stunthanger.com
Engine basics => Engine set up tips => Topic started by: Mike Scholtes on March 21, 2007, 06:18:04 PM
-
I have an OS 40SF in RC configuration with little run time on it, looks new. I am the original owner. This is the ball-bearing, rather hefty engine that as I understand it is the side-exhuast sibling of the 40VF. Mine is the ringed version. A flying buddy has one, the ABC version, converted to CL use in a Pathfinder that it pulls very well. Question: Is the 40SF a good stunt engine if fitted with venturi and CL NVA, based on anyone's experience out there? I would expect a high-RPM, flat prop, straight 2-cycle run like the modern crop of high-revving engines. Further, would the ABC piston-liner be preferred to the ringed piston-liner?
-
Hi Mike,
I've onle seen one OS 40SF used for stunt and I believe it had been modified. They do weigh more than the FP or LA. What model are thinking of putting it in? I'd think if you run it like you describe, It will have a ton of power, but I don't think you'll find it a user friendly engine.
-
Don't know how user friendly it is, but OS used to make a 40-46 SF S. Tower still carries the venturi (LXCXOO 11.49) and NVA (LXCR55 21.49 ouch) they list the 20-25 NVA for it also (LXCR49 11.49).
-
I have an OS 40SF in RC configuration with little run time on it, looks new. I am the original owner. This is the ball-bearing, rather hefty engine that as I understand it is the side-exhuast sibling of the 40VF. Mine is the ringed version. A flying buddy has one, the ABC version, converted to CL use in a Pathfinder that it pulls very well. Question: Is the 40SF a good stunt engine if fitted with venturi and CL NVA, based on anyone's experience out there? I would expect a high-RPM, flat prop, straight 2-cycle run like the modern crop of high-revving engines. Further, would the ABC piston-liner be preferred to the ringed piston-liner?
Hi Mike
The OS 40 and 46 SF both were made in a stunt version, they had a special stunt crankshaft,Although I have seen some nice engine runs from the 46 they were just OK stunt engines in the reworked RC versions with the 46 being a much better motor that the 40, that said you could use the 40 in a high RPM flat run using a 4 to 4.5 pitch prop. If you want to convert them look for cranks that have the letters SF-S on the back.
And neither the 40 or 46 SF are as good as the 40VF or 46VF, I reworked many of all these motors and the VF series always seemed better for our applications.
They use a 60 size NVA I do not think the OS LA one will fit
Regards
Randy
-
Thanks everybody! Looks like I am best advised to just put this in an RC model and stick with a proven CL engine. My plan was to put it in my Imitation after building a "true" profile fuselage for it. The semi-profile fuse built per original plans has developed cracks around the fuse-wing joint and behind the wing TE. Not confident I can repair it safely, so a new fuse is in the works. At 631 inches it would need a really strong 40...to fly in P-40 class! Or, leave the LA 46 on it and just fly PA like always.
-
Thanks everybody! Looks like I am best advised to just put this in an RC model and stick with a proven CL engine.
Good choice!