I'd like to replace the OS 46 LA on my tower trainer 40 and would love to put a 4 stroke on it. I do have a brand new Saito FA-56 looking for a home. But I just cant see how I could mount the 56 without some serious modifications mostly because of the way the carb sticks out the back of the engine a good inch or more. Also the throttle lever is on the opposite side of the engine unless. I could easy enough re-route the throttle linkage to the other side but the carb sticking out the back seems to be a real show stopper. Are all small 4 strokes made this way? I really like Saito engines at the moment and I know the 56 would overpower the trainer but it would be nice to fly the trainer again with a little more power and a reliable engine. I know I could go with a 2 stoke like the OS 55 AX but from what I've read, they seem just as problematic (as the LA) so I'm not impressed with OS at the moment.

Looking for suggestions for a reliable replacement for the 46 LA.

TIA
Shaggy

Shags, you could turn the carb around on the .56, which trainer is it, maybe show us a picture. Thanks, Dave

Hobbs is correct. It's real easy to remove the 2 carb screws and flip the carb 180 degrees. You may just need a slightly longer engine mount for it.

Just curious, what's problematic about your 46LA? Many people consider the LA to be a great trainer engine due to good reliability and ease of use.

The Saito .56 will be lucky to make as much power as your OS .46LA two-stroke. Four-strokes are not as powerful as two-strokes of the same displacement. The .56 Saito might have enough of a displacement advantage to come close to matching the .46 two-stroke, but certainly not more powerful.

Lots of folks mistake the better slow speed performance obtained when swinging larger diameter/lower pitched props for more horsepower. Put the same prop on the OS .46 LA and be prepared for a surprise. Yes, you MUST retune the two-stroke for the larger prop before passing judgement.

You could cut a notch in the firewall to accept the carburetor that projects rearward from the four-stroke engine. You won't need as large a fuel tank for a four-stroke engine, so the rear projecting carb won't be a problem when it interferes with the fuel tank. Get a smaller fuel tank.

I'm not familiar with the trainer that you are flying. The above advice was meant for a model that utilized wooden crutch bearer mounts. If your model uses a bolt on mount, simply buy one that fits the four-stroke and fit her up. Good luck.


Ed Cregger

Hi!
The OS LA series of engines are dead reliable!!!
Use 5-10% Nitro fuel.
OS 8 or Enya 3 glow plug.
Use a 8-10oz tank (preferable set up with Uni-flow (two clunks)). Mount it according to the "tank mounting rule"!
Use a 11x6 or 12x4 APC or RAM prop.
And last...set the engine a little rich each time you fly!

...There you are!

If you follow these recommendations your OS.46 will run like tops!

