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shauntot · 08-20-2007, 09:43 AM

chaps, just picked up an Eagle Tree FDR. Don't know which logger to choose for measuring the headspeed for my 600. Keen to measure it as I've just picked up a Z30A-1110kv for it today turning a 16t pinion.

Which one is more accurate?

The Brushless Motor RPM Sensor or the Optical RPM Sensor?

http://www.eagletreesystems.com/MicroPower/micro.htm

thanks in advance!

cbdane · 08-20-2007, 11:20 AM

Quote:

Originally Posted by shauntot

chaps, just picked up an Eagle Tree FDR. Don't know which logger to choose for measuring the headspeed for my 600. Keen to measure it as I've just picked up a Z30A-1110kv for it today turning a 16t pinion.

Which one is more accurate?

The Brushless Motor RPM Sensor or the Optical RPM Sensor?

http://www.eagletreesystems.com/MicroPower/micro.htm

thanks in advance!

I use the brushless sensor. Very easy to install. Works great.

Mercuriell · 08-20-2007, 04:00 PM

I've also been very pleased with the brushless sensor (hot glued direct onto the datalogger and shortened its lead) and have no worries about its accuracy

cudaboy_71 · 08-20-2007, 04:16 PM

they're both equally accurate. the brushless motor sensor is a LOT easier to set up. in fact you can just push a straight pin through the wire on the sensor and through a wire on the motor and you're done.

the optical one needs a black/white reference on a spinning part. so, you'll end up either painting one of your rotating parts or fabbing up a colored ring to mount somewhere on a spinning shaft..then mounting the sensor so it can read it.

bullaculla · 08-20-2007, 04:24 PM

I still haven't mounted my optical sensor...
what a pain!

shauntot · 08-20-2007, 07:45 PM

ok then..brushless sensor it is!

thanks guys!

th3tick · 08-20-2007, 10:07 PM

I tried all three on my 600

The optical sensor didn't like my sharpie on the main gear idea. For the Hall effects sensor, I couldn't find a good spot for the sensor itself, but the magnet glued into the gear just fine. I later found the magnet stuck to my battery box. I wonder when that came loose!

The brushless sensor is simple to install, but I hated resoldering it when I changed ESCs or motors. I ended up taking a pair of connectors, soldered a piece of bare wire in between, then the wire from the brushless sensor to it. I formed it bent at 60 degrees, which made heatshrinking it a pain, but it worked out Now it's just an inline plug between the ESC and the motor. Let me know if want to see a picture of what I came up with.

John

cudaboy_71 · 08-20-2007, 10:15 PM

Quote:

The brushless sensor is simple to install, but I hated resoldering it when I changed ESCs or motors.

no need for any of that. just take a straight pin and stick it through the red lead from the sensor and through one of the 3 motor wires from your motor or esc. not very clean. but, i don't run the eagle tree all the time. i'm usually just after a quick reading after a change....a flight or two max. so, a temporary install is perfect...especially with 4 electrics i want to monitor.

th3tick · 08-20-2007, 10:24 PM

Quote:

Originally Posted by cudaboy_71

no need for any of that. just take a straight pin and stick it through the red lead from the sensor and through one of the 3 motor wires from your motor or esc. not very clean. but, i don't run the eagle tree all the time. i'm usually just after a quick reading after a change....a flight or two max. so, a temporary install is perfect...especially with 4 electrics i want to monitor.

Two electrics, two Micro Power recorders here. I want to be able to check after each flight, so mine are semi-permanently installed.

John

cudaboy_71 · 08-20-2007, 10:29 PM

i'm just saying i can check after every flight, too. moving it from one heli to the other takes less time than plugging in another lipo.

but, there's nothing wrong with running multiple loggers. i just need one. thought i'd point out the reasoning. that's all.

shauntot · 08-20-2007, 11:17 PM

any pics guys?

bullaculla · 08-21-2007, 01:29 AM

I think i'm gonna buy the skytach. I used a friends at the field the other day and it was awesome. but hard to do it solo :mrgreen:

shauntot · 08-21-2007, 06:58 AM

agree, skytach is still the best, but you have a point, it'd be impossible to use alone

anyway i think the best would be to have a skytach and someone tach the heli, and run a FDR along with the flight to verify

Tasteless · 08-21-2007, 07:03 AM

For a single person job.
I used a 1/2-1 degree pitch down on a throttle curve end point to end point.
The negative is to make sure it does not take off and provides a little load, and I don't ever do this in any sort of wind.
This gives a reasonable speed indication under a little load.
Much easier to do this properly with a second person doing the tach.

