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What's your timeline to completion? Neat to see all the work and thought put into this.
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Apr 3, 2021 14:25
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| # ? May 1, 2024 14:56 |
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Suburban Dad posted:What's your timeline to completion? Neat to see all the work and thought put into this. Honestly, it's been good for my mental health not to think in timelines other than kinda vaguely; I've had enough exposure to arbitrary deadlines in my professional career. What I do is give myself a series of shiny objects. Like, right now the physical side is "get steel for tube notcher and chassis" which is waiting on the truck to be fixed... the prepreg NACA duct stuff is a wholly separate "thing to learn capabilities with", the wheel scanning was "enable some design stuff that's figured out in concept and needed finalizing" final bodywork design requires me to learn some stuff in CAD to do it right (I'm not great at surfacing) and the next "figure this out, I don't have this planned out" sorta stuff is more detailed mounts and ducting and stuff. So when I have time I just poke at whatever I feel like, on average of an hour or three a day. I think a realistic goal is to get the chassis structure knocked out before fall, and stuff relating to bodywork started around then too, but it's not very concrete; stuff comes up both in a 2020 sense and a personal life sense. I have a perfectly functional race car that I can get on track with once all the stuff for that works out too; this whole tube chassis project is kinda "build what may be the last race car I own" so I want to not stick myself with bad decisions to the greatest extent practical.
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Apr 3, 2021 14:46
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Fair enough. Seems very ambitious but fun to learn about a billion different things.
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Apr 3, 2021 14:50
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Well, that's the thing - if I wanted a finished product I could just save up and buy it. But I like designing and building stuff; so it's an ambitious thing I can design, build and then race? Perfection.
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Apr 3, 2021 15:07
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Phew. Best of luck, that's hella ambitious. Bagging something as large as a fender in situ is not easy. I swore off carbon kevlar for even beer money after college. (And vowed to never own a boat made out of it.)
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Apr 4, 2021 01:12
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 From the last thread... this was a few cars ago. All the visible bodywork in front of the doors/windshield was glass in borrowed molds, albeit wet layup. The big problem was the borrowed molds part, well and that they were on a unibody car. Well that and I didn't like that style as much but that's a separate issue. The molds were done (by a friend) with chopped strand mat over gelcoat and had the flanges riveted on, so every used they had to be drilled apart - all sorts of little pains like that. That's my benchmark though; that's cumbersome but acceptable, could probably turn out new body panel sets in a good weekend. I figure with better designed, more rigid molds that bolt together with alignment features and with prepreg and stuff it could be more pleasant... but "unpleasant" is still acceptable.
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Apr 4, 2021 02:17
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Makes sense. I guess the question is will you need enough panels that the extra work upfront pays off down the road.
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Apr 6, 2021 02:11
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I figure I've wanted to build a car like this for 20-some years, so my intent is to build it and then run it with mild evolutions until I can't - ideally due to old age. But basically the whole car is a long term exercise in "OK, what is every step to make sure I can keep this running on the race track?"
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Apr 6, 2021 02:49
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 Working on bodywork... sort of what I have in mind for front fenders.
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Apr 14, 2021 22:50
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Interesting!
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Apr 14, 2021 23:38
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If you're doing surface work in solidworks make sure to take advantage of the zebra tool or export and import into an actual surfacing program, their representation of surfaces is poor enough it will hide a lot of screwyness with wavy or rippled surfaces you won't see until you make molds, it's bitten me before.
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Apr 14, 2021 23:43
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I don't know any "real surfacing tools" so ... oh well. It's a little ripple-ey but I was anticipating hand cleanup of the molds and stuff anyway; I'm sure it'll be race-car fine.
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Apr 15, 2021 00:24
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Well, on the 7th or so retry since I kept having bad surfaces... realize that duh, I don't actually give a poo poo if it's perfectly accurate to the stock contours, so current redo is going a bunch of surface sweeps. Still a pain in the butt but I suspect at least part of that is that I last played with surfacing stuff like, a few years ago.
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Apr 16, 2021 01:26
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So, upon thinking about it... it's a race car, it'll have decals and stuff on it, and so on. I don't give a poo poo if the bodywork is accurate to the thou, just needs to look right. Zebra display is nice and smooth too. Loses little details here and there but, hard meh, racecar.
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Apr 17, 2021 22:26
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Laying out more bodywork; did the doors because they're relatively easy plus provide perspective for some other stuff Borla makes some rotary-specific mufflers - hey look, two of them fit! I may just fab my own to make sure it drat well lasts but now have a good idea how much space to play with. Mufflers will probably be inside a box lined with heat shielding, fed with air from the wheel well at the front; should help control cockpit temperatures.  A bit of perspective on how far inboard the driver is pushed - door skin is at stock width, driver model is roughly scaled to, well, me.
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Apr 22, 2021 23:47
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mekilljoydammit posted:
Love the smile.  This is looking great
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Apr 23, 2021 03:38
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Working on laying out interior paneling a bit, will post pics when that's farther along, maybe Sunday. In the mean time, just decided that most of the in-plane tube miters are pretty simple and I'm feeling antsy. So found a place that may deliver steel and thing I'm going to put in an order Monday. Definitely going to do the CNC notcher at some point but I don't need it to start.
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Apr 24, 2021 03:20
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  Well hello... sometimes the price is right. Pair of Performance Friction ZR34 front calipers. Monoblock radial mount intended for circle track but they get used everywhere because they great value. Especially with what I paid.
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Apr 28, 2021 19:17
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I've found what I consider to be some pretty cheap pricing on Amazon and parts houses for the factory GM Brembos used on various Cadillac Vs and Camaro/Corvettes. Amazon keeps showing me suggestions for V 4-piston calipers @ about $125, which doesn't seem terrible (though I've not priced out Brembos direct for some time.) edit: also, if you're not aware, https://www.racingjunk.com/ seems to be a useful site for used, uh, racing junk. Darchangel fucked around with this message at 20:58 on Apr 28, 2021 |
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Apr 28, 2021 20:46
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These honestly weren't a whole hell of a lot more than that. I'm obviously going to replace seals though. The big thing with the caliper selection is that I'm at a particular niche... the OEM style Brembos tend to be optimized for 13-15 inch rotors or so and bigger wheels. These are optimized for 15 inch wheels with 11.75" rotors; they're intended for circle track but hey, it just turns out I have the same sort of constraints! They also use thicker pads than most OEM calipers, don't use dust boots (which tend to melt) and are monoblock instead of bolted together. Brembo makes stuff in this market space too but boy howdy do they cost. These were intended for late model stock cars and so are deliberately cost contained.
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Apr 28, 2021 21:02
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Interesting, what are the piston sizes on them?
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Apr 28, 2021 21:23
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Stock car/dirt track stuff is a handy resource. Particularly for my '70 Cutlass. GM A-body use to be all over budget oval racing, and a lot of the newer stuff is stilled based on those parts.
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Apr 28, 2021 21:36
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BlackMK4 posted:Interesting, what are the piston sizes on them? These ones are 41/44mm; there's a 25.5/29mm version, and PNs for left and right leading or trailing for both piston configs. They're solely for 1.25" wide rotors and are about Wilwood Superlite size. Not so obvious neat feature is that they use PFC's fancy insulated piston noses - two piece piston with a polyimide insulator between them to slow heat transfer into the brake fluid.
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Apr 28, 2021 22:15
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I know nothing about laying up fiberglass but could you do it with the macro metal flake like on bass boats and dune buggies? Good job on all the time and effort you're putting into this.
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Apr 28, 2021 22:22
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mekilljoydammit posted:These ones are 41/44mm; there's a 25.5/29mm version, and PNs for left and right leading or trailing for both piston configs. They're solely for 1.25" wide rotors and are about Wilwood Superlite size. Not so obvious neat feature is that they use PFC's fancy insulated piston noses - two piece piston with a polyimide insulator between them to slow heat transfer into the brake fluid. Now that is interesting, do they also share the same mounting configuration as the Superlite?
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Apr 28, 2021 23:24
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BlackMK4 posted:Now that is interesting, do they also share the same mounting configuration as the Superlite? The radial to lug mount adapters on mine are literally Wilwood parts if you look closely enough.
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Apr 28, 2021 23:32
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wankel13b posted:I know nothing about laying up fiberglass but could you do it with the macro metal flake like on bass boats and dune buggies? Oh yeah... unfortunately all the metal flake systems are polyester as opposed to epoxy, much less prepreg... so I could if I wanted to do heavier, floppier, harder to work with bodywork, but not with prepreg carbon fiber. Which is kind of a shame. I have a general paint scheme in mind with a few stripes of color on top of bare carbon in places.... metal flake would have been hilarious.
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Apr 29, 2021 02:21
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You can add metal flake to clear coat. CF still needs UV protection, right.
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Apr 29, 2021 04:15
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Aaaaand, last bits for the welder outlet are here, and now I have a first batch of steel ordered. Excited as hell!
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May 7, 2021 21:31
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Nice! Starting with basic frame stuff?
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May 7, 2021 23:10
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Yeah, god knows there's plenty of that to do.
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May 7, 2021 23:12
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Almost welding time, that's when it gets real  Look forward to this starting to come together. How many CAD versions and revisions are you up to now?
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May 8, 2021 10:41
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I'm up to Mk14 but most of the major details were sorted out by Mk8 and it just fell down to trying minor variations to try to optimize stiffness per weight, and the latest Mk is just trying a rear suspension variant. I just have wanted to be able to put a signpost down each time I had a new idea in case it didn't work out.
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May 8, 2021 14:32
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 And now the fun begins! (well soon, I still need a couple things to finish wiring my welder circuit)
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May 10, 2021 21:45
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 This is going to be very fun to watch you assemble.
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May 12, 2021 02:43
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I'll take update photos whenever I remember to; I still have a few more days of "preparing the workspace"
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May 12, 2021 03:16
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 Maybe not the sexiest thing, but got cross-tubes for the chassis table cut out. Just need to get some stick electrodes and some grinding consumables and will have that done, nice and flat and sturdy.
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May 15, 2021 23:04
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I wish I had enough garage for a frame table. Looking good so far. Got some kind of datum baked in to measure from?
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May 16, 2021 00:07
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Sort of! The tubes are going to be at 2' spacing as close to dead nuts as practical, and I'm going to paint/scribe a centerline afterwards... most of the actual chassis squaring within the plane is going to be to various datums that I can measure on their own, if that makes any sense. I'll take pics of setup stuff as I go - I think some people might appreciate ideas I have on how to do this stuff accurately.
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May 16, 2021 00:29
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Yeah that makes sense, and very much intereted in how you'll do it. What I'm working on now is a best path to track car based on time, budget, and skill, but I'd love to make something that's a truly dedicated race car in the future.
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May 16, 2021 01:30
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