President Ron Brownell  EMAIL Vice President John Weales EMAIL Secretary Rich Howe Treasurer John Alford NEXT MEETING MARCH 1, 1998 *** GLEN STEWART PARK, OSHAWA ***     PRESIDENT'S COLUMN

I must open with the comment of how much I enjoyed last months guest speaker, on the merits of using Iron on Coverings. Peter did an excellent job with his presentation and I am looking foreward to using some of the tips I picked up from his Seminar. This month we will have as our Guest Speaker our South East Zone Director, who will be able to bring us up to date on all the things that are taking place as far as M.A.A.C. is concerned.
January has been an extremely busy month for me, with the big Ice Storm which has hit Eastern Ontario my main concern. As Most of my Family live in that area of Ontario, I was busy begging or borrowing generators to try and keep them warm until the power is restored. I wish to use this space to say Thank you to Winnie and Ed for helping us when we needed it the most.
I sure hope the rest of the winter will be very uneventful so I can return to building my Extra 300. Don't forget the Joint Club Auction is Sunday February 1st, the same day as the meeting, so dig out all those unused items and turn them into cash. See you then
 

...Ron.... Club Executive President---EMAIL- Ron Brownell Vice President ---EMAIL-John Weales Treasurer--- John Alford Secretary--- Rich Howe Field Chairman--- Al Cameron/Gord Simpson C.F.I--- Winnie Ambruch Bulletin Editor--- EMAIL-Ian Smith Scamp Racing--- Vic Ibanez/Rich Howe Waterbirds Chairman--- John Weales/Jim Johnson Wed Nite Float Fly--- Open Fun Fly Chairman--- Wes McLaren/Phil Peliquin Noise Control--- Vic Ibanez Public Relations--- Open Auditor--- Jim Moss Auditor--- Keith Kettle Beauty Contest--- Wes Mclaren/John Hass Video--- Vic Ibanez   Upcoming Events   HELP JOHN INFORMATION WANTED FOR MY WEB PAGE

I have been working on a INTERNET WEB PAGE for the last 2 month's and was wondering if anyone has something they would like to post on it. It, can be tips, articles for sale, kit reviews etc. My page at the moment is getting around 20 hits a day and is linked to may other sites on the web. I am looking for some unique stuff to attract visitors and keep it fresh. I already have some information on it for designing, some tips and hints and pictures. If you want to preview my site the Url address is:

http://webhome.idirect.com/~weales

You can contact me at  weales@hotmail.com

Thanks
John Weales Sunday Feb 1 Joint Club Auction Sunday Feb 1 Club Meeting Guest Fred Messacar South East Zone Director Sunday April 5 Club Meeting and Beauty Contest Fri-Sun April 3-5 Toledo Wednesday May 27 Float Flying Begins Monday June 1 Scamp Flying Begins Fri-Sun Nov 6-8 The Hobby Show Buy & Sell Balsa USA NorthStar 40 Still in the Box $ 75.00 CAll Peter Breen 905-697-0586   Editor's Note: If you have anything you wish to buy or sell and you want it in our newsletter, fax Ian at  (905) 432-1260 Fax   E-Mail iansmith@Durham.Net   Editors Comments Hope you building projects are all going well. I'm building a Seamaster 40 ,Seagulls watch out. I've heard that a couple of fun flys are in the works so stayed tuned for more information. See you all Sunday......... Ian       Flying & Safety Rules (1995)

