esxefi Posted November 8, 2016 Share Posted November 8, 2016 it'll definitely be heavier with timber doors,i take it the steel ones are beyond repair Link to comment Share on other sites More sharing options...
BiTurbo228 Posted November 9, 2016 Author Share Posted November 9, 2016 Well, I responded to an ad that said 'carbon fibre doors'. Imagine my surprise when a load of pine turned up Link to comment Share on other sites More sharing options...
BiTurbo228 Posted November 9, 2016 Author Share Posted November 9, 2016 Denizen no.2 has taken roost Really good to get it out of the weather. It’d just have disintegrated outside, and then I’d be no better than the other loonies that horde cars and leave them to rot! Link to comment Share on other sites More sharing options...
BiTurbo228 Posted November 21, 2016 Author Share Posted November 21, 2016 Well, thanks to the weather progress has been glacial, but there has been progress nonetheless! This is a freshly repaired leading edge of my hardtop. As with any big panel with complex pressed curves it's warped a little, but some persuasion with a hammer and a bit of forethought should minimise the amount of filler it will need. I’ve also finished the cladding on most of my parts shed just needs some doors in place and i can finish it off! Link to comment Share on other sites More sharing options...
BiTurbo228 Posted December 1, 2016 Author Share Posted December 1, 2016 Onto the spit with the Spit Finished the majority of the welding on the roof (or at least enough for it to keep its strength when lifted). Now I’ll box in the chassis to the floorpan, hopefully giving it quite a bit of structural rigidity in the process certainly feels very solid (you could lean on the windscreen surround and it'd bend before!) Patched up the sides which looked good on the outside but were very crusty behind the seams. Lastly, patched up the little sections under the rear quarter windows and boxed it into the bodyshell Link to comment Share on other sites More sharing options...
BiTurbo228 Posted December 10, 2016 Author Share Posted December 10, 2016 So, this is why my Spitfire is called 'Patchwork'... Finished boxing in one half of the body to the chassis. The two floor panels are my repairs, all the stuff at the top is one of the dozen or so previous owners. From my (incredibly) rough maths, this should increase chassis stiffness to ~140% of its original stiffness, 10% more than just solid-mounting might even be more as I did all of that before I welded the hardtop to it! Link to comment Share on other sites More sharing options...
BiTurbo228 Posted March 6, 2017 Author Share Posted March 6, 2017 Long-time no post, but I am still alive! Crappy weather and other bits and pieces not really worthy of a post means it’s only come along at a slow pace over the winter. Still, boxed in the other half of the chassis today just a couple of little corners and bits and pieces to weld then it’s officially a complete unibody Spitfire Link to comment Share on other sites More sharing options...
BiTurbo228 Posted April 3, 2017 Author Share Posted April 3, 2017 Just finished beefing up the body mounting bracket so I can brace the suspension tower against it without having a crash result in a weld-hardedned spar of steel skewering my legs Bracket: First step is to chip off all of the underseal gunk and make sure the steel behind it is solid. So far so good. Then onto some Binky-esque CAD (Cardboard Aided Design) templates. First plate made from 3mm steel was easy enough. Simple cut, bend roughly into shape, tack one end, beat with a hammer until it’s the shape it needs to be and then weld in fully. The next one required a cup of tea and some thinking time. I could bend it roughly to shape with some muscle and a vice, but it wasn’t quite as square as I’d hoped. Luckily, a piece of spare box section I had seemed the right shape so I used the vice to press it into a better shape. A bit more hammering and a bit more pressing and voila! Very neat Drill some big holes for some beefy plug-welds and spray with some weld-through primer in an attempt to rust-protect the back slightly... ...and tack in place. This as proof that every now and again I can lay down a weld that looks bang-on More primer and a new plate over the top. Hopefully that should be a proper strong-point for the tubing to mount to, and the double-thickness of 3mm steel welded to the chassis extension should prevent it tearing off there and pivoting backwards. I’ve done the other side in an identical manner as well and one more job ticked off the list Welding-wise, I’ve got one more plate tying the hardtop to the roll hoop, welding the roll hoop feet fully to the bodyshell, re-locating the rear suspension mounts inboard of the chassis for better geometry and ground clearance, and the brace structure explained at the start of this post. Then I might be able to do something that’s not welding! God forbid! Link to comment Share on other sites More sharing options...
