Sorry but when you said 6v I assumed it was a SLA so your NiMh, must be a 5 cell as they come in multiples of 1.2v. So I agree the simplest solution is a Rx battery pack and disconnect the BEC supply. (May need to remove +ve wire from ESC(s) plug?)
Hi Will, Sounds good to me👍 I like the Action Electroncs stuff as well, have their dual ESC with rudder mixer which I want to try in my long thin destroyer to reduce the turning radius. Was misled about the SLA by a previous post🤔 Makes sense re the BEC which I believe is 5V 1.2A. I prefer a separate RX batt anyway😉 BUT: if you run a 6V NiMh down to 5.6V you are close to the Deep Discharge zone which will seriously damage the battery and drastically shorten it's life 😲 Threshold voltage is 1.0V per cell, so take erratic control as a warning that the battery is flat and come home soon! Look forward to your Sea Trials report. Cheers, Doug
Doug, The 6volt battery is currently an NiMh battery not an SLA. The problem was that according to Mtroniks the minimum voltage to the ESC to adequately run the BEC connection is 6volts. That is why I was getting erratic control when the battery voltage was 5.6 volts. The action speed controller will work 2-12 volts and I am going to use a separate receiver battery as suggested by Dave Milbourn just to make sure. Regards Will
hi Will, I agree with replacing the SLA. If you don't want to go LiPo cos of chargers etc etc how about a 5 cell 6V NiMh? much lighter than the SLA For the ESC switch to the Mtroniks Viper Marine Micro 10. That handles motors up to 550 can size, 10A motor limit, and runs off 4.8 to 12V 👍👍 I use these very happily on ships running 2 or 4 540s. A destroyer and a cruiser. Both about 54". http://www.mtroniks.net/prod/Boat-Speed-Controls/Viper-micro... You can get 'em about 5 quid cheaper here https://www.cornwallmodelboats.co.uk/acatalog/Mtroniks-marin... There are also 15 and 20A versions if you want to run both motors off one ESC 😉 Cheers, Doug 😎
I think it would be worth the risk of running the DC Motors at 7.2v (NiMh) or second choise 7.4v (Lipo) and get rid of the 6v lead acid battery. The chance of damaging the motor is limited, the battery packs will be lighter than an equivalent lead acid, but will need to by a charger as well. Always put a fuse in line rated 5 amps below that of the ESC. Or buy two higher voltage motor? only £6.99 each plus P&P link copy and paste into browser address:- https://howesmodels.co.uk/product/ style='background-color:yellow;'>graupner-speed-600-8-4v-motor/
Evenin' Martin, Attached the Graupner Speed 400 specs. Pic 1 is the brushed version nominal 7.2V, pic 2 the brushless nominal 11.1V. Don't think the brushless 400 is any good for your Hornet, not enough shove? Ca 14400rpm OFF LOAD with a 3S LiPo. The brushed version might be though. It should run OK up to MAX 9.6V. Try 'em and compare. The 62mm in the TP2408 seems to include the shaft length! It might well drive your Hornet but maybe not record breaking😉 The other, blue one, might! But who knows as it's anonymous 😲 On closer inspection I suspect the blue one is an inrunner!? Cheers, Doug 😎 PS: Specs for your Simprop ESC "5 bis 10V. Strom: 12A (25Amax). 5-8 NiCd / NiMH. BEC: 5V/1A.Gold-2mm Buchsen. Maße: 27x11, 5x8, 5mm. Gewicht: 5g. " I.e. 5 to 10V, Current 12A (25A MAX). So OK for your Taycols on a 6 to 9.6V NiMh👍 Not sure if it does backuds though, probably not!
Help required please, I have two Graupner Jumbo 540 6volt motors in an eboat circa 1978, I had fitted an Mtroniks speed controller replacing the Bob's board only to find that when the voltage dropped below 6 volts down to 5.6 volts I was experiencing intermittent operation of the esc. I have been informed by Mtroniks that the minimum voltage for operation of the esc is 6volts. Graupner have also confirmed that the maximum voltage for the Jumbo 540 motors is 6 volts. Do I have any alternatives other than refitting the Bob's board?
Hi George, Had this snag with my Graupner Graf Spee as well. In my case the stbd prop tube was misaligned 😲 Major surgery 😡 First off; it's unlikely that the motors are perfectly matched, but if the difference is that noticeable I would suspect the cause lies in propshaft resistance and / or dry motor bearings! I would disconnect the prop shafts, oil the motor bearings and run them in a bit off load for a few a minutes. See if you notice a difference there at low speeds. Also; remove both shafts; clean and oil. Clean the tube end bearings with a pipe cleaner and some light machine oil. Squirt some Teflon grease into the tube from the prop end. I use a small plastic syringe for that. Before reassembly check as far as possible that neither shaft or tube is bent at all🤔 If all seems straight reassemble and run the motors at medium speed a minute or two then slowly and see if you can still detect a difference. Reduce the throttle gradually until the motors stop. If one stops significantly before the other that suggests extra friction in that drive train; misalignment somewhere! Thrust washers too tight? BTW: which motors? One ESC or two? Hope this helps! Cheers, Doug 😎
Hi Doug, A phenomenal place, the Deutche Museum. I visited it when I was working in Munich back in '87/'88. I agree with the views on scratch building. It's the difference between Model Making and model assembly. Although, I have to say that, although my 3D printing has been poo-pooed in this forum as non-traditional - is anybody out there still using horse-hoof glue and bamboo strip - most of the stuff I print is self designed. All the hulls I have built have been hand built. I do have one kit with a moulded hull - a Graupner Optimist- it's been in the garage attic unfinished since 1993. I must get round to it one day. But before that, there's this Ferret plan in the MB mag. That looks interesting.....
[Score: 8/10] Capable of 6mph and a runtime of 60mins Single Propellor (3 Blade 25mm) Direct Drive to a 380 (3 Blade) Powered by NiMH (6v) 3Amp/h Batteries Controlled Through Mtronik 15 amp (5Amps) ESC - Comments: The boat is a Graupner kit from the late 1970s and has recently been updated with new Spektrum radio tx and Mtronik speed controller. and
As promised (or threatened?😁) stage two of the hull work and thoughts on motorisation. The hull was sprayed with two coats of grey primer/filler. Pic1. As usual this showed up the remaining imperfections (pics 2 & 3), but I'm not going to worry about them until I've got prop shaft tube and rudder stock sorted out and permanently fitted 😉 After my attempts to make and thread a 3mm prop shaft went awry Martin (Westway the Mechanicals Master👍) stepped in and made me a decent one complete with a bushed stuffing tube 👍 Vielen Dank Meister😊 I did however manage to make a 4mm to 3mm reducer so that I could fit a Rabeosch 35mm prop as seen in pics 2 & 3. The tube and shaft from Martin, arrived Saturday an' he only made it on Monday😊, have been dry fitted so that I can start setting up the gears, necessary to bring the drive down to the prop shaft fitted very low down in the hull, and motor mount. Pic 4. Motorisation: (Remember folks - this kit was designed and built as a static model!) I want to use the old 1950s Taycol Target motor which my Dad originally fitted in the Sea Scout which I have renovated and upgraded to brushless. See Build blog 'Sea Scout - Jessica' Many of you will know that the Taycol motors were field coil motors, meaning that they have no permanent magnet around the rotor coil, and thus reversing the battery connections to the brushes had no effect on the direction of rotation, as this simply reversed the magnetic fields of both stator and rotor coils🤔 To counteract this so that the motor could be used in both forward and reverse with a conventional brushed ESC I modified the motor slightly (separated the two coils) and built a simple converter board to connect it to the ESC. Again see the Sea Scout blog for the details of the conversion. Basically; once the field coil and brush-gear (rotor coil) have been separated a simple diode bridge can be used to apply the output of the ESC to the motor. This enables the reversal of EITHER field OR rotor coil polarity, depending on how you connect the converter to the motor. Thus reversing the direction of rotation of the