Funflyer
06-12-2008, 10:13 AM
I finally finished my 5003D last Sunday just as it was getting dark. :roll: I haven't had a chance for a maiden until today. I got to the field, flew the Rex450 for some practice and to calm my nerves (hey, the Logo is twice the cost of the 450...). I knew things should be ok because I had checked and re-checked everything during and after the build. I did a pre-flight check last night and one today before plugging in the battery. I range checked, tested failsafe and everything was a go. I started spooling up and my first clue was that the tail rotor spun up very fast. It was really humming along and the main blades weren't a spinning death disc like I had anticipated. Hmmm, mid stick and no lift what so ever. :thinking I pushed the stick full positive and it didn't budge. I quickly shut it down and went to investigate.
The tail was clearly working, I thought maybe I installed the one-way bearing backwards or something but no the main shaft was locking up and turning like it should. Wait a second...I'm holding the main grips and the main shaft is turning. :shock: I thought I sheared off the Jesus bolt, but it was in one piece. Uh oh, that only means that the Jesus bolt isn't through the main shaft, it's riding on TOP of the main shaft. Holy crap! :wow2:
Thankfully I've got more luck than common sense. :oops: If the head had been spinning fast enough for the full positive pitch I gave it to pull the head block off the shaft then I would have had one nasty pretzel or worse! :badair:
I was so careful during the build and made sure everything was working correctly. I even spun it up on the desk with only paddles to make sure the motor and gear mesh were working. AND, when I test spun the head over and over again to make sure the belt wasn't too tight, I couldn't feel the shaft slipping, I don't think it was. So the root cause is that my head block fits VERY tight on the main shaft. I distinctly remember having to force it on and it bottomed out solid. Then when I looked through the Jesus bolt hole I saw daylight and thought I had gotten really lucky to line it up on the first shot. I didn't try to move it because I know how hard it can be to get the two holes lined up. :arggg: Actually the head block bottomed out so hard the first time I set up the head that it actually made the shaft locking collar move about 5mm. So at the field I pulled off the head block and tried again to force it all the way down. It kept bottoming out and I couldn't force it any further. When I took it all apart there was a small lip and some melted plastic in the way. I had to scrape it out and smooth off the lip with the end of my allen tool before I finally (with a lot of force) got the head to go down any further. Of course the swash and pitch was then way off so I had to abort the maiden attempt because the sun just dropped below the horizon...
I'm such a lucky idiot! :Slap:arggg::badair::badair::badair:
The tail was clearly working, I thought maybe I installed the one-way bearing backwards or something but no the main shaft was locking up and turning like it should. Wait a second...I'm holding the main grips and the main shaft is turning. :shock: I thought I sheared off the Jesus bolt, but it was in one piece. Uh oh, that only means that the Jesus bolt isn't through the main shaft, it's riding on TOP of the main shaft. Holy crap! :wow2:
Thankfully I've got more luck than common sense. :oops: If the head had been spinning fast enough for the full positive pitch I gave it to pull the head block off the shaft then I would have had one nasty pretzel or worse! :badair:
I was so careful during the build and made sure everything was working correctly. I even spun it up on the desk with only paddles to make sure the motor and gear mesh were working. AND, when I test spun the head over and over again to make sure the belt wasn't too tight, I couldn't feel the shaft slipping, I don't think it was. So the root cause is that my head block fits VERY tight on the main shaft. I distinctly remember having to force it on and it bottomed out solid. Then when I looked through the Jesus bolt hole I saw daylight and thought I had gotten really lucky to line it up on the first shot. I didn't try to move it because I know how hard it can be to get the two holes lined up. :arggg: Actually the head block bottomed out so hard the first time I set up the head that it actually made the shaft locking collar move about 5mm. So at the field I pulled off the head block and tried again to force it all the way down. It kept bottoming out and I couldn't force it any further. When I took it all apart there was a small lip and some melted plastic in the way. I had to scrape it out and smooth off the lip with the end of my allen tool before I finally (with a lot of force) got the head to go down any further. Of course the swash and pitch was then way off so I had to abort the maiden attempt because the sun just dropped below the horizon...
I'm such a lucky idiot! :Slap:arggg::badair::badair::badair: