This is a good time to start a new diary, as the project has begun!
As parts are purchased they are added to the Part Sources list. This puts all purchases in one place instead of burying them in endless diaries - like I did with Kimini.
We'll see how much work I get done on the table tomorrow. Over the last two and a half years, Kimini's windshield has slid downward about 1/8". This isn't a big surprise, since glass gets hot in the sun and silicon sealant (and windshield adhesive) gets soft. Before putting her into storage I think it would be wise to add some non-metallic (so it doesn't crack the glass) "feet" to the bottom of the lower windscreen clamps, giving the glass a little shelf to rest on. It'll be done now because it may get warm enough in storage that the glass moves further, like a glacier slowly heading for the sea...
Designing the chassis table. I thought 5' x 10' sheets of MDF existed but apparently not (I'm not sure where I got the idea.) I'll have to make due, using 4' x 8' sheets to create a 5' x 10' work surface. A table that large will support the entire chassis, rather than having it hang over the edges - like a huge guy on a scooter.
Kimini's storage space is all set so that'll happen this weekend. On Sunday, work on the chassis table will begin and I'll make sure to take lots of pictures - the first ones for the book! Things are starting to get exciting, once again.
In other news, in early October of last year I sent a book to a guy in Canada. Several weeks passed and it hadn't arrived so I sent another free of charge. Got a note from him today that the first book arrived - seven and a half months late! Guess they aren't kidding about Customs being backed up with Canadians buying lots of U.S. goods due to the low dollar.
Work on the manuscript continues. This quiet time is perfect for building a strong foundation for the construction sections that are soon to follow.
I got a note from someone, frustrated (in a good way) that things aren't moving along faster. That'll happen at the end of the month where, after the big Mini Meet West event, Kimini will be put into storage. It's near by and convenient so I can still drive it at least once a month to keep it in running order. Anyhow, this frees up the garage and you'll start seeing things happen. Not sure what will be first, the chassis table or the wood mockup. The mockup will happen either way, it's just a question of whether I want it elevated or not.
Ordered a "car pocket", also known as a car jacket. It's essentially a giant zip-lock bag that you drive your car into so that during storage, it keeps dust, water, bugs, and mice out of the car. Between that and a good car cover, Kimini's going into storage until she sells.
The Midlana site has been moved to its own domain, www.midlana.com so it can now be accessed directly. This officially moves Midlana out from under the Kimini umbrella in order to improve Web visibility. I also added a "Misc" link to the front page, an effort to keep non-car stuff (and rants) separate from the designing and building. If you're bored and want to see what's going on in my life outside of cars, there you go.
Working on the manuscript. It's on a roll and practically writing itself. One huge advantage of writing it in parallel with the project is that things that would otherwise be forgotten are not. As for Kimini, I've decided how and where to store her so now it's a matter of getting the location prepared.
Received the Wavetrac LSD in perfect condition. I'll try to deliver it and the transmission to the tranny guy this weekend. I've been told that it's "easy" to install... eh, could be, but I rather pay to know it's done right.
Sorry for the lack of updates but there just isn't much to report. Spending time on the book manuscript, updating it with my latest thoughts and bringing it up to date to keep it in-line with my progress, such as it is. The idea is that when the car's done, the book will be, too.
Assuming Kimini doesn't sell soon she'll be put into storage. I refuse to give her away at too low a price, but my sense of urgency to get going with Midlana is reaching the breaking point.
Bought a WaveTrac (Quaife LSD successor), a key requirement of the project. It's a cool assembly, both a gear-type and clutch-type LSD - theoretically the best of both worlds. From people who do a lot of trackday events, the word is that clutch-type LSDs are good for nearly two seconds a lap, which is a lot of time. This is apparently due to the clutch-type diff continuing to work when one wheel is in the air, like when driving over berms, while the Quaife goes open in those conditions. I'm taking a bit of a risk getting it now since I've yet to hear how they do on-track, but I'm expecting good things. I'd like to get the tranny inspected and have it installed at the same time, just to get that task out of the way. That way it's considered a ready-to-go item that I don't have to worry about afterwards.
The engine, however, is a self-imposed bigger deal. It'll need to come apart, inspected, then rebuilt for turbocharging service, though this can wait until later. On the other hand, if for some reason I can't start on the chassis soon, it's tempting to dig into the engine, that way at least some progress is happening. The downside is that an unused engine can have rust form on the cylinder walls and the valve springs can take a set. We'll see... I can aways turn it over by hand every few weeks.
I had a professional Mechanical Engineer look over Midlana's CAD drawings, who gave it a thumbs up. He made a couple of good observations which I'll incorporate. He shares my irritation with the SCCA rule that allows using 1.375" x 0.080" rollcage tubing - which can neither be found nor be able to locate anyone to mandrel-bend it!
A generous reader, Matt, volunteered to run my CAD chassis through FEA (finite element analysis). The chassis has already changed since last week and will probably change more, but knowing its approximate stiffness is helpful. The center tunnel has already changed, too, now a 4" wide x 12" tall affair with about 5000 ft-lbs torsional rigidity.
The pictures are of last Saturday's Irvine car "thing." Notables were the 1970 Porsche 917 and that crazy Nash Metropolitan with its big-ass engine. It was like a big leaf blower when he drove in, the bottom-exit pipes blowing dust everywhere. With the idle surging up and down it made simply driving through the lot a chore. Amazing that he drives it on the street! Of course I suppose he could say the same of me. On the way out I couldn't help but get a shot of Kimini next to it.
Not related to the Nash - really - I verified that Kimini's top speed is 127mph, gear-limited. It was still accelerating pretty well so I'm guessing perhaps 135mph aero-limited, which means the drag coefficient is lower than expected. I'm happy. (Early Saturday mornings the freeway is pretty empty; I didn't pass anyone during this test and endangered no one but myself.)
A surprising number of people wrote to say that I made the car too short in wheelbase. I'm not sure where that comes from since I didn't supply any numbers. I think it's due to the wide track, making the car look short. Anyhow, it's a 100" wheelbase and a 60" track. Guess I need to create a Specifications table somewhere...
About the torque tube, it doesn't seem very popular, plus I may have miscalculated the stiffness. Regardless, the shifter's got to mount somewhere, as does the e-brake lever. Then there's all the control cables, wires, and coolant lines. If the tube is deemed useless, where does all this stuff go?
This week was spent working on the Google Sketchup chassis drawing. Google Sketch is simplistic - with its share of bugs - but it looks like it'll do fine. The chassis renderings are far from done but they give some idea of the direction I'm headed.
