OS LA10 useful or not?

[Andrew Tinsley]

Hello All,
I have acquired an almost new (doesn't look as if it has been run)  OS LA 10. It came as part of a deal and obviously it is in R/C format. This engine is between sizes for me. I have plenty of 1/2 A experience and also the bigger stuff, but I am stumped as of what to do with this engine. Any suggestions as to venturi and spraybar sizes? Not to mention prop sizes for running in and flying?
  It looks as if something like Jim Thomerson's Cheap Thrill would be big enough to take this engine. Obviously the LA 10 isn't a screamer like a TD or Norvel and I would assume it makes similar power with a larger prop turning more slowly?
  Anyone have any experience of this one? It has the stock OS silencer which dwarf's the engine!

Regards,

Andrew.

[Bootlegger]

 Andrew, I am running an OS Pett .099 on a Jr Ringmaster that weighs 16 Oz and I like the way it flies and the way the engine runs.
 With the .099 I have to run mostly castor fuel so I don't "cook" the engine, how ever I would say a blend of castor/syn will work on the .10.
 Prop wise I am running  7" dia with pitches from 4-5", with 50' lines of .012 dia.
 As for the venturi dia I would start with what ever the r/c throttle is and adjust from there...

             Hope that this helps...

[Steve Fitton]

I have the FP-10 on my sons Flitestreak Trainer.  Stock RC carb jammed wide open, APC 7x5 prop, stock muffler, Sig 10% Champion fuel.  It runs great and is super quiet.  The FP is strong and I bet it would easily fly something like a Jr Flite Streak.  Your LA should be pretty much the same.

[James_Mynes]

I just got a venturi off eBay for the FP 10. Packaging specified FP 10 on this one. I also have bought some for the FP 15, which also fit the FP 10. All of them have an ID of .237.
Jim Lee, a vendor on here, sells venturis that will fit. He offers various ID choices. Perhaps get one from him in the .230 range, and drill it if you need more.
Needle valves for the FP 15 also fit the FP 10. I have no idea if they will work for the LA 10, as I don't have one.
Good luck with it!

[Andrew Tinsley]

Thanks everyone,

[Andrew Tinsley]

I don't know which key I hit to get the above! Again thanks for the info. Jim I took a look on Towers and they still have the NVA and venturis for the FP 15. I looked at FP 10 next and surprise, surprise the NVA and venturis were not listed! Are you sure the FP10 and 15 have the same venturi and NVA? If the answer is yes, I can get them from Towers and see how this little fellow runs!

Andrew.

[Gary Mondry]

Andrew,

You might be interested in this previous discussion: http://stunthanger.com/smf/index.php?topic=27498.0

Gary

[Akihiro Danjo]

Andrew san,
FP 10/15 venturi will not fit LA10 because the bore of LA10 is slightly larger than FP.
FP venturi will be loose.
Aki

[Andrew Tinsley]

Thank you Aki and Gary,
That has saved me the expense of finding that the FP15 venturis and NVAs are not suitable for the LA 10. It seems that my best bet will be to make my own venturi and use a small NVA assembly from the PAW diesel engines of similar size.
  One useful piece of information would be the free unobstructed area of an FP 10 venturi. I suppose that is asking a little much, but if you don't ask.......... Also what size plane is suitable, I am not familiar with the Jnr F/Streak or Junior Ringmaster. Anybody got approximate wing areas and weights for these two? I am sure there are some English designs from the '50s and '60s that would work well.

Thanks again,

Andrew.

[DanielGelinas]

I have my os la10 running on a sig akromaster. Got the venturie from Jim Lee (in the vendors corner).
Engine runs great on 10-23 brodak fuel.

-Dan

[Steve Thomas]

I am not familiar with the Jnr F/Streak or Junior Ringmaster. Anybody got approximate wing areas and weights for these two? I am sure there are some English designs from the '50s and '60s that would work well.

Hi Andrew, the Jr Flitestreak is 230 sq.in.  Mine flew well at about 16 oz with an Enya 09-IV, so you'd expect similar results with an LA 10. 

As far as older English designs go, the 'Mirabilis' looks really good (though I think it's from the 70s).  The Mercury Marlin is also very pretty, although it probably wouldn't be as capable and looks a bit fragile. Another one would be Gordon Cornell's Princess - I think you'd need to keep it very light.

Steve

[rustler]

How about a suitably enlarged T-Tray? 

(I've just had the plan enlarged x1.5 for an MP Jet 1cc).

[Akihiro Danjo]

Hi Andrew san,
I am sorry that this is not the data of LA10 but FP10.
I have found that the stock OS venturi is too large for stunt run.
I use 6.0mm OS stock venturi with 4.0mm MVVS short needle assy.
This combo is still powerful and eats lots of fuel for its size, so I think 5.9mm may be also good.
This means that if you use with 3.5mm needle, you will need about 5.5mm venturi.

