Tuned Pipes for the Spectra?

[Gary O]

I have 3 Spectra G's in my fleet of 18 MA helicopters and they are all going to be shelved until some kind of fix is found for this Hatori pipe coming loose. I tried another band aid yesterday and it came loose in less than 5 minutes just hovering. Whoever came up with the idea of taking a chunk of aluminum and hiding the bolts where you can't get to them to check them had their head stuck in the sand or something. The SS header was the way to go but I understand those are not available anymore.

Just about any other type of material would be better than aluminum. It expands with very little heat and that big a piece just won't work. A header attached to a tuned pipe by way of a coupler to keep the vibration down would also work. This is a great helicopter, but the pipe situation sux.

[carey shurley]

Hey Gary

Hatori has a new muffler, the SAB-12R, its made differently in that it has a small s/s plate that bolts to the engine and then the muffler mounts to that. I have not tested it yet, however I expect to in the next two weeks.

Unfortunately, this can't be retrofitted, the mounting on the muffler itself is very different.

Tim has many of these in stock now.

What was the bandaid you tried?

[Gary O]

First I tried a mounting plate supporting the rear of the pipe thinking maybe the vibration was the major cause. That failed to make any difference other than that the pipe didn't fall off. The next thing I tried was tapping the hole in the Hatori header for a 10mm set screw to tighten up against the original bolts that hold the header in the head of the engine, plus the set screws that are in the Hatori muffler originally. I thought the set screws internally would do the trick since they couldn't back out because I made them flush with no where to go. They didn't back out, but what's happening is, the header, being made out of a chunk of aluminum expands at such a rate that when it grows, it loosens up on the engine. The only thing that is going to solve this issue is not letting the heat get to an aluminum part. Aluminum will not work in the way Hatori was shooting for here.

[bigrcr]

Gary O,

Through many, many trials and tribulations, that is exactly what I have tested and proven. The Stainless adapter IS the solution. The aluminum expansion rate is the culprit. No matter how bad the motor vibrates using the SS adapter the adapter does not loosen, ever.

I knew that the aluminum adapter would not work from the moment that I saw it. Years ago we had the exact issues with the el-cheapo Bennet style mufflers on G-62's, 38's, Q-40's, Q-42's and 23's. Going to a steel or stainless muffler or mount solved the problem. At least we have been lucky, on the airplane motors that I have referenced we would usually have to go back in and repair or replace the blocks as the bolt holes would strip out of them.


Later,

[Toadster25]

Has anyone tried the new muffler yet. How much is it?