The SCCA rule book led to the overall layout; in fact, it's pretty much an SCCA rollcage with some wheels attached! SCCA rules state that for a car less than 1500lbs, 1.375" x 0.080" DOM tubing can be used. Great - if this size existed in the real world. Oh I'm sure that it does, somewhere, but I've been to about a dozen metal supplier sites and no one has it. Since the car's supposed to be easy to build it means no hard-to-find tubing or impossible-to-locate businesses to bend it. There's a fine line between engineering perfection and actually building something. (One of my mechanical engineer buddies is always recommending some ultimate material or part to me. I found out the hard way that while his ideas are indeed great, what he recommends is super expensive, impossible to find - or both - but I digress.) Unless I can find a source of the smaller tube - and someone with the proper tubing bender - it looks like it'll have to use 1.5" throughout.
This brings up the question of wall thickness. In terms of stiffness, 1.5" x 0.065 is better than 1.375" x 0.080, and it's lighter, but for a roll cage this may be a bad idea. Roll cage tubing may be exposed to large sideways point loads - think of a car rolling over and a tube striking a rock mid-span. Thin-wall tubing may display the "Pepsi-can syndrome": high strength in compression, tension, and torsion, but collapsing like paper if the wall is dented even slightly.
Why all the angst about roll-cage tubing and SCCA rules? Because I don't want anyone getting hurt due to me cutting corners to save a few pounds. If you want to go to thinner wall material, that's your decision, but I won't recommend it. If someone says that they don't need a roll-cage because "that's for racing, I'm only driving on the street", I think it's doubly important to have one. Meeting up with a car weighing 2-4 times as much makes for a really bad day; an accident is far more likely to happen on public streets than during a trackday event. Granted the speeds will be lower on the street but it's more likey that there'll be a collision, instead than going off the race track and rolling the car. Plus, unlike many Locosts, Midlana's roll-cage is the chassis.
Some may look at it and say that there's too many tubes. I haven't yet spent time seeing if I can delete some of them, but even now it appears that removing even one will weaken the overall structure. The windscreen is present because most states demand one, so may as well use rollcage tubing for the frame (allowing easy mounting of side wind-deflectors.) If it has a windscreen, may as well connect the front hoop to the main hoop, too. The tubes on the roof are in an "X" to allow getting in and out easily. I haven't counted, but I think Midlana has far less tubes than a Locost chassis.
Then there's that big square tube on the floor, what's with that? That's a torque tube, adding - get this - 5000ft-lb/deg of torsional rigidity to the chassis (I'm double-checking this... I may have the value wrong). This is way more than any Locost and it's only possible because the engine's not in the way. It connects the front suspension sub-frame to the main hoop, where triangulation extends it back to the rear suspension. The center tube also serves to run coolant lines, mounting the shifter and emergency brake handle, plus throttle, emergency brake lines, and shifter cables to the rear. This frees up the side tubes to be used primarily for side-intrusion protection - and styling - instead of torsional control.
Okay, about the pictures. Like I said, it's far from complete; the nose cone's left out because it's really hard to create in Sketchup. The chassis is detailed on one side only hence the lack of tubes on the far side. Also, there's a number of different ways the side tubes can be run which really change the look. I fully rendered one that looks pretty good but would like comments on all of them. Driving the design are the two curved side-panels: the small ones inside the front wheels exhaust radiator air into the low pressure area. The large ones lead into the engine compartment for the oil cooler, intercooler, engine inlet, and general engine compartment cooling. I'm also counting on the curved panels to differentiate the car from looking like a dune buggy. The rear treament I like, looking a lot like a 1930's hot rod. Louvers can be added to break up the curved panel, and to help cooling (though they're about $5 each!). The two boxes behind where the seats will be are the gas tanks; there'll be a liquid-tight panel between the tanks and the seats. The torque tube necessitated splitting the tank into two units.
The last pictures show what it looks like without windscreen - quite striking I think. However, reality is that most states require a windscreen, and being buffeted by wind can get tiring, never mind getting hit in the head by pebbles or large June bugs! As said before, the builder is going to be fully involved in the decision making process, no cookie-cutter plans here. Let me know what you guys think, as unlike with Kimini, it's important to get input. If everyone dislikes the same thing, changes will be made. Overall I'm pretty happy with the layout, which overcomes nearly all of the shortcomings that I feel Locosts has. However, I don't like that the driver's eye still has a line-of-site view with the front tire contact patch. This means sand or rocks kicked up have a stright shot at said driver's eyes - I may offer side panels to prevent that. Anyhow, let me know, good, bad, or otherwise.
Spent the day teaching myself Google Sketchup. It's a sad state of affairs that, for me, Sketchup is easier, faster, and more intuitive than Alibre Design. Of course, Sketchup is far more limited, but nothing that'll prevent its use here. The biggest issue is that I can't close out any panel I want; it's unable to produce a true 3D rendering of the finished design. I also can't do profiles or sweeps, necessary to render the Seven nose. However, these limitations aren't a big deal since the drawings are only for producing the chassis. The book will have plenty of pictures of the actual car so full-featured 3D CAD renderings aren't necessary.
I've been warned that what I'm attempting to do - design a mid-engine "Seven" - may look like a dune buggy. In my defense, the Seven's only the starting point, as Midlana's already making her own path. While it uses a Seven's fenders and nose, that's it. I don't think it'll end up looking any more like a Seven than a dune buggy - it is what it is. I think that the side treatment of the chassis will be unique, but as said, I can't render it fully to show you what I'm planning. It's still mostly wire-frame so once it's a bit more finished I'll post it for comments; just don't expect full-blown CAD because that's not what Sketchup is.
Sorry for the lack of updates; there just hasn't been anything exciting going on. More parts are showing up, including a box of Honda hardware needed to bolt on the engine mounts and the transmission to the engine. That's needed when the drivetrain goes onto the chassis table for fit-up. Which means the table needs to be built. Which means the car needs to be out of the garage. On that note, the seats showed up! They'll be infinitely helpful in figuring out the actual size of the passenger compartment. Most seats, for whatever reason, have really poor technical data supplied by the manufacturers. Plus, they're such a goofy 3D shape that it's hard to properly model them, so having the physical parts really helps.
Picked up electrical connectors for the Honda ECU. This is much cheaper than buying an entire dash harness and tossing out 90% of it. It does remind me that, as with Kimini, electrical work will take weeks and weeks. Second only to composite work, electrical is about the least enjoyable. Speaking of electrical, I may have a line on a Hondata KPro ECU; hardly required now but a nice line item to cross off.
Design work continues, including the book. There's a real advantage of writing a book in parallel with the actual design because I write everything down before I forget it. I'm also pushing forward with deciding chassis tube placement, which is more about passenger protection than torsional rigidity. Torsion resistance is being handled separately.
At the Del Mar Goodguys Hot Rod show, there were two very interested buyers regarding Kimini. One is local, the other from the east coast, and a third I met at a red light on the way home(!) We'll see how it goes.
If any of these pan-out it would be good timing. The shocks showed up this week and the seats are due in about a week. When they arrive I'm going to be very motivated to get going. If the sale falls through I'm appealing to my parents to let me store it at their place. Dad doesn't seem too excited even though they have tons of space. I'm pitching the idea that I'll visit more if Kimini is there...
