OS LA .46 set up

From all I gather, the LA .46 from O.S. is a great stunt engine right out of the box. Is there any need to modify the needle valve set-up? Is anyone running the engine with the remote needle set-up? If so are there any problems with this set-up? What about the factory venturi? Finally, how about the blue finish? When these engines first appeared I thought the dark color might lend itself to cooling problems, especially in cowled installations. What is this engine's equivalent in terms of power? ST .46? How many square inches of wing would you bolt it on? Man, I'm getting one of these engines next week. Now all I need is the gouge on setting it up.

Regards,

Sterling Hart

Try the search function. Type in "OS .46 LA", check "and" in the next line, and be sure to check for the past year and archives if you have time.

I've grown to like the blue. For some reason, it doesn't seem to get the brown grunge buildup. Cooling is not a problem, anyway.

I highly recommend doing "the setup" before you ever run the engine. The venturi should be .281" -> .295" or so with a .156" spraybar like a ST clone or Nelson/PA NVA (better unit, more $). If it is smaller than that, you can drill it out.

There are a lot of muffler choices, thankfully, as the stock unit is "like a rock". This is a great engine for most .40 designs, such as the Buccaneer 740, Brodak Cardinal and Pathfinder, Legacy 40, etc. It would also be great in a lot of Classics like the Nakke, Lark, Skylark, Simonds P-39 and Shoestring, etc. Steve

Great motor right out of the box. I would follow Steve's suggestion's. RSM has venturi's and needle valves in stock and I think motors to. www.rsmdistribution.com

My experience has been the remote NVA is quite satisfactory. I asked on this forum (5th. June "LA40/46 NVA") if anyone could categorically say why a venturi mounted NVA should be better, no one could/did. Having said that, I have personally spoken with one person here in England, who says "Remote - terrible problems, venturi mounted - no problems". I am convinced his problems were not because of the remote NV position, but some other cause. Other people also swear by the Venturi mounted NVA.
Notwithstanding my theories, the customer is always right!!! I can sell you a spike NVA and venturi assy. for the 40/46 LA for £12, and an old type Merco silencer (1.75oz) for £11.50!!
Regards, Ian R. [email protected]

Hey Sterling!

You'll like the LA -46 alot. Jimmy is running an LA-40 with the remote needle on a profile job, and it seens to work fine that way. My latest Time machine 50 is set up with the LA-46, but I put in a ST needle assembly so I am back to the front needle location with a .285 venturi. They are nice motors for the cost.

What you gonna put it in, I've seen LA 46s powering everything from Brodak warbird profiles to Sig Magnums.....

PS we finished your old Ruffy, it should be flying very soon, it looks good!

I'm running a box stock LA 46 with the remote needle, APC 11 1/2 x 4.
Runs great. Only problem I've had is the engine does not cut clean when running out of fuel. Have changed tanks and tried other things,
but read on this forum that the remote needle was the cause. Does not bother me enough (yet) to make a change.

Recently helped Brad Parker do first runs and flights with his LA .25 Primary Force, with stock NVA, muffler, etc. A few weeks before that, helped Ben Jones with his LA .25 Ringmaster. I wasn't impressed with the rear NV, as the fuel runs back out of the hose. That doesn't happen with the front NV, as the hose is under the fuel head. It made hand starting more trouble, IMHO. I would still suggest the first gallon of fuel be all castor oil, 25%-29%. After that, use 22% half n' half. Steve

I thought that I would add my set up to this post in case anybody does a search for a 46 la set up.

OK, here goes. I bought a R/C version and installed a .272 venturi and a .135 spraybar both from Russ Gifford. You will not be disappointed with his stuff. I then replaced the plastic backplate with a Tower 40 metal one. I broke it in on the run up stand and ran about 3/4 gallon of SIG 5% Champion fuel through it. I did the 2 minute run and cool off routine for the first 24 ounces, then increased the run time to 4 minutes for the next 24 ounces. Then bacisally ran the engine for 7 mins runs after that.

