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Futaba-RC . A Main Hobbies . Boca Bearings

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Engines Plugs Mufflers Fuel > Gear ratio for a YS 80?
 
 
yzlvr
Heliman
Location: Los Angeles

Is anyone using a YS 80? What ratio are you running? TIA
10-17-2001 Over year old.
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freestyle
Veteran
Location: Redmond WA USA

Funny you should ask, we were just talking about this in #rcheli chat room earlier today.

One guy said he liked 9:1 with a 1700 RPM head speed.

Another guy said no, no, you've GOT to run 8.2:1 with 1850-1900 RPM.

It was kind of funny watching one guy try to tell the other guy that he was going to blow up his motor, because if you do the math, you'll see that they're BOTH running the engine at about 15,300 RPM. That's probably not a conincidence. It seems that they booth decided that the engine runs really well at around 15,300 RPM.

Go to this web site:

http://www.natew.com/rcheli/frames.....GenericGearing

Type 15,300 in the "Motor speed" box.
Type your preferred head speed in the "Rotor speed" box.
Try different gear sizes until you find a good match.

I hope this is helpful.
10-17-2001 Over year old.
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Augusto
rrAdvertiser
Location: San Diego, CA

A bit higher than the one needed for the OS-91.
For instance if you use a YS-80 on a Freya you definitely need the 11 tooth pinion but if you're using the OS-9 you can use the 12 tooth pinion. It also deppends on how fast you like your head speed. In my case I usually run a very high head speed and then the 12 tooth pinion is right about right where I like it so you should first decide what your head speed is and then find out what gear ratio puts your engine a little above the max power band so that when you start bogging it it will fall to the max power area.

Avant Aurora Ultimate
10-17-2001 Over year old.
 
 
freestyle
Veteran
Location: Redmond WA USA

What engine RPM do you use with the YS 80, Cole? The two guys I talked to were both right around 15300, but more data points would be nice. For all I know they're right on the edge of the powerband, might actually be better at 14700 or 16000 or something.
10-17-2001 Over year old.
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Maxx
Key Veteran
Location: Shreveport Louisana

From everything I can asertain; the O.S.91 has a max RPM/HP of 16000 and the YS 80 is at 18000. So running a gear ratio of 9.0 to 9.4 will result in a M/R RPM of 1770-1700 with the O.S. and 2000-1900 for the YS. So the YS in my Futura SE with a final drive ratio of 9.39 would end up having to turn 16440 RPM to run a 1750 head speed. What I would like to see is a blade manufacture build a 700mm blade with a 70mm chord...THEN you could use a lower M/R RPM and rely on the massive torque these engines produce for the eye-popping vertical and impressive 3D now seen at the upper (1800-2000) end of the M/R RPM scale! I know that when I put wide chord blades on my Conquest/OS50 combo I could run 1650RPM instead of the 2000RPM I was running with a 55mm chordx600mm blade. The drop in engine and M/R RPM made for a much quieter heli that will do every trick in the book without a hint of bogging! A side benefit to a wider chord blade is the amount of pitch range ( cyclic and collective) required is not as great... This engine data is from the Cyberheli web site. I mixed up the YS/OS data...I hate when Mondays come on Wendsdays! Maxx
10-17-2001 Over year old.
 
 
z11355
rrMaster
Location: 10000 is enough time wasted.

Pls doublecheck those numbers. The YS has a datasheet max of 17K and the OS has a max of 16K RPM.

Most all of the people I know running the YS (dont know anyone w/ the OS) are running it at about 15.5-16K
10-18-2001 Over year old.
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Maxx
Key Veteran
Location: Shreveport Louisana

Z11355, I edited my post to reflect the correct numbers for the correct engine. Thanks for catching my blatent stupidity...that's the down side to the World Wide Web; if I do or say something dumb in person, only the people around me know I've Boobed...when typing in a World Wide Forum an "unintended mis-quote" lets the entire D**n Planet know I have the IQ of Plant Life...(sigh). Onward, ever Onward...Maxx
10-18-2001 Over year old.
 
 
Augusto
rrAdvertiser
Location: San Diego, CA

I'm runing 17400 for the YS and 16200 for the OS.

Avant Aurora Ultimate
10-18-2001 Over year old.
 
 
freestyle
Veteran
Location: Redmond WA USA

Wow... If you're running the YS at 17400 with an 11 tooth pinion, and the OS at 16200 with a 12 tooth, your rotor speeds are be around 2050 RPM. Is that what you meant by 'very high head speed?'
10-18-2001 Over year old.
HOMEPAGE  
 
 
Augusto
rrAdvertiser
Location: San Diego, CA

Yup that's my GV-1 stunt 3 setting. I use it mostly when I do sustained piroueting flips. Otherwise I run it at 1875 rpm for the rest of it. I used to worry about it a bit but I've been flying with this settings for quite a while now. Also once I measured other guys runing >2500 head speeds at the drag races I stopped worring about it.

Avant Aurora Ultimate
10-18-2001 Over year old.
 
 
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Engines Plugs Mufflers Fuel > Gear ratio for a YS 80?
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