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Boosting power output in this small engine...??

Old 09-20-2010, 07:01 PM
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CGCINC
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Default Boosting power output in this small engine...??



I have an O.S. 40LA that I am installing in a plane this weekend.
I'm wondering if there are any aftermarket products to help increase the hp output?

Tuned Exhaust?
Carb?
Little tricks?

How much Nitro is safe in these?

Old 09-20-2010, 07:11 PM
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summerwind
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Default RE: Boosting power output in this small engine...??

it's a good reliable engine just as it is.
try to keep it in the rpm range that OS designed it for.
in otherwords, if you try to spin it faster by adding more nitro and tuned exhaust, it'll end up being a paperweight.
plain bearing engine designs are designed to give good reliable power bands, but to some extent they will become vibraters too if overspun.
all the plain bearing engines i have had over the years were very good powerwise, but are not the brute killers like the AX, FX or the FSR series, but they are not too far off either..............the right fuel and right prop is the most important part of getting the most from your engine.
you are putting this on an Escapade right?

go with the prop that OS recommends for sport flying.
it's been a while, but i think an 12x4 would be a good start, or maybe a 11x6

it'll fly that plane just fine, but you won't see unlimited vertical, but it will fly it well enough you can keep advancing with the combination.
Old 09-20-2010, 07:54 PM
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Default RE: Boosting power output in this small engine...??


ORIGINAL: summerwind

it's a good reliable engine just as it is.
try to keep it in the rpm range that OS designed it for.
in otherwords, if you try to spin it faster by adding more nitro and tuned exhaust, it'll end up being a paperweight.
plain bearing engine designs are designed to give good reliable power bands, but to some extent they will become vibraters too if overspun.
all the plain bearing engines i have had over the years were very good powerwise, but are not the brute killers like the AX, FX or the FSR series, but they are not too far off either..............the right fuel and right prop is the most important part of getting the most from your engine.
you are putting this on an Escapade right?

go with the prop that OS recommends for sport flying.
it's been a while, but i think an 12x4 would be a good start, or maybe a 11x6

it'll fly that plane just fine, but you won't see unlimited vertical, but it will fly it well enough you can keep advancing with the combination.
10-6 to 11-6 is for sport and I've got both sizes. Also have a 12-6. Yes, this is for an Escapade.
I've got a gallon of 10% nitro... Is that good enough?
Old 09-20-2010, 08:02 PM
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Default RE: Boosting power output in this small engine...??

I've tinkered with them (muffler modification) and gotten more RPM but you can pay a penalty in longevity if you aren't careful. I agree that leaving it as-is is the best choice. The Escapade is not a large airplane so the .40 will fly it fine for sport aerobatics and stuff.

That being said, it is your engine to do with as you please and have fun. I would just run it as-is first if it were mine though.
Old 09-20-2010, 08:06 PM
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Default RE: Boosting power output in this small engine...??


ORIGINAL: ChuckW

I've tinkered with them (muffler modification) and gotten more RPM but you can pay a penalty in longevity if you aren't careful. I agree that leaving it as-is is the best choice. The Escapade is not a large airplane so the .40 will fly it fine for sport aerobatics and stuff.

That being said, it is your engine to do with as you please and have fun. I would just run it as-is first if it were mine though.

I don't want to screw it up. I just know they make different exhausts and things for Nitro cars/trucks so I just figured they would for planes.
I would guess if you pull the baffle out it would make less power?? Probably needs the back pressure...
I'll fly it as is and just see how it does.

What's the optimum Nitro mixture for these little engines?
Old 09-20-2010, 10:05 PM
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Default RE: Boosting power output in this small engine...??

the engines that pipes are made for are most always ball bearing supported crankshaft, and intake and exhuast timing plays a part with extracting even more power from them.
seriously though, you'll be more than happy with your combo.
taking the baffle out and drilling the exhaust hole does give you a bit more, but remember, the LA engines aren't design to be spun faster.

go out and have fun with this setup.

oh and anymore weight needed to balance can be had with a heavy prop nut like this,

http://www3.towerhobbies.com/cgi-bin...?&I=LXL729&P=7


15% is what i would call max.......just buy the brands that have Castor in the mix too.
Old 09-20-2010, 10:23 PM
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Default RE: Boosting power output in this small engine...??

