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Old 05-10-2006, 05:10 PM   #16
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Soviet, try taking the wing off of a sedan for a few laps. Let us know what you think.
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Old 05-11-2006, 08:13 AM   #17
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Soviet;

I must say, you crack me up. lol Your posts are always so ....entertaining. Just wondering, do you follow Formula 1 at all? You know, the open wheel teams that have 600 employees, 400million dollar a year budgets, and wind tunnels that rival and even surpass the level of aero-technology in any space program, in any country in the world. (and yes, your once-great nation included - lol)
Well, if you've ever noticed, the top 5 or 6 teams very rarely show up two weeks in a row, or even a second year in a row (at the same track) with the same aero package - even when the rules remain constant. The changes they make to their wings, spill plates, barge boards, and diffusers etc are so minute, that only a trained eye can readily notice the changes. Weekly, there's an addition or removal of a little gurney flap, a tiny fin, a little inward curve here and outward curl there - all dictated by the wind tunnel "numbers" as they are decoded by some very inteligent aerodynamicists. Do they come up with these little novelty pieces by chance? No, they have a team of modelmakers making 3D parts that are tested in the windtunnels that tend to run 24 hours a day, 7 days a week - with one day off a year - usually Christmas day.
Soviet, you must think these guys are absolutely nuts - making all these silly expensive little changes when it would be a lot easier and cheaper to give the drivers a small "sugar pill" and convince him that "Honestly: tests have proven that this pill will help you shave a tenth off you best lap time - and give you more stamina and concentration". Wouldn't you agree? Or hey - maybe thay are doing all this needless work and making all these little detail changes to the racecar just to make the driver "think" that they are actually improvements - which will in turn have a psychological effect on the driver and make him drive quicker.
Seems to me that one would have to conclude that all us "aero nuts" are in fact actually nuts or there is still a lot to learn and a lot to gain (performance wise) in the area of aerodynamics. Especially in electric rc cars where our finite power source dictates a body with a relatively efficient shape, and our crazy power-to-weight ratio dictates a prescribed degree of downforce.
But then - you decide. You are the expert.
http://www.formula1.com/insight/tech...6/755/271.html

Dale
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Old 05-11-2006, 08:37 AM   #18
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While Im no aerodynamics expert; I am not the kind of person to be driven by whats hot asfar as bodies go. When I first got into electric racing it was at the 18th scale level with my M18. I ran a lambo body that looked KILLER with the HPI stock wing. I had a horrible time of making the car handle and I attributed that to everything BUT the body. I too felt that a car so small wouldnt be affected by aerodynamic forces. A friend of mine FINALLY concived me to try a TC body with its wing...I did; and thats the day I stopped beleiving aerodynamics plays no part in RC racing.
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Old 05-11-2006, 09:07 AM   #19
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rc wings are larger by scale because air molecules are huge in comparison to real scale. I assume that small changes would not affect the aerodynamics of the rc car as it would a larger car.

the aero package intrigues me because I am currently building a super speedway car Velodrome racing, powered by an novak 4.5 brushless motor. We hit speed of up to 60 + and aerodynamic drag will have a dynamic affect on these cars.

There has been discussion that by leaving on the rear bumper, as opposed to cutting it out, along with the proper placement a rear wing would be more efficient and have less drag. I am building a body with the rear bumper left on and the wing suspended near the edge of the rear deck. The wing will have no down angle and will have high side dams. I am experiementing with a rear under wing, that will control the air exiting the rear of the car. the idea of small air dams along the roof and rear window as mention before and as seen on nascar intrigues me, although they may not be allowed. Further,in order to make the roof air dams to work they will have to be larger than scale because of the larger size of the air molecules. I can make them removable so if the tech people object I can remove them.