This profile Mustang is built from a Japanese kit.
38" span, 295 sqinch wing area and weighs 450grms=16oz.
.012" -44.6ft (e-e) wire. FP10 with Kyosho 7x4 prop, 12400rpm.
Fuel is 15 or 20% nitro, 22% all syn lube.

Aki , excuse my bad English

[Geoff Goodworth]

Aki, your English is orders of magnitude better than my Japanese.

I know that we are talking about FPs when Andrew asked about the LA but for some odd reason, the holes in the FP 10 crankcase are 4mm and the diameter of the standard front mounted NVA is reduced across the venturi opening so a 3.5mm NVA will be loose in the crankcase and venturi. I would expect a 3.5 mm NVA to leak.

[Akihiro Danjo]

Yes, that would be the reason why I chose 4mm NVA for my FP.
I think the hole in LA10 case maybe about 3.0mm though it is only one.

Aki

[john e. holliday]

Andrew, take a look at the British Peacemaker.  It should work well for that little engine.  Need to get some kerosene now that I have found my stash of diesel ingredients so I can get mine in the air.

[Andrew Tinsley]

Thanks everyone!
Lots of good information there! I have had a message from Geoff Goodworth about a 90% Peacemaker. I usually run my Peacemakers with Oliver Tiger power. So I would find a full sized Peacemaker a bit underpowered with an LA 10. Geoff says that a 90% Peacemaker is 230 sq inches and that sounds like a Jnr Flitestreak!
  Thanks for the venturi area data Aki, much appreciated! As for a Princess, well the last time I built one (over 50 years ago) finished up with an AM25 rather than the planned AM 10! It is VERY easy to put weight on a Princess build. Mirabilis sounds a great idea, I built one a year or so ago and found it a great little machine, why didn't I think of that before? I am tempted with another build of Jim Thomerson's Cheap Thrill, a largish half A machine and very nice looking.
  Thanks again everyone, it has been a really useful thread and as usual, I need to clear the workshop and get building (once I can make my mind up what to build!)

Andrew.

[Dennis Leonhardi]

Andrew, I have a couple of OS and Thunder Tiger .10 engines and think there are some great suggestions here, especially the Ringmaster Jr. (or Stuntin' Ringmaster .19 Jr., as Estes called it) and the Jr. Flite Streak with 230 square inches of wing area.

But in this and the earlier post, there may be some misinformation; perhaps specific OS part numbers and images will help.

.10 FP-S:

Venturi - #21112003 http://www.osengines.com/parts/images/21112003.jpg
Needle Assembly - #21111006 http://www.osengines.com/parts/images/21111006.jpg

.15 FP-S:

Venturi - #21712010 http://www.osengines.com/parts/images/21712010.jpg
Needle Assembly - #21711100 http://www.osengines.com/parts/images/21711000.jpg

As you can see, these are quite different.

The .15 LA-S uses the same venturi as the FP.

I'll add my 2 cents in recommending Jim Lee - he's provided me with some excellent items quickly at very reasonable prices!

Incidentally, I have hundreds of pages of parts lists for OS engines going back to the '60s or earlier.  Should anyone here need a part number, shoot me an email and I'll try to help.


Dennis
 

[Bootlegger]

  Aki, I sent you a private message on the Mustang.  Thanks Gil Causey AKA Boortlegger

[dennis lipsett]

Andrew,
All of the info regarding both the fsr/fp/la engines is correct. Any of the older designs that you used 15's in will fly as well or sometimes better that before.
I'm putting up 2 pictures of a Sterling and a Pat King Jr Ringmaster both with OS10FP engines. They get flown on 55 foot of .012 line with 7/5 props and are still not too slow. They are capable of doing most of the maneuvers quite well. You owe it to yourself to get one airborne. I understand your medical problems and can assure you that these are really gentle on everything including your wallet . A 2 ounce tank will fly a long time.

Dennis

[Garf]

I now have 2 OS 10 FSR that need P&C. They don't seem to hold up well.

[dennis lipsett]

My OS10FSR engines (2) are over 30 years old and have been used in R/C and C/L models and still function perfectly. Environment and care of these engines are important to maintain a long service life. They were just retired from a Sterling P-38 that was passed on to another modeler. Models go, but my engines always remain with me.

Dennis

[john e. holliday]

Hey, Phil(Garf), you might try the trick George Aldrich told us about back in the days of racing.   Take the piston and put it in the kitchen range oven at the highest temp for a few hours.   It may grow a little and it may not.   It worked for us until we could get someone to replate every thing.