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Pro work on everything, as always.
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Feb 11, 2017 20:30
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kevbarlas posted:
Full disclosure, I'm not a cage builder, I'm just an engineer. And I'm not 100% certain I'm reading it right about what you're planning, either... If that mount is meant to hold the roll cage main hoop for the interior though I'd be a bit worried. It's cantilevered like that and I don't think it's going to like taking the vertical load when that member is at an angle like that. (If that makes any sense) Maybe you plan to add more to it (like below), I don't know. Even then it's probably not ideal but much stronger than before. 
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Feb 11, 2017 21:02
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Wouldn't it be better to have a crossmember between the framerails under the mount holes and have vertical posts come up? It elminates the cantilever, sorta, and gusseting could help counteract sideways forces. I'd consider an x-shape for the cross as well. Any of this is going to do strange things to the rigidity of the frame too. If there isn't any crossmember within a few inches of the mounts, they could potentially squish the frame out sideways in both directions during say a rollover.
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Feb 11, 2017 21:10
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Larrymer posted:Full disclosure, I'm not a cage builder, I'm just an engineer. And I'm not 100% certain I'm reading it right about what you're planning, either... Yes i was thinking something like that. Also some kind of bar to join the 2 inner parts together too. By that i mean the part the brace is joined to and the other one. Also, the roll cage hoop at that point will have a diagonal going all the way down through the wheel arch area to join to the front of the cage. Guess it would be like a door brace so that should also add strength. kevbarlas fucked around with this message at 21:25 on Feb 11, 2017 |
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Feb 11, 2017 21:22
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Yanno, I've been thinking about this a bit, and the same full disclosure here, I'm not a cage builder, and at best, I dropped out of an engineering program in college and did computer poo poo. But I like to think I have a basic understanding of stresses and force. Kev, maybe a rollcage isn't the best of plans. I think you're going to need to make parts of the cage from lighter material, specifically so they will fail during a collision without compromising its integrity. Like I said before, it's going to alter the rigidity of the frame and completely change how the vehicle does react in a collision. A good strong and braced-to-gently caress cage will definitely keep the cabin uncrushed, but this van also doesn't have any real way of disappating the energy from a crash aside from the body and frame. A cage is an extension of the frame, and I believe ultimately its design should account for the crash dynamics of the altered vehicle. If the desire is to improve safety in something like your van, it should incorporate features to disappate crash energy, otherwise those forces will be transfered to you and anything inside it. tl;dr: What I'm saying is you need to build crumple-zones and I don't think it's going to be that easy to do. Fermented Tinal fucked around with this message at 22:16 on Feb 11, 2017 |
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Feb 11, 2017 22:10
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I would think that the cage would provide great protection in a roll-over, which a camper van is definitely at risk for. And while it may not provide energy dissipation, I'd rather take the chance of whiplash and internal injuries over the certain cabin penetration you'd have in an old rear end van like that. Just my thoughts. Also not an engineer, only a worthless civil engineering associates degree.
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Feb 11, 2017 22:59
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The other one with body on frame is that you get a LOT of movement between the body and frame from the soft body mounts- I know on my 4wd's it looks like the bullbar is about to fall off on bad roads but thats just the chassis moving independently to the body giving that illusion. Dont know how you would get around it without going for rigid body mounts which impart a LOT of NVH into the body and can also crack the mounts out on the bodywork (big problem with hilux's when you put a body lift into them and dont include the original soft rubber mount on top of the alloy lift puck)
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Feb 11, 2017 23:14
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I get where you are coming from fermented tinal. I would be thinking the same if i was building this van for proper track days or totally redesigning it on a serious budget , but....angryrobots posted:I would think that the cage would provide great protection in a roll-over, which a camper van is definitely at risk for. This is pretty much what im thinking though. Im not looking to build a cage that will protect my life in a 100mph crash. Its just, as the van is right now then im pretty much the crumple zone already. Between me and the outside is really just a sheet of 1.2mm thick metal, theres nothing else. If i can make some kind of cage and bracing that should anything happen, even say a crash at 20mph, would help to protect my legs or head. I do intend on having differant seats with head rests and a proper harness to keep me and passangers in place. Theres a guy on this forum i visit that has a crashed ford thames. Says someone was coming the other way at a junction and cut it short so that would have been maybe 15-25mph or so? Now if he was going a bit faster then by the looks of it his legs would have been crushed. Theres a few pictures of it here. http://www.mig-welding.co.uk/forum/threads/my-ford-thames-400e-van.9476/ Theres just no consideration for safety in vans like these, if i can do something to help increase my chances of living or preventing lost limbs then i think il do it.
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Feb 11, 2017 23:26
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Yeah, honestly it looks like there's more room and tin in my trash can than the footwell of your van. I can get where you're coming from, just don't forget there is still a shitload of energy involved even at low speeds. Gusset every important joint.