1. Club members may go onto the field at any time as flyers, helpers, or observers. They may also take guests onto the field for observation purposes. All others shall remain off the field. Caution and consideration must be exercised at all times.
2. Guests of the Club may fly at the field, providing they show proof of M.A.A.C. insurance or equivalent, and are accompanied by a Club member. Members will be responsible for their guests. (Limit of 2 visits per season per guest). Exception is the weekly float fly where guests are not permitted. (re: Darlington Provincial Park Rules)
3. No one shall attempt to fly unassisted until they have demonstrated to an instructor their ability to take off or hand-launch, fly, and land safely on their own.
4. Frequency control shall be used at all times regardless of the number of flyers.
5. Transmitters shall display either the appropriate channel numbers or the appropriate colored frequency ribbons, or both of the above. Antennas shall be fully extended before starting engines and collapsed at the completion of the flight.
6. All flying will cease during Field Maintenance.
7. Prolonged engine running must be done in the designated area. Frequency control is to be exercised if a transmitter is required. The frequency shall not be retained longer than 15 minutes, if another flyer is waiting to use it.
8. Airplanes shall not be flown directly at, or taxied into the pit area, or flown in such a manner that monopolizes the air space directly over the field.
9. Flyers shall stand in the designated area while maneuvering their aircraft.
EXCEPTIONS ARE:
(a) Airplanes that cannot be taxied due to wind or other conditions.
(b) Airplanes that flyers may wish to stand behind for take off purposes.
(c) Airplanes that must be hand launched.
10. Garbage, refuse, broken props and crash debris shall be placed in the containers provided. Picnic tables, garbage contain- ers and other non-flying items shall not be placed on the flying field.
11. Exhaust shall be directed away from all other flyer's equipment.
12. No aircraft shall exceed the noise level of 91 DBA, measured at 7 meters, 90 degrees to and downwind from the muffler side of the aircraft while the aircraft is is sitting on the wooden noise measurement stand.
13. It is recommended that Club members carry a FIRST AID KIT.
14. Flyers shall observe the M.A.A.C. height restriction of 400 feet and avoid ANY CONFLICT with full size aircraft.
15. Repeated infractions of the Club Field and Safety Rules will be subject to
disciplinary action, at the discretion of the Executive.
16. No flying before 9 A.M. on ANY given day.
17. No flying of the west side of the pit area, and too far north toward Taunton Rd. (This is where our neighbors live.)
18. It is recommended that you not fly alone, for safety reasons.
19. Changes to the above rules may be made by the Executive as required.
 

  OSHAWA RADIO CONTROL CLUB WEEKLY FLOAT FLYING DARLINGTON PROVINCIAL PARK EVERY WEDNESDAY MAY 27 AUG 26 5:30 PM DUSK INFORMATION AVAILABLE FROM CLUBS EMAIL GUIDE FOR FLOAT FLYING 1) Air Craft must float (`UPRIGHT'). 2) Four Aircraft in the air at one time. 3) Flight line will be designated with'Pilot"signs (spaced approx. 25 ft. apart). 4) Pin board must be used. Four pins on the board only. 5) Taxiing aircraft permitted inside flag markers. Takeoff, flying and landings outside of flag markers. 6) All Flyers must be members or associated members with M.A.A.C. due to commitment to park officials. Guest Fliers are not permitted. 7) Life jackets are recommended to be worn in club boat.     PYLON RACING EVERY MONDAY EVENING JUNE 1 THRU AUG. 31 ORONO FLYING SITE RACES START 6 PM QUALIFICATIONS: Must be Sig Scamp: No substituting kit materials. Scratch built must be duplicate of kit size, materials foam wing, etc. OS 15 or OS 15 FP engines only. Fuel will be supplied Byron 10% nitro 20% oil Race will be 15 laps. Points for finishing heat. Points accumulated over 13 evenings. Awards for I 4 at end of season. Accidents do happen, be prepared Bring your own bag. Cost $2.00/night/pilot For more information EMAIL CLUB SCAMP RACING FREQUENCIES IN USE 080 ED TURESKI 14 JOHN WEALES 15 JOHN ALFORD 15 JASON BAGNELL 18 MIKE SHARECK 22 RALPH TRAUZZI 36 JIM MOSS 38 BOB GARDNER 42 RICH HOWE 44 WINNIE AMBRUCH 52 VIC IBANEZ 54 RON BROWNELL 56 PHIL HENSTOCK  

