11/27/12 OK... NOW. Enough of the almost, the nearly there, the little bit more. This is the last dry day for a while and all looks doable. We have a to-do list on a shop window written in dry erase marker and by mid-afternoon all of it is done.
There are a couple things we need to watch - for example the coolant hose clamps (of which there are a couple dozen) are not crimping as tight as they should. The specs are fine for the diameter of hose but reality is iffy. Sure enough, when the coolant is filled things start leaking. And daylight is already fading outside. We think about it for a minute but we have to move forward. So a trip to a parts store yields new clamps and they are all replaced. Coolant refilled, ready to try an engine start with the car up on jackstands.
Click of the switch, twitch of the starter and POP - a fuse blows. Simple wiring error on my part, easlity fixed. Fuse replaced, another attempt and VROOOMMMM - it's alive! Video here.
It's surprisingly quiet. Almost disappointingly so. But in these days of 90 db noise limits at trackdays that may not be a bad thing. Can always fit smaller mufflers, not always bigger ones. On the plus side the engine is VERY smooth and there is virtually no vibration transmitted to the frame, even though the engine doesn't move in its mounts. I seem to have gotten the mounting scheme right at least NVH-wise.
Now it's dark and we face a dilemma - do we call it a day and risk the weather tomorrow or do we just figure out a lighting scheme and go for it? We're only going up and down the block anyway and the benefit of the late hour in this neighborhood is that streets are pretty empty. The decision is 'no more delays!'. So we attach some lights, the car is rolled to the door and we're ready.
M goes outside with the ipad in camera mode to be the videographer and traffic spotter, Tristan hops in the passenger seat with a fire bottle (just in case) and the big moment is here.
The video of the occasion is on youtube. Even only using part throttle the car is a MONSTER :) To be sure there are a few things we need to tweak (throttle pedal linkage is one, I'm glad it's adjustable in our setup!). But overall as far as first drives go this is a good one. I've done a few of these now but I'm still genuinely excited. This car is going to be very cool when fully sorted. Exactly what I had in mind when I first started the project.
Now lots of fine tuning, adjustments, testing and so on. Besides those relatively minor items the next major thing to tackle is the bodywork. I'm not yet satisfied with the styling so I need to direct some effort towards that. This will go hand-in-hand with getting a baseline aero simulation in SolidWorks and evolving the form and function together. Should be fun! Also hoping to get an ORP outing this year still, the weather will be the determining factor there.
12/14/12 Haven't posted an update in a few days but we've been busy. The next major milestone is a track drive at ORP. The schedule is set by the first customer, Alex, who will fly out to drive his car. Currently we're shooting for Thursday the 20th. The weather is chilly (37F high 26F low at ORP) but there's a decent chance it won't snow and that's all we can ask for this time of year.
The bodywork is still in the process of being designed. In order to properly run air through the radiators (good idea even when it's cold) Tristan designed and fabricated some side scoops. Did a damned good job. Designed it in SolidWorks, made a flat pattern then fabricated by hand.
This closely approximates the eventual bodywork and will be a good initial test of the setup's effectiveness. Due to the cold we decided that the floor and side panels have to be on for this outing. So that's what Tristan has been working on for the last few days. The panels were laser cut but all the fitting, welding of brackets and trimming is a manual job.
Another update is for the steering - the new shorter steering arms came back from anodize and are now on the car. The ratio is some 45% faster now and feels much better.
As with all of my creations it's a good exercise to constantly remind oneself of the power that is packaged in such a small space. The pictures I post don't always give a good reference since I tend to leave people out of them, so here are a couple of M and Tristan trying the D2 on for size. That's 6.2 liters of V8 with 430 hp and 450 lb-ft of torque right behind them. The D2 weighs 1,650 lbs as it sits... and most people think that a 300hp, 3,400 lb car like a WRX STI is 'fast' ;)
12/19/12 The weather at ORP is snow and wind gusting to 30-50 mph. Not exactly a good setting for the first D2 track drive... bummer. So that will have to wait till January some time. Meanwhile I'm in the midst of updating a million design items and yes, the first batch of frames will still be ordered this Friday (which is why introductory pricing expires then).
There are some things that we're doing on the actual car - trimming the exhaust pipes to proper dimension is one item. There may be additional trimming when the bodywork is done.
Today we also got the Schroth DOT-approved 4-point belts which we have been planning to use as standard. Good idea in general but the seats and other constraints make it impossible in current configuration. So a re-think on the seats (we'll most likely do our own carbon ones, now that we have a good source for that) and the belt attachment is in order. Which cascades into subtle changes to the frame tubing. Which in turn is the reason for doing all of this now before we order a bunch of tubes. Everything is connected to everything else.
The next and ongoing item is the styling. If you browse the earlier pages you'll see the evolution, which has now in some ways come back to an earlier stage, modified. The picture below is just temporary and one of countless start-from-scratch versions that I've been kicking about. I do like the relative simplicity of it. Of course it's going to change from here but it sets a direction to follow.
Some may have spotted the change from quad headlights to dual - I'm contemplating using the Hella 90mm integrated DOT high/low units now. We'll see.
The details matter a lot. Things like how it will all fit together, be manufactured, assembled, serviced, painted, upgraded... And of course we'll have to make a plug and a mold for every body and trim panel which is a factor. A rough count indicates 16 molds right now and it's likely to increase. The D2 is definitely the most complex car we've tackled yet, in the manufacturing sense, although conceptually it's the most conventional.
Most of the bodywork will be built directly on the frame and molds pulled from that. This is in direct contrast to our previous cars which all had CNC machined plugs. We might still do a few CNC pieces here and there but for this type of car the direct approach is more efficient. Or so it seems right now. At any rate, January will be a composites/bodywork month and I actually look forward to spending time away from the computer and in the composites room getting hands (and everything in the vicinity) dirty.