BiTurbo228 Posted April 10, 2017 Author Share Posted April 10, 2017 It's the Spitfire Suspension-o-matic Grommit! After a solid day’s worth of googling chassis diagrams, measuring, rusty maths and general head-scratching I am done! In order to work out the best place to mount a custom lower wishbone to get a decent camber curve as the suspension moves this is a to-scale plan view of a rotoflex GT6’s rear suspension The idea’s cribbed shamelessly from Marcus, but with a few improvements based on his experience. Primarily, he used another piece of wood for the upper link, but as the upper link on a Spitfire is a leaf spring it bends as it arcs upwards, pulling in the top of the wheel more than it otherwise would do with a solid wishbone. Worked positively for Marcus in the end, but I thought I'd see if I could account for it I contemplated working out the maths to calculate the curve and quickly decided that my decade-old education is thoroughly inadequate for that sort of complication. So, I thought I’d make a leaf using some thin-wall PVC oval tube I found lying around works rather well! First impressions are that the camber change seems quite large (although I’m yet to work out what the actual suspension travel is yet). Next is that surprisingly it’s in the right direction. From a brief look at suspension location, you’d know that having a much shorter lower link will cause positive camber under compression as it describes a tighter arc, pulling the bottom of the wheel inwards more. That’s counteracted here by mounting it at an angle, meaning that it pushes the bottom of the wheel out under compression, resulting in negative camber. The trade-off for this is increased positive camber under droop. Now the fun bit the image below is the main chassis rail (the red box) and 4 potential new wishbone locations (the F, R and M are how far the chassis drops down from the main plane at the rear) Using some new scraps of wood, I can do this! Much, much reduced camber change for the same suspension travel Next up is to read up a load and do some more head scratching about what the camber curve should be, and experiment to try and find a location that fits that best. Then, I’ve got some more head-scratching to do to make sure that my chosen location has an acceptable roll centre. Then then, I’ve got a couple of popular aftermarket wishbone locations (and a few homebrews) to test out as well. Then then then, I get to do it all over again with a new diagram overlaid in blue to simulate a 3/4" lowering block under the spring. Then then then then, I can actually make a jig for the brackets, make the brackets and weld them in place. Then then then then then, I’ve got a cunning plan for making adjustable lower links... Not much to do then Edit: I'll post up all the dimensions I used to make this when it's not half 1 in the morning! Link to comment Share on other sites More sharing options...
BiTurbo228 Posted April 10, 2017 Author Share Posted April 10, 2017 (edited) As promised dimensions! Some will be repeated in different areas, but just making sure I've got everything down. I'll also see if I can make a drawing with dimensions as that might be easier to reproduce ----------------------------------------------------------------------------------------------- Upper link Rotoflex leaf spring (as fitted): 522.5mm Rotoflex leaf spring (unfitted so beyond max droop really): 505.0mm Top vertical link eye to hub face (not the actual hub itself, but the outer face of the VL): 94.361mm Distance from chassis centreline to outer spring bolt (the point at which the eye would be if the leaf spring was a standard link): 38.1mm Total upper link arm length fitted (leaf length minus distance to spring bolt): 484.4mm Total upper link arm length beyond full droop (by an unknown amount as I can't find what the suspension travel is): 466.9mm Total distance from centreline to outer VL face: 616.861mm Lower link Centreline to outer face of chassis: 285mm Chassis to rotoflex bracket eye (horizontal, using Canley's figure of 315.7mm): 29.3mm Chassis to rotoflex bracket eye (vertical): Need to measure this as I described an arc until it met 29.3mm away from the chassis while the VL is vertical