Ronos Posted January 28, 2020 Share Posted January 28, 2020 Hello, I have a 5050/60 850kv Brushless motor with a APC 14x7 electric prop on a 80c ESC with a Turnigy 4S 5000mAh lipo, powering a VQ Hurricane 60 weighing in at 4.5kg. Please bear in mind that the power plant is recommended from the supplier. When powered up to full throttle there seem, in my opinion,not as much thrust as i would expect. Anyone got a opinion, just want to be sure before the maiden. Thanks Ron. Edited By Ronos on 28/01/2020 12:15:59 Quote Link to comment Share on other sites More sharing options...
Phil Green Posted January 28, 2020 Share Posted January 28, 2020 What does your power meter read? You should be drawing over 60A to get a kilowatt from 4S. Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted January 28, 2020 Share Posted January 28, 2020 Couldn't find your exact motor, but when I ran a 850kv motor through Ecalc with a 5000 mah 4s and APC 14 x 7, I got 5.2 kg static thrust, 10,000 rpm, 1400 watts and 100 amps. Have you checked the amps your set up is drawing Quote Link to comment Share on other sites More sharing options...
Dickw Posted January 28, 2020 Share Posted January 28, 2020 Can you give us more details on the motor please? I ask that because a quick check on the recomendations seem to suggest a 5055/06 580kV motor which has all the same numbers but not necessarily in the same order! With an 850kV motor an 80A ESC might be in trouble. Do you have any current or rpm readings from your test run? Dick Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 28, 2020 Author Share Posted January 28, 2020 Thanks for you all for your replies, can I get back to you later, I have a lipo on charge. Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 28, 2020 Author Share Posted January 28, 2020 Frank, it's a Electrospeed brushless motor and Electrospeed ESC, supplied from Hobby Plastics. Quote Link to comment Share on other sites More sharing options...
Andrew Calcutt Posted January 28, 2020 Share Posted January 28, 2020 Get a quantum 60 motor on 6 cells that would give over 1500 watts and will fly it well.Any less than 1500 watts won't be enough. Quote Link to comment Share on other sites More sharing options...
PatMc Posted January 28, 2020 Share Posted January 28, 2020 If this is the model then according to spec your's is about 1Kg overweight. I presume 850kv you quote is a typo, according to it's spec the recommended motor is 580kv . Which would suggest that it should be running on 6s for this model. Unfortunately the motor spec doesn't mention it's max current but IMO the model would need it to be pulling in the region of 45A at WOT. Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 28, 2020 Author Share Posted January 28, 2020 A quick confession, I not really sure on how the check for amps/ wattage,etc,etc, but I have just checked the rpm with a tachometer and divided it with the voltage of the battery, 8130rpm÷14.8v and it has came up with about 550 which I understand is the kv of the motor. Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 28, 2020 Author Share Posted January 28, 2020 here is some more info on the motor. KV 580rpm/v power: 1280w idle current: 2.3 esc 80A Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 28, 2020 Author Share Posted January 28, 2020 Posted by PatMc on 28/01/2020 13:46:13: If this is the model then according to spec your's is about 1Kg overweight. I presume 850kv you quote is a typo, according to it's spec the recommended motor is 580kv . Which would suggest that it should be running on 6s for this model. Unfortunately the motor spec doesn't mention it's max current but IMO the model would need it to be pulling in the region of 45A at WOT. Probably is over weight, I had to put in 40oz of lead to get it to its COG. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted January 28, 2020 Share Posted January 28, 2020 Sorry but your 4S battery won't cut it. You need 6S aiming for a maximum peak of 50A with a fresh battery dropping down to the 45A PatMc quotes. When playing at this sort of power level a wattmeter is essential, without it you will have real problems as you are just taking a stab in the dark and hoping nothing goes pop. A wattmeter simply plugs between the battery and ESC and gives you a direct measurement of amps, volts and you guessed it, watts. 40oz of lead? The 6S battery of around 4500mAH pushed as far forward as possible will help, but that is still a lot of lead. Have you mounted servos in the tail by any chance? Edited By Bob Cotsford on 28/01/2020 14:30:12 Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 28, 2020 Author Share Posted January 28, 2020 Posted by Dickw on 28/01/2020 12:37:16: Can you give us more details on the motor please? I ask that because a quick check on the recomendations seem to suggest a 5055/06 580kV motor which has all the same numbers but not necessarily in the same order! With an 850kV motor an 80A ESC might be in trouble. Do you have any current or rpm readings from your test run? Dick Hi Dick just the rpm which was 8130. Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 28, 2020 Author Share Posted January 28, 2020 Posted by Bob Cotsford on 28/01/2020 14:12:28: Sorry but your 4S battery won't cut it. You need 6S aiming for a maximum peak of 50A with a fresh battery dropping down to the 45A PatMc quotes. When playing at this sort of power level a wattmeter is essential, without it you will have real problems as you are just taking a stab in the dark and hoping nothing goes pop. A wattmeter simply plugs between the battery and ESC and gives you a direct measurement of amps, volts and you guessed it, watts. Thanks Bob, I will get one and get back to you all later. Thanks for all you help. Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 28, 2020 Author Share Posted January 28, 2020 Posted by Ronos on 28/01/2020 14:15:16: Posted by Bob Cotsford on 28/01/2020 14:12:28: Sorry but your 4S battery won't cut it. You need 6S aiming for a maximum peak of 50A with a fresh battery dropping down to the 45A PatMc quotes. When playing at this sort of power level a wattmeter is essential, without it you will have real problems as you are just taking a stab in the dark and hoping nothing goes pop. A wattmeter simply plugs between the battery and ESC and gives you a direct measurement of amps, volts and you guessed it, watts. Thanks Bob, I will get one and get back to you all later. Thanks for all you help. Which watt meter would you recommend Edited By Ronos on 28/01/2020 14:35:36 Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 28, 2020 Share Posted January 28, 2020 I make that about 10lbs in weight. Is it possible to relocate the lipo and loose all that lead? The model's page quotes a 4S 5000mah and at the listed weight of 3.5kg that would make a lot of sense. The IC engine range would suggest (max of .60 two stroke or .90 four stroke) shooting for about 1000W on the wattmeter. 