For non-ringed engines I've always started low 5-10% then as it starts to wear and you start to notice power reductions you can go up in % nitro. This should take years though, less if you fly a lot, as long as you take care of your engines. Now I am not an engine expert, but this has always worked for me.
Old 09-20-2010, 10:28 PM
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Default RE: Boosting power output in this small engine...??


ORIGINAL: summerwind

the engines that pipes are made for are most always ball bearing supported crankshaft, and intake and exhuast timing plays a part with extracting even more power from them.
seriously though, you'll be more than happy with your combo.
taking the baffle out and drilling the exhaust hole does give you a bit more, but remember, the LA engines aren't design to be spun faster.

go out and have fun with this setup.

oh and anymore weight needed to balance can be had with a heavy prop nut like this,

http://www3.towerhobbies.com/cgi-bin...?&I=LXL729&P=7


15% is what i would call max.......just buy the brands that have Castor in the mix too.
That's a serious nut!! lol...
So since I'm new to Nitro I'll ask this question.......
What happens when you fly and run the tank lower and lower? Does it become nose or tail heavy OR is the tank mounted so it splits the CG and it nothing happens?
Old 09-20-2010, 11:53 PM
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summerwind
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Default RE: Boosting power output in this small engine...??

balance the model with an empty tank, and this applies to a tank that is on or forward of the CG.
beginning of the flight will be nose heavy when the tank is mounted right behind the engine (as it should in this case) and of course as it burns fuel off, it will still be stable. unless you are using some monster sized tank (way bigger than normal) you'll not notice the shift.

remember something important though in that setting the High speed needle is best done with just over half a tank, and set the needle so that it is on the rich side after finding peak. when tanks run down the engine will tend to lean out. check it with a full tank too, but if it only richens up slightly more than it was set with half a tank, then leave it there.
i see people setting an engine for peak with a full tank only to end up with an engine going lean at the end of a tank.
a little smoke at top speed is your friend...........not a lot, just a tad.
you have help where you fly?
Old 09-20-2010, 11:55 PM
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Default RE: Boosting power output in this small engine...??

open the carb up, raise the exhaust timing to 163 degrees and put on a Jett muffler. run a 11x5 prop and it will pull that plane very well.
Old 09-21-2010, 09:00 AM
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Default RE: Boosting power output in this small engine...??


ORIGINAL: airraptor

open the carb up, raise the exhaust timing to 163 degrees and put on a Jett muffler. run a 11x5 prop and it will pull that plane very well.
This sounds good but I have no clue how to do it...
Old 09-21-2010, 09:03 AM
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Default RE: Boosting power output in this small engine...??


ORIGINAL: summerwind


you have help where you fly?
Yes, I can get help if needed. I don't know too many at the field but they are all nice and willing to help!
I have the engine set, with a half tank of fuel, on the engine stand so it should be close when I get it installed.
I ran it to peak rpm and then richened it just a 1/4 turn. It blows light smoke and a lot more fuel than I thought it would.
Old 09-21-2010, 10:09 AM
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Default RE: Boosting power output in this small engine...??

For the O.S. Max .40 LA, any 12" prop would be too much! A 10 x 5, 10 x 6, 11 x 5, maybe even a 9 x 8 in some cases. You want the engine to turn in the mid-to-high-11,000's on the ground when at full throttle and leaned to just rich of peak RPM. Use a fuel with 5%-10% nitro for best results, and make sure the fuel has no less than 18% oil content in a synthetic/castor oil mix. The more castor oil in the oil mix, the better.

Many times, large propellers are recommended simply to help reduce any noise level, but you'll pay for it in much-reduced power from the engine. If you don't have a particular requirement for low noise levels, Let 'Er Rip! You'll find the engine will run well and thank you for letting it run free!
Old 09-21-2010, 12:15 PM
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Default RE: Boosting power output in this small engine...??


