CLOUD 9 R/C NEWSLETTER 3/96
Where does the time go? Right after Christmas I was gathering material for the first CETO club newsletter of 1996. Then came problems, one after another. The first one, on Jan. 3rd, was that my wife, Lillian, was severely injured in a fall on the front steps of our house. The result was broken bones in her left arm and foot, plus bruises all over. For two months she was house bound, with me doing most of the household chores.
In the middle of all that we were experiencing a series of snow storms, ice, rain, and very cold weather. Now. over two months into the new year Lil is still undergoing physical therapy three times a week and although she is improving steadily, she's a long way from normal capability.
This, therefore, has been far from a Happy New Year so far and I figure that I'm about two months behind doing all that I wanted to. Well, enough gloom and doom, it's time to get going on all that's been neglected, particularly the newsletter. Meanwhile my apologies for the delay and problems with Cloud 9 service.
With the help of a longtime friend, Howard Kuhn, it hasn't all been a total loss-- the newsletter has a new look. He has taken my word-processor typing and dressed it up with his expertise at desktop publishing. Basically, I give him the words and sketches and he organizes them and prints out a much prettier version of the newsletter than I could do.
The new name "Cloud 9 RC Newsletter" represents an expansion of the original newsletter concept. At first, the CETO newsletter was intended to show purchasers of the Czech-made CETO what more could be done with it, relate experiences with it, pass on information about possible improvements or problems, etc. However, it quickly developed that the CETO radio is only part of the subminiature RC scene. From this grew the need for a small mail-order operation to provide items that could be used with the CETO and other small radios. Thus Cloud 9 RC was born, operating from home very much like back in the 50's when I managed the "Control Research" mail order operation.
All of this has now merged into a Cloud 9 RC activity which is a mixed bag of building and flying little models, finding sources of unique supplies and accessories, exchanging information, writing magazine articles, and trying out ideas on the workbench. Thus life is busier than ever and there aren't enough hours in retirement to do as much as I'd like, when I'd like it-I'll do what I can when I can, to help myself and others to advance the state of the art.
Enough background. Now to what this newsletter is all about:
CABLE TYPE CONTROL SYSTEMS
One of our subscribers (George Pearce- Chesapeake, VA) asked about what kind of thread is best for figure-eight type rudder hinging. Here's the answer from an expert (Joe Wagner, the "Dakota" man from New Wilmington, Pa):
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I have one comment to make about your recommendations for sewed hinges and thread control cables: DON'T use regular sewing thread! I've employed "baseball stitch" hinges regularly on both U-Control and R/C models since 1950, and I can tell you that the ONLY kind of thread that will stand up to the constant flexing of control-surface "hinges" is nylon or dacron. I've been using Sig's dacron 1/2A control-line thread for the past 15 years or more, without any failures.
Previously I tried mercerized cotton thread and also polyester. They worked for awhile, but didn't last more than one flying season before needing replacement. By the way, I've found that the quickest and neatest way of installing sewed hinges is to pre-drill the holes. I made a "drill jig" which produces neat evenly spaced stitches, and makes the "needlework" much easier."
Another expert Woody Blanchard- Hampton. VM advises that using strands
of Kevlar or Carbon-Fibre is good. He says "Single strands (or several
twisted strands) of either of these materials make excellent pull-pull
cables for our Micro R/C models: very high modulus of elasticity (minimum
stretch or sag) for precise centering and control response. and extremely
light weight along with the ability to "stay snug" while circling about
cylinders (rudder posts) of 1/8" diameter, because of the infinitesimal
diameter of the cable.
Sidelight: Woody also says: "The CETO Receiver and the CETO Actuator bought from you work fine with my old Min-X pulse Transmitter".
BACK TO PULL-PULL CABLES
One problem with them, especially with the relatively weak CETO actuator, is getting the cable tension just right- not too bad to do on a bench mockup, but sometimes frustrating to do on the model. Here's a simple way to provide an easy means of tension adjustment:
The cables are initially fastened with a little slack. Then, by adjusting the vertical arms of the music wire bracket outward slightly, the tension can be set as necessary for snappy actuator action with minimum "slop" of the cables.
If you have gotten some of those Cute and tiny little blue pull-push switches from Cloud 9 RC, be aware (if you haven't found out already) that they are unreliable. My recommendation is to not use them. Instead, you send them back to Cloud 9 to get better replacements in exchange for new very small slide switches.
I've discontinued the blue switches. The new little slide switch is also single-pole double-throw. which allows for a simple circuit modification for charging that saves constantly having to plug and unplug the CETO wiring, which in time often results in broken plug connections.
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Note: If you simply remind me that you bought one or more of the blue switches I'll send an equal number of the slide switches. Or, I'll give you credit toward any other items at the original blue switch price (75 each or 3 for $2). Meanwhile, I'm sorry these little blue switches got into circulation via Cloud 9 RC; a mistake I hope won't be repeated.
Fritz Mueller (Columbus, GA) is widely known as a "Guru" of super small, super light models powered by C02 motors. Two pages of his thinking are included in this newsletter as "food for thought". One of his subjects concerns the CETO radio and the other is about C02; both gems of information are based on his extensive experience with little models. One of his jewels of information is that a P-30 type of free flight model (or R/C) is actually lighter with C02 power system than with rubber power!
It is fairly well known that a C02 motor system is lighter than an equivalent electric motor power system; very important for indoor R/C. So C02 is very much worth looking into for very small models (and bigger ones too). That's not to say, however, that C02 does not have problems. But they're manageable. I hope that between Fritz and myself (and anyone else who cares to join in the discussion) we will publish more information in future newsletters to broaden the world of C02.
Incidentally, to my knowledge, the guy who has done more flying than anyone else, with the combination of C02 models and CETO R/C is Henry Pasquet of Ellsinore. Mo. You will be learning more about Henry's achievements and thinking in newsletters to come, also this one. For example:
ANOTHER CETO BATTERY ALTERNATIVE
Henry Pasquet put me onto trying Radio Shack's # 357 Silver Oxide cells in place of the Varta NiCads that come with the CETO. They are not rechargeable, but they seem to last a very long time (no test results yet however) Henry thinks they might last a season's flying and for him that's a lot of time in the air.