&lt;meta content="text/html; charset=utf-8" http-equiv="Content-Type" />&lt;meta content="Word.Document" name="ProgId" />&lt;meta content="Microsoft Word 10" name="Generator" />&lt;meta content="Microsoft Word 10" name="Originator" />&lt;link href="file:///C:\DOCUME~1\Noel\LOCALS~1\Temp\msohtml1\01\clip_fi lelist.xml" rel="File-List" /><![if gte mso 9]><xml><w:WordDocument><w:View>Normal</w:View><w:Zoom>0</w:Zoom><w:Compatibility><w:BreakWrappedTables /><w:SnapToGridInCell /><w:WrapTextWithPunct /><w:UseAsianBreakRules /></w:Compatibility><w:BrowserLevel>MicrosoftInternetE xplorer4</w:BrowserLevel></w:WordDocument></xml><![endif]><style type="text/css"><! Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";}@page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;}div.Section1 {page:Section1;}></style><![if gte mso 10]><style> Style Definitions */table.MsoNormalTable{mso-style-name:"Table Normal";mso-tstyle-rowband-size:0;mso-tstyle-colband-size:0;mso-style-noshow:yes;mso-style-parent:"";mso-padding-alt:0in 5.4pt 0in 5.4pt;mso-para-margin:0in;mso-para-margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:10.0pt;font-family:"Times New Roman";}</style><![endif]><p class="MsoNormal">Ok guys here's a link from tower just to show which plane.<span style=""> </span>http://www3.towerhobbies.com/cgi-bin/wti0001p?&amp;I=LXCAS2&amp;P=FR<o></o></p><p class="MsoNormal">And I would post some pics to show the problem with mounting the FA56 If I could figure out how to upload the pic.<span style=""> When ever I click on insert image it just wants a url. </span>Anyway, the carb is on the back of the FA56 engine and completely in the way if the engine is mounted right side up or inverted it doesn't<span style=""> </span>change the fact that its still on the back of the engine.<span style=""> </span>Couldn't mount it inverted anyway on this plane as it would darn near touch the ground - not good on a hard landing.<span style=""> </span>If I could move the carb to any place except the back of the engine I'd be in business.<span style=""> </span>I'd have to move the engine at least 1 1/8 inch forward for the carb to clear the firewall.<span style=""> </span>Too far I think.<span style=""> </span><o></o></p><p class="MsoNormal"><o></o></p><p class="MsoNormal"><span style=""> </span>I dont have a problem changing the mount if necessary.<span style=""> </span>Hobbsy and Thumbskull : I see the two screws holding the carb but not sure what I'd accomplish.<span style=""> </span>Are you talking about getting the carb to be right side up instead of inverted - carb opening pointing up instead of pointing down as it comes from the factory?<span style=""> </span>Therefore getting the throttle on the other side?<span style=""> </span><o></o></p><p class="MsoNormal"><o></o></p><p class="MsoNormal">As for the problem with the LA - I hate to get into that again but suffice it to say it's been a PIA since the day I got it.<span style=""> </span>Broke in properly and runs ok on the ground now after a lot of tinkering with it, but that's where the joy ends.<span style=""> </span>I've never been able to run a full tank of fuel thru it in the air.<span style=""> </span>Studders and dies regularly and I've tried everything and frankly am at a loss so I don't want to mess with it anymore.<span style=""> </span>I'm sure some of it is my own inexperience, but for a beginner engine OS did poorly on this one.<span style=""> </span>Only thing the LA got me was a lot of practice landing dead stick.<span style=""> </span>Everyone at my club field advises that its crap and suggests I replace it.<span style=""> </span><o></o><o>
</o><o>
</o></p><p class="MsoNormal">Shaggy</p>

OK, its eazy peazy, get this engine mount and four 6x32 blind nuts and four 6x32 socket head screws. Don't use the wood screws that come with the mount. The .56 will fly your plane with ease in fact a Saito .40 will fly it.

http://www3.towerhobbies.com/cgi-bin...&I=LXJ772&P=ML

I'll be back. This is my .56 in an RCM 40, I get a little fancy with the throttle. You can just run a wire out past the carb and bend it 180 back to the carb and it will work just fine.

Many people confuse HP with thrust. A Saito 56 will have plenty of thrust for that airframe.
You could put a 3 horsepower pylon engine on there and get less thrust than a 56 Saito.
The Pylon engine uses RPM to get high HP numbers with a small prop.
The Saito 56 will use a large prop to give a low HP number but will have greater thrust.

The OS LA engines have a problem with air leaks thru the plastic engine back plate. Remove the back plate and put sealer around the perimeter of the mounting area and then re-install the back plate.

Thumbs, I like to call that, "flyin Power" and it will surprise you over paper HP any day of the week.

Thanks Hobbsy I may need a different mount to use the 56. I do have a saito mount on the way. If that one doesn't work I may try the one you've posted from tower. I'm putting together a list of stuff I need to order from tower any

NM2K you may be right about the 56 not being more powerful. But I do think it'll fly the tower 40 just fine and yes I could cut the firewall to allow the carb to clear but it seems an unreasonable approach. I'd be better off just getting a better 2 stroke.

Sorry Jaka - I wont dispute your learned opinion - But I've tried all that with this LA 46 and it just doesn't meet the standard you claim nor my patience.

Shags, my RCM 40 is nearly identical to your plane in the spec department. The RCM has a 63" span. I have flown it quite a bit with an old Saito .40 and a Graupner 12x5, I've also flown it with a Saito .62 and a Graupner 12x7, with the .62 it will do loops where it is nearly out of sight at the top. I use a Graupner 12x6 or Bolly 12.5x6 on the .56. The reason for the side mount is it will get an LA .46 Diesel conversion next. The beauty of the GP mounts is limitless engine mounting possibilities.

Get a longer engine mount for a few dollars and throw that Saito in her, should be easy peasy. You will certainly enjoy the flying alot more when listening to that beautiful music the fourstroke makes instead of that annoying weeeeeee.... sound of the twostroke.

