ELA Eclipse wheel failure.

[Doctordantodd]

Eclipse has a tubed tire and I suspect that maybe I had too much pressure. The 3rd (out of 6) screw fractured on take off and I was able to abort. I thought my tire blew, but it was actually the rim. Anyone ever experience this? I noted that one of the six screw on the other side has also lost its head.

 

[Aerofoam]

Sort of surprised to see bolts failing, maybe they were made of chinesium?
It looks like a hardware failure, the actual wheel was secondary after the fasteners failed.
Even standard grade 2 bolts should be able to handle skewed landings, but I would expect grade 5, or AN rated hardware.

 

[Doctordantodd]

Sort of surprised to see bolts failing, maybe they were made of chinesium?
It looks like a hardware failure, the actual wheel was secondary after the fasteners failed.
Even standard grade 2 bolts should be able to handle skewed landings, but I would expect grade 5, or AN rated hardware.

Yea, they are the ELA bolts. Will incorporate a look on preflight now. Had my wheel covers on and honestly hadn't looked in a while.

 

[Vance]

I would replace all the bolts and carefully torque them to the manufactures specification.
I would look carefully at what the problem might be.
The bolts appear to me to be bigger than they need to be so even junk bolts should not have failed if they were properly torqued.
I would add checking the bolt's torque and tire pressure to my preflight check list.
I have found having the correct tire pressure has value.

 

[Abid]

This cannot be because you had a bit too much air in the tire. This is a bolt failure. Can you post a couple of close up pictures of the bolt. As others suggested, I'd replace all the bolts. Given ELA is from Spain they are most likely using metric Class 8.8 hardware (DIN 931 partially threaded with shank).
Here is a link to getting good metric class 8.8 hardware. Most likely it is M6 (6 mm diameter) or M8 (8 mm diameter) bolts with shank and short threads. You won't get short threads in standard hardware so you may have to customize it by getting them cleaning cut in a good band saw. The ends can then be brushed on with some zinc chromate or good paint to prevent rusting. It does not effect the characteristics of the shank of the bolt. If they are AN bolts then you can get them from Aircraft Spruce but you need to know the size.

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[Aerofoam]

Yeah, what he said, I would be replacing all the critical bolts with a known quality and writing a nasty gram to ELA.....
Even if they were not torqued to spec. They should not have failed, they should be the strongest component on the wheel.
If they somehow loosened, I would expect the wheel to start noticeably deforming before the bolts broke.....

 

[Abid]

Yeah, what he said, I would be replacing all the critical bolts with a known quality and writing a nasty gram to ELA.....
Even if they were not torqued to spec. They should not have failed, they should be the strongest component on the wheel.
If the somehow loosened, I would expect the wheel to start noticeably deforming before the bolts broke.....

No. If bolts are over torqued they could give up depending on the over torque.
But generally in such an application as a split rim you just torque them normally and never over tighten. Rims are usually Aluminum. Torque spec for metric hardware class 8.8 can be found easily. Mind you these are Newton Meters and you may have to convert them into foot pounds for your torque wrench. I never bother with torque spec in places like rims. I simply tighten snug and then a quarter to half turn more. This is because I understand what the application is. But it is always good if you don't know or are not sure to stay with torque spec.

Metric Bolts - Tightening Torques

Recommended thightening torque metric bolts.

www.engineeringtoolbox.com

 

[Aerofoam]

No. If bolts are over torqued they could give up depending on the over torque.
But generally in such an application as a split rim you just torque them normally and never over tighten. Rims are usually Aluminum. Torque spec for metric hardware class 8.8 can be found easily

Metric Bolts - Tightening Torques

Recommended thightening torque metric bolts.

www.engineeringtoolbox.com

Yeah, I'm not even considering over torque, you can break any bolt that way, but I would hope anyone tinkering with
airplanes would be able to avoid over torquing a bolt.....