Rotoflex wishbone (straight): 236.474mm Rotoflex wishbone (as fitted on a slight incline to achieve the factory 0 degrees camber): 227.25mm Top vertical link eye to hub face: 75.311mm Total lower link length fitted (just the rotoflex wishbone): 227.25mm Vertical link Top eye to lower eye (vertical): 233.362mm Top eye to lower eye (horizontal): 19.05mm Top eye to VL face (horizontal): 94.361mm Lower eye to VL face (horizontal): 75.311mm Shock mount hole to lower eye (horizontal): 34.138mm Shock mount hole to lower eye (vertical): 45mm (edited for accuracy) Chassis Chassis outer face from centreline (horizontal): 285mm Chassis width (inc. flanges): 70mm Chassis width (exc. flanges): 50mm Chassis height: 82mm Chassis distance below datum line (the technical drawings use a datum line above the height of the main chassis rails, but it makes it much easier if you use the upper face of the chassis on the main plane as a datum point for measuring from. All my measurements below are from that level): 28.7mm Spring mount above chassis: 109.72mm Lowest point of chassis where it bends down to loop under the driveshaft: I've got this at home but not with me at the moment. VL top eye above chassis (assuming leaf is level when fitted): 109.72mm Shock eye above chassis: 154.2mm Shock eye from centreline (horizontal): 374.6mm Front diff mount below top of chassis: 5mm Rear diff mount above top of chassis: Forgot to write this one down! Shock location Chassis shock eye above chassis (vertical): 154.2mm Chassis shock eye from centreline (horizontal): 374.6mm VL shock mount hole to lower eye (horizontal): 34.138mm VL shock mount hole to lower eye (vertical): 45mm (edited for accuracy) ----------------------------------------------------------------------------------------------- I need to try and find dimensions for the outer face of the hub as fitted to the VL, as thinking about it that extra length will affect the camber change, and actually get some solid data on the shocks... Edited April 11, 2017 by BiTurbo228 Link to comment Share on other sites More sharing options...
Nick Jones Posted April 10, 2017 Share Posted April 10, 2017 I like that....... I like it alot. You do need the damper dimensions and also to consider how you will mount the damper (direct to swing axle chassis bracket, using chassis bracket extensions or copying the GT6 Mk2 mounts on the wheel tubs). The reason I say this is that it sets the range of travel and camber variations are most extreme at the ends of travel. The hub dimensions won't affect the camber change...... Nick Link to comment Share on other sites More sharing options...
BiTurbo228 Posted April 10, 2017 Author Share Posted April 10, 2017 Thanks! I've managed to measure my vertical link to get the damper locations (it's 45mm up from the lowest hole, not 40mm), and got an email from Rimmers confirming the shocks travel from 240-300mm. I thought that would be way too long for my Spitfire suspension bracket, but it actually sits quite nicely at 268.5mm with the spring dead horizontal. Using that, I've measured that there's 43mm of bump and 50mm of droop at the hub face, and marked it on my model (including marks for inches of suspension travel for when I test stuff). Oh, and the hub is 13mm from the face of the VL, and the brake drum is 6mm thick, meaning I've extended the vertical link (and 0 degree line) by 19mm. It has affected the camber, but only imperceptibly. If I stick my metre rule along the VL face it's about 1mm away from the line at the far end so I'm not worried. I've also drilled a load of holes for other popular wishbone mount locations. Red is standard spring fitment, blue is with a 3/4" lowering block and green is with a 1" lowering block. 'Racing' is the racing bracket (25mm down, 5mm out) and 'Roto 2' is the lowest bracket hole in the Canley's rotoflex bracket. This is the point where I realised I don't own a protractor :S drat. Off to the shops tomorrow! Link to comment Share on other sites More sharing options...
BiTurbo228 Posted April 10, 2017 Author Share Posted April 10, 2017 Wish I could work out how to edit posts... Here's the pic of the extra wishbone locations Link to comment Share on other sites More sharing options...