The 357's are exact physical size replacements for the Vartas. Henry is using only two for 3 volts, but I prefer three for 4.5 volts. Either way no recharging is involved so that's a great convenience. The cost is $2.79 per cell and time will tell if the cost vs. life is a good trade-off in comparison with the 30 mah Varta cells. More on this alternative as we gain more experience with the 357's.
Incidentally, I have also played with using little Lithium cells in place of the NiCads. They're small and light enough and are rated at very high capacity (160 mah), but they don't seem to hold voltage very well. A brand new Lithium rated at 3 volts drops to 2.5V under the very light CETO actuator load. I'm trying to learn more about Lithium and will advise what I find. Meanwhile I may have to use a 6 volt Lithium (which is small enough) in order to maintain more than 3 volts under load. If any of our subscribers can tell us more about Lithium I'd appreciate hearing about them.
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Many of us are concerned about weight in our models and measuring in grams is particularly helpful. The stock CETO airborne system weighs 14 grams, or about half an ounce. In comparing components of a system, it's usually easier to talk in grams, whereas when looking at total model weight it seems easier to talk ounces.
Some of us are using electronic scales to measure either grams or ounces.
You can spend hundreds of dollars for electronic scales.
but that is not necessary. I bought a Fortrec electronic scale mail order for $38. It has worked very well for several years. except for one annoying problem. It goes through pen-cell batteries more often than seems reasonable, even though it has an automatic battery cutoff. Solution: install a small toggle switch in series with one of the internal battery wires. This enables me to switch on and off only while weighing. I haven't replaced a set of batteries since I installed the switch. Credit this idea to Jim O'Brien of Tampa, Florida.
TWO CHANNEL MICRO
Fleming N. Hanley Jr: N.Palm Beach, FL) writes: "I took a Wienkler VALLEY FLYER 22" span and added polyhedral, giving now 29 1/2" span. I changed rubber power to .020 Cox engine. I plan no throttle but have ailerons and elevator for RC. I can limit fuel to control engine run. Weight is .92 with gas tank (presumably, engine assembly, in ounces). I can remove the tank and use fuel line for supply maybe, for less weight.
The best I have found is staying with FM for less interference at the field: Hitech HFS-O4 MI (receiver) weighing .94 oz. and two HS-60 servos weighing .49 oz each. I have thought about removing the receiver from its case and wrapping in foam to keep the weight down. If you know of a lighter weight FM system let me know; I prefer FM and being able to fly outside. PS: I am familiar with CETO indoor use.
(JW comment): Aside from the FM aspect, several people (including myself) have used the Hitech (also known as RCD) "Shredder" 2-channel receiver, made for model cars. Mine uses a very small Cannon servo for rudder and a tiny speed control for the electric motor. Works well and it's nice to have crystal control on any of the 27 mHz channels. Not as small and light as the CETO system, but with two proportional channels the Hitech system is more versatile.
TWIN TURBO MODIFICATION:
I have stripped the receiving system of all the black plastic, including propellers. The end result is a receiver, battery pack, and two actuators, with a total weight of about 1-1/2 ounces. Again, higher than the CETO but with two independent channels.
I use the previous prop motors as magnetic actuators, each limited with stops to about 180 degrees of travel. Lots of actuator power, lots of control throw, but more battery drain than desired (tolerable, however, since the controls are used intermittently, on a bang-bang (full throw) basis. I'm using one actuator for rudder, one for elevator. No thrust control, using C02 for power. The motors are apparently the Same as Kenway sells as the KRl-D; made by Mabuchi.
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The main attraction of the Twin Turbo system (besides the two channel feature) is the low cost- the whole radio control system including the two stick transmitter, but less batteries) is only $ 12.95! Range is a problem (OK for small indoor sites) but we're working on that. (Instead of regarding such things as negative. I consider them as challenges- problems to solve by good old American ingenuity. That's what makes this fun!).
BIGGER IS BETTER
Maybe. It depends upon what you like. For those who want conventional servo operation, the Hitech's system is one way to go; another is the Cannon system. The latter is more expensive but is the nearest thing to the kind of R/C systems we use for models of four or more feet of wingspan.
Three foot span models are practical for the Cannon system and up to five channels are available. Cannon's new Ultra system is their smallest yet. But it's more expensive, can only be ordered from the factory. and it takes months to get. Meanwhile, Cloud 9 R/C has been authorized to sell Cannon's Micro-Elite system, only slightly bigger, a little cheaper and available sooner; probably a better compromise for those who want a complete ready-to-go RC system with 'normal' servos.
THE MICRO-ELITE CANNON RC SYSTEM
This 1996 Cannon Narrow Band system is very small. The airborne components are among the smallest and lightest available anywhere ready to use as is, with up to 5 channels and with conventional proportional control (non-pulsing) true servos. The receiver and servos are considerably smaller than a standard U. S. commemorative postage stamp.
Each complete Micro-Elite system consists of a Transmitter, Antenna, Frequency Flag, Dual Charger, Receiver, NiCad batteries of choice, requested number of Servos, Servo Mounting Plates, and Aileron Tray (4 and 5 ch. only). Unless specified otherwise, the standard receiver battery pack supplied with 2 or 3 channel units is 110 mah, or 270mah for 4 or 5 channels. Either pack is available on request, or lighter 50 or 75 mah packs can be supplied. All battery packs available at the same price, but plug type must be specified: Micro (red or black) or Deans.
Everything, including transmitter (See above for list of parts)
Prices are based on 72 Mhz, 2 Axis transmitter control sticks
2 Channels, 2 servos $278.95
3 Channels, 3 servos $329.95 (prices are not current)
4 Channels, 4 servos $381.95
5 Channels, 5 servos $390.95
Add $20.00 for Single (3-Axis) Transmitter Control Stick.