I'm using an APC 12.25 x 3.75 prop cut down to 11.75 dia. I just rounded off the tips, and balanced the prop. I'm using a Thunderbolt R/C long glowplug with an idle bar. The fuel is Powermaster 10/22 with 5CC of Grape fuel fragrance added to it.
I'm using a Sullivan 6 oz RST Flex tank set up for uniflow and muffler pressure. I run the uniflow vent to the middle of the tank (fore and aft) positioned it about 1/2 inch below the TOP of the tank near the outboard wall. I adjust this up or down to get the type of engine run I want during upright and inverted flight. I like to have the engine speed up just a touch during inverted. It helps a bit with the vertical stunts. BTW, my engine bearers are under cut 1/4 inch and the engine sits on top of 1/8 phenolic pads. I'm using an RO-Jett muffler with the stinger drilled out some. I drilled out the stinger for another perceived problem that really wasn't a real problem. My guess a stock muffler would work just fine. I have a Dubro exhaust deflector on the outlet and it is cut down, at an angle, to 1 inch after the bend. I launch at about 10,200. This speed will vary depending on weather conditions. I like to "lean" it out a bit more when the weather is hot and/or windy, like we had at Rockford. I also use a Sullivan "Crap Trap" filter and Prather "pink" medium fuel line. I feel that the Prather fuel line is a lot stronger and it holds up to the nitro better. I use a SIG 2" spinner and yes, I have to enlarge the cutouts some for the APC prop.

I fly, er make that flew, the 47 oz Actroma on 62 foot (eyelet to eyelet) 7strand lines using Ted Fancher's Precision Pro handle. Lap times were about 5 to 5.1 seconds. It's been a while since I timed my lap speeds.

I need to make sure that you realize that there were NO mods done to the engine other that adding the venturi, spraybar and a metal backplate. NO shims, NO grinding, NO nothing. Just run it and enjoy it. The engine cost me $65 and the backplate $3 from Tower. The venturi was about $12 and the sparybar was $15. I really can't remember what Russ gets for these, but the costs listed are close.

That should do it. If I have forgotten anything let me know.

The problem we have seen with the remote needle is the time lag between turning the needle and when the engine senses the new fuel/air mix. Most people are too impatient to wait for the change and keep turning the NV. Then, the engine REALLY changes and they have to scramble. We have also seen more air leaks with the remote setup. There are more connections, etc. so there are more places for the fuel to get bubbles.

The regular needle valve gives you much more positve results.

The remote needle sure does save your fingers and knuckles.

One question. Is this engine usually run in a constant 2 stroke setting or is able to run in a 4-2-4 configuration?

Randy,
Mine will do a nice 4-2-4 depending how "lean" you run it. I can set the NV to give me a nice 4-stroke in level flight and a nice break to 2-stroke on top. Or I can lean it out a little more and run a fast 4-stroke with a bit harder 2-stroke on top. I even ran a 2-2-2 run, but it does run hard in that mode. Lots of power though.

Crist,

I've got an OS35FP that has been worked on by our own Len Neumann here. The engine is in a classic plane and I've had pretty constant problems with it (no reflection on Len, could be a breakin or something else). I've been thinking about trying another engine and the OS46LA will bolt right in. I thought I might try it.

Hi Randy,
The OS LA .40 & .46 will swap with the OS FP .35 & .40. I have done it.
The LAs are user friendly, low in cost & will (.46) 4-2 break or no break. I've found if you go up in pitch you get more break, down in pitch less break or no break. BY&O 11-6 will give almost a classic break.
Zinger 11-5 will give little or no break.
I all so found to little oil can make the LA .46 run poorly (Hard to needle, not consistent). I like to run 25% mixture of castor & synthetic.

I second everything Crist has said, I have an LA 46 in a Buccaneer with almost an identical setup. That thing will run in any mode you want it to just depends on how you set the needle.

I made a .295 venturi and used a ST needle but found it to be a tad large. I stuck on a Bru-Line air filter and now it's just about perfect.

>I second everything Crist has said, I have an LA 46 in a
>Buccaneer with almost an identical setup. That thing will
>run in any mode you want it to just depends on how you set
>the needle.
>
>I made a .295 venturi and used a ST needle but found it to
>be a tad large. I stuck on a Bru-Line air filter and now
>it's just about perfect.