The is a wip tha I have been working on this since December. it should be ready to go around august. then I will have my own aero experiment.
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Old 05-11-2006, 09:12 AM   #20
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I believe aero is important in all scales. Back in my slot car days I had a 1/24 scale Cox Chaparral (circa 1967) and a Cox Ford GT-40. I switched bodies on chassis and no matter what I did, the Chaparral was never as fast... never as good handling... as the GT-40. Being a die-hard Chevy fan, this was a hard pill to swallow.
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Old 05-11-2006, 11:21 AM   #21
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try puttin a group C style body on your touring car. The difference is amazing, im very interested in aerodynamics and i have to say i can feel differences between bodyshells. You do need to run them back to back to feel it sometimes though

A guy at my local club didnt believe me, he usually ran a HPI Lotus Elise body so i lent him one of my Protoform Stratus 2.0s he came back afterwards saying he couldnt believe how much difference it made and the laptimes..... 3tenths per lap faster consistently than his best run up to then, he then put the Lotus back on to make sure it wasnt just track conditions, again on average he was approx 3tenths slower per lap.

This is on a polished wood surface with a 19turn motor, not the fastest class by any means but the difference was visible. When i do nationals its a serious part of car setup. Bodys and wings make a difference!
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Old 05-11-2006, 01:19 PM   #22
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Default ahhhh...Cox Chaparral

BimmerDriver;

I know it's off topic - but your mention of that Cox Chaparral sent me back in time - like I had gotten into Rocky & Bullwinkle's "Way-Back Machine". I got one for Christmas back in 66 or 67 and I absolutely loved it. It was my first ever motorized "anything". I remember working on it while listening to the Beach Boys on my cheap Japanese portable radio. Real magnesium chassis and 5-spoke wheels with those heavy-as-lead solid silicone white-letter tires. I'd simply kill to get my hands on an original. Jim Hall was/is one of my alltime racing heros.

Dale - PROTOform
(ps: I like your user name - I drive one too)
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Old 05-11-2006, 01:33 PM   #23
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I just checked ROAR rules for wing mounting. It has to be lower than the top of the roof. There are no rules against having a wing hanging over the sides. So I guess it is perfectly legal to run a 200mm wing on a 190mm body.
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Old 05-11-2006, 01:55 PM   #24
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Quote:
Originally Posted by KarpetRacer93
I just checked ROAR rules for wing mounting. It has to be lower than the top of the roof. There are no rules against having a wing hanging over the sides. So I guess it is perfectly legal to run a 200mm wing on a 190mm body.
No its not....look at page 48 of the ROAR rule book....the wing can only be 190mm long. So you cant run a 200mm win on a 190mm body at a ROAR event.
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Old 05-11-2006, 08:13 PM   #25
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Quote:
Originally Posted by daleepp

I know it's off topic - but your mention of that Cox Chaparral sent me back in time - like I had gotten into Rocky & Bullwinkle's "Way-Back Machine". I got one for Christmas back in 66 or 67 and I absolutely loved it. It was my first ever motorized "anything". I remember working on it while listening to the Beach Boys on my cheap Japanese portable radio. Real magnesium chassis and 5-spoke wheels with those heavy-as-lead solid silicone white-letter tires. I'd simply kill to get my hands on an original. Jim Hall was/is one of my alltime racing heros.

Dale - PROTOform
(ps: I like your user name - I drive one too)
Friday nights when the other guys were at the dance down the block, I was hangin' with the "big guys"... who drove real cars. I was only a year or two away myself. I got the GT-40 second hand, from my dad's boss' son. His parents didn't want him being with "that crowd". Would have paid off if he stayed with us, he turned into a drugged-out loser.

They had a figure-8 and a road race track, 126' if I remember. I had the "deluxe" Cox controller, with the thumb plunger and a phone jack. I also had a pan chassis twin motor 4wd Lola that stuck like glue.

The track closed soon after I got my license, I got into big cars. I spent the next 18-20 years working on an outlaw sprint car. (ever heard of the original outlaw, Scruffy?)

I was made manager of his go-kart track and in order to have a year 'round job, we put in an American Hill Climb Raceway and a radio control hobby shop. (That's when I got my start in RC.) We raced Womps, Flexi-cars and Grp 15's. Hasse Nillson helped me modernize the track, wider lanes and glassy smooth epoxy surface; the Grp. 15's covered the 136 feet laps in under 3.5 seconds. (Thank God for computerized lap counters!)

