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Author Topic: Best tube muffler for LA-46?  (Read 1516 times)

Offline Scott Richlen

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Best tube muffler for LA-46?
« on: September 11, 2021, 07:42:59 PM »
Replaced heavy stock muffler with tongue muffler on my LA-46.  Plane flies much better having lost the muffler weight, but engine doesn't seem to run as stabily.  What is the lightest tube muffler for the LA-46 that still keeps the engine running correctly?

Online Brett Buck

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Re: Best tube muffler for LA-46?
« Reply #1 on: September 11, 2021, 08:32:25 PM »
Replaced heavy stock muffler with tongue muffler on my LA-46.  Plane flies much better having lost the muffler weight, but engine doesn't seem to run as stabily.  What is the lightest tube muffler for the LA-46 that still keeps the engine running correctly?

   The one that came with it.

    Brett

Online Tom Luciano

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Re: Best tube muffler for LA-46?
« Reply #2 on: September 12, 2021, 05:52:19 AM »
Scott,
  Al ferraro grounded alot of weight of the stock muffler and polished it up. Was quite pleasing to the eye and cut a tremendous amount of weight.

He posted a picture somewhere on here

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Offline Dan McEntee

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Re: Best tube muffler for LA-46?
« Reply #3 on: September 12, 2021, 07:01:50 AM »
  A Scott Dinger muffler works well with the LA.46 and only weighs 1/2 to 3/4 ounce.. A muffler from a Tower Hobbies .40/46 fits and is much lighter than stock OS and is about the same dimensions. I don't know if Randy Smith is still making his tube muffler but they are quite light. Enya muffler from their recent .30 and .35 engines fit are lighter than stock OS units also but I have not run one. There was a recent thread regarding the Enya unit.
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Offline Joe Gilbert

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Re: Best tube muffler for LA-46?
« Reply #4 on: September 12, 2021, 07:18:52 AM »
Scott I have had goos results with a Fox 35 stock muffler. Have used Dinger tube mufflers on Tiger 60s with good results. They are very light.

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Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #5 on: September 12, 2021, 10:34:08 AM »
Thanks for the recommendations guys!

Quote
   The one that came with it. 

Ummmm, well, thanks!  I guess that's a solution.  But wouldn't that put me back where I started from?   :P

So, not really an effective solution wouldn't you think?  Since this isn't really about a tuned-pipe effect and more about chamber volume and exit area, I would hope that a muffler with the same properties (without the endearing boat-anchor quality) could be found.  So, with the many other recommendations I guess I'll have to sort through them.

However, Brett, I have a question that you could help me with: what size belcrank did you use in your Skyray?

 

Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #6 on: September 12, 2021, 11:51:13 AM »
Quote
A few numbers. These all fit the LA 46

OS  E 3030 - 84g
OS  843      - 75g
OS  843 with all extra metal removed - 62g
Silverline 40  - 62g 

Lots of options.  Thanks!

Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #7 on: September 12, 2021, 02:55:44 PM »
I want to post this note from Dan as some of you may be able to use the info for your LA-46:

Quote
   Hi Scott;
    Here is a group shot of muffler that fit the OS .40 FP, LA and .46 LA.  The middle one is the Tower muffler I was talking about, a full ounce lighter than the OS 3030 and this one doesn't have the cone/baffle in it. The 843 can be made a lot lighter with some grinding work. The 762 can be the real sleeper at only 1.7 ounces. The one at the bottom is an unkown, it has no markings and was just in my muffler box. Tower engines sometimes used a muffler identical to the OS.843. Keep your eye out at swap meets and such for any and all of these. I forgot to put the Enya in the picture, and it comes in at 1.5 oz./41gms, but like I mentioned it has a pretty small stinger and is shaped like the 762 but a bit smaller overall. The 762 might be easier to find and can be made as light as the Enya with some grinding. If you know how to post pictures to the forum and want to post this pic feel free to do so. I just don't know how to do all that techie crap!!