BiTurbo228 Posted April 10, 2017 Author Share Posted April 10, 2017 Oh, and here are the new and improved dimensions: Upper link Rotoflex leaf spring (as fitted): 522.5mm Rotoflex leaf spring (unfitted so beyond max droop really): 505.0mm Top vertical link eye to hub face (not the actual hub itself, but the outer face of the VL): 94.361mm Distance from chassis centreline to outer spring bolt (the point at which the eye would be if the leaf spring was a standard link): 38.1mm Total upper link arm length fitted (leaf length minus distance to spring bolt): 484.4mm Total upper link arm length beyond full droop (by an unknown amount as I can't find what the suspension travel is): 466.9mm Total distance from centreline to outer VL face: 616.861mm Total distance from centreline to outer hub face: 635.861mm Lower link Centreline to outer face of chassis: 285mm Chassis to rotoflex bracket eye (horizontal, using Canley's figure of 315.7mm): 29.3mm Chassis to rotoflex bracket eye (vertical): Need to measure this as I described an arc until it met 29.3mm away from the chassis while the VL is vertical Rotoflex wishbone (straight): 236.474mm Rotoflex wishbone (as fitted on a slight incline to achieve the factory 0 degrees camber): 227.25mm Top vertical link eye to hub face: 75.311mm Total lower link length fitted (just the rotoflex wishbone): 227.25mm Vertical link Top eye to lower eye (vertical): 233.362mm Top eye to lower eye (horizontal): 19.05mm Top eye to VL face (horizontal): 94.361mm Lower eye to VL face (horizontal): 75.311mm Shock mount hole to lower eye (horizontal): 34.138mm Shock mount hole to lower eye (vertical): 45mm Hub face from VL face: 13mm Brake drum thickness: 6mm Chassis Chassis outer face from centreline (horizontal): 285mm Chassis width (inc. flanges): 70mm Chassis width (exc. flanges): 50mm Chassis height: 82mm Chassis distance below datum line (the technical drawings use a datum line above the height of the main chassis rails, but it makes it much easier if you use the upper face of the chassis on the main plane as a datum point for measuring from. All my measurements below are from that level): 28.7mm Spring mount above chassis: 109.72mm Lowest point of chassis where it bends down to loop under the driveshaft: I've got this at home but not with me at the moment. VL top eye above chassis (assuming leaf is level when fitted): 109.72mm Shock eye above chassis: 154.2mm Shock eye from centreline (horizontal): 374.6mm Front diff mount below top of chassis: 5mm Rear diff mount above top of chassis: Forgot to write this one down! Shock location Chassis shock eye above chassis (vertical): 154.2mm Chassis shock eye from centreline (horizontal): 374.6mm VL shock mount hole to lower eye (horizontal): 34.138mm VL shock mount hole to lower eye (vertical): 45mm Shock fitted length as per above distances: 268.5mm Shock full bump: 304mm Shock full droop: 240mm Suspension bump travel at hub face: 43mm Suspension droop travel at hub face: 50mm Link to comment Share on other sites More sharing options...
Nick Jones Posted April 10, 2017 Share Posted April 10, 2017 Edit down the bottom of the post box to the left of Multiquote etc. Grey and faint until you hover over it but, as an advanced member, it should "light up" for you when your mouse pointer passes over it. Nick Link to comment Share on other sites More sharing options...
BiTurbo228 Posted April 10, 2017 Author Share Posted April 10, 2017 Huh, I've only got the option to 'report' my own post :S that's greyed out and lights up, but I've just checked and there's nothing else hidden there... Link to comment Share on other sites More sharing options...
oldtuckunder Posted April 10, 2017 Share Posted April 10, 2017 Likewise, I think you have to be on Nick's pay grade to edit Alan Link to comment Share on other sites More sharing options...
daisymoose Posted April 10, 2017 Share Posted April 10, 2017 Phoey - too slow!!!! Can confirm from a set of v links I have(one built up still - the other stripped) that your earlier missing dimensions are the same as I have measured on my set - give or take a few thou Drive flange to spring eye bolt ctr = 106.5 Vlink face to spring eye bolt ctr. = 94.5 Drive flange to btm arm bolt car. = 87.35 Also Watching with great interest!!!!!! I've spent hours drawing this on CAD and farting around with pick up points till I've tied myself in knots hopefully you are about to confirm that I'm not as daft as I think I am Interesting project - good luck Dave Link to comment Share on other sites More sharing options...
GT6MK3 Posted April 11, 2017 Share Posted April 11, 2017 Editing is available to "Supporter" members. It's a one off 25 dollar donation that reduces the amount I reach my incredibly short arms into my pocket to pay the hosting and software update costs. We run Sideways on the smell of a Triumph style rag, but every bit helps. http://sideways-technologies.co.uk/forums/index.php/subscriptions/ Link to comment Share on other sites More sharing options...
BiTurbo228 Posted April 11, 2017 Author Share Posted April 11, 2017 Glad the dimensions actually seem to fit real life! I know the one for the rotoflex brackets in the workshop manuals is out by 20mm so it's good to confirm with actual measuring. Subscription done and done Link to comment Share on other sites More sharing options...