Everything, except transmitter
2 channels, 2 servos $206.95 (prices are not current)
3 channels, 3 servos $247.95
4 channels, 4 servos $291.95
5 channels, 5 servos $304.95
Allow for 30 day delivery time when ordering via Cloud 9 RC, but we will try to deliver sooner. Advance payment for shipment must be made. We regret that we cannot process credit card orders at this time- payment by check or money order is required.
CLOUD 9 NEWSLETTER----JULY, 1996
APOLOGIES-ONE MORE TIME
Again- another major delay in getting out this newsletter. I think- and hope- you will agree that the wait has been productive. Besides this double size issue, with twice as much "stuff" to bring you, there is another Double-feature factor involved.
After telling you about efforts to come up with a better actuator than that made by CETO, we now have three (!) different alternatives to tell you about.
Fritz Mueller (Columbus, GA) and his "BIRD"
He has produced an incredibly efficient super-small and light Built-In-Rudder-Device (BIRD- my terminology). Weight just one gram! It's low voltage and low current drain, too- only about 30 ma on 3 volts. And it's more powerful than the CETO!
It comes with the rudder, ready to install in your model; no linkage required. Simply glue it on to the trailing edge of your vertical fin and connect the wires to your CETO receiver. The rudder has lots of throw, excellent power, and good size: 5/8" x 2 1/8" (1.3 sq. inches). While they last (Fritz has made a few by hand while he looks for someone to produce more) they are available through Cloud 9 RC for only $30, postpaid. At 1 gram and with only 3 volts required, Fritz' BIRD is suitable for Peanut size models and up to 30" wingspan. For more about this actuator, see Fritz' pages in this newsletter.
THE CLOUD 9 R/C MICROBUG
This is about the same size and weight of the CETO, but is much more powerful at the same voltage (3.6) and current drain (35 ma). It's a little bigger and made for heavier duty than the BIRD and is probably more suited for outdoor use- good for models from 24" to 36" wingspan. It's available from Cloud 9 RC for $25, postpaid, comes wired with a CETO compatible plug so that it can be directly swapped electrically, with the CETO.
MORE POWERFUL CETO!
We can now modify existing CETO actuators for much more power, without any increase in size or weight. Externally, the modified CETO looks identical to the regular one, except that it has more control movement and more power.
The modification is simply the substitution of a smaller but more powerful internal magnet. This produces more movement, about 3/16" instead of the slightly less than 1/8" of the regular CETO. If you would like to have your CETO actuator modified just send it and $15 to Cloud 9 RC- allow about 2 weeks for it to come back to you.
MORE ABOUT CETO ACTUATOR ALTERNATIVES
Besides Fritz Mueller's ultralight and ultra small (but powerful) actuator, and modifying the regular CETO actuator for more power, Cloud 9 RC now has its own actuator to replace the CETO. It's about the same size and weight (3 grams) and has the same current drain (30-35 ma), but has much more power and movement (3/16-1/4").
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The parts cost is small (only about $6). But, due to the labor involved, for Cloud 9 RC to make and sell them, the price has to be $25. Without any real efficiency, it takes about 2 hours to make one. I'm not sure yet that I want to spend a lot of time making a lot of them- I'd rather spend my time experimenting with all kinds of stuff, rather than be tied down to doing just one thing.
The interesting thing, to me, about this new actuator is that there are several variations of it so far. But the simplest and best one at present is a solenoid design. It uses a solenoid rod (fancy name for about a half inch length of an iron nail) which slides back and forth in the center of a small coil. In the signal off position (full over to one side) there is no current drain (like the CETO). With signal, it snaps over to the other extreme position- about a quarter-inch stroke. It pulses well, snapping back and forth with authority.
Like the CETO, a small 'bias' magnet is used to push the solenoid rod to one side, opposing the magnetic force of another small magnet on the rod. Then, when current is applied to the solenoid coil, the polarity is such that it overcomes the signal-off bias magnet and snaps the rod to the other end of the linear stroke. Actually, three small magnets are involved, one each on opposite ends of the solenoid rod and the third one off to one side.
When I referred to "we" at the beginning of this subject, that means
myself and Roland Schmitt of Ft. Worth, Texas. The basic design is
something I dreamed up, but Roland came up with the coil to make it
practical- one from a three dollar ($2.99) five volt Radio Shack relay. Roland's version is shown on the right.
Note that it has the bias magnet on a screw so that it may be moved
closer to or further away from the coil- this is to permit adjusting
the 'bias' to suit the voltage applied to the coil and to adjust the
amount of magnetic force holding the actuator in the "off" position; a
balance between the two factors is necessary for proper action. Roland's version allows various voltages to be used: from 4.5 down to as low as 1 volt. At the higher voltage a full 1/4" stroke is obtained.
The Cloud 9 RC version, shown on the left, is a little simpler and smaller, also a little lighter. The bias magnet is fixed and mounted to the coil. It works well over a range of from 3 to 4.5 volts, so the normal 3.6 volts used for the CETO receiver operates the actuator well, right down to the voltage which will no longer operate the receiver reliably. A 3/16" stroke is provided.
For those who want to try building their own solenoid actuator, be aware that Radio Shack has two 5 volt relays. The best one for our purposes is the one with a 70 ohm coil (part no.275-243) The coil is perfect: small (about a 3/8" cube) and light. The only problem is that there is more work in getting the coil out of the relay assembly than in making the actuator after you have the coil in hand.
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With real mass production it might be worth having the coils made for us, but for now stripping the relay seems best (I hate winding tiny coils with the very fine wire involved!). On the other hand- and a word of warning to anyone inclined to build the actuator- it's easy to ruin the coil in the process of stripping the relay. You might also go through two or three relays to get one actuator made, spending a lot of time in the process. Regardless, I have no problem with people making their own versions of the actuator- feel free to copy it!
