NONACK wrote: You keep mentioning wings- why not suction? Used leafblowers are cheap... The undertray/skirt design could be configured to make it an effective 50/50 under vacuum.
Not sure used leaf blowers really have the suction necessary for something of this size. Sure they worked on a go kart but larger vehicles require larger (and more expensive) solutions.
Besides we have a much worse idea in mind...this is all about bad ideas right?
JThw8 wrote: Besides we have a much worse idea in mind...this is all about bad ideas right?
JATO rocket powered downforce? 
I am sure you could come up with a homebrew long burn solid rock that would provide a significant amount of downforce...
wait, someones at the door, oh, its homeland security... 
When looking at wing placement, keep in mind that it's best to have your front/rear downforce distribution similar to your static weight distribution. Otherwise, you'll have a handling change as the downforce fluctuates with speed and slip angle. Having a car with all the weight on the rear axle and a big wing in front of the driver would mean a big shift in handling.
In reply to JThw8:
I think 4-5 of the backpack units could probably make just as much as wings at low speed, provided those wings aren't of the A-Mod/FSAE low speed variety. I could be wrong though...
Keith Tanner wrote: When looking at wing placement, keep in mind that it's best to have your front/rear downforce distribution similar to your static weight distribution. Otherwise, you'll have a handling change as the downforce fluctuates with speed and slip angle. Having a car with all the weight on the rear axle and a big wing in front of the driver would mean a big shift in handling.
Keith, is right for a typical build, but this build will wind up running in a very narrow window of speed, so the balance could be used to get awfully close to a total of 50%/50%, with the aero and weight working together. The slip angle wont be problematic if the wing is built symmetrically about the centerline.
How much do you want in terms of aero? Since this is a one-of car the wing can be BIG. Like wider than the vehicle and as long as you can stand to build. Wings do work more efficiently when the they are wider than they are long (aspect ratio).
stafford1500 wrote: The slip angle wont be problematic if the wing is built symmetrically about the centerline.
Actually it still could be. Even with unbiased aero, if you have a big weight vs. downforce imbalance you could get the same handling changes that happen at different speeds happening at different slip angles, regardless of speed.
Feel free to paypal donations and I'll work with all of these ideas ;) Otherwise its really big tires and a little surprise AngryCorvair came up with. Remember I have no intention of being competitive, I just wanted an excuse to build up an autocross sandrail and get out of the house for a weekend ;)
JThw8 wrote: I probably won't run an alternator though, I'll just have a big deep cycle battery and one for a backup. I ran my Solo Vee on battery only and at one event with 2 co drivers it made over 30 runs in a day without tapping the battery out so it should be ok.
Wouldn't a VW alternator and lawn tractor battery weigh a fair bit less than a "big" deep cycle?
Kenny_McCormic wrote:JThw8 wrote: I probably won't run an alternator though, I'll just have a big deep cycle battery and one for a backup. I ran my Solo Vee on battery only and at one event with 2 co drivers it made over 30 runs in a day without tapping the battery out so it should be ok.Wouldn't a VW alternator and lawn tractor battery weigh a fair bit less than a "big" deep cycle?
Less about the weight and more about the parasitic drag on the motor (and the fact that the alternator I have seems to be junk and I don't want to buy another one) Plus since I'm putting the battery up front to move weight around I actually don't mind a bit of extra weight up front.
It seems I'm at this really odd scheduling/coordination part of the project. Believe it or not aside from waiting for parts and money for parts this thing is going to reassemble very quickly. However...
It is my goal to keep it rolling as long as possible so I can move it out of the shop for other projects as needed. So those times when I do need to make it immobile (all the suspension work I have to do now) need to happen quickly.
I'm at the point where I can disassemble the rest of the rear suspension and put it back together and I'll have the rest of the parts for the front in a day or two. But before suspension assembly I want the frame painted. It feels like there are so many larger projects I should be working on but from a pure timing standpoint I need to spend any free time this weekend (little since the wife is tired of being a car widow already) welding all the tiny holes in the tubes from where the skin was screwed on then sanding, sanding and more sanding. Sanding tubes is a huge pain.
Then I can pull apart the suspensions, paint the chassis, and begin reassembly of the suspensions, it should only be immobile for a week or less that way.
There's no real point to this post, just thinking out loud.
I like the term car widow. My wife feels that way often. She just hasn't had that term.
And the scheduling thing is always tough. Im in the same boat quite often.
Forget downforce and expensive rubber, you need to exploit the rules a bit harder and go with counterweight.
Not sure exactly how to sneak it into the rules, but what you do is tether a second identical car to the center of mass and have it run on 180 degrees away from your (piloted ) vehicle. It works for the NASA G simulator, so why not here?
NOHOME wrote: Forget downforce and expensive rubber, you need to exploit the rules a bit harder and go with counterweight.
See earlier mentions of bad plan being brewed thanks to member AngryCorvair ;)
JThw8 wrote:NOHOME wrote: Forget downforce and expensive rubber, you need to exploit the rules a bit harder and go with counterweight.See earlier mentions of bad plan being brewed thanks to member AngryCorvair ;)
???? I don't see where he has posted in this thread?