   Good luck,
   Dan McEntee 

Thanks Dan!

Offline Dan McEntee

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Re: Best tube muffler for LA-46?
« Reply #8 on: September 12, 2021, 05:07:04 PM »
The one I left off that photo was the Enya. It weighs 1.5 ounces  (approx.47 grams I think). It fits the LA/FP .40 and 46 and is smaller than the 762, but it also has a smaller exit stinger and the inlet is pretty small.
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Offline Tim Wescott

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Re: Best tube muffler for LA-46?
« Reply #9 on: September 12, 2021, 06:40:02 PM »
So, are you (A) replacing the nasty heavy stock muffler with a tongue muffler and re-balancing the plane to the came CG and noticing an improvement, or are you (B) replacing the nasty heavy stock muffler with a tongue muffler and not changing anything else and noticing an improvement?

Because if it's (B) -- an ounce or two difference in the plane weight isn't going to make nearly as much difference in performance as shifting the center of gravity.  If the CG is too far forward and you change the "weight of the plane" in a way that changes the CG and you see an improvement -- you're seeing an improvement in the location of the center of gravity.

Put the E3030 back on, then toss a quarter of an ounce of weight in the tail.  See if it flies better or worse than with the E3030 and no weight in the tail.  If it's better with 1/4 ounce of weight, try 1/2 ounce.  Keep that up until the CG is right -- heavy and flying right is better than a feather that won't corner or won't track.

Note: I'm lucky in that I have a couple of E3030 mufflers and a Tower 40 muffler.  If the plane is nose-heavy, it gets the Tower 40 muffler and as much weight in the tail as necessary to make it fly right.  If the plane is tail-heavy (my usual, cuz I'm horrible at light finishes) it gets an E3030, then as much brass, lead, depleted uranium, or whatever in the nose until it balances.  If the plane is nose-heavy and the Tower muffler is on another plane -- it gets weight in the tail until it flies right.
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Offline Joe Gilbert

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Re: Best tube muffler for LA-46?
« Reply #10 on: September 12, 2021, 06:47:47 PM »
A Fox 35 muffler weighs 48 grams. I know it is a Fox but try it anyhow or donít.
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Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #11 on: September 12, 2021, 06:55:26 PM »
Quote
  A Fox 35 muffler weighs 48 grams. I know it is a Fox but try it anyhow or donít.
 

Thanks Joe!  I'll have to look through my boxes and see if I have a Fox muffler.  Not sure I have one.

Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #12 on: September 12, 2021, 07:00:51 PM »
Quote
  So, are you (A) replacing the nasty heavy stock muffler with a tongue muffler and re-balancing the plane to the came CG and noticing an improvement, or are you (B) replacing the nasty heavy stock muffler with a tongue muffler and not changing anything else and noticing an improvement? 

None of the above.

(C) replacing the nasty heavy stock muffler with a tongue muffler and removing all of the tail weight needed to balance out the plane with the nasty heavy stock muffler.  Yields: lighter plane, less nose heavy plane, more powerful engine run.  Plane flies better, turns sharper, I just don't like the engine run.

Offline Tim Wescott

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Re: Best tube muffler for LA-46?
« Reply #13 on: September 12, 2021, 07:23:10 PM »
None of the above.

(C) replacing the nasty heavy stock muffler with a tongue muffler and removing all of the tail weight needed to balance out the plane with the nasty heavy stock muffler.  Yields: lighter plane, less nose heavy plane, more powerful engine run.  Plane flies better, turns sharper, I just don't like the engine run.

As long as you're not mistaking an improvement in CG for an improvement in weight, I'm good!

I'd still suggest a Tower 40 muffler as a good candidate replacement -- I don't notice a difference in the engine run with the Tower 40 muffler vs. the E3030, but it's quite a bit lighter.  If you go to swap meets, it might be something to keep an eye out for.
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Offline Dan McEntee

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Re: Best tube muffler for LA-46?
« Reply #14 on: September 12, 2021, 08:44:26 PM »
A Fox 35 muffler weighs 48 grams. I know it is a Fox but try it anyhow or donít.

