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Thunder Power RC . Mikado Modellhubschrauber . Futaba-RC

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Tools and Field Equipment > Eagle Tree logger & motor RPM sensor
 
 
Screwhead
Heliman
Location: Tucson Arizona USA

My Posts This: Topic  Forum		Hello I'm interested in using the Eagle Tree data logger with its motor RPM sensor to monitor the mainblade RPM of my 500 electric heli. This brushless motor sensor outputs the RPM of the motor, but NOT the RPM of the main rotor RPM. How do we know the actual real world rotor RPM from this device? Do we simply convert the motor RPM multiplied by the gear ratio to get the headspeed RPM? This device has been recommended by some of you at this forum, and I am considering a purchase, therefore I'm trying to learn about the system before ordering. Thank you.
11-06-2009 10:29 PM
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SunFunFlyer
Veteran
Location: Carol Stream, IL

My Posts This: Topic  Forum		If I remember correctly, the software will do the math and report the headspeed. You supply the gear ratio.
11-06-2009 10:32 PM
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Screwhead
Heliman
Location: Tucson Arizona USA

My Posts This: Topic  Forum		Ok, thank you, SunFunFlyer.
11-09-2009 07:38 PM
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JEEPWORLD2002
Key Veteran
Location: BLUEBELL PA USA

My Posts This: Topic  Forum		you have to enter the gear ratio info and u can see both motor rpm and rotor rpm. usually 10:1 on the 500 well with my gearing it is

Trex600n Trex500 Mikado LoGo5003d// Hacker, CastleCreations,Ys 50, JR 7703d/8900, Radix
11-09-2009 07:58 PM
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Screwhead
Heliman
Location: Tucson Arizona USA

My Posts This: Topic  Forum		For Eagle Tree data logger, they have three different sensors available directly or indirectly to measure the mainblade RPMs. You all are referring to the brushless motor RPM sensor, not the optical or magnetic RPM sensor, correct? The online reviews and the comments here said the brushless motor RPM sensor is most recommended among the three available sensors if I want to read the headspeed RPM.
11-09-2009 10:06 PM
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SunFunFlyer
Veteran
Location: Carol Stream, IL

My Posts This: Topic  Forum		That's what I'm referring to.
11-09-2009 10:22 PM
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Screwhead
Heliman
Location: Tucson Arizona USA

My Posts This: Topic  Forum		Thank you much, JEEPWORLD2002 and SunFunFlyer.
11-10-2009 04:17 PM
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2atlo8
Veteran
Location: Cedar Park, TX -- USA

My Posts This: Topic  Forum		For the brushless rpm sensor, you have to input both the gear ratio and the pole count for your motor. The software will calculate the headspeed and plot that out for you.

2atlo8
11-10-2009 05:27 PM
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Screwhead
Heliman
Location: Tucson Arizona USA

My Posts This: Topic  Forum		Hi 2atlo8, do I calculate the "pole count" of the motor depending how it's been setup (like a gear ratio), or it's something fixed on a motor that I could just find out in a document? I hope it's not gonna be too complicated for me because I don't know much. The setup is HK3026-1000kv Scorpion motor, Master 48-0- heli ESC, Castlecreations BEC for my 500 size heli, flying with 2 packages of 3s1p 2200mah.
11-10-2009 08:47 PM
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Screwhead
Heliman
Location: Tucson Arizona USA

My Posts This: Topic  Forum		Does the "pole count" of brushless motor refer to the "number of magnetic poles"? Then it says 8 at the manufacture's motor specs site.

http://www.innov8tivedesigns.com/pr...products_id=340

Thank you.
11-10-2009 09:04 PM
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2atlo8
Veteran
Location: Cedar Park, TX -- USA

My Posts This: Topic  Forum		Screwhead,

The number of poles is part of the motor design. It should say in the paperwork how many poles it has, but your motor has 8 poles per this reference:
http://www.readyheli.com/Scorpion_B...k-3026-1000.htm

You can also count the number of magnets, but that is difficult with some motors. The Eagletree needs this because it senses a "blip" from each pole as the motor rotates. Based on the number of blips per second it computes the motor rpm. Then it uses the gear ratio to calculate the headspeed from the motor rpm. I have used one for years and it works great.

