yep, the site is http://www.mulsannescorner.com/ and is a very cool compilaton of data, pictures and articles. a recommended and interesting read for the tech geeks among us. as with anything it should be taken as a refence but not necessarily the definitive source - for example the vortex generator expert that i've been talking to had some interesting comments on their article on vortex lift (no, don't ask).
some of the best LMP designs approach 5:1 L/D which i have no hope of achieving within my design goals (streetable rideheight, sane spring rates and no visible wings). i would be quite pleased with 1:1 and that looks achievable. anything better than that is a bonus. keep in mind i'm primarily building a trackday car, not not an outright racer (although the only thing stopping someone from racing it would be various rules and regulations).
one of the dangers of high downforce is that it's dependent on everything being just right and if for some reason that goes away even for a fraction of a second, the car can go from 4g cornering capability to under 2g in an instant. tough luck if you're in a 3.5g corner at the time. or you can get the flying mercedes at le mans.
my design goal is build a car that's outrageous but still reasonably accessible to a non-professonal driver (yes, those of us who are not natural talents but enjoy driving anyway
). this means emphasizing mechanical grip over aero and low-speed performance over high-speed perfomance. i don't care about going 200 mph because you will never see that at a trackday no matter what you're driving. i was hitting 175 on my yamaha r1 and that made me sell it - way too much for me to handle. 150 is about all i'd want in a trackday (ok, the dp1 will have a top speed of about 170 but i doubt it'd see more than 150 at most tracks). likewise, i'm getting 1.7g mechanical cornering (hopefully more to come) and it already is a huge leap of faith for most drivers (myself included) to go charging into a corner at those speeds. if the car were capable of 3 g due to downforce in reality that would never get used. so my primary goal with aerodynamics is stability and prevention of lift. drag is also not that bad a thing as long as you've got the power - it helps braking.
i generally like the top gear stuff - certainly refreshing at times if by nothing else than their general irreverence. that's why stereotype humor is a bit disappointing coming from them, but whatever. personally i i'm not generally offended by humor at others' expense, regardless of context - just makes me wonder why people say what they do and what that tells me about them 
and no i'm not claiming moral superiority here by any means - have certainly said and done my share of questionable things over the years
it's all in good fun and i'm cool with that. it's just sometimes amusing to take a step back and look at the why....
and no i'm not claiming moral superiority here by any means - have certainly said and done my share of questionable things over the years
it's all in good fun and i'm cool with that. it's just sometimes amusing to take a step back and look at the why....
i wish it were true - then he'd write me a check instead of being an annoying pest
surely there must be things funnier than bashing how other people choose to live (or drive)? unless it's a sorry attempt to make themselves feel better
i run into this occasionally as well - pretty ironic since we're really all europeans here, the REAL americans live on reservations. spain, france and england get full and exclusive credit for that.
i also run into people who jump to criticizing my driving based on the videos - some get into outright hysteria on the subject. their problem and their loss. first thing, my site exists to share my experiences (good and bad), not to make myself look good. i post videos when there is something of interest to share and typically that means something out of the norm. so it should not be a surprise to see mistakes in them.
yep, i do make mistakes. i'm not a 'natural talent' at driving but through a lot of practice and perseverance i've become fairly good at it. this is not boasting, just an objective evaluation based on lap times, comparing myself with other drivers, and opinions of experienced racers who have actually ridden with me on the track. i still have lots to learn and am in fact always learning. i expect (and hope) this will continue for some time. by the same token i have already learned a great deal and am only too happy to share this with anyone who is interested. driving is not magic, it's a skill that can be taught to a high level of competence (but brilliance does require talent, like with anything else). for example, all my students at trackdays are visibly better drivers after a day of my instruction and that's gratifying to me.
likewise i'm always happy to give rides at trackdays - no certificate needed
definitely in the mini at least - the atom will depend on insurance but that's just the harsh reality of it. and, on the subjec of reality, if anyone wants to DRIVE the dp1 in real life unfortunately i will require a 50% cash deposit (refundable). considering the performance potential anything less would be foolish on my part and finally, i'm not aware of having a fan club. but there is a guy who's been stalking me for about four years, prying into details of my personal life and discussing them on various forums. does that count? he's a vocal critic of my driving technique too
in regards to the segway - technologically it's an absolute marvel of engineeing. very cool stuff. in terms of usefulness, my personal opinion (and take it as such) is that it's misguided in its intent and was very overhyped (no surprise considering what they've spent developing it). Kamen's background is designing very cool (and hideously expensive) wheelchairs and so the segway is basically more of the same - a mobility device. except he tried to create a mobility device for people who don't need it. americans don't need to be saved from walking. even the mail carriers, who were envisioned as the big market, have overwhelmingly said they prefer to walk and that using the segway they get cold and sore. walking beats standing if you've got to be on your feet for a while. it might help senior citizens who live within a mile of a grocery store shop for groceries, that's about it.