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Feb 11, 2017 23:36
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kevbarlas posted:fermented tinal I want whatever phone you have 
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Feb 12, 2017 00:36
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Pomp and Circumcized posted:I want whatever phone you have That's my name?
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Feb 12, 2017 01:57
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Can you do a sketch to show what you have in mind? I havent quite visualised what that mount does or directions etc. I know what we do with full blown cages and FIA certification is over the top for you but I think we can critique if you want. Now while the comments about crumple zones are right, a proper cage more or less doesnt crumple - it redirects energy away from the occupants. This is what I would be looking for. A drawing even back of a napkin would be fine - this is something you really do want to have drawn out. The comments about "okay I'm fine with the risk of whiplash etc, I dont want cabin intrusion" is a good point, that's the best you are going to get. One of the not often discussed things about a cage is that it's designed to explicitly extend the time of the crash to the point where G-forces are hopefully lowered so it replaces what crumple zones do - hitting a wall head on you will be SOL anyway but in other circumstances doing what you can to extend accident time is going to more htan likely help.
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Feb 12, 2017 02:27
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I would need to see a design of how you want the cage, but ATM all you need is to put a stump bar(floor bar) and that looks fine. Remember that before this era of bird cages a single Roll hoop made of alloy or 2.5 mm and pair of rear legs was considered plenty. There was not that many fatalities in Top levels of rallying. It took the invention of huge grip and stupendous power. Birdcages came into vogue when tyres became sticky. There was a time you could make a car too stiff! You will find a plain loop is plenty strong enough for a single impact. Kaptainballistik fucked around with this message at 04:44 on Feb 12, 2017 |
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Feb 12, 2017 04:41
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How much weight is being added? I assume the Lexus engine is a lot more powerful than whatever was stock for this van, but I feel like we're looking at a lot of added steel. That doesn't just matter for power. The tires for example need to be able to handle the lateral loading when you corner.
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Feb 12, 2017 05:51
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Would it be possible to make a cage mounted to the body (not frame) to which the seats, seatbelt etc were securely mounted, but was designed to separate from the structure of the vehicle during a crash? I.e. Instead of making the body of the vehicle stronger, accept that the body will crumble, and fit an internal birdcage for the passengers whose integrity is not related to that if the rest of the vehicle. In the case of the crash, let's say the front 20cm of the vehicle is smashed, but the passenger cage would move 20cm backwards inside the body. This would prevent intrusion, but also prevent the passengers getting the full g forces of the crash. The remaining risk I can see is being impaled by the steering wheel from in front, or by a bed frame from behind, but I think these risks could be designed out. I.e. Mount steering wheel to the cage, and a short bulkhead behind the seat. I'm sure there are other reasons why this is a bad idea, but I can't think of them. stump fucked around with this message at 11:47 on Feb 12, 2017 |
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Feb 12, 2017 11:44
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With reference to the chassis/body movement mentioned above, I think as long as you leave enough separation fron the cage contacting anything, it shouldn't be a massive problem, but I like Stump's idea of just having a standalone cage in the cabin; that'd give you a "safety cell" without tying the chassis hard to the body, and ultimately, any accident big enough for it to matter is going to trash everything anyway, and you also start getting into how well secured your own personal meatbag is to the seat etc. But yes, the entire "cell" staying together, with the seats(and you) firmly attached, should have the same effect as a crumple zone. For the steering column, perhaps including a collapsible section from a modern car might be a good idea? Kaptainballistik posted:I would need to see a design of how you want the cage, but ATM all you need is to put a stump bar(floor bar) and that looks fine. Ultimately, I think it's important to remember it's a 60 year old design of a utility vehicle, and unless you radically alter stuff, accidents being more likely to maim or kill you just comes with the territory. While it'll shrug off minor nudges, I would not want to have a big stack in the Land Rover, but that'll never stop me driving/enjoying it.
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Feb 12, 2017 12:37
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Leperflesh posted:How much weight is being added? I assume the Lexus engine is a lot more powerful than whatever was stock for this van, but I feel like we're looking at a lot of added steel. Remember that this vehicle was originally designed to be loaded to the roof with cargo/tools/etc, also IIRC he's banded the wheels so there's going to be a bit more of a substantial tire on it.
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Feb 12, 2017 15:58
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stump posted:This would prevent intrusion, but also prevent the passengers getting the full g forces of the crash. Wouldn't this actually do the opposite? I'm not a mechanical engineer, and I might be thinking about this all retarded, but if you go from "decelerating as the body deforms" to "decelerating to zero and then accelerating backwards as your cage is punted around," doesn't that add extra g-force for the passenger? I don't see how that's any better for the occupant than having the same cage tied to the body.
