Stratus Gear Ratio & Pipe

[Aviation addict]

Guys, Can anyone confirm the correct Gear Ratio when purchasing a Stratus Kit to go with an OS91 SZ-H with P/P & Regulator?

Also, which pipe are people using with this set-up SB17 or SB18?

[If there is a choice of gearing dependant on the kind of flying you're going to do I have to warn you that it's all mild 3D at present, just Stationary Rolls/Flips & Inverted. Don't think I'll need a headspeed of 2100 for a little while!]

What's the normal recommended Stratus headspeed by the way (1600 - 1850 ish ?) I'm just a Raptor man at present so genuinely don't have a clue (about XCell's that is)!

[DavidH]

I would suggest 8.18 for the OS 91 SZH. From talking to pilots that are using the SZ motor, it like to turn a higher rpm than the Cspec motor. Most of the pilots that were using the Cspec and turning it 1750-1850. And now they have the SZ and are turning it 1850-1950 on the rotor head and 8.18 ratio.

I would use the SB 18 with the SZ. I have also heard a rumor that an SB 19 might be in the making for the SZ motor. Don't know if there is any truth to it. But I would think it would have a little more volume than the SB 18.

David

[Aviation addict]

Perfect - Thanks once again David.

[ka-man]

I used with O.S SZH(no pump)
8.18G.R
1900rpm :mrgreen:

[Turbo Dave]

I run a YS91 with SB18
8.18
1930 headspeed
which gives the same engine RPM as 1900@8.27 that i used to run in my Raptor
The Stratus is very fast being about a Kilo lighter :mrgreen: