Headspeed for 800

[woodsta888]

Managed to codge together a 2nd 800 heli in the Align Trekker DFC. Wanted smething different to fly that my E820 performance (395KV) wise so opted for the 850MX 490KV Dominator. I have swapped out the standard gearing for the delrin gears rated for this motor in the 800 as suggested. When I go to the Headspeed calculator I reach the max HS for 800 sized blades at only 75% (2100rpm). I have a 160A YGE with freewheel and I have followed the recommended gearing for motor & heli. Should 75% be my max? JUst wonder why they recommend a motor upgrade that maxes out at 75% of it's max rating.Any help to get this straight in my head would be appreciated.

YGE 160A
850MX 490KV
112T main
12T pinion
12S 40C

Thanks in advance

[Mutley]

I can confirm it is supposed to be 112\12 for the gearing - i am supposed to run this as well. However i run existing gearing at the moment and a 520kv.

I am using a 120yep, with the Scorpion 520kv Ultimate variants in a NickMaxwell and Rave versions. But everythings getting a little toasty but i dont think i'm anywhere near the predicted 2200+ headspeeds and using a low % - this means i'm working things too hard to keep the headspeed down.

One thing you could try is the 550 pinions, they are not quoted as fitment parts but you can use 10T pinions upwards but you will need the KDE adjustable motormount, by doing this you can run a 90% curve and around the 17-1800 headspeed with better efficiency.

[woodsta888]

Hi Mutley,

Thanks.

I have read over on helifreak a 'sticky' under their YGE section that the optimum range for a YGE when using the internal governor (which I am) is 70-80% and you shouldnt run a curve greater than 85%. So that would mean that 75% is correct for me for the max headspeed and max throttle %.

I have a YEP 180A on the E820 and have successfully run that at flat curves from 60%-85% where the motor and ESC come down cool. In fact the YEP has never come down hot barely even warm though I always run freewheel.

[Mutley]

Me too and this is how i know the ESC is being worked hard, im also fairly confident the YEP\YGE are very robust, theres a video on youtube of a guy running the 50CC rotormax motor on the 120 until he checked the logs and realised it was over 150A but it held it which is confidence at least.

I'm playing around with gearing, i dont want a high headspeed but i also know the motors i'm running are animals compared to what i actually need.