The molds were sold this weekend; the new owners will be building a couple of track cars for themselves, and selling shells. They'll be providing me with an e-mail address for anyone who's interested. With the molds gone it frees up space, both in the backyard and in the rafters, which is already filled with Midlana's fenders and nosecone and whatever other stuff will fit.
Rear suspension design is progressing and it looks like A-arms will fit with pushrod suspension. That won't be for certain until everything is mocked-up on the table.
Using a detailed spreadsheet the current weight estimate is around 1300lbs. I'm trying hard to be honest and objective with all component weights but it's hard to not miss something. On-hand parts have been weighed so they're known quantities, except for the engine. That'll have to wait until the table is built and I borrow my brother's engine hoist and scales. For now I'm assuming 450lbs, same as the H22A1 in Kimini. Midlana's engine, an Acura K24A2, will have an aluminum flywheel added which will save weight, though the turbo will add it right back on again.
The spreadsheet also calculates weight distribution, 64% rear. I'd prefer 60% but if that's what it ends up being, oh well. Currently, the fuel tank is placed laterally behind the seats - it's dead space otherwise. It puts the tank right at the CG and keeps PMOI low, all good things. I think I'm going to make my own tank this time instead of using a fuelcell, mostly for cost reasons. Because the tank will be confined behind a bulkhead, and protected laterally by the engine and wheels, I'm taking the calculated risk that fuel won't end up in the cockpit. That's my choice, though builders will have a choice of either making their own or buying a ready-made fuelcell.
Received the oh-so-cool - but expensive - Tilton bottom-pivot brake assembly. Still waiting on the shocks, and while they aren't really "needed" for a while, they'll serve as a nice psychological push forward. Also, the seats should be showing up in the next few weeks. Once that happens it'll mean everything's present to push forward, which means I'll be itching to get parts on a table. And that means moving Kimini out of the garage, one way or another.
Checked out my brother's nearly-completed Super Stalker. All that's needed is to paint and install the fenders and paint the engine cover. He's been driving it a few weeks now so first he took me for a ride, then let me drive, then I let him drive Kimini.
Driving observations:
His car has TONS of low-end power thanks to the supercharger, the problem is getting it to the ground. The long wheelbase and steering rack results in a rate about half of mine, and I may have the same issue with Midlana. A slower ratio is better for the street, though I'm curious what he'll think about it on-track. Probably the biggest difference though is ride quality. He went on a road that has two bumps in it, one upward and another downward. His seats have less padding than mine, but when we hit those bumps, it was a real harsh blow to the backside, enough to make you wince when you approach it. The wind whipping around the windshield wasn't as bad as I had previously experienced in a Caterham. He said that's probably because he made the windshield both 2" wider and taller. The exhaust sound is pretty loud, obviously due to its proximity to our ears, but made worse by the low frequency nature of the V6. At a certain speed and engine load, it all resonates, like someone feeding 100Hz into your headphones and cranking the volume way up. He said it's loud even with earplugs because they don't filter out low frequencies well. He may try pointing the exhaust tips differently to see what happens. Oh, and now that I've driven both a high and low-pivot pedal setup, I'm not concerned about the differences. Yes, the brake pedal arc does lift your shoe off the floor, but it simply isn't a big deal. After a couple minutes I didn't even notice the difference.
His observations of Kimini were that it was much more refined, much quieter, and that the steering was much more sensitive. When he drove over the same two bumps he couldn't believe the difference. That's the day-to-day consequence of having high unsprung weight and little suspension travel. Examining the rear suspension showed that it has only about 1.5" of compression travel so he may try relocating the shocks to free up some travel (allowing softer springs and shocks.) He's also looking into stiffening the shocks and swapping in stiffer springs.
No, we didn't drag-race. We both agreed that the two cars are very different animals and we both respect the other's car enough that there's nothing to prove - each has its strengths. I think his is faster in a straight line, but only if he can get the power down. In the curves, who knows. There's no way to properly compare the two outside of a racetrace. Having driven his car, I can't understand why anyone would want more power. First and second are useless if you hammer it, and third is a dicey proposition if it's not pointed straight or if the road's not smooth. All more power does is make more smoke, so he's getting wider and stickier tires to help cure that.
The front push-rod design went smoothly thanks to the Mitchell software. The design freedom of pushrod suspension is great since it allows achieving all the goals: placement, accessibility, aesthetics, and the target spring rate.
Ordered double-adjustable QA1 shocks with 6" travel, identical units being used at all four corners. Also ordered the uber-cool Tilton pedal set, never mind the price. Next will be the rear suspension design, starting with carefully measuring the Miata rear upright.
A long-term background exercise has been the chassis side treatment - how to make it clean, elegant, simple, yet functional. I should mention that while the car started out as a "mid-engine Seven" visually, it has diverged somewhat over time. All the various parts require small changes to the initial body shape; the end result is that the finished product will have its own unique identity - good.
A hanging pedal assembly isn't going to fit - nuts. It shouldn't have surprised me; the hoodline is pretty low, and some (most?) Locosts use bottom-pivot assemblies, so what did I expect? Guess I'll just have to deal with the different feel. Tilton has a very nice floor-mount assembly that includes clutch, dual brake plus balance bar, and throttle pedal, but it's expensive. While they can be built from scratch, pedals are kind of, um, super critical. I think I'll pass on designing them for safety reasons and go store-bought. If builders want to make their own, the Gibbs book already shows how. Buying one saves time and lets me get on with the design, and there'll be enough room that builders can decide which way they want to go.
This means I have a new Tilton pedal assembly for sale, part number 72-620. It's a steel, two pedal, three cylinder assembly, with the master cylinders pointing toward the driver. It does NOT include balance bar or master cylinders. It sells new for $234 through Taylor Race Engineering, but I can't expect full price, so I'm asking $175 plus shipping. It'll head to Ebay this weekend if no one grabs it.
Regarding the shocks, I've decided to go with QA1 double-adjustables, about $260-$290 each. Like much of the design, builders can choose whatever shocks they want as long as they're the same size and use the same spring rate. Between the expense of the shocks, pedal assembly, and my brother having bought corner scales that I need to pay half of, I'll have to pick and choose what to get first.
The front suspension pickup points have been chosen, and next is working out the pushrod and shock setup. I'd like to make the shocks a feature, visible from outside, but it'll be a challenge to miss the driver's feet, steering shaft, pedals, master cylinders, radiator ducting, etc, etc. Checking brake master assembly clearence though, shows there won't be any choice but to use a bottom-pivot assembly. There's simply not enough vertical space for an overhung type, even with remote cylinders. One perk of a floor or firewall mount is that I don't have to snake the steering shaft through the pedals, or avoid putting the shocks there.
At the Cars and Coffee event were two really cool cars. One was an original Cobra, not that big a deal around here, but this one had a polished aluminum body, just like chrome and very impressive. The other was what appeared to be an unrestored Toyota 2000GT. I never thought I'd get a chance to see one in person; they're just beautiful cars, very elegant. It's a shame they were never imported; they could have outsold Datsun's Z car but I think they were too expensive. A real shame. Interestingly, it was parked next to a Ferrari Daytona, allegedly the inspiration for its styling.
