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Old Feb 13, 2013, 10:55 AM
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United States, OH, Middletown
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OS Max .10 & .15 Questions

Fellows, please help me out.

I'm old school. Always used OS loop scavenged engines from the '60's era. Once bought a new, later-issue OS .10 that had a flat top piston (Schnerlie?SP). It would sag when unclipping start battery, indicating need, for say, 15% nitro. Back then, I always used Fox fuels with 5% nitro. I still insist on some castor oil.

The newly advertised OS 10 LA says 5-15% nitro. Can anyone yea or nay this model OS engine? I don't want a screaming meanie engine. I fly on wing area, not power.

My old engines do not have a muffler in the OS .10 size. Old OS .10s on Ebay seem too dear in price..., so I'm thinking why not just buy the newest LA model.

This is for a new Prairie Bird 50. Wanted to put a PAW .061 on it but kit wood is not of typical Free Flight lightness. So.., model would never take off from grass when built from the kit wood. My next PAW model up in size are three PAW .19s.

Would someone who values easy-handling get along with a OS .10 LA engine? Or would it be peaky, over-compressed and not like bigger props?

NOS older model OS .10s with mufflers are higher cost than the new OS .10 LA. Should I spring for a new OS .10 LA for $62.98 + 3.99 shipping, or pay same or more for the engines I'm used to using? Most new engines back then never came with mufflers. They were seldom-purchased accessories.

If an expert here could offer a brief chronological history of OS Max .10s & .15s, even .19 model designations plus opinions of each, I would be so thankful. IE, can C/L venturis be removed, thus allowing model ? OS R/C carb in its' place. Handling qualities, etc.


I fly R/C & Free Flight. Thanks for any expertise offered,

ScratchbuildrSAM AMA # 28854 SAM # 1312
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Old Feb 13, 2013, 11:10 AM
supreme being of leisure
ZAGNUT's Avatar
Tel Aviv, Israel
Joined Jul 2004
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the little .10FSR was a lapped iron engine with schnerule porting and came with a stock muffler. interesting thing is that it had no pressure nipple on the muffler and no air bleed screw on the carb yet was a real sweatheart to run and always idled like a dream with perfect transition. back then i always used K&B 500 fuel which i believe was 7.5% nitro.

after that came the FP and the LA, no experience with them.
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Old Feb 13, 2013, 01:41 PM
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Sweden
Joined Jan 2008
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The FP models are better than the FSR ones. You get a modern ABN engine (in contrast to the iron/steel construction of the FSR) and a low-end adjustment on the carb. The LA version is then a step back towards an engine that is milder ported (no boost port) and should handle larger props better.

The OS Max are older cross flow engines (baffle stepped pistons) and they are fine too, if that's the type of engine you're after.
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Old Feb 13, 2013, 02:31 PM
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If I have an engine sag when the battery is disconnected, first thing I do in put in another glow plug.
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Old Feb 13, 2013, 03:10 PM
supreme being of leisure
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Tel Aviv, Israel
Joined Jul 2004
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Quote:
Originally Posted by surfer_kris View Post
The FP models are better than the FSR ones.
you have to be careful with statements like that, the only size engine where the FSR and FP are on anywhere near the same level construction wise is with the little .10

there was never a .15 or .20 sized FSR, the smallest aside from the .10 was the .25FSR and it was on a totally different level with ABC construction, ball bearing crank and two needle carb...well there was a .21FSR but i'm pretty sure it only came in marine and car versions...anyways, you could never compare a .25FSR or .40FSR to the same displacements from the FP line.
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Old Feb 13, 2013, 03:29 PM
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Israel, Ramat HaSharon
Joined Nov 2003
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At least write the guy's name right...

Either Schnuerle (English form), or Schnürle (source German).

Other 'spellings' of this name are wrong.

...And the 'e' at the end is audible, not silent.
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Old Feb 13, 2013, 04:18 PM
supreme being of leisure
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schnell!
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Old Feb 13, 2013, 07:15 PM
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United States, OH, Middletown
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Thanks Guys.

Continued research reveals I have a '64' OS .10. I just removed exhaust butterfly.
Anyone have a OS-741 muffler for above engine to sell?

Also, then a .10 FP LA IS a mild sport motor? Are users happy with them?

Thanks,

ScratchbuildrSAM
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Old Feb 13, 2013, 07:46 PM
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Quote:
Originally Posted by ZAGNUT View Post
the little .10FSR was a lapped iron engine with schnerule porting and came with a stock muffler. interesting thing is that it had no pressure nipple on the muffler and no air bleed screw on the carb yet was a real sweatheart to run and always idled like a dream with perfect transition. back then i always used K&B 500 fuel which i believe was 7.5% nitro.

after that came the FP and the LA, no experience with them.
K&B 100 was 5%, 500 was 12.5% and 1000 was 25%.
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Old Feb 14, 2013, 03:31 AM
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Sydney Australia
Joined Mar 2005
924 Posts
I have a control line version 10FP and fitted the non airbleed carb from the 10 FSR.
It runs perfectly.
It also has an extra section in the muffler & is incredibly quiet, quieter than many electrics.

I'm running my standard fuel mix with 5% nitro.
I'm delighted with it. - John.
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Old Feb 14, 2013, 08:47 AM
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United States, OH, Middletown
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Thanks Guys. The extra muffler section would definitely be of interest to me.
Hate noise. My diesels are quiet. Geared electrics are too loud! Imagine that.
After-mufflers are really neat on diesels for quiet operation.

I fondly remember K&B fuels as well as Fox fuels. Fox literature states Fox fuels are still available. I would readily buy Fox fuel. Has to be ordered by the case. Would be great to group order and pick up at Muncie. Any others near SW Ohio wanting Fox fuel??? Possibly Lee Cambell could take orders?

Anyone have 1st hand ownership experience of using the currently available Max .10 engine. Was outbid on a muffler on Ebay last night for my old '64' .10.

SctratcBuildrSAM
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Old Feb 14, 2013, 09:30 AM
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Canada, ON, Cottam
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The LA and FP .10 and .15 are great motors for a bushed motor, and easy to handle. I find them much faster than the TT. and about the same power as the somewhat older old school iron OS .15's. I tried boring out the muffler on the LA and it doesn't make a measureable difference in rpm. Sometimes I couldn't even hear mine running when the bigger motors are flying around me. The LA .10 seemed to like the head shim removed in mine. Goes good enough to fold up wings on two planes now. (pout, sob) The good thing about the LA's is that they are ABN(C) and there is less damage on a lean run as compared to the old steel ones. unless it is prolonged.
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Old Feb 14, 2013, 09:36 AM
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I've always enjoyed my FP & LA engines. They've always been reliable, ran with very little fiddling, and snapped back for more when I've driven them in the ground.
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Old Feb 14, 2013, 10:28 PM
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United States, OH, Middletown
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Thanks fellows.
Found a good value on a .10 and bought it. Has muffler with it too.
Now.., I also wouldn't hesitate to pick up the natural color .10 LA.
Thanks for the inputs!!!

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Old Feb 15, 2013, 09:09 AM
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I found you can get them real cheap at swap meets because everyone is going electric now and wants to get rid of them, and no one wants them for that reason too. A new one, or low time one for $20 is pretty common.
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