motor. Beneficial side effect is that the diodes also suppress the commutator sparking😊 In my case, with the Taycol Target, I also cleaned, flattened and polished the commutator. Thus significantly reducing the potential for spark generation in the first place! A peculiarity of the Taycol motors is that they all use metal brushes, pressed phosphor bronze strip, so they need oiling! DO NOT oil conventional brushed motors with carbon brushes unless the brushes are exchangeable or you want to have to buy a new motor!!!!! Pics 5 & 6 show the proposed position of the Taycol in Gina 2 and pic 7 the prototype converter board I knocked up to test the motor, together with a Graupner Navy V30R Marine Brushed ESC. Details and results in the Sea Scout blog, including video of the sparks and oscilloscope pics of the drive waveforms before and after conversion! The latter showing the spark suppression effect of the converter😊 Some samples attached - last 3 pics. Pic 8 pic shows a more compact version of the converter, one of a few types I'm doing for Martin's various Taycols as a trade for the prop shaft he made for me and some useful material he sent. Thanks mate👍 Next steps will be 1) mounting the gears correctly on the shafts, requiring the manufacture of a 3/32" to 4mm adaptor and a 1/8" to 4mm adaptor, and keying them to the shafts - Hooray for mini milling machines 😉 2) manufacturing bushed end plates to hold the gears in place, 3) fitting the motor mounting platform. I'll probably borrow from my experiences of real shipbuilding and do this as a suspended 'false floor', i.e. mounted on stiff springs to enable adjustments to optimise the gearing mesh! On real naval ships this is done to improve shock resistance and to minimise engine noise / vibration conduction to the hull, thus significantly reducing the acoustic signature of the ship. Not that I'm tooo worried about being torpedoed 😁 Worth a try😉 Pic 9 shows the cleaned up and renovated Taycol Target motor. Pic 10 shows the drive waveform complete with sparks before modification.🤔 Pic 11 the cleaned 'forward' waveform with the converter board. Pic 12 the cleaned 'reverse' waveform, no suppression capacitors needed 😉 More soon folks, Cheers, Doug 😎 PS Along the way a new keel was fitted as can be seen in pics 1 to 3. The original builder had 'buried' the keel in the hull planking! 😲
Guys, hi I came down to hartsholme today to trial run the build and was made extremely welcome thanks greatly. Er motor widthThe motors are T4A from mobile marine they were extremely hot so prop size adjustment is needed. I am building again this time an inshore mine sweeper I have 50 mm graupner props on at the moment and am looking for a pair of motors to run off 12v LAB with 15 amp speed controllers per motor but cooler with out going to big I have 50mm per motor width allowance and 70mm length. I would like to keep up speed as inshore sweepers were fairly nippy 20knots real time. Is there any recommendations please ,apart from rebuild again. Regards Nobby
Hi Martin, First your last question😉 "What DO you do with a 3rd channel?" Example: 5 foot destroyer! 1 Throttle. 2 Rudder 3 Gun rotation, servo and pulleys 4 Torpedo tube rotation, servo and pulleys 5 Smoke switch, servo and microswitch (Smoke could be linked to the ESC to free this channel for the ASDIC pinger!) 6 Split into four functions (by misusing the gear down lever on my Graupner MC-10😉) for Whoop whoop, Fog horn, searchlights and signal lights, NAV lights. All switched via a home brew decoder / switch board and 5V relays! Alles klar? 😉 Re the DX5e; If I were you I'd let a (supposedly?) Spektum trained guy look at it first. With luck he'll have a service manual or at least a circuit diagram, which I don't 🤔 and should know the binding procedure backwards. I could only do some rudimentary tests without the circuit diagram, and make some educated guesses. I could at least try binding it with a variety of Rxs, including my Spektrun RXs which all work faultlessly with my DX6. Up to you, will PM my address anyway. I could at least check, with a simple RF meter, if the damn thing is transmitting at all! Just thought - if you're going to smash it anyway ........ 😉😁 Cheers, Doug 😎 PS: 4th attempt at the prop shaft for the cutter also failed 😡 She just does not want to get her bum wet!! Too long 'on the shelf' 🤔