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Author Topic: OS 40SF for CL stunt?  (Read 1339 times)

Offline Mike Scholtes

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OS 40SF for CL stunt?
« 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?

Offline Clint Ormosen

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Re: OS 40SF for CL stunt?
« Reply #1 on: March 22, 2007, 02:45:05 PM »
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.
-Clint-

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Offline Leester

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Re: OS 40SF for CL stunt?
« Reply #2 on: March 22, 2007, 03:25:59 PM »
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).
Leester
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Offline RandySmith

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Re: OS 40SF for CL stunt?
« Reply #3 on: March 22, 2007, 05:47:23 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

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

Offline Mike Scholtes

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Re: OS 40SF for CL stunt?
« Reply #4 on: March 22, 2007, 07:19:09 PM »
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.

Offline Clint Ormosen

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Re: OS 40SF for CL stunt?
« Reply #5 on: March 22, 2007, 08:22:10 PM »
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!
-Clint-

AMA 559593
Finding new and innovated ways to screw up the pattern since 1993


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