Ditto to the above. Have one on my High Noon, Randy, Stock out of the box. Supertigre venturi and needle, Bru-line filter. Tongue muffler. I run an apc 11-5 and set it rich. No chance of a run-away. 9500 at launch. Does the pattern on 3.25-3.5 ounces of fuel. You can't go wrong purchasing this motor.

I do find the L.A.46 an amazingly good engine even with stock unaltered timing as long as you treat it like an O.S. not a fox and use a lower pitch prop. For my red Humongous on 60 ft lines it just loves the A.P.C. 11.5 x4 and gives a strong two four run on very little fuel. I did change to front venturi and S.T. needle valve ass. and tongue muffler just because it seems more familiar to me' Also added a shim or two. dont remember how much. Randy youve seen it many times. At our contest on the end of July ,Chris Took 1st. in old time with it and I took third . Every time I hear it run I am thrilled . It makes me think of a Harley. Keith Varley

Keith!!

Glad you're herre.

I've finally got the OS35 running pretty well. I think. Pat Johnston and I noodled about it at some lenght and it seems OK now. But I would like to put in a motor that gives a more classic stunt run. It is, after all, a classic plane.

But I will probably stick with the OS35 as long as it doesn't go whack again.

BTW, I am starting to build my "new" classic plane. This will have a Magnum 53 (set up to run like an ST60) and should be a growler.

Just a note:

Well, I don't need to worry about putting an OS46LA in the Shoestring anymore. The Shoe met it's fate last weekend, the OS 35's last monsterous act. Quit in the clover in heavy winds. Man, what an ill fated engine...and plane as it turns out.

I used the OS .46 LA on my last Cardinal and the only trouble was an over lean run due to too low nitro in the fuel. It was 93 and the humidity had to be at least 95% Sunday. It went lean and the engine sagged, but the line pull was great, so I went into the four leaf clover (the killer maneuver) and it died. There I was at 10,000, no fuel, inverted and here came 4 Zeros out of the sun. Yep,ripped the engine right off the fueslage. Spare wing anyone? As to the remote needle valve, it's what I used with not a problem. The slight time lag forces you to make your adjustments a little more carefully. BUT ya gotta use a tach, not olde ears. Heh, heh. Note my new saying.

Here's a few pictures of Bill Trumbles Foamy Mustang which sports a La-46S in the nose. She's all stock in config. and flys his Mustang very well. This past week he changed out the Zinger 11 x 5 and went to the APC 12 x 4 with launch rpm's at the 10k area. Better performance yet again. Good line tension overhead. He's sticking with it. I did the Rit dye job on the APC's this week prior to flights,..just a cosmetic thing but they look nicer to me in black (Thanks Lou Scavone)

Tony

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Read more about Bills Stang here:

http://www.clstunt.com/htdocs/dcforum/DCForumID1/5503.html

>Here's a few pictures of Bill Trumbles Foamy Mustang which
>sports a La-46S in the nose. She's all stock in config. and
>flys his Mustang very well.

Where does the muffler vent end inside the tank ?

Don't quote me on this but I think as shown it is just going into the vapor space at the top of the tank. Sans muffler pres. set up the tube at the tank would be the overflow vent used for fuel fill service (been sprayed by this one before). This tank has been retired btw, in favor of a chicken hopper tank. This tank had erratic feed dynamic's at the end of run. We think due to it's rather deep design, this caused on/off/on/off runs at the end of the run. The chicken hopper gives nice clean shutdowns at the end of the run. He gets about 6 min's and change out of 4.5 oz's of 10% nitro fuel with the chicken hopper and 12 x 4 at 10k (ground set). I'll double check the plumbing with Bill and report back, maybe get a pic of the new tank setup also.

edit: I can confirm that the plumbing on Bill's tank, as pictured, is as I have stated. (the muffler dumps to the tanks vapor space at the top of the tank.) Also of note re: the La-46,..he dropped the size of the venturi down to a .250 but still maintains the factory remote needle set up. He wanted a little more suction at the venturi to help cure the remote needles lag and loss of prime during the engine start process. He gets one flips starts with this arrangement most of the time now. No picture of the chicken hopper tank set up as yet. But should have one by the weekend. Stand-by.