The network problem was an intermittent router, which was a real pain to figure out. A number of times I tried bypassing it to see if it was the problem, but it had apparently already messed with the computers, so it appeared that the modem was bad, or that the problem was with the ISP. Anyhow, a new router fixed everything, and it's all running much faster than ever before. I think the old SMC router was going bad over a long period of time. Linksys stuff rocks, plug it in, turn it on, and it just works, no drivers to install, no settings to mess with - nice.
Alright, back to suspension design.
Battling network issues. Darn computers...
The readers have spoken; the front suspension shall be push-rod. I won't know how the rear suspension will lay out until I get to that part of the design. I suspect it'll have to be push-rod, too, due to the deep wheels. Even though most builders will use narrower wheels than what I'm using, I have to design it to work with the widest wheels that the design will accommodate.
Ordered a set of fenders from Kinetic Vehicles . They'll be handy to have during mockup of the rear part of the chassis, nevermind that I'll need them eventually anyway.
Oh, and it looks like I found a buyer for... no, not the car, but the molds. They would have gone with the car, but the lack of car offers meant I was happy to find a buyer for them. It's just as well; had they left with the car, they would have essentially been given away for free.
After thinking it over, and hearing from readers, I've decided to stick it out with the Miata rear uprights. As several people pointed out, I'm supposed to be designing an easy-to-build, simple car, not something where all sorts of different donor parts are needed and custom parts fabricated. Okay, lesson learned!
Speaking of features on the car, I have a reader question: Do you want push-rod suspension or traditional outboard suspension? Push-rod suspension: looks sexy, good stock travel. Cons: heavier, more complicated, takes up space inside the chassis, takes longer to build, more expensive. Outboard suspension: simple to build, easy, cheap. Cons: not great shock travel. Your choice, pick your poison!
My brother just started driving his Super Stalker, even though it's not complete (hood's not painted, no fenders or mirrors, etc). He said, "First gear is useless... second gear is useless, third gear is, oh crap!" I guess he's impressed.
Forgot to mention that I took Kimini up to the "Cars and Coffee" event. This has turned into a huge deal, with hundreds of cars and spectators. Nearly everyone's there by 7am, and nearly everyone's gone by 9am(!) which is cool because it leaves you with practically the entire day for other things. As cars start leaving, a crowd gathers at the exit, cameras in hand, to watch and listen as some exotic machinery leaves. In fact, there was a Ferrari 250GT there, or something that was so close to an original it had people all excited. Anyhow, I don't post pictures any more because there are 100s of people who do so now. All you have to do is Google "Car and Coffee 3/1/08". This search works every week, just change the date. That's how I found this YouTube video of all the cars leaving last Saturday, including a little gray Mini! I appear at 5:35 in the video.
In other news, I'm closing in on the front wheel geometry. Because I'm making the front track wider than the usual Locost, it presents the opportunity to use an unmodified Miata steering rack. People have a lot of trepidation about modifying steering racks, so this both simplifies and speeds up construction. Moving links around and juggling the wheelbase made it all work out, so unless something nasty shows up, this iteration looks promising.
The second set of rear uprights arrived, setting a new record in poor packing. Styrofoam peanuts don't protect 40lbs suspension parts, so they punched a hole in the box, which arrived half empty of peanuts, I'm sure UPS appreciated that. I'd be upset if they were broken, but thankfully suspension uprights are darn tough. So portions of these may be used instead of the Miata rear uprights. As much as I look at the Miata parts I just can't figure out how to make a clean, easily adjustable rear suspension with them. While the alternative design requires fabricating custom uprights, the bolt-on spindles don't require making precision bearing cups. (This adheres to my goal of making the car producible without requiring a lathe.) I'm curious what people think though, about making suspension uprights if it is an improvement over using the stock Mazda parts. Of course the question becomes, "How much better would it be? Is it worth the extra work?" I hope to answer that soon. It's the eternal compromise, do I use parts which are just "okay", or require extra work to make it much better? It's a thin line between doing it right and getting it done.
Been working hard on the front suspension design, which is testing my nerves - just like 12 years ago. Since I'm using Mazda Miata front uprights, I wondered what kind of numbers Mazda used. The internet revealed the stock suspension points, and even if they aren't exact, the Miata's setup is very interesting! What I find fascinating is how Mazda doesn't "follow the rules" by keeping the roll-center stationary, not even close. But if it's examined using force application points, figuring that the outboard tire carries most of the load, then it works. Of course, the reality is that it (the car) works just fine, as Miata owners will attest. Still, it's very interesting how Mazda's setup "violates" the stationary roll-center rule... very interesting indeed. So, good, this means I can press on with my original suspension design and hopefully have some good numbers this week. Once the front suspension is done I can start working my way rearward.
Bought the domain www.midlana.com, the future site for Midlana builders. Granted it's quite early to do this, but I didn't want to find the domain gone if I waited until later. Looking into various forum software packages, though I'm not sure what I'm signing up for, probably hours of removing spam for enlargement devices, Nigerian bank offers, and on-line pharmacies, lol. About the next book, I may do the distribution myself so that I can serialize each one, each book number becoming the chassis number for that builder's car.
The garage is filling up with stuff, with few nibbles but no offers on Kimini. I realize it could be a long time before finding a buyer; I need to get off my butt and start advertising more seriously. I figured I'd post it here first to give longtime readers first shot at it, but all it proves is that the Internet will beat a path to your door - as long as everything's free. So I'm going to start showing it at the "Cars and Coffee" event in Irvine, CA, where some very expensive hardware show up, along with some rather wealthy car nuts. That venue should be good for finding buyers.
A buddy said I should have held off buying an engine (which will always be the case.) He said the one to have "today" is a direct-injection turbo engine. The big advantage is that there's no detonation (no fuel in the combustion chamber until needed), so a turbo 10-11:1 engine has very little lag. Oh well, there's always something better that'll come along. Eh, I'm fine with what I'm doing, and like I said, there's always a better engine next year.
I'm reminded that I'm leaving out project details again. It's not on purpose, I simply forget to include them. The suspension uprights are Miata all around. While they're not perfect, the reality is that they're widely available and affordable. Going through the design process with Kimini taught me how make things easy to build. While Kimini has excellent suspension geometry, it's because the front uprights were heavily modified and the rears fully-custom fabricated. That's fine if you don't mind spending weeks and weeks making them, including using a lathe to fabricate bearing cups to an accuracy of 0.0001". However...
