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Home › ✈️Aircraft › 🚁Helicopter › e-Align › T-REX 600 › BL XL Motor "D725"

11-07-2020 04:10 PM 5 months ago

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0Post 1

maxell44

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BL XL Motor "D725"

Ok so after my last few successful summers of flying my Trex 600 with a Suppo 1000kv motor running 6S 7000mah 25c Tattu Lipos, I have decided to experiment with the stock XL 1650 BL motor with the laser etched "D725" engraved on the bottom of it (apparently this is the NEW post recall motors). It came with the chrome 10T pin gear. (Psst, I never used this motor from the start). According to the picture I found online of the motors specs, it says the motor is rated from 3s to 6s. That said, because I fly old fart style of intermediate sport flying no 3D what so ever, I endeavour to try and run a 30c 5000mah 4s lipo instead of 6s. I fly with a flat TC of 80%. I'm looking at running 1800 to 2000 rpm headspeed. I don't need insane headspeed for my style of flying. I would like to at least get (6 mins) flying time max. Anybody have thoughts....??

**I might add I use a Turnigy plush 32bit 100amp ESC**

Motor specs: (taken from another website)

●Input voltageC11.1-22.2V 3-6cell Li-Po
●Max continuous current:70A/85A(60sec)
●Max output power:Approx. 1600W/2000W(60sec)
●KV value:1650KV
●Dimension:spindle 5x65x43.3mm
●Weight:Approx. 300g Accessories:
●ALIGN standard 4mm gilt terminal x 3set(Max. current 80A

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11-07-2020 07:32 PM 5 months ago

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Rojoalfa

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Ok...

The main equation...

Rpm. Max= volts * KV * pinion/spur

Your data

Volts 22.2
Kv 1650
Pinion 10
Spur 112?

Rpm. Max= 22.2*1650*10/112

Rpm.max= 3270 rpm

Your 600E needs a power of 2 HP, 2 * 745 = 1490 watts.

So, other equation...

Power = volts * amps

1490 = 22.2 * amps

Amps= 67 amps

This is the average consumption of your 600E.

If you want to fly at 1800 rpm

Other equation...

% stick = rpm / rpm. Max * 100

Rpm 1800
Rpm.max 3270

% stick = 1800/3270*100= 55 %

So, To handle 1800 rpm, the motor will consume aprox 55% of 67 amps, 37 amp.

Your ESC, turnigy 100 amps...
With the minimum of 37 amps and a max of 67 amps, this turnigy will work.
To handle 67 amps max, your ESC is going to work aprox at 67% which is good.

My thoughts...

1. This motor will work, no problem with this pinion.
Check for high temp when flying.

2. ESC will work.
Don't like turnigy gadget!

3. Please, do your calculation to verify.

4. When flying, make some measurement to double check your calcs.

5. I am not pretending to do a calculation "precise" . It is just and approximation.
Do your things at your own risk.

This is a general calculation.
I do this to verify in a general way, my selection.

/Saludos cordiales,

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11-07-2020 07:48 PM 5 months ago

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maxell44

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http://calc.kfmconsulting.se/

https://www.runryder.com/gallery/32055/hdspeed.html

It seems I will have to stick with a 6s set up.

Thank You sir.

Good to go.

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11-07-2020 07:57 PM 5 months ago

0Post 4

Rojoalfa

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. I forgot about your lipo packs...

With 67 amps max consumption,, flying about 6 min, you will spend some energy...

Let see...

Energy = amps *1000 * flight time (min) / 60

Amps 67
Flight time 5 min

Energy = 67*1000*5/60

Energy = 5600 mAH

If you fly at 80% of lipo capacity, then...

5600 / 0.8 = 7000 mAH

You will need a lipo pack of 7000 mAH, which is what you have.

Capacity of the lipo.

Well, for 67 amps, max consumption, you will need...

67 * 1000 / 7000 = 10

You will need a minimum capacity of 10C.

You have 25C, which is good but not enough.

Some brand underestimate this C , capacity... So, take this into account.
So, give a 50% more...
25 * 1.5 = 40C

/Saludos cordiales,

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11-07-2020 08:34 PM 5 months ago

0Post 5

maxell44

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My current set up is:

Suppo 1000kv motor 6mm shaft
18T pin gear
170T main gear
100amp ESC
6s 7000mah 25c Lipo
80% flat TC
Running (x2) 7min flights per battery and I have (4) of em.
CF narrow cord 600mm blades
Radix 92mm tail blades.
GY401/9254 combo

I just thought I could try something different in a 4s configuration but as per the online calculators its not looking good. So I will stick with my 6s setup as it runs flawlessly last 3 years.

