jbeech
rrAdvertiser
Location: Sanford, FL (Orlando area)
| You knjow what the right thing to do it! Pull it and roll it. Checking shafts is always done most easily by rolling it on a mirror, or piece of glass, to verify it's true. If it's bent you'll easliy see it wobble, or listen for the telltale tick, tick, tick indicating it's bent as it rolls across the glass.
There are but three critical shafts on a Tiger 50, the most delicate is the feathering spindle, or spindle shaft, which connects the blade grips. This 5mm diameter shaft is both inexpensive to replace and the job is easy to do. Not checking one after a hardish arrival (which both broke skid legs and bent the tailboom) recently cost me a bad crash later. It's because I was stupid and got in a hurry - again (I had neglected to thighten the tailboom in the first place which is what originally caused me to have the emergency leading to the hardish arrival in the first place). Anyway, I both broke my heli in front of folks (which was embarrassing) and it also forced me to re-learn the lesson about being lazy and not checking shafts (the very point of this little discourse since occasionally we all know the right thing to do but feel lazy and want to take the short cut).
The other two shafts of note are the tail output shaft (also 5mm in diameter) and of course, the main shaft (a hollow 10mm diameter shaft - did you know a hollow shaft is not only lighter and more expensive to make but it's real purpose is it's harder to bend than a solid one?). Anyway, servicing the tail output shaft is also easy. By just pulling three 3mm bolts holding the sideplate to the tailcase proper the tail output shaft is immediately accessible and turns out to also be duck soup to service.
The mainshaft is a little more difficult to service, but not by much. First undo the bolt at the bottom of the shaft (the one holding the autorotation clutch in place). Next, lift the whole assembly (mainshaft, swashplate, washout, head) off the helicopter - but not all the way out. Once it's loose, I slip the bolt holding the autorotation clutch back in place temporarily. The only reason for the extra step here is to keep from maring the shaft with a set of Vicegrips. I.e I'm using the head assembly (wrapped in a shop rag) as the handle to first loosen the shaft from the autorotation unit followed by loosening the head from the shaft. Since the swashplate and washout are a loose fit on the shaft and aren't an issue.
Anyweay, next I remove the Jesus bolt (the one holding the head to the mainshaft) and I pull the head assembly loose. Then, I loosen the setscrews on the shaft collar (between the swashplate and the upper bearing) and remove it (unless the shaft is really bent in which case it's harder to pound/pry off), and finally, I re-remove the bolt holding the autorotation clutch in place and finish removing the shaft.
If I know for sure I bent the shaft, I jump straight to pulling the head and then I grab the shaft with a Vicegrip and using a hammer to tap the side of the Vicegrips I pull things loose.
By the way, I may film the procedure and post it on the website. But folks, before I divert my efforts to this, is there any interest in seeing this done, or is it clear enough from the description? |
