How do these motors compare power wise?

[kfxguy]

I'm on the fence on which motor I want to get. Long story short, lehner 2250 1972kv on 6s ran 96mph on 6s in my 32" cat. I'm building another one but this time I'm not using a lehner. More of a budget build I guess you could say. Everything thing else being the same (Esc, prop etc) I was hoping to get close to what the lehner was doing. I was considering a tp power 4060 2040kv, going a little higher kv because the lehner rates theirs a little different, with a load on it. How much load? I'm not sure but I've read that the unloaded kv is 10% higher which would be roughly 2169kv. The tp would be "close enough" if I'm thinking right. Also my thought process is maybe the 4 pole may be able to keep up with the 2 pole because the rpm realm is mid to low 40k's. I would think the lehner would grossly outshine it at a higher rpm, but that's just my theory based on the limited experience I've had with them. I'd rather get a neu but they don't offer a kv that will suit my intended use. If I get a custom wind, by the time I pay for that I might as well order another lehner. So what are you guys thoughts? Would the tp keep up with it close enough or am I wasting my time? I've only run one tp motor and it did pretty well. Think it's worth a shot?

[NativePaul]

Lehners rate their KV at the point of maximum efficiency, which with your 2250/6 on 6s is 94.5% at 187A.

While I have never used one or heard about anyone testing their efficiency, I would doubt the TP is close to Lehner in that regard, If the TP was 85% efficient which would be OK for a mid range budget motor, to get the same RPM at the prop as the Lehner you would need 2320kv, it would consume 12% more amps and produce 3 times more heat.

If all you are interested in is speed and you weren't pushing the Lehner to its limits then a TP could be just as fast, but losing that much more energy to heat it will reach its failure point a lot quicker, you could use a motor with more mass than the Lehner's 560g to slow the heat rise rate down and the bigger can would have more surface area to dissipate a bit more heat.

[kfxguy]

Lehners rate their KV at the point of maximum efficiency, which with your 2250/6 on 6s is 94.5% at 187A.

While I have never used one or heard about anyone testing their efficiency, I would doubt the TP is close to Lehner in that regard, If the TP was 85% efficient which would be OK for a mid range budget motor, to get the same RPM at the prop as the Lehner you would need 2320kv, it would consume 12% more amps and produce 3 times more heat.

If all you are interested in is speed and you weren't pushing the Lehner to its limits then a TP could be just as fast, but losing that much more energy to heat it will reach its failure point a lot quicker, you could use a motor with more mass than the Lehner's 560g to slow the heat rise rate down and the bigger can would have more surface area to dissipate a bit more heat.

Good info. Supposedly the tp are rated at 90% efficiency. How true that is, I don't know. Now. The neu's are rated at 90% too iirc. I have ran this motor and a neu 1521 in the same hull with the same prop and they were almost exactly the same speed. The neu kv was 1860 and the tp was 1870kv. Then I have another thought in the back of my head....my mono, 91mph with a lehner 2260 and 84.7mph (batts were run down too) with a neu 1527. Lehner kv 1677 and neu 1500kv. Both on the same batts. The props were different but the lehner could not turn the prop like the 1527 could. So. Just some thoughts. One is definitely a fair comparison, the other one is hard to say, but still worth considering and mentioning. I sound like I'm trying to talk myself into trying a tp don't I? Lol. I guess I could always sell it if it don't work out.

[NativePaul]

IF it was 90% the figures would be 2190kv, 5% more amps, 85% more heat.

[TRUCKPULL]

Travis

What about the NEU 1527 1D 2300KV 8mm shaft
It would give you a little more RPM
You could use a little smaller Dia. prop for more stability, or same prop for more speed.

This motor on 6S has been used for SAW runs many times.

Larry

[kfxguy]

Travis

What about the NEU 1527 1D 2300KV 8mm shaft
It would give you a little more RPM
You could use a little smaller Dia. prop for more stability, or same prop for more speed.

This motor on 6S has been used for SAW runs many times.

Larry

Problem is the length. Maybe I need to mock up a hull and see how it turns out. 2300kv on 6s is a little higher than I like tho. 6s and 2200 is kind of my ceiling but that's not that much difference. 48,840rpm vs 51,060

[TRUCKPULL]

Problem is the length. Maybe I need to mock up a hull and see how it turns out. 2300kv on 6s is a little higher than I like tho. 6s and 2200 is kind of my ceiling but that's not that much difference. 48,840rpm vs 51,060

50,000 prop RPM is about right for SAW's is it not???

Larry

[kfxguy]

So let's do this.... How does a 1527 vs a 4070 tp compare? Both same length and diameter....2200kv tp and 2300kv neu.... The neu is double the price too. I have a 4060 that I just took apart and it's nicely made....very close to a neu...

[srislash]

Do it Trav, as you know I have been running TP's for quite awhile now. How many runs on that pair of 12s 4050's all loaded up for 100mph and 43,000rpm? Quite a number and still going strong.
You have me double thinking my HPR build with the LMT's. It seems to me the LMT's are away more sensitive to radical prop change. I could go from my 47mm props to 50mm and the TP's would pull them. Faster? Who knows but how about that jump with LMT?

[srislash]

And since the numbers are up, the motors are 1020kv, batts are Dinogy 12s 3300mah and the real shaft rpm is 42,500'ish. At some point I had batts under load at 3.65 volts per cell.

[kfxguy]

Do it Trav, as you know I have been running TP's for quite awhile now. How many runs on that pair of 12s 4050's all loaded up for 100mph and 43,000rpm? Quite a number and still going strong.
You have me double thinking my HPR build with the LMT's. It seems to me the LMT's are away more sensitive to radical prop change. I could go from my 47mm props to 50mm and the TP's would pull them. Faster? Who knows but how about that jump with LMT?

Lmt's are VERY sensitive to prop change an voltage. In my limited experience with them I've found:

If you go up on voltage (at a certain point) the boat doesn't go much faster unless you go down in prop. I had that happen in both boats. With the neu in both boats when you add voltage it picks up a lot per cell. It would pick up 17mph in my Rivercat going from 6s to 7s

[TRUCKPULL]

If you go with the TP or maybe even the NEU to be pushing the 50,000 RPM mark
you may want to look at the Boca Ceramic Hybrid bearings from OSE

Larry

[kfxguy]

And since the numbers are up, the motors are 1020kv, batts are Dinogy 12s 3300mah and the real shaft rpm is 42,500'ish. At some point I had batts under load at 3.65 volts per cell.

What do you think....

4060 2040kv or
4070 2050kv or
4070 2200kv? I do like that the 4070 has an 8mm shaft but at 100mm long it's gonna be hard to fit that in a 32" cat...it's doable tho. Just not sure if the slight power difference is worth it.

[kfxguy]

If you go with the TP or maybe even the NEU to be pushing the 50,000 RPM mark
you may want to look at the Boca Ceramic Hybrid bearings from OSE

Larry

Thx. I usually do change my bearings to ceramic. Didn't on the lehner because I don't have tool to take them apart.

[TRUCKPULL]

TP 4070 2200KV is a 2Y
TP 4070 2050KV is a 4D

Y winds are normally less AMP's
D winds are AMP hogs with lots of torque.

Larry