Eagle Tree Hurricane Setup

[Wazzer]

Hey Guys

Any one here running an Eagle Tree eLogger on their Hurricane?

I want to check on the Brushless Motor RPM sensor set up as i am not getting realistic RPM readings.
I should be getting about 18000 rpm showing but its more like 25000+rpm
And as you would expect the calculated indicated Head speed is also out.

I am using the eLogger with both the Old 850KV motor and the newer 1100KV motor.

My questions are this

I have the 850 motor set for 10 poles and a overall gear ration of 8.99 (as per manual)

I am using all stock gears with a 13 tooth pinion on both motors.

and i have the new 1100 motor set with 8 poles and the same gear ratio

When i put the numbers into the Ready Heli or ezfly calcs the overall gear ratio can be calculated closer to 12.05:1

An input will be most appreciated

many thanks

Ben

[mjdee14]

I have just started using it and only have about 4 flights so far.

Did you calibrate using 10.37 for the gear ratio?

Don't know where you got the 8.99 but according the Bob Finless the ratio is

main gear/auto gear X secondary gear/pinion = ratio

61/19 X 41/13 = 10.37

try using that and see if your #'s come out better.

Mike

[taz]

im using the Optical RPM Sensor with my v3 elogger and i have just painted half of the inside of my main gear white as it needs half white and half black for the optical sensor to see it and it reads the head speed
works a treat

[Wazzer]

I got that overall gear ratio from the cover of the Hurricane manual!!

Have tried the 10.37 as you suggested but i still get gretly inflated RPMs and Headspeed readings Does this work for you?
Are you getting readings close to what you expected?

I was also wondering if the no of poles for the motor is wrong
what motor are you running?
what are you entering for the number of poles for your motor

Thanks for the info

ben

[Wazzer]

I also have the Optical sensor so i may try that as well.

i was hoping to get the Brushless sensor workinig well as its very easy to swap between heli's (i am using the elogger on 5 different heli's)

thanks for the input

ben

[mjdee14]

I have ben using the stock Gaui 890 kv motor with a 15 t pinion.....geting about 20,000 rpms on the motor and 19 - 2100 on the head...it seems reasonable to me.

Also using 3500 polys and 515 cf blades.

I also have the opitcal sensor and would like to hook that up some time to see how acurate the brushles is.

i also had to use both wires on the brushless as one would not work alone.

i just swapped to a Z20 980 KV motor and only have 1 flight, but the lipos dies so I don't really have good info.

I really like the Eagletree and I get good numbers on all the other parameters.

[bugdozer]

What I did on my T-Rex 450 and what I'm planning to do on my Huri, as soon as I can get my hands on a wired type V3, I run the Logger in 'Live Mode' while clocking the head with an optical tach. Then I tweak the ratio in the logger until it exactly matches the true head speed. I also calibrate the voltage and current draw at the same time.

Edit: This is with the brushless sensor.

[ukgroucho]

WHY are folks using the optical tach? It really is hard work compared with using the brushless motor sensor... I thought the V3 Eagletrees had this built in?

I just pull apart one of my motor connection bullets, strip a little wire from one of the brushless RPM wires and poke it into the female side of the motor connector and push the male in. Makes a nice connection and is easy to remove if I want to redeploy the Eagletree (V2). So long as you get the right pole count and gear ratio it's a breeze....

[bugdozer]

WHY are folks using the optical tach? It really is hard work compared with using the brushless motor sensor... I thought the V3 Eagletrees had this built in?

Because the EagleTree is not accurate until you calibrate it. It can be off by a couple hundred RPM's if you just enter the calculated ratio. The optical tach is a one-time deal unless you change your motor or gearing. I have a chunk of foam that I stick the tach in and set under the rotor. Only takes a minuet of two.

[BL]

This is the same problem that I faced 2 months ago.

I also heard that the 850kv stock motor is 10 pole and the HS that I got was 2200rpm with 14T/42T.

Tested with 12 pole and everything sound reasonable to me.

So for your case,
No of pole = 12
Gear ratio = 10.37

[Madedon]

i just swapped to a Z20 980 KV motor and only have 1 flight, but the lipos dies so I don't really have good info.

I really like the Eagletree and I get good numbers on all the other parameters.


I just swap to Z20 980 KV motor what parameters you are using?

I have changed my gear to RevCo which gives 61/23*68/19=9.4919 ratio and set the poles to 8. Is this correct?

When referring to poles we count the number of magnets and not the number of coils in the motor?

[mjdee14]

I just swap to Z20 980 KV motor what parameters you are using?

I have changed my gear to RevCo which gives 61/23*68/19=9.4919 ratio and set the poles to 8. Is this correct?

When referring to poles we count the number of magnets and not the number of coils in the motor?

The ratio sounds about right...on one page i think they also used a .9 multiplier since you won't have 100% efficinecy...and YES 8 is the number of poles...meaning N & S...the Gaui stock motor has 20 magnets...but only 10 poles.

