Notes from a first time Glider CD
by Jim Reith

Since I started flying in the early 70s, I've always tried to set a goal for what I hope to accomplish each trip to the field. In the early years it started with returning home with a repairable plane, then an undamaged plane and finally I got into specific tasks like landing on the runway. I took a few years off while starting my family and got back into it in 1988. Suddenly there were clubs around and people who knew how to fly well and new things to master. Soon I was hooked again and spending much of my time involved in airplanes. Some of the people from work started flying at lunch and we found a local field where we could fly 2 meter and handlaunch gliders. My first proportional plane had been a Graupner Amigo II with an .049 power pod and I really enjoyed flying it around. I got back into gliders with this lunchtime group and we started working with each other to help ourselves improve. It was a great way to relax in the middle of the work day. Soon we were "competing" amongst ourselves and during 1991 we decided to go to some of the local glider contests to see how good we really were. We had a ball but many of the contests were 2-3 hours drive away. The 1992 Nats came out to our section of the country and we decided to try our hand at it. One of the local power clubs had a small group that flew gliders in the morning before the club fun-flys. This club also sanctioned an open contest once a year. This past winter I was asked if I'd be willing to take it over and I said "Sure!" This article is a recount of my experiences and things that I would recommend people put time into if they want to have a successful contest.

Since I had been competing for a few years and had been to several contests that I liked (and a few I thought had problems), I had some specific goals that I wanted to reach. The first thing that I want people to remember is that regardless of what you do, Murphy will be your co-CD. The most successful way to get a contest going is to plan ahead for eventualities and not let Murphy surprise you. My first brush with Murphy was when the sanctioning forms were submitted. The AMA was moving so the forms came back later than expected. We had a "committee" to write the letters to places for prize donations and they wanted to include a copy of the sanctioning form with the letters. The committee decided that this was the year to update the letters. This further delayed the letters going out so by the time the early season glider contest came around, few glider relevant prizes were available. This caused me to go out and buy some prizes to fill in the gaps. I found all this out when I checked on the prizes with two weeks to the contest date, I managed to get a few manufacturers to send me gift certificates so we had some prizes. Point 1: make sure your prizes are in order while you still have enough time to do something about it. Better yet, handle the donation requests yourself. After all, Murphy will be sure to be on the committee.

Another consideration was the award plaques. I had incorrectly assumed that the prize committee had also taken care of that so I had to put in a rush order and was pleased to recieve the plaques friday before the contest weekend. When you fill out your sanctioning forms, you need to decide what type of contest you want to hold. Since our field is a small power field, we have throughput problems and can only run two winches at a time. In past years we have used sport winches and the launches have been anemic. I managed to line up several winches for the contest and luckily we had enough for what we needed. I also set out to find retrievers to use. There was one in the club and another was promised by one of the non-local people that called for directions (Murphy heard the call). With only two winches to run and two retrievers available, I declined an offer of a dirt bike to pull chutes. We have a less than perfect winch area so we had several line snags and breaks. This was helped by having several winches lined up. Point 2: Never refuse equipment that can help out at the contest. Duplicate equipment isn't extra, it's backup.

Since this is mostly a power club and doesn't have standard winch paths laid out, the winch area is mown the week before the contest. Murphy handled this task for me as well and I got a call late friday night that I needed to be at the field with the payment for the mower to have the field done. Point 3: If you need custom cutting done at the field, get it done early in the week. In the future I'll have it done the weekend before and then go out the day before the contest and personally touch it up as needed.

In previous years, our winchmaster has been down at the winch area for most of the day and gotten pretty sunburned. Remember that these people are volunteers and make sure they have everything that they need. This year we set up a canopy at the winch area so they could get out of the sun. I thought of having a small cooler for sodas after the contest and will provide that next year since our launch area is away from the main CD/impound area due to our field setup. We also had a pair of canopies at the impound/CD area. The impound was covered to shade the equipment. This worked out well but for the wrong reason. See, it seems Murphy new the weather gods and while we had little wind, we had a pretty consistant drizzle during sections of the contest. The canopies provided refuge and kept the equipment dry. Another thing to consider is staff. Running just about any size contest is something that can't be done alone. I was fortunate to get some power fliers to come out and help run the contest. I also had help from my family and the more hands you have, the smoother things go. The best thing to do is to delegate everything and then you can handle the little emergencies that WILL come up during the day. Minimum staff I'd recommend is a winchmaster, score tabulator and impound person. Doubling up on these positions allows people to take a break. Your job as CD is to make sure that things keep moving and help out in the bottle necks. Even though it is tempting to take one of these jobs yourself, resist the impulse. You'll be busy enough filling in the gaps when the unexpected things happen. Nothing is more boring for your contestants than waiting. Point 4: Get a commitment from people to work the contest and verify that they can as the date approaches. Have extra people scheduled and assign tasks the morning of the contest. Even people that can only stop by for a few hours can help out and give people a break. The more people you get to help out, the smoother things will run.

