OlderThanMe Posted November 18, 2006 Share Posted November 18, 2006 OHHH... I see. I thought the chassis would only be kept in place from forward/sideways motion and free to move vertically but that makes more sense. Quote Link to comment Share on other sites More sharing options...
Royal Flush Posted November 18, 2006 Share Posted November 18, 2006 Haha! January 20th is my B-Day That'd be a nice gift Quote Link to comment Share on other sites More sharing options...
Mayolives Posted November 18, 2006 Share Posted November 18, 2006 As some of you know, I'm very interesting in helping to make this Wind Tunnel test happen. If well planned, it could provide extremely valuable information for all of us. I would ask that all interested parties provide thier input, parts to be tested and dollars to support this effort. Let keep this thread going! Quote Link to comment Share on other sites More sharing options...
Twoeightnine Posted November 22, 2006 Share Posted November 22, 2006 And there is this one. Should be mounted as far back as possible? http://forums.hybridz.org/attachment.php?attachmentid=1431&d=1160027867 Hey, me like. I saw that one on a s31 thats out in the parking lot right now. Looks like they mount to the s30 as well. Ok...who sells them? Quote Link to comment Share on other sites More sharing options...
jt1 Posted November 23, 2006 Share Posted November 23, 2006 Wow. I quit looking at the thread when it became a pissing contest, i just checked in to see how the urine was flying. Lot's of good thoughts here. I'll be glad to help out on the tests and contribute financially. My college roomie is an AE and a VG guru, I'll see if I can bounce some of this off him. Last time I tried to contact him, he was bouncing around Iraq in a F-16. I've also got the whaletail mikelly is referring to, we can use it to test if so desired. John Quote Link to comment Share on other sites More sharing options...
A. G. Olphart Posted November 23, 2006 Share Posted November 23, 2006 Rear spoilers seem to be a crutch to try and kill the Z's nice wing shaped roof and deck line... Might it not be more effective to use a variant of the Pantera style deck lid? This one has angled sides: http://album.hybridz.org/data/502/ZcarPanteraHatchDimensions.jpg I've been considering vertical sides and a slight (5 or 6 degree?) downward slope towards the rear, everything edged by the hatch glass opening. Perhaps a 1 inch mini spoiler at the top? Would a regular a spoiler then help join turbulent deck lid air with the turbulent air behind the car? These are questions I would like to see answered in the wind tunnel. I'm curious about $100 worth. (Hopefully someone has a parts car deck lid or two to play with back East, as shipping oversized items is pricey). <> Quote Link to comment Share on other sites More sharing options...
Mikelly Posted November 23, 2006 Share Posted November 23, 2006 BJ, When you get a tally running for donations, keep me posted on the amounts you need. As it gets closer to "GO/NO GO" I'll see what I can kick in to assist in making it happen... You can officially put me in for $100 as of right now, but if we get more traction on this and it gets closer to reality, I may be able to kick in as much as $500. Right now I'm starting to buy up parts for my own car as it comes together, so recreational funds are starting to dwindle weekly. Mike Quote Link to comment Share on other sites More sharing options...
bjhines Posted November 24, 2006 Share Posted November 24, 2006 I have several rear decks that I can modify for this experiment... I was thinking of cutting one up and making a steel "pantera" style hatch... I might reinforce it for a ricer wing as well... There are several other options on the table as well... We may try to find time to get a total of 3 cars in there... one demo dog... and 2 very different race style bodies... My biggest fear is that we find out that it will take a lot more than just one day at the wind tunnel to get real scientific data... I am hoping we can satisfy people with enough data to warrant a few hundred dollars spent... I need some fabrication time to get ready for this... that is hard to come by... but I look at this as part of my V-8 track car buildup... just more money and time spent... I don't feel too bad putting the rest of the project on hold to really dig into bodywork right now... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 24, 2006 Share Posted November 24, 2006 My biggest fear is that we find out that it will take a lot more than just one day at the wind tunnel to get real scientific data... I am hoping we can satisfy people with enough data to warrant a few hundred dollars spent... Yeah, this seems like the biggest problem. If this money can buy more time in the tunnel, that seems like it would be better than using it to buy a bunch of parts which you won't get to test due to time constraints. Can you buy more time? Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted November 25, 2006 Share Posted November 25, 2006 if you have the spare time(which you won't) try this type of wing... Quote Link to comment Share on other sites More sharing options...