Parallel Operation Reliability & More Flight Time

The use of redundant parallel fight packs (packs may be of different capacity but MUST be of an equal number of cells) is an excellent way to increase the available flight time and significantly improve the reliability of the on power system. The simplest means is to run two complete wiring harness, switches and charge jacks from each pack and plug one into the normal battery port and the other into an extra channel on the receiver. No diodes or isolation is required (see below). This is simpler and more reliable than some of the complex battery backup systems being offered on the market. Whether you are using 4 or 5 cells is your option, remembering that a 5 cell pack will provide more power to the servos but at the same time discharge faster giving you less flight time. Parallel charging of NiCds is not recommended due to the tendency of the cells to have the voltage drop off after they reach full charge. Should one pack have a slightly different capacity than the other then it will reach full charge sooner and the voltage will start to drop off allowing more current to flow into this pack. The other pack may not then reach a full state of charge. Repeated charge/discharge cycles under this parallel arrangement causes additional charge unbalance. While you may experiment and find that you get what appears to be both packs charged you will eventually run into problems with this arrangement. As an extreme, take the case of two packs, one having 250 mAh capacity and one having 600. The smaller capacity pack will reach full charge much sooner assuming that there is at least an equal "sharing" of charge current. As it peaks and the voltage declines slightly due to the heating of the battery as the oxygen is recombined it will begin to take more and more current to maintain a voltage equal to the as yet uncharged pack and the voltage tries to drop further and demands even more current to keep it up. This pack will then be taking nearly all the charge current leaving the larger pack woefully short during what would be perceived as a normal charge time like 16 hours. Many pseudo battery "experts" put forth the argument that plugging two battery packs into the same receiver with out blocking diodes is NOT a good thing, claiming that his creates a host of problems and the two packs will end up fighting each other or "cross charging".
These concerns show a lack in the understanding of the charge and discharge potentials involved in NiCd cells. One pack cannot charge the another (equal number of cells) as the discharge voltage of a pack can never be as high as the voltage required to charge the other pack. For the doubters here is an experiment: completely discharged one pack to 4.0 volts and then connected to a fully charged pack having an equal number of cells. There will be less than transfer of charge in a 24 hour period. Since shorts rarely occur in fully charged packs the risk of one pack "dumping" into one with a shorted cell are insignificant. A simple ESE preflight test would detect a pack with a shorted cell.
While it is a fact that the typical failure mode of a battery is for a cell to fail shorted there are some subtleties here that escape many people. First, one of the major causes of "battery" failure has nothing to do with the batteries themselves but rather with a switch or connector in the battery circuit. The dual redundancy concept is to protect against the failure having the highest probability that being the circuit path from the battery to the power buss in the receiver. Adding more components to this path, like regulators and/or diodes isn't going to help the matter but rather adds to the probability
of failure.
Perhaps the following discussion on the nature of shorts will better help the modeler understand.
While it is agreed that shorts are the failure mode in NiCds batteries one has to look further into the "when" of the failure. A short develops in a NiCd when conductive particulate bridge the separator or the separator itself deteriorates to the point where it allows the positive and negative plates to touch. Rarely does the short occur all at once but rather building up a very small conductance path termed "soft shorts". In a charged cell the energy in the cell will blow away any short as it tries to develop. You've heard about zapping'' cells. The cell actually zaps itself before the short can develop. Only in cases of severe overcharge at high rates can the separator melt down to the point where the plates contact each other (hard short). In this case the energy in the cell then dumps and we have what is referred to as a hot steamer, the electrolyte boils, nylon in the separator melts down and is forced by the steam through the vent. On some occasions the vent is clogged by the molten nylon separator and becomes inoperative causing the cell to rapidly disassemble. So under normal circumstances a cell maintained at some state of charge is much less likely to short than a cell that is completely discharged. It should be noted however that the self discharge increases rapidly in cells where there is a short building (high resistance soft short) due to separator deterioration and/or cadmium migration. One other shorting mechanism is a manufacturing defect where the positive or negative collector tab bridges the opposite plate. These usually fall out before the cells are shipped or assembled into batteries. Preflight procedure should involve checking each battery separately. First check each with ESV through charge jack. you should get nearly identical readings, then switch one on, check controls, switch off and then switch on the other battery, check controls again, then turn both systems on and fly with confidence.
Summary: Diodes are not required. Packs must be of the same number of cells. Packs may be of different capacities. Individual charge jacks must be provided for each pack  and not interconnected). Total capacity available will be the sum of the individual capacities. Specialized chargers are not required since standard packs (600-800 mAh AA packs) can be charged employing regular system wall chargers (1200 to 1600 mAh should cover most giant size projects).
Red Scholefield AMA 951 redscho@gnv.fdt.net DON'T FORGET TO COME BACK NEXT MONTH