hose clamp failure

[Graeme Smith]

Sadly today another RW accident, this time it was the rubber hose coming off the U shape aluminium pipe feeding the heads, the hose blew off on final approach about 20 feet in the air up till this point all temperatures had been in the green, the engine faltered as it was sprayed with coolant. The pilot managed to get it to the ground with some great piloting skill by keeping forward momentum as the RW hit the ground, the landing hoops folded backwards and cushioned the hard landing. The landing gear did what it was designed to do fold back and absorb some of the impact, so all that was damaged was the landing hoops and skids, it makes me realise that if those hoops had been reversed the damage would have been a lot more as it probably also would of damaged the frame and whatever was attached to that frame

[Orv Neisingh]

Or if the pilot had reversed the front hoop, lengthened and reinforced the skids he very well may have been able to just slide the helicopter onto the ground with no damage as I have done several times during an engine/mechanical failure. In over 13,000 hours of flying these ships and most of those hours were flown with the reinforced longer skid configuration, those longer skids and reversed hoops have saved many Rotorways from rocking forward and onto their left sides at forward ground contact. To each their own cup of tea Graeme. Just don't authoritatively tell everyone that the reversed front bow and longer reinforced skids is a bad idea, it is not. I present the facts on my website and let the owner/pilot decide what is best for them.

https://rotorwayforums.com/flywithorv/ww...ggear.html

If the pilot came down vertically that hard the reversed front bow would simply spread out to the side absorbing the download. Glad the pilot is OK.

[Geno Mancini]

There needs to be a more aggressive shoulder on those aluminum tubes.
And, the hose clamp needs to be compleatly one the proper side of that shoulder.
I've seen hoses slip off of tubes many times if not done properly.
Also the bolt style clamps are better than the worm gear clamps, they done come lose over time.

[Lyle Swallows]

Was this one flying with your Electric Fan conversion? 

I also see this is at a coolant hose area that is subjected to vibration/torsional flex from the moving engine to the stationary coolant pump/radiator. maybe there was a preload or not enough flex in the system and it wiggled its way out. 

how fresh is that rubber hose? is at all stiff due to heat cycling next to the exhaust?

Lastly i love seeing the langing gear do its job! i personally am using the original gear setup with extended reinforced skids, i think it looks better, and i like the idea of the additional mechanical absorption apart from just normal spreading aswell. as for the reverse gear i agree it is more robust, but that stress must get transfered somewhere. 

at the end of the day i think to each their own, no crash is the same and we cant predict the nature of our forced landing or forced landing terrain. 90% of certified helicopters have their cross tubes straight up and down fore and aft and only rely on spread, so our forward or backwards hoop is kinda silly to debate. 

let us know when this one gets back in the air Graeme! i want to see more content of your conversions flying!

[Graeme Smith]

Hi Lyle, yes this was one of my electric fan, electric water pump and side scoops. My first attempt at the side openings, which later we discovered needed some side scoops to function properly
All temperatures have been perfect with all fans turning off once in forward flight and the water and oil both in the green.
When he flew into my place and overhead of me I saw green coolant start coming out of the overflow hose from the surge tank, so I knew something was wrong, he was a little high and a little slow and he was on the ground from that sighting in about 10 seconds, The pilot said just as he was coming in and about 5 foot off the ground he heard a loud bang and he started to rotate he nosed forward and applied pedal and landed hard, he exited the RW and what looked like smoke started pouring out of everywhere we both backed off but we then concluded it was steam and it was everywhere.

He walked away un scathed, there is a GoPro recording I think, so maybe it will tell us something when I get to view it.

The hose was in good shape it just blew off, maybe the hose clamp failed or became loose not sure we might start delving deeper today after all it was Father's day yesterday so dismantling a damaged RW was not at the top of our lists, I am just grateful it did not hurt anyone, and grateful it had the std landing gear.

I know I will be looking for an answer and will see if there are better hose clamps we can reassemble with if the clamp has failed. Or it could simply be no-one re checked all the hoses after the 25hours of running.

[Geno Mancini]

There needs to be a more aggressive shoulder on those aluminum tubes.

[Homer Bell]

Those tubes have a big flange on them as I recall. Manu times the builder will get the clamp installed in the wrong location allowing the hose to come off.
As for the landing gear, I’ve always said tell me how you’re going to crash and I’ll tell you which gear I want. With straight legs forward as hard as he apparently hit would have just transferred the load to the frame and it would be damaged up top, WHICH MAYBE ALREADY! I’ll bet the frame tubes may be crushed from the front hoop rotating up and into the bottom of the frame tube. Have seen it more than once. Found one rebuilt ship that they had filled the crushed tube with bondo and painted over it!!
The front hoop is bolted to the frame horizontally. The only thing keeping it from rotating is the bottom of the frame tube and the skids themselves. This is why you see ships with the skids bowed up in the middle. One too many hard landings.
Any style gear will allow run on landings. The biggest problem is in a real engine out forced landing for pilots who haven’t practiced autos is, they are always trying to stop that last few mph of forward speed and hit with the nose UP! NOT FLAT! Then the ship rocks up on the front skids and if it’s too hard, the skids can break. If they don’t break then it will rock back and many times hit the tail rotor. Somewhere there is video of that exact thing happening to me after the engine quit after a power recovery auto attempt when I rolled power on quickly and the carburetor engine coughed and died. You can me pull back on the stick and lift the nose trying to bleed off that last little bit of speed I had just after the engine died. If I had just held the attitude I had it would have been a perfect full touch down auto, nice and flat with a little slide.

[Homer Bell]

For the last several years the factory had steel tubes inside both pilot and passenger skids back past the front hoop mount. If you break one of those skids off, you really hit pretty hard.
It’s going to be interesting to see how the new factory style gear holds up with hard landings. Its ability to transfer the load to the center section like the Robbie’s do will probably change where the damage shows up. The new gear has 6 individual parts. You might not have to change out the whole hoop now if you damage just a part or two parts of it. I need to weigh the parts of the new gear and see how much weight has been added. It feels pretty heavy and the brackettry welded on the frame is massive.

[Geno Mancini]

I've always liked how JetRanger does their landing gear.
The landing gear does not go into the body of the helicopter.
It's attached with saddle clamps, outside the body.