if you take a step back and look at it objectively, you have a big, heavy, EXPENSIVE (read likely to be stolen) device that offers no protection from the element and doesn't have the range or the speed to be an alternative to a car (whereas a bicycle does, in many cases and is vastly simpler, cheaper, lighter and easier to store and secure). segway is not usefully faster than walking, can't be carried onto public transportation, needs ramps to be loaded into a car if you want to take it somewhere and takes up a bunch of space wherever it sits. but at least it's expensive
so yeah, i think the intentions were noble but naiive, the technology is amazing, the amount of money spent to bring it to market is obscene. overall i'd have to concur - pretty useless.
again, just an opinion.
if you take a step back and look at it objectively, you have a big, heavy, EXPENSIVE (read likely to be stolen) device that offers no protection from the element and doesn't have the range or the speed to be an alternative to a car (whereas a bicycle does, in many cases and is vastly simpler, cheaper, lighter and easier to store and secure). segway is not usefully faster than walking, can't be carried onto public transportation, needs ramps to be loaded into a car if you want to take it somewhere and takes up a bunch of space wherever it sits. but at least it's expensive
so yeah, i think the intentions were noble but naiive, the technology is amazing, the amount of money spent to bring it to market is obscene. overall i'd have to concur - pretty useless.
again, just an opinion.
yes, eventually it'll get painted but that's a ways down on the priority list. graphics will definitely happen though, i just need to get it done.
i've driven a couple mitsu EVOs on the track - an EVO VI Makinen (a private import, that's before they were legal here) on R tires and an EVO VIII on street rubber. both were quite fun, Makinen especially. EVOs are set up to drift around corners and they do it very well. you can do loooong controlled powerslides, just pitch it in with a flick of the wheel and then opposite lock and steer on the throttle. i almost bought an EVO actually but then decided the mini was more my style.
also drove a student's 996 C4 on street tires - big, fat and soft. didn't care for it much.
the dp1 proto doesn't really behave like an awd car. it's pretty neutral, very steerable with throttle (lift and the tail rotates, push and the nose runs a little wide but nothing you'd call understeer). you can apply power very early in turns, much earlier than i've been doing so far.
of course the production drivetrain is different, replacing the prototype's quaife center diff with a proprietary setup so we'll see how that behaves.
i've driven a couple mitsu EVOs on the track - an EVO VI Makinen (a private import, that's before they were legal here) on R tires and an EVO VIII on street rubber. both were quite fun, Makinen especially. EVOs are set up to drift around corners and they do it very well. you can do loooong controlled powerslides, just pitch it in with a flick of the wheel and then opposite lock and steer on the throttle. i almost bought an EVO actually but then decided the mini was more my style.
also drove a student's 996 C4 on street tires - big, fat and soft. didn't care for it much.
the dp1 proto doesn't really behave like an awd car. it's pretty neutral, very steerable with throttle (lift and the tail rotates, push and the nose runs a little wide but nothing you'd call understeer). you can apply power very early in turns, much earlier than i've been doing so far.
of course the production drivetrain is different, replacing the prototype's quaife center diff with a proprietary setup so we'll see how that behaves.
i haven't had much luck playing with photoworks and it really hasn't been a priority lately. i know it can be done but too much work remains on actually getting the car finished. thank you for the rendering offer but i'm sure you'll understand that i'm not too keen on sending the database out. anyway, the complete assembly is over 450M in size last time i checked... so bottom line is that rendered pix will have to wait but there should be some more photos when testing resumes in month or so.
very impressive. again, i'm in awe. i know just enough about it to know what it took and my hat is off.
and yes, that's about right for tire (tyre) behavior
http://www.dpcars.net/scion/sc050l.jpg
the car is very wide and the driver sits fairly close to centerline. with 185 lb driver the balance is about dead even, so 50 lbs difference in either direcion will have very minimal effect on balance. basically adding 50 lbs in the driver seat adds about 33 lbs on the left side and 17 lbs on the right, so if you started with let's say 525 lbs left and 525 right with 185 lb driver, you'd end up with 558 and 542 with a 235 lb guy behind the wheel (likely won't be a girl!
