stunthanger.com

Engine basics => Engine set up tips => Topic started by: frank mccune on April 18, 2014, 07:51:56 AM

Title: Which is the better Stunt engine? O.S. .40S or O.S..40 LA
Post by: frank mccune on April 18, 2014, 07:51:56 AM

     Hello All:

     I "found" two O.S engines that I may use to power my "new" Fancherized Twister.  In my bag of engines, I found an N.O.S. O.S. .40 S.  This is the 1970's O.S. That has the single rear ball bearing and a baffle on the piston.   The other engine is a new O.S. LA .40.  Since the plane has been drilled and tanked for either engine, which engine would be the better choice?

    When I built thjis plane about 30 years ago, I had planned upon an O.S. .35 Stunt for motivatiion.  Would the .35 be a better choice than a .40 due to its lighter weight?  Would it have ample power?

                                                                                                                                     Tia,

                                                                                                                                     Frank

Title: Re: Which is the better Stunt engine? O.S. .40S or O.S..40 LA
Post by: Tim Wescott on April 18, 2014, 10:51:35 AM

I would go with the 40LA, although I think there will be people recommending any of the three.

Or I'd trade the 40LA and the 40S for one 46LA, and use that...

Title: Re: Which is the better Stunt engine? O.S. .40S or O.S..40 LA
Post by: Andrew Tinsley on April 19, 2014, 12:00:17 PM

I have never had much joy with the LA40 compared to the LA46. The LA46 is almost idiot proof while the LA40 isn't. I have seen one excellent running LA40, but it isn't too common.

Andrew.

Title: Re: Which is the better Stunt engine? O.S. .40S or O.S..40 LA
Post by: EddyR on April 20, 2014, 05:42:46 AM

The 40S is a much better STUNT motor but it is not as powerful as the LA40. n1

Title: Re: Which is the better Stunt engine? O.S. .40S or O.S..40 LA
Post by: James C. Martin on April 27, 2014, 07:15:02 PM

have an Dee Rice oriental with an os la 40 on it used a venturi mounted needle instead of the remote one, and this airplane is very smooth and consistant running has plenty of power .

Title: Re: Which is the better Stunt engine? O.S. .40S or O.S..40 LA
Post by: richardhfcl on April 28, 2014, 11:01:00 AM

What is this "40 S" of which we speak?  Is it the same as a "40 H?"  I'm familiar with the S
designation used in conjunction with the 30 and 35, but not the 40.  Thanks!

Title: Re: Which is the better Stunt engine? O.S. .40S or O.S..40 LA
Post by: frank mccune on May 08, 2014, 05:23:26 PM

     Hello Richard:

     The O.S. .40 S is a stunt from the 70's.  It has the regular venturi and spraybar and was not a converted RC engine.  It also has a single ball bearing in the rear and a bronze bearing in the front.  I think that the timing was a bit less wild than the .40H which was a RC engine.  It also has a single ring with a baffled piston.  It seems to run very well!  I have it in a Green Box Nobler as we speak. I have not flew it yet but I will soon.

                                                                                                               Thanks for all of the replies,

                                                                                                               Frank

Title: Re: Which is the better Stunt engine? O.S. .40S or O.S..40 LA
Post by: Dave_Trible on May 08, 2014, 09:37:37 PM

It may just be personal preference but I'd prefer the non-schnurle .40S.  This is a slower turning but higher torque type motor that can turn a wider blade prop with more pitch.  I think this will yield more usable thrust than the LA .40 which I admit I never had much love for. Given a choice,  I'd take a red head McCoy over an LA .40.

Dave

Title: Re: Which is the better Stunt engine? O.S. .40S or O.S..40 LA
Post by: M Spencer on May 15, 2014, 07:38:46 AM

(http://www.osengines.com/history/osm640/osm-1970-max-h40s.jpg)