The actuator motion is push-pull, which means that a push-pull rod type
of linkage between the actuator and the rudder is most natural and works
well. But the actuator is so light, it also works well mounted directly
under the rudder, with a simple wire linkage. Either way, the action is truly snappy and able to drive rudders much larger than typically used with the CETO actuator. Note: the actuator pulses well at up to 3-4 strokes per second (maybe higher but it hasn't been tested for maximum rate).
FIGURE 8 HINGING REVISITED
Generally, the hinging of a control surface by some form of thread, or cord, or cable, in a figure 8 pattern, is a very low friction arrangement. However, this is true only if the threading is not done too tightly. If pulled tightly, to eliminate "slop" completely, the hinging can add friction unnecessarily- the threading should be done only as tightly as necessary to minimize "slop", without binding of the control surface movement.
After completing the thread hinging, the rudder action should be checked without any connection to the actuator. A simple way is to simply wave the fuselage back and forth. The surface should flop freely from one side to the other. If anything, a little "slop" is better than tightness. The important thing is to not waste actuator power-- the CETO actuator doesn't have any excess power to overcome friction.
MORE ON THREAD HINGING
Tom Ailes, of Valparaiso, Indiana, says: "There is a very inexpensive source for this type of hinge that I have been using for 30 + years without any failure. Use braided fish line (either Nylon or Dacron) that comes in spools of 50 yards for $2.99. It comes in pull-test strength of 8lb to 40lb and is manufactured by Mason Fishing and is available at most sporting goods stores."
TWIN TURBO TWO-CHANNEL SYSTEMS
Fran McElwee (New Jersey) says: "I've been playing with the Twin Turbo system and wondering how they got two channels. We would have loved to have that back in the 50's! I was playing with it with a bang-bang setup
like you mentioned." Me too, Fran, with a new twist: I'm using the solenoid actuator without the bias magnet, using a light centering spring to hold the solenoid rod in mid-stroke with signal off. Then the actuator goes to full stroke in either direction according to transmitter control stick movement. With two solenoid actuators, their total of only 6 grams weight is less than one of the Turbo motors and the total full-over current drain is only 70 mils, much less than that for one of the original motors. It's really neat to get four control motions from this setup.
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STILL MORE ACTUATOR ALTERNATIVES
Dennis Van Orman (Altoona, Pa) is using one of the old tiny German-made Bentert actuator with his CETO receiver. He says it works "just fine", even though there are only two wires out of the CETO receiver, as opposed to the three that came out of the original Albin receiver. This suggests that we could try all kinds of old actuators with the CETO receivers. I'm thinking, for example, of trying one of the original very small Aerotrol escapements. This would provide plenty of power to drive a rudder on a gas powered outdoor RC model. The main problem would be the higher current drain of typical escapements. But such a larger model could carry bigger batteries. Food for thought.
FULL SIZE PLAN
Fran McElwee (S. Plainfield, NJ) has been doing tiny planes for many years. The plan in this newsletter, for example, was published way back in 1973! Shown with a Cox .010 gas engine, his Mini-Mini Saucer would
probably do well with a tiny C02 engine, like the Brown Al3. His original Albin receiver and Bentert actuator can be directly replaced with the CETO receiver and Fritz' BIRD actuator, with 3 volts of battery power.
It's amazing to realize that Fran's model has only a 4" wingspan. A modern version, as noted above, should weigh less than 2 ounces, maybe only 1 1/2 ounces. Fran also has a 6"span version that weighs 5 1/2 ounces, using a Cano receiver, four 50 ma cells and a Cannon servo, Cox ..010.
MORE FROM FRITZ
With his contributions, this is getting to be as much a Fritz Mueller newsletter as mine, but that's fine with me-- he always has something interesting to say. His piece headed "Dreamland" is what we're all about: little RC.
Note the little servo he describes; also the little 2.6 gram superhet receiver from Austria. He also talks about flying indoors, with some good how4o information. And he tells about an outdoor experience with a C02 motor and the CETO actuat6r.
DON STEEB WRITES
More interesting stuff from a subscriber. Some excerpts: "I built and flew indoor RIC back when the first CG 3volt, direct drive escapement-receiver became available. My third model was the most successful. It was a pusher with a Cox .02 using a disc in front of the prop to reduce (!) thrust. The plane was a Primary Glider style about 3 ft. wingspan weighing about 5-6 oz I had one memorable crash, when with limited control the plane did a wingover and went through the basketball hoop and sheared the wings off, crashing to the gym floor and busting a new engine. "I will send you specs and pictures of a new plane using the (Twin) Turbo outputs for Rudder and Elevator, with Pager motors for the actuators. Approx. 36" wingspan weighing 2.75 oz."
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SOME BATTERY TESTS
Using three Radio Shack 357 Silver Oxide (non-rechargeable) cells the same physical size replacements for the CETO 30 mah Varta NiCads, pulsing the CETO system at about three cycles per second (old Testor's
transmitter) operation was fine for 3 1/2 hours, at which time one cell read only 1.15 volts (no load) but the other two were at 1.5 volts. After 10 minutes rest all three cells read 1.5 volts and I got 15 minutes more of solid pulsing before the same previously low battery went low again.
My "educated" guess is that pulsed flights of several minutes each could probably go on for at least four hours of total flight time- for most of us that would amount to a whole season! Note: I replaced the low cell with a new one and got another hour of solid pulsing before one of the other "good" cells got low. The other "good" cell was still at 1.43 volts after 4 1/2 hours of steady pulsing. Though not cheap, the use of 357 cells is a good idea to me. It does away with the hassle of delicate Varta cell charging and the extra voltage (3 x 1.5 volts) provides more power to the actuator.
BUYING CO2 CARTRIDGES IN BULK
The larger 12 Gram Cartridges are available in bags of 50 for about 50 cents each, from the G.O. Club. You can get details and order by credit card through their toll free number 1-8OO-888-3006 (24 hrs 7 days a week).
TWO NEAT LITTLE MODELS
The two three views of originally bigger RC models work great scaled down to half size (simply divide all the dimensions shown by two). The first one is mine- I call it the "5150" which means my 1951 design at 50 percent of the original 46" span. The second one is Fran McElwee's "Robot" which comes out to 30" wingspan.