BiTurbo228 Posted April 18, 2017 Author Share Posted April 18, 2017 Well, I've finally got a day of testing in over easter here are some choice results: Now if only I knew what a good camber curve looked like... Tested the stock setup, a number of aftermarket options, and a couple of custom locations. Came to some interesting conclusions. For instance, the much-maligned stock setup actually seems to have quite a good camber setup for cornering (for a car with a decent amount of roll), but would likely suffer under braking or acceleration due to the sharp positive camber at full droop. The aftermarket lowering blocks (represented by the -13/4" and -1" versions) reduce the high positive camber on droop, but replace it with negative camber so would likely be more stable under braking, but less grip in corners from the inside wheel, unless the added 0.5 degree negative camber on the outside wheel offsets that. The lowest hole on the Canleys rotoflex brackets also reduces the sharpness of positive camber on droop, but replaces it all with negative camber, likely having a similar effect to lowering the car but at standard ride height. When you start lowering that, things start getting really weird. -3/4" is pretty much zero camber change, aside from full droop. -1" is all over the place. Racing -1" is a location found previously to produce zero camber change over the whole of the suspension travel, so it’s reassuring that the same result is found using my model The suspension design pioneered by Marcus (Under) produces very slight camber change (less than a degree either way), and in the right direction. Would work very nicely on a car with very little roll. That is provided I've got them in the right place as I did guess roughly where he had them from the pics and may have got it wrong. 3 choice picks of my dozen or so experimental locations are interesting too. I like option 2 and 9, although again would probably need to have very little roll if my understanding of optimal camber is correct. Option 4 is even more interesting for racing as you can have dead-flat wheels on droop meaning nice straight braking, but still have a little negative camber on corners. Now I just have to take the favourites and work out where the roll centres are... Link to comment Share on other sites More sharing options...
BiTurbo228 Posted April 18, 2017 Author Share Posted April 18, 2017 Well, after musing on this at work today (and also thinking about sidewall flex on initial cornering), I decided to try a few setups with just a smidge of initial negative camber. No.2 with -1deg of camber at rest seemed pretty damn promising. From full bump to full droop it goes -2.5, -2(full bump), -1.5, -1(rest), -0.25, 1(full droop). That would mean that you’d end up with a little more negative on the outside wheel when cornering, damn near level when braking, and still a little positive for inside wheel grip when cornering, but not quite as positive and previously under really hard braking. Seems rather promising Link to comment Share on other sites More sharing options...
Nick Jones Posted April 18, 2017 Share Posted April 18, 2017 You are certainly putting plenty of effort in....... and seem to be getting some good results. Not sure I'm understanding the description of the pivot point locations though........ my little monkey brain needs pictures - simple stick-man sketches sufficient! Nick Link to comment Share on other sites More sharing options...
BiTurbo228 Posted April 20, 2017 Author Share Posted April 20, 2017 Thanks! Yeah it's very interesting trying to fathom out what does what when you're moving stuff around. There's too much interplay between length, height and angle for it to be straight forward so lots of testing. I've found it's fantastically tricky to explain anything more than very simple geometry using words so I think it's all of our monkey brains, not just yours I'll scribble something out to try and explain Link to comment Share on other sites More sharing options...
BiTurbo228 Posted May 3, 2017 Author Share Posted May 3, 2017 Tedium at work today finally tipped me over to having a go at modelling my chosen suspension design online and I must say I'm pretty pleased with the results For reference, the stock Rotoflex wishbone brackets are 99.3mm outboard and a hitherto unmeasured distance higher (I'll measure that soon!). From all this mucking about I've found that the roll centres don't move a great deal. In bump/droop they move by a maximum of 105mm vertically each way at full travel, and in roll they travel 259mm at 5 degrees of body roll (25mm of that vertical) which I gather is not bad More importantly, the camber curves of this mirror my wooden model closely enough in bump and droop for me to use it for camber change in roll relatively accurately. Again, that's quite good. Up to 2.5 degrees of roll the negative camber of the compressed wheel slightly exceeds the degree of body roll. At 2.5 degrees it matches it, and then starts to drop off slightly (at 3 degrees of roll the camber gain is -2.8 degrees). From what I imagine that would result in good grip up until the body starts to approach 2.5 degrees. At that point, it'll either break away gradually or snap oversteer as it decambers. I can't quite figure that one out in the old headphysics model just yet... Have a muck about with the model if you like http://racingasp.com/1fhre8zt Link to comment Share on other sites More sharing options...
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