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Aug 20, 2019, 03:37 PM
Registered User
Oh - and the Magnum XLS .15 is a pretty nice engine, too.

Not the XL, the XLS. I don't know much about the XL, but I have an XLS, and it's a nice machine.
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Aug 20, 2019, 03:50 PM
A man with a plan
Balsaworkbench's Avatar
Quote:
Originally Posted by RC Man
I wonder if taking the baffles out of the muffler would get me more power. Has anyone tried that with that type of OS muffler.
The OS 10 and 15 FP share the same muffler, which was supplied with a very effective baffle. You can barely hear the engine when it's running. You could make a pretty good case that this muffler is too small for the 15. I always thought these engines were too quiet, so I run my engines without the baffle, which is also an easy way to get a power boost from both engines.

The 15 FP is significantly more powerful than the 10 FP. These engines are favorites of mine. The 10 has very good handling, it starts easily, it idles dependably, etc. It's also just cute. The 15 FP is also a really nice engine with equally good handling, easy starting, etc.

Whatever you like about the 10, you'll notice that the 15 has the same qualities. The 15 FP has one quirk I'm not crazy about. It has a funny metric size propeller shaft that doesn't match the rest of my OS engines. But it's no big deal.
Aug 20, 2019, 04:03 PM
A man with too many toys
Thread OP
Quote:
Originally Posted by Balsaworkbench
The OS 10 and 15 FP share the same muffler, which was supplied with a very effective baffle. You can barely hear the engine when it's running. You could make a pretty good case that this muffler is too small for the 15. I always thought these engines were too quiet, so I run my engines without the baffle, which is also an easy way to get a power boost from both engines.

The 15 FP is significantly more powerful than the 10 FP. These engines are favorites of mine. The 10 has very good handling, it starts easily, it idles dependably, etc. It's also just cute. The 15 FP is also a really nice engine with equally good handling, easy starting, etc.

Whatever you like about the 10, you'll notice that the 15 has the same qualities. The 15 FP has one quirk I'm not crazy about. It has a funny metric size propeller shaft that doesn't match the rest of my OS engines. But it's no big deal.
My 10 FP is a very sweet running engine. And I agree that the muffler is almost too quiet.

I will have a look and see how I can easily mod the muffler. Looks like the design I have you can't actually remove the baffle.

I will also keep an eye out for a NOS or good used 15 FP. How much wider is the 15 crankcase compared to the 10? It's hard to find specifications on those old engines.

.
Aug 20, 2019, 04:17 PM
A man with too many toys
Thread OP

Enya 15cx


What is that engine is it any good?

Looks kike it is BB, is it a heavy engine?

Does anyone own one?
Aug 20, 2019, 04:45 PM
Registered User
Try that 7x4 prop, it might wake the .10 enough to pull your plane through basic aerobatics well enough to please you. If that doesn't work, Tower lists the OS 15LA, which should make more power than your 10 FP and be a little heavier.
Aug 20, 2019, 05:19 PM
A man with too many toys
Thread OP
APC 7x4 props are hard to find locally. I hate to order a $2 prop and pay $5 for shipping. I will probably wait until I have a reasonably sized order.

.
Aug 20, 2019, 05:31 PM
A man with a plan
Balsaworkbench's Avatar
Quote:
Originally Posted by RC Man
My 10 FP is a very sweet running engine. And I agree that the muffler is almost too quiet.

I will have a look and see how I can easily mod the muffler. Looks like the design I have you can't actually remove the baffle.

I will also keep an eye out for a NOS or good used 15 FP. How much wider is the 15 crankcase compared to the 10? It's hard to find specifications on those old engines.

.
Which muffler do you have? The standard muffler on these engines is the 871. It looks like the baffle is an integral part, but that's only because the machining is so precise. If you take the screw out of the middle, the baffle comes right out.

I measured the crankcase width on my 10 and 15 FP.

The 15 has the baffle in the muffler, so it could be removed for a loss of a fraction of an ounce.