     I knew that the Fox muffler fits, just was in a hurry to get the picture to Scott and didn't have one handy. They made those in a tilt up and a tilt down, which can come in handy at times, but don't understand why they didn't make one with a straight out stack?? The stinger can be drill out quite a bit and it is probably les restrictive than the OS 762. You just have to try it on your model to see how it works, and it just one piece of the puzzle that determines what your engine run is going to be like. The absolute lightest is the Scott Dinger muffler and I think they are 1/2 ounce. I didn't have one of these loose and handy either.
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Re: Best tube muffler for LA-46?
« Reply #15 on: September 12, 2021, 08:48:36 PM »
As long as you're not mistaking an improvement in CG for an improvement in weight, I'm good!

I'd still suggest a Tower 40 muffler as a good candidate replacement -- I don't notice a difference in the engine run with the Tower 40 muffler vs. the E3030, but it's quite a bit lighter.  If you go to swap meets, it might be something to keep an eye out for.

   The muffler I have in the photo didn't come with all Tower .40s, apparently. I have a couple more NIB Tower engines that have a clone of the OS 843 muffler, just doesn't have any numbers on it. The one at the bottom of the picture is of unknown origin. Does anyone recognize it? I don't know where I got it, but it fits the FP.35 and 40, and LA ,40 and .46. these all fit the OS .32 F and .32 SX also.
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Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #16 on: September 13, 2021, 06:51:28 AM »
Quote
   I'd still suggest a Tower 40 muffler as a good candidate replacement -- I don't notice a difference in the engine run with the Tower 40 muffler vs. the E3030, but it's quite a bit lighter.  If you go to swap meets, it might be something to keep an eye out for.

Thanks for the tip.  I'll see if anyone in the club has one.

Offline phil c

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Re: Best tube muffler for LA-46?
« Reply #17 on: September 13, 2021, 07:54:05 PM »
The stock LA mufflers make the 25, 40 and 46 run very well with a pleasant tone and less noise.
I put the 46 in a Smoothie with the 30-30 muffler and a half inch bigger stab/elevator.  It works fine.

Of course, if it really affects the plane you've got and it was already overweight then of course pick a smaller or lighter muffler.

Al Ferraro's idea of grinding excess weight off is another good approach.

Other things to keep in mind-  The outlet tube has a big impact on noise.  Open it up as a last resort.
The wall thickness of the various parts has a lot to do with absorbing sound. Generally the thinner and lighter the walls the more noise comes through.
The length of the body gives a tuned length of sorts for the sounds to bounce around in.
The thickness of the walls dampens transmitted sound.
The design of the innards gives the LA mufflers a multi baffle effect.  The offset inlet sets up some kind of rotary flow.  The cone baffle gives the exhaust another barrier.  Finally, the angled exhaust tube changes flow direction off of most fuselages.
I am pretty sure the OS engineer(s) tested all these different effects and came up with the present configuration.
From most reports the engine runs steadier with the muffler.  People want to save weight in pursuit of the last gram of excess weight.  The best place to do that is in the finish and materials selection!! 
One ounce ground off the muffler on a 50oz plane doesn't have much of an effect.  Losing a flying site because the "loud" exhaust does.
Since most folks seem to agree that the stock muffler seems to run the best don't modify it any more than necessary.
« Last Edit: September 15, 2021, 10:04:13 AM by phil c »
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Offline Crist Rigotti

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Re: Best tube muffler for LA-46?
« Reply #18 on: September 13, 2021, 09:44:10 PM »
I used a Ro-Jett tube muffler.  Very lite and high quality.

http://rojett.net/index.htm

http://www.rojett.net/products/headers_mufflers.htm

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Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #19 on: September 15, 2021, 05:47:19 AM »
Quote
  I used a Ro-Jett tube muffler.  Very lite and high quality.

http://rojett.net/index.htm

http://www.rojett.net/products/headers_mufflers.htm   

Are these guys still in business?  These look like pretty old pages.  I tried www.rojett,com and the site was for sale.  I also emailed to richard@rojett.com but have not received a reply.