When the contest day arrives, get to the field early to set up. I made signs to post on the access roads so contestants not familiar with the field could find it. This worked out well and we actually had spectators for the first time. Try to have some of your helpers there to help set out the winches and setup registration. When people start to arrive, start processing registrations so it doesn't backlog. Figure out how you're going to do the scoring for the rounds and have the forms made up ahead of time. Have twice as many forms as you'll need and leave plenty of room on any you make so you can read the scratchings you will find on them later. Have plenty of pens or pencils so people can fill out the forms and do the individual flight scoring. Keep all the score sheets that get turned in in case you need to go back and settle a dispute in scoring. Have the timer for the flight put his/her initials on the scoring chit. Most people that come to thermal duration contests have a stopwatch with them but it never hurts to have a few extra available in case someone needs a timer. Point 5: Figure out what you need for signs, fliers, scoring sheets and get them made up and copied well in advance.

The most important time of the contest for the CD is the pilot's meeting. At the beginning of the contest you should determine the tasks (sometimes you need to change this based on the day's weather) and let the pilots know. You also need to tell any visiting pilots any special rules for the field you are using. Make sure that they know the scoring system you are using and what needs to be entered on the scoring chits. Make it clear that it is the pilot's responsibility to verify the timer entered the proper information on the chit BEFORE it is turned in to the scorekeeper. Make sure your scorekeeper understands how you want the scores tabulated. Too many times I have seen times entered as 5:23 only to have the scorekeeper enter it as 523 points. Remember the minutes are only 60 points (if you use the point per second system). Point 6: Have a set of notes to read at the pilot's meeting so you don't forget any points. It is difficult to clarify rules once the contest has started. Always ask if there are any questions once you're done.

At the end of the day when you are done with your flying and need to get things in order for the awards ceremony, try to have something to occupy the contestants while you do the necessary preparation. What we have found is that several contestants bring HLGs to fly at this time so we've actually organized a HLG event to fly during final standings calculations. This has worked out well and with a format of 5 tosses in a 10 minute window with a group of 4-8 pilots (depending on frequency conflicts, you should try to keep the groups uniform in size), we've had a good time both flying and spectating these events. Make sure to thank all the helpers as often as possible and get out there and have a ball. Final point: Double check the scoring sheets to make sure that the awards are given to the proper people. Once you hand them out it's difficult to correct mistakes.

Don't be afraid to volunteer to run a contest. Small club events are the easiest and most forgiving to run but the bigger contests aren't much different. Once you get a list of things to get done (as this article outlines) you can expand your helpers to cover any size contest. The best way to improve local contests is to hold one and get yourself involved. If you have any additional suggestions to pass along, please drop me a line as I'm still hoping to CD the ultimate contest for the fliers in my area. You can contact me at Jim Reith, P.O. Box 863, Southbridge, MA 01550.

Low cost, high tech wings. (April 1994 RCSD, page 12)
by Jim Reith

Everyone that catches the R/C "bug" spends a lot of time drooling over the latest and greatest planes in every catalog and magazine that comes their way. Sometimes it seems that if you want to be competitive and get yourself out of the middle of the pack, you need to apply for a second mortgage. I'd like to take you along a route to get to that high tech ship without snapping your shoestring budget. What I'm about to describe is a way to take an existing plane and make it more competitive without breaking the bank. I used this method to upgrade a Gentle Lady several years ago and was asked to write up an article to help people save money while learning.

One of the things you notice in the dream ships we all see is that they are predominantly foam wings. There are several excellent foam cutters commercially available but if you're on a tight budget, they might be out of reach. When I cut my first foam wing, I used a cutter similar to what I'm about to describe. I still use one to cut up the big foam blocks into blanks. First we need to find a piece of wire which we can heat up to cut the foam. Sig sells nichrome wire which you might be able to get at your hobby store, stainless steel fishing leader (uncoated) is available from tackle stores, or my current favorite is old braided control line flying wires. Next we need a power supply to heat the wire. This is preferably an adjustable supply and I have used model train transformers in the past as well as transformers plugged into the light dimmer outlet in my house. Make sure you don't damage the dining room table or you won't get out flying for a while! I currently use a power supply I built for about $30 out of parts from the local Radio Shack. I used one of their 2 amp 25.2 volt transformers and some lights, switches, terminals, an enclosure and a circuit breaker. If people are interested in plans for this they can send me a long SASE and I'll forward them copy. Next we need something to hold the wire while it's hot. A simple bow can be made out of a piece of wood and some music wire. Go to your hobby store and get the thickest piece of music wire you can find wheel collars for, I try to use 5/32" or 3/16". Pick up 6 wheel collars as well. Get a piece of wood that's about 2"x2" (I use half of a 2x4 that I split the long ways) and about 6"-8" longer than the biggest core you'll probably cut (I try to stay under 36" cores to keep quality up) and 2" in from the ends drill holes the size of the music wire pointing outward at a 45 degree angle. Next, take your music wire and cut it in half. Install a wheel collar on each half about 4" from the end and slip these wheel collar ends into the holes we just drilled so the wire is sticking out angled away from the center like figure 1.

[picture of unstrung cutting bow]
Now put a wheel collar about 1" down from the end on each free end. Get your cutting wire and make a loop at one end and crimp it with a piece of brass tubing. Make sure that the edges of the tubing are smooth so they don't cut the wire off. The loop only has to be big enough to slip over the music wire. Now make another loop in the wire the same distance from the first one as the distance between the holes in the wood. Now put one loop over the end of the music wire and slide it down to the wheel collar and then bend the wires inward and slip the other loop over the other piece of music wire, The wheel collars will keep the loop from going down to the wood and you should add two more wheel collars to keep the loop from slipping back off the ends. You now should have a bow that looks like figure 2 with the cutting wire across the top.

[picture of strung cutting bow]
The reason you need to put the wire under tension is because it stretches when heated. If you use too much tension the wire will stretch and not return to it's normal size when cooled. Eventually you will stretch it to where it becomes too thin and breaks. If you don't use enough tension you'll get wire sag in the center when you try to cut cores. I find that the nichrome and stainless steel wires stretch over time and have had much better luck with the braided line (around 500 cuts per wire). One other thing I did to my cutter is to install a momentary push button switch in the center of the wooden handle. This allows me to control the power and hold the bow with one hand without having to reach over to the power supply. This has worked out very well since I often use it when I'm alone. I complete my bow with a set of 16 gauge power leads with alligator clips on the end. I made mine about 12 feet long so I can move around in my shop. You can hook the power leads up via the central push button or directly to the ends of the music wire protruding from the back of the wood handle.

Now that we have a bow, we need something to cut. First thing we need is some foam. You can usually find foam at the local lumber yard to be used as insulation (at least up here in the northern climates where we see snow in the winter). There are several types and weights so you need to decide what you want to use. For most applications that will involve sheeting, 1 pound per cubic foot white expanded bead polystyrene will work well (ask for white beadboard at the insulation section). If you intend to use fiberglass to sheet your wings then you might be more comfortable with extruded polystyrene. Dow Grayboard is a good choice here.

Now we need a pattern to cut it to. I've used several things for my templates but I usually go back to a good grade (5 or 7 ply) of 3/32" plywood. Many articles talk about attaching the templates to the foam blank but for production work, I find it easier to attach them to a piece of wood for a base. If you try to pin the templates to the cores the pressure of the bow on the templates can move them and cause you to not cut an accurate core. I use a pine board cut slightly longer than the length of my core and use drywall screws to attach the templates to the ends. To cut the templates I usually glue a paper template (either computer generated or a photocopy from the plans or a book) to the wood (one for the top and one for the bottom) and then draw lines extending the trailing edge outward in a straight line. I also mark the templates at several points along the template and number them from the leading edge back. 8 is usually enough and is simple to do since you just divide the length in half, and those halves into quarters and then finally those quarters into eighths. This is easily done by folding the paper templates in half three times before attaching them to the wood. These marks are your cutting stations and are very important for getting an accurate cut. I cut the templates out near the line and then use a sanding block to bring them down to the exact shape. Then I coat the edge with thin CA and let it cure. I lightly sand the CA'd edge and recoat. I do my final sanding with 600 grit paper and run my fingernail over the edge to check for nicks. Any roughness will show up as a ridge in the cores so take your time. I then clamp the top and bottom templates together and drill 1/8" holes where I'll screw them onto the base. This will align the templates when I change them. Now screw the bottom templates onto the base being very careful to get the two ends align to the same incidence. Sometimes I'll draw a centerline on the top templates and install them first to position the holes making sure that the centerline is the same height above the base on both ends of both templates. With the holes done in this manner you can remove the top templates and install the bottom ones knowing they are aligned.

When we discussed the bow we mentioned line sag. No matter what you do, you'll always have some. It might be 1/16" or more or less but there's always some. This sag is due to the center of the wire being pulled back by the drag of the cutting process. It tends to be worst at the end of the cut so I generally start cutting at the leading edge where the curves are more pronounced. The reason we extended the trailing edge in a straight line is so that the center of the wire will pull out of the foam at the same level as the two ends and give you a straight feather trailing edge. You want to cut the bottom of the core first so that the core settles into the bed and you don't have to compensate for the wire thickness (kerf).