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Feb 12, 2017 23:08
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Raluek posted:Wouldn't this actually do the opposite? I'm not a mechanical engineer, and I might be thinking about this all retarded, but if you go from "decelerating as the body deforms" to "decelerating to zero and then accelerating backwards as your cage is punted around," doesn't that add extra g-force for the passenger? I don't see how that's any better for the occupant than having the same cage tied to the body. I'm not an mech engineer either, so take this with a pinch of salt. There wouldn't be any backwards acceleration that I can think of. I just described it poorly - it wouldn't really move backwards, but it would allow the van to crumple naturally, dissipating energy, while keeping the passengers from getting crushed. It would work better in an offset collision - in a full frontal crash there wouldn't be much chance of disappearing energy, but it would still keep the occupants in roughly the correct shape. They would be under higher g forces than with no cage (however in that case the crumple zone would be their knees) but lesser g forces than if they were attached directly to the chassis.
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Feb 12, 2017 23:42
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InitialDave posted:
I am a FIA certified Rollcage constructor after all 😉 I think the collapsible steering column is a good idea. There is the added advantage of modern controls and the ability to utilise Intermittent wipers and the like with more ease. If you can reinforce the toe board with box section that would also be helpful. The majority of injuries in frontal control vans is your feet being crushed. Kaptainballistik fucked around with this message at 03:05 on Feb 13, 2017 |
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Feb 13, 2017 03:01
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Probably pick up a few good tips watching what they're doing to the mini on project binky too- IIRC they've done crush cans for the front, side intrusion bars and a collapsible column
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Feb 13, 2017 03:41
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Steering wheel is drat near horizontal in this thing, column is like 15 degrees from vertical. Does it really need to be collapsible?
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Feb 13, 2017 03:45
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No but the wheel might need to be? 
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Feb 13, 2017 09:51
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Save time, just wear full hockey gear whilst driving. That or this... https://www.youtube.com/watch?v=9WWiPiks1sU
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Feb 13, 2017 10:26
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Kaptainballistik posted:I am a FIA certified Rollcage constructor after all 😉
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Feb 13, 2017 17:51
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InitialDave posted:"Cage builders do it at unconventional angles."
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Feb 13, 2017 17:58
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Fermented Tinal posted:That's my name? I saw Ferremit's name above and wanted to believe, OK Mr.-Autocorrect-name?! 
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Feb 13, 2017 21:49
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InitialDave posted:"Cage builders do it in the cabin."
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Feb 13, 2017 22:30
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InitialDave posted:"Cage builders don't lay pipe"
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Feb 14, 2017 01:32
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Hey Kev, Ebay's got a competition to win £4k to spend (on Ebay) doing a car restoration, entries have to be in by tomorrow night. The ground rules are vehicles over 40 years old, you have to buy stuff on Ebay, do all the work yourself, and they'll be choosing projects based on what's "interesting" - I think your Dad's Minor - especially with the story behind it - could really be in with a shout on that basis, and between you and him you could do a hell of a lot. http://www.ebay.co.uk/gds/eBay-Car-Challenge-2017-Terms-Conditions-/10000000208931933/g.html
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Feb 19, 2017 00:47
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InitialDave posted:Hey Kev, Ebay's got a competition to win £4k to spend (on Ebay) doing a car restoration, entries have to be in by tomorrow night. Maybe try PMing Kev - he was always quick to reply to my messages.
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Feb 19, 2017 00:53
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Pomp and Circumcized posted:Maybe try PMing Kev - he was always quick to reply to my messages.
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Feb 19, 2017 01:04
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Thanks for the heads up guys but on closer inspection it says the restoration must be done by 10 July 2017 , i dont think we will have even started anything major on the car by then. Thanks again though  .
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Feb 19, 2017 18:48
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kevbarlas posted:Thanks for the heads up guys but on closer inspection it says the restoration must be done by 10 July 2017 , i dont think we will have even started anything major on the car by then. Thanks again though
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Feb 19, 2017 19:01
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kevbarlas posted:Thanks for the heads up guys but on closer inspection it says the restoration must be done by 10 July 2017 , i dont think we will have even started anything major on the car by then. Thanks again though Use the cash to buy a second welder and dual-wield.
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Feb 19, 2017 19:28
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Pomp and Circumcized posted:Use the cash to buy a second welder and dual-
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Feb 19, 2017 22:11
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kevbarlas posted:Thanks for the heads up guys but on closer inspection it says the restoration must be done by 10 July 2017 , i dont think we will have even started anything major on the car by then. Thanks again though Well you wont with that attitude
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Feb 19, 2017 22:28
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| # ? Apr 26, 2024 06:11 |
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A visit to a firetruck museum (the kid went nuts) and this 1957 Ford Thames 501 made me think of this thread. Hope you're alive, Kev!
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Apr 17, 2017 12:00
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