 

[Gyro jeff]

Eclipse has a tubed tire and I suspect that maybe I had too much pressure. The 3rd (out of 6) screw fractured on take off and I was able to abort. I thought my tire blew, but it was actually the rim. Anyone ever experience this? I noted that one of the six screw on the other side has also lost its head.

picture i see looks like bearing failure to me devil in the details

 

[N962GT]

Yeah, I'm not even considering over torque, you can break any bolt that way, but I would hope anyone tinkering with
airplanes would be able to avoid over torquing a bolt.....

Rule of thumb to tighten fasteners on the fly without a torque wrench: They make box and hex wrenches only so long. You are supposed to use this wrench to tighten your nuts and bolts only up to the point where it becomes uncomfortable in the palm of your hand. At that point STOP. Nine times out of 10 when you then check it with a torque wrench you will be within 10% of spec. When you do this enough pretty soon you will be able to feel the right torque to within +/- less than 5%.

Alternative explanation: tire was low, pilot hit a bump or had a bad landing, THEN pumped up the tire and kept flying until the stressed screws failed.

Need to see the complete rim, and need to see the other side as well before drawing any conclusions here.

 

[Doctordantodd]

Was a failure of multiple bolts. Ordered a bunch of new ones from ELA but they are the same quality. Three bolts fractured, the last one I felt. At that point the outer half of the aluminum split rim bent and the tire became very uneven and it felt like a flat. The only real damage was to the outer aluminum portion of the split rim.

I have 200 hours on this plane, fly alone, land softly and weight 160. I have changed the tires once, but just hand tightened them with a standard hand wrench. The bearings and everything else are perfect. I am going to have a local AP look at these bolts and get me some better ones. I really like the Berringer wheels and brakes on my other planes.

 

[Trooper]

Had the 200 hour service been completed? There was a maintenance/safety alert issued for these wheel bots to be replaced as the originals were found somewhat 'lacking' hence the alert to replace them immediately. Then the maintenance/service manual states that these wheel bolts have to be replaced at the 200hr, 400hr, 600hr intervals etc.

 

[Aerofoam]

ELA should be notified, there could be others out there with crap bolts, or maybe bolts that were from a bad lot#.
That kind of failure shouldn't happen...

 

[Roundwing]

It looks like there is little if any shank on those bolts. There should be shank length the thickness of the split rim and the black thing that holds the tire. Otherwise you are putting stress on the threads which are weaker than the shank.

Rick

 

[Aerofoam]

It looks like there is little if any shank on those bolts. There should be shank length the thickness of the split rim and the black thing that holds the tire. Otherwise you are putting stress on the threads which are weaker than the shank.

Rick

That is probably not a significant issue. (I wouldn't be 100% on this one)
I am dealing with studs right now that all broke off at the transition because the point where the shank ends and the threads begin causes
(Stress Riser) where the flexing is concentrated and it causes the failure.
3 out of 11 studs broke off below grade at the thread/shank transition (In an AL head) and I am having to blindly build weld in the hole, then weld nuts on to extract the remaining studs.
I am intentionally using high grade 8mm all thread from McMaster Carr and cutting new all thread studs to eliminate the stress riser.

I think the wheel bolts in this case were either really crap bolts, like the ones in a bin at Home Desperate, or they were faulty bolts that somehow made it to the market...
Any good quality bolt should hold up in this type application.

 

[Abid]

Had the 200 hour service been completed? There was a maintenance/safety alert issued for these wheel bots to be replaced as the originals were found somewhat 'lacking' hence the alert to replace them immediately. Then the maintenance/service manual states that these wheel bolts have to be replaced at the 200hr, 400hr, 600hr intervals etc.

Honestly that’s quite bad. In selling 180 plus aircraft, I have never had to worry about wheel bolts for split rims once without a serious crash.
Rust would or should be the only concern for these in maintenance.

Doctor if they are M8 bolts, you can just figure out the grip length and change them with AN5 bolts. They are so close in diameter that once torqued it wouldn’t even matter and you know you have quality bolts. How does ELA know when other bolts in rest of the structure should be changed if these have to be every 200 or whatever hours. This is the first time I have ever heard of constantly changing wheel to bolts in 20 years of being in light aviation.