I had to try. So much for that experiment. lol.

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11-07-2020 11:38 PM 5 months ago

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Rojoalfa

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As you saw on equations, power is volts per amps.

Your 600 needs 1490 watts.

So, for 4s, 14.8 volts, you will need 1490/14.8, 100 amps!!!

To handle that power, you will need probably two 4s lipo packs in parallel and a lot of C.
Of course, a big ESC, 160 amps!
No lipo packs for your desire...

More weight, more power...

6s... Work fine!

/Saludos cordiales,

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11-07-2020 11:51 PM 5 months ago

0Post 7

Rojoalfa

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80% FTC...

Let see...

22.2 volts * 1000 rpm/volts * 18 / 170 * 0.90

Rpm. Max 2115

80% of 2115 is 1700 rpm.
Good rotor speed.

Gy401/9254, my kind of combo!

/Saludos cordiales,

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11-08-2020 12:07 AM 5 months ago

0Post 8

Rojoalfa

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BTW, 7 min flight time... Wow!

You better try to lower your flight time... Some stress for your lipo packs...
Keep record of running temperature...

5 min... It is good for your legs and lipo packs...

A trex600E should be around 600-1000 mAH per minute at 22.2 volts.

/Saludos cordiales,

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11-08-2020 11:14 PM 5 months ago

0Post 9

maxell44

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So it seems that I have a bad cell in one of my Lipo's so at the behest of my friend (Larry the R/C car guy) I have brought my flight times down to (x2) 6 min flights per battery. I was out today testing and batterys are all good. I'm down to 3.71-3.73 per cell. Well within the safe range of my Lipos. He suggested I charge em at 1.5 to 2.5 amps and I found they charge more evenly this way and all cells balance in the end. I'm using the new spectrum S1100 smart charger and it seems to be working as I expected.The Lipo with the bad cell is coming back slowly (so it seems).

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11-09-2020 01:50 AM 5 months ago

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Rojoalfa

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maxell44 I'm down to 3.71-3.73 per cell. Well within the safe range of my Lipos.

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This 3.7 volts, mean that you are using 90% of the avaliable energy on the lipo.
A lot of stress for your lipo packs.
Ok, this is probably good for new lipo packs but not for so long.

I would recommend to end your flights with 20-30% of remaining energy on the lipo packs. The voltage should be around 3.8 volts per cells.

/Saludos cordiales,

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11-09-2020 02:00 AM 5 months ago

0Post 11

maxell44

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For me running 5mins or less is unacceptable. I need at least 6mins or 7mins to get my fix. Less than 6mins in the air just doesn't seem worth the effort to even go out and fly at all. For the amount of $$ I've invested into this 600 I want my $$'s worth. Now I ran a battery tonight for 10mins total flying. The voltages were around the 3.8'ish range. I'm confused now...? Two 6mins flights 3.7'ish range....one 10min flight 3.8'ish I don't get it...?? A difference of 2mins....??

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11-09-2020 11:30 AM 5 months ago

0Post 12

Rojoalfa

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maxell44 I'm confused now...? Two 6mins flights 3.7'ish range....one 10min flight 3.8'ish I don't get it...?? A difference of 2mins....??

/
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You are not confused.

All lipo packs are not the same and you Can't compare new with old lipo packs even the same brand.

If you want more flight time, look for new lipo packs.
A second choice is to work on the Heli setup.

/Saludos cordiales,

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11-09-2020 03:49 PM 5 months ago

0Post 13

maxell44

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Hmm, what to do what to do...?? Well my set up before was using a lower pin gear (15T), but I found I wasn't getting the headspeed or FF speed I wanted. So I jumped up to the 18T gear. I didn't want to change my throttle curve. I like running 80% flat. As I understand I can keep 80% and increase HS by only changing the Pin gear without changing the throttle curve. I guess I could try a 17 or 16...? Finding em in north america with a 6mm bore is next to impossible. I had to order all my pin gears from ercmarket in Belgium cause nobody over here had anything, trust me I looked.

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11-09-2020 09:17 PM 5 months ago

0Post 14

Rojoalfa

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No that simple!

Imagine you are in the center of a triangle.

Top corner is flight time.
Right corner, manouvers.
Left corner, rpm.

The way you move, no matter to what corner, you gain something but you loose something.