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Old 06-21-2006, 02:42 PM   #76
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Quote:
Originally Posted by dsrbltoys
I just had a chance to catch up on what you are doing. We did some wind table testing some years back with a selection of tamiya bodies, a pair of digital scales in a platform table, and a large industrial floor fan. We found the weight of the front and rear of each car with body, without the fan on. Then turn on the fan to low about 15 mph, and recorded the weight of the car, and turned to high about 30 mph, and recorded the weight again. I see in your results you show you have downforce on the front of your body. We never actually saw this. We believe it was because of the shape under the front of the body. The fluid test may not be taking into account. We foung that a car with the least lift is actually what your looking for, in a sence, that would be the most downforce!

Kevin
Interesting data, Kevin. So you found that you had front end lift under all conditions? It wouldn't surprise me if my lift numbers weren't valid, given that the model has a smooth bottom rather than a hollow shell with a ton of geometry that causes all sorts of turbulence.

Given that the majority of racers have reported increased "front bite" and conditions described as "more steering" leads me to believe that maybe there is real downforce being generated at the front end. Your test setup certainly seems valid, with the one condition in question being that I didn't see you mention whether the floor was moving (conveyor belt, etc) or not. A stagnant floor in the wind tunnel will dramatically impact your measurements.

It's also possible that all of the downforce in a body is generated at the wing, and that the center of pressure is simply moved forward when it is averaged with front end lift. In that case, the perceived difference between some shells having more "front bite" than others might just be a matter of some having less lift at the front end than the rest.

Did you have the shells mounted to a chassis during the test? Or were they set up on some sort of fixture?
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Old 06-21-2006, 02:44 PM   #77
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Originally Posted by rayhuang
I hope you can get in contact with some race organizers for an exhibition class at a big race. Maybe just get 5 to 10 guys to run the body in an exhibition race. Wont hurt the racers efforts to do so, but could really open up the eyes of the general RC public that never find there way to RCtech.
That would be really interesting to see an exhibition class at a major race. It would give us an apples-to-apples comparison of all conditions being equal with the exception of the downforce generated by the shell.
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Old 06-21-2006, 03:07 PM   #78
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Sammy, I've watched my Nitro TC3 running a Mustang Body literally lift up in the front and grab 6' of air before barrel rolling for another 50'. Granted I was running a JP Novarossi geared for top end and the car was well exceeding 70 mph, that's more than most TC's will ever see.... We don't have any Nitro racing around here so I run whatever body looks good to me that week, time to switch to the new C6 Z06, I'm planning to get a full size so I gotta try it out... hahaha....
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Old 06-21-2006, 03:24 PM   #79
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Quote:
Originally Posted by Soviet
Ditto...LMP or GTP type bodies on touring cars would be one of the best things to come along in years.

Keep up the good work...

-Sean

Except after a year or two this Speed 8....



Would look like this Speed 8....



And novices would loose interest because the cars look goofy...like door stops.

A lot of you weren't around for the rise and fall of 1/10th pan cars. I was. I have heard this all before and saw a class I loved to race get killed by well meaning guys with what seemed like good ideas.
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Old 06-21-2006, 03:37 PM   #80
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Quote:
Originally Posted by AdrianM
Except after a year or two this Speed 8....

Would look like this Speed 8....

And novices would loose interest because the cars look goofy...like door stops.


A lot of you weren't around for the rise and fall of 1/10th pan cars. I was. I have heard this all before and saw a class I loved to race get killed by well meaning guys with what seemed like good ideas.
You are so right, man. If only we could understand exactly why so many forms of RC become these oblique shapes that hardly represent the original that the scale model is attempting to replicate. My theory is that, for some reason, many RC enthusiasts are not real car enthusiasts. They are in the hobby for the competition, and couldn't possible care less what their shells represented, so long as it gave them a competitive edge.