With C02 and the CETO system mine weighs 2 ounces and flies outdoors with the Brown B 100 motor. With a built up fuselage frame and lighter components it can be made to fly indoors at 1.25 oz., using the Brown A23 motor. The "Robot" would probably come out at 3 oz. with stock stuff, but could easily be built to 2 oz with Fritz' BIRD actuator and a small 3 volt battery.
C02 IS A COMIN'
For those who want to fly at minimum weight, C02 power is the way to go. It's not yet ready for everybody, but Fritz and I are working to change that. Currently there are problems and some tricks of the trade are needed to get the most out of C02; namely the problem of charging the airborne tank. As we expect this problem to be resolved (probably this year) we think C02 will become much more popular. Meanwhile, even with its peculiarities, it's better than anything else of equivalent weight and power. More about this as we make further progress.
MORE ABOUT BATTERIES
A constant on-going effort is checking out all kinds of battery types, sizes, and weights, to determine the optimum setup for differing needs. Mostly the effort is focusing on the smallest and lightest cells. Voltage required by the receiver is a key factor. For example, the CETO receiver doesn't like to operate on less than 3 volts, yet we now have actuators that work at 1 1/2 volts or even less.
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So, because the receiver and actuator can use the same battery, the
focus is on the best 3 volt combination, with the key factor being to not
go below 3 volts under full load. This usually means starting with more
than 3 volts (such as 3 NiCads providing 3.6 volts no load). On the other
hand two Alkaline cells, offering 1.5 volts per cell, lose very little
voltage under load. Much depends upon the internal resistance of the battery--
the more resistance, the more voltage drop under load. NiCads have very
little internal resistance, but they typically give only 1.2 volts per
cell, so it usually takes three of them to deliver at least 3 volts. At
present the best combination seems to be three of the smallest Sanyo cells
available. Three 50 mah Sanyo cells have many advantages over the usual
three Varta cells that come with the CETO set, but are heavier. What we
need are three 30 mah Sanyos. Anybody know a source?
CLOUD 9 R/C NEWSLETTER SEPT., 1996
Hi! Another Double Issue. Time flies by so fast. It has turned out that it is more practical to turn out twice as many pages half as often. That's the current pattern, but we hope to settle down to a more regular routine soon. Meanwhile, there is a lot of material to provide for your consideration.
Here's another round of what we're all about-- the world of subminiature RC. The response to the last newsletter issue was overwhelming- lots of orders for BIRD actuators, Cloud 9 Microbugs, and modification of CETO actuators. One thing I found out quickly is that there is too much work
involved in making the Microbugs and to make the effort worthwhile the price needs to be higher. That in itself may kill the appeal and demand, but life is too short to be spending a lot of time doing repetitious tasks when I'd rather be experimenting with new ideas and challenges.
So, I'm sorry to advise that the Cloud 9 Microbugs now carry a $35 price tag, not because I want to charge more but rather that if I need to make anymore the price will be more comparable to the labor involved. Meanwhile, I recommend Fritz Mueller's BIRD actuator for $30, for as long as they are available (Fritz indicates he'd rather be doing something else, too, so his actuators may not be available much longer).
Finally, on this subject, the cost for modification of CETO actuators has also gone up, to $20, because this also involves more work than was originally estimated. One basic problem with the CETO actuators is that they are not all the same internally- coil sizes and magnets vary, meaning that each modification is a custom affair; not simply a matter of switching magnet assemblies
Regardless, the previous situation of trying to work with stock CETO actuators has been improved for a lot of newsletter subscribers, I believe, who ordered one or more of the options offered in the previous Cloud 9 RC newsletter. And I think the situation will improve further. Even CETO is promising a new and better actuator. And other variations of the Microbug may be forthcoming. There are also conventional type micro-miniature servos on the horizon, operated by new multi-channel micro-miniature receivers.
Meanwhile, progress is being made regarding lighter weight versions of existing CETO type equipment. With lighter receivers, actuators, and batteries coming very soon, it's reasonable to expect that Indoor models of 1 ounce total weight will be possible for most of us; not just the extra talented genius types. In the next newsletter issue I hope to get specific on this. In the meantime, this issue's writings by Fritz Mueller gives an idea of what's developing in this area.
CETO INFO SHEET
Enclosed In this issue is an interesting sheet of drawings provided by George Potensky, designer of the CETO equipment. It may not be easy to follow at first, but with a bit of study (and maybe a magnifying glass?) there are many interesting little details to learn about, such as his rolled paper tube connection between the actuator and the rudder; also details of hinge systems.
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FRITZ' ODDS AND ENDS
Once again Fritz Mueller has provided good information for us. Frankly, I gave up trying to understand electronics when transistors came along, even though-- like many of us-- I was able to use them. But Fritz is able to explain in relatively simple terms what goes on in simple transistor circuits. In doing so he also shows us what may be available to us before long. Thanks, Fritz.
THE '5150' MODEL
In the last newsletter there was a small plan of a half size version of my 1951 model design. It is powered by the Brown B-1OO C02 motor and weighs just over 2 ounces, using the CETO receiver, battery pack, and Fritz Mueller's BIRD actuator. After 6 months of erratic results, usually involving lots of crashes, it is now flying very well. What was wrong? Two things: one was that when I was using the Testor's pulse transmitter, the control stick action was backwards so that I was getting right rudder when I wanted left (!); the other was that a tab I had on the right wing which was bent down to offset the model's tendency to turn right actually made the right turn worse (the drag on the right
side was more powerful than the left aileron effect).
I moved the tab to the left wing, bent it up for a left aileron action. And I held the transmitter upside down so that left stick movement gave left rudder. Very elementary things, and now all is well-the model flies beautifully. While I was at it, I changed transmitters: to both the original CETO push button control and to a similar but much smaller MRC transmitter. In both cases, the model flies in a gentle left circle with no signal and goes nicely to the right when the signal-on button is pushed.
