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ouR escaPOD mods |
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StephenH 
podders Helping podders - pHp 
Joined: 29 Nov 2015 Location: Wake Forest, NC Online Status: Offline Posts: 6423 |
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 Topic: ouR escaPOD modsPosted: 07 Nov 2020 at 1:27pm |
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Yes, that is the area. I expect that the hide-a-spare will serve the purpose with the exception that it is more flexible than the brace I installed. It can bounce some, but overall, if it is tight against the bottom, it will provide support.
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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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GlueGuy
Senior Member
Joined: 15 May 2017 Location: N. California Online Status: Offline Posts: 2708 |
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Posted: 07 Nov 2020 at 9:31am |
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StephenH, is that the area underneath the kitchen?
Reason I ask is because that's exactly where we put our hide-a-spare, and because of the limited space, the spare tire pushes up very firmly against the floor. I'm thinking the hide-a-spare/spare tire pretty much accomplishes the same function?
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bp
2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost |
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StephenH
podders Helping podders - pHp
Joined: 29 Nov 2015 Location: Wake Forest, NC Online Status: Offline Posts: 6423 |
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Posted: 06 Nov 2020 at 12:35pm |
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Thanks to John T, I now have a cross-brace under the floor of our RPod to prevent the problem John M. detailed. Since John T lives near me, he had a shop fabricate two tubes with end plates. Mine was sized to fit the space on our RPod. His is slightly longer. (again, let no two pods be built the same seems to apply). I cleaned it up and painted it. This morning I installed it. The shop put 5 holes in the mounting plates, but I only used 3 of them, thinking that it should be sufficient since this is to strengthen the floor, not carry the entire load. Here are a couple of pictures:   This is a preventative measure. Our floor is still pretty good. This is to support it to hopefully prevent the problems John M. had. Ours supports the existing floor without the additional layer that the factory put on John M.'s 'Pod.
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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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offgrid
Senior Member
Joined: 23 Jul 2018 Online Status: Offline Posts: 5290 |
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Posted: 19 Aug 2020 at 7:14pm |
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Ok, I found my post from last fall on this. Looks like I suggested reinforcing with 2x2x0.1 tubes up front and 4x2x0.1's at the axle. Probably I was thinking that would keep the weight down and ground clearance higher in the front, plus the loading on the frame isn't as bad there as at the axle. The riser kit adds 3.5 inches anyway so the 4 inches is pretty much equivalent.
Here it is: Ok, I ran the numbers for the combined beam case. The formula for adding two asymentrical shapes together turned out to be a little tricky. I assumed a uniformly loaded frame from the tongue to the rear of trailer beams and a 3800 lb total weight. That's not really right but it simplifies the problem quite a bit and its not terribly far off.
That puts the two max stress points at the axle and at a point about 58 inches aft of the ball. The stress is about half as much at the 58 inch point as it is at the axle. I get a 2G load capacity factor at the axle and 4G at the 58 inch point when I add the 2x2x3/16 tube under the 4x2x0.1 tube. If it were me, I'd stack 2x2x0.1 tubes in the front and use 2x4x0.1 tubes at the axle. That bumps the safety factor up to about 3G at throughout. You should have room to add the 4 inch tubes, they will add roughly the same height to the trailer as the riser kit does. I would make the length of the axle area frame reinforcement pieces 66 inches long and start them 28 inches in front of the axle, ending 38 inches behind it. I would make the 2x2 tongue area reinforcement pieces 78 inches long and start them 18 inches back from the hitch, ending 8 ft behind it. Total weight increase would be about 80 lbs. |
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1994 Chinook Concourse
1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
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DavMar
Senior Member
Joined: 04 Aug 2017 Location: Lexington, NC Online Status: Offline Posts: 592 |
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Posted: 19 Aug 2020 at 5:53pm |
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offgrid, thanks for the information. As I said I would like to see a write up on a tongue and other frame modifications by someone before I tried to tackle the task. I would have no problem with the idea of rising the Pod 4" if you were to raise the frame under the axle though I might then look into new entrance steps to add a step. Or adding a section of box beam under the tongue as you suggested but it would sure be nice to know exactly the length and placement of the steel, ect. before a novice like myself would even attempted to contract with a welder to do this great modification.
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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: 19 Aug 2020 at 12:35pm |
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I'm not a structural engineer and my degree is in physics but I have done a lot of engineering and managed structural engineers and construction projects quite a bit. So, I usually know enough to get by with simple beam analysis like this. The simplification is to assume that the frame is uniformly loaded, after that its pretty straightforward.
I don't know that anyone has proactively reinforced their frame but at least one member has had a frame failure and it was at the rear axle where you would expect it to be. That was olddawgsrule and I think Lippert fixed his frame in that area by welding on another 4x2 tube under the existing one. That's what I'd do, take a piece of the same 4x2x0.1 inch material and weld it to the existing tube under the axle, then reattach the axle to that. That roughly triples the strength of the tube in that area. It would also act as a riser kit. Ditto in the front where the max stress is actually under the trailer box a bit not at the tongue itself. You don't need to run the tube very far forward of the axle or very far forward on the tongue, you can see from the diagram that the stress drops off pretty fast. Sometime last year I did an estimate on where to start and stop the doubled tube, you could probably find it in a search.
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1994 Chinook Concourse
1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
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DavMar
Senior Member
Joined: 04 Aug 2017 Location: Lexington, NC Online Status: Offline Posts: 592 |
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Posted: 19 Aug 2020 at 12:06pm |
Offgrid, you must be a structural engineer or have a deep background in engineering? I read your post and looked over the formula you posted a link to but sadly it all looks like Greek to me. I would seriously like to "beef" up my trailer tongue since I added dual gas tanks and a tool box to enclose the battery and storage on the tongue. What I'd like to see is someone who has done this mod, what size steel they used and where is all welded on the frame, ect? I'd also like to see about the possibility of adding a rear cargo carrying storage and keep the hitch receptacle for the spare tire and tie the storage tray to the frame.
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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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DavMar
Senior Member
Joined: 04 Aug 2017 Location: Lexington, NC Online Status: Offline Posts: 592 |
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Posted: 19 Aug 2020 at 11:52am |
Stephen, I know this is totally off the subject (so please everyone forgive me) but who in your area is doing examinations now??? I know my club FARC, Forsyth Amateur Radio Club out of Winston Salem is no longer testing due to the Covid 19 virus along with all the other radio clubs in the surrounding counties. Good luck on the test, its pretty easy with mostly just rules and regulations, for the technical license. If you ever hear the call sign on air of KN4VBT that's me! I really need to get my extra license so I can get a one by three call sign but without anyone locally giving the test and being so busy repairing vintage radios don't have time now to the little I need to get the license.
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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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StephenH
podders Helping podders - pHp
Joined: 29 Nov 2015 Location: Wake Forest, NC Online Status: Offline Posts: 6423 |
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Posted: 19 Aug 2020 at 10:51am |
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I think I will skip that for now. I am studying to take a Technician Class Amateur Radio License exam this coming Saturday. That is priority for right now.
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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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offgrid
Senior Member
Joined: 23 Jul 2018 Online Status: Offline Posts: 5290 |
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Posted: 19 Aug 2020 at 8:08am |
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Yep, and if you want to check beam bending stress yourself you can use this calculator to find the section modulus about the x-x axis for the 4x2x0.1 tubes. Should be about 1.2 in^3.
Then bending stress is M/S. Check both M1 and M2. Yield for mild steel is generally taken to be 36ksi. Don't forget to divide by 2 (two beams) but also multiply by at least 2, preferably 3, for bump loads. |
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1994 Chinook Concourse
1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
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