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HomeAircraftHelicopterVario Sky Fox - Benzin - Evolution - Xtreme › Head Speed still too low on my XLV-E
10-13-2010 06:36 PM  8 years agoPost 1
hazchem88

rrVeteran

W.Mids UK

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not sure if my XLV is underpowered or just still got the wrong gear ration.

First I was using the wrong pulley (my calculations say use 21T)
So I used a bigger one,22T, to try and get more headspeed.

I get to about 700rpm, at 0degrees, with 100% throttle.
Which is still too low.

Did I get my calculations correct?

I would be really happy if someone could review my setup;

12S (50v) Lipos,
80Amp CC ESC (80HV)
21T (and now tried 22T) pulley.
Axi Motor p/n 534514, 225KV

Although head speed is too low, it really bogs and headspead drops a lot when I start to apply a little pitch.

Please let me know what you think

many thanks!!

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10-13-2010 09:21 PM  8 years agoPost 2
doorman

rrProfessor

Sherwood, Arkansas

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ESC Settings????
You might have something set wrong in the ESC... You will need the proper number of poles for the motor (I looked and could not find a spec) which should be with the motor paperwork or just count the magnets....set the timing to Outrunner and if you are using the governor mode you will need the proper number of cells and the gear ratio..... (main gear divided by the pinion xx/22)

As for you calculations, this might help:

12s x 3.7 = 44.4 volts

44.4 volts x 225kv = 9990rpm x .90 = 8991 rpm at the pinion
(we are deducting 10% for actual effeciency and 5-10% is common now with the new equipment we have)

Then you need the gear ratio (the Main Gear divided by the pinion..
An example would be 97/22 would equal 4.41:1

Divide the RPM by the gear ratio to get you APPROX head speed...

8991/4.41 = 2038 hs rpm (I know I am off on the actual gear ratio, but this might help you get into the right area..)

Good Luck, Stan

AMA 2918-Team Spin Blades,,Castle Creations, Unique Aircraft

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10-14-2010 10:32 AM  8 years agoPost 3
hazchem88

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W.Mids UK

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I rechecked ESC settings, I think they are OK.

Probably my calculations were too optimistic.
I've lost the original calc's but I'm pretty sure I didn't factor in efficiency (which is 93% max.)

I redid calculations factoring in efficiency, and I need more like 26T not 21T.
Will order a new pulley and give that a go

# of poles; do I count the number of copper windings (there are 12)?

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10-14-2010 02:59 PM  8 years agoPost 4
doorman

rrProfessor

Sherwood, Arkansas

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Number of Poles
For the number of poles you would count the number of magnets around the can.....and if you have this info wrong, it will not let the motor come up to proper running speed....
On the Castle site go to the ESC links and choose you ESC and then run a demo mode on it and you can make all the changes and read each explanation and once that is done, you should be able to change the numbers in the program to match what you have or in the demo you can play with different gearing and HS to see if you are in the proper range.....
Good Luck..... Stan

What is the count on your main gear..... and what hs are you trying to reach?? If you still have a problem, let me know and I will run the info and compare it to yours once you supply the above two answers....

AMA 2918-Team Spin Blades,,Castle Creations, Unique Aircraft

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10-14-2010 03:49 PM  8 years agoPost 5
hazchem88

rrVeteran

W.Mids UK

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the CC ESC does not have an option to put pole number in. I think it works it out itself.

Gearing is a little more complex on an XLV.

Main gear is 70T, this drives a 20T. The 20T is on a shaft shared by 83T pulley, which drives the motor Pulley (which I work out should be 26T) to achieve approx 810rpm on the head

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10-14-2010 04:24 PM  8 years agoPost 6
doorman

rrProfessor

Sherwood, Arkansas

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Pole Count???
I just went into the Castlelink program (version 3.25) and looked for a 80HV... could not find one, but opened a Phoneix 80 and was able to find the info on the pole count...
If you go to the throttle page and set the first item to helicopter, then the throttle type to Governor mode and under settings for governor mode, use set RPM, you should then get to the page that asks you for the number of batteries,then on the next page it asks for KV and then pole count and gearing info....
I am not really certain how to get the actual final gear ratio when there are two steps either, but with the info that you gave me, I am thinking that the final gearing is 7.65:1 (BUT please confirm this with you kit supplier or manufacture to be sure)
On the set up that you have, with the info added as I have it, it looks as if you should be able to pull 830 to 1100 rpm with your set up.... again though PLEAS CONFIRM your final gear ratio...
But do look further into the ESC set up.... it really sounds like something is not correct there.....
Let us know what you find.... and good luck.... Stan

AMA 2918-Team Spin Blades,,Castle Creations, Unique Aircraft

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10-14-2010 04:36 PM  8 years agoPost 7
hazchem88

rrVeteran

W.Mids UK

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I am useing simple governor, so you don't need to enter gear ratios.
I just use a tacho instead.

when there are 2 pairs of gears, like the vario, you work out the 2 ratios for the pairs, then multiply the 2 for a final ratio

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