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HelicopterMiniature Aircraft Whiplash & Fury 55 › Fury 60/YS 61 ST2 Headspeed
02-06-2006 09:29 AM  12 years agoPost 1
RC Rotortek


North Yorkshire - England

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Tried this question in the Engines forum but no luck!

Does anyone know where the sweet spot lies with the YS 61 ST2 in terms of peak power output?

I have a Fury Extreme but running 9.3:1 ratio (YS61), a Hatori 90 size muffler (Hatori #996), MAH G2 690mm Blades with CP 15%. I've not run this model for months and made a few changes including dropping out my TJ Pro temporarily after fitting a different gyro since flying it last. I found today that if I put the headspeed at around 1850 to 1900 rpm (17205 to 17670 engine RPM), that the engine sounds as though it starts to hunt and this starts to violently kick the tail from side to side in time with the engine hunting sound. I tried adjusting my needles but this made no difference.

I dropped my Idleup 1 and 2 back to 1760 rpm head speed (16368 engine RPM) and the model again seems settled. Can't see any vibration issues, the model sits like it is on glass when settled and it seems punchy enough too in terms of power. I run my Stratus with YS 91 at 1760 rpm headspeed and it hauls like freight train, but I was under the impression that the 60's run higher headspeeds normally.

The muffler is slightly larger than the 60 size, but this muffler seems to develop better power. My old Zimmerman 60 muffler seemed to 'strangle' the engine somewhat.

Anyone have any previous experience with a similar scenario or does anyone know what is the peak band for ENGINE RPM for the YS 61 ST2 and ball park headspeed for a 9.3:1 60 size model using this engine?

Work sucks!!

02-06-2006 01:49 PM  12 years agoPost 2

rrKey Veteran

Long Island, NY

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Fury Expert
I run mine in the 1750 - 1780 range.

Good Judgement comes from Experience. Great Judgement comes from Bad Experience.

02-06-2006 02:34 PM  12 years agoPost 3

rrElite Veteran

Tallahassee, Florida US

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We try and keep the same headspeed, no matter what motor we are running, we just gear it differently. A YS 91 in a Fury may use 8.36 while a YS 61 would use 9.3 but both would turn 1800rpm at the rotor but the motors would be at different rpms, the 91 at 15000 and the 61 at 16700.

On a dog sled team, if you're not the lead dog, the view never changes.

02-06-2006 07:01 PM  12 years agoPost 4



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normal 1750 idle 1 1850 for mine with ys 80 but ran the same with 61 st2
using a gv1

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HelicopterMiniature Aircraft Whiplash & Fury 55 › Fury 60/YS 61 ST2 Headspeed
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