I guess I must have crooked eyes because everytime I install a turbine in an airframe, I have a heck of a time eyeballing the thrust line. So after trying to use straight edges held up to the outside of the turbine (with no luck) I came up with this little device. What do you think?

The black cone I had laying around and I believe it was some sort of protective cap over a large insulator for power generation lines. But it could easily be made from thin fiberglass over a mold or even rolled out of stiff cardboard. I trimmed it so that it would be a tight fit onto the inner tailcone of my P120. I made sure that it didn't contact the EGT sensor. I slide it over the inner cone until it comes up snug against the inside of the outer cone.

Then I cut out 2 centering discs. The smaller one is balsa and is 2" diameter. The larger is liteply and is 2 5/8" diameter. Both are drilled for the size of the arrow shaft. I glued the smaller disc onto the one end of the shaft. I slide the small disc and shaft into the black cone until it is snug and then slide the larger disc down the shaft until it centers in the end of the cone.

The first pic shows my alignment tool. The second pic shows a misaligned turbine (exaggerated). Pic 3 shows the alignment tool installed in the misaligned turbine. Pic 4 shows the turbine and alignment tool after I have straightened it.

I also tried this tool on my EuroSport by inserting the tool into the turbine and then sliding the tailpipe into position. What appeared as a perfect alignment to my eyes, showed to be slightly off with the alignment tool.

Gary, first of all, good thinking, this has always been a problem for me. I was aligning a tailpipe with Todd a few months ago and while I thought it was straight, and he glued the mounts in place, after he looked up the pipe, he undid the glue moved the mounts and set it again. I was embarrased and a little put out. Are my eyes that much off? Or is it simply that everyone's view of this will be different?

Two questions though:

1) How do you know for sure that the black insert into the tailcone is in perfectly straight? Are you using a couple of levels or something?

2) If the question to #1 is licked, how can I get you to make me one of these?

Sean

Hey, First off, I'm no engineer.

But I'm guessing that since I have a tight fit on the inner cone and then as I slide it in a little farther I get a tight fit on the inside of the outer cone, that I am real close (close enough) to being centered. Now if the outer tailcone and inner cone are not on the same centerline, then I am going to be off with my alignment tool. But I would suspect that these 2 are on the same centerline, so I think I'm there.

Any experts want to chime in? Because it's possible I'm all wet in my thinking. But I know both turbines I tried the tool on, looked to be in better alignment once I adjusted them.

gary

looks like a good way to get there. i would want some lines on my black cone so I could make sure it was installed straight. a little off there and the projected thrust would look way off.

What about finding the centerline on your a/c and with a marker draw a line down the middle. use the gig you made and it should come out perfect... I never would have thought of a gig like that.. my hats off to ya..

Patf
There isn't any way to adjust the way the cone installs. It is a tight fit over the inner tailcone and then I have to push it until I have a tight fit against the inside of the outer tailcone.
It seems to me that it would be self-centering with no way to be off center. That is assuming that the inner and outer tailcones are on the centerline and that the inner tailcone is not deformed.

Here are a few more pics to show how the cone fits:

Pretty cool tool Gary. You submit it for a patent.

JR Gautreaux