Stripped threads in head of Toxic 231

[Gary O]

I purchased a Spectra second hand with a Toxic 231 engine. The heli had not been flown much past break in when I bought it. It has the Hatori pipe on it and the first 2 flights I put on it the pipe vibrated loose both times. On the second time it came loose, it took the threads with it out of the head. After putting a lot of thought into a fix, other than buying a new head, I decided that trying to go back with the same set up was probably going to produce the same results, so I drilled out both holes with a #7 bit and tapped each one for a 1/4-20 bolt. I think the 1/4-20 bolt will hold better since it has a deeper thread pattern and the pitch is more coarse which allows more material to let the bolt bite into. This also involved redrilling the adapter to accept the larger bolt but it went back together perfect. I put it all back with high temp red loctite, which I had also used on the stock bolts, I will be flying it this afternoon to see what the results of this fix are.

[WillJames]

SOunds like it is definitely worth a try. Thanks for sharing your info. We all look forward to your flying report.

[Gary O]

Well, after flying the Spectra yesterday afternoon, my fix still did not work. I'm really at a loss for what else to try on this thing. I had 272 Loctite on those threads and they still backed out. I'm starting to wonder if it has something to do with the adapter. I read in another post about someone trying to machine one out of stainless so it would take out the heat expansion that is such a problem with aluminum. I am willing to try anything at this point. I've got a helicopter that is basically useless as it stands at the moment. :arggg:

[flyinfool]

Can you post some pics?
I am not familiar with the hatori pipe mounting.

[WillJames]

I go pick up the stainless ones tomorrow morning. I hope they are right. Wish me luck!!

[Gary O]

I hope it works out for you. I was watching the demo flight Curtis was doing with John's earlier and it didn't last but a few minutes and he was having to land it with a loose muffler. This is not a reflection on the helicopter in my eyes but the muffler system is a joke.

[WillJames]

Keep in mind, John's machine had made it over 10 flights without the header coming loose before Curtis got his hands on it. ;) The muffler is great at letting these motors produce the best power they can with a muffler, that was John/MA goal. The header is another story. Give us a chance to test with the SS headers.

[bigrcr]

The model had made well over ten flights, nearer to forty in fact since the last time the Hatori had been installed. I had flown the model previously that day and pushed the model HARD, so hard that the blades would pop and complain with the abrupt pitch changes. I was half expecting the model to explode in flight. That probably heated the muffler up enough to loosen it, I have had that happen before.

Of course, you have to take my word for it as Will had his camera in the trailer at the time. :arggg: :hammer

Later,

[WillJames]

Seeya this weekend at the sheep John. Lets put these headers to the test!!

[bigrcr]

Seeya there!

Later,

[WillJames]

So far so good.... :)

[WillJames]

If anyone is interested in a SS Header for their Hatori, please add yourself to the thread below.

http://www.helifreak.com/about6598.html