ORIGINAL: Bax

For the O.S. Max .40 LA, any 12" prop would be too much! A 10 x 5, 10 x 6, 11 x 5, maybe even a 9 x 8 in some cases. You want the engine to turn in the mid-to-high-11,000's on the ground when at full throttle and leaned to just rich of peak RPM. Use a fuel with 5%-10% nitro for best results, and make sure the fuel has no less than 18% oil content in a synthetic/castor oil mix. The more castor oil in the oil mix, the better.

Many times, large propellers are recommended simply to help reduce any noise level, but you'll pay for it in much-reduced power from the engine. If you don't have a particular requirement for low noise levels, Let 'Er Rip! You'll find the engine will run well and thank you for letting it run free!
A Master Airscrew 10X6 always seemed to be the best overall prop for the 40LA for me. It doesn't bog the engine RPMs down yet won't let it overspeed either.
Old 09-21-2010, 01:31 PM
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Default RE: Boosting power output in this small engine...??

A simple way to boost power on these sport engines is a mousse-can pipe. The 3D guys have been using them for years. Type "mousse-can pipe" into a search engine and you will see plans and a detailed explanation. I have them on several engines and have always been pleased and impressed by the power boost they give without affecting the idle or general characteristics.
Old 09-21-2010, 01:58 PM
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Default RE: Boosting power output in this small engine...??


ORIGINAL: Lifer

A simple way to boost power on these sport engines is a mousse-can pipe. The 3D guys have been using them for years. Type "mousse-can pipe" into a search engine and you will see plans and a detailed explanation. I have them on several engines and have always been pleased and impressed by the power boost they give without affecting the idle or general characteristics.
Hmmmmmm..... That's an easy try. Thanks!!
Old 09-21-2010, 02:03 PM
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Default RE: Boosting power output in this small engine...??


ORIGINAL: Bax

For the O.S. Max .40 LA, any 12'' prop would be too much! A 10 x 5, 10 x 6, 11 x 5, maybe even a 9 x 8 in some cases. You want the engine to turn in the mid-to-high-11,000's on the ground when at full throttle and leaned to just rich of peak RPM. Use a fuel with 5%-10% nitro for best results, and make sure the fuel has no less than 18% oil content in a synthetic/castor oil mix. The more castor oil in the oil mix, the better.

Many times, large propellers are recommended simply to help reduce any noise level, but you'll pay for it in much-reduced power from the engine. If you don't have a particular requirement for low noise levels, Let 'Er Rip! You'll find the engine will run well and thank you for letting it run free!
YEP, and good ol Bax will hide in the closet when you burn it up and send it in for warranty repair..........
the bottom line is that OS, or Hobbico should add an adendum to their instructions telling users this.................
Old 09-21-2010, 03:38 PM
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Default RE: Boosting power output in this small engine...??

Well, I got bored today at work and decided to clean things up a bit.... if it doesn't go fast, it's gotta look good!!
A little sandpaper and Mothers always works!
I tried not to take off too much material....Only camera I have here is my cell phone so it's a bad picture.

Old 09-21-2010, 07:13 PM
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Default RE: Boosting power output in this small engine...??

Smoother surface=less drag.

Probably not really in this case but it will look cool.
Old 09-21-2010, 07:50 PM
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Default RE: Boosting power output in this small engine...??

I've been using 15% Omega in my two strokes and it has served me well. I'm told it has about 17 % oil mix with about 10 % castor and the rest synthetic. Adding a couple oz of castor per gallon won't hurt at all either, especially in that .40 La which does not have bearings or ringed pistons. I use "Klotz" castor in mine, but any brand you can get will probably do. I'd also start with a 10 x 6 Mas prop and O.S. #8 or equal glow plug. The A-3 plug might give you better performance, and will start better in cold weather, but the #8 will last longer and be more tolerant to accidentally lean mixtures while you are learning how to tune your engine.
Old 09-21-2010, 09:25 PM
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Default RE: Boosting power output in this small engine...??