[taz]

WHY are folks using the optical tach? It really is hard work compared with using the brushless motor sensor... I thought the V3 Eagletrees had this built in?

I just pull apart one of my motor connection bullets, strip a little wire from one of the brushless RPM wires and poke it into the female side of the motor connector and push the male in. Makes a nice connection and is easy to remove if I want to redeploy the Eagletree (V2). So long as you get the right pole count and gear ratio it's a breeze....

because the optical tach is very accuate and isnt that what we want ????????????????????????

[Phoinix]

I agree. I installed the optical tach on my hurricane and it's pretty much what i want. Accurate, reliable and it needs no extra modifications to fit it on the fuselage.

[worldofmaya]

Where to you use your optical tach? I heard you should use it on your second gear and paint it half white?
-Klaus

[Phoinix]

Hey Klaus!

You can use optical tach anywhere you get 1:1 readout. So to speak, on all rotating parts mounted on your main rotor shaft. I have marked my main gear with a white dot and placed the optical tach in a position where it can read that dot. I don't belive it can be doner any simpler. Wires, that seem to be loose are quite tight in their place and there is no way that those wires running in between the two gears could get a grab on them.


http://i97.photobucket.com/albums/l236/BlenderPilot/Show%20and%20tell/Modeli/Hurricane%20550%20Build/DSC04712.jpg


This hurricane is wired to its bits:
Optical RPM
Air temperature, battery temperature, motor temperature
Eagletree V3 (currently not installed)
Power panel
Altimeter and Airspeed indicator (currently not installed)
Current draw sensor

[worldofmaya]

Great!!! Thanks a lot!
-Klaus

[Wazzer]

Hey Phoinix

Ithought you had to paint at least half of the gear white for the optical Tach to work as opposed to just a white dot??

If its just a white dot then its a piece of cake!

I do like the idea of the brushless sensor though as it is easier to swap from model to model. I fly with 2 other heli flyers with 5 heli's between us so its nice to record all 5.

Will try out the White dot and Optical tach for comparison.

Cheers

Ben

[Phoinix]

I marked only a 5 mm diameter white dot and it works for me. A bigger dot could improve readings, but i had no problem up till now. If it works for me, i can't see why it wouldn't work for all.

[ukgroucho]

because the optical tach is very accuate and isnt that what we want ????????????????????????

I'm not sure I understand the concern over the accuracy of the brushless monitor. Maybe I missed something in the documentation.
As I understand it it is counting pulses to the motor. With the correct pole count it measures and accurate motor RPM - and with the correct gear ratio, that translates to an 'accurate' inferred measure of headspeed.

In terms of 'fitting' the BL motor monitor is by far the easiest IMO. No additional bits to mount on the frame - just stick the end of the BL monitor wire into one of the motor plug connectors (bullets). It's so small it just gets pinched into the bullet, no solder require, easy to move to another heli or plane.
Also, because the EagleTree sits up front (by the battery connectors) it avoids additional spagheti running back behind moving gears... whilst that stuff can be done nicely it is still prone to bits getting dragged into gears if you crash.

Anyway.. I use the BL motor monitor and am happy that it gets me good numbers.

[bugdozer]

I'm not sure I understand the concern over the accuracy of the brushless monitor. Maybe I missed something in the documentation.
As I understand it it is counting pulses to the motor. With the correct pole count it measures and accurate motor RPM - and with the correct gear ratio, that translates to an 'accurate' inferred measure of headspeed.

In terms of 'fitting' the BL motor monitor is by far the easiest IMO. No additional bits to mount on the frame - just stick the end of the BL monitor wire into one of the motor plug connectors (bullets). It's so small it just gets pinched into the bullet, no solder require, easy to move to another heli or plane.
Also, because the EagleTree sits up front (by the battery connectors) it avoids additional spagheti running back behind moving gears... whilst that stuff can be done nicely it is still prone to bits getting dragged into gears if you crash.

Anyway.. I use the BL motor monitor and am happy that it gets me good numbers.

When I threw Optical Tech out there, I meant I used an external optical tach to calibrate the brushless pickup for the eLogger, using live mode. Just entering the ratio will not get you accurate readings and you can be off by a couple hundred RPM. Once the brushless pickup is calibrated, you don't need to do it again unless you change your motor or gearing.

[Phoinix]

I'll be getting a brushless sensor in a few days, so i'll be able to compare both.

[bstock]

I agree with UK - I plan on getting an Eagletree (birthday coming up) - and the brushless sensor seems to make the most sense - in only that I want to move it around to other helis.

I do like the idea of calibrating the readings to a hand held optical tach, that makes sense (I didn't even realize it could be done) - just need to get the guy at the club who has one... to make sure he brings his out to the field for this.

[Phoinix]

One thing i like aout optical tach and dislike about brushless sensor is my autorotation practice and testing. I can't read RPM when i hit throttle hold. It reads rotor rpm not calculated motor rpm into rotor rpm, that's the difference that wins with me.

[ukgroucho]

That's a fair point.. if i could autorotate nicely I'd agree with you but that's something I need to work on :)