I swap my engines around alot, never seem to decide which I like the best. After flying a twostroke in a certain plane for a while, I swap it out for a fourstroke, and after a while again I swap that one for another twostroke and................on and on

I always use the stock mounts that come with the planes and drill holes to fit both two and fourstrokes. All it takes is to move the fourstrokes a little forward and re-route the throttle linkage some. No big a deal really

The Saito probably weighs slightly more than the LA. That and the fact that the Saito mount will put the engine forward enough to clear the firewall means you may need to move the receiver battery to get the CG correct. If you use one of the plastic mounts it will save some weight up front.

You are correct Carrellh. The saito does weigh more and moving the engine forward will be a concern to get the CG right. I'll definately have to move the battery around to get it right.

Hobbsy: I may just go ahead and order that mount thanks. Only difference seems to be the tower has those two side walls instead of just a flat front.

Asmund - I agree. I've gotten the Saito 4-stroke bug at that moment. I have a Saito 100 in an Aeroworks 60 size Yak 54 and I'm loving it. Sounds sweet , and starts and runs reliably every time. I want that kind flying on the old trainer. Here's pic of the yak before I put the decals on.



Shaggy

More horsepower makes more thrust every time, when the proper propellers are chosen. I said in my post to mount the four-stroke's large prop on the OS .46LA and watch it out turn the four-stroke, which will provide the same or more thrust.

If you're a mild type of flyer that floats around at half throttle most of the time, you might not notice the difference in power between similarly sized two and four-strokes. You could even begin to believe that the four-strokes better throttle response makes it a stronger engine You could, because after all, your model is already grossly overpowered. But when it is time to takeoff from a dew moistened wet grass field, the extra power provided by a two-stroke of near the same displacement will impress you. Just do what I do - use a larger four-stroke! <G>


Ed Cregger

Something is wrong with either your OS .46LA, the model's fuel tank mounting or the tank assembly. One or all are at fault. The preceding depends upon your fuel being proper, all of the screws on your engine being tight and all of the potential air leaks being sealed on your engine.

You will not win the arguement with me or anyone else on this forum about the OS .46 LA's suitability or reliability. If your engine is as problematic as you say, you should have sent it back a long time ago and have the warranty folks give it a good going over.

I explained what could cause your engine to run poorly some time ago. I explained that the fuel tank needed to be vibration proofed. Or, if you wanted to find out if that was really the problem, to squirt a drop or two of Armor All into your fuel. Did you do that? My guess is no, or you wouldn't be back here making the same complaints.

Oh, this is a technical hobby. There is no way to participate in this hobby without becoming technically oriented and willing to experiment to find a viable solution.

Good luck to you in our hobby.


Ed Cregger

Just for the record - Nowhere did I suggest that your Saito .56 would not fly your model satisfactorily.

The two-stroke you have is just fine. If the problem is where I think it is (vibration bubbling your fuel), a new two-stroke would not perform any better.


Ed Cregger

Ed,

Here is just one example where more HP does NOT equal more thrust.
Case 1 is Saito 56 and Case 2 is a pylon engine at nearly twice the HP but less thrust.

Are you for real?


Ed Cregger

You know, I said at the beginning that I didn't want to make this post about my OS46 LA. But that seems to be the direction it has gone, I think because of my dissatisfaction with that engine. But my post was about replacing it with something I would consider an upgrade, i.e. the saito 56. Still, I responded to the querry about the LA, but I did not come on here to complain about it. Because as I said before I'm done messing with it. As far as I'm concerned that would be like beating a dead horse - just no point to it. So you can get your panties all in a knot if you want to because you don't like my "complaining" as you put it. But you wont convince me that the one I have is little more than a cheap crappy engine.

I want to fly not tinker. And the only experiment I want to do at this point is replace it. If I were a betting man, I'd bet you a 100 to one that a new engine will mount in this airplane with no other modifications other than break in and mounting and will run reliably no problem. And I wont have to put armor all in the fuel nor put sealant around the back plate either. But again I digress... and there's little point to it.

I'll mount up the saito when I get the mounting sorted out and let you know how my little experiment goes.

shaggy

Go Saito...

HooRah!!!!

he just wants something better than the 2 stroker. some of you guys just missed his point, didnt even hit the backstop.

I have three Saito 56's and a couple 62's. They are wonderful and trouble free. Had one 56 about 12 yrs, One 10 yrs and another 5 yrs.

Get the saw and knife busy. Install the 56. There is no replacement for displacement. You won't be disapointed.