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ouR escaPOD mods |
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DavMar 
Senior Member 
Joined: 04 Aug 2017 Location: Lexington, NC Online Status: Offline Posts: 592 |
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 Topic: ouR escaPOD modsPosted: 04 Jun 2019 at 10:37pm |
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Maybe I’m naïve but if there is a worry about water collecting
in the bottom of the V channel of the angle iron why not drill a couple of small weep
holes in it? I don’t know if it would affect the strength of this steel brace but I don't believe it would. On a side note I'm looking very forward to reports on how this axle mod has worked out in real use over time. |
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Dave & Marlene J with Zoey the
wonder dog. 2017 Rpod 180 2016 Toyota Tacoma SR5 4x4 Lexington, NC |
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offgrid
Senior Member
Joined: 23 Jul 2018 Online Status: Offline Posts: 5290 |
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Posted: 05 Jun 2019 at 7:41am |
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Drain holes kept small say 1/8 inch won't be significant structurally but there's not really a channel open under there to carry water to them, the angle is up against the axle. So I don't know that they'd do much good either.
Barring something strange like the angle sliding side ways or falling off don't expect anything definitive to come from one or two field uses. That's because the failure rate of our axles is fairly low to begin with. I like to exercise my brain so here are some numbers. Lets say there are 10,000 rpods on the road and they've been sold for 10 years (average age 5 years) so there are roughly 50,000 rPod-years of product history out there now. Let's say that there have been 1,000 axle failures in that time (just a wild guess on my part), so that's a 1000/50000 or a 2% per year failure rate with the existing axle, or a 20% failure rate over 10 years. These aren't the right numbers of course but they're probably not way off the mark either. Most folks don't experience axle failures, but a significant number do. What would success look like for an axle reinforcement? Lets say we want to cut that 2% down by a factor of 10 and get a 10X reliability improvement, for a 0.2% annual axle failure rate or 2% over 10 years. How many field trials would you need to run to prove that? The math used to do that kind of failure analysis is called the binomial distribution. If you run that calc for this case it turns out that if you want to be 80% confident that you've taken the failure rate down to 0.2% per rPod-year then you'd need to run about 800 trials (800 rPods for a year or 400 for 2 years for example) and have zero axle failures. So, to prove anything definitive from field testing we'd need to get about 10% of our 8000 members to do the mod, tow for a year, and report back that their axles were all still good. As we say in engineering, that ain't gonna happen.  So, we need to depend on the structural calculations instead. Those show a significant (about 50% increase) in load capacity of the axle tube from adding the reinforcement. It doesn't do anything to help with the potential to have bent torque arms, spindles, or crushed rubber cords though.
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1994 Chinook Concourse
1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
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StephenH
podders Helping podders - pHp
Joined: 29 Nov 2015 Location: Wake Forest, NC Online Status: Offline Posts: 6285 |
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Posted: 05 Jun 2019 at 10:21am |
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I don't think weep holes will be needed. The bottom of the axle tube has a curve but the steel angle does not have that curve so there is a space on the bottom of the angle. Given that the axle tube is highest in the center and slopes down toward the wheels and that water does not run uphill, any water that may get inside should naturally flow outward toward the wheels where it will be able to drip out through the space between the axle tube and the peak of the steel angle. Even though this picture is blurry, it should show what I am describing.
On a
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StephenH
Happy is the man that findeth wisdom,... ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
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lostagain
Senior Member
Joined: 06 Sep 2016 Location: Quaker Hill, CT Online Status: Offline Posts: 2586 |
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Posted: 05 Jun 2019 at 3:43pm |
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Waddaya mean water doesn't run up hill? At the Mystery Spot near Santa Cruz it does.
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Never leave footprints behind.
Fred & Maria Kearney Sonoma 167RB Our Pod 172 2019 Ford F-150 4x4 2.7 EcoBoost |
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StephenH
podders Helping podders - pHp
Joined: 29 Nov 2015 Location: Wake Forest, NC Online Status: Offline Posts: 6285 |
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Posted: 05 Jun 2019 at 3:59pm |
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It probably appears to be running uphill. It is like some of the "magnetic" roads where it looks like a car is being pulled uphill. It is an optical illusion though. Mystery Hill in Boone, NC is one such example. (see also Gravity Hills).
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StephenH
Happy is the man that findeth wisdom,... ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
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lostagain
Senior Member
Joined: 06 Sep 2016 Location: Quaker Hill, CT Online Status: Offline Posts: 2586 |
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Posted: 05 Jun 2019 at 5:50pm |
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I can understand a Mystery Hill in NC being full of optical illusions, but not the Mystery Spot near Santa Cruz. There all the stuff is true.
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Never leave footprints behind.
Fred & Maria Kearney Sonoma 167RB Our Pod 172 2019 Ford F-150 4x4 2.7 EcoBoost |
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crw8sr
Senior Member
Joined: 12 Oct 2017 Location: Omaha Nebraska Online Status: Offline Posts: 328 |
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Posted: 05 Jun 2019 at 6:09pm |
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Darn StephenH you ruin it! I thought that was real.
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Chuck & Lyn
Izzy, Morkie. RIP Zoe Joy & Gracie, Yorkie 2018 R Pod 190 2019 Traverse In moments of adversity;when life's a total wreck, I think of those worse off than me and really feel like heck. |
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offgrid
Senior Member
Joined: 23 Jul 2018 Online Status: Offline Posts: 5290 |
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Posted: 05 Jun 2019 at 7:27pm |
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I brought my iPhone into the Santa Cruz mystery spot and was using it as a level to measure the buildings and I had to fight them off so they wouldn’t take it away from me. It’s difficult to tell if something is level or not when it’s on the side of a steep hill, which is where the mystery spot is. So maybe the effects there aren’t quite as real as all that.
Water does run uphill though, it’s called capillary action (aka wicking) and can easily wet surfaces inches higher than the water level when the surfaces are close together. So a little 3/8 inch height difference between the ends and the middle of the axle will almost certainly get wet. |
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1994 Chinook Concourse
1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
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StephenH
podders Helping podders - pHp
Joined: 29 Nov 2015 Location: Wake Forest, NC Online Status: Offline Posts: 6285 |
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Posted: 06 Jun 2019 at 1:45pm |
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Yes, capillary action is the exception although it only takes place in certain circumstances where the water is drawn uphill. As a general rule, water does only run downhill.The space between the curve at the bottom of the axle and the V of the reinforcement is enough so that I don't expect capillary action to stop water that gets into the bottom to be affected, but it might along the flat parts that are in contact. That is why the angle got multiple coats of primer/paint and I made sure to touch the axle up before joining the parts together. I'm thinking of squirting a little expanding foam into the square channels to fill them and keep water out of them.
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StephenH
Happy is the man that findeth wisdom,... ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
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marwayne
Senior Member
Joined: 25 Oct 2011 Location: Edmonton AB Can Online Status: Offline Posts: 1002 |
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Posted: 06 Jun 2019 at 2:51pm |
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SH, if you close the ends with foam you are creating a new problem. The water that will seep in between the axle on the angle iron will be trapped in the opening at the bottom. If you leave it open you can blow some air through every once in while so it can dry out,
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If you want something done right, do it yourself.
2011 RP172, 2016 Tundra 5.7 Litre, Ltd. |
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