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View Full Version : Good gear setup for a 5400Kv motor?


Twmaster
12-18-2005, 12:20 AM
I recently got a pair of E-Flite 5400Kv brushless inrunner motors. I'd like to put one of them on my Ultimate FX which comes with a 6.6:1 gearbox and 12 x 6 propeller. The kit calls for a 4100Kv motor. Should I prop down a bit or bring the ratio up? Or can I just use it as-is?

qban_flyer
12-18-2005, 12:47 AM
I recently got a pair of E-Flite 5400Kv brushless inrunner motors. I'd like to put one of them on my Ultimate FX which comes with a 6.6:1 gearbox and 12 x 6 propeller. The kit calls for a 4100Kv motor. Should I prop down a bit or bring the ratio up? Or can I just use it as-is?

Prop down to 11X6 or smaller. You'll have to use your WhatMeter quite a bit until you get things within the correct range.:)

You're almost 7 to 1 on your reduction ratio already. I have no clue if a 9 to 1 box that will fit that motor is available. :o

MarkC
01-16-2006, 02:41 AM
You can do either or both. With a Cobri or Brute gear box you can get 7.6:1. With that ratio you may be able to use an 11-4.7 or 11-7. I`m at 6150 ft. elevation so you might not can go that big nearer sea level. An amp meter is the only way to know for sure.

MarkC

Twmaster
01-16-2006, 03:45 AM
Unfortunately I only have a Himaxx and GWS gearbox to choose from. (read that as I am not buying another gearbox)

So I still need to determine what size prop I can use. Of course you are correct in that my watt meter is my best friend for this job.

Dr Kiwi
01-16-2006, 03:52 PM
I'd try it with a 10x6 GWS HD - I don't know what the max amps are for that motor, but 15A seems about right: Here is what Motocalc says for a 10x5 APC E (and a 10x6 GWS HD will draw a bit less).

Motor: E Flite 370 5400; 5400rpm/V; 1.3A no-load; 0.02 Ohms.
Battery: Thunder Power Pro Lite 2000; 3 cells; 2000mAh @ 3.7V; 0.007 Ohms/cell.
Speed Control: Castle Creations Phoenix 25; 0.0065 Ohms; High rate.
Drive System: Himaxx; 10x5 (Pconst=1.11; Tconst=1) geared 6.6:1 (Eff=80%).
Airframe: Anything you want.
Batt Amps = 16.8
Motor Amps = 16.8
Motor Volts = 10.6
Input (W) = 178.4
Motor RPM = 55478
Prop RPM = 8406
Thrust (oz) = 30.2
PSpd (mph) = 39.8

My concern would be that on 3s the motor rpm's are over 50,000 - too much I think. That's why this motor seems to be recommended for 2s.

MarkC
01-17-2006, 12:16 AM
I have flown this motor on 3s with a GWS C-drive box at 6150 ft with a 9-7 thin prop. Had to use mucho restraint with the throttle though. With a D-drive, I`m sure the thin 10-6 would work, just don`t go throttle crazy.

MC

MountainFlyer
01-17-2006, 02:12 AM
Continuous Current is 10amps
Max Burst Current is 15amps
for the E-Flite 370 5400Kv EFLM1005

the 370 5400Kv is more aimed at a 2 cell Lipo from what ive read on it from E-Flite

rcers
01-17-2006, 03:36 PM
I can tell you all from real experience if you keep the amps down to 10 you will be just fine on 3s.

It is right at the limit, but I have one in use for over 200 flights with nary an issue. I fly at full throttle a fair bit too. I think they key is the amp draw. The guys who use 3s and push to 12-13+ amps cook them.

Mike

Dr Kiwi
01-19-2006, 02:42 AM
Trouble is that, if Motocalc is right, keeping current draw to ~10A means a 9x5 GWS HD prop or thereabouts on 6.6:1 and the motor rpms are waaay high! (57,000rpm anyone).

Motor: E Flite 370 5400; 5400rpm/V; 1.3A no-load; 0.02 Ohms.
Battery: Thunder Power Pro Lite 2000; 3 cells; 2000mAh @ 3.7V; 0.007 Ohms/cell.
Speed Control: Castle Creations Phoenix 25; 0.0065 Ohms; High rate.
Drive System: Himaxx; 9x5 (Pconst=0.95; Tconst=1) geared 6.6:1 (Eff=80%).
Airframe: Anything you want.
Motor Amps = 10.5
Motor Volts = 10.8
Input (W) = 113.7
Motor RPM = 57161
Prop RPM = 8661
Thrust (oz) = 18.3
PSpd (mph) = 41.0

Personally I think I'd stick with 2s.