Regards
T

n55w131 · 08-21-2007, 03:56 PM

The brushless motor sensor is not as accurate (You can ask eagletree why and they can explain it to you, it is a result of resolution/time) as the optical or hall effect rpm sensor for measuring rotor head speed. The brushless sensor uses a derived head speed, calculated from motor rpm / gear ratio. The optical or magnetic (hall effect) are a more accurate reading as they are mounted directly on the main gear / shaft and are reading true head speed.

I have all three, I can show the differences. The optical and the magnetics are within 2% of each other. At the same time the brushless can be more than 10% off.

thefig781 · 08-22-2007, 09:38 PM

Quote:

Originally Posted by n55w131

The brushless motor sensor is not as accurate (You can ask eagletree why and they can explain it to you, it is a result of resolution/time) as the optical or hall effect rpm sensor for measuring rotor head speed. The brushless sensor uses a derived head speed, calculated from motor rpm / gear ratio. The optical or magnetic (hall effect) are a more accurate reading as they are mounted directly on the main gear / shaft and are reading true head speed.

I have all three, I can show the differences. The optical and the magnetics are within 2% of each other. At the same time the brushless can be more than 10% off.

...my eagle tree using a brushless rpm sensor was spot on with the reading from a sky-tach. So I guess
that is close enough for me.

Jim

philo · 08-23-2007, 02:17 AM

Ive had the FDR for over a year on my Eraptor and av tried all 3 methods. The only one i had that worked for me was the brushless sensor. As for the acuracy ive found that if you program in the correct gearing ratio it is suprisingly accurate i tached my head speed 6 months ago and set my TC at 1800 RPM suprised to see that the headspeed displayed was 1802 on the FDR. Bear in mind that the resolution on the optical tach is + - 100 rpm on the display (please confirm if im wrong) dats my 2 cent hope it helps

Sandy · 08-23-2007, 04:18 PM

I too have had to change the gear ratio to match the tacked HS, but once that is set it is consistenly accurate..

08-20-2007, 09:43 AM	#1 (permalink)
shauntot My HF Map location Join Date: May 2006	headspeed measurement using Eagle Tree chaps, just picked up an Eagle Tree FDR. Don't know which logger to choose for measuring the headspeed for my 600. Keen to measure it as I've just picked up a Z30A-1110kv for it today turning a 16t pinion. Which one is more accurate? The Brushless Motor RPM Sensor or the Optical RPM Sensor? http://www.eagletreesystems.com/MicroPower/micro.htm thanks in advance!

08-20-2007, 04:00 PM	#3 (permalink)
Mercuriell HF Support Join Date: Sep 2006	I've also been very pleased with the brushless sensor (hot glued direct onto the datalogger and shortened its lead) and have no worries about its accuracy __________________ John

08-20-2007, 04:16 PM	#4 (permalink)
cudaboy_71 Registered Users My HF Map location Join Date: Jun 2005	they're both equally accurate. the brushless motor sensor is a LOT easier to set up. in fact you can just push a straight pin through the wire on the sensor and through a wire on the motor and you're done. the optical one needs a black/white reference on a spinning part. so, you'll end up either painting one of your rotating parts or fabbing up a colored ring to mount somewhere on a spinning shaft..then mounting the sensor so it can read it. __________________ ˙ʇı ʞɐǝɹq 'ǝʞoɹq ʇ,uıɐ ʇı ɟı

08-20-2007, 04:24 PM	#5 (permalink)
bullaculla Registered Users Join Date: Nov 2006	I still haven't mounted my optical sensor... what a pain! __________________ T-Rex 600 HFE-stretched to 700, 10s, Tango 45-08, Jazz 55, JR7703D/S8900G, DJ Vegh nose cam mount. T-Rex 600 HFX-stretched to 700, 10s, Orbit 30-12, Jazz 55, GY611/S9256, Askman 360 mount. JR X9303.