2atlo8
11-10-2009 09:11 PM
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Screwhead
Heliman
Location: Tucson Arizona USA

My Posts This: Topic  Forum		2atlo8, I understood. I have never used a tachometer to measure the rotor RPM, and have been looking around for a device. I like the idea of real time RPM measurement by the Eagle Tree data logger and I probably get it for Xmas. It sounds straight forward than a 2-person operation using an optical tach. Thanks again.
11-10-2009 10:51 PM
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2atlo8
Veteran
Location: Cedar Park, TX -- USA

My Posts This: Topic  Forum		Get one...you'll like it. Gives great insight into not only your headspeed during manuevers, but also current draw, and how strongly your battery voltage holds up during high current demands.

By the way, with a l000kv motor, are you using 8S?

2atlo8
11-10-2009 11:07 PM
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Screwhead
Heliman
Location: Tucson Arizona USA

My Posts This: Topic  Forum		2atlo8, I'm running a 6s for this, two packs of 3s1p wired up. It's great to know my motor can handle an 8S according to you. I don't know why a 1000kv motor is used for this 500 heli. The heli was setup by Jimboflies at this forum (great guy) because I didn't know much about the setup. He's very knowledgeable so I assume there were reasons why he used a 1000kv motor, but I took what he had setup up for me. He's calibrated the headspeed RPM and everything else then, so I didn't need to adjust anything in the summer of 2008 when I got his heli. Ideally I want/need to be able to setup a heli from scratch, so now 'm trying to do things on my own scratching head. I'll get the data logger with the brushless RPM sensor. Thank you.
11-10-2009 11:59 PM
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2atlo8
Veteran
Location: Cedar Park, TX -- USA

My Posts This: Topic  Forum		Screwhead,

The stock Trex 500 motor has a kv of 1600 and is intended for 6S. If you go to the ReadyHeli headspeed calculator (http://www.readyheli.com/Online_Hea...ulator_s/81.htm) and plug in your numbers it will show that your headspeed is going to be less than 2000rpm at 100% throttle, 16T pinion, and no governor. That is VERY slow for this heli. You should be looking for something in the 2600-2800 range. The hot fliers go even higher.

You can fix this by replacing the motor with something with a kv of around 1600. (Stock motor, Scorpion 1600, Z-Power Z20-1470, etc.) Or you can use your current motor with 8S (two 4S in series). But you can only do the 8S if you have an esc that can handle 8S.

2atlo8
11-11-2009 03:49 AM
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2atlo8
Veteran
Location: Cedar Park, TX -- USA

My Posts This: Topic  Forum		Screwhead,

Put what I last posted on hold. I looked at your profile, and then I noticed you never said "Trex" 500, you just said 500. I don't know what your gear ratio is in the QJ500 in your profile, so what I said about your headspeed is probably incorrect. My numbers are correct for a Trex 500, but it appears that is not what you are dealing with.

2atlo8
11-11-2009 03:54 AM
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Screwhead
Heliman
Location: Tucson Arizona USA

My Posts This: Topic  Forum		Hi 2atlo8, thanks much for your input. Yes my motor appears to have 8 poles I see. Yeah it's an EP8EX by Quick of Japan. It's a good heli, very well built. Jimboflies (in this forum) set it up for me in a tamed manner because I'm rather a beginner. I'm guessing it's much lower than 2500RPM if not lower than 2000RPM. He has said before this heli wants 2500+ RPM for hard flying, which I don't do. Anyhow I'm still learning and the learning continues after getting the eagle tree data logger. It's nice to know the motor can handle 8S with an appropriate ESC, but I doubt if I'll need an 8S setup any time soon. The current 6S setup spins the rotor fast and scares me. I can't imagine what I'd get with an 8S. I wouldn't say I'm "flying" a heli. I'm trying to just lift off the ground and hover barely. My wife laughs at me. Happy flying.
11-11-2009 05:28 PM
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