RunRyder - Freya/OS91

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HIROBO Freya - Sceadu - Shuttle > Freya/OS91

Aleheli
Heliman
Location: Brazil and USA

I read a lot of subjects on the OS 91 and YS 80 about gear ratio to be used in Freya.
On YS 80 I talked with Todd and according to him the best would be 95 for 11.
But I also have the 91 and nor I imagine which the best gear ratio to be used, I have the options of 95:11, 93:11, 95:12 and 93:12.; which would be the best using a rotorhead speed to 1800 rpm. I will be use for 3D flight.
I thank in advance to the answers.
Alexandre Marconi.
Brazil

12-11-2001 Over year old.

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JSaleska
Senior Heliman
Location: Navarre FL

Gear Ratios

For the Freya or any other combo you just need to do some calculations to find the best gear ratio for your desired headspeed.

For example

95 Main -- 11 Pinion = 8.64
95 main -- 12 pinion = 7.91

93 Main -- 11 Pinion = 8.45
93 Main -- 12 Pinion = 7.75

The formula is ::: Main x Pinion = Gear Ratio

Now once you have the gear ratio here is how you define engine speed to rotor speed

Gear Ratio x Desired Headspeed = Engine Speed
7.91 x 1850 = 14634
8.64 x 1850 = 15984
8.45 x 1850 = 15633
7.75 x 1850 = 14338

Or you can do
Engine Speed / Gear ratio = Head speed
15300 / 7.91 = 1934

The Rated max HP of the OS 91 falls at 15300 rpms -- with max at 16000

I really like the 95 main - 12 Pinion setup on my Freya, and I usually run my rotorhead at 1750 unless I really want to tear up the sky. When I need the extra power I kick her into IDLE Up 2 which is 1850 on the governor and rip the freakin head off. hehehe

Grab a calculator and find out what works best for you.

Jon sends....

12-12-2001 Over year old.

HOMEPAGE

Aleheli
Heliman
Location: Brazil and USA

Freya/OS91

Jon thanks for your help, i will try the 95:12
Alex

12-12-2001 Over year old.

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vetrider
Elite Veteran
Location: Daleville, AL (Ft.Rucker)

JSaleska

Just noticed your first formula is wrong but your figures are right

The formula is ::: Main x Pinion = Gear Ratio should be Main/Pinion= Gear Ratio. Nice work on showing it all.

Thanks

Nolan Manley
RREMODELS, KBDDintl, Magnum Fuel
Stratus, ODIN, Knight3D, ATOM 500, TREX 700N.

12-12-2001 Over year old.

JSaleska
Senior Heliman
Location: Navarre FL

WHAT AN IDIOT

I'm of course refering to myself.

Sorry guys about the misinformation. Vetrider is of cours correct, and it's Main / Pinion equal gear ratio.

Jon sends....

12-12-2001 Over year old.

HOMEPAGE

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HIROBO Freya - Sceadu - Shuttle > Freya/OS91

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