A. G. Olphart Posted November 25, 2006 Share Posted November 25, 2006 BJ, the 'several rear hatches' approach sounds good. Four bolts per change seems simpler than fitting spoilers while on the clock. Demo dog should generate significant interest here on HybidZ... I'd like to see a stock configuration baseline run, but if fitting a front spoiler is too time intensive, might that have to be a given? How are the numbers derived? Do the four mounting posts register force in all directions, providing directly comparable info for a set/given wind speed? As I won't have to ship a deck lid, I may be able to kick in a bit more, but I'm not a major player. <> Quote Link to comment Share on other sites More sharing options...
primadonna z Posted December 1, 2006 Share Posted December 1, 2006 Depending on when. I could bring a g nose widebody, if there was interest. Quote Link to comment Share on other sites More sharing options...
240hoke Posted December 6, 2006 Share Posted December 6, 2006 Lemme know when you are doing testing!!! that tunnel is jsut a couple mintues from my house. Maybe we could have a little get together. Quote Link to comment Share on other sites More sharing options...
frank280zx Posted December 6, 2006 Share Posted December 6, 2006 if you have the spare time(which you won't) try this type of wing... downright sexy! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 15, 2006 Share Posted December 15, 2006 Moved from another thread: Hi David:As I understand it - the Kamm back design used on the First Generation Z's has the effect of forming a turbulent high pressure area at the end of the car. That high pressure area is what forces exhaust gases into the passenger cabin' date=' when the rear of the car isn't properly sealed. When you roll your windows down, that exhaust smell gets worse. (the opposite of what you would expect) That is because the high speed airflow along the sides of the car create a low pressure area, that is, lower pressure than that in the cabin. So when you roll the windows down - while outside air is forced in and circulates with the passenger cabin - cabin air also actually gets sucked out the side windows. Somewhat the same effect as air flowing over the top of a chimney (heat alone doesn't push smoke up a 20' chimney - ie, Venturi effect). Roll the windows up, and open the Z's Fresh Air Vents in the front of the car - and the exhaust smell gets better (ever so slightly)... because the forced air induction from the front of the car is now creating a slightly higher cabin pressure, but still not higher than the area behind the car... Add a rear spoiler and the exhaust smell is greatly reduced. That is because the effect of the Kamm back's turbulent high pressure area is effectively moved farther rearward, and the exhaust gases are no longer held as tightly against the rear of the car. The pressure differential between that high pressure area behind the car and the lower pressure area within the passenger's cabin, is not as great as it was before the rear spoiler was added. FWIW, Carl B.[/quote'] Hi Carl. Welcome. I have to take issue with this' date=' I don't think it is right. The turbulence in back of the car is not high pressure turbulence. It's LOW pressure turbulence. The reason the exhaust gets into the cabin is because it is SUCKED in, not PUSHED in. Flow separation, the cause of the turbulence, creates low pressure. Cracking the windows creates suction inside the cabin via the Bernoulli effect, so now you have suction inside the cabin and vacuum at the rear of the car, and that REALLY sucks the exhaust into the cabin. Any little hole allows air back in, and since that air is turbulating all the exhaust, that's what gets sucked into the cabin. I do agree that opening the fresh air vents increases the cabin pressure, and that works against the vacuum which is trying to force air into the holes in the rear of the car. That is why positive pressure works. I am not an expert, I only know what I've read here and elsewhere, but the bottom line for me is that you need some sort of deflector or barrier to create positive pressure, like air hitting the radiator, the windshield, or a spoiler. Just pulling the car through the air creates a negative pressure behind. Why can't you run fast in a swimming pool? Because when you try to move you create a huge turbulent vacuum behind you, and that tries to suck you backwards. Same thing with a car through the air, just a less viscous medium. If you created positive pressure behind, then you'd actually go faster for having it there. We worry about drag, but not about "push".