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Old 05-15-2006, 03:15 AM   #61
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Originally Posted by WheelNut
Dale- What you really ought to do is to get that mini windtunnel and start expirementing with real areo kits for RC cars. Undberbody diffusers, full underbody kits to speed up under car air flow, wheel well kits to reduce turbulence and keep the pressure under the car. Mabye even mess with some fans under the body . I don't know why this hasn't been explored yet, huge gains could be made in speed on the track if we had ultra slippery cars that generated the same (or more) amounts of downforce than we have now. Not to mention since no one else is doing it and you came out with it you'd be the dominate force in racing bodies for some time. Unless ROAR doesn't allow ground effects kits to be fitted onto RC's.

If I recall, there was a car that ran in CAN-AM back in the day which used fans to create a vacum under the car to better hold it to the track. I believe it was banned after one season...

Underbody pans and diffusers would be nice, however one smack on the boards and there goes all your undercar junk all over the track, or it'll get bent up into your wheels, hence still jacking you up.
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Old 05-15-2006, 05:22 AM   #62
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Soviet Ground effect have been done found to give a big advantage and subsequently banned by the brca and IFMAR, Some guy did in Pro ten in 1990's when it was big.
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Old 05-15-2006, 08:18 AM   #63
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Default ground effects & wind tunnels

You guys have all brought up some valid ideas, and some that were...hmmm...not. In my opinion "Full" ground effects will never be seen in electric rc cars for a few reasons.
A - Weight is a bid factor. All those new components stuffed in to the body (enclosed wheel wells, venturi tunnels etc) will all weigh enough to negatively effect the CG (center of gravity) and run time. Can you say "minimun weight?" Ya right - good luck! Speaking of run time - if anyone ever built a "sucker car" like the Chaparall 2J as was mentioned - they would have almost no run time (even with todays awsome cells) because of the drag and load that are induced onto the entire drivetrain.
http://www.petelyons.com/Photo%20Gal...l2JSucker.html
B - Will this new underbody complexity survive a crash? Crashes are inevitable unless you're Marc Rheinard. C - How many tracks have a smooth enough surface to allow full ground effects to even work at all. When qualifying resumes at the Brickyard next weekend (for the Indy 500) the teams will be making ride-height adjustments in "thousandth of an inch" increments because these cars rely so much on ground effects in the corners. (even though IRL cars are a flatbottom design with small diffusers - they are not full gr. effect cars) Ground effects are all about the relationship of the car to the track surface - and it needs to be consistent for there to be any tuneability or performance gain. Because rc cars are by comparison very light and are raced on surfaces that are not sealed (like old porous asphalt) and also have a lot if irregularities and bumps, our 1/10th scale cars spend a lot of time bouncing. Some tracks are smooth as glass like Tamiya's, but the average ones are not. And parking lots? Fugitaboutit - usually horrible. This condition greatly reduces any "effect" at all from ground effects. D - Cost. If somehow someone came up with fully sorted-out ground effect components to sell, I'm pretty sure that there would be a lot of complaining about "One more expensive thing I need to have - with a box of spares." It would lead to a "have vs. have-not" situation which is always unhearthy in any motorsport class.
The only place I can imagine that ground effects could be developed into a benefit is in gas-sedan and gas onroad racing. RC Oval racing already kinda taps into some ground-effect principles because of the way the bodies are trimmed, their stiff chassis and sustained high speeds.
Fun stuff to talk about - hard stuff to develope for retail. In my situation, my time is so stretched, I pretty much need to spend my time on "sure- thing" kinda projects were the odds are good for a return on my time and investment.

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Old 05-15-2006, 09:54 AM   #64
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At the Encino Velodrome, some of the modified guys have been using special made carbon chassis that have the battery down the middle bottoms completely seald. some run with rear bumbers on with either a wing or body spoiler. and some have a rear diffuser built into the body. They also use special super speed way bodys with low down force. A hi downforce body creats to much down force and you can actually hear the tires being forced down onto the asphalt.

Also the track is has bumps and seams. the bumps are exacerbatted by the high speeds, so in order to keep the front ends down,they have gone to an full independent front suspention with oil filled shocks.

I have still seen some blow overs. The air can still get underneath the chassia and lift them off the ground.
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Old 05-15-2006, 12:30 PM   #65
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Dale,

I still think we should grab some bodies and go over to Spitzers in Indy. He has a mini wind tunnel perfect for us to use. To bad PRI went to FLA.!

SC

BTW...if we go 40mph in "real mph"...and these are 1/10th scale...if my math is correct, that would be 400mph in scale...you're right Soviet, aero makes no difference at alll...what were we thinking.
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Old 05-15-2006, 02:02 PM   #66
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For the peoples that are posting about scale speeds, I wouldn't even consider that, only because 1. there is no way of scaling of time, 2. there is no scaling of the air molecules that the body is pushing around. We should be keeping with the idea that it is what it is. In other words, the cars are doing actual kph, or mph - whatever you're used to, and the down force is measured in real (not re-scaled) weights. The reynolds numbers coming out of the dyno will not be scaled to match the scale of the body size. They are full size air molecules with real scale speed measurements.