08-20-2007, 10:07 PM	#7 (permalink)
th3tick Registered Users Join Date: Mar 2007	I tried all three on my 600 The optical sensor didn't like my sharpie on the main gear idea. For the Hall effects sensor, I couldn't find a good spot for the sensor itself, but the magnet glued into the gear just fine. I later found the magnet stuck to my battery box. I wonder when that came loose! The brushless sensor is simple to install, but I hated resoldering it when I changed ESCs or motors. I ended up taking a pair of connectors, soldered a piece of bare wire in between, then the wire from the brushless sensor to it. I formed it bent at 60 degrees, which made heatshrinking it a pain, but it worked out Now it's just an inline plug between the ESC and the motor. Let me know if want to see a picture of what I came up with. John __________________ Logo 600 3D V-Bar, Jazz 55-10-32, Tango 45-7, 0.7/13T, BLS451/BLS251, JR R921, Maniac623 Logo 500 3D V-Bar, Jive 100+LV, Scorpion HK-4020-1100, 0.7/15T, S9452/S9256, AR7000, RT560 T-Rex 600 CF, Jazz 80-6-18, Neu 1515/2.5D/F/H, 11T, S9451, ds760/S9254, AR7000, Radix600 T-Rex 500 CF, stock ESC/motor/rotors, 13T, HS-5245MG, ds760/S9254, JR R921

08-20-2007, 07:45 PM	#6 (permalink)
shauntot Thread Starter My HF Map location Join Date: May 2006	ok then..brushless sensor it is! thanks guys!

08-20-2007, 10:29 PM	#10 (permalink)
cudaboy_71 Registered Users My HF Map location Join Date: Jun 2005	i'm just saying i can check after every flight, too. moving it from one heli to the other takes less time than plugging in another lipo. but, there's nothing wrong with running multiple loggers. i just need one. thought i'd point out the reasoning. that's all. __________________ ˙ʇı ʞɐǝɹq 'ǝʞoɹq ʇ,uıɐ ʇı ɟı

08-20-2007, 11:17 PM	#11 (permalink)
shauntot Thread Starter My HF Map location Join Date: May 2006	any pics guys?

08-21-2007, 01:29 AM	#12 (permalink)
bullaculla Registered Users Join Date: Nov 2006	I think i'm gonna buy the skytach. I used a friends at the field the other day and it was awesome. but hard to do it solo :mrgreen: __________________ T-Rex 600 HFE-stretched to 700, 10s, Tango 45-08, Jazz 55, JR7703D/S8900G, DJ Vegh nose cam mount. T-Rex 600 HFX-stretched to 700, 10s, Orbit 30-12, Jazz 55, GY611/S9256, Askman 360 mount. JR X9303.

08-21-2007, 06:58 AM	#13 (permalink)
shauntot Thread Starter My HF Map location Join Date: May 2006	agree, skytach is still the best, but you have a point, it'd be impossible to use alone anyway i think the best would be to have a skytach and someone tach the heli, and run a FDR along with the flight to verify

08-21-2007, 07:03 AM	#14 (permalink)
Tasteless Registered Users My HF Map location Join Date: May 2006	For a single person job. I used a 1/2-1 degree pitch down on a throttle curve end point to end point. The negative is to make sure it does not take off and provides a little load, and I don't ever do this in any sort of wind. This gives a reasonable speed indication under a little load. Much easier to do this properly with a second person doing the tach. Regards T __________________ Trex 600 Al, BL650, MK4044 16th,0.7.6mm, T&L 600mm Blades, Outrage 5000, 401+9254 and 3xHS-5475 Trex 450XL Blinged BL35X JGF 500 14tooth GY401-Futaba 3154, Fp Evo 25 2170 3 x HS65MG R770

08-21-2007, 03:56 PM	#15 (permalink)
n55w131 Join Date: May 2007	Head Speed accuracy. The brushless motor sensor is not as accurate (You can ask eagletree why and they can explain it to you, it is a result of resolution/time) as the optical or hall effect rpm sensor for measuring rotor head speed. The brushless sensor uses a derived head speed, calculated from motor rpm / gear ratio. The optical or magnetic (hall effect) are a more accurate reading as they are mounted directly on the main gear / shaft and are reading true head speed. I have all three, I can show the differences. The optical and the magnetics are within 2% of each other. At the same time the brushless can be more than 10% off.

08-23-2007, 02:17 AM	#17 (permalink)
philo Registered Users My HF Map location Join Date: Sep 2006	Ive had the FDR for over a year on my Eraptor and av tried all 3 methods. The only one i had that worked for me was the brushless sensor. As for the acuracy ive found that if you program in the correct gearing ratio it is suprisingly accurate i tached my head speed 6 months ago and set my TC at 1800 RPM suprised to see that the headspeed displayed was 1802 on the FDR. Bear in mind that the resolution on the optical tach is + - 100 rpm on the display (please confirm if im wrong) dats my 2 cent hope it helps

08-23-2007, 04:18 PM	#18 (permalink)
Sandy Registered Users My HF Map location Join Date: Dec 2005	I too have had to change the gear ratio to match the tacked HS, but once that is set it is consistenly accurate.. __________________ TDRx2 Mikado 600SE

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