The 5150 model is to be featured in Flying Models magazine in a couple of months. in it I note that the weight can be reduced to about half (one ounce) with less sheet balsa, a smaller battery pack, and the Brown A-23 motor in place of the B-100. This version makes for a slower model more suited to indoor flying. Meanwhile, the 2 ounce + version does fine outdoors in a gentle breeze.
It seems like every time I get in a new order of CETO receivers and actuators, the price is higher. The situation is due to fluctuating import costs, based on the value of the dollar. The increases are
discouraging and putting pressure on us to develop our own U.S. made components. The outlook on these is good, so we hope to be able to offer some better alternatives soon. In the meantime, please be advised that the prices for CETO items on any Cloud 9 RC price list are subject to change if the price list date is over 30 days old.
THE TWIN TURBO
For those who want to do serious outdoor flying, be aware that there is a range problem. With some tricks the range can be increased somewhat to permit flying in a ball-field, but otherwise the Twin Turbo is probably best regarded as an indoor model control system. It's fine for that and it offers a lot of intriguing control possibilities and it definitely is a bargain in regard to cost vs value. In many ways it is a tinkerer's goldmine, which is why you can now get the system through Cloud 9 RC and
even slightly cheaper than the incredibly low magazine advertised price.
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If all you have played with before in the way of very light RC systems is the CETO, you can expand your horizons with the Twin Turbo and have a lot of fun. You get a two stick transmitter and a two channel receiver, ready to operate upon battery installation, plus two electric motors!
COUPLE OF CUTIES FROM KEN WILLARD
Bill Poytbress Saugerties, NY) sent drawings of two small RC models by the late Ken Willard. An article about these models was apparently published in Model Airplane News (don't know when). Then, sometime later, the designs were shown in a British book called the Aeromodeller Annual (don't know what year), The drawings reproduced in this newsletter are from the book.
The models are really cute, intended for Indoor flying, and seem ideal for our kind of activity, with one exception: they show the Cox glow engine installed- can you imagine the noise indoors?!! Also, glow fuel indoors would normally not be allowed.
Otherwise, the models would be fine, with CETO type RC systems and, with C02 power, could be built to a total weight of less than two ounces. The drawings are apparently about quarter-scale (1/4 original size) so that the wingspan is about 21 1/2". Here are some of the notes from the article in the book: "The model is adjusted to fly in a 30 foot circle to the left. By pressing the button on the transmitter once, right rudder pulls the airplane slowly into straight flight and then into a gradual right turn. It isn't too hard to come up with a few refinements to the design and come up with a really attractive indoor RC job which you can fly in the local high school gymnasium. For example, make the boom hollow and run the torque rod through it-- maybe close in the cabin area with a light shell of balsa." Note: with Fritz Mueller's ultra light actuator (a gram or less) built into the tail, a hollow boom is not necessary. The article goes on: "The open framework, single surface wing and lightweight radio are virtually mandatory since slow flight is a must, and that means ultra light wing loading."
NEAT LITTLE BATTERY
If you're seeking minimum weight and size models, you might try using the 3 volt Lithium CR 1/3N battery sold by Radio Shack. It's rated at 160 mah, which means it's good for many hours of operation in a CBTO RC system. Size is only 7/16" dia. x 3/8" long, weight is 3 grams. It's not
cheap, but considering how long it will run the CETO system the cost of $4.79 is nor unreasonable. The R-S part # is 23-265. Big advantage, besides size and weight, is that it is always ready to go; no charging required. I have flown this battery in my 1.5 ounce "Lanzo Stick" (27" wingspan) and have operated it for long periods on the bench. I probably now have more than an hour of operation with it, using Fritz Mueller's BIRD actuator, with no signs of slowing down. Needs no battery box-- simply solder wires directly to the battery (with or without a CETO plug) and tape it to the model.
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ALKALINE ALTERNATIVE TO THE 'CETO' VARTA CELLS
Radio Shack sells the Duracell 6 volt PX28A battery for $ 3.49. You can split open the thin metal shell of this battery, along the seam, and out pop four neat little A76 Alkaline button cells. Three of these at 1.5 volts each provide a 4.5V pack for the CETO radio. They simply snap into the CETO battery box-- no wiring or soldering involved. The extra voltage provides more power for the standard CETO actuator. The total of four cells for less than a dollar each is an excellent buy. The alkalines work right down to one volt each cell, so even though they are not rechargeable they will last a very long time before needing to be replaced; probably several hours of flight time.
NEW CO2 COMPONENTS
Fritz Mueller, working in conjunction with Bill Brown (Mr. C02), now offers a line of items to improve and simplify C02 charging, especially for very small models. The basis is a 1mm Filler Tip and Charger Check Valve. This much smaller size requires much less manual pressure to mate the charger to the filler tip in the model. Thus, typically, much less C02 is lost during the model charging process-- just a simply "blip" and the model tank fills easily.
Fritz has also made these components for both the Brown and Gasparin C02 motors so that separate fittings for each system are no longer needed. Fritz is also making these available at lower than normal prices, to help newcomers and those with the old filler systems to switch to the 1 mm fittings at minimum cost. At Cloud 9 we're now using the 1mm fittings exclusively-- they're great!
Order directly from: Fritz Mueller 4117 Searcy St Columbus, GA 31907
1 mm Charger which uses 12 gram C02 cartridges ($30 retail value)
1 mm Filler Tip to replace 2 mm Tip on Brown C02 motors.
1 mm Check Valve to replace 2 mm Valve
1mm Filler Tip to replace 2 mm Tip on GM-63, with 0-ring and Ball
1mm Filler Tip to replace 2 mm Tip on GM-I 20, no 0-ring or ball
Brass filler base to solder onto other feed lines
THE INCREDIBLE 'TWIN TURBO'....................