Interesting info on those velodrome set-ups, though.
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Old 05-15-2006, 05:51 PM   #67
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Thumbs down scaled up speed

timmay70;
Your points were worded excellently. I'm in full agreement (if that's worth anything for you to know)
I'll never forget the magazine ad done by S & K back in the mid 90's - "Now, you can race a real Thunderbird Stock Car at over 400 mph for only $300 !!" It was for a pathetically executed RTR el-cheapo fiberglass plate, no-suspension pan car. They even put it in Car & Driver and Racer magazines. Kind of embarrassing for the whole rc industry. Hey Soviet - there's your snake oil.

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Old 05-15-2006, 10:22 PM   #68
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Quote:
Originally Posted by Soviet
Eh...I'm mostly jabbing Dale. Anyhow...My point has never been that we can turn just as fast laps with a shoebox instead of a slippery and aerodynamic body.

My point is that bodies with nearly the identical side and frontal area, plus similar wings DO provide nearly identical results.

What I'd like to see would be a rundown of various bodies Reynolds numbers and frontal area. That would be some interesing data. I'd like to compare the Proto Mazda 6, Proto Nemesis, Parma Alpha and Proto Stratus Mk II and III.
I can tell you for a fact that the Mazda 6 and the Nemesis do not handle the same.. The "6" has more down force than the Nemesis,A lot of racers don't understand or want to believe that "just" a body can make a huge difference.I have been racing where all i did was change bodies and went from middle of the B to TQ and all i did was change bodys.My car went from being very lose to hooked up and all it took was changing bodies..4 body clips.. Don't get the impression that I'm picking on you, but to me it's just another tuning adjustment..Their are certain tracks where one body just works better than others.. I always bring 3 bodies to the races,High,med. and low traction.You should try it sometime..it does work
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Old 05-15-2006, 11:04 PM   #69
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i have an example of just how much areo plays in rc's. take ur 12th scale car and remoneve the body, drive it around the track, then put the body back on and continue running, and also removing the rear panel below the rear spoiler will reduce drag, i have done both ways, and it makes a huge difference.

also i have found different bodies for 12th scale and 10th scale handle differently. for 10th scale, the cadillac cts body for touring handles really nice, aswell as the mercedez clk body. the body i have found to handle the best for 12 scale racing is the speed 12 (heavy version)


areo plays a big part.
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Old 05-15-2006, 11:17 PM   #70
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Originally Posted by cramer
Dale,

I still think we should grab some bodies and go over to Spitzers in Indy. He has a mini wind tunnel perfect for us to use. To bad PRI went to FLA.!

SC

BTW...if we go 40mph in "real mph"...and these are 1/10th scale...if my math is correct, that would be 400mph in scale...you're right Soviet, aero makes no difference at alll...what were we thinking.

I never said that aero-design made NO difference at all. My point is that all the variables in racing RADIO CONTROL cars on mostly imperfect surfaces negate the supposed "gains" seen in laboratory environments.

In other words a TC shell is a TC shell and generally is "good enough for government work."

Thats my point and thats my opinion.
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Old 05-15-2006, 11:21 PM   #71
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It must be the internet, or perhaps some folks reading comprehension skills; however after finishing reading the rest of the responses it seems that nobody gets my point.

Subtle and nuanced conversation via text is exceedingly difficult.

So go ahead...join the group think...swim with the school, trample with the herd.
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Old 05-16-2006, 12:29 AM   #72
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D'oh! I had it all wrong, but now I get it. I thought government work was all about swimming with the herd and trampling with the school. But I'm still confused because sometimes a TC shell is not a TC shell? At least we can agree that it all tastes good!

Dale
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Old 05-16-2006, 12:38 AM   #73
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Ah... such a heated thread
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Old 05-16-2006, 12:58 AM   #74
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Quote:
Originally Posted by daleepp
D'oh! I had it all wrong, but now I get it. I thought government work was all about swimming with the herd and trampling with the school. But I'm still confused because sometimes a TC shell is not a TC shell? At least we can agree that it all tastes good!

Dale
Look man...just start pumping out GTP or CAN-AM shells and I'll be happy.
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Old 05-16-2006, 07:31 AM   #75
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Default KarpetRacer93

This thread's been all over the map. Somehow I've forgotten to commend the guy who started the tread, KarpetRacer93, for his science project work regarding TC wings. I hope you continue to explore things like this when you get back to your track in Sept.

Keep up the good work and thanks for sharing your results with all of us.

Dale
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