YS 91 SRS RR

[mnentwig]

I got me a YS 91 SRS RR into the 700. Pure alphabet soup
Tried it for the first time at Röylä and it looks quite promising.
It's still set very rich, but apparently even so it is on par with or has even more power than the old, obsolete and discontinued YS 91 SR.

[SJo1]

as it's tuned by RR, could you tell from where it's tweaked? Carb, needles or/ and cylinder ports/ channels modified by enlarging them. Did You checked internals of the engine before took it in to use.
-Samppa

[mnentwig]

I don't know the SRS, therefore I couldn't tell.
What I noticed is the stainless steel backplate.
Anyway, after all the trouble I had and still have with the SR (with a standard OS # 8 it vibrates too badly for the V-Bar), this was just the opposite. Put it in, turn the starter => works.

[mnentwig]

OK, I must say I'm very happy with this engine.
I just can't make it work with 30 % nitro optifuel. A colder plug helps somewhat, but then there is the risk that it dies during spool-up.
I guess it would need a shim. But it runs very nicely with 20 % nitro. I'm tired of tweaking, I just want to fly.

At 1600 headspeed, fuel consumption is pretty low. Flying the .56 in the 600 on 30 % nitro wouldn't save any money, and still the 700 is a much more capable heli.
Probably we'll see lots of cheap 2nd-hand 91 SR in the "for sales" section soon.

[MJPilot]

How cheap? 

[Vispilä]

How soon? 

[mnentwig]

nice try