 

[j4flyer]

I experienced this on cropduster tailwheels that we’re not serviced. I imagine it would be the same in other applications. What we witnessed was dissimilar metal corrosion from water getting to the bolt. When landing the tire flattens out and would burst the heads off AN bolts holding the rim together. The tailwheels took much more of a beating than the mains.
I’ve also seen them break from over torquing. When serviced we looked for signs of stretching on the bolts. The bolts were a special length on the tailwheels so we tried to keep them in stock. Of course a bad batch of bolts AN (MS) can cause this type of failure too. If an impact tool is used to tighten the bolt, it can stretch the bolt near the head. You can see a different thread pattern when this happens. The threads near the head will have larger spaces between each one. In severe cases you can see a narrowed shank.

 

[Abid]

I experienced this on cropduster tailwheels that we’re not serviced. I imagine it would be the same in other applications. What we witnessed was dissimilar metal corrosion from water getting to the bolt. When landing the tire flattens out and would burst the heads off AN bolts holding the rim together. The tailwheels took much more of a beating than the mains.
I’ve also seen them break from over torquing. When serviced we looked for signs of stretching on the bolts. The bolts were a special length on the tailwheels so we tried to keep them in stock. Of course a bad batch of bolts AN (MS) can cause this type of failure too. If an impact tool is used to tighten the bolt, it can stretch the bolt near the head. You can see a different thread pattern when this happens. The threads near the head will have larger spaces between each one. In severe cases you can see a narrowed shank.

Who uses impact wrench in light aviation. They should be fired immediately.
Yes of course corrosion and rust are a concern for hardware all over. That goes without saying. But this is no crop-dusting gyroplane with chemical being sprayed all around. That alone causes need for many more inspections and much faster replacement cycles due to rust chemicals themselves would cause. Same thing on something like a Searey amphibian airplane but in a gyroplane flown from airports on nose wheels? That does not make any sense. It seems like ELA is not confident about the source of their hardware. I can see getting a single bad batch and that should mean replacement once and correcting the source so it does not happen again. What I do not get is requirements of changing these bolts blindly not on condition every 200 hours.

 

[Roundwing]

That is probably not a significant issue. (I wouldn't be 100% on this one)
I am dealing with studs right now that all broke off at the transition because the point where the shank ends and the threads begin causes
(Stress Riser) where the flexing is concentrated and it causes the failure.
3 out of 11 studs broke off below grade at the thread/shank transition (In an AL head) and I am having to blindly build weld in the hole, then weld nuts on to extract the remaining studs.
I am intentionally using high grade 8mm all thread from McMaster Carr and cutting new all thread studs to eliminate the stress riser.

I think the wheel bolts in this case were either really crap bolts, like the ones in a bin at Home Desperate, or they were faulty bolts that somehow made it to the market...
Any good quality bolt should hold up in this type application.

Snap On makes left handed drill bit and extractors that may help get the remaining bolts out.
If it is not too tight the left handed drill bit will sometimes catch and unscrew it.
Care has to be taken so as not mess up the original threads.

Rick

 

[Aerofoam]

Snap On makes left handed drill bit and extractors that may help get the remaining bolts out.
If it is not too tight the left handed drill bit will sometimes catch and unscrew it.
Care has to be taken so as not mess up the original threads.

Rick

I am trying to avoid drilling because it's in the rear of the compartment in a tight space and I will have to get a 90 deg. adapter and build a fixture with drill guides to stay centered.
There are water passages on all sides and only enough surface to drill for an 8mm Timesert if something goes wrong.
I do have reverse drills from McMaster Carr and an extractor. The only positive thing is that the studs are not stuck, they seem to come out easily
once you get a grip on them...
I haven't done the nut welding before and I don't weld often enough to be very good at it, but I did 10 practice studs in a 1/4" AL. plate
before attacking the head and the process is fairly simple.
The first real one went well, the second one broke off twice and I am re-visiting it today.
I decked the manifold on a belt sander yesterday to take out a 0.030 warp, so it's ready to go back in when I get the studs sorted out...