Comments on Hitec 2.4GHz & Wiring Twin BEC From Gary Gullikson ggullikson@socal.rr.com      I just got my Hitec 2.4GHz module and first Optima 6 receiver for use with my Eclipse 7 transmitter. Haven't bound and tried it yet. I cannot believe that the Hitec USA team did not proofread and make the instructions more understandable. I wonder if the Asian language versions are any better. Maybe the factory folks don't deign to talk to the US folks who must explain their terrible instruction sheets.      Actually the Hitec Optima 6 receiver is smaller than I thought and the Boda antenna is too. The Optima 6 has end type servo connections which is better than standard on top plug-ins. My fuselages never look "too pretty to cover".      Pat's design (SR-10) looks a little bloated versus the 1:1 Reliant but it should fly scale-like. Your bipe conversion is looking great. Enjoy, but watch the other guy. Simultaneous twin brushless motor LVC      I have been flying a GWS ME-262 with two 2028 3900K brushless motors. If I fly too long or have to go around another time before landing, one motor may shut down before the other due to one speed control's LVC circuit acting before the other. When this happens the other speed control sees sufficient voltage and keeps running full tilt. This can result in a crash due to asymmetric thrust if I don't chop throttle fast enough and regain control for a dead stick landing.      I found out that Dimension Engineering's "Smart BEC" has it's own LVC circuit that will over-ride the two speed control's LVC circuits if they are both speed controls are set for NiMH cutoff.      I haven't had a chance to try this yet but attached is my crude diagram based on advice from Dimension Engineering and Castle Creations and the guru's on RCGroups. If this works it would also apply to twin motor twin speed control propeller models such as B-25's, etc. Probably could be expanded to 4 motors, etc. Maybe Keith Shaw or others might have some thoughts about this. (Note: Unfortunately, Gary's diagram didn't resize very well, and it is not reproduced here. Please send him email if you'd like his diagram. KM)      I am a true believer in using switching-type BECs when using amp hungry 2.4GHz receivers and more than 3 servos I think that the hobby industry has been reticent and slow in informing users about the need for using switching type BECs.      Keep up the good work on Ampeer. Gary Gullikson, "E-Challenged" Return to "What's In This Issue" More Mid-Am Thanks & Other Related Topics Ken,      I had a great time again at the Mid-America and the weather was fantastic. I flew my foamies; 2 birds and a wing. The real birds were chasing them all the time, so they may look like birds after all. I mentioned this in a post at the dirty birdy thread, (www.rcgroups.com/forums/showthread.php?t=1020550&page=11) together with some photos.      Thanks for your terrific work running the event. You did a great job, as usual even persuading the gods of the air to bring us great weather. Phil Alvirez, Windsor, Ont., Canada      Thanks Ken. It's sad the Mid-Am only comes once a year! Take care, Don Belfort Ken,      Bob Livin and I had a great time at the Mid-Am. We did no damage to our models, which for a couple of old geezers is not bad.      This photo of Bob Livin's Nomad was taken at the Mid-Am.      Here is a little about the Thermaleer that you used as the Mid-Am teaser photo in the August Ampeer. W.S.: 76" Wing area: 720 sq. in. Designer: Daniel Veronica Published 5/40 Air Trails Kit: None Builder: Robert Livin Battery: 5 A 123 cells (DeWalt Cells) Motor: Aveox Sport 40 direct drive Fuselage: Planked construction. The only straight line is the centerline :-)      All of the old timers have too much dihedral so Bob took a bunch out and it turned out the plane was difficult to control. So he bit the bullet and took the turtle deck over the wing apart and increased the dihedral. It now flies fine. The covering is a Polycarbonate Coated Ripstop Polyester. It is sold by Hang em'High. ecom.citystar.com/hang-em-high/ushop/index.cgi      I already sent you a photo of Bob's latest, the Nomad, which was designed by the late Chuck Hollinger.      He also designed the rubber powered Cruiser. From an AMA history document submitted to the AMA in 1997 by Hank Cole.      