Let's get cutting! Find a friend/spouse/older child to help out. Explain the following to them. When you are cutting you want the wire to stay down on the template and to move as smoothly along the template as possible. You don't stop and you keep moving at a steady pace. I usually have one person calling out positions and the other person keeping up on their end. It usually sounds something like, "coming up on one...half way to two... at two" and so on until you're done.

Stabs and tiplets are higher taper than wings and sometimes you can cut them with just one template. If you look at the shape, it's really just a triangle with the outboard point cut off. Many articles talk about using a wire with a handle at one end and a pivot at the other. You put the pivot out at the "cut off" point of the triangle and the template at the root end. One of the problems I have is maintaining tension on the wire and pressure on the template and smooth motion along the template. Here's a simpler way that removes one of these tasks (maintaining tension) and uses the bow you've already made. I mount my template on the end of a board and draw my lines along the leading and trailing edges to find the pivot point. I mount a block of wood near the pivot point so that I can attach a scrap of plywood that will stand up parallel to the template over the pivot. I then saw a kerf down into the plywood to the same height as the centerline on my template. I then slip one end of my bow into the saw kerf and hold the other end on the template. You can then cut out the tiplet/stab in the normal manner with the plywood pivot holding the opposite end in one place. Geometry will take care of the inner "template" and the bow will take care of the tension. You just have to follow the template and keep the bow moving at a constant speed.

Now that you've got a set of cores, you need to figure out how you want to cover them. Balsa and obechi are the normal materials but sometimes you want to try out something in a disposable form. I've used colored poster board (5 big sheets for a dollar) on a set of HLG wings to try out different airfoils. There was a recent article in one of the magazines about using brown paper and white glue so you don't have to invest $10 in wood to try out an airfoil on a wing. Works great for disposable slope combat ships as well. Vacuum bagging is all the rage at the moment and does do a nice job on wings but it involves equipment and fiddling and can be a project in itself. Before people used vacuum, they used weights. The easiest method for holding the skins on the cores while the glue dries is to put a board over the core/sheeting "sandwich" and stack books and bowling balls and other weight to "press" them in place. To set up this "sandwich" you need to put the bottom core bed on a sturdy flat surface, cover it with wax paper. Then take your wing skins and tape the trailing edge together with a slight gap so they will fold over flat. Coat the inner surface of the skins with your glue and let it soak in a little and then scrape most of it back off. Now put any trailing edge reinforcement on the glue surface and position the core on the skin with overlap all around the edges. Fold the top skin over and place it on the wax paper in the lower core bed. Put another piece of wax paper over the top and put on the top core bed. Now put a board on top to press this sandwich together slightly. Before you start piling weight on the board, align the leading edge of the core with the leading edges of both skins at both ends. Once you get it all in place, start piling books or other weight evenly across the top. For a normal wing you want to use 50-100 pounds per panel. Water jugs can also be used (water is about 7 pounds per gallon).

For glue, I've found an interesting source of epoxy that I can get at my local lumber yard. I have used a two part, clear bar top finish. When you open up the package it warns about epoxy resins (but doesn't mention it on the outside), it mixes 1 to 1 and cures within 24 hours. I have also tried F77 spray contact cement but I really prefer to use an epoxy. To keep up with our low cost theme, I've found that using clear plastic "on the rocks" glasses as mixing cups works well. To mix proper amounts of epoxy, I put one cup inside another and mark the level of one part I need on the outside cup. I then fill a second cup to this level (with the first cup on the outside again) and pour the first cup into it and mark the 1-to-1 both part level on the outside cup. I then carefully drill small holes, the side of the tip of a felt tip marker in the outside cup and I can then put the pen into the holes and rotate the inside cup to make the measuring marks. Every time you need a new mixing cup, you just pop it inside and mark it. Always the same. Always accurate, cheap and disposable. If you use different amounts of epoxy for different jobs, just mark more levels at different points around the outside cup and you can make the right measuring marks for the right job. I always make the marking holes vertically aligned so I always know which pair are which amount.

That's about it. Low cost high tech at it's finest. You can always spend more money and the commercial cutters are great quality but sometimes you just want to try something out and this is a good low cost method that will get the job done.

About the author: Jim Reith runs RA Cores and cut his first foam cores in the early 70s when he discovered he didn't like cutting out ribs when scratch building. Eventually he built more sophisticated cutters and started doing cores for friends and finally went commercial in 1992 when a friend used him as a source in a construction article in a national magazine. Jim's latest cutter is completely computerized and template free. He can be contacted at P.O. Box 863, Southbridge, MA 01550 or (508) 765-9998 evenings

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Created: Sunday March 26, 1995
Last updated: Sunday May 26, 2002

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