) which is still pretty damned close (only 0.7% left-heavy). maybe schumacher can tell that kind of difference but i know i won't be able to.very cool! the fact that it's all being done in realtime is mindboggling really. i've been in computers for almost three decades now and what i was trying to do with 3D graphics on the university's mainframe back in '82 is cave drawing in comparison. having a detailed appreciation for both the hardware and the software necessary to make it happen just leaves me in awe. these are good times to live in
i'll work on getting some better pix as things progress but it'll take some time.
here's one in 1600x1200 http://www.dpcars.net/dp1/img005.jpg
if you go to http://www.dpcars.net/dp1 and click on 'media', at the bottom there are a few thumbnails for relatively high-res pix, some more so than others. just click on each one
if you go to http://www.dpcars.net/dp1 and click on 'media', at the bottom there are a few thumbnails for relatively high-res pix, some more so than others. just click on each one
i was going back and forth on the louvers. the basic idea was to do the whole body as one piece. that way there's only one mold and one layup so in theory it saves cost and weight (the entire body is just 41 lbs). in a way by incrporating them into the main bodywork they're 'free' whereas as separate panels there'd be an extra four molds and extra four parts to make, plus all the trimming to make the seams clean and straight. panel fit problems were a major thing i was trying to avoid with the one-piece design.
but there are definitely drawbacks to this, primarily having to do with repair and replacement. it's all a learning experence. as time goes on i'll probably modify molds and make new ones but it's not the highest priority right now.
as for the frame, the prototype's frame is skinned with structural aluminum panels which is both stiffer and lighter than tube triangulation (the official term for it is semi-monocoque, it was used in some can-am cars and formula cars of the era). the production chassis will be a carbon tub. on an f1 car the chassis takes up an even smaller portion of the car's width
but there are definitely drawbacks to this, primarily having to do with repair and replacement. it's all a learning experence. as time goes on i'll probably modify molds and make new ones but it's not the highest priority right now.
as for the frame, the prototype's frame is skinned with structural aluminum panels which is both stiffer and lighter than tube triangulation (the official term for it is semi-monocoque, it was used in some can-am cars and formula cars of the era). the production chassis will be a carbon tub. on an f1 car the chassis takes up an even smaller portion of the car's width
sounds fun, doesn't it?
no prob, it's fair game
it's very difficult to plan something when you don't know what you're up against yet. too many variables. even when you've been down the development path a few times you can still really only set targets and have contingencies, rather than actual plans. that's why new product delays are routine, even from companies sitting on a few billion in cash given that this is my first car design (i'm a software geek by education) and factoring in the fact that i have to rely on outside vendors and also somehow pay the bills, there is a big variance on when things actually get done. yes, it was technically feasible to get it done in under two years. but i'm still pretty happy with five. the important thing is not to give up and to keep moving forward. there are some products where if you miss the window it's yesterday's news. something like the dp1 will be relevant for a while to come and i have big plans for follow-on projects
it's very difficult to plan something when you don't know what you're up against yet. too many variables. even when you've been down the development path a few times you can still really only set targets and have contingencies, rather than actual plans. that's why new product delays are routine, even from companies sitting on a few billion in cash
given that this is my first car design (i'm a software geek by education) and factoring in the fact that i have to rely on outside vendors and also somehow pay the bills, there is a big variance on when things actually get done. yes, it was technically feasible to get it done in under two years. but i'm still pretty happy with five. the important thing is not to give up and to keep moving forward. there are some products where if you miss the window it's yesterday's news. something like the dp1 will be relevant for a while to come and i have big plans for follow-on projects i hope you can come out - it's a lot of fun (but be warned, it's addictive!)
only requirement is that you will need your own helmet and it should be SA2000 or SA2005 rated (some clubs accept motorcycle M rated helmets but many don't).
for alfa day just show up at the gates at 7:30 am (there is no preregistration). for porsche and bmw (and some others) you have to pre-register and those event fill up early, especially in novice group. there is club contact info on PIR site, you can get in touch with each club directly for details.
only requirement is that you will need your own helmet and it should be SA2000 or SA2005 rated (some clubs accept motorcycle M rated helmets but many don't).
for alfa day just show up at the gates at 7:30 am (there is no preregistration). for porsche and bmw (and some others) you have to pre-register and those event fill up early, especially in novice group. there is club contact info on PIR site, you can get in touch with each club directly for details.
