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Hi Granpa, Just saw this in my e-mail Notifications! "Grandpa here...good conversations here. Some of you are talking about the TX. What is the tx? What is Esc? I will check to see if I am in Mode 1 or 2." Strangely I can't see it here in the forum??? TX is shorthand for transmitter, ESC means Electronic Speed Control. I see you are using a Spektrum TX (!). So am I - the DX6. Please post the model number of your TX then I can maybe download the manual. Now time to make my cappuccino 😋
Hi Gdaynorm (Why does that name make me think 'strine'?) 😉 Yes you are absolutely right Duratrax seem to specialise in cars & buggies. The Sprint always seems to appear in the context of the Evader buggy series, also it is listed as discontinued on the Duratrax site! http://www.duratrax.com/downlo ads/discontinued.html Nothing lasts for ever!! Maybe it is not happy driving two motors? What is the total current drawn? Since it seems almost certainly to be an overheating problem is there sufficient cooling air flow through the boat? Recycled 5V DC PC processor fans can be useful to help here. Since you can test motors by feeding directly I assume they must be brushed. Are your batteries, LiPo or NiMH? In both cases the Sprint has a low voltage cut-out. 3.3V for LiPo, 5.0 V for NiMH. Maybe the cut-out circuit has a hysteresis effect. This means that if the battery recovers slightly when taken off load, and cools?, the boat runs again - until the cut-out point (thermal or volts) is reached again! I would expect the interval between cut outs to reduce slightly with each cycle until the battery is totally depleted. This effect is also noticeable with sealed lead acid accumulators. I would be tempted to bite the bullet and buy 2 ESCs designed for marine use (e.g Graupner Navy VR series or Viper Marine or US/Canada equivalents) and a 'Y' cable to run both in parallel from one RX port. Then each ESC only has to handle half the load. And ensure sufficient cooling air flow, or even water cooling!? How big and heavy is the boat, what type are the motors and what size & type are the props? Cheers from Munich, Doug 😎
Well I'm damned! Checking my VR30 ESCs I found attached spec! Never noticed this offset in operation before, maybe because naval ships don't have much freeboard at the stern so I take it very easy anyway. You live and learn 😎But then that's what a forum is all about.👍 Sailing here today near impossible, only 3°C and sleet
Good clue! - extract from manual re set-up "1. Set throttle trim to neutral and turn on the transmitter. 2. Press the ESC on/off button. The LEDs will light, one green, one red. 3. Wait 3 seconds, the LEDs will change to blue. Your ESC is now set. 4. The ESC has an automatic LiPo cut-off. One flashing red LED means your battery is low and the cut-off has activated." Note point 4 !! Are you using LiPo or NiMH? Also- "Problem: Model runs properly, then motor goes dead. ➤ The built-in thermal protection may be automatically shutting down the ESC due to overheating conditions. Check for binding drivetrain, bad motor or incorrect gear ratio. Adjust gear mesh, replace motor or change gear ratio. Allow the ESC to cool and try again." ESC seems to be mostly used in buggies - above is extract from the Duratrax Evader EXT2.4 manual. Thus, assuming direct drive, 'changing gear ratio' for us means change the prop! May also have been the cause of the blue ESC problems? Which version of the Sprint? There are Sprint DTXM1200, Sprint 2 DTXM1205, and Sprint Waterproof DTXM1220. All with slightly different specs and motor requirements; brushed / brushless. So what is your setup, End to End; battery to prop?
"As an ex flier I do believe all engines had the throttle idling with the stick fully back and I have always associated forward with stick up leaving backward for stick down." This might be the clue! This is what I meant by TX mode. I note that Grandpa has a Spektrum DSM set, he may have it in Mode 2 the usual flier mode, as my DSMX 6 was delivered. If so first of all maybe switch to mode 1 to put throttle (full range) and rudder back on the right stick Channels 1 and 2. Then check the TX programming (offset) on Ch1 and centre it. Then worry about the ESC. Had a similar discussion a few months ago with Andy at Micron Radio Control about the set up for some miniature receivers for my plastic magic! Still getting to grips with programming the Spektrum. Until then all Sea Trials done with the old MC-10 40MHz kit. 😎
Hi Dave, One lives and learns 😉👍 I'll check this for this effect (bench tests!) with the kit (Graupner Navy V30) I'm building into my Belfast and Graf Spee, but up to now with brushed and 'conventional' ESCs I've not noticed it. Not got into brushless yet, but might do soon for Dad's old Sea Scout, which is my only single screw boat. Agree with the same settings philosophy, I do the same. Watch this space! 😎
Seems like we have two case here! Surely if Frank gets forward motion with stick back and vice versa he just needs to reverse the servo at the TX? I had the same problem with my old Graupner MC-10 40Meg set. If he's using a 2.4 Gig set it might be related to which mode he is using, normally 'out of the Box' set up is for fliers with mixer settings we don't need in boats. With Grandpa; don't know as he hasn't described the reactions to stick forward or stick back. My money is still on TX set-up. 😎
This triggered my curiosity! So have just ordered the Busing in-line 150A Power Analyser, €12 😊 Anyone looking for such a device can find several review videos here https://www.youtube.com/watch? v=Lxv9Rozs774 Happy hunting 😎
Thanks for the watt-meter tip 👍 Will check around my German / Austrian sources, might be worth a trip to Salzburg 😉 I sometimes forget that others outside the industry may not have access to the sophisticated test gear that I do. Time to eat humble pie 🤔 Cheers from Munich 😎
"But you know the best indication is when a two second task takes 2 hours as you seem to have lost the parts you started with and then find some of them and again lost the bits you found the very first time." Tell me about it! 🤔