That said, I'm not sure I like the Miata rear uprights. Even as I work through the front suspension, I'm eyeing them with more of a glare than satisfaction, especially the top suspension mount. In the Kimini book I note how some builders used bolt-on rear spindles - and how much easier that is than making bearing cups. In fact the latest Locost book specifies fabricating rear uprights using bolt-on Ford Sierra hubs. I'd use something domestic, but I'm torn between making the car fast and easy to build and slightly slower to build but having better rear geometry. Of course the question becomes, "How much better would it be?" I'm certain enough of my, um, uncertainty about the Miata parts that I've already ordered a different pair of rear hubs that bolt on. This allows making a fully-custom upright with the pick-ups where I want, unlike the Miata parts that force the issue. It's too early to tell which path will be taken, and so you see some of the endless behind-the-scenes dithering going on. Again, whichever uprights don't work out, back to Ebay they go.
More goodies. The nose is from Kinetic Vehicles and is their "catfish nose". Since I don't have an engine up front I want to run a lower profile nose, and here it is. The styling is, as I was warned, going to be tricky, since Locosts are narrow vehicles. I've made things hard on myself because I've pushed the passenger compartment foward. This means the body taper is going to be tough to match up with the taper of the nose cone. The question is, can I make it work or is it going to look bad? Of course the nose can be widened, but the goal is to try to use it as-is. That way I - and other builders - don't have to mess with composite at all. That said, I suspect it's going to have to be widened anyway, but we'll see. If a decent number of people decide to build the car, I'm sure Jack at Kinetic will be willing to build a wider mold, ;) Designing the suspension around the nose is a bad idea, as compromising proper wheel control to work with the nose imposes a lifelong handicap on the suspension. So, now starts the endless interations to settle on a workable wheel track.
I have some ideas about how the chassis sides will be styled and I think it'll look pretty sweet - clean, functional, yet bold, if I do say so myself. Of course people may look at it and think, "Ewww", so we'll see, lol.
Also received a K20A2 oil pump and pan, necessary as part of converting the K24A1 engine to the high performance version. The transmission should arrive next Monday.
The last picture is my bestest buddy, Cooper, who likes to rest his heavy head on my knee, tug-of-war rope in mouth, all ready to play. He'll sit there for quite a while, figuring - correctly - that I'm well aware of the message he's sending.
It's here... a Honda 2.4 liter K24A1 and a K24A2 cylinder head! The engine will come apart, in preparation of getting oil squirters added and honing the cylinders for the new rings (and pistons). Compression will be lowered to 8.5-9.0, for running boost on our crummy 91 octane gas here in California. While lots of people say I don't need to lower compression, I have a good buddy that built all sorts of crazy Honda engines, all the way up to 1200hp drag racing monsters. He said that all it takes is one long hill and being in the wrong gear to cause detonation (pinging) which will very quickly destroy the engine. The plan is to design every part of the engine for 400hp, but run it at a more "reasonable" 300hp.
A little more infomation about oil squirters, these are oil nozzles mounted in the block that squirt oil up at the bottom of the pistons. The idea is to keep the pistons cool to avoid detonation, yet there's a lively debate on the forums regarding the need for them. Some people say that switching to forged pistons negates any need for them, while other's say anything that keeps the pistons cool is a good idea, which I agree with. Factory stock pistons are cast aluminum. This means that as the engine gets hot, the coefficient of expansion for both the piston and cast aluminum block is similiar, so as the piston gets hot the piston-to-cylinder clearance is maintained.
In a boosted engine however, it's common to swap in forged pistons which are far stronger and more resistant to detonation. However, since they are made different, their coefficient of expansion is higher than cast pistons. This can be a very, very bad thing if the engine is run hard (like up a long hill or on a road racing track). The piston keeps getting hotter and hotter and expands faster than the block. Eventually it expands enough to start rubbing on the cylinder walls and once that happens, they get really hot and completely lock up the engine. Sooooo, oil squirters seem like a very good idea to me!
I'm not sure when the engine build will happen, probably in parallel with the chassis build. The goal is to have it done before the chassis is finished. In fact, I'd like to have it done before it's time to put it on the chassis table, but that's probably optimistic.
Returned the brake rotors - they're just too heavy - backing off to "regular" brakes instead of the vented Sport discs. The weight made me give up whatever additional cooling capacity they have. The solid rears are roughly half the weight of the 12lbs vented units. If there's any heat issues, cooling ducts can be added, upgrade the pads, or go to vented rotors as a last resort.
Found an engine; it's paid for and will be here in a week or so. Found a transaxle, too.
The brake discs are VERY heavy, 13lbs each for the fronts, and 12lbs for the rears. This is due to going with larger vented rotors than solid discs. I had been assured that small solid disc brakes will be fine... so I may take these boat anchors back.
Okay, I've saved the bombshell for last, though it probably won't be a big surprise to regular readers... I'm going to be selling Kimini
On the front suspension, I've got a good design candidate, though it'll have to wait for the front nose; only then can the inboard suspension points be fixed. Wouldn't help to fix them now only to find the nose is in the way.
Regarding the sportbike shocks... the more I think it through the less likely they're going to work due to the spring rate and shock travel. With shock travel of 1.5" (or 2" if I shorten the bumpstop), the 595lb/inch spring rate's probably going to be too low. This is what happens due to all the leverages involved and the short stroke. While the springs can be replaced with stiffer ones, the spring rates end up getting ridiculously high... a shame. It's not a closed case yet, but if you feel they can work in your project, drop me an e-mail, otherwise they'll end up back on Ebay. If that happens, I'm right back to where I was with Kimini, facing the purchase of $300-$500 shocks, ugh, this was supposed to be low budget. Eh, what I'll do is specify a coil-over shock of common length. This will allow builders to go "economy" or "nuts", as their budget allows.
Ordered the nosecone and brake rotors so that front suspension design can progress. The nosecone is for determining where the inboard front suspension pivots go. The brake discs are for measuring the thickness at the mounting face, as it shifts the wheel center outward. I'm told it's 7mm, but I feel better measuring them - and every other component - myself. The seats will probably be ordered next.
I got a great deal on a Tilton hanging pedal set, but after seeing how compact, low, and light my brother's floor-mount pedals are, I wonder if I should go that way. Than again, when I tried them I experienced what other people have said about floor-mounted pedals. The arc of the pedal and foot don't match, lifting my foot off the floor. Not terrible, but something that would take some getting used to. I'll have to think about it.
Got the wheels today and boy they're big, and blingy! These were bought because wheels are next on the list of must-haves after the tire sizes were chosen. These will be for the street, so they ended up more towards the appearance end of the pool as opposed to function. I'm trying to contain costs more than with Kimini so it means going with heavier wheels than I'd like. What I get in return is a stronger wheel so I don't wince whenever I hit potholes. These are literally three times cheaper than proper race wheels - though about 7lbs heavier - but so be it.
