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Engine basics => Engine set up tips => Topic started by: Steven Kientz on April 11, 2009, 04:16:37 PM

Title: os 35fp
Post by: Steven Kientz on April 11, 2009, 04:16:37 PM

Just picked up a hardly used 35Fp from a hobby shop I frequent when I visit my parents. I need to convert it to C/L. i see where Tower has parts listed but am a little confused about the 2 venturis they show. One is listed for the 40FP( large)and one is listed for the 20-25FP(small). Tower shows the OS part # as being the same, yet they have different prices?
This engine will probably end up in a Brodak Hurricane profile that I have yet to start on.I figured I should get the parts before they disappear.
If anyone has suggestions as to aftermarket parts(venturi, NVA & muffler) please chime in.

Thanks
Steve 

Title: Re: os 35fp
Post by: Clint Ormosen on April 12, 2009, 01:48:15 AM

This doesn't really answer your venturi question, but my advice is to send it to Randy and let him work his magic on it. You'll get it back re-timed with the right size venturi and a PA style NVA.

Title: Re: os 35fp
Post by: Paul Smith on April 12, 2009, 06:34:24 AM

I've bought several used FP35's and 40's.  I just use the Tower parts.  They work fine.  So does a ST NVA and a home made venturi hacked out of Nylon.  I'd say buy the small bore venturi and drill it if you think you need more power (which you won't).

You can save the price of a tongue muffler by sawing off the back end of the stock muffler and bolting & epoxying on an aluminum plate.  You save about an ounce and $20.

Title: Re: os 35fp
Post by: Steven Kientz on April 12, 2009, 07:16:44 AM

I'm just a sport flyer so it would be hard to justify(to my better half)why I had to send a motor to be reworked. Randy is at the top of the list if I ever decide to start competing.I figured the Tower parts would work, thanks for the muffler tip Paul, had never thought of that.

Thanks
Steve

Title: Re: os 35fp
Post by: Mark Scarborough on April 12, 2009, 01:24:27 PM

From my experience, the FP 35 exhibis none of the dreaded "issues" that the FP 40 does, that being run away,, ( overspeeding during the flight) I would say that depending upon what airframe you are bolting it to, the FP 25 ventruri  would be a good choice,, I think they are about .275 ID? This with a ST styled needle valve assembly will get you in the ball park. One thing I would reccomend is to not choke down the exhaust outlet, in my experience this tends to build heat in the motor and makes for a somewhat erratic run. use fuel with at elast 22, preferable 25% oil, and at least half castor. then enjoy,, its agreat motor

Title: Re: os 35fp
Post by: john e. holliday on April 14, 2009, 10:31:46 AM

Get ahold of Jim Lee at Lee's Machine Supply or Shop.  He has all sizes of venturis and can help a lot if you are just starting out.  He is in Vendors corner.  DOC Holliday 

Title: Re: os 35fp
Post by: Steven Kientz on April 14, 2009, 03:10:13 PM

Thanks for all the great advice. Now if someone could keep me from building when I should be flying, I might just learn the pattern.

Steve