This unique 2 channel RC set is far more than the "toy" image the ads for it make it appear to be. Although incredibly low in price, it has very high tech circuitry which provides eight control options to drive its two little electric motor ducted fans: both forward thrust, both rear thrust, left forward, right forward, left rearward, right rearward, left forward and right rearward, right forward and left rearward; note that simultaneous controls are involved, in accordance with the transmitter's dual stick positions. The ducted fans and the control system are ideal for controlling a blimp or balloon, also fan driven cars, boats, even rafts! Airplanes too may also be flown with the system.
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But the Twin Turbo system offers much more; an experimenter's delight. Instead of driving the two ducted fan motors, it can be used with a conventional prop powered model plane to operate magnetic actuators to simultaneously or individually provide four control options; such as right, left, up or down. In its original form, the whole airborne ducted fan system weighs only two ounces. But take out the receiver from the fan enclosure and hook it up to little magnetic actuators (such as come with the CETO RC set, or others available from Cloud 9 RC) and a complete 2 channel airborne RC system is possible weighing from 1/2 to 1 ounce, depending upon battery and actuator choices!
The little motors that drive the Twin Turbo ducted fans are fine for driving 'normal' props in a conventional little electric powered model. Between these, the 2 channel receiver, and the two-stick two-channel transmitter, the Twin Turbo RC system is the biggest bargain in RC (and it's now available from Cloud 9 RC).
Range is limited so that in stock form indoor flying is the most practical use of the system. But with a couple of simple antenna modifications (merely adding about a 24" length of thin flexible wire to the ground side of the transmitter and receiver circuit boards, to provide a dipole effect), enough extra range for flying in calm weather at a local ball field is obtainable, with minimal weight addition to the airborne system.
In summary, the Twin Turbo system is a lot of fun and highly educational in terms of offering new ideas and challenges. It does much more than other very lightweight single channel systems which cost a great deal more. At Cloud 9 we're working on some accessories to enhance the system further; such as a center off magnetic actuator that provides full right or left (or up and down) control positions.
Simplest operation: take the stock units from the box, install batteries, scotch tape the receiver/fan unit to the sheet styrofoam box cover, float it in your bathtub or swimming pool, and drive it with the transmitter, all in less than 15 minutes!
CLOUD 9 R/C NEWSLETTER DECEMBER 1996
Here's another double issue. We've been counting 4 pages as an issue of the newsletter, but that doesn't provide enough space for all the news on hand so we're doubling that. Eight pages are likely to become the norm from now on if we keep accumulating so much material. For 1997 you can assume there will be 16 pages per issue and at least four issues for the year--that's more total pages than six previous issues provided.
Regardless, this is to advise that if you wish to continue receiving this newsletter you will need to renew your subscription soon, preferably by the end of December 1996. To renew, you need to send $10. Please do so now. That's more than the previous subscription fee, but costs--particularly printing--have gone up considerably. Incidentally, the newsletter now has almost 200 subscribers--the list grows by about ten a week!
If your address label for this issue has a pink line at the bottom, you don't have to renew--you are already recorded as a 1997 subscriber.
TWO BIG NEWS ITEMS:
One is that the Twin Turbo RC system is now flying in a 1-1/2 ounce, 30" span model, with a simple modification that makes this system practical for everyone. The other is that there is now an equivalent to the CETO RC system at only 3 grams instead of 14! Both these developments will be detailed further in the next issue, beyond what we're able to tell you in this one.
TWIN TURBO BREAKTHROUGH:
Until now we've thought of the Twin Turbo RC system as something to fly blimps or balloons with, or to operate model cars or boats; more like a toy thing than something practical for model planes. For planes it has had another role, to provide two channels of control (such as for a Rudder and Elevator) in a model powered by something other than the T-T ducted fans. While the relatively low thrust ducted fans worked okay as a controllable power source for a blimp or other form of helium lifted vehicle, the use of these fans to power a more or less conventional model airplane has largely been ignored, in the belief that not enough power would be available,
But what has now happened is that the Twin Turbo power system, only slightly modified, has been flying a model plane very well. This development means that everyone will shortly be able to enjoy this system, by following the plans and instructions soon to be published in one of the major model magazines. We can't tell more about this until after Dec.31, although the information may leak out before then, since we agreed to not give specifics until Jan. 1.
All we can say for now is that a very nice, relatively conventional, model design by one of our subscribers has been flown many times outdoors, in a space about half the size of a football field, with excellent power and control. You will be hearing much more about this very soon! Why not get ready to duplicate this achievement by ordering your own Twin-Turbo RC system now?
THE THREE GRAM R/C SYSTEM:
It's true--we've seen it and tested it: an airborne RC system equivalent to the 14 gram (1/2 ounce) CETO system, but weighing only about 1/5 as much--only 3 grams (just barely over 1/8 ounce).
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Like the CETO, the receiver is 27 MHz, super-regen,
with a magnetic actuator. But it operates on only 1.2V (ideal for a single
subminiature Alkaline cell). It's perfect for Peanut size (13" wingspan
or less) models. If your model can carry a copper penny, it can fly with
this new system! It's only 1/4" x 3/8" in cross-section, x 1-1/4" long!
The system is complete in a single unit; including the receiver, battery,
and actuator. Simply link an appropriate push-pull rod from the actuator
to your rudder and it is ready to go. Connect the battery; operate any
of the transmitters that will operate a CETO system and the rudder follows
just like it would if attached to a CETO actuator. This fantastic advance
in micro-miniaturization is expected to be available from Cloud 9 RC early
in 1997. Cost is being negotiated and we hope it will be only half again
as much as that for the CETO airborne system; about what you would pay
for the complete CETO system but in this case no transmitter would be provided.
Credit Fritz Mueller with being instrumental in this product's development and availability--somebody else will be making the units but Fritz was a key figure in getting this from the idea stage to production. Thanks once more, Fritz, for another major contribution to micro-miniature RC.
This newsletter is becoming the principal product of Cloud 9 RC. The subscription list keeps growing, from about 40 in mid-95 to almost 200 near the end of '96. It has gotten bigger (more pages) and--many readers tell us--more interesting. So far, no scarcity of info. Just like in the 50's, when new developments were popping up almost every week, we're seeing a similar scene regarding micro-miniature RC; a steady stream of progress involving ever smaller planes and equipment. I have no problem foreseeing the time when we will be able to fly little RC planes inside, at home.