Offline Tom McClain

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Re: Best tube muffler for LA-46?
« Reply #20 on: September 15, 2021, 06:39:47 AM »
Are these guys still in business?  These look like pretty old pages.  I tried www.rojett,com and the site was for sale.  I also emailed to richard@rojett.com but have not received a reply.

Call Dub Jett for Ro-Jett stuff.  He made all of it for Richard and he answers his phone and is very customer oriented.

Tom
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Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #21 on: September 15, 2021, 07:04:33 AM »
Quote
Call Dub Jett for Ro-Jett stuff.  He made all of it for Richard and he answers his phone and is very customer oriented.

Tom
   

Thanks Tom!  What's his phone number?

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Re: Best tube muffler for LA-46?
« Reply #22 on: September 15, 2021, 09:43:50 AM »
I tried www.rojett,com and the site was for sale.

Hi Scott,
Make sure to use a "period" instead of a "comma", not www.rojett,com but http://rojett.net/index.htm. Both links in the previous message worked for me.

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Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #23 on: September 15, 2021, 02:30:03 PM »
Quote
Hi Scott,
Make sure to use a "period" instead of a "comma", not www.rojett,com but http://rojett.net/index.htm. Both links in the previous message worked for me.

Dennis   

I just mis-typed it in my message.  I did go to both sites.  To order from the site it says to email richard@rojett.com

I did that.

Here's the message that comes back:

Delivery incomplete
There was a temporary problem delivering your message to richard@rojett.com. Gmail will retry for 45 more hours. You'll be notified if the delivery fails permanently.

I think that these are old webpages and no longer any good.

Offline Tom McClain

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Re: Best tube muffler for LA-46?
« Reply #24 on: September 15, 2021, 02:44:48 PM »
Thanks Tom!  What's his phone number?

http://dubjett.com

dubjett@gmail.com

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713-680-8113
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Offline John Carrodus

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Re: Best tube muffler for LA-46?
« Reply #25 on: September 15, 2021, 03:07:53 PM »
I have ground off the cooling fins from OS mufflers and painted them matt black. Saves a bit of weight without overheating problems. I have also mounted one on an OS 30 that had a smashed manifold mounting. I ground it off and mated the muffler straight against engine exhaust port. Made a good tight fit and also had no problem with overheating despite being told several times by various folk that I would. Out of desperation in finding spare exhaust chambers in the South Pacific, I have made my own for some time. Take aluminum tubing, hacksaw slits in the end, crimp the diameter down a few notches and insert a smaller diameter tube for the stinger. This can be welded in on an angle down or out from the model. Grind off the end either flat or angled out like a jet prop exhaust. Front end of tube can be welded closed, or believe it or not, far less messing about and works ( for years) plug with some hardwood dowel ( about 1 cm) long and drill through with very small drill and pin in place with stainless or piano wire. Use low temperature aluminum welding rods from an engineer supply shop. All you need is a small blow torch and the trick is the work has to be hot enough to melt the rod onto itself. Merely heating the rod melts it into blobs that roll off. Anyway you will get the idea after messing about a few times. Once you got it, it's like riding a bike. Cut/drill/file a slot to lip around the exhaust port and attach by drilling two holes for mounting bolts or if bolts can't be used, use wire and twist together around the cylinder, firmly but DO NOT OVERTIGHTEN. Allow enough for everything to expand , especially the outside of the cylinder as it heats up. Sometimes the wire needs slight retightening. But the exhausts work and can be stuffed at the tail end with large weave stainless steel wool. This must be retained at both ends with a fine wire pin through the stinger , and at the other end so as not to get too close to the port for obvious reasons. I have never had overheating issues ( I run 50/50 syn, caster oil) and usually paint them matt black which I'm sure helps dump heat too. Signed Heath Robinson! PS I will attempt to attach some photos below.

