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The 70-year US Coast Guard semi-deck. All-metal construction, 2 x MIG 480 motor, standard servo, model illuminated on two circuits. One light mast, position lights and cabin. The second lighting circuit in the hull of the ship and the outdoor lighting around the superstructure. There are no labels on the model yet, I'm waiting for the fabrication. Battery 1 x LiPol 4000 mA. The total construction took me half a year. I made the hull made of laminate from my friend in Slovakia. The superstructures themselves are made of laminated boards. Part of the light bulbs are 6V lamps and the strobe with positional lights are the LEDs of the light triggering through two RC switches.😉
[Score: 8/10] 27"/2600g USCG POINT GLAS Capable of 11mph and a runtime of 80mins Twin Propellors (4 Blade 25mm) Direct Drive to a MIG 480 (4 Blade) Powered by LiPoly (7.4v) 4Amp/h Batteries Controlled Through DSYS 72A ESC - Comments: The 70-year US Coast Guard semi-deck. All-metal construction, 2 x MIG 480 motor, standard servo, model illuminated on two circuits. One light mast, position lights and cabin. The second lighting circuit in the hull of the ship and the outdoor lighting around the superstructure. There are no labels on the model yet, I'm waiting for the fabrication. Battery 1 x LiPol 4000 mA.
Hi TJ, Answer to both questions is NO! 1 Connecting all the ESC switches together is like leaving all three of the red wires in the RX leads connected. If you mean a main power switch for the ESCs (not the little slide switch attached to the ESC) then consider that the switch would have to cope with a current of 3 times the max current rating of the ESC!!! For example; for 30A ESCs that would be 90A 😲 pretty big switch! 2 The object of the mixer is to control the ESCs of the two outer motors depending on the rudder setting, not to replace them somehow. If you mean two of the little slide switches being made redundant; again NO! They are there to switch on the ESC's internal circuitry, incl. BEC, without it they won't woik 🤔 Cheers, Doug 😎
I had realised that John, the acronym DEAC had simply revived some ancient memories of my early days in mobile and hand-portable radio engineering. Circuitry and components, early ICs etc, were moving on much faster than battery development could keep pace. Good to hear from you👍 Pecker up old chap, with you in spirit. Best wishes, Doug
Hi, Doug. I’ve been plugging away at some of the work that doesn’t call for really good eyesight, such as stripping off the “Richardson” name & repainting here & there. I still can’t see well enough to work on the microscopic circuit board modifications. The last of the parts that I ordered arrived last Thursday so everything is finally on hand. I hope the infection goes away for good soon & stays away. It’s really discouraging. Fingers crossed for better days. Pete
Doug a quick one for you I've got a wall wart with a blown / burnt resistor. The rest is working fine and I would like to replace the resistor and put back into use with the model it belongs to. I can't read the res as its burnt black (output leads got shorted.) It's the last one in the circuit ( output lead ) Voltage up to it is 15v. It is to charge 7.4v Ncads/ Nimhs AA/AAA packs. I can't work out what the value should be. Should be simples for you if you'd be so kind as to do the maths for me. I'll luv ya forever if you do. Not literally of course but ye know warrimean. Regards John👍 No comments like ducky etc please. Oh yes remember your remarks re our local pubs? The owner of our nearest the STAR ( ex plough Still got one on roof of main windows) rang our bell. He'd seen Marg go off in an ambulance 2 days on the trot and wanted to know if he could help.( We were customers now and again) He brought a wine for Marg and a nice flask of bitter each for Ant and I. Luvverly. He stayed about 2 hours nattering and when he left he said ring him if we needed help any time. We had the same offer from a young chap who helped Marg up the path too with a mate. Our adjoining neighbour looked after their shopping. Starting to see some signs of neighbourliness again it seems.👍😁.
Hi John, think somehow you've got the wrong end of the stick!🤔 All BECs are Battery Eliminator Circuits of one sort or another. The objective is to eliminate the separate receiver battery, sometimes necessary purely to save weight and/or space in small models. If you do that then the RX power must come from the main drive battery, which then has to supply all RX functions; servos, switched lights etc etc. Personally, if the boat / ship can carry it, I prefer to use drive batteries for just that and use separate battery for the RX and special functions. Some of which, like smokers for instance can be current gobblers. Cheers, Doug 😎 PS If you ever find a way of eliminating all batteries and still get the RX to work and the boat to move PATENT IT QUICK!! 😁 Cheers, Doug 😎 Hmmm! Maybe a raft towed behind with an array of hi-current solar panels!? 😁😁 Years ago in my work in NAVAL COMMS systems I once suggested to a shipbuilder, who was complaining about the number of antennas needed, to put some of them on a raft behind the ship 😉 Now they are doing just that with antenna buoys from submerged submarines! No credits 🤔 ... SIGH 😉
Hi Martin, 'Linear' in this context just means more or less a passive analogue device, and when it's on it's ON full stop. Decades ago I made my own with a simple one chip circuit using a 3 legged voltage regulator L7805 5V 1A and they're still going strong😊 The SBEC uses a fast switching type of power circuit, similar to the pulsed DC outputs of the ESCs. The switched type is an active device and is more efficient, less battery power wasted as heat, but can cause interference with older 27 / 40Meg RC receivers. Shouldn't affect 2.4Gig sets though. Cheers, Doug. PS even in a blackout I think I would find my way to the wine cooler or my malt whisky! 😁😋
