OK, I'll admit to my most stupidest thing I've done in my heli flying. Hopefully others will not repeat what I did.

Last week I was flying my Raptor 50(OS 50SXH, 600mm SAB glass blades) in the late afternoon. I finished the flight and was hovering (hover-taxi) back towards the pits. I usually stop about 150 feet away or so. I noticed that I was almost out of fuel (30% cool power) and decided to just run it out of fuel and do a hovering auto. Now I've done this many many times before so I expected the engine to rev up a little and then quit as it runs out of fuel. Saves me from draining the tank.

Well, this time the engine did not react the same way. It leaned out alright, but didn't quit. It kept getting leaner and the head speed went thru the roof!
As I was thinking " wow, the head speed is way too high, I'd better shut it down" by the time I finished that thought, Yep, the heli went "BANG" and the blades flew off, (as did the flybar and misc other pieces)
I stood there stunned (I knew the high head speed was not good for the mechanics, but I didn't think it would throw the blades) and thought "OH GOD, THANK YOU FOR NOT LETTING THE BLADES HIT ME"
I don't know what RPM is considered redline for this heli, but I would guess that it was spinning somewhere between 2500 and 3000 rpm. If the blades hit me standing only 15 feet away, I would be in a hospital or WORST!
I've heard on occasions where helis would throw a blade during some wild manuevering but this is the first time I've witnessed it. The whole thing happened in just a few seconds and luckily there was only one other person at the field. (he jumped as one of the blades was headed his way, but the blade lost the energy and stopped about 30 feet from him)
Another reason not to fly alone! Sometimes things happen before you know it.

LESSON LEARNED: NEVER OVERSPEED THE ROTOR. IF YOU HEAR THE REVS GOING TOO HIGH, IMMEDIATELY TAKE ACTION AND LOWER THE THROTTLE OR HIT THE THROTTLE HOLD SWITCH.

It only took a few seconds, but I could've been seriously injured or killed.

Yikes!

It is not stupid to do that. This type of thing usually doesn't happen. It speeds up for 2-3 seconds and quits. If it doesn't you have a problem.

Just a thought. If you have your engine set pretty close to a good setting, then you probably wouldn't be that far from the optimal setting. If it goes too lean it looses power or quits. So if you are hovering at 1500 rpms or even 1700 then engine probably won't increase more then 300 rpms at the most. Thats 2000 rpms max. Thats a lot of stress but the head should be able to take that abuse a lot longer then that.

That would have scared the crap out of me!!! I'am glad no one was hurt!

I know how you feel,the other day i was hovering my fully upgraded hirobo shuttle{side on hovering,now that i can do it}when all of a sudden i heard a bang and saw the that one of the tail blade grips had come off in flight! the heli started to shake badly so i paniced and dropped the pitch and the heli dumped itself into the ground and the tail blades hit the ground!it cost me £26 to repair the damage to the tail! turns out that the screw had failed in flight,it sheared in half under the strain of the tail blades rotating.after consultation with the local model shop,it was decided that the reason for the failure was that the tail blades had been bumped on several occasions during transit,causing a weakness in the screw that led to it's failure,so be warned,if you have ridged carbon tail blades take care not to bump them as it can fracture the small{very small!}screw that holds them!

Airbike, I'm curious as to what failed. Did the blade bolt shear? Did the blades holder separate from the spindle or did the blade holder fail where the blade bolt goes through? Maybe even another way? This is assuming there is enough left to tell what failed first.
I know I have done the same thing on a regular basis, the drained tank auto that is. Mine has never leaned out anywhere near that much.
Later,,,basmntdweller

Basmndweller, one of the blade holders separated at the spindle where the bearings are located. The blade bolts were not sheared off. I suppose the metal heads with metal blade holders are quite a bit stronger. But then again, I'll try to never over-rev the head again so I don't need to find out for sure[&:]
I think I'll hover the heli a bit farther away from me too from now on

Did the bearings pull out of the blade holder or did the spindle fail letting the bearings stay in the blade holder?
Thanks again,,,basmntdweller

The spindle was bent but intact and all the bearing were still on the spindle. The plastic blade holder broke apart at the bearing location. I guess when you look at the amount of plastic holding on to the bearings, it isn't very much. But then again it wasn't designed for that much of an over-rev.
Fly safe. We also hear of tail blades letting go from time to time.

Why would you purposly run it out of fuel in the air???

No fuel-- No oil....

Second.. If your mix was set correctly, it should only over-speed a little-- a couple hundred RPMs.

If your mix is so rich that you gotta have 3/4 throttle or more to keep your head speed up at hover, then it would over rev much more when you run it dry.

Set-up your throttle hold switch and use IT for auto's and emergencies like this.

Only run it dry at idle and at the end of the day.

Your engine will thank you!!

Kirk

Um.........no comment.

you run it out of fuel so you don't have to do it on the ground. I think it is smart to do but should have hit the hold. Glad no one was hurt.

on transmitters that have an LCD screen, will it tell you what RPM it is at? And can you program it not to let it go over a certain RPM?

Nope, Eco8_kid' transmitters don't tell you anything about the helicopter; they only send the signal. the LCD screen can tell you trims, times, transmitter voltage, and REALLY helps set-up, but there is no information being sent back to the transmitter. There are devices to limit rotor speed, but they aren't always neccessary unless you do 3D or have a real need for this device, called a governer.

I know what throwing a blade sounds like, I've seen it happen and it sounds like a bomb going off!

Colin