NOHOME wrote:JThw8 wrote:???? I don't see where he has posted in this thread?NOHOME wrote: Forget downforce and expensive rubber, you need to exploit the rules a bit harder and go with counterweight.See earlier mentions of bad plan being brewed thanks to member AngryCorvair ;)
No, I had mentioned earlier that he contacted me with an idea that we're working on together. I don't think he's posted here.
JThw8 wrote:NOHOME wrote:No, I had mentioned earlier that he contacted me with an idea that we're working on together. I don't think he's posted here.JThw8 wrote:???? I don't see where he has posted in this thread?NOHOME wrote: Forget downforce and expensive rubber, you need to exploit the rules a bit harder and go with counterweight.See earlier mentions of bad plan being brewed thanks to member AngryCorvair ;)
Just checked...your form NJ. You can just Mob-up and have like, a "No Show" entry and still go home with all the chips.
Well I ended up doing more stuff around the house/marital harmony things than work today but I did get the clean up on the transaxle finished.
I also got about half of the holes welded up in the frame. Every little bit of progress helps I guess :) Tested some paint on the frame, I had a few cans of this almond color sitting around, might just use them. I'm planning on sticking with rattle cans, I really dont feel like loading up the guns to spray it with real automotive paint although I do have a gallon of viper yellow that isnt doing anything so you never know..
NOHOME wrote: Just checked...your from NJ. You can just Mob-up and have like, a "No Show" entry and still go home with all the chips.
Or...he can run first and then order a "traffic study" for the skidpad.
JThw8 wrote: Well I ended up doing more stuff around the house/marital harmony things than work today but I did get the clean up on the transaxle finished.
I'm going to suggest that using a real gun is going to be a lot faster, cheaper and easier than a bunch of rattle cans. Tube frames have a surprising amount of nooks and crannies and surface area, it's going to take forever and eat a lot of cans.
Plus, yellow.
I like the almond and gunmetal and polished idea.
As far as paint goes Im still waffling. To be honest it probably won't be yellow. The whole reason I have a gallon of it is it came with a project car I bought which was in primer and the owner intended to paint this yellow. I dont hate yellow but it requires the right car and that one wasn't it, so it sits. It wouldnt be terrible on a rail but not really what I have in mind for this one either. I may go silver and purple, not entirely sure.
Keith I get what you are saying about the pain of spraying a tube frame. I dont think an automotive gun makes that any easier. Because this frame is pretty abused it wont ever be very smooth so Im leaning toward just rolling it with thick foam rollers, might be the easiest way to do it.
Next up, today's progress report.
I started today by welding up the rest of the little holes in all the tubes so that's finally out of the way. Then I figured as long as I was welding and cutting and making a mess I should get back to making the front beam a little better.
I had been cleaning it up and cutting off all the extra welded on junk from the PO.
But all the clean up in the world wasn't going to fix this...
Aside from the rust the end supports were fairly mangled. Since the beam is fully welded to the chassis these aren't as critical as they would be in a bug where its just bolted in the center but I figured it was best to have something there. Time to make a little something.
Start by drilling some holes in a big chunk of box steel I had laying around.
Then split that in half
Trim the ends
then fold them over and weld them
A few test fits, some trimming then weld it in place
Just "thumbed" though this thread.
Didn't notice anyone asking about oiling under constant cornering. I'm not that familiar with how VW's oil and drain, so I'm just wondering how concerned one may have to be if you are constantly cornering at over 1g of load?
Or even what the effect on a carburator would be when you have the bowl of fuel basically at an angle. Duly noting that the carb would effectively be slanted at just over 45 deg (at 1g) for both directions.
(make me think that a good engine for this work is a 2 stroke that's oiled via the fuel)
Power wise, how much do you need? There's the natural drag of the final speed + the compensated drag due to cornering + any drag due to downforce. Doesn't seem like that much overall.
alfadriver wrote: Just "thumbed" though this thread. Didn't notice anyone asking about oiling under constant cornering. I'm not that familiar with how VW's oil and drain, so I'm just wondering how concerned one may have to be if you are constantly cornering at over 1g of load? Or even what the effect on a carburator would be when you have the bowl of fuel basically at an angle. Duly noting that the carb would effectively be slanted at just over 45 deg (at 1g) for both directions. (make me think that a good engine for this work is a 2 stroke that's oiled via the fuel) Power wise, how much do you need? There's the natural drag of the final speed + the compensated drag due to cornering + any drag due to downforce. Doesn't seem like that much overall.
Oiling was asked about, either here or in the initial thread where the skidpad challenge was discussed. And yes its a problem. Flat 4s tend to sling all their oil into their heads during cornering. For autocross use it will be fine but on the skid pad it is an issue I need to deal with, most likely I'll be adding an Accusump to it if I can source the parts cheap enough.
Not sure about the carbs, hadn't really thought about it. I never had any problems with them in formula vees but at the same time I wasn't doing sustained Gs in them either. I won't be putting the FI back on the motor that is certain, there's just too many $$ missing parts to deal with. It might lead me back to putting the Subaru motor in it for the skidpad challenge, it would double the power output too ;)
Noodling the fueling in my brain a little more. I still need to do some investigation but remember these things are usually cruising the dunes and are used to having many steep and awkward angles applied to them as they climb or cross a dune so hopefully it won't be too much of an issue but time will tell.
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