Wow! Super project 👍 Here the complete history of the ship (Thanks Wiki 😉) https://en.wikipedia.org/wiki/ HMS_Lion_(1910) What's the state of play? How far have you got? Please post some more photos, inside and out, and a list of components; motors, props, ESC, battery, RX and TX. Then maybe we can see what the next step might be. Cheers Doug 😎
?? I've never heard that! The ESC just does what the TX tells it to. Throttle not centred on TX; Offset? Trim? Brushed or Brushless? If brushed: brush wear might play a minor role since most wear naturally comes from the forward direction. Lower resistance from prop in reverse? My money is on throttle offset at the TX. 😎
PS to Damon If you can start a Build Blog, then you have a 'memory' to refer to and we can keep an eye on progress and help if we can with tips & tricks etc. Will monitor progress with great interest. Cheers Doug 😎 AKA 'The Old Sea Dog' (my office nickname!)😉
I agree John, modelling by 'proxy', could have been interesting 😉 I wish you the very best of luck Damon, and don't be afraid to ask us questions. You can always refer back to the written answers. The only silly question is the one you don't ask! 😎
Hi, plans for Victorious of the same class are easier to find, for example http://www.fleetscale.com/stor e/gb/hms-victorious-ww2-aircra ft-carrier/503-1-128th-hms-vic torious-drawings-plans.html You can also find photos and info on Illustrious (WW2) here http://www.fleetairarmarchive. net/ships/ILLUSTRIOUS.html Attached is sample photo and a simple GA plan I found. You could also try here https://blueprintsofwarships.c om.pl/Profile_1a.htm They print to order so delivery sometimes takes time, in the past I bought PDFs for 'instant' download but they seem to be stopping this service at end of April 😲so hurry up! My long term project is HMS Ark Royal WW2, plan hanging on the wall for 2 years now!! Good luck Doug 😎 Doug 😎
Ahoy Shipmate, Try this http://www.model-dockyard.com/ acatalog/John_Lambert_Warship_ PLans.html I've used several of John's plans, especially for WW2 naval weapons. Let me know how you get on, if you don't find anything I'll check my sources here in Germany. Good luck. Doug 😎
PPS Allan pondering the 'spec' of your LiPo "5300mha -50c-14.8v-4s1p-78wh" The wh rating = Watt Hours. i.e how many watts of power it can deliver in 1 hour. Since Power (P)= Volts(V) x Amps(I) (simple DC calc!) I=P/V i.e. 78/14.8 = 5.27, which is where the nominal capacity of 5.3AH (5300mAH) comes from. I don't think the battery is your only problem, i.e. a) the ESC was fundamentally defective, b) your setup is drawing too much current for more than a few minutes running on a 5 to 7 AH battery with no reserves. Good luck. I run a 1.3 metre destroyer on 2x540 brushed and 2x6V 4AH (4000mAH) SLA and it trundles around for 2 or 3 hours, and can still outrun several wannabee 'boy racers'! 😉
PS Allan, there are several water jackets / spiral tubing available for cooling brushed motors, try Hobby King, or just get some alu and silicon tubing and make your own. Apply some heat conducting paste between the jacket or tubing and the motor casing (as used in the electronics industry for mounting power transistors, processor chips etc) available in tubes also in model shop site for a few dollars. Good luck
Hi Patto, forget the 'watt meter' and consequent P=IV -> I=p/V conversions! What you need to measure is the actual current drawn, especially the stall current, if you can manage that without getting any fingers chopped off 😡 On the lake anything can choke the prop so just testing 'free running' is not the whole answer. Sounds to me simply that your setup is drawing so much current that any battery or accu will go flat in a few minutes. Your example of a 5300mAH (i.e. 5.3AH) means that in perfect (!) condition, fully charged and almost zero internal resistance (int. cell resistance wastes power so buy the best quality you can possibly afford) it can theoretically supply 5.3 Amps for 1 hour. or 53 Amps for ~ 6 minutes (1/10 hour). and so no. LiPos with C values of 130 sound great BUT the discharge C value is related to the AH rating. So taking your example of 5300mAH = 5.3 Ah 130C = 130x5.3 = 689Amps! The Accu would supply that for ~ 27 seconds before departing to the great recycling centre in the sky! If you ever decide to try such an experiment PLEASE let me know in advance and I'll fly over the record the event for posterity 😉 Seriously though folks: I can't comment on the prop/motor setup, one of my weaknesses - I always check my stalled motor current draw with an ammeter before selecting the ESC - but as an electronics engineer I do have some idea about power supplies and circuit requirements etc. Can't imagine that your setup exceeded the 160A (short term remember!) rating of the ESC so that seems to be faulty, but you still need to find out what current your setup will draw under severe load i.e. stall. If just holding the boat cause blow ups then something else is fundamentally wrong 🤔 Bit long-winded perhaps, much of the above makes sense but not the whole story, time to cut to the chase I thought. MEASURE THE CURRENT! Good luck. Doug 😎 By the way the above comments about lead acid & hi current are OK. They are more useful for long term supply of low to medium currents. I still use them in some larger scale models (~ 1.5metre naval ships) as they provide useful ballast (i.e. payload) instead of JUST ballast! The 20HR of your lead acids refers to the Hourly charge Rate, i.e 1/20 of the capacity in AH, in your case 7/20 = 0.35A or 350mA.
PS On the recycling note I find that the alu foil from butter tubs (e.g. Kerrygold) is excellent for simulating diamond textured steel decks, companion ways, step & ladder treads (in German - riffle!?) in scale ~ 72 to 100 😎
Hi from Munich There is a saying amongst ship modellers here in Germany "Schiffsmodelbauer sammeln alles was nicht unbedingt in zwei Wochen zu stinken anfängt !" "Ship modellers collect everything that doesn't start to stink in two weeks!" On that happy note Goodnight from Munich 😎