10 FP: 5.4 oz, 23 mm (29/32")

15 FP: 6.6 oz, 25 mm (63/64")

I tried to shoot the photos from directly overhead, but they look almost the same size because of lens distortion and perspective.
Aug 20, 2019, 05:37 PM
Registered User
You can drill out the outlet of your existing muffler for a bit more power. I opened up the baffle on my versions of the muffler on the lathe. I made a thinner shim for the head, and it picked up some power too. You would want around .010" head space to the piston if you like to fiddle with those things. I kind of forget which .10 was which. FP or LA. As previously mentioned, no muffler is needed, depending on the club field. All the previously mentioned motors are fine but will require a different mount in most cases. There is also an AP .15 rear exhaust which has a restrictive muffler but it may have slightly more power than the .10. It is not made any more either. There was a Fox .15 BB which was OK too. I would stay away from a slant plug Fox .15 and the Thunder Tiger .15. Very little power. They are ok, but why bother? To go new, it is pretty much an LA .15 or Norvel as everything else is not produced any more unfortunately.
Aug 20, 2019, 06:24 PM
A man with too many toys
Thread OP
I have the long muffler. I just got done working on it.

The exit pipe had a smaller hole on the inside than on the outside. Not sure if that was suppose to be that way. I drilled the whole thing as large as I could.

The baffle was drilled out to 3/8". More than double the area of the original hole.

I got rid of the rubber exhaust deflector tube (see above photo). Not sure if those things increase back pressure or not.

Next time I will re-tune the engine as there might be a change in muffler pressure that will change the mixture. I will continue to run the same 15% fuel because that's all I have at this time. I will check the balance on my APC 7x5 prop and give it a go. Too bad that I did not take a baseline RPM reading first.

The performance was plenty to do loops from level flight but I could hear the engine bog down and see the airplane slow down as it reached the top of a big loop. My biggest complaint is the slow climbout when I hand launch.

.
Aug 20, 2019, 07:07 PM
A man with a plan
Balsaworkbench's Avatar
That original baffle hole is ridiculously small, isn't it? I'm surprised the engine runs at all with the original setup. You should notice a difference.

You also may find that a lower pitch prop helps a lot.
Aug 21, 2019, 01:28 AM
Registered User
surfer_kris's Avatar
I really like my .10FP with the stock muffler. It provides a lot of pressure to the fuel tank and that's what makes the engine so reliable. Even at idle I can point the nose of the plane straight up and the engine doesn't miss a beat.

The APC 7x5 is about the maximum prop load though, and I've added an extra head shim for that prop on 10% nitro fuel (and 20% all castor). It does about 14100rpm on the ground when set slightly rich for good in air performance. On the APC 7x4 it will make about 15800rpm and the extra head shim is not needed. I prefer the 5" prop pitch though, it gives a better performance at lower throttle settings.

It sounds to me like your plane is simply too heavy, 33oz is a lot to ask for from a .10 engine. Even my .15 planes are less than that. With a modern radio and battery we can do much better than that these days.

Here is what I have my .10FP engine in, it has a 33" wingspan and weights about 23oz (as shown with the landing gear);
Last edited by surfer_kris; Aug 21, 2019 at 04:54 AM.
Aug 24, 2019, 03:23 AM
Registered User
If you don't mind a diesel, PAW in England still make smaller engines new. I have and have had in the past , PAW engines and they are very easy to handle and, contrary to all the urban myths, they throttle well. If they didn't PAW wouldn't offer them with carburettors from new. They also mean you can travel light as there are no electrics required to start them, they smell gorgeous and sound so special.

Cheers,
Martin
Aug 24, 2019, 05:06 AM
A man with too many toys
Thread OP
I have run diesels before but I don't know if fuel is available in the US?
Aug 24, 2019, 08:01 AM
WBE
WBE
White Fang
WBE's Avatar
Diesel is available but here’s your solution. They’re on sale at novarossidirect.com. $192 AFTER the 45% discount. What’s not to love?
Aug 24, 2019, 03:48 PM
Registered User
surfer_kris's Avatar
Quote:
Originally Posted by WBE
What’s not to love?
The weight and the price...

But the build quality and performance are both top notch.

For the shown plane a weight reduction should be number one on the priority list. A larger heavier engine will likely just turn it into a flying brick.


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