Hi Martin, BEC is the Battery Eliminator Circuit built into an Electronic Speed Controller. UBEC is a Universal BEC which takes power from the main (drive) battery and supplies 5V or 6v to the receiver. It can be a linear device. SBEC does the same job as a UBEC but is a so called Switched device which is more efficient than a linear. So functionally for our purposes there is no difference. Alles klar Herr Kommissar!? 😉 Cheers, Doug 😎
Hi TJ, that instruction is quite correct👍 It indicates that the ESCs have Battery eliminator Circuits (BEC) which means that there is an internal circuit which 'syphons' off 5V from the main drive battery to supply the receiver via the red wire in the ESC to RX cable. The ESC itself takes it's power from the drive battery. If all three red wires are left connected this will cross couple all three BEC circuits and may well damage the ESCs. The RX only needs one power supply! 😉 In my multiple shaft boats I usually disconnect all the red leads from ESC to RX and fit a separate RX battery. Cheers, Doug 😎
Decided to separate the two power systems; one to the port ESC and motor and the other the starboard. Hope this will reduce interference between the motor systems. Have also reverted to a remote battery powered Rx rather than the BECC system, again to reduce possible interference. The modifications did not resolve the problems. The squeal and stutter are still present, but much reduced. Sounds rather like a slipping coupling, but as these have been checked many times they can be eliminated. Apart from the squeal and the stutter, everything works well. The squeal /stutter occurs at start up, when it happens the control is returned to neutral, If the motor is immediately reselected, usually the problem goes away and the motor runs up cleanly. It only occurs when both motors are selected at the same time. Either runs up cleanly when selected individually. Interestingly enough, did some research on various Model Boats site and found some references to RF interference, no specific solutions though. Also examined some Aero modeling sites as they use powerful brushless motors with ESCs. There is some history of the problem there. Evidently when the mosfets (?) of the ESCs convert DC to AC, RF interference is generated. It can often be addressed by using ferrite rings on the ESC control leads. My latest ESCs actually have ferrite rings, so the problem must have been anticipated. This might account for the latest reduction in squeal and stutter levels. Am at a loss to think of any other modifications, so decided to conduct a water test. Maybe it is a characteristic of brushless motors, but their control response seems “ragged”, not smooth as with a brushed. Anyway, the squeal and stutter seemed reduced yet again, perhaps the water load damped them down. Was able to start exploring both the performance envelope and the viability of the brushed centre shaft motor. First impressions are that on a 2S battery the performance is fine, but it sparkles on 3S. On 3S the stutter and squeal are more pronounced though. Intend to do further trials but, unless something unexpected occurs, now plan to use 2S power. The centre brushed motor idea works well, this layout seems a good compromise. Will design a simple switching circuit to ensure the brushless motors can selected separately. This will avoid the inadvertent operation of both brushed and brushless unintentionally as they are on the same control stick. The brushed can then be used for low speed operation. Returning to the problem of squeal and stutter – has anybody else experienced this and how was it resolved?
OK, found some! https://www.ebay.com/itm/8pcs-JUGEE-3000mWh-1-5V-rechargeabl... Interesting that they all quote mWh instead of mAh! I.e. energy instead of capacity! Power being V x I (Amps) divide the mWh rating by the nominal voltage to get an approximation of the capacity in mAh. Saves integrating across the varying voltage during a discharge cycle, i.e.'On Load' 😉 Thus these 3000mWh cells seem to have a capacity of around 1800mAh. Which is considerably less than the typical 2500mAh of an alkaline or NiMh AA cell. Also, to produce the output voltage of 1.5V from 3.7V Lithium chemistry the cells have an internal voltage regulator, which also must consume some power, albeit miniscule. Something else which can go wrong🤔 Summary; yer pays yer money and takes yer choice! Seem rather expensive to me for what they deliver. Depends what you want to use them for. Might be useful in my Sony camera but I wouldn't use them for any high current load in a model. OK perhaps for LED lighting circuits which only need a few tens of mA. Here a list of battery types, sizes and chemistries for reference. https://www.wikiwand.com/en/List_of_battery_sizes#/overview Cheers, Doug 😎
Neither can I Martin! "The transmitter used two vacuum tubes wired as a multi-vibrator with a tank circuit to constrain emissions to somewhere near the 27 M/cs band (same as MHz, but that name came later). With not a crystal in sight, transmitter frequency drift and battery voltage drain was a problem, so careful tuning just prior to short flights was the order of the day." http://www.modelenginenews.org/cardfile/ed_radios.html#3 Cheers, Doug 😎
Mornin John Re detector circuit: It's not very complicated, only 3 or 4 actual components. The clues are good RF diode and a very sensitive meter! I just bought a couple of 300microamp full scale meters. Will do a little blog when I've tidied it up and boxed it. Re Heli: can you post or mail me pics of the TX, RX and ESC please. Brushed or Brushless motors? Given manufacturer / model numbers I might be able to figure out what the pissibolities are. No promises though 😉 Sounds to me like the TX stick is set up for forwards / backwards like a normal car or boat set up. I.e. for 0 to full speed in either direction is only half the stick travel. For aircraft 0 is full down, giving you the full stick travel for the speed range. The ESC probably needs to be 're-educated' and the TX throttle stick re-programmed, IF at all possible with the TX you got with the Heli. Re " P.S. Signals come from where Doug?" - Don't understand the question John ?? Cheers, Doug 😎