Tomcat_AL200

I had the muffler on my .61FX fall off the other day (the only thing still attached to the engine were the area around the screws) and I was wondering what to do for a replacement muffler, stock, pitts or something else, and suggestions?

CJ

TopShelf

My Feedback: (4)

CJ,

Kind a depends on your application i.e. what kind of plane the FX is in. If it's in a general sport plane, go stock or maybe an Ultrathrust or Tower. The mufflers for the Tower engines seem to be about the same as the Ultrathrust. The only reason to use a pitts is if you are trying to fit it in a cowl. If it's in a "speed" plane, you would want to look at a tuned pipe.

Mediaman

My Feedback: (1)

I had the same problem. I replaced mine with a Macs Muffler, it's a black pipe looking kind of thing, it's also a one piece item, I believe the price was $39.00, it also gave the engine more power.


Regarding the avatar, MMM Good Taste!!!

DarZeelon

Carlos,


When compared to the stock OS muffler, with the baffle removed, the Macs One-Piece muffler does not give any noticeable power gain, nor does Macs claim it does.

It is significantly lighter, however, but at $36, it actually costs an arm and a leg, without justifiable benefit.

The Tower muffler, if it can fit the OS, would actually give a noticeable power boost and is only $19.

Tomcat_AL200

thanks guys, bump

bob27s

My Feedback: (19)

As noted, your muffler choice depends quite a bit on the applications.

Others have made some very good suggestions.

Let me add the Jett-Stream muffler to the list. By its nature, it is similar to the PSP ultrathrust.


shown here on a SJ-90. Same muffler is available for any 60-90 size engine (and all other sizes too).

Available for the OS61/91FX installation, bolts right on, no adapters, no bolts or pins holding it together, and it will add 600-800 rpm to the top end with no loss of user-friendliness. Plus you get additional muffler/tank pressure, and properly balanced engine backpressure. For scale and aerobatics applications, the turbo-jett mufflers are a great choice for in-cowl installations. Take a look a the jettengineering.com web site.

I hope this is helpful

Bob

TopShelf

My Feedback: (4)

Bob,

Yes, nice addition. I have a Jett 50 which is an awesome engine. Don't know why I didn't have that one on my list. Jett also makes excellent in cowl mufflers. I have one on my OS 91Fx, excellent RPM!

Kent

Tomcat_AL200

bump

Tomcat_AL200

Thanks for all the replys, what I need is a cheap muffler that will work on a trainer, with the same power or more that the stock muffler provided. Also, what would be a good pitts muffler? Thanks again.

Tomcat_AL200

what is a cheap muffler for sport use?

TopShelf

My Feedback: (4)

Either the stock muffler or the Tower Hobbies muffler. For a trainer, I would go with whatever is least expensive. I'm not 100% sure the Tower muffler fits the FX. I know that the 46 muffler fits the 46fx.

DarZeelon

Kento (??),


The two Tower engines are quite dissimilar.

The fact that the .46 muffler does fit the OS.46FX (and a whole bunch of other OS clones), doesn't mean the .60 will too.

From the Tower web site:

The center-to-center distance between the muffler bolts, in the Tower muffler is 41 mm.
In the OS it is 43.8 mm.

The Tower muffler will not fit the OS engine!

TopShelf

My Feedback: (4)

DarZeelon,

Good info, that's exactly why I stated I was not sure. I didn't want Tomcat_AL200 to spend his money on something that does not fit.

Kent (aka Kento, TopShelf)

Tomcat_AL200

thanks for the info guys, I think I'll have to go with the stock muffler, althought the warranty might cover it as it cracked off around the mounting screws in the muffler.

bob27s

My Feedback: (19)

Just for reference......

From our reference list, the OS 61FX has a 42 mm bolt spacing ( I have double checked this - I am not sure why the OS numbers show different)

The ThunderTiger .61 as well as the Magnum .61/.75 have 42 mm bolt spacing as well. They are the same spacing as the OS 61/91FX. Those mufflers may make a viable alternatives.

I hope this is helpful

Bob

DarZeelon

Bob,


The replacement OS .61 FP, LA, FX [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCB98&P=Z]muffler[/link] states 41.8 mm center-to-center.

The [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCA83&P=Z]extension[/link] specifies 43.8 mm and a matching inch figure.

Go figure which is right...

bob27s

My Feedback: (19)

The 61FP and FX use different mufflers if I am not mistaken... Id have to check

I know the OS site shows the 43.8 dimension for the 61FX. Its not what the engine actually measures (on the last 91FX checked at least).

All of the Jett mufflers for the OS 61fx and 91fx engines have 42 mm spacing. They fit perfectly. Go figure.....

Tomcat_AL200

Thank you so much for the information, I think that I'll try the Tower Hobbies muffler. I will fill in the rear mounting hole with JB weld or something like that (would I even have to?) and then drill (should I tap it?) a new hole. The mounting surfaces will mate fine, but do you guys think this would work? Thanks again.

DarZeelon

CJ,


While JB Weld can be used to repair engine castings, I am not completely sure how it would handle the higher temperatures in the exhaust.

You can try, but you can also lose the muffler, it the JB Weld fails.

HavinFun

My Feedback: (4)

I've used JB weld to repair broken pipes on a Slimline pitts muffler for a K&B .61. Heat did'nt bother it although the J&B weld does appear to have a burnt look after several flights, looks the same as the burnt castor. Must have over 100 flights since the repair & still strong.

Tomcat_AL200

The JB would only be to fill a hole, but would I even need to fill it in the first place? thanks

Tomcat_AL200

Do you think if I left the old rear mounting hole on the muffler open that it would cause the muffler to crack, or am I going to have to fill it with JB weld?

Tomcat_AL200

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