Offline Alexey Gorbunov

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Re: Best tube muffler for LA-46?
« Reply #26 on: September 16, 2021, 04:50:15 AM »
MACS muffler for OS-25FX.

Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #27 on: September 16, 2021, 07:11:24 AM »
Quote
  MACS muffler for OS-25FX. 

Who sells them?

Offline Alexey Gorbunov

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Re: Best tube muffler for LA-46?
« Reply #28 on: September 16, 2021, 07:19:25 AM »
Foto from MECOA site.

Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #29 on: September 16, 2021, 07:39:39 AM »
 1.353" (34.3mm) between mounting holes for OS-25FX muffler.

That's not going to fit.

Announcement on MECOA muffler page:
Most of these are not in stock and are discontinued.


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Re: Best tube muffler for LA-46?
« Reply #30 on: September 16, 2021, 08:14:22 AM »
Scott, check your PM. 
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Offline Alexey Gorbunov

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Re: Best tube muffler for LA-46?
« Reply #31 on: September 16, 2021, 08:14:36 AM »
OS25FX or OS25LA?

Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #32 on: September 16, 2021, 08:41:01 AM »
Status:

I am checking on the 40g Jett muffler and also reducing the weight of a stock OS 3030 (or is it a 3020?  I've ground the number off already... :D)

With the tongue muffler the plane flies fast level laps, but power falls off in the maneuvers and plane slows down.  Yesterday, trying it w/o the uniflow connected to the muffler results in the engine running progressively slower during the last half of the pattern.  Interesting.

Offline Dan McEntee

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Re: Best tube muffler for LA-46?
« Reply #33 on: September 16, 2021, 08:47:37 AM »
Status:

I am checking on the 40g Jett muffler and also reducing the weight of a stock OS 3030 (or is it a 3020?  I've ground the number off already... :D)

With the tongue muffler the plane flies fast level laps, but power falls off in the maneuvers and plane slows down.  Yesterday, trying it w/o the uniflow connected to the muffler results in the engine running progressively slower during the last half of the pattern.  Interesting.

   Scott;
   The .40/.46 is the 3030 muffler. The other one is for the LA.25. Nothing from any of the OS.25 engines will fit. you will be closer to what you need with the 843 muffler. It's lighter than the 3030 to start with. There are probably more of these out in the world than any of the others.
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Offline Steve Helmick

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Re: Best tube muffler for LA-46?
« Reply #34 on: September 16, 2021, 12:57:10 PM »
I've used the MACS Muffler on a .46LA and liked it, but it doesn't fit well on many planes with upright or inverted engines, as the wing is in the way. Fits great on a profile, but might be in the way of the LG. I had mine on a Humongus and put a little bend in the tailpipe to make it fit over the wing. Scott Riese did a bunch of promoting this pipe setup and said the launch rpm had to be 10,200 rpm. My experience showed that was good information, but would say perhaps 10k > 10.4k would get it working. When it's working, the engine sort of rattles like the muffler is falling off, but it isn't. It's hitting the right rpm in the air is all.

I found the 11.5 x 4 APC worked good on 10% nitro, but I also experimented with a cut down 12.25 x 3.75...to about 11.5" IIRC. I put that engine/MACS muffler on a Forerunner and flew it in Sparks, NV at 4,900' and it didn't work...couldn't get it up to 10,000 rpm. I had two options, run YS20/20 or change to a 10.5 x 4.5 APC, and chose the latter. It worked fine. That was 2007.

In 2009, I went to VSC with an ex-Don McClave short winged Skylark that I put the same .46 in, but with a Randy Aero CNC tube muffler. I had no complaints about the engine run quality with the 11.5 x 4 APC/10%, except that the tank was too small, even at Tucson's altitude. I changed to a .272" bore venturi (.156" spraybar) but it was still marginal. I had drilled out the exhaust tube bigger but also added a rubber ducky to deflect oil downward. I'd do that on a Classic again in a heartbeat. If Randy has those available again, that's a good muffler, but then you really need the rubber ducky and they're not light. The Jett muffler also needs a rubber ducky. The Scott Dinger muffler would not and is your lightest option. If you get ahold of Scott Dinger, ask about getting it polished and anodized...let him do it. No idea what the $$$ is for that optional extra. 