The wheels are Sport Max 006 wheels, 17 x 7 fronts, and 17 x 9 rears, both in 4 x 100 bolt pattern, which is unusual for this size. These are apparently sold to drifters driving Nissan 240SX cars. They aren't perfect but they'll serve their purpose just fine and at $130 each, it was too good to pass up. Before I hear, "those are way too big, 17" is dumb", keep in mind that since the design spec calls out only tire outside diameter; the builder is free to choose a different size. That is, any tire from 14" - 17" will work just fine. I chose 17" because it's my opinion that it "future proofs" my wheel choice for a long time. This is my reaction to getting bit from dwindling 13" street tire sizes with Kimini - I don't think 15" tires are far behind. Once burned, twice shy. Also, this guarantees that when builders slap on 9" wide race wheels, they'll fit just fine.
Looking at another engine for sale. I keep flip-flopping between building a high-reving normally-aspirated engine and a forced-induction solution. Either way it's going to require changing pistons and rods, and I recently came across a partly disassembled project engine that has neither - perfect. I'd have to take it apart anyway, and with it disassembled, it's much easier to check out.
Finally tested the coil-over shocks with a proper press and load cell. As suspected, there's a sizable gas preload pressure before the shock starts to compress. It was a lot of fun, actually, as I rarely have the proper tools to do this. I'm always having to guess or approximate what I'm doing due to not having the right tools, always making me feel bad about doing a half-assed design job. However, when I've got the proper tools it's a really good feeling knowing that the data I'm collecting isn't "roughly" this, or "about" that - it's exact. With this data I can confidently design the push-rod suspension, and know it'll work first time. That's a great feeling to have even before it's built.
After 25 years of resisting, I've finally given into having two sets of wheels and tires, one for the street and one for the track. Given that, I've backed off on buying the lightest street wheels possible, since they'll have to deal with potholes (and bonehead tire installation shops...) Street wheels are far from lightweight, but then again they cost less than 1/3 that of a really light racing wheel. So it was a bit surprising to come to terms with buying something that isn't the best. Yup, today, street wheels were ordered. Theoretically they aren't needed but they're invaluable for suspension mock ups and checking for clearances. Having CAD is pointless when detailed dimensions are unavailable, which is a lot of the time. Wheels are especially bad in this respect, and it's a rare manufacturer that supplies accurate cross-sectional drawings. The best anyone gets is bolt pattern and back-spacing.
The ultralight track wheels that cost crazy money will come later, after the car's built and ready for the track.
And so it begins. Having decided on a 23.5" diameter front tire the real suspension design starts. Using Mitchell's excellent WinGeo3 software, I'm working through many iterations, trying to get static FAPs (Force Application Points.) What's frustratingly familiar is how I can get static FAPs, and roll centers for that matter, but I'm not happy with the camber gain curves yet. I'm not complaining, and quite enjoy the iterative process. It's a good feeling knowing that once this step is done, the car will have a stable, predictable nature to it, just like Kimini has. And like the Mini, it took weeks to gradually settle on those elusive points in space, about which the suspension will pivot.
I've chosen the tire diameters... almost for sure. They're going to be 23.5" front +/-1/2", and 25.1" rears +/-1/2". Might still change my mind, but that's the values for now. Made up adaptors for testing the shock this week. Better to do the testing safely rather than propelling the shock across the room at 800mph because it slipped out of the press...
Regarding the shock, I know that the spring rate is around 500lbs/inch. The problem is that it's preloaded, and the high-pressure nitrogen adds to the overall rate. This gives a discontinuity, where nothing happens for several hundred pounds until it finally starts to compress. Until I plot points at higher force I won't know what I have. This weekend I'll make brackets to properly support it and run a force vs. compression test on Monday. Oh, and another impressive feature of the shock is the mount bushings. I pulled a bushing out and there are needle roller bearings inside - very cool! My expensive Konis don't have that!
While a great value, I can see a potential problem using these shocks, which is a shock travel versus spring rate issue. That is, I can trade one for the other, which is fine if one's not important. Unfortunately there's a squared term in the installation ratio (as I was reminded!) which makes things even more interesting. Instead of getting all wound up over this I'll remain calm until I get it all into the suspension design software to figure it out. Worst case I have to use different units at the back, or swap springs, which isn't so bad. That's part of the beauty of buying off Ebay. If you buy used stuff and end up not needing it, you can sell it for virtually the same as what you paid.
Several Locost builders I know have used these shocks so I know they can work. Of course a couple of them have sportbike engines in their cars so the very low weight translates to lots of suspension travel. I'm going with a heavier but more "polite" street engine which will eat into the little shock travel that's there. Guess I'll be the first to know if it works or not!
On the tire front, I'm going to try to decide tire diameters this weekend.
Received the sportbike shock. It's a high-pressure gas shock so it has quite a bit of preload, in addition to the spring rate. I was able to test it to 240lbs, resulting in 0.10" compression (which is pretty nuts because it implies the spring is 2400lbs/inch - I don't think so!) This single data point is useless without higher loads but unfortunately I maxed out the poor bathroom scale. Not sure how to do this, unless I rig up a big lever arm and figure it out geometrically. I need to find a big hydraulic press with a pressure gauge on it... and I think I know where one is.
Still haven't settled on a tire diameter but I'm closing in. Throwing myself on the mercy of a couple forums I'm getting some good input, though I think many people are still thinking 15" tires will be around a long time. I remember thinking that about 13" tires... "once burned, twice shy". Making the tire decision is a big deal design-wise, so big that I've been putting it off.
Tires:
Tires are the most important - and most frustrating - decision during new car design. Nearly every suspension design parameter is related in some way to tire choice. I'm owing to stay away from hard-to-find 13" street tires so it means going larger, to 15" if not 16" or even 17". I've spent weeks going back and forth between brands, trying to settle on a size that everyone will be able to find, both now and over the life of the book. This very likely means going to 16" or 17" to guarantee some non-obsolescence. Yes, larger wheels and tires have a higher polar moment of inertia, weigh more, and cost more. On the other hand is the possibility of simply not being able to find what I specify, so the former outweighs the latter.
Before people jump up and down saying that it's easy to find 13" and 15" tires, well yes, and no. Sure they're out there, and they'll continue to be for some years; the problem is the compounds. For as light a car as is being designed, high mileage tires are neither needed nor desired. This thing's not going to driven in snow or rain (much) so all-weather tires aren't wanted (besides, it's a sports car). We need what tirerack.com calls "Ultra Performance Summer Tires". This greatly cuts down the list of contenders, and even the list of high performance 15" tires is getting thin, about how it was with 13" tires when I designed Kimini. Note that this only applies to street tires, NOT race tires. For the track, getting 13" and 15" tires is easy, yet that's not the starting point of this project - it's going to be street-legal. 14" tires aren't mentioned because they never were a popular size and are fading fast, there's no reason to even go there.
So in an effort to design in some staying power, the tires may be larger. For the moment, my sole concentration is on choosing tire diameter, a primary design concern. At this point, whether the tire's made for 13", or 15 - 17" wheels is immaterial. However, when I read tire data and see that there's a grand total of only one or two 15" sizes, the writing's on the wall.
