Lewis Posted February 7, 2007 Share Posted February 7, 2007 I know this has been discussed a lot lately but all the folks doing them lately seem to be keeping most of the original wings, which i'm not fussed about I need to build tubed wings for the 90 - the 110 is getting them too but I'm trying to pay someone to do those - I dont really mind about chopping the front of the car up, and I would rather have ultimate strength rather than keeping the Defender looks Below is a couple of back-of-the-snap-on-reciept sketches I did with the wax crayons last night, can anyone spot any obvious flaws with either of them, and can anyone recommend one design over the other, or where to add gussets/tubework? Cheers Lewis Quote Link to comment Share on other sites More sharing options...
white90 Posted February 7, 2007 Share Posted February 7, 2007 my concern with both would be a hit on either wing bar will affect the other side transferring the force across the front support bar. Quote Link to comment Share on other sites More sharing options...
Mark90 Posted February 7, 2007 Share Posted February 7, 2007 If you are keeping it road legal then you need to consider lights (or a daylight only MOT). The top design, which I like best, makes it more tricky, still doable (look at the like of Bob Seaman's truck - I think that's right) just needs a bit more thought/work. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 7, 2007 Share Posted February 7, 2007 I would say Mr Bish is the expert on this. But my 2p worth is that given the front end or either side of the front end has a really good thump, the forces are going to bend the roll bar down tube as it is mounted high up and on its own. Wheel travel allowing I would say add an extar tube to the centre part of the wing bar top and take it to the base (or low) to the roll bar down tube, this triangulation would add a mass of strength ? nige Quote Link to comment Share on other sites More sharing options...
simonr Posted February 7, 2007 Share Posted February 7, 2007 There is no simple or absolute answer to this because it depends on the direction the forses are applied to the frame. There is a lot of mileage in building a model out of straws, glued together. Try pushing in in different places to see how it resists movement. Design A in this instance will give the greatest resistance to being pushed sideways. It would benefit a lot from a vertical joining the tube above the radiator to the top of the chassis rail on each side to form a triangle. Mine looks like B, but with a diagonal from the corner to where the steering box bolts to the chassis, triangulating in two planes - and it has proven exceptionally strong! Si Quote Link to comment Share on other sites More sharing options...
Lewis Posted February 7, 2007 Author Share Posted February 7, 2007 Mark90 - Bob seamans, Justin deans and Rog's (898Kor) trucks have been inspiration for design A. DirtyDiesel built Bob Seamans wings and recommended design A for the 110 - which he will hopefully be building. Design B was borrowed blatantly stolen from SimonR's truck HFH, SimonR, do you mean like this or have I misunderstood? SimonR - have you had any issues with strength on your vehicle? And could you be so kind as to reinstate the photos of your build on sprocklegrommit, so that I may peruse them some more. Cheers Quote Link to comment Share on other sites More sharing options...
simonr Posted February 7, 2007 Share Posted February 7, 2007 SimonR - have you had any issues with strength on your vehicle? And could you be so kind as to reinstate the photos of your build on sprocklegrommit, so that I may peruse them some more. Cheers Not quite what I, at least was suggesting. This is what I meant: I would reinstate the photos on Sproklegrommet, however, all I have are the thumbnails. The masters were on a photo-hosting site, now no more! Guess many are gone for good! In the above design, the bar in front of the rad un-bolts to make engine removal a bit easier. The wings are entirely bolt-on (just in case one gets squashed!). In terms of strength, I have rolled the LR such that the weight of the vehicle was supported on the front corner of one wing and the rear of the cage. Plus, I have leaned on trees & rocks as hard as I can against the bars and nothing has moved! I decided not to tie it to the bumper as it is most likely to be bent and I didn't want it to bend the wing in turn. The wings finish above the bumper so it can fold underneath. Si Quote Link to comment Share on other sites More sharing options...