IMO, the OS .46 LA muffler is perhaps a bit restrictive. I've watched guys flying ARF Pathfinders using the stock .46 LA with the stock muffler and the "wonder prop", 12.25 x 3.75 APC. They ALWAYS seemed to be suffering from being either too lean or too much prop. Perhaps more nitro or bigger venturi would have helped, or maybe that "10%" was really back in the day of it being actually 7%. You can always put a sleeve in the exit to return it to stock size.

I used a stock .46 LA muffler on my Magnum XLS .36 and that was a sweet combination...but I also needed the nose weight. One option would be to use the Magnum .36 muffler on your .46...it is smaller and lighter, but might need to have the tailpipe opened up some.  D>K Steve

 
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Offline Phil Spillman

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Re: Best tube muffler for LA-46?
« Reply #35 on: September 21, 2021, 08:25:56 PM »
Hi Scott, Do try to see if Randy Smith has anymore of his tube mufflers! There very light, quiet and effective! These are the ones I use on my Humongous is OTS!

Phil Spillman
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Offline Al Ferraro

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Re: Best tube muffler for LA-46?
« Reply #36 on: September 23, 2021, 10:33:46 AM »
Here is a experiment I did with a stock OS 46 muffler. I saved 1 oz and runs great.
I removed the back half the the muffler and bolt.
Drilled out the center cone to fit a aluminum tube with a .365 OD to a tight fit.
Insert the tube into the cone 1/8 of an inch and JB Weld it around the inside of the cone
Now JB weld the cone to the front half of the OS muffler and fill the bolt hole in it to.
Grind all the cooling fins off the front half of the muffler.
Al

Offline Al Ferraro

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Re: Best tube muffler for LA-46?
« Reply #37 on: September 23, 2021, 10:43:28 AM »
Al

Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #38 on: September 23, 2021, 01:56:17 PM »
Thanks Al!

What would we do without JB-Weld??

Offline Dan McEntee

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Re: Best tube muffler for LA-46?
« Reply #39 on: September 23, 2021, 04:28:54 PM »
  The modification looks good, but I have never been a fan of the rubber ducky exhaust deflectors. They rob power and add back some of the weight you took off. I have never failed to see a significant increase in RPM on an engine when removed and that illustrates restriction. I'm as lazy as they come but I don't mind wiping down my model!
  Type at you later,
   Dan McEntee
AMA 28784
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AMA 480405 (American Motorcyclist Association)

Offline peabody

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Re: Best tube muffler for LA-46?
« Reply #40 on: September 23, 2021, 06:05:13 PM »
A pretty good NJ engine guy said that opening the muffler exit to 3/8" would not change the 1/4 wave but would let it run coooler.
Works great on the Big Art muffler as well.


Offline Scott Richlen

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Re: Best tube muffler for LA-46?
« Reply #41 on: September 23, 2021, 07:19:21 PM »
I'm thinking of JB-Welding in the aluminum end-tube at an angle instead of straight.  That way I deflect the exhaust and don't need a rubber-ducky.  Think that would work?

Offline Dan McEntee

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Re: Best tube muffler for LA-46?
« Reply #42 on: September 23, 2021, 07:42:47 PM »
I'm thinking of JB-Welding in the aluminum end-tube at an angle instead of straight.  That way I deflect the exhaust and don't need a rubber-ducky.  Think that would work?

     Make it a little bigger and also a little longer and it will help. I found that there would still be oil on the model. If I ever try one again the tube will have a larger diameter than the muffler stinger and maybe even open up more megaphone style. I would like to see little to no RPM changes with or without.
   Type at you later,
    Dan McEntee
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)


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