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Anyone have Aero questions?


@NineLivesJohnny
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59 minutes ago, XelderX said:

This is way more interesting than anything going on in Champcar right now.

ok join the challenge. rules are you have to use the standard pinewood derby kit to start, wheels block. Estes A8 motor, that's it. anything else is open

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1 minute ago, TiredBirds said:

ok join the challenge. rules are you have to use the standard pinewood derby kit to start, wheels block. Estes A8 motor, that's it. anything else is open

 

What's the competition format? I have a little bit of brain capacity left from all the other projects going on. 

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9 minutes ago, TiredBirds said:

ok join the challenge. rules are you have to use the standard pinewood derby kit to start, wheels block. Estes A8 motor, that's it. anything else is open

Length of race? Surface? Surface prep / VHT? How wide are the lanes? Guardrails?

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2 hours ago, XelderX said:

 

What's the competition format? I have a little bit of brain capacity left from all the other projects going on. 

we are trying to find the smoothest surface available. Most likely a parking lot.  You take a pinewood derby kit. You have to use the standard block and wheels. The engine is an A8-3 Estes. all else is fair game. Longest run wins. NO wire guides all Free rocket over ground. 

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  • 3 weeks later...
On 5/21/2020 at 5:47 PM, TiredBirds said:

we are trying to find the smoothest surface available. Most likely a parking lot.  You take a pinewood derby kit. You have to use the standard block and wheels. The engine is an A8-3 Estes. all else is fair game. Longest run wins. NO wire guides all Free rocket over ground. 

I think you are gonna be firing rockets around a parking lot.

 

I seriously doubt any of them are gonna go any kind of straight if my days of racing co2 cars and doing rocketry are any indication.

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10 hours ago, wvumtnbkr said:

I think you are gonna be firing rockets around a parking lot.

 

I seriously doubt any of them are gonna go any kind of straight if my days of racing co2 cars and doing rocketry are any indication.

we shall see. round 2 coming up. I have a new design and it looks fast just sitting on the table. 

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  • 3 months later...
  • 4 weeks later...

Imagine if you will, that someone is crazy enough to actually decide to race a FWD hatchback.

 

My goal was the eliminate the understeer with the splitter and balance the car with the rear sway bar, and not have drag of the rear wing at all. Worked very well at Nelson Ledges and Pittrace in our Coved shortened season.

 

Questions:

1. If we add the rear wing, how much more front downforce can we expect to get in the front to get the car back to neutral? I do not think we need the wing.

2. With our protruding bumper, and low water temps, we can block off some of the air into the radiator. Is it better to tape the grill above the bumper, or add deflector plates under the bumper (as shown). The holes in the bumper are right in front of the intercooler and I would like to keep them open. So which is best for drag and downforce? Blocking off the grill, the bumper, or below the bumper.

3. I have the "required" NACA duct in the passenger wing window to cut down the open area. Should we make new ones with the 1" lip? What angle on the lip is best? 30 degrees?

4. On the 1/2" splitter leading edge, is a rounded radius that is equal top and bottom best? Or all to the bottom with a square top edge? Or the reverse?

5 The hood is getting replaced to eliminate the plastic exit ducts, remove the turbo cooling scoop, and leave the NACA duct to the oil cooler unfortunately. 

 

Suggestions?

 

6done (2).jpg

5done (2).jpg

splitter fix.jpg

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  • 4 weeks later...

i love your ramps. 
What's the cross weight? ideally we want to have the aero load = to the chassis cross weight. 
The splitter looks effective like it could be making a real amount of downforce. without anything in the back the rear is going to  make lift. meaning as you go faster the front will be pressed down and the rear being pulled up. on slow tracks it might not an issue. but on the faster ones the car could become dangerous to drive. one of those things that's not a real problem, until it is. 
that being said with a heavy front weight bias you won't need much downforce in the rear to bring a balance. We where seeing 55" wangs working well at a low aoa on FWD car.  we even won the highly competitive Honda challenge class with that exact set up on an integra. and about adding drag our 70" wing @ 0*aoa only requires 2.2hp to move 100mph. a 55" wang would be <2hp   
  

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Looks like mine plans for the Rabbit are right on line. Moved the air dam forward to front of bumper and adding an actual splitter, the air flow to the radiator will be from the center openings and thinking of taping off the grille with a strip or two to remove if needed for cooling, Jay had me declare the air dam as a splitter also as we have the points to work with so I am making it as well.

IMG_20201117_073007292.jpg

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How much hp am I using with this wing? It's at 6 degrees AOA, which is what the drivers liked. I was going to reduce the AOA but they said no.  :)

 

1262071232_paulscar3.jpg.bd58783fe266c562397a1d66a21abc25.jpg

 

Next year it'll get a bigger splitter, reduced grille and brake duct openings, covered headlight openings, wheel spats, and a hood vent. Any other suggestions?

 

Edited by mender
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I do have a questions for an 86 mustang hatch back. Which is better a spoiler or wing? I see $100 wings with brackets. I am sure not all wings are equal. How big of side plates can you go? Double wing over single wing?  I have factory spoiler only. Is there a dramatic change in the car when adding a wing. Will aero help my car turn or is this all straight high speed benefits. Splitter only? The car is only about 3 to 4" from the ground in the front. Your help will be appreciated. 

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So I've got an aero question regarding front splitters.  How low is too low? We run your splitter and mounts on the Miata, and we haven't really seen any indication of dragging/scraping or other contact with the ground, even after Sebring.  I know you want some air going underneath the nose of the car so that it can be accelerated and cause a pressure drop.  I also  know the Nascar guys try to run the nose as low as possible.  Our car is about as low as it can get without negatively affecting suspension geometry.     

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Hard to compare NASCAR to what we do. Their oval tracks, for the most part, are much smother than most road courses. Might be because the ovals do not have big curbs. If I am still up to date on NASCAR tech, they also run a lot of coil bind suspensions, with the tire becoming the biggest spring once up to speed. 

 

That allows them to run a pretty low splitter with out worrying about fluctuations in height and the resultant changes in downforce as spring rates on those tires are in the 600-900 lb range.

 

Find some pictures that compare a NASCAR teams short track, restrictor plate and road course cars. They are significatntly different from one another. I am pretty sure the road course cars have a higher ride height and do not run any where near the same springs as the oval cars.

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On 11/24/2020 at 11:40 PM, mender said:

How much hp am I using with this wing? It's at 6 degrees AOA, which is what the drivers liked. I was going to reduce the AOA but they said no.  :)

 

1262071232_paulscar3.jpg.bd58783fe266c562397a1d66a21abc25.jpg

 

Next year it'll get a bigger splitter, reduced grille and brake duct openings, covered headlight openings, wheel spats, and a hood vent. Any other suggestions?

 

is that our wing?

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