In 1992 I got my first "real" job they cut up the track and sold it somewhere in NJ. I left my RC cars in the attic at the track and didn't touch a controller again until 2004.

Sorry to use so much space off topic. Thanks for letting me reminisce

I like my Bimmer too, a REAL Ultimate Driving Machine... 1991 E30 325i
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Old 05-11-2006, 08:32 PM   #26
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Dale, have you put any of your bodies into a wind tunnel? or attempted to measure downforce? That would be fascinating data - what front and rear downforce is generated at what speeds.


In offroad (EP) A few years ago we were playing with mounting wings directly onto rear hubs so that any downforce wasn't interfering with suspension. The team we were running for at the time said they had tested and found that offroad wings generated no downforce, just what they called "stabilising drag". We put out experimental wings away in the cupboard and went back to suspension tuning!
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Old 05-11-2006, 09:11 PM   #27
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I was a firm beleiver that aero wasn't of that much significance in 1:10 rc.
Scaling wings down does not allow for a similar generation of downforce. Hence, beautiful gentle airfoil shapes have no place on an rc car.

That said, the same aerodynamic principles still do apply. Chucking a flat board wing on the back will generate an appreciable amount of downforce. Just as a paper aeroplane with flat wings can still fly.


Anyone who's run a current racing body (Eg. protoform mazda 6, stratus 3 etc..) will tell you hoiwever, that there most definately is a difference in body shape aerodynamically speaking. Running a more "Realistic" scale body does make your car much more unstable.

Whether a 200mm wing that much more effective than a 190mm i'm not sure of. But, do consider that the wider wing represents a sizable 5% increase in working area, and that the wing would most likely be exposed to a greater % of unobstructed clean flow. It's not hard to concieve that this small increase could result in a measureable gain. It's certainly not a linear increase in downforce for the extra width!

(By clean flow - i mean most bodies taper vertically toward the roofline. So a wider wing can be seen with nothing in front of it, when viewed head on. Therefore it is aerodynamically MORE effective than the middle sections which deal with "dirty" air )

Not to mention that the wider wing will also be more efficient when you need it most (in corners). The apparent frontal aspect of the wing would be increased exactly where you need it most.

The sceptic in me screams - placebo effect. But it's not entirely inconceivable that the wider wing could indeed lower the laptimes.
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Old 05-11-2006, 10:08 PM   #28
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Quote:
Originally Posted by Soviet
As of now, you're crossing over into the Voodoo and snakeoil side of R/C touring, a place where people SWEAR up and down that they can "feel the difference" between a Mazda 6 and a Nemesis.
Well, I have not tested the Nemesis. I can certainly tell the difference on the track between a Mazda 6, Stratus 2.0, Protoform Alfa and Parma Alfa. There is certainly a difference. Even in 12th scale between the CEFX, Speed 8 Parma, Speed 12 and Speed 12B.

IFMAR actually has a rear wing width limit of 170mm or something. It was nuts at the Worlds in 2000. Everyone had to bolt on Yokomo wings to be legal. The car was different for sure.

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Old 05-11-2006, 10:29 PM   #29
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I think Iv'e figured it out:

Soveit is a Placibo, looks the same, but just doesn't do anything.

Try running the Mazda 6 in club trim, with full height wing, and then trim it to ROAR regs,115mm max height with min roof height of 115mm, big diff. To get to ROAR regs there is not much wing left.
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Old 05-11-2006, 10:48 PM   #30
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I've never tried it, but I think a parma alfa with a bigger/less flexible wing could be good on asphalt at the club level.... It's the coolest looking shell out there IMO. So is the MG-Z, very nice looking.

Whether the difference is real or not, I have seen cars with Lambo shells and the such and they sucked (but it could have been the driver)

There used to be a guy at my track that got into the 'A' all the time with a $#itted-out corvette shell.

MAybe one of those old Bolink 'legends' shells is the hot ticket
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