ORIGINAL: hugger-4641

I've been using 15% Omega in my two strokes and it has served me well. I'm told it has about 17 % oil mix with about 10 % castor and the rest synthetic. Adding a couple oz of castor per gallon won't hurt at all either, especially in that .40 La which does not have bearings or ringed pistons. I use "Klotz" castor in mine, but any brand you can get will probably do. I'd also start with a 10 x 6 Mas prop and O.S. #8 or equal glow plug. The A-3 plug might give you better performance, and will start better in cold weather, but the #8 will last longer and be more tolerant to accidentally lean mixtures while you are learning how to tune your engine.
I've got a handful of #8 glow plugs and the prop that's on it now is a 10x6, the engine sounds better(more rpm's I guess)with this one compared to the 11x6 I have.
I was looking at my fuel today and I can't remember exactly, but I think it had 22% Castor oil content?!?!? It was a cheap ($16.99) gallon of 15% nitro fuel at the local hobby store.
Old 09-22-2010, 01:35 PM
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Default RE: Boosting power output in this small engine...??

New question:

I pulled the baffle out of the exhaust today and ran it. It sounds Mean and seems like it has more thrust just by my hand being behid it.....Maybe not though.
Will this hurt the motor?
Will it give any more power?

I don't have a way to check rpm's but it sounds like it increased slightly. Since everyone says don't spin the motor out of its operating range, would it help to go from a 10x6 prop to an 11x6 to lower the rpm's? AND, would that do anything as far as thrust or speed?

Old 09-22-2010, 01:58 PM
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Default RE: Boosting power output in this small engine...??

All I have ever ran in the LAs is Power Master 15-18 and my LAs have had gallons of fuel ran through them without wearing out. I'm not big on adding anything to my fuel. If I need more oil then I buy the blended fuel I need. I had always pulled the baffle but really never noticed any power jump by doing so. This was just talked about this weekend at the field this weekend, props on the 40s. Seems most people lean towards the APC 10-6 on the .40 and the 11-6 on the .46. A longer prop with a smaller pitch will give you more torque with less speed and the shorter prop with a bigger pitch will give you more speed and less torque. On the .40 you can do some prop testing to find the prop that will fly the plane the way you like, there is no one perfect prop for any plane or engine. You must do the testing to find what you the pilot likes. With a 10 or 11 inch prop you won't over rev your engine. Down the road you will require a voltage testor, it's one of the must have items in your flight box. Horizon has one that is a combo volt meter/tach. I have tested several of them against my good TNC Tach and so far they have all been on the mark. A two in one tool, give it some thought but a tach isn't something most people need right away. {or ever} I work on a lot of engines so I have a good one but it is over kill for most weekend pilots.
Old 09-22-2010, 03:56 PM
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Default RE: Boosting power output in this small engine...??


ORIGINAL: Gray Beard

All I have ever ran in the LAs is Power Master 15-18 and my LAs have had gallons of fuel ran through them without wearing out. I'm not big on adding anything to my fuel. If I need more oil then I buy the blended fuel I need. I had always pulled the baffle but really never noticed any power jump by doing so. This was just talked about this weekend at the field this weekend, props on the 40s. Seems most people lean towards the APC 10-6 on the .40 and the 11-6 on the .46. A longer prop with a smaller pitch will give you more torque with less speed and the shorter prop with a bigger pitch will give you more speed and less torque. On the .40 you can do some prop testing to find the prop that will fly the plane the way you like, there is no one perfect prop for any plane or engine. You must do the testing to find what you the pilot likes. With a 10 or 11 inch prop you won't over rev your engine. Down the road you will require a voltage testor, it's one of the must have items in your flight box. Horizon has one that is a combo volt meter/tach. I have tested several of them against my good TNC Tach and so far they have all been on the mark. A two in one tool, give it some thought but a tach isn't something most people need right away. {or ever} I work on a lot of engines so I have a good one but it is over kill for most weekend pilots.
I like to know whats going on so I probably will get that in the near future...$45 isn't bad compared to everything else.
I definitely like the sound coming from my little .40!!!

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