Lewis Posted February 7, 2007 Author Share Posted February 7, 2007 Thanks Si, I see what you mean now. Not attaching direct to the bumper sounds like a good idea Quote Link to comment Share on other sites More sharing options...
bishbosh Posted February 7, 2007 Share Posted February 7, 2007 Simon is a wise man - triangles are your way forward. Before I comment on the wing bars, can I first say that the first tube you add to your vehicle should be a diagonal brace in the roof of your cage. Front to back tubes are all well and good for fending off trees and end over end rolls, but you need triangles in all planes of your cage to get maximum strength. The screen bar is a good addition. Right, moving on…. Design A is the better option for strength. Triangulating to the bulkhead outrigger will improve your tube strength in the vertical plane (and improve buckling resistance from a head on hit) a bit but it does potentially move the weak point to the outrigger that would be loaded out of plane. (front to back) Personally I would rather repair a tubed wing than an outrigger… Tony is right that having the two sides connected means you risk damaging both sides in a bump, but on the other hand, having both sides joined means that you benefit from not damaging one side in a lesser bump because both sides resist the impact. Six and two threes in my opinion unless you can determine the magnitude and frequency of your bumps! Design B can be made as strong as A using Simon’s method. I think aesthetics really differentiates between the two designs. Try an envisage at least one triangle in each plane that the assembly can be loaded. Ideally, you would want a diagonal across the engine bay, but that might cause other issues!!! Next best is to take the loads diagonally down onto the chassis rails from the front corner of the wing to a point on the chassis rail around the steering box position (à la Simon R) My 2p. Quote Link to comment Share on other sites More sharing options...
Lewis Posted February 7, 2007 Author Share Posted February 7, 2007 Thanks Bish, no end of help The crayons have been out again, what do you all make of this? And have I missed anything? I'm not sure you can tell in the drawing but I've tried to keep the tubes to one peice where possible, mostly because I'm lazy but also because I cant weld very well and want to reduce the places where i'll make it look perform sh*t Quote Link to comment Share on other sites More sharing options...
bishbosh Posted February 7, 2007 Share Posted February 7, 2007 I personally wouldn't bother with the brace to the outrigger and from the outrigger to the chassis. You are better off bending the wings than the chassis. to improve the front to back stability take a diagonal from the top front corner of the wing diagonally back and down to the chassis This will also help prevent the front hoop of the cage getting out of plane forces on it. Quote Link to comment Share on other sites More sharing options...
simonr Posted February 7, 2007 Share Posted February 7, 2007 I'm not convinced about the bracing back to the cross member - but for a different reason. I built the model out of straws - almost exactly as you have it there. If you push hard enough on the front, the outrigger is so well held in place that the diagonal bar rotates around the end of the outrigger. This puts a shear load on the weld where the wing bar joins the front hoop. If this breaks - that tube enters the cab! If you loose that diagonal, the vertical of the front hoop bends instead, directing the wing bar downwards - but more importantly absorbing a lot of the impact energy. One of the most important things in a cage design IMHO is that when it is loaded in the way it is most likely to be, if a weld should break, the bits move away from you. The front will be good & strong. I moved the connection point of the diagonal down the the chassis down a bit from the apex of the corner to allow me to fit a standard headlight in the standard location. It also gives a void behind where the indicator and side light normally live. I appreciate the concern about relaying forces from one side to the other via the radiator bar. However, most of the impacts are going to be fairly light and this method reduces the likely hood of it moving. In an impact capable of moving both sides - you probably have more important things to worry about (like the cleaner unplugging your life support by mistake!). Si PS Cheers Bish - Cheque in post! Quote Link to comment Share on other sites More sharing options...
Lewis Posted February 7, 2007 Author Share Posted February 7, 2007 Okay, here goes Somefink like that? Thanks Quote Link to comment Share on other sites More sharing options...
bishbosh Posted February 7, 2007 Share Posted February 7, 2007 Looks about right to me. Quote Link to comment Share on other sites More sharing options...
SteveG Posted February 7, 2007 Share Posted February 7, 2007 Not based on any experience or knowledge , but it struck me when looking at Tony's and James bars that wouldn't it be easier/stronger to add outriiggers to front of chassis and bring bars down to this rather than bumper? Cheers Steve Quote Link to comment Share on other sites More sharing options...
white90 Posted February 7, 2007 Share Posted February 7, 2007 The bumper connection on James and my own is with small bolt the is meant to be a fuse if a big hit on the bumper occurs. but the connection also stops trees getting in between the bumper and wing, I've had this twice recently, damaging the wings both times. an outrigger on the front would need a fair amount of bracing this may foul the wheel on full lock, given there isn't much room in the engine bay thats why we chose behind the headlight for the support brace. Time will tell I guess. Quote Link to comment Share on other sites More sharing options...
LR90 Posted February 7, 2007 Share Posted February 7, 2007 Strength aside would it not be easier to fit side panel and eyebrow to design B rather than A (which in skeleton form I prefer)? Quote Link to comment Share on other sites More sharing options...
