Engine reversal

[Raisintoe]

A few weeks ago, I took my TT Titan X50B out to do 3-D flying for the first time ever; I mean, even the first time I've ever done it. I programmed my own radio and everything. I tested out my settings just hovering; then took it way up high. I turned to my brother and said, "should I do it"? Before he could respond, I did it . . . It was awesome! I did a perfect back-roll, then again, and I hovered it inverted for a few seconds! I was so exited. I flew it for a good while, then when I was getting close to landing it, I did a really fast fly by, (normal fly by), and my engine bogged down; way down . . . Then it almost quit, and immediately went full throttle without any tourch to the blades. I was too late to land an auto-gyro, I had already bogged down the blades too far, So we watched my new heli go into the grownd.

I figured afterward that the engine had to have reversed. My first thought was that the clutch broke, but the clutch is just fine, and so are all the other connections between the blades and the engine. So when the engine just about quit, it would have changed direction.

Now, I need to do something different with my engine throttle, I suppose, so that I don't bog it down in forward flight! It was my mistake to never set a throttle-swash mix in my controller, I guess I need to do that. The engine would always bog down when I would fly kind of fast.

Anyway, I was hoping I could get some expert advice here. Is that the only thing I would have to change? (I mean the throttle-swash control mix), or are there perhaps some other things I should look into so this doesn't happen again?

[Elgyn]

can't go backwards the way you're describing. There's a one way clutch not to mention the motor can't run backwards effectively to produce any power to almost stop the blades. Sounds like other mechanical issues

[johnbs8]

i would say start by getting it tuned better. i was breaking in my ys56 and the needles were way fat. it would dog out on climb outs. anyways i started it normally, pumped the throttle and all was good. then went to spool up and the engine reversed. i shut it down and restarted of course. if your bogging on just fast foward flight the you have tuning issues i would imagine.

[Raisintoe]

On climbs, the engine seems to do just fine. I suppose that the engine does run a little rich as of now though. I will have to tune it up better as you said, I'm sure that will make a difference.

[johnbs8]

I flew it for a good while, then when I was getting close to landing it, I did a really fast fly by, (normal fly by), and my engine bogged down; way down . . . Then it almost quit, and immediately went full throttle without any tourch to the blades. I was too late to land an auto-gyro, I had already bogged down the blades too far, So we watched my new heli go into the grownd.

now that i reread your original post, did you run out of fuel?

[Raisintoe]

No, I definitely did not run out of fuel, The engine went full throttle, and was not turning the propellers. Later I ran the engine, and I found that the clutch still worked as good as new, so the only conclusion that there could be is that the engine reversed.

[DethWshBkr]

ON starting my Thunder Tiger Pro 46 yesterday on my airplane - it started, but backwards. I slipped off the prop with the starter, and the back motion actually caused it to start, reversed. It would NOT take ANY throttle, and barely idled. I was curious to see what it would do, and it would barely run. I highly doubt the engine went backwards on an increase to full throttle...

I did have my X50, YS56 engine, spool up on me to max throttle on a punchout at about 50 feet, and not spin the blades. I thought it just leaned out and quit due to running out of fuel (I do auto practice until out of fuel on the header tank), but when I landed it, the engine was still running. That night, it worked fine.
I'm thinking a one way bearing sticking somehow...

[carlos]

sounds like you have over pitched it. causing it to "Bog" something must have let go cause rotary valve induction glow engines will not run at full throttle in reverse.
What cooling fan do you have fitted.

[darryl123]

are the 4 bolts still on the maingear?

[Raisintoe]

Originally Posted by carlos

What cooling fan do you have fitted.

I have the plastic one that came with the X50B kit. In fact, I am using all the original parts from the kit; no upgrades.

[carlos]

not much chance of that slipping then.

Hmmm ! Clutch liner maybe.

[Raisintoe]

Clutch liner looks fine from what I can see. The change in throttle was immediate; from nearly off to high throttle.

I just got the replacement parts to fix my heli, I will give it a go soon and see how it does.

Thank you for the help, Your experience helps a lot. I will let you know how the test flight goes.

[carlos]

It might look fine but you need to see/feal if it has come loose

[Raisintoe]

I flew My Helicopter on Monday, and it worked great! On my third flight though, my engine quit while I was maneuvering out of an inverted hover. But this Time I was ready for a miss-hap. I flipped my switches for emergency landing, and made a perfect auto-gyro landing My very first one at that! (Although, I have practiced a bit on the simulator.)

I figure that the engine only quit though because my muffler had come loose, and there was no backpresure feading into the fuel tank.

I probabley also need to invest in a governor. There are so many different stresses, (I am realizing), that can cause change in the RPM. It is not bad without one, but I suppose that I waill need one if I want to do more 3D flying.

[Taxus812]

The situation you described in the original post is: The one way bearing slipped\let go.

Once it breaks loose it wont re-engage until the motor\head is stopped. With no resistance from the blades the engine RPM will jump WAY up (and loose head speed). When you shut the engine off and start it again it grabs like it did before.

I know this because it happened to me several times. It may or may not let go again. Mine let once on my Raptor 30. It also happened on my Hawk III.

Terry

[WessCo]

Hope you didn't mess your engine up with a loose muffler.

[Raisintoe]

Gee, this is an old post now, but I have to update on what I have found, as this doesn't seem to be a common issue.

About a month ago, I took my heli out again, and when I tried starting it up, the engine would only run backwards! I could punch the throttle and it would run full speed going backwards! I am convinced that my engine reversed while in flight. That also explains why the clutch would not grab while I was flying, the clutch actually had drag from my motor, that's why it fell out of the sky so fast.

My engine runs fine now, I found that one of the head-bolts was loose.