[/quote'] Hi Jon: Thanks for the welcome and the response. This is a good discussion to have' date=' before the wind tunnel is cranked up, and indeed I could be conceptualizing all this in the wrong manor. How I understood it which could very well be the wrong way of thinking about it) "It" being the Kamm back design and its effects: I believe that Dr. Kamm did indeed worry about both Drag and "push". Yes, the tumbling/spinning air flow - ie. rotating in a horizontal circle, is moving at a higher speed, than the air flow coming off the car and transiting over the top of that circulation. The speed of the circulating air also gets higher as it approaches the center of circulation - and thus the center of that rotation is the lowest pressure area within that circulation. The center of a Hurricane is its lowest pressure area. But when Hurricanes come ashore - the circulating bands blow with very high wind speeds.. and thus exert very high pressures on anything they encounter (a mass of air molecules moving at very high speed). The high pressure area at the rear of the car in this case, is not the center of that circulation (low pressure area), but rather is at the point where the higher speed winds of that spinning circulation - strike/collide with (push against) the rear of the car. Just as the air striking the front of the car creates high pressure. As I understood it (that qualifier again) - Dr. Kamm wanted that center of circulation positioned at a point behind the car, to not only take advantage of its ability to effectively reduce separation turbulence (support a smoother transition of the air flow off the back of the car - much the same as extending the body itself back to a pointed end), but to also take advantage of the energy in that spinning low pressure area - and apply it to the back of the car - yes to gain a little offsetting "push". Adding the Nissan/BRE rear spoiler - effectively moves the center of circulation rearward away from the back of the car, and thus reduces or eliminates the high speed winds in the circulation from hitting the back of the car. I think "suction" is a term that describes an effect, I don't see how it can be a cause. Maybe if we're lucky we'll get a physics major upset enough to jump in here, as we mangle the subject. At any rate - If the pressure sensors are put in the right places on this project - we should be able to see more clearly just what is happening. FWIW, Carl B.[/quote'] Well I couldn't figure out how to move the posts directly, but I quoted them so that we could continue the discussion. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 15, 2006 Share Posted December 15, 2006 Another oversimplification of this drag phenomenon is that the car "tears a hole" in the air. I do not believe that the air rushing in to fill the hole creates a positive pressure, in much the same way that the air that rushes into your vacuum cleaner does not create positive pressure. I think you'll find that ANY aerodynamics engineer is going to try to keep the hole that the car tears through the air as far behind the car as possible, as Kamm had done. The less low pressure there is at the back of the car the less drag there is as it goes down the road. This is also why diffusers are so popular in racing cars. They are an attempt to bring air from underneath the car into the vacuum created as air flows over the top of the car, and lessen the size of the hole created. The closer one can get the wing or spoiler to the diffuser, the better. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted December 15, 2006 Share Posted December 15, 2006 The OUTSIDE of a vortex is where the air is travelling fastest, and thus has the lowest pressure. Your argument sounds logical to me Jon, and now I'm going to go and argue about vorticies and flow separation in this thread http://forums.hybridz.org/showthread.php?t=117165&page=2 Dave Quote Link to comment Share on other sites More sharing options...
speeder Posted December 17, 2006 Share Posted December 17, 2006 I might reinforce it for a ricer wing as well... What if the ricer wing is the best? Quote Link to comment Share on other sites More sharing options...
Sparky Posted December 17, 2006 Share Posted December 17, 2006 What if the ricer wing is the best? Then we will pretend the whole thing never happened. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 17, 2006 Share Posted December 17, 2006 It wouldn't be very ricey if it actually worked. For what it's worth the Mustang that I used to beat up on at the track (I was 5+ seconds faster last time we were both out @ Buttonwillow in 2000) is now posting times a full 10 seconds faster than my old times, and it now has a big ol wing on the back, and I'm pretty sure it's faster than John Coffey's ROD too. 10 seconds and faster than the ROD makes me think I could deal with the embarrassment of having a big ol wing on the back of my Z. Of course the wing is an actual racing part and is ~$1000, not a Wings West special... Quote Link to comment Share on other sites More sharing options...
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