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Engine basics => Engine set up tips => Topic started by: frank mccune on April 14, 2014, 06:23:50 AM

Title: What is the correct way to run the O.S. .40 and .46 engines for stunt?
Post by: frank mccune on April 14, 2014, 06:23:50 AM

    Hi:

    I have been watching several friends of mine run their O.S LA and FP engines as stunt engines.  They adjust these engines to run in a very rich 4 cycle and use large props.

    It is my understanding that these engines are best run in a "wet" 2 cycle with low pitched props due to their P&C materials.

   These engines appear to be very good engines for use as they start easily, easy to adjust and hold setting very well.

     Any suggestions or comments?

                                                                                                                              Tia.

                                                                                                                              Frank


   

Title: Re: What is the correct way to run the O.S. .40 and .46 engines for stunt?
Post by: Tim Wescott on April 14, 2014, 08:46:58 AM

I'm having a lot of success running my LA46 and LA40 in a wet two-stroke with 12.25 x 3.75 APC props, or ThunderTiger 11-4.5 props.  That's how most of the successful fliers in the Pacific Northwest tend to run their engines.  I seem to get the best flights when the engine runs in sort of a ragged 2-stroke, like it's thinking of going to a 4-stroke, in the first few laps of the pattern.

There's a "list your LA46 set-up" in this forum.  You can pick through there and see what you think.

Title: Re: What is the correct way to run the O.S. .40 and .46 engines for stunt?
Post by: Steve Helmick on April 15, 2014, 03:50:35 PM

There's a lot more to it than just prop and fuel and NV setting. Muffler restriction is a major deal, along with venturi size and tank, muffler pressure or not, glowplug, etc. "The Setup" (i.e., the one that works) includes everything related to the power system. IMO, you need to investigate your friends "setup" in much more detail, and take notes.  I have noticed that folks will take the notes on a complete, known to be good setup and not get all the details right, and wonder why it doesn't work at all.  Details count! H^^ Steve

Title: Re: What is the correct way to run the O.S. .40 and .46 engines for stunt?
Post by: Tim Wescott on April 15, 2014, 04:02:08 PM

Quote from: Steve Helmick on April 15, 2014, 03:50:35 PM

Details count! H^^ Steve

Which is why you should go through that WHOLE THREAD!

And if it doesn't work at first (mine didn't), keep going over the thread and trying things until you find a combination that works.

http://stunthanger.com/smf/index.php?topic=21156.0 (http://stunthanger.com/smf/index.php?topic=21156.0)

Title: Re: What is the correct way to run the O.S. .40 and .46 engines for stunt?
Post by: Mark Scarborough on April 15, 2014, 04:51:03 PM

Quote from: Tim Wescott on April 15, 2014, 04:02:08 PM

Which is why you should go through that WHOLE THREAD!

And if it doesn't work at first (mine didn't), keep going over the thread and trying things until you find a combination that works.

http://stunthanger.com/smf/index.php?topic=21156.0 (http://stunthanger.com/smf/index.php?topic=21156.0)

Like which prop,, what fuel,, and of course,, use a tach,,