Twmaster
01-19-2006, 03:00 AM
I'm wondering if I should just unload these two motors I have and get something with a bit lover kv.

rcers
01-19-2006, 05:42 PM
Personally I think I'd stick with 2s.

You do that, I have well over 200 flights with the 5400 C gearing and a 9x5 prop. Actual amps tested at 10.5 and no issues.

Sometimes actual flight experience tells you something static testing won't.

The high RPMS are just not an issue and in fact it has worked very well.

Mike

Matt Kirsch
01-19-2006, 08:17 PM
Don't be too hasty to dump those 5400Kv motors. They work fine if you drop the prop size to keep the Amps down. A friend of mine has one set up with 6.6:1 and a 10x3.8 or 10x4.7 Eflite prop on a 3S Kokam 1500. Works fine, and he flies the living daylights out of it on an Eflite Tribute.

The high RPMs are mitigated by the fact that you don't use 'em 99% of the time, but they're handy when you do need them.

If'n you could get an 8:1 ratio or even slightly higher, you could reeeeeeally get some serious 3d thrust out af that motor.

Dr Kiwi
01-20-2006, 03:21 AM
You do that, I have well over 200 flights with the 5400 C gearing and a 9x5 prop. Actual amps tested at 10.5 and no issues.

Sometimes actual flight experience tells you something static testing won't.

The high RPMS are just not an issue and in fact it has worked very well.

Mike

I'm glad to hear that. I was just erring on the side of caution 'cos most inrunners I know of are rated at 50,000rpm max. Perhaps that is, indeed, conservative. Once I (briefly) ran a little 12mm motor at over 69,000rpm and it survived!

Twmaster
02-12-2006, 04:44 PM
Thanks for all the input folks. I think I am going to keep these motors for now. I found some data on the Himaxx web site regarding their 2015-5466 sets (which seems to use the same motor spec wise) and they are claiming 11 and 12" props on the 6.6:1 GB.

watt_the?!
02-20-2006, 03:24 AM
..

If'n you could get an 8:1 ratio or even slightly higher, you could reeeeeeally get some serious 3d thrust out af that motor.


:) amen brother!...a himax 2025-4200 with a 15 inch prop!

SKYPILEIT
02-23-2006, 09:34 PM
Real powerhouse..!I've used the Castle/Mamba and Himax 2015/5400 with 6.6:1 gearing and 10X6 prop for about 140 watts safely,no overheating and it will take any 12-18 oz. park flyer verticle very fast....with the TP 1320 3 cell pack.

Twmaster
02-24-2006, 12:22 AM
Eeeeexcellent!

Twmaster
04-23-2006, 02:36 AM
Thread revisited.

Ok, I'm wondering if this is a good idea or not now. I have installed this into my airframe. (EF Park 370-5400, Himax 6.60:1 gearbox TP15A ESC) no prop yet. Connected to a 3 cell lipo and ran it for about 5 or 10 seconds just to see what direction it was turning so I can set the wiring in place. Man it got warm in the 5 to 10 seconds I ran it. I checked it is not binding at all and the gear lash looks fine.

Ideas? Or do these get warm just buy running them?

Twmaster
04-23-2006, 02:57 AM
Some data.

5400kv E-Flite Park 370, 6.6:1 Himax gearbox, 3S Vampower 1050mA lipo, TowerPro 15A ESC, APC 9x3.8SF prop.

10.8A static WOT, 117W (measured with my Astro Whatt meter), 16.8 ounces of thrust (measured with my fish scale).

Didn't get too much more testing as the flippin prop flew off the motor. (Yes I had it on tight) :eek:

Twmaster
04-23-2006, 05:04 AM
The reason the prop flew off is that the end of the motor shaft broke off! :eek:

Anyways, I posted another thread with the photo of the busted motor. :(

So, I removed the gearbox setup, installed a Himax 2808-980 outrunner with a 10x4.7SF APC prop and the same battery and ESC.

12.6A, 10.4V, 127W, 16.74OZ

And it's nice and quiet!

:D

qban_flyer
04-23-2006, 03:04 PM
The reason the prop flew off is that the end of the motor shaft broke off! :eek:

Anyways, I posted another thread with the photo of the busted motor. :(

So, I removed the gearbox setup, installed a Himax 2808-980 outrunner with a 10x4.7SF APC prop and the same battery and ESC.

12.6A, 10.4V, 127W, 16.74OZ

And it's nice and quiet!

:DBad motor, bad motor, bad motor. Link to that other thread so that we can view the bad motor? :confused:

Twmaster
04-23-2006, 03:11 PM
OK. Here:

http://www.wattflyer.com/forums/showthread.php?p=65276

qban_flyer
04-23-2006, 03:18 PM
That shaft looks wicked! I hope the rest of their inrunners are better!