The field has proliferated in two somewhat different but related directions: Electric power and C02. Rubber, Compressed Air, Glow, and Diesel power plants are also in the picture, but with more problems than the others. C02 seems to be the most practical where lightest weight is desired, but electric power is not far behind.
Until now the CETO RC system has been the most popular, using various actuators, in models weighing from 1 to 3 ounces. Soon however, with other systems, we should be seeing more of the one ounce or less models, flying in school gyms. What we're talking about here is not super-special stuff by exceptional people, but off-the-shelf stuff flown by less skilled modelers.
At the same time, we can expect to see many more modelers flying little stuff outdoors, using equipment a little bigger and heavier, in models weighing about 8 ounces and using regular type but much smaller real servos; with 3 and 4 controls. These models will be very small equivalents of what most R/C'ers fly now; crystal controlled and relatively narrow-band so that several can be flown at the same time.
All this is on the immediate horizon, with 1997 to be a big year in making it happen.
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The CETO and similar (Albin type) receivers are single channel. Some might even call them Half-Channel because a transmitter signal produces control action in only one direction (unless a pulsing signal system is used to achieve controlled movement in two directions-- right and left--or even proportional control to obtain effective control positions in between full right and left.
But a lot of people prefer to operate with two separate channels. It can be done with a combination of the Twin-Turbo system, using magnetic actuators in place of the ducted fan motors. The Twin-Turbo system can drive two CETO type actuators (for Rudder and Elevator, for example) although, for now, not proportionally--the latter can be done, but with more complicated circuitry.
To use the magnetic type actuators with the Twin-Turbo system, it's necessary to eliminate the magnetic or spring biasing which holds the actuator arm over to one side with no signal. For CETO actuators the simplest way is to carefully remove (with a razor or pliers) the small bias magnet (little red cube) glued to the side of the actuator body. The actuator arm is then free-floating with signal off Instead of the bias to one side, a very light spring is used to hold the Rudder (or Elevator) in the Neutral position.
Then, depending upon which position the transmitter stick is moved to, current will flow through the actuator coil in one direction, resulting in control movement to one extreme. When the stick is moved to the opposite position, current from the receiver flows through the actuator coil in the opposite direction and the control is moved to the opposite extreme. Thus one control stick obtains three control positions from one actuator: Neutral (signal off--stick centered), Right Rudder, Left Rudder. Likewise, the other stick obtains three positions from the other actuator: Neutral, Up, Down.
Note: To substitute actuators for the Twin-Turbo motors, the two wires from each motor must be unsoldered then re-soldered to the two wires coming from each actuator. To get the polarity right for desired direction of control motion, it may be necessary to reverse the wiring to either or both of the actuators. The trickiest part of this system is to get the control centering just right--a very light spring (perhaps in the hinge itself) to hold the control surface in Neutral, with minimum force opposing the control surface movement.
INCREASED RANGE FOR THE TWIN TURBO SYSTEM:
Simply let the receiver antenna hang down. Range improves with altitude (the transmitter signal radiation pattern is like an inverted cone--wider up high than on the ground). The receiver antenna hanging vertically works better to receive the transmitted signal. This is most noticeable when flying outdoors, but it helps during indoor flying too.
In this issue are plans and information from Fritz Mueller concerning his very neat little "Radox" C02 model design. It is a beautiful flying model and very simple to build. A brilliant feature is that the fuselage sides are parallel, which means that all the cross braces are the same size (13/16"), so that a whole bunch of them can be cut at once. The model uses one of the "BIRD" actuators, which we still have in stock, and can use the Albin or CETO receivers.
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DAVE'S BABY CANNON SERVO:
Previewing what we can expect to see before long is a sketch page by Dave Robelen (Farmville, VA) showing his reworked and stripped version of the Cannon Ultra servo. Servos similar to this are being developed by several R/C manufacturers. Dave's weighs only 6 grams (or less, if the Cannon plug and cable is not used). All parts are listed separately in the Cannon catalog, or you can do like Dave did and rework an Ultra servo. Exception: the feedback pot (.75 watt, 5,000 ohms, wire-wound) will need to be gotten elsewhere--the wire-wound linear pot gives double the amount of travel of a film pot (resistance element is longer). Note: the drawing is twice the size of the actual servo.
MAC'S CO2 STUFF:
Enclosed are a couple of pages of C02 info and drawings by Mac McJunkin (Riverside, CA), done back in 1990, as part of the Flightmasters' club newsletter called "Scale News and Views". Mac has been a C02 expert for many years and he has contributed greatly to the "know-how" of operating C02 motors, just as Fritz Mueller has. We hope you find the information useful.
BEST BATTERY BUY:
There's an incredible value in tiny batteries, available all over the country. These are 1.5-volt Alkaline hearing aid cells that are 1/8" thick x 3/8" diameter. Operating the CETO receiver and Mueller 'BIRD' actuator, two of them in series for 3 volts pulsed a rudder on and off for 2 hours and 15 minutes! Without pulsing, moving the rudder only about once a second or so, the operating time was double that.
Not only are these batteries good electrically, there are very light and small, but they are also amazingly cheap. Eight of them are enclosed in a 12-volt battery case--simply peel open the case and the eight cells spill out, ready to use. Radio Shack sells them as their part no. 23-154, for a package of two of the 12V batteries, for $5.49--that's 16 cells for about 35 cents each! But you may be able to get them even cheaper'. in some Safeway supermarkets and other stores the 12-volt batteries have been found as singles at anywhere from 99 cents to $1.99! Look for the Duracell N21. This is probably the single best buy in the micro-miniature RC field.
The new 3 gram RC unit described earlier in this newsletter uses only one of these cells, the CETO uses 2 or 3 (depending upon whether you want 3 or 4-1/2 volts. For any use of 50 milliamps or less these cells fine to use. At the low price you can afford to toss them out when they die.
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