Digsy Posted August 18, 2005 Share Posted August 18, 2005 Did the search, but cannot find anything. What is the Supra's frontal area? Link to comment Share on other sites More sharing options...
merckx Posted August 18, 2005 Share Posted August 18, 2005 I'm not sure if anyone understands the question, I didn't! Link to comment Share on other sites More sharing options...
Matt Harwood Posted August 18, 2005 Share Posted August 18, 2005 The bit in front of the windscreen Link to comment Share on other sites More sharing options...
Mike Posted August 18, 2005 Share Posted August 18, 2005 Thinking of Lobotomising? Link to comment Share on other sites More sharing options...
Digsy Posted August 18, 2005 Author Share Posted August 18, 2005 Oh, you comedians you. Imagine you could put a projection screen on front of a Supra and then shine a light on it from behind. The area of the shaow it cast would be the frontal area. Its essential to know this (and the Cd) if you are trying to work out power figures from vehicle speeds. I have a figure of 1.98m^2, but that seems a bit low. Link to comment Share on other sites More sharing options...
Soonto_HAS_soop Posted August 18, 2005 Share Posted August 18, 2005 Isn't the Cd 0.32 with rear spoiler, and 0.29 without? Not 100% sure of the frontal area though, will check later (when not at work) Link to comment Share on other sites More sharing options...
Guest Terry S Posted August 18, 2005 Share Posted August 18, 2005 Oh, you comedians you. Imagine you could put a projection screen on front of a Supra and then shine a light on it from behind. The area of the shaow it cast would be the frontal area. Its essential to know this (and the Cd) if you are trying to work out power figures from vehicle speeds. I have a figure of 1.98m^2, but that seems a bit low. What height is the projector, surely that will effect the shadow cast Link to comment Share on other sites More sharing options...
Digsy Posted August 18, 2005 Author Share Posted August 18, 2005 What height is the projector, surely that will effect the shadow cast :baa: Link to comment Share on other sites More sharing options...
Nic Posted August 18, 2005 Share Posted August 18, 2005 SupraStar 3000 posted full scale front, side, plan images of the Supra a week or so ago, perhaps you can use that to work out the frontal area. Link to comment Share on other sites More sharing options...
Nic Posted August 18, 2005 Share Posted August 18, 2005 See [thread=44129]THIS THREAD[/thread] Link to comment Share on other sites More sharing options...
merckx Posted August 18, 2005 Share Posted August 18, 2005 If you're trying to work out power figures for modified cars using their speeds you could start by getting the figures for a stock car. Get the average figures for a stock car , bhp and speed and put them in your equations and work backwards to get a constant which will be your frontal area and drag factor combined. Cannot think of any reason why this won't work to give you approximate power figures. I'm not too sure if it would be easy to do it that accurately, It wouldn't be simple working from first principles as there would be other unknowns such as car weight and varying tyre sizes resulting in increased rolling resistance and drag . Link to comment Share on other sites More sharing options...
CJ Posted August 18, 2005 Share Posted August 18, 2005 Digsy...you really need to get out more my friend Link to comment Share on other sites More sharing options...
Digsy Posted August 18, 2005 Author Share Posted August 18, 2005 Funny you should say that CJ. Have a look in the "thread killed at birth" thing in Off Topic and then try to believe I posted before I read your reply Anyway, its people like me who give you crazy kids fast cars to play with so don't knock it! Link to comment Share on other sites More sharing options...
CJ Posted August 18, 2005 Share Posted August 18, 2005 Funny you should say that CJ. Have a look in the "thread killed at birth" thing in Off Topic and then try to believe I posted before I read your reply Just read it - brilliantly coincidental eh? Link to comment Share on other sites More sharing options...
Digsy Posted August 18, 2005 Author Share Posted August 18, 2005 What can I say? Great minds think alike. Link to comment Share on other sites More sharing options...
TLicense Posted August 19, 2005 Share Posted August 19, 2005 Anyway, its people like me who give you crazy kids fast cars to play with so don't knock it! But I thought you worked for Lotus? Link to comment Share on other sites More sharing options...
Digsy Posted August 19, 2005 Author Share Posted August 19, 2005 Hardy-har har I'm goint to have to measure this for myself, aren't I? Link to comment Share on other sites More sharing options...
Guest Terry S Posted August 19, 2005 Share Posted August 19, 2005 Hardy-har har I'm goint to have to measure this for myself, aren't I? Yep, skip the pub tonight Link to comment Share on other sites More sharing options...
Digsy Posted August 19, 2005 Author Share Posted August 19, 2005 FFS. I'll think twice before asking a technical question in the technical section again, I can tell you. Link to comment Share on other sites More sharing options...
JohnA Posted August 23, 2005 Share Posted August 23, 2005 Any news on this Digsy? I would be interested myself, as I am using an aerodynamic drag approximation for 'on the road' power measurements. Link to comment Share on other sites More sharing options...
Digsy Posted August 23, 2005 Author Share Posted August 23, 2005 Any news on this Digsy? I would be interested myself, as I am using an aerodynamic drag approximation for 'on the road' power measurements. I'm doing the same thing. When I get off my bum and go ouside with my tape measure, I'll post up a rough figure. Alternatively, if someone could post up an "overall" dimension (like wheelbase, or width excluding mirrors or something) I'll scale it off the three-view that someone posted up a few weeks back. Link to comment Share on other sites More sharing options...
JohnA Posted August 23, 2005 Share Posted August 23, 2005 Sometime this evening I'll have my approx aero-drag figure (Cd x frontal) I've also got a rolling resistance approximation. Using the above and the vehicle weight, an accelerometer can figure out the max power produced during a run. Not sure how it will compare to RR figures, but I doubt that it will be more bull, and at least the car will be loading as it's meant to, with airflow through the SMIC and the engine bay as it is meant to be in real life. Obviously there will be no alt/temp correction and no graph thoughout the revs (not in my current version) but for assessing the effectiveness of modifications the max figure is good enough. Only good on dry, windless days though --- but hey, it's relatively easy, quick and free! Link to comment Share on other sites More sharing options...
Digsy Posted August 23, 2005 Author Share Posted August 23, 2005 Only good on dry, windless days though --- but hey, it's relatively easy, quick and free!It's also bloody hard to correlate. I started working on this a few days ago after I got some usable results from the RR versus 1/4 mile timeslips survey. I have 5 sets of results to work from. Assuming a 3m^2 frontal area, the best correlation I have so far is from Jake's results, which are practically spot on, although this will change when I plug in a real figure for frontal area.Jake.zip Link to comment Share on other sites More sharing options...
JohnA Posted August 23, 2005 Share Posted August 23, 2005 Have a look here. It does the calculations I mentioned before. It's the accelerometer I'm using. Link to comment Share on other sites More sharing options...
Ian C Posted August 23, 2005 Share Posted August 23, 2005 3m2 is a little low an estimate for Jake's frontal area isn't it? -Ian Link to comment Share on other sites More sharing options...
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