A different kind of tail failure.

[marked23]

I was packing it in today when that guy finally showed up. He asked if I would go up and do one more flight.

I agreed.

Pretty much all the same stuff I always do, then at 150ft… Fling! zip…zip…zip..zip.zipzipzipzipzip. The heli was pirouetting like mad. Totally faster than other tail failures I’ve seen. I tried to do a piro flip to bring it right-side up, but it was just going too fast. And you could tell it was about to tear itself apart. So I hit throttle hold and watched it fall. About 20 feet from the ground, it leveled out inverted, I fed in some negative pitch and spent whatever blade energy I had bringing it into a low inverted hover. (While it sounds like I knew what I was doing, I think I was just lucky to find it relatively level just before it hit the ground.) It was on the other side of the tall grass, so I couldn’t judge the height, so I just landed it, inverted, on the horizon that I could see. I’m guessing the blades stopped flying 5 or 10ft off the ground.

My tail flew off. The whole tail assembly slipped right off the end of the boom. It dragged the tail control rod with it. Yanking the ball ends right through the guides. After that, the torque tube shot out like an arrow. When the heli started to piro really fast, the boom broke. The Fury tail is clamped, glued, and anchor screwed to the boom. Let me say that two out of three isn’t good enough. Either I forgot to tighten that anchor screw or it backed out. Either way, it wasn’t where it should have been.

I’m going to have to replace that boom, and a few rods, but it looks like everything else was undamaged. Right after that, the guy who came to check out the helis said, “Hey, you want to fly my heli now?” It was a stupid question. Along with my T-Rex earlier, I had already crashed two helis today, so I replied with a stupid answer: “Sure!”

-Mark

[capebob]

I watched it happen to an Ion a few weeks ago except this time the whole boom departed. Spectacular!

Bob

[WillJames]

I have seen it happen to a few Extremes, once that tail drive come out of the delrin coupler, you are in for a quick spin, no doubt.

I rough up the end of the boom, and inside the boom brackets with some pretty mean (I think 150 or 200 grit) sandpaper then clean very well with denatured alcohol, then use plenty of the black CA on it. Worked good so far....

What method do you use Bob?

[Raptor30Heli]

I agree with William.

I had my tail rotate 30deg off vertical during a flight once. From that point on, I ALWAYS roughen up the boom and CA the plastic tail trans mount on.

No problems since.

-Mike

[DavidH]

With the open style tail box. Really no way the box is going to depart the boom. The open style tail box, the bolts holding it on go thru the boom clamp and then thru the boom and attach to the gear box.
I have used the open style gear box clamp with the closed style gear box. It works well. Pictures are in my gallery.

David

[Gary O]

I havent had any problems with any of the open tail boxes except on the Spectra when they first came out. I still rough up the ends but I haven't done what Will is talking about with the CA thing though.

[Yellowjacket]

This is kind of a funny story :D

I was flying at the Vegas fun fly a couple of years ago and with one of my fury ex. and I threw a tail grip off, the version two tail hub came apart.
It did the same thing…the tail went into a ferocious shake and we could see it throw the tail box off and it spit out the torque tube and of course I was inverted :shock:

I was moving pretty fast from left to right I didn’t know what happened at the time all I could see is the tail went into shake and parts were fling off meanwhile the heli was spinning like a top!

Back then I was leaarning a lot of inverted pirouetting maneuvers like circles and other things. (So what I’m saying is up to that time I had some experience controlling the ship pirouetting inverted) I tried not to get to shook up and keep my cool and try to minimize the damage :?:

I knew I had one shot and I had better make the best of it. I hit throttle hold and was able to stop the speed from left to right. If you guys have ever been to Vegas they have an asphalt runway and sage brush beyond that. I managed to keep it flat and flared just before it hit.

I set the radio down and set out to find my ship. When you get out there you get a little disoriented and people from the flight line were pointing in the direction where it went down. When I got close I could hear it idling (I forgot to kill it) I found the ship lying on its side.