01/03/13 The first post of the new year. Frame tubes have been ordered along with a number of other parts, hundreds more to order and make. We have our work cut out for us! :)
One of the things we have discovered in the process of test-fitting several people in the car is that the seats we had selected won't work due to belt routing. So we're back to making custom seats which isn't that big a deal, just one more thing to do. On the plus side it will result in a better looking and more functional interior.
Exterior styling is a major work item right now. Since we have the frame sitting here it's a good exercise to do some rough mock-ups with cardboard, just to see how the proportions work out in real life vs computer. Adam, one of our first customers, has volunteered to do that while I do the CAD equivalent. It has proven very useful and confirmed several things. Below are some pictures of the mockup progression and then the resulting CAD screen shots.
The first pass confirms that the nose piece is a rather large and chunky item that needs to be broken up visually....
Some black spray paint makes it look sleeker but still too much of a 'beak'.... A few more tweaks and it starts looking reasonably proportionate. There is also a natural place for the lights and even the front license plate (a rarity on sports cars).
So with everything learned, here's the current state of the styling:
Not final yet but close enough to where we can start prepping the chassis for the shapes to be built directly on it. This will be quicker and more cost-effective than CNC cutting the whole car although me may end up doing some individual panels that way.
It's a bit scary how much work we have to do but exciting also.
01/07/13 In the real world we've bought some foam and supplies to start building up the body on the frame. In the virtual domain, I've started on the CFD analysis to see if we need to make any last-minute changes and to get a feel of what to expect when it's all done.
In the past all the CFD work was done for us by others so this is my first attempt at doing it myself. I'm using SolidWorks Flow Simulation. Needless to say it's a very steep learning curve. Took me all weekend to figure out what parameters to set up and how, prep the model so that it works within the simulation and then extract the results I need. None of it is intuitive or documented in a directly accessible way. The tutorials that come with the program are oriented more towards figuring out how to cool integrated circuits in a computer enclosure than designing cars. All the functionality is there but you need to know what you want to do in order to be able to find it. A bit of chicken-and-egg. I suppose taking a class would help but that's not how I do things :)
So quite a bit of trial and error, a lot of educated guesses and a bit of searching on the web and I'm on my way.
As with any simulation, the quality of the results is very dependent on the details of the model and the setup. Making sure the mesh is adequate, constraints and limitations are reasonable and the model is complete enough while being simple enough for processing are all part of the prep.
Even so it is necessary to make reality checks and keep things in perspective. The program outputs results with 6 digits past the decimal whereas at this point in the process I'd be lucky to have them accurate within 10%. But it is still very useful.
What I've learned so far is that without wing or diffuser there's a bit of lift (to be expected). More interestingly it's mostly at the back. In retrospect it makes sense, there is very little area in the pointy nose to generate lift and it's generally shaped so that everything ahead of the windshield (other than front wheels/fenders) generates downforce. Consequently adding a diffuser is very helpful, as is adding a wing, and adding both is a lot better than just the sum of the two separately - again not surprising based on what I've learned with our other cars.
Too early to talk specific numbers but generally I'm pleased. There is a lot of optimization to be done, primarily on the aero bits. Overall the shape looks pretty decent for this type of car so we can proceed with the physical buildup while theoretical work continues.
01/10/13 This happens often - I get an idea of what a 'perfect' design or spec would be for a certain component and then frustratingly can't find it available so I have to make one, or at least get it made. I suppose ultimately Palatov Motorsport was born from this. Case in point here - dash and integral datalogger unit. There are many on the marked and we've used several with various degrees of success but none have the combination of function, price and reliability that I want. So again we're having it made.
Fortunately, this time I don't have to do it myself. Pete, one of our D2 lead customers, is the mastermind behind CMS Lap Timer. We used one of his devices on our Pikes Peak car and when the discussion came to what the dash is going to be on his D2, I asked if he'd be interested in developing one. Many more conversations followed and now it's an official project. The goal is to have the dash units installed on the current batch of D2s that is being built, scheduled for delivery early spring. Below are pictures of test-fitting two different screen sizes that we are considering.
The larger screen is attractive although it would be partially obscured by the smaller steering wheels (solved by using an open-top one or just putting data on the visible portion). It can also be center-mounted and that will be a good option for those who want to install the unit in a production car that already has a dash. To clarify, the system will only have one screen of either size not two.
In addition to a sunlight-readable full color display (programmable as to what is displayed and how) it will have data logging, lap timer and analysis capabilities with standard 3-axis accelerometers, 10hz GPS, analog, digital and OBDII inputs, shift lights, HD video and eventually even live telemetry to the pits (as an extra cost option).
A couple months of development are still ahead but it's looking promising. Yes the system will be availalbe for purchase without buying one of our cars. At this point we're targeting $1,200 MSRP for everything but that may change.
01/11/2013 In preparation for the bodywork we had to do a couple things. One is to wrap the frame and major components in tape and plastic so that bondo doesn't get permanently attached to them. The other is to mount the headlights. Tristan told me the lights were done minutes after I posted yesterday's update on the dash so they get their own update today.
The lights themselves are Hella halogen projector units. The adjustment is with shims where the assembly mounts to the frame and each light can also be shimmed relative to the mounting plate if need be. This is the standard light configuration but others are possibe by simply making a different mounting plate (and corresponding fairing).
Also we got word that the bent main tubes for the next 4 frames are done and we'll be getting them Monday. the rest of the tubing is not far behind. There's a sense of excitement and urgency in getting these cars built and out there - this is fun! :)