Spent a few hours carefully measuring a front suspension upright to load the dimensions into WinGeo3. It's time consuming to find the center of rotation of balljoints. Yes, in the interest of reliability, availability, and cost, I'm specifying stock balljoints at the outboard ends. That makes it easy for the builder to get them from any parts store.
Shocks:
Those who read the Kimini book recall my angst over shock selection and pricing. Good shocks are very expensive; I recently saw a new astronomical price for one shock... $2000. I say unless it comes with topless maidens who install it, I have to wonder what the price gets you. Maybe it includes having Michael Shumacher fly in and drive your car. Anyhow, I'm wondering once again how I'm going to deal with the expense. The shocks, by necessity, must have adjustable ride height and adjustable valving, preferably being double-adjustable.
In the back of my mind has been to use sportbike motorcycle shocks. It's nothing new; people have been using them in Locosts for a while now, though many builders are clueless about spring rate versus installation rate. They change the springs to make it all work, then wonder why they can't set the shock valving the way they want. Anyhow, new bike shocks are also expensive, too, BUT, many bike owner remove them when they upgrade the suspension. That's excellent news for us because they end up very cheap on Ebay. As a comparison, the Koni shocks on Kimini are about $500 each, plus a $50 spring. The price of a used sportbike shock and spring is $40-$50. Yes, about 10 times cheaper. This is a huge reason to consider them even if they aren't perfect. Heck, the saved money can easily pay for the entire drivetrain! Bike shocks can work in a car; the secret is to use them as-is, without changing spring rates. That's because the shock valving is made to work with a specific spring rate; so as long as it remains unchanged, it doesn't care what it's installed in.
This brings us to the next topic, whether to mount the shocks in the traditional outboard position, with the outer end on the lower A-arm, or to use pushrod suspension. The traditional position is simple, easy, light, and easy to adjust. Using pushrods means more joints, a pushrod, rocker-arm, and potentially burying the shock inside the body where it's hard to access. Pushrod suspension came from Formula One where they had to get the shock and spring out of the 200mph air blasting over them. It allows putting them just about anywhere, which is important due to underbody airflow management. We have no such problems! However, many people think pushrod suspension is cool (and it is) but is the added complexity worth it? No... and yes. Technically it's not, and completely silly, adding unnecessary complexity and making adjustment a potential pain. BUT, what overrides these objections is the $1800 we save. It means we have to compromise our "technical reasoning" on a cost basis.
(This reminds me of something Dave Norton (Shrike designer) said about push-rod and rocker-arm suspension, "Just because you CAN design something doesn't mean you Should design it." He was referring to the added complexity versus what it does for performance. I have to agree with him.)
Because of the complexity I had no intention of using pushrod suspension until I found how inexpensive motorcycle shocks are. Due solely to pricing, it's probably the way to go. It does mean adding two rod-ends and a rocker-arm bearing. The one problem with designing in specific motorcycle shocks (and writing a book that uses them) is that over time, that particular unit will become hard to find. To offset this, I'll choose one from a popular (therefore, common) which will hold off the obsolescence for a long time. Lastly, the ride height adjustment on the shock is unusual, using a ramp-type ride height adjuster instead a threaded collar. This could present a problem, BUT, push-rod suspension lends itself well to adjusting ride height elsewhere, by changing the length of the push-rod. So consider the decision made.
I realize I haven't described what Midlana looks like. While the details are still squishy, it's basically a Lotus Super Seven with the passenger compartment pushed forward enough to allow a transverse drivetrain behind the driver. It's not original (what is?) as there's one manufacturer in England (Sylva) that produces one now, the Riot. Will Midlana be a knockoff of that, no, though all these cars are a knockoff of something. No, it'll be its own thing, but will use commonly available composite so the builder has little or no messy, stinky composite work to do. It's going to be "buildable", easy to maintain, and inexpensive.
Thanks for all the comments regarding seat placement, sorry I couldn't respond to everyone separately. I think I'm going to stick to the traditional side-by-side placement. It's a combination of reasons: routing the seatbelts, not getting undue attention from safety inspectors, motor vehicle registration people, and later, cops, and, being able to hear, say, a driving instructor. From a selfish point of view, it'll be much easier to get it through registration in California if it looks like a "normal" car. Then there's the "too different" aspect; I'd like this car to be something people want to build, and the center seating might be a bit much. I know I'll never make everyone happy, but alienating a huge group right off the bat's probably not a good idea!
Engine choice: The builder will have a decent-sized bay to install whatever they want (with limits). Everyone has access to different engines due to differing budgets and regional availability. Then there's form factor. There are many transverse FWD drivetrains out there, all with similar layout; that's the type that Midlana will accept. Of course there are other engines like the Subaru flat-four: low, light, with a "real" transaxle. The problem is that the transmission tail shaft sticks out quite far past the axle centerline. That's of no consequence if the car's designed for it, but it's not. A transverse layout is shorter, front to back, which packages much nicer, and there's the rub. There are far more transverse drivetrains out there than Subaru drivetrains, so I didn't want to force builders to use only one engine brand. (Technically the engine bay could be made large enough to fit everything on earth, that it gets out of hand. This is the consequence of following a cookbook; you're stuck with the designer's vision.)
I have a question for you. If you had a choice of building a car with two seats side-by-side, or two seats, one behind the other, which would you choose? In the first case, the car could be considered more "sociable", in that you can easily talk to each other. This is important, but I'm not sure by how much. I mean, how many people do you Really give rides to? Does your spouse Really love riding in the car, or is it more to be polite and put up with your crazy hobby. Or...
Do you compromise the social aspect of it by putting yourself front and center, like driving a "real" race car. Also, the car wouldn't have to be all that much longer since the rear passenger's feet could straddle the front driver's seat. There's no pesky driveshaft tunnel to fool with, so that's not an issue. Hmmm, something to think about, but I'd like comments either way. I think I know the answer, that it's just a bit too "different", but I'd like you to consider what you get (as a driving experience) before discarding the idea.)
It suddenly hit me today that unlike Kimini, where I did anything I wanted and didn't care what anyone said, now I have to care what people think! It'll take some readjustment, having to listen to what people want! Or do I say, "This is how it is, take it or leave it." That doesn't do well to sell books with that kind of attitude.
Let me know. Of course, none of this is going to happen unless I find a drivetrain, darn it!
How quickly things change. I've corresponded for several years with Mark Warner, author of "Street Turbocharging." He and I have exchanged ideas on writing, my project, and forced induction, and today he give me a bit of a wake up call. He, no doubt voicing unsaid feelings from many, firmly let me know how he felt about my "smoke and mirrors" act - really poor form. After some long and deep reflection, I agree with him - it's just not me. I'll knock off the games and be more open about what I'm up to. In fact, I was ashamed enough of what I wrote last night that I removed the worst of it.
Regarding how quickly things change, just this morning I was very, very close to getting a great deal on pistons and rods for my chosen engine. Then, I started thinking about it all and canceled the deal, but let me back up and explain. I preface this with, once again I'm going mid-engine.