I couldn’t believe it there was no damage the fly bar was slightly bent a blade tip and the wind shield had some minor scratches.
I dug the dirt clods out of the head and brought the ship back and no one else could believe it either. I got a standing ovation :D

A few people including Alan szabo senior helped me find the rest of the parts we even found the tail grip, a guy said he almost stepped on it!

Earlier that year I got popular for a curtis maneuver where I would take off with a forward flip (just enough to clear the blades) and take off backwards inverted a couple of hundred feet with the tail about a foot off the ground as fast as it would hold the tail :twisted:

Well one day I stuffed the tail in the ground as I did the flip and broke the end of the boom off :arggg:

It was about 25 feet from me pirouetting inverted like a top. I hit throttle hold and held it in a hover until it slowed down and started running out of blade speed. I did a quick jerk on the collective just before it hit trying to kill what blade speed I had left.

I got out of it again with no additional damage. I know a lot of both situations where dumb luck!!
I had flown those blades for a little over a year and all the crazy things I did plus those two inverted autos where it landed on the head… I thought these deserved to go on the wall in my shop.

Another thing Id likes to throw out here. If your flying the older open tail boxes (the one with the roll pin thru the tail shaft) BEWARE!! The tail shaft will break in half where the pin goes thru.I had this happen last week; it threw the hub, grips and blades. I was able to get it down again
But was not happy to see this :arggg:

After this I seen a buddies open tail box and it had a black ring around the out put gear with dog point set screws. I did some research and from what I understand there is a new tail shaft with dimples instead of a hole drilled in it I’m going to get the new out put gears and shafts.
Bill

[marked23]

David,

If I use the new clamp, do I have to mount it ont he other side of the boom, like your picture shows?

You said "bolts", but in your picture I only see the one. Is there supposed to be a through bolt on both sides?

How do I find the part number?

-Mark

[marked23]

I think I found the part number: 123-86 Is that right?

What's that 123-88 part for? Do I need one of those too? I am going to try the new clamp with the closed gearbox.

-Mark

[DavidH]

Yes there is suppose to be bolts on both sides. But I didn't want to drill and tap new 3mm holes in the gear case. So I only used bolt on one side. It is not going anywhere with just one bolt thru the boom and holding it on.

The part number will the same as the clamp for the open gear box.

David

[capebob]

What method do you use Bob?

I fly more sedately than most befitting my age, so all I do is rough up the boom and clamp it in in real tight. Then I put a line of liquid paper on the boom where it enters the boom clamp so I can tell if it's creeping out.

Bob

[WillJames]

Another thing Id likes to throw out here. If your flying the older open tail boxes (the one with the roll pin thru the tail shaft) BEWARE!! The tail shaft will break in half where the pin goes thru.I had this happen last week; it threw the hub, grips and blades. I was able to get it down again
But was not happy to see this


I have 85+ flights on my Roll Pin open box, no problems yet. I know a few people still flying them. I will upgrade just to keep the parts current with production, but I have never had trouble with any of the open boxes, including on my Spectra G.

[Yellowjacket]

I called Tim today
he said to send in all my old open tail boxes and he would warranty them and was very nice about it.

He also said he is using a different co. he gets his tail-shafts from because
he said they were not hardening them right.

He said on all the new shaft's ther are no holes drilled thru them anymore.
Any way thats the word for now.

Bill

[Gary O]

I was looking in one of my cabinets last night and noticed I have 2 of the original open tail boxes. The ones that first came out. I need to get with MA and get those updated with the new parts.

[Rada70]

how can you tell the difference between the old and new open gear box? IS it just the shaft? thanks

[ddavison]

Output shaft and output gear. The shaft has two dimples into which the set screws in the new output gear seat into.
Threw a tail rotor myself last year due to my own error. Installed the new clamping system with a closed gearbox, forgot to drill the boom and gearbox and place the bolts thru the clamps and boom. Helicopter started spinning gearbox came off, torque tube came out. Autoed down minor damage, blades and tailboom, one tuff strut. Lesson, "do not forget the bolt"

[Rada70]

GREAT THANKS.