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Bob, that pretty much matches my own calcs the actual gear ratios are:
2.42
1.71
1.3
1.08
0.92
final drive is 3.889. tires are 225/45-13 (20" OD). a fixed torque split is a reasonably good way to model the driveline.
Micaoct, you can run with any club. all brands are welcome and every club has a novice run group and provides instructors (i instruct for porsche, bmw and lotus clubs). some require you to join but you can do it on the spot. costs range from $125-175 for the day depending on the club and whether you're a member. typically that gets you about 100-140 miles of on-track driving. the schedule is at http://www.portlandraceway.com i'll be at the alfa day on march 24. what car(s) i bring will depend on weather and how much i get done by then
the actual gear ratios are:2.42
1.71
1.3
1.08
0.92
final drive is 3.889. tires are 225/45-13 (20" OD). a fixed torque split is a reasonably good way to model the driveline.
Micaoct, you can run with any club. all brands are welcome and every club has a novice run group and provides instructors (i instruct for porsche, bmw and lotus clubs). some require you to join but you can do it on the spot. costs range from $125-175 for the day depending on the club and whether you're a member. typically that gets you about 100-140 miles of on-track driving. the schedule is at http://www.portlandraceway.com i'll be at the alfa day on march 24. what car(s) i bring will depend on weather and how much i get done by then
PIR is a city park (it's owned by the city of portland) so it's pretty likely there won't be a problem if there is desire to add the track. next month i'll be talking to the guy who runs it (in regards to dp1 testing) and can mention the possibility if you like.
on the subject of PIR - the track is under attack by some people at city hall and now there is an organization formed to protect it. we are looking for more members (there's strength in numbers when it comes to politics!) so if some of you would join it would be awesome - there is no cost and you won't be spammed. http://www.friendsofpir.com
i too am impressed (and honored) by the support shown by the lfs community for the inclusion of dp1. actually one of the greatest benefits i've found in sharing my development process with the world is that people get interested and sometimes offer to contribute. for example all the various CFD runs were done for me by several different people who just wanted to be a part of the project and to learn something in the process.
project bikini is my v8 ariel atom - http://www.dpcars.net/atom.htm
one thing that makes it easier is that there is virtually no elevation change (about 5 feet, literally). there ARE some subtle off-cambers that make driving it a lot trickier than one would think. they make the car do things you wouldn't expect and leave you wondering 'wtf was THAT?'. running a bike there makes you wonder even more. it took a couple track walks for me to figure it out. so if anyone is actually going to try and build it, email me through [email protected] and i'll be happy to share whatever i know.
dp1 proto vs bikini will actualy be a very interesting comparison. i'm very curious to see the outcome myself. dp1 proto has decent power/weight (about 5 lb/hp), bikini is significantly better at about 3 lb/hp. of course it'll be very traction-limited. but power/drag of the dp1 proto is not what i'd want. i can definitely feel acceleration diminishing at 120 mph but of course i wasn't using all of the power either (short-shifting at 8K). straightline speed feels subjectively only a little better than a 245hp atom so a 400hp one would probably prevail there. cornering-wise dp1 is much better than the atom. others have recorded a peak of about 1.3g in their atoms on r compounds, which is roughly the same as the elise (makes sense). dp1 is closer to 1.7-1.8g on same tires so i think that will be a big factor because a lot of time at PIR is spent in the turns despite the long straights. this is down to much lower cg, wide track, almost no roll, better camber control, more tire and 30% less weight.
my rough guess, the dp1 proto should get into mid-to-high teens (i.e. 1:15-1:17) wherease bikini will stay in the low 20's (1:21-1:23). when both are fully sorted and when i'm calibrated for the speed, that is. the first few trackdays of the year will be far short of that. actually in the first dp1 proto outing my goal was 1:35 and i managed to just get under 1:30 with only two clear laps in the whole day, so it's encouraginig. and this was taking turn 10 7mph slower than i do in the mini
for reference, 1:15 is a typical ALMS GT2 race lap at PIR.
it will definitely be a year of much learning. stay tuned
my rough guess, the dp1 proto should get into mid-to-high teens (i.e. 1:15-1:17) wherease bikini will stay in the low 20's (1:21-1:23). when both are fully sorted and when i'm calibrated for the speed, that is. the first few trackdays of the year will be far short of that. actually in the first dp1 proto outing my goal was 1:35 and i managed to just get under 1:30 with only two clear laps in the whole day, so it's encouraginig. and this was taking turn 10 7mph slower than i do in the mini
for reference, 1:15 is a typical ALMS GT2 race lap at PIR.