JST Posted February 7, 2007 Share Posted February 7, 2007 the theroy i had in my mind when making the ones for ours was that the current wings were only ali and got bent from brushing against trees, i intend to drive with the same due care(!) but now with the bars fitted the sides shoudl be protected, rather than drive smashing into things because i have the bars, i would also the bars bent rather than the chassis. just my thougths. as Tony says time will tell. Quote Link to comment Share on other sites More sharing options...
ciderman Posted February 7, 2007 Share Posted February 7, 2007 the theroy i had in my mind when making the ones for ours was that the current wings were only ali and got bent from brushing against trees, i intend to drive with the same due care(!) but now with the bars fitted the sides shoudl be protected, rather than drive smashing into things because i have the bars, i would also the bars bent rather than the chassis. just my thougths. as Tony says time will tell. This was the reason I did mine Just to take the brush damage away from the soft ali wings , Dont plan on knoking any trees over just yet , When I built mine I made them strong enough to cope and weak enough to eliminate knock on damage, A bit of a crumple zone if you like.It could make the difference of damaging your wings or getting thrown through the screen . Quote Link to comment Share on other sites More sharing options...
dollythelw Posted February 7, 2007 Share Posted February 7, 2007 When I built mine I made them strong enough to cope and weak enough to eliminate knock on damage, A bit of a crumple zone if you like.It could make the difference of damaging your wings or getting thrown through the screen . that makes more sense to me, it also saves weight the other would be why follow the standard wing profile? Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted February 8, 2007 Share Posted February 8, 2007 that makes more sense to me, it also saves weight The only problem i would have with lightwieght designs or those with a fuse. Is that in the event of a roll like lewis's You'd probably still be too heavily damaged to carry on the event, whereas if you take the sherman tank type of design you get to carry on regardless and the only trees you've got to watch out for are the 400 year old oaks Re-design A floats my boat the best. the other would be why follow the standard wing profile? Durrr.... so other luddites still accept them Quote Link to comment Share on other sites More sharing options...
dollythelw Posted February 8, 2007 Share Posted February 8, 2007 nice to see you've finally woken up cut the weight out of the top end and be less likely to roll in the first place? panzer boy.... Quote Link to comment Share on other sites More sharing options...
Lewis Posted February 8, 2007 Author Share Posted February 8, 2007 Strength aside would it not be easier to fit side panel and eyebrow to design B rather than A (which in skeleton form I prefer)? Yes it would, and if I was intending to keep the defender "look" then I would probably look at those a bit more, but changing the wing design isnt a concern for me, I care more for strength and longevity than aesthetics the theroy i had in my mind when making the ones for ours was that the current wings were only ali and got bent from brushing against trees, i intend to drive with the same due care(!) but now with the bars fitted the sides shoudl be protected, rather than drive smashing into things because i have the bars, i would also the bars bent rather than the chassis. just my thougths. as Tony says time will tell.JST I wouldnt say that I want to use them as i ramming tool, just that it would be nice to have a driveable car if it happens accidentally Plus keeping the car moving mid event after a roll like last sundays is a high priority for me with the 110, and fending off careless drivers on the streets of coventry in the 90 would be nice Re-design A floats my boat the best.DD Which one Dan, the first or second? Lewis Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted February 8, 2007 Share Posted February 8, 2007 Which one Dan, the first or second?Lewis The first one. Quote Link to comment Share on other sites More sharing options...
markwindsurf Posted February 8, 2007 Share Posted February 8, 2007 For my 2pence worth as an automotive structural designer, there are two options, a, do you wnat the tree bars to be absolutely solid and assume they are just tree bars, or b, are you looking for some deformation inan impact to prevent the full pulse from being passed onto yourself. Due to the nature I would assume 'a' is the direction you're aiming for in which case I would go with the first of your two sketches but would make use of some tubular front shock mounts which would attach to the two upper bars and down to the chassis, with the shock mounts suspended bellow the cross brace between the two top bars. If you wanted to go the whole hog and get a little indepth I could model the options in CATIA and run them through the analysis program to let you know which performs better. ( the more technical version of Simon's straws ) I would be tempted to look at the Raid Rally cars for their bracing ideas, Tomcat ( obviously my personal favorite ) and Wildcat pictures are all over the net, but if you can't find any I can get a wing on the Tomcat and take a picture. It is more simple than my suggestion and still incredibly robust, just the fibreglass which lets it down. Quote Link to comment Share on other sites More sharing options...
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