skyraider71

I need a muffler for this engine. The strap-on stack is made by
DuBro. I would like to use muffler pressure.
I got this Senior falcon at the swap meet last fall and I would like to
fly it with this engine.

All Day Dan

My Feedback: (5)

Try here. Dan.
http://www.bissonmufflers.com/en/index.html

big max 1935

My Feedback: (9)

Stock muffler for this engine is a OS-704. Mounting strap is a 26425707. You might find them on one of the for sale sites. Good luck, Max H. AMA 14958

W.E. Fan

There is currently an OS 704 up for sale on e**y. Seller seems a bit optimistic with his buy-it-now price for 50 even, but who knows?Maybe this muffler is rare and worth every penny.

Doug

Michaelj2k

Yup. When they show up, they don't go cheap. I bought one there; paid at least $45 for it.

countilaw

The O.S. 744 A muffler fits the Gold Head 60. It's a bolt throughthe muffler type. There is another 744 muffler but it's the "B" (744B) that fits the O.S. .61 SF which is a bolt through the engine case muffler.

The 744A also fits the .61 FSR. The O.S. Max .61 FSR on has the letters SR on the right side of the engine in a circle.

The 744A is a common muffler and usually easy to find. It's a better muffler than one that uses a strap around the cylinder.

Frank

skyraider71

O.K. good info here. Thanks guys.
BTW, my engine says Max-H on the side of the case, can anyone
tell me about when it was made?

countilaw

The - H signafies that it was originally a Helicopter engine. It will have a lightened piston and connecting rod and a modified crank shaft. It's a possibility that the gold head was used to replace the original heat sink head.

An original gold head (late 70's) will just have O.S.Max on one side of the engine and .61 on the other. One the left engine mount lug it will have "Special Edition" molded in (not stamped).

Frank

big max 1935

My Feedback: (9)

The OS "H" series of engines came out in the late 60's with a silver (aluminum) head & air bleed carb. Also was a silver head .80 rear rotor that had "H" on the side(used a longer strap) . Gold head "H" was next with a airbleed carb in both the front rotor & rear rotor versions. Then they went to a two needle carb that is the one you have(mid -70's) . Next was the "H" Blackhead .60 & two needle carb . That was the end of the loop scavenged engines .All used the 704 strap on muffler ,NO bolt on .OS also made a extention with a longer strap (REAL scarce). Several other after market mufflers were made for them so you might ck for them also. I had good luck with a Kavan . Max H.

W.E. Fan

Skyraider 71,

If we were to use the advertising of theAmerican distributor at the time (World Engines), it seems like the Gold Head was introduced early in 1971. In late 1974 World Engines adsthen showed the Black Head as the successor to theGold Head. So...your engine is most likely40+ years old.

Doug

UStik

Must be between Gold Head [link=http://www.osengines.com/history/ostimeline04.html]1968[/link] and Black Head [link=http://www.osengines.com/history/ostimeline05.html]1974[/link], same year as the Schnuerle-scavenged 60F-SR. For reasoning behind parallel offering of loop-scavenged and Schnuerle scavenged engines see two reviews each [link=http://sceptreflight.net/Model%20Engine%20Tests/Index.html]here[/link] (top four links in the rightmost/third column). Muffler info included as well. What Big Max said...

roncoleman

My Feedback: (14)

Here's one for you but you will have to check with the guy about postage.

http://www.ebay.co.uk/itm/OS-704-MOD...item19ddf2ff54

JohnBuckner

My Feedback: (1)

I don,t understand, you already have the Dubro tongue muffler and if a pressure tap is all you want just drill and tap the dubro for a pressure tap. Some of those tongue types also came with a pressure tap.

John