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Revolution Models . CarbonXtreme . Midland Helicopters

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e-MS Composit Hornet > New Digital micro servo Futaba S3154
 
 
Micro-Maniac
Elite Veteran
Location: Pasco,Washington Formerly: Captain Chaos

The pinion is 25t - The 2208/20 1820kv produces about 2500 rpm head speed with some drag calculated in - The 2212/20 1950kv would produce about 2700 rpm head speed with some drag but much more power - Maybe too much.
12-19-2006 Over year old.
 
 
helikopeter
Heliman
Location: stockholm , sweden

Hi Razmo

Well

What can I say about it?, I really like my heli , itīs stable as it can be , very solid in the hover, but I want more power :-)

according to Ms compositīs review, their ms 300/20 motor, gives 1820 rpm per volt , but my rotor is running over 2000rpm , I havenīt tached it yet , but it sounds like it , I am using MS compositīs own ESC , i MEAN THE ONE THAT CAME WITH THE MOTOR , and I am running it on normal mode, not in governor mode, because in that mode it gives VERY low RPMS , and my gas curve in idle 2 is 90, 90, 90, 80,75,80,90,90,90 , I donīt use 100% , because for some reason, in that value the motor doesnīt rev up as much as it should ( I still wonder why) , if you wonder about my TX, itīs a futaba 12z , and my RX is also futaba pcm micro ( I donīt remember the model) 6 channels

Best regards

Peter
12-19-2006 Over year old.
 
 
Micro-Maniac
Elite Veteran
Location: Pasco,Washington Formerly: Captain Chaos

The MS-116 ESC is rated for 8A cont/12A spike according to the documentation -

The 2208/20 pulls about that same current 8A-12A - This combo with 25t pinion probably doesn't produce more than 2300 actual rpm head speed.
12-19-2006 Over year old.
 
 
helikopeter
Heliman
Location: stockholm , sweden

axi 2212/12

Well yes, I had already considdered the fact that I might need an ESC that can handle the amps , and this motor draws more power than the MS 300 , so I am going to need a battery that can also give me some more juice, I was thinking about a evo 20 3s 1500mah , I have one on my MS ecureuil , it can handle up to 30 A continous and up to 45A short bursts , but the problem is that it doesnīt fit under the hood , so I will need to put in the old place, it is under the main body , but it will shurely affect my CG.

Peter
12-19-2006 Over year old.
 
 
helikopeter
Heliman
Location: stockholm , sweden

I am thinking about using a jeti ESC that can handle up to 20A , I have one somewhere in my workshop , the only thing is that it doesnīt have soft start , but it might be up to the job.
12-19-2006 Over year old.
 
 
Micro-Maniac
Elite Veteran
Location: Pasco,Washington Formerly: Captain Chaos

Well looking at the specs of the 2212/20 shows it efficiently operates at 6A-12A - So you might get away with it using the equipement you have -

With the 25t pinion and 82% drag coefficient it would spin about a 2400 head speed plus added power and torque over the 2208/20 - That's the part I don't know how to calculate is the power and effect of different size motors.
12-19-2006 Over year old.
 
 
DarkHorse1
Senior Heliman
Location: Gloucester UK

> I donīt use 100% , because for some reason, in that value the
> motor doesnīt rev up as much as it should ( I still wonder why)
Could be the Tx endpoint is above the 100% on the ESC, mine is at max MS-116 ESC throttle around 95% with 100% Tx endpoint.

> thinking about a evo 20 3s 1500mah
124g!!! Stop, Thunder Power 3x1320mAh Prolites at 85g are still the best option today for the weight in this bird.

My 2208/20 on 3s 180T/25T was 2800 rpm with fresh 3s pack at 0š pitch, typically 2600 rpm hover fading to 2400 rpm flat (regular throttle curve like 100, 90, 85, 90, 100). A 370g performs well for the first 7 mins and slows up for another 5 mins depending how hard you fly initially (can cruise fly for 15 mins). 11.1v x 11.3A = 133 watts max but a bit boggy.

Sounds like the heli is over 370g AUW on 3s1500mAh packs.

The jury is still out as to the next setup to choose after Axi 2208/20 on 3s starts to weight above 370g.

- 3s Axi 2212/12 on near stock gearing with higher Amp draw, probably less efficient at hover power levels. Simple 3s BEC but requires a larger Amp ESC. 180T/25T I estimate 3000 rpm at zero pitch, typically ~2800 rpm.

- 4s 1380 rpm/v motor on stock gearing, same ESC and bearing rpm stress. More efficient lower Amps with higher voltage. A MaxIR has reported 14v x 14A = ~195w spikes .

- 4s Axi 2208/20 motor with reduced gear ratio (3/4) like 180T/19T. More efficient lower Amps with higher voltage (less heat). High motor rpm may have ESC timing issues. I am still yet to dial and prove the performance out of my X-3D-XL 180T/20T, awaiting new blades after an incident the other day . When will it ever end...

Check this Axi 2212/12 MaxIR video on 3s 110T/14T gear ratio. Pulls 13š on flat 100% throttle curve. Wow! For more info read on from this post here.


> That's the part I don't know how to calculate
Guess work based on observation (guess ). Seems 90% is a better efficiency multiplier for typical mid pack RPMs, otherwise the numbers reflect fresh 12.xV low load RPMs.
12-19-2006 Over year old.
HOMEPAGE  
 
 
Micro-Maniac
Elite Veteran
Location: Pasco,Washington Formerly: Captain Chaos

I knew DH would chime in with the true grit.

I looked on the AXI website and found they recommend the 2212/12 1950kv with 30A ESC for 450g helis - The 2208/20 1820kv with 12A-18A ESC for 340g helis -

I think I'll stick with my 2208/20 for now as I'm already using the smallest possible pinion with my Duzi Axi-Set.
12-19-2006 Over year old.
 
 
Razmo
Key Veteran
Location: Chicago

helikopeter,

Well, you just heard from a couple of the more experienced Hornet guys that I'm familar with and I would agree with them. Have you weighed your bird?

"Linens and Things" sell electronic scales for between 30 and 70 dollars. I went for the cheaper model because I found it was more accurate.

Raz
12-20-2006 Over year old.
 
 
Razmo
Key Veteran
Location: Chicago

This is completely off topic but I thought some of you guys might find it interesting....Lipoly and Brushless Technology

http://www.hybridcar.com/news/in-th...conomy-qed.html

Raz
12-21-2006 Over year old.
 
 
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e-MS Composit Hornet > New Digital micro servo Futaba S3154
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