it will definitely be a year of much learning. stay tuned
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to try LFS i'd want at least a steering wheel and preferably pedals too. i'll get around to getting a set (been meaning to for some time now) but right now a lot of projects are taking up time and energy. if the devs decide to include the dp1 in the sim then this would definitely get bumped up in priority
and yes, playing with cars, motorcycles and such takes a high priority for me because it's something that i truly enjoy. as for funding dp1 it's basically a field-of-dreams thing looked at as a matter of priorites, it's actually cheaper than putting a kid through 4 years of private college and LOTS of people manage that. i choose not to have chilren, therefore i can put the resources towards the only kid in my life - myself
and yes, playing with cars, motorcycles and such takes a high priority for me because it's something that i truly enjoy. as for funding dp1 it's basically a field-of-dreams thing
looked at as a matter of priorites, it's actually cheaper than putting a kid through 4 years of private college and LOTS of people manage that. i choose not to have chilren, therefore i can put the resources towards the only kid in my life - myself
Last edited by dpcars, .
i was also thinking the same thing. would make a lot of sense as a third license level maybe? hope the devs give some thought to it, i'm guessing there's a large and growing market for something like that (if done right).
google earth should make creating accurate real tracks feasible. just have to know the town the track is near and you can find an accurate picture. here is one of the pats acres kart track, for example...
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Reason : addition
the purpose for the prototype testing is to learn - there are many novel solutions in the car so its dynamics are an unknown. first few tests have shown that some things work and others don't, i'm sure there are many more discoveries in store. at the time of first PIR test the car had about 50 miles on it and the engine about 80 miles. during the testinig i have to strike a balance between pushing hard enough to properly exercise various functions but not so hard that i break things. considering that there is only one prototype in existence and how much i have invested in it, i will continue to do the testing methodically, at my own pace. yes, pushing harder is part of the program but i will choose when and where. dragstrip testing won't happen until i have a pre-production car built and sorted so probably late summer at the earliest.
in some ways, if LFS physics are accurate enough, having the car in the sim might prove a useful development tool as well. or at least, with real-life testing proceeding in parallel, we could see how well things correlate. maybe the devs will include PIR as one of the tracks?
speaking of correlation, did anyone see the top gear bit on clarkson driving an nsx at laguna seca, first on playstation and then in real life? i can't fnd the video on utube now because it's been removed due to terms of use violation. but basically he's something like 10-15 seconds slower in real life than in the game
and finally, to give some ida of what the prototype with 180hp should be eventually capable of (when fully sorted and on slicks), you can watch this video http://www.dpcars.net/larry.mpg of my friend larry at PIR in his DSR. the car weighs same as the dp1 and is powered by a 180hp motorcycle engine. larry has run 1:09 at PIR with that car (the factory R10 qualified at around 1:05). the lap in the video is 1:13 and the video doesn't do it justice but it's the only one i have. that kind of pace i'll definitely need to work up to, won't be happening this year. biggest challenge is carrying speed into corners - it's a major commitment to drive into a corner knowing you'll need 2g to make it through and that you'll be hitting the wall at 80+mph if you don't make it.
in some ways, if LFS physics are accurate enough, having the car in the sim might prove a useful development tool as well. or at least, with real-life testing proceeding in parallel, we could see how well things correlate. maybe the devs will include PIR as one of the tracks?
speaking of correlation, did anyone see the top gear bit on clarkson driving an nsx at laguna seca, first on playstation and then in real life? i can't fnd the video on utube now because it's been removed due to terms of use violation. but basically he's something like 10-15 seconds slower in real life than in the game
and finally, to give some ida of what the prototype with 180hp should be eventually capable of (when fully sorted and on slicks), you can watch this video http://www.dpcars.net/larry.mpg of my friend larry at PIR in his DSR. the car weighs same as the dp1 and is powered by a 180hp motorcycle engine. larry has run 1:09 at PIR with that car (the factory R10 qualified at around 1:05). the lap in the video is 1:13 and the video doesn't do it justice but it's the only one i have. that kind of pace i'll definitely need to work up to, won't be happening this year. biggest challenge is carrying speed into corners - it's a major commitment to drive into a corner knowing you'll need 2g to make it through and that you'll be hitting the wall at 80+mph if you don't make it.
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