Saito FA91 S
 

I picked up this engine new a month or so ago, I have almost one gallon of fuel through it so far. Using Powermaster 15% heli fuel, stock glow plug, and APC 14x6 prop I'm seeing about 10000 RPM max. Adjusted for flight I'll probably set it for about 9700 RPM. I'm getting a pretty good idle at around 2000 RPM. I've gotten it to idle around 1800 RPM but it sounds like it's on the verge of cutting out.

Anyone else running a similar engine/prop combination, what are you seeing?

-Kris

RE: Saito FA91 S
 

Kris, Sounds like your doing everything about right. An 1800 RPM idle is sort of low, I haven't been able to get that low an idle with the stock plug normally. I set mine for a 2000-2100 RPM idle and the planes will not roll on the short grass where I fly. When the glow plug goes get an OS F plug. I use the APC 14X6 and 14X7[special order item normally] on my Saito 91's. Your top end RPM is about the same as I get on the two 91's I'm currently using.
Fred B

RE: Saito FA91 S
 

Hi Fred,

I already got a couple OS F plugs to replace the stock plug when it goes bad. I'll take some measurements before and after the OS F plug to see if they really are as good as everyone says. The 1800 RPM idle wasn't exactly reliable, I think 2000-2100 as you suggest is more realistic.

Kris

RE: Saito FA91 S
 

Hi Chris.
Very similar to my figures, 10200 13x8 APC, mind you my favorite prop for this motor in a 63in 80's sport/patern model is a Bolly 12.5x8 giving 10700, fuel is 5%nitro,8%syn,2%castor.
Cheers.