Chancho

Gents,

I need your help. I have a Saito FA-100 that is going in for service and I'm planning on putting an new FA-125 in it's place. The FA-100 was turning a 13x11 more than just fine and I'd like similar or better results in the speed department.

The FA-125 advertizes 15x7 - 17x6. I'd like to run a 14x11,12, etc... Does anyone have any thoughts or experience in regards to using the FA-125 for speed?

* Plane weight is 7.5 lbs.
* I'm running %15 Nitro, all synthetic and 3.5 oz of Castor oil in each gallon.

Thanks in advance for the help and Best Regards,

Phil Green

proptop

My Feedback: (8)

I was thinking maybe a 14x12...
APC also has a 13.5x13.3 "1.20 size" pattern prop...maybe that one?

NM2K

My Feedback: (14)

The 13.5 x 13 sounds like a winner to me.


Ed Cregger

Harry Lagman

I'd try several including the existing 13 x 11 (should do somewhere around 10K static), the suggested 13.5 x 13.3 and an APC 13 x 13 Narrowblade. Try a couple of 14s too like the APC 14 x 10 and 14 x 12.

Be sure to try a few props out - the "best prop" selection depends on four sets of data: your airframe's aerodynamic characteristics, your engine's power delivery characteristics, your flying style and your overall criteria of what is "best".

Chancho

Thanks All!

I really appreciate everyone's knowledge and feedback. I printed this page out at work and afterwards it was off to my LHS. Dave, at Joe's Hobby by the house, didn't have anything past a 13x11 in the 13 size. He looked up the 13x12, and 13.5x13.3 etc, but showed discontinued by APC. (I'm sure I can find one on line somewhere..) I took home a 14X12 and will try that along with the 13x11. Before blowing the cage out of my Saito 100 bearing case, it turned the 13x11 9300 RPM static. I tuned it down to 8900 RPM which gave it plenty of room to run out in flight. It was a delicate setting to be sure not to lean it out too much and cause an overload situation. Anyhow, maybe the extra %22 HP in the FA-125 will turn the 13x11 a few more RPM or maybe it's enough to swing the 14x12? Hopefully, weather prevailing, I can find out and post the results.

Best Regards,

Phil Green

Chancho

Well, I found the recommended props and tried them. My engine is probably still not broken in as I only have 2 gallons thru it. I tried the 14x12 - wouldn't spin up. Tried the 13x13 - Not.. Tried the 13x13N and it liked it. 9500 RPM static, same as 13x11. Problem was that when it went up in the air it never unloaded.. I put the 13x11 back on and it ran it solid all day, 11 flights, with small adjustments here and there. With the Saito 125 vs. the 100 I have truly unlimited vertical with the Revolver and the 13x11 prop. Where as with the 100, it couldn't do the "Unlimited" vertical. Speed... I almost want to say that the Saito 100 was faster with the 13x11 than the 125. It could be the extra 1000 max RPM. So I guess with the 125 you've got a bit more torque, but you sacrifice your max RPM. Not the massive %20 gain I was expecting, but after reading others reviews about the 125, I guess I'm on par.

Thanks again for everyone's help in all of this...

Phil

blw

My Feedback: (3)

At 2 gallons of fuel you engine is well broken in.