Pan cars were super hot when I first started racing ('91). I started out with a Bolink pan car and made my way to an RC10LSS before speeds got out of control. If we don't demand realism (with our pocketbooks), then realism will always give way to performance because that's what racers demand.
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Old 06-21-2006, 03:52 PM   #81
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Unfortunately, hardcore racers don't care for realism. Some people want to remove the "must resemble a real race car" rule for TC. I fully expect a bunch of "touring blobs" to emerge if that happens.

What you have done here, though, is awesome. Kudos to you for your efforts. IF we could have bodies that realistic and sweet looking that actually worked, that would be the best of both worlds.
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Old 06-21-2006, 04:09 PM   #82
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I still thint that Stock should be TC, 19t is GT and Mod is LMP.... Watching RC racing as a spectator is B O R I N G ! ! !
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Old 06-21-2006, 04:10 PM   #83
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I don't think its the hardcore racers who are pushing for that, its more likely the manufacterurs are looking to do so.

We need to understand that many "real car" companies are now asking for a royalty from hobby producers who make products that resemble their cars. GM, Ford and Ferrari have been very agressive on this issue.

I think if we all say to the manufacterers that we're willing to pay $50plus for a well molded scale body with quality vinyl stickers, masking and overspray film, you might see more scale looking bodies available. Just be ready to pay for it when it comes.

However, if $20 is all we're willing to pay, then expect obscure looking cars with parts from all sorts of cars because thats what hobby mfgs have to do to put out product without incurring any royalty payments.

Quote:
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Unfortunately, hardcore racers don't care for realism. Some people want to remove the "must resemble a real race car" rule for TC...
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Old 06-21-2006, 05:30 PM   #84
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Quote:
Originally Posted by SammyXp
Did you have the shells mounted to a chassis during the test? Or were they set up on some sort of fixture?
We did have them mounted on chassis. We locked the bearings on the chassis to keep it from rolling backwards also. That may have had some kind of effect from the drag. We did also measure the drag by attatching a string and fish scale. I don't think that scale was not accurate enough to determine a reliable determination on the drag coef.

We did have a stationary table. I also don't believe that had as much an impact on the results though.

Good luck
Kevin
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Old 06-21-2006, 05:43 PM   #85
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The most sucessful full scale racing series (NASCAR, F1, WRC, etc.) have strict technology and perfornace controls in effect to limit development and to maintain close racing.

We need the same to happen more frequently in R/C.

As far as r/c racing being boring to watch...yup...it is. A-Mains are cool to watch but thats it.

There are a lot ofther sports that are fun to participate in but a real drag to watch...has anyone caught a paintball tourney recently

I dont think we will ever have TV coverage but we can get more R/C fans to big races to take in the event and we can get more outsiders to stop by and see how much fun we are having.
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Old 06-21-2006, 06:10 PM   #86
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I'm not saying that hardcore racers want that. It's just they will use what works, and it's not any concern to them.
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Old 06-21-2006, 06:25 PM   #87
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Well I always thought that one would use the rear wing to trim out the balance of the body in relation to front downforce as to front lift for the front end shape can not be changed or mounting the front High or low would give you more or less steering and use th rear wing to balance it all out I might have been wrong all of these years
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Old 08-15-2006, 09:36 AM   #88
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Havn't seen anything posted on here in some time. What is the latest or has this "project" been cancelled? I was looking foward to trying one of these and actually has some others here interested in running them as a class.


Mark
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Old 08-15-2006, 10:15 AM   #89
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Quote:
Originally Posted by Rainey
Havn't seen anything posted on here in some time. What is the latest or has this "project" been cancelled? I was looking foward to trying one of these and actually has some others here interested in running them as a class.


Mark
It's a shame, but this project is teetering on cancellation. The guy that has been walking me through the vacform process is moving. If anyone is interested in buying the partially completed prototype mold, email me at [email protected]
I'm hoping to complete it before he leaves, though.
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Old 08-15-2006, 10:17 AM   #90
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I was going to get one.
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