hat caught on.

This September I visited the shop again, and this time spoke with the owner,
Bill Dickey. He asked why the hat orders had stopped, and I told him that
collecting the money after the hats were ordered was the problem. He came
up with the solution. Simply pick up the phone and call 207-236-8626. Tell
them you want to order a V.F.S.S. hat. Tell them your name and credit card
information. They will produce the hat and send it to your by mail within
three weeks. The cost is $12.00 per hat plus shipping of $5.00. Not bad
for a custom hat! If you have any questions, Bill can be emailed at
<mailto:ccebill@tidewater>ccebill@tidewater

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

DECEMBER CLUB MEETING
by Warren Barrick

The Club meeting on December 10th was a wonderful experience, thanks to Bob
Engman and his marvelous presentation on sculpture. Bob showed a film on the
construction of his sculpture called "Flight" and simultaneously presented
slides showing prototypes and actual masterpieces that he has turned out
over the years.

Many members brought their wives and we all were enthralled with Bob's humor
and achievements. He explained that he "really didn't know what he was
doing" rather tongue in cheek. We all should be so fortunate and talented.
Many commented after the presentation on the fact that Professor Engman
accepted the commission on "Flight" so that he could provide his students
with some money to pay for their education. We are joyful that Bob's
aviation interests and modeling skills have made him a truly valued member
of the Valley Forge Signal Seekers. Thanks, Bob!

Jim Myers showed his skeleton of a Super Cub, and Russ O'Brien offered his
method of making lock nuts as well as how to construct skis for snow flying.
Thanks, guys.

Kudos to Al and Betty Campana who have been a big hit in setting up and
operating our self-sufficient coffee and doughnut operation. Their efforts
have made this mundane thing another attraction for our already exciting
general membership meetings. Thanks, Betty and Al!

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

JANUARY RAFFLE
by Joe Yalove

The following are the prizes for the next general meeting:

1. Craftsman 9 inch combination disc/belt sander. This is a stationery unit
which can mount on a table or a mobile cart. If you are working with wood
you need this tool.

2. Black and Decker 9.6 volt cordless drill/driver with a bonus electric
screwdriver and a holster carrying case.

3. Workforce combination 40 piece multidriver tool kit. If it can be turned
this will do it.

4. CA repair kit - includes 3 bottles of different grade CA and kicker.

5. A roll of red monocote.

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

VFSS AWARD NOMINEES

Nominees for Doug Davidson Award are Carl Sutton and Pat Taggart.

Nominees for the Technical Achievement Award are Mike Myers and Russ O'
Brien.

Club members will vote for the award winners at the general membership
meeting at the church on January 14th.

Be there and vote for your choice!

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

CLUB CALENDAR

Tuesday, January 7th -
BOG meeting at the church, 7:00 PM, Room 207. Budget for 2003 to be
deliberated. All new members should attend.

Tuesday, January 14th -
General Membership meetings at the church at 8:00 PM. Guest speaker Rob
Caso. Rob will inform us about laser cutting technique and CAD. Elections
will be held for VFSS Awards. Raffle and Show-N-Tell, as usual.

Tuesday, February 11th -
Annual Awards Banquet at the Camelot, 425 Mill St., in Bridgeport, PA. All
reservations and payments must be received by Carl Sutton by February 3rd.

Saturday, February 22nd -
WRAM Show in White Plains, New York. Bus trip from church to show. Tickets
$40.00. Contact Joe Weizer.

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

BOARD OF GOVERNORS

B.O.G. Term Expires End of 2003

Frank Butta
Tris Colket, Field Marshal
Rudy Forst, Membership Chairman
Nathan Marks, Chief Field Marshal
Alex Primas, Vice President
Bob Sudermann, President
Pat Taggart
Steve Trabosh
Joe Varallo
John Williamson

BOG Term Expires End of 2004

Tom Burns
John Carrigan
Clarence Evans
Steve Kolet
Harry Lawton
Al Marcucci
Ed Moore
Howard Peyton
Joe Saporito
Charles Swope
Joe Weizer
Joe Yalove, Raffle Chairman

OTHER CLUB FUNCTIONS

Rom Boutin, Field Marshal
Mike Estock, Field Marshal
Tom Greet, Sailplane Instructor
Gerry Keenan, Field Marshal
Mel Jones, Helicopter Instructor
Dee Messina, Interim Secretary
Walt Pierzchala, Sunshine Chairman
Art Rothstein, Field Marshal
Ed Snead, Field Marshal
Carl Sutton, Treasurer
Michael Myers, Webmaster
Marilyn Ayres, Editor, Hear Ye!


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


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