jsmeed

Bill,
Will the Top Flite header and muffler, originally designed for the O.S. 61, work on the .75AX??

Bax

My Feedback: (11)

Very likely the mounting holes won't line up, though the size of the muffler should be OK. After all, it will work with the SuperTigre G-75.

bigtim

My Feedback: (13)

does this mean the muffler mounts are not the same for the 75 as the 61 and 91.
the header will fit both of these engines correct?
another question origonally intended for the 61to91 engines there was a issue with over heating the 91 is it the rubber connector that was the problem or just the size of the whole set up, the reason I am asking is I have a 91 and a club member uses one of the headers for his,but runs his engine rich to keep it cooler and hasn't had any problems.
if its just the connector then I could fabricate a metal replacement as a bridge between the 2 parts instead of the rubber part, what's is the real deal the TF header looks about the same size as a pits style muffler except for the rubber section.

sevans16

I bought the slimline pitts style muffler and the package had the 61FX listed. Also the Powerbox weighed right at 6oz and the slimline weighed in at 2.6oz

bigtim

My Feedback: (13)

the mounting holes line up for both the engines the 61 and 91, the nice thing about the TF header is the engine can be tilted slightly so the carb doesn't drip fuel it also fits in the crook under the engine box in the cowl neatly.
there is not much comparison info on the 75AX if it would mount up to the TF header it would work pretty good on there planes for the power having to modify the actual header doesn't seem do able there is already pre drilled and tapped holes there is alot of room to weaken the header,its really not very robust.

oldtyme

bigtim,

I had these same questions because I was going to use a ST75 in my TFP47 but when I saw the OS75AX I bought one and one of the headers made for the OS61FX. It fits the 75AX perfectly so I'm going to use the OS75AX instead.

Cheers,
Andy

bigtim

My Feedback: (13)

thanks Andy,A question for ya how much does your Jug weigh the 75 looks like a powerfull engine and I like the idea of not having to cut the cowl to get it to fit in there.
mine that I am building is looking like about 10lbs glassed and painted.

oldtyme

bigtim,

It's a work in progress so I don't know how it'll come out. The thing I do know is that the OS is a lot lighter and it is rated at .2 horspower more than the ST. The ST is rated at 2.2HP and the OS is 2.4HP.
I'm going to guess that my jug will weigh in somewhere between 10-12lbs with the retracts and tanks.
I also am going to glass mine.

Andy

Bax

My Feedback: (11)

It's the entire flow-through of the muffler. It just doesn't allow for the volume of exhaust gases of the .91. Also, the header is a bit abrupt where the exhaust exits the engine...the turn is too tight for the .91. .75 and smaller aren't so affected.

Mounting is not the same for the different engines.

Please note that this is not a discussion forum, and posts by other than a Top Flite rep or the original poster will be deleted, per RCU rules. People who ask relevant questions in the same thread are allowed to post, but only a proper rep can answer.

EDIT: We were able to get an O.S. Max .75AX to check, and found that it does have the same muffler-mounting dimensions as the .61FX, so the Top Flite Header for the O.S. .61FX will work.

CustomPC

I have been told by someone with a .75AX that the exhaust bolt mounting holes are the same as the .61FX. Any header or muffler designed for the .61 should bolt right on to the .75AX. The other issue of whether said headers/pipes have enough volume or flow for the larger .75 can only be determined by testing i gues,

bigtim

My Feedback: (13)

it's funny that the answer was given by a non rep and deleted
so why hasn't this been checked by the rep I wouldent mind buying the 75AXif it works with the TF muffler,instead of scolding the poster and deleting his post, how about checking the products and giving a solid answer either yes or no instead of some sort of guess,from the deleted posters answer it sounds like the TF muffler fits but verification from the rep would be in order I have 2 built TF kits and 3 unbuilt kits.
from the specs it sounds like this engine will provide plenty of power, if a in cowl muffler works with this engine, then all the better, I wouldnt spend my $ on a engine that has a muffler hanging out of the cowl for my warbirds.

GII

My Feedback: (14)

can some one tell me Will the Top Flite Exhaust Header O.S. 61SF/61FX , work on the SuperTigre G-75 so I can use the Top Flite In Cowl Muffler for .61-.75 for my P-51D Mustang