He kitted a rubber cabin model called the Cruiser, which was recently built by some modelers in Iowa. He built a beautiful, pod and boom, C-gas model called the Nomad, which he flew at the Nats and plans were published in Air Trails in the early 1940s. The design is currently being flown in Radio Control electric. The "some modelers" in must have referred to Paul McIlrath and me. I saw Paul's model fly and had to have one. As the plans were in Air Trails (about 1946) it was easy to get a copy. Plenny Bates Return to "What's In This Issue" A Strange "A123" 2300mAh Occurrence By Ken Myers      I took the Super Stearman and the Flite 40 (www.rcgroups.com/forums/showthread.php?t=735972) to the flying field on the evening of August 12. I "normally" charge my "A123" 2300mAh batteries before leaving the field after a flying session, so they are stored charged. To double check that I follow my normal procedure with a pack, I put them on charge on my CellPro 10S at the field before flying and take a peek at the numbers. The CellPro 10S reported a cell count error on the Flite 40's 6S "A123" 2300 pack. It would not charge the pack. I kept trying to get the pack to charge so that I could see the numbers. I thought that the 'hacked' 7-pin balance plug was not working correctly. The 88-deg+ heat and sun caused me great frustration with repeated tries. Paul let me borrow his AstroFlight 109 with the "A123" mod in it. It reported that it was trying to charge a 7-cell pack. I stopped the charge and we used Paul's voltmeter and measured over 26 volts with no load. What? No way! A fully charged 6S "A123" 2300mAh pack should only be about 22 volts.      I ran the pack for a couple of 20 second bursts on the ground and then flew it for its normal six-minute flight. When I landed, I put it on charge on the CellPro 10S and it took a normal charge. Later I flew the plane once again for a 'normal' flight.      For its entire life, the pack has only been charged with the CellPro 10S. The plane with the pack in it had not been flown since some time in June and had been sitting in my 67-deg F basement since its last charge in June.      I really have no reasonable explanation for what happened and why the pack was "over-volted". The only thing that I can think of was that the 20-deg F temperature difference might have had something to do with it, but that doesn't make sense to me.      The other possibility was that I somehow managed to charge the pack as a Li-Poly before storing it. I really doubt that I could have done that as the CellPro 10S would not have worked on the Li-Poly setting, as the cell count would have been wrong for the voltage and number of cells. I really doubt that I did that as I have my CellPro 10S set up to do "A123" 2300mAh cells at either 2.4 amps or 10 amps and for my "storage" charge I use the A123 10 amp setup to do it as quickly as possible before leaving the flying field.      If any of you readers have any other ideas of what might have caused this unusual happening, I'd be interested in hearing from you. Return to "What's In This Issue" Bob Kopski's BDM & Some "A123" Info From Richard Golding rngolding@aol.com Hi Ken,      Came across your excellent Ampeer Magazine on the net and was intrigued by Bob Kopski's article describing his Battery Discharge Monitor and would like to build one (I'm a retired Electronics Engineer). Could you please arrange to have build details emailed to me as offered in the text - I couldn't find Bob's email address. I have been tinkering with a similar project and have been using a Hall Effect current sensor. Oops, sorry about that! Bob can be reached at kopskib@gmail.com      I'm also a fan of A123 batteries and have several planes powered by them - some of the packs have been in use for 3 years and are still going strong.      I have attached pictures of my latest plane. It's supplied as a kit (balsa sheet etc) by SLEC here in the UK - it used to be a Precedent Fun Fly (Wingspan is 52") before SLEC kitted it. The plane was intended for IC, but we don't want to do that do we? The A123 battery pack fits nicely in the fuel tank compartment.      The motor is a Turnigy SK4250-650, powered by a 6S1P A123 pack, which produces 575 Watts @ WOT with a 12 x 6 EMP prop. (9660 rpm @ 17.63V and 32.6A). It gives me about 5>6 minutes of 'spirited' flying. Incidentally, using the drill press method, the measured Kv of the SK4250-650 was 603 rpm/V, not 650 as claimed on the data sheet.      