Author Topic: BBarn and Robfreys A/BG liner  (Read 26837 times)

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Offline willieworld

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Re: BBarn and Robfreys A/BG liner
« Reply #75 on: January 08, 2010, 01:09:31 PM »
hhhhhhhhhhuuuuuuuuuuuggggggghhhhhhhhh              willie buchta
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Offline dw230

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Re: BBarn and Robfreys A/BG liner
« Reply #76 on: January 08, 2010, 01:14:25 PM »
The tape is to seal the gap between the bolt in panel and the chassis.

DW
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Alcohol - because no good story starts with a salad.

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Offline Stainless1

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Re: BBarn and Robfreys A/BG liner
« Reply #77 on: January 08, 2010, 03:53:42 PM »
The tape is to seal the gap between the bolt in panel and the chassis.

DW

Like most streamliners they are attempting to keep the salt confined to the wheel well salt boxes.  The metal tape is better than duct tape for the job.
Stainless
Red Hat 228.039, 2001, 65ci, Bockscar Lakester #1000 with a little N2O

Offline willieworld

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Re: BBarn and Robfreys A/BG liner
« Reply #78 on: January 08, 2010, 06:23:40 PM »
enlarging the pic i can see that the only tape in the pic is right below eag on the front wheel rim covering  a wheel weight ---which i dont think is required by the scta---i think its done to keep salt from building up against the weight and causing a imbalance problem                     willie buchta
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Offline wobblywalrus

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Re: BBarn and Robfreys A/BG liner
« Reply #79 on: January 09, 2010, 01:11:04 AM »
What is metal tape?  Where do you get it?

Following this build is interesting.   

Offline John Burk

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Re: BBarn and Robfreys A/BG liner
« Reply #80 on: January 09, 2010, 01:30:48 AM »
McMaster Carr

Offline hitz

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Re: BBarn and Robfreys A/BG liner
« Reply #81 on: January 09, 2010, 01:42:40 AM »
Nate Jones put aluminum tape over the weights when he shaved and balanced the tires on the lakester. I thought it was an extra precaution to keep the weights on.

Willie-- I like your thought on the tape keeping the salt from lumping up on the wheel weights.The aluminum tape looks like something that was made for sealing ducts. Maybe it's duct tape for a street rod.

Harv

Offline Stainless1

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Re: BBarn and Robfreys A/BG liner
« Reply #82 on: January 09, 2010, 09:43:37 AM »
In airplanes we called it speed tape, it's good to about 600 MPH or so.   It is also available at Home Depot, in a slightly thicker version that is duct tape.  The HD version is only good to about 450....

go to the basement, look at the furnace, you will likely see some  :-D
Stainless
Red Hat 228.039, 2001, 65ci, Bockscar Lakester #1000 with a little N2O

Blue

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Re: BBarn and Robfreys A/BG liner
« Reply #83 on: January 10, 2010, 04:56:19 PM »
The drawing shows side by side. I think they should be in-line, slightly off set actually, not on the same center line.

For example check out Speed Demon, Neb III, Al Teague, etc.
DW
I can certainly appreciate the history of some of these teams having success with the staggered arrangement, but I am very uncomfortable with it from an aero standpoint.  The exposed sections of the tires will combine their respective flow fields and at some point this will become a significant aerodynamic rudder.  Because they are staggered, the rudder effect would then have to be trimmed out with steering in the other direction.

I think they have not gone fast enough yet for this to be an issue.  Dynamic force (and the resulting psuedo-rudder force) increases by almost 60% from 400 mph to 500 mph; so we'll see.  Personally, I would not "design in" a potential failure mode like this.  TSSC did and suffered yaw transients that required lock-to-lock corrections at over 500 mph.  OK, we'd all love to get going that fast; but I still wouldn't install a pretty obvious handling mode like this.

The in-line salt-spray-into-trailing-tire issue must be solved for this design anyway:  the rears require it.  Whether this is a fixed or movable fairing (to account for tire growth) in front of the second tire requires data.  I suggest someone run across some sand or dirt with the same amount of wheel spin as LSR (5 to 10%) and video the "spray".  Do it with a street car, race car, AND your wife's FWD minivan!  I have heard dozens of theories about this effect and IM<<<<HO, it's all speculation without data.  Show me some close-up tire ejecta video at different speeds, with different surfaces, and different vehicles and let's design to the data.  The video I've seen of Bonneville is simply not high enough resolution in this area to design a new car from.

Lots of "old salts" (much respect and no pun intended) have decades of experience on where the salt ejecta ends up on the wheel wells.  Instead of assuming that this build up was caused by things we haven't video'd, let's get some video and corellate it to the salt build up.  Better understanding and designs for all will result.
« Last Edit: January 10, 2010, 05:08:51 PM by Blue »

Blue

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Re: BBarn and Robfreys A/BG liner
« Reply #84 on: January 10, 2010, 05:36:20 PM »
Design consideration #2. - Let the comments fly...








Put turbos at the back of the engine compartment by the tranny; there's more volume there.  Put the radiator, fuel cell, and intercooler in front of the engine at the widest point.  Cockpit between the front wheels and engine compartment;  this, again, it is to keep the widest things in the middle like JHN says.  Bump the cross section around the engine to include decent manifolds.  Lots of power and reliability is lost in current designs from inadequate manifolds (especially in the 400 mph club.  I apologize for this, we all need to look at other motorsports to see what optimized turbo intake and exhaust manifolds look like when people have spent millions of dollars on a few percent gain.  Specifically look at Indy car.)

The "frontal area" does NOT matter.  #1 is separation (no blunt tails), #2 is wetted area (smaller is better, look at Wheeler), #3 is laminar run.  I hope I have time this year to write an article on this for the LSR community that explains these issues in terms that will help everyone design better cars.  Everyone who posts here is more than intelligent enough and experienced enough to understand the truth about aero vs. the myths.  But it's not intuitive, and there's a lot of bad information out there.

Yes, neck down the sides of the body just in front of the wheel fairings, then go straighter aft over the diff's, then taper to a point.  Yes, a point.  Any, and I mean ANY blunt tail will create more drag than the entire rest of the car.  Tandem (side-by-side) fronts will be higher drag and harder to fair than in-line;  solving the steering will be the other way around.  I'm working on that.

Last, with all due respect to the records and speeds established by the Costella and Costella-type designs, drag build up calculations show all those flat bottoms and blunt tails are in fully separated flow.  To go faster, we need to get back to what makes downforce with the least drag, not the most:  i.e. wings, not ground effects.  Good wings can produce 5 to 30X the downforce-to-drag ratios of any ground effects.  They are less sensitive to ride height and do not cause lifting when the car gets out of shape.  Good wings have a 5 to 30:1 L/D;  ground effects are lucky to hit 1:1.

To any who wish to use ground effects, I urge you to read "Race Car Aerodynamics" Joseph Katz ISBN 0-8376-0142-8.  Air going under the car is what creates downforce, not the other way around.
« Last Edit: January 10, 2010, 08:13:11 PM by Blue »