My brother, who's using the GM supercharged 3.8l V6 in his Stalker, of course thinks that it's the no-brainer obvious choice. I said there aren't decent transaxles for it, and adapting one to it seemed silly, but he said with enough effort I could make it work. Exactly... I don't want to reinvent the wheel when there are already FWD drivetrains waiting to be used, and not really heavy one's either. I'm comfortable with Honda engines, having built Kimini using a Honda H22A1. Because of the awesome aftermarket support, both in parts and forums, I've decided to stick with them.
So over the last six months I've been thinking about which drivetrain I'd like use. While Midlana will accept many drivetrains, I still had to pick mine. Naturally I was drawn to the largest 4cyl that Honda makes, the K24 series (2.4l). There are four variations, going in the CRV, Acura TSX, Euro Accord, and USDM Accord. Each has different power levels, with the TSX being the highest, Unfortunately for that very reason, it's the most desirable and sought after. On the other hand, the Accord, making about 20% less power, is typically about three times cheaper - really. Many people convert these over by adding a better head, changing the pistons, rods, and so on. It wasn't until today that I started rethinking my whole engine selection. If I get the Accord engine, I'll have to build the engine before I can use it; that wasn't the intent at all, I want to drive the car as soon as it's on its wheels. Then I started adding up the costs of getting a Accord engine to what I want and was surprised that, for the money, I could just go straight to a 200hp TSX engine. It's a slam-dunk solution; buy it, put it in, and I'm all set. Even better is that when I go forced-induction, zero internal modifications are needed.
So there you go, my first step in being more open. Of course, even with me explaining what I'm doing, don't expect what I say today is true tomorrow, as I'm full of vague nebulous ideas that come and go all the time. Just because I come up with something doesn't mean it's going to stick around, and it can be discarded like yesterday's Hollywood starlet. On the other hand, I realize people like reading along, following my thought process, be it smart, or completely idiotic.
So while this doesn't spill all the beans, it's a start. However, the more time I spend typing this is less time I work on the design, so I'm off to work on that. I'll discuss the plan in more detail in future entries.
A kind coworker let me take dimensions off her car's drivetrain, the make I'm considering using as donor. This is an important step because, even though many engines will fit Midlana, I want to make absolutely sure that mine will fit, too.
Well, vacation has come to an end, though I managed to cross some things off the to-do list: cleaned the garage, made good progress learning CAD, and added pages to the book manuscript. Also received the suspension design software from Wm. C. Mitchell, along with an amazing suspension book by Rowley. Between these two I'm ready to rock and roll.
Oh yeah, I wore out the little electric RC helicopter, surprisingly, not by crashing it; the tiny plastic gears finally stripped out. So of course I fixed that by buying a bigger helicopter ;)
Looks like, as with Kimini, I'm going to have to buy a drivetrain if I want to know how big it is. People's generosity apparently doesn't extend to taking the time to help me measure certain drivetrain dimensions. A little disappointing, but about as expected. Short of that, I realized that a coworker has one of these cars so I guess I'll be measuring her... engine.
Got an electric helicopter for Christmas, which is surprisingly capable for the low price. Great fun flying indoors, as long as Cooper doesn't get at it. From his point of view, it's a big bug that invaded his space!
Spent the day cleaning out the garage, and it's far more pleasant now, not stepping on boxes and stepping in grit everywhere. Of course our trash can now weighs about 250lbs... I wonder if the trash guys will complain. A clean garage is a vacuum, wanting to be filled with something. I'm working on that.
Here's a picture of my brother's Super Stalker taken a few weeks back.
In celebration of $100/barrel oil, here's a picture I took on the way to Button Willow. Someday we'll look at this picture and think, "I remember when it was that cheap..." I think it's going to have to go to about $10/gallon before people really start changing their ways.
Ordered WinGeo3 4.03 from Mitchell Software. It's one of the few (and perhaps the only) suspension software packages that uses force application points instead of kinematic roll centers. I've become aware of this different design approach recently and will use his software to learn the differences, and to design MidLana's suspension. It also cleanses my soul - slightly - by finally paying him! See, I had used a very old DOS-based copy of Mitchell's FreeBody software to design Kimini's suspension...
Sorry for the lack of updates, things are happening, just slowly. Received the uprights and the steering rack, parts needed before suspension design can start. I also need to choose tires and wheel sizes... not necessarily buying them yet (like I did with Kimini, and have the tires harden for 10 years, but I digress) but a size is needed as they're part of the overall suspension design. I'm currently deciding between 15", 16", and 17", since I've given up finding 13" street tires.
Started reading up on potential drivetrains; I'm pretty sure I know which one I want. It's now a matter of finding weight and sizes, which is much harder than it should be.
Learning CAD is frustrating, to me at least. My creativity shoots miles ahead, then stands around waiting for me to use the tools in order to achieve the vision. I don't blame Alibre Design; I'm just too dumb to know how to use it yet. I don't have the luxury of using Alibre at work (or any CAD for that matter) so it's taking a long time to learn. Instead of making drawings of every tube, there will be one fully dimensioned master drawing. The reasoning is: because metal moves when welded, and tubes are never cut exactly the correct length, exact dimensions are useless. If "Tube 63" is specified to be exactly 12.48574532" long, with a 43.2 degree angle, but the space it's supposed to fit into is physically 12.5" and 45 degrees (due to cut errors and welding distortion), what good are tube drawings? Said another way, having one master drawing means that target dimensions are given, not exact hard numbers. This makes it clear to the builder that while the values are theoretically exact, it's very likely that the space it's to fit in won't match the drawing exactly. That's okay, and it tells the builder that he can, if he wishes, correct the error then, make up for it later, or just not worry about the slight inaccuracy.
Over the break I plan to clean the garage, as boxes have been creeping onto the floor over the last couple years. Freeing up room gives extra space for, oh, new things. Where Kimini's going to park once construction starts is something that'll be dealt with then.
Merry Christmas everyone! Oh, and I have a name for the new car: MidLana. Mid because it's mid engine, and Lana is our granddaughter's name. I like the sound of it, and it's unique on the Interweb... it'll just take a while before people can remember it off the top of their heads. Hopefully - this time - the car will be done before she's 10 years old!
Create project weblinks and screens. Starting in on learning CAD... it's going to take me a long time since I have so little time after work (long work days again.) That'll improve after mid-December.
What's happened so far? Lots of thinking, in fact it's all designed in my head except for styling details. Bought suspension uprights; they're the first parts needed since everything depends upon the outboard pickup points. As said elsewhere, the plan is to get the entire design into CAD before anything expensive is ordered, unlike last time where I did it the other way round! It was an expensive lesson, buying the engine first so I could design the car around it, but because the car wasn't done for 10 years the engine sat in the garage, depreciating the entire time - lesson learned. I already have my eye on a drivetrain, but it's too expensive right now, but hopefully after the design's all ready (maybe even after the chassis is designed) the price will have dropped.