Keep up the good work. Best wishes, Richard Golding G3VZG Return to "What's In This Issue" A Problem with FMAdirect Adapter Boards Discovered Ken Myers      Joe Hass of the Skymasters' RC club contacted me about a problem that he had had with an FMAdirect Adapter Board for the CellPro 10S. His charger had stopped working, so he sent it in to FMAdirect for repair. They contacted him and asked how/why the traces on the PCB adapter board became charred. He had not noticed it and had no idea.      Looking closely at the PCB of the adapter we can see that the connector pins, that go through the PCB and allow the connectors to be soldered to the traces, have sharp points, created by the solder, on them that can pierce the heat shrink covering if the adapter becomes compressed somehow. If the pins have penetrated the heat shrink and contact something metal, say a part on an automobile body when charging in an open car engine compartment, they can short.      Regarding the piercing, Joe said, "I think that the piercing can take place just from heat and use."      On one of the boards that I own, one pin of one connector has penetrated the heat shrink. To the best of my knowledge, the adapter has never been compressed. I do all of my charging in my planes, as I use "A123" 2300mAh packs in all of the planes that I fly on a regular basis, and my adapters are generally "hanging" in midair when I'm charging with my CellPro 10S.      The way to avoid the pins shorting is to place some kind of sticky-backed padded tape on the back of the adapter over the heat shrink. I used some Velcro that I had more of than its mate. There was no particular reason to use the Velcro except that is what I had on hand.      I am not familiar with other companies' similar boards, but I would suspect that they have a similar problem as they are all made, most likely, in a similar fashion.      Joe let me know that he had received word from Howard Matos of FMAdirect technical support that they had contacted their manufacturer in Singapore and they are now flush cutting the pins on the adapters. Howard noted that this would prevent them from poking through the shrink.      Howard also noted that the diodes were blown due to a short circuit on the charger and that the diodes blow to prevent major damage from happening to the charger.      Joe believes that the short circuit that Howard spoke of was cause by the balance board design, not an end user problem.      The bottom line was that Joe was out a charger for a very active month (July/Aug) of RC flying and was charged for a repair that was not really caused by him. He is not pleased with how FMAdirect handled the whole situation. Return to "What's In This Issue" Horizon Hobby is Possibly Selling 72MHz Transmitters that are NOT in Compliance with USA FCC Regulations By Ken Myers      At the PMAC electric fly-in I had an unfortunate incident with my parkzone ZX10 5-Chan FM 72MHz transmitter for my parkzone T-28. I dropped it on its face while loading it into the car and broke the throttle/rudder stick clean off. Rather than trying to get it fixed, I ordered a new transmitter of the same type on August 8 from Horizon Hobby. I ordered it on Ch 54 to match the receiver IÕm using in the T-28. I already had one of the parkzone ZX10 5-Chan FM 72MHz transmitters on Ch 17 that I use as the buddy box (with the crystal and antenna removed) for my student pilot training using the T-28 and on another trainer, the Fledgling, with a Spektrum DX-5e. The new transmitter arrived on Monday, August 16. To my surprise, it was on Ch 17 although my invoice clearly showed that I had ordered Ch 54.      I called Horizon Support the same day I received the transmitter and spoke with a lady who told me that that unit only comes on Ch 17 and that I would have to order the crystal set for Ch 54. That presented a problem to me, as I was aware that the user is not allowed, by FCC regulations, to just swap a crystal in a transmitter to change its transmission frequency. The following link points to the regulation: frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=95&SECTION=645&YEAR=2000&TYPE=TEXT      I have reprinted part (b) of Sec. 95.645 below and used a bold font to point out the section that specifically excludes crystal swapping by the end user. TITLE 47--TELECOMMUNICATION COMMISSION (CONTINUED) PART 95--PERSONAL RADIO SERVICES--Table of Contents Subpart E--Technical Regulations Sec. 95.645 Control accessibility.      (b) An R/C transmitter which incorporates plug-in frequency determining modules which are changed by the user must be certificated with the modules. Each module must contain all of the frequency determining circuitry including the oscillator. Plug-in crystals are not considered modules and must not be accessible to the user.      Obviously the ZX-10 transmitter is in violation of part (b).      The crystal, even though it is accessible to the end user is considered and an internal part. The following section regulates RC transmitter internal parts. I've only reproduced part (a) as that applies. frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=95&SECTION=223&YEAR=2000&TYPE=TEXT TITLE 47ÑTELECOMMUNICATION COMMISSION (CONTINUED) PART 95--PERSONAL RADIO SERVICES--Table of Contents Subpart C--Radio Control (R/C) Radio Service Sec. 95.222 (R/C Rule 22) May I make any changes to my R/C station transmitter?      (a) You must not make or have anyone else make an internal modification to your R/C transmitter.      I did not receive an instruction manual with either of the two transmitters that I'd purchased separately from the T-28.      I have copied part of the FCC regulation section concerning an instruction manual here and have used bold print for emphasis. frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=95&SECTION=653&YEAR=2000&TYPE=TEXT TITLE 47--TELECOMMUNICATION COMMISSION (CONTINUED) PART 95--PERSONAL RADIO SERVICES--Table of Contents Subpart E--Technical Regulations Sec. 95.653 Instructions and warnings.      (a) A user's instruction manual must be supplied with each transmitter marketed, and one copy (a draft or preliminary copy is acceptable provided a final copy is provided when completed) must be forwarded to the FCC with each request for certification.      (b) The instruction manual must contain all information necessary for the proper installation and operation of the transmitter including:      (1) Instructions concerning all controls, adjustments and switches that may be operated or adjusted without resulting in a violation of the rules.      (2) omitted for brevity      (3) Warnings concerning the replacement of any transmitter component (crystal, semiconductor, etc.) that could result in a violation of the rules.      (4) omitted for brevity      All of my other 72MHz transmitters have an FCC ID number on them. The parkzone transmitters do not. With no FCC ID number and no instruction manual I believe that these transmitters may not be type certified by the FCC. I have NOT verified this by contacting the FCC to check the certification. It is a guess on my part. frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=95&SECTION=603&YEAR=2000&TYPE=TEXT TITLE 47--TELECOMMUNICATION COMMISSION (CONTINUED) PART 95--PERSONAL RADIO SERVICES--Table of Contents Subpart E--Technical Regulations Sec. 95.603 Certification required.      (b) Each R/C transmitter (a transmitter that operates or is intended to operate at a station authorized in the R/C) must be certificated, except one that transmits only in the 26-27 MHz frequency band and is crystal controlled (where the transmitted frequency is established by a crystal (a quartz piezo-electric element)).      I was going to quote what can happen if the FCC rules for RC are violated but you can look them up at: frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=95&SECTION=218&YEAR=2000&TYPE=TEXT      During my discussion with the lady at Horizon Hobby support, I briefly pointed out that it appeared to me that the transmitter being handled this way was not in compliance with the FCC regulations. She sent me a prepaid RMA for the return of the transmitter.      I decided not to return the unit and took it to Peter Waters, a licensed RC radio technician, at Kraft Midwest. Peter noted that just swapping the crystal did not present a problem to adjacent channels, but that the power was down a bit. Using his scope and other equipment, he put it solidly on the frequency and tweaked it to return the power to the correct level.      I now have my T-28 back into the teaching rotation and feel good about doing it the "right way." Return to "What's In This Issue"

To Reach Ken Myers, you can land mail to the address at the top of the page. My E-mail address is: KMyersEFO@theampeer.org
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