1500W will be 3d capable, or, not entirely scale. Using the rather useful prop power calculator shows your prop (14x7, 8100rpm) requires 750W of power at the prop; allowing for efficiency losses that would probably work out around 850W for the system as a whole. I would guess 14x8, or 15x6, would set things right in terms of power output, but you absolutely do need a wattmeter to tell for sure. Edited By Nigel R on 28/01/2020 14:51:04 Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 28, 2020 Share Posted January 28, 2020 **LINK** 4-max carry them as far as I can tell, most of the <£30 units look to be very very similar in terms of buttons / display / etc. Edited By Nigel R on 28/01/2020 14:50:23 Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 28, 2020 Author Share Posted January 28, 2020 Posted by Bob Cotsford on 28/01/2020 14:12:28: Sorry but your 4S battery won't cut it. You need 6S aiming for a maximum peak of 50A with a fresh battery dropping down to the 45A PatMc quotes. When playing at this sort of power level a wattmeter is essential, without it you will have real problems as you are just taking a stab in the dark and hoping nothing goes pop. A wattmeter simply plugs between the battery and ESC and gives you a direct measurement of amps, volts and you guessed it, watts. 40oz of lead? The 6S battery of around 4500mAH pushed as far forward as possible will help, but that is still a lot of lead. Have you mounted servos in the tail by any chance? Edited By Bob Cotsford on 28/01/2020 14:30:12 No servos in the tail and lipo as far forward as possible Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 28, 2020 Author Share Posted January 28, 2020 Ordered a watt meter from 4 Max, see what the findings are.👍👍 Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted January 28, 2020 Share Posted January 28, 2020 On that motor the other option would be a 15 x 8 prop on a 4s which would give 4kg static thrust at 57amps or a 15 x 10 which would give 4.7kg at 67 amps. The 14 x 7 will give around 3.2kg at 43 amps on a 4s or 6.1 kg at 82 amps on a 6s. So if you go with a 6s then you could prop down a bit, say a 13 x 6, which gives 4.7kg at 60 amps, or go with a bigger prop on the 4s, but a 6s sounds a better option and remove some of that lead in the nose. Note all the above are calculated results and should be confirmed by measuring the amps. BTW we are just restoring a Mick Reeves Hurricane of a similar size and have gone with a 5060 380kv motor with a 15 x 10 prop on a 6s setup. Should be flying this spring once our strip has dried out and had a few rolls/cuts. Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 28, 2020 Author Share Posted January 28, 2020 Sorry my mistake. It is a 580kv motor. DODO. Quote Link to comment Share on other sites More sharing options...
eflightray Posted January 29, 2020 Share Posted January 29, 2020 Some people love and trust calculations/calculators, personally I don't. I tend to rely on experience, a wattmeter, and importantly, a tacho. A wattmeter will protect the system from too high an amps draw, whether you are using a prop or a flywheel. Watts don't fly a model, likewise a flywheel don't tend to help the model fly . But a tacho showing what rpm the prop is achieving is a very good starting point, add some experience, (keeping records), will give a much better idea of what will fly a model fly well. Just from my own records, - 4Kg model, (63" Sparrow Hawk) - 14" x 7" APCe - 8300 rpm - flew the model really well, with plenty of aerobatics. So to me I know what the prop rpm needs to be. The watts drawn, (amps), is almost unimportant, it's just a safety feature. Sorry if I have stepped on a few toes, but the right prop turning the right rpm is what flies the model well. Ray. Edited By eflightray on 29/01/2020 10:18:46 Quote Link to comment Share on other sites More sharing options...
Peter Beeney Posted January 29, 2020 Share Posted January 29, 2020 Exactly so. Ray, I’ve always thought along the same lines; although I’m probably even more basic. I start with the tacho and measure the unloaded kV first to make it is what it says on the tin, generally very close but definitely not always the case. Then I can base everything else on that, relating the prop speed to the unloaded speed I can guess within reason what the current flow will be and also of course very importantly how the model will fly; that’s in conjunction to the already known wing loading, of course. Then check for any hotspots with a thermometer and verify my current flow guess with a clip on power meter; and then if necessary some juggling with prop sizes when it’s in the air. And as you say, perhaps not every one’s cup of tea, but then I’ve generally preferred coffee anyway… #ilurvemytacho PB Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 29, 2020 Author Share Posted January 29, 2020 Thanks guy's, all my other warbirds are glow and if there are enough rpm there, then of you go to the field and fly. The tacho reads 8100rpm on the 14x7 APC electric prop, on my glow engines on average about the same, and they fly great, and I think they are all slightly above the weight that it says in the manual. I have run it at full throttle for the safe length of time for the lipo not to fully discharge, until it reads 3.8v on each cell and there are no hot spots, battery just warm. If it was a glow engine running 8100rpm i would be happy. Because this is my first electric on this scale just want to be sure. Quote Link to comment Share on other sites More sharing options...
Ronos Posted January 30, 2020 Author Share Posted January 30, 2020 HI all, here are my results with a wattmeter at full throttle with a 4s 5000mAh 40-50C discharge rate.14x7 apc prop 37.5A 16 VM 0.422Ah 27.55Ap 449.0Wp 6.7 Wh could someone explain what the readings mean please. Quote Link to comment Share on other sites More sharing options...
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