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Engine basics => Engine set up tips => Topic started by: Christopher Root on January 19, 2020, 08:41:20 AM

Title: OS LA-46 straight Venturi
Post by: Christopher Root on January 19, 2020, 08:41:20 AM
I’ve got a LA-46 R/C that I would like to convert to C/L.  Where can I get a straight Venturi and NVA?  How about a metal back plate?
Title: Re: OS LA-46 straight Venturi
Post by: Peter in Fairfax, VA on January 19, 2020, 01:58:32 PM
The LA 46 is a nice engine.  Had a good season with mine.  Comments follow, some a repeat.

Venturi:  The O.S. is just fine, but the aftermarket ones are also good, and offer more choices as to diameter.

NVA: The PA is good, as is the Super Tigre.  However, the O.S. and the Enya, while adequate, do not match my style.  Further note:  If installed on a profile plane, bend over the needle or cut it and install a squared wheel collar so it is really, really short.  That way, it will survive inverted landings. 

Further notes:  There is a pinned article on this board regarding setup, if that helps.
Title: Re: OS LA-46 straight Venturi
Post by: Geoff Goodworth on January 20, 2020, 04:26:04 PM
For most applications, the standard OS venturi (7.1mm ID) is too big.

The FP 20/25 venturi fits and is 6.55mm ID. That is probably too small. My LA 46s are very happy with the FP 20/25 venturi reamed out to 6.75mm ID — the same as the small venturi that used to come with early FP 35s and FP 40s.

All these numbers are for engines using the factory OS 3.5mm OD spraybar.