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Propdrive 5060 380kv


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Wonder if anyone can help here. I have the NTM propdrive 5060 with a 100 ESC and using a 6 cell 5000 30 c batteries. This is on the Great planes Sequence . I am unable to get more than 1000 watts unless I use an 18 x 10 propeller which gives 1400 watts .I am unsure about this as . The recommended for this motor is 17x8 or 17x10 . I have been told than I am over propping . I have not maidened the plane yet and do not want to fry anything . Can anyone give me some help .

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Hi Linda,

1400W equates to about 64 amps which is well within the limitations of both your esc and motor (max 90A according to the spec), so I'd have thought it should be fine. Looking at the reviews on HobbyKing somebody tested it with 20'' props on 6S and thought it might get hot on a 20x10 but a 20x8 would be ok, so 18x10 should be good. The smaller props are probably meant for 8S batteries, which the motor is specced to take.

John.

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Thanks Tim,What prop do you suggest I try ? The reason I want to stick with 6 s is that I am using them on my other models and have plenty. The manufacturer recommended 6 s on the Sequence with the Rimfire 120 but this is now discontinued so I went for as close a match as I could get .

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As far as frying anything goes, what matters is the current it's drawing.

1400W on 6S works out at about 63A depending on the state of the battery. Hobbyking give a max current of 90A for the motor, so 63A is comfortably below the limit. If it takes an 18x10 to get that, then that is what it takes!

Hobbyking recommend batteries between 6S and 8S for the motor, and I guess that the "recommended" 17x8 or 17x10 is for 8S. If you were to try your 18x10 on 8S instead of 6S then it would draw a lot more than 63A - quite likely over 90A, and then you'd see the "magic smoke"...

[Edit] And once again. others (JM!) prove they can type faster than me! smile

Edited By John Privett on 02/05/2018 20:45:57

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Looking at the comments on HobbyKing I see people are using 17 x 8 with an 8 cell Lipo and up to 20 x 8 on 6 cell.

Whilst I tend to take some of these HK postings with a large pinch of salt it would nevertheless suggest that 18 x 10 is probably in the right ballpark.

How many amps are being drawn with the 18 x 10? HK say the motor is rated at 90 amps max. so as long as you aren't exceeding this figure all should be well.

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Thanks John , That is good to know ?The readings on my watt meter show 64 /65 amps 1400 watts . The motor or ESC doesn't get hot altho 'because I am running on the ground and am not doing this for long is a not a true reflection of what will happen in the air. I guess I will have to see if the set up is capable . Many thanks Linda

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Completely agree with comments so far, as long as measured current is within specs then the prop matters not.

Two things spring to mind, I have measured the KV of some motors from HK and they haven't been as stated

The other thing is the voltage of one 6S pack even when only pulling 30A can sag more than another, so this could also account for some differences. ie quality of the pack.

Cheers

Danny

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I think quoted KV figures are at best useful guides. Probably they're reasonably accurate when the motor is running unloaded. As soon as a prop is fitted then the rpm/volt tends to reduce. On 6S (say 22v) this motor will theoretically spin at 22 x 380 = 8360 rpm but I suspect on your 18x10 it will be less than that.

In any case the thing to be concerned about is the current draw and it seems you are well inside the limits there as everyone says. However, with a battery capacity of 5AH it might be as well to make the test flight a short one and check how much energy has been used. I use a 6S 4.5AH in my Mew Gull and I consume about 60% IIRC after about 7 minutes of fairly gentle flying even though my maximum current (as indicated via telemetry) is around 65 amps. That's with a nominal kv of 420 rpm/v and a 16x8 prop.

I don't think you're smoke or frying territory I hope you have a successful maiden.

Geoff

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"I think quoted KV figures are at best useful guides. Probably they're reasonably accurate when the motor is running unloaded"

Well yes, but kv is pretty much defined as the unloaded figure, I thought?

That, combined with some knowledge of the motor characteristics, enable the prediction tools like PropCalc to do their job.

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Are we sure this is a 380kV motor, as there is also a 270 kV version of the propdrive 5060?

I ask because I run a 365kV motor (Hacker A50 16s) on 6s with a 17x8 prop and regularly get 1200w in the air even with my old bateries on a cold day - I have seen well over 1400w with newer batteries.

Dick

 

Edited By Dickw on 03/05/2018 10:24:04

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Thanks everyone for your help with this one .I am going to try my 17 x 10 and then 18x10 and go from there . Yes Dick the motor is 380kv . I did some more tests this morning and here are the results . 17x8 E prop 991 Watts 43 amps .......17x 10 prop1180 Watts 52 amps ......18 x 10 E prop 1526 watts 65 amps .

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Thanks everyone for your help with this one .I am going to try my 17 x 10 and then 18x10 and go from there . Yes Dick the motor is 380kv . I did some more tests this morning and here are the results . 17x8 E prop 991 Watts 43 amps .......17x 10 prop1180 Watts 52 amps ......18 x 10 E prop 1526 watts 65 amps .

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Something seems odd as 991 watts at 43 amps suggest 23 volts – which is reasonable for a 6s pack on that load.

On the other hand, I have just checked a random data log for my Pitts fitted with 365kV motor, 17x8E prop on 6s and came up with 1198 watts at 53 amps (=22.6v - during a flight so battery part discharged).

Still, you have what you have so larger props to make use of it seems the way to go, and shouldn’t be a problem.

Dick

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Hi Linda

There's a huge difference between the 380kv of the Propdrive motor and the 450kv of the Rimfire. On the same GP recommended 17x8 prop, to get the same shaft rpm (and hence the same pitch speed you'll need for the equivalent aerobatic performance) from the 560-380 as the Rimfire 120, you can't avoid increasing cell count beyond 6S. Otherwise, if staying with 6S, increasing prop pitch and diameter is the only option.

Whilst kv figures can be unreliable, they're the only spec we have to go on, and should be close enough for decent estimations to be made. Assuming that the 380 and 450 are approximately true, then the 380 has only 84% of the pitch speed on 6S and the same prop. So you'll need to increase the pitch from GP's recommended 8in to 9.5 theoretical, and 10in in practice. So your 18x10 looks like being a good choice at present. If you're worried about excessive current draw, simply trim the prop tips in 1/8in steps (ie reducing overall prop dia by 1/4in each snip) until you achieve the current you want, remembering to re-balance after each trim. Whilst current draw will drop, the rpm and hence pitch speed won't change all that much.

I know it's a bit late, but the nearest equivalent motor to the Rimfire I found in the HK range which should handle the power you want is the Turnigy Aerodrive SK3-5055-430kv and even that is somewhat low on kv, but still a lot closer than the Propdrive's 380.

Hope this helps, and good luck with your maiden.

Gordon

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Thanks Gordon ,That is a very comprehensive explanation .I think I'll try the 18x 10 first and after a short flight check the battery consumption. If things are not as I would like it's probably better to change the motor than invest in a number of 4 cell batteries. Hopefully things will work out well.

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Well ,the maiden went very well .I used the 18x10 and after a 3minute flight landed and checked battery consumption . I had over 60% left. So second flight on new battery was 6mins and still30% left so more than happy at the moment. Verticals weren't fantastic but on this set up more than adequate for a reasonable flight and well capable of a few routines . Thanks to everyone for their advice .😊

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