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[triumphjon]

hi all , im biulding a huntsman 28 at 1/12 th scale in wood and will be installing the two propshafts as per origanal boat . i was going to install a pair of 400 brushed motors but as ive already decided to go brushless in my other fairey spear & huntsman 31 was thinking of doing the same to this model . therefore does any body know what the equivelent brushless motor would be to a speed 400 please ? jon

[nick_75au]

Speed 400  RACE 4.8v     1.2-6v     4583Kv
Speed 400    6v             2.4-7.2v     3000Kv
Speed 400   7.2v             3.6-8.4v     2278Kv

Any of the 22 mm motors in these Kv ranges would be equivalent if you use the same voltages, better efficiency can be gained by increasing the voltage and decreasing the Kv

Nick

[HS93 (RIP)]

for a fast sports boat I feel you need a much lower KV between a 1000kv  and 1800KV I have used a couple of these motors in a boat that was about 20" and it was so overpowered I had to remove them BUT they ran cool so no need for water cooling and had a good run time the motors I used where Mystery D2836-1700 kv and ran them on 7.2volts you can run them much higher and get even more power out of them.
Peter

[nick_75au]

In addition I would think that most speed 400 applications would require gearing, so repeating HS93s comments a lower Kv in the range HS93 mentions would be ideal, but direct drive and up to a 40 mm prop.

Nick

[triumphjon]

i intend to run on 7.2 volt battery packs with no more than a 35mm 3 bladed prop per motor , jon

[knoby]

I'm running a 14 inch swordsman on 1 of those mystery 1700kv motors that HS93 has shown. I run it in a 30mm 3 blade propshop prop, using 7.2 volt 4500mah nimh pack. flat out it runs for around 25 mins & the motor is barely warm when touched. I don't use water cooling for the motor or the controller. There are a couple of club 400 boats at the sailing water & it is considerably faster than these. The motor is direct drive. Only down side is the slow speed running is poor, but i don't care cos i built it to go quick !!

Cheers Glenn