EVO9 Wing Failure/Track Related/ FYI
Apr 11, 2013, 07:46 AM
#49
Evolving Member
But, If there was a way to gain side access to the wing, you may be able to foam the wing. If you could extend the dispensing straw down the full length of the wing & slowly extract it while spraying, you may be able to fully pack-in the foam
Working w/ polyurethane is not easy to work with & it stains & drys very quickly & is almost impossible to remove
Poly U is everywhere, even on what youre sitting on right now
Been working around this stuff all my 24 year career
Bah, someone was gonna do it 
Apr 15, 2013, 04:36 PM
#53
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Gentlemen... I just heard about this post in the general forum and I wanted to add my 2 cents.
First, I only read through the first page. So perhaps it's been covered but...
2 points.
1. Relative wind, and wind shear. If you're traveling at 140 mph into a 60mph headwind, that is obviously a 200mph wind speed. Being that lift/drag charts function on an exponential rate. A wind shift of 100mph when turning a corner can be quite severe. However...
2. Applying a flap to the trailing edge of the wing. It's difficult to tell from the photos, but if there is even a slight variance in how this product is applied, at speed, you could easily create a new pressure center. That pressure center, combined with the type of service a wing on a track would see, vs the type of service a wing on an aircraft would see, and you essentially create a situation where you can have something bending back and forth (think like a pop can tab).
More over, a wing structure is only designed to support a certain load, and I'm doubting HIGHLY, that the stock Evo wing is capable of handling anything over 175mph, let alone with the addition of the factory option gurney flap, or this aftermarket option. Remember, these vehicles were electronically limited to 155mph from the factory.
First, I only read through the first page. So perhaps it's been covered but...
2 points.
1. Relative wind, and wind shear. If you're traveling at 140 mph into a 60mph headwind, that is obviously a 200mph wind speed. Being that lift/drag charts function on an exponential rate. A wind shift of 100mph when turning a corner can be quite severe. However...
2. Applying a flap to the trailing edge of the wing. It's difficult to tell from the photos, but if there is even a slight variance in how this product is applied, at speed, you could easily create a new pressure center. That pressure center, combined with the type of service a wing on a track would see, vs the type of service a wing on an aircraft would see, and you essentially create a situation where you can have something bending back and forth (think like a pop can tab).
More over, a wing structure is only designed to support a certain load, and I'm doubting HIGHLY, that the stock Evo wing is capable of handling anything over 175mph, let alone with the addition of the factory option gurney flap, or this aftermarket option. Remember, these vehicles were electronically limited to 155mph from the factory.
Apr 15, 2013, 05:59 PM
#54
^^^Thanks for the detailed reply
I agree w/you & certainly feel the day I ran was ripe for something like this
It still boggles my mechanical mind that a wing set at a zero angle would see that much load. Enough to snap it with such force as to dent the steel trunk
I agree w/you & certainly feel the day I ran was ripe for something like this
It still boggles my mechanical mind that a wing set at a zero angle would see that much load. Enough to snap it with such force as to dent the steel trunk
Apr 15, 2013, 08:01 PM
#56
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^^^Thanks for the detailed reply
I agree w/you & certainly feel the day I ran was ripe for something like this
It still boggles my mechanical mind that a wing set at a zero angle would see that much load. Enough to snap it with such force as to dent the steel trunk
I agree w/you & certainly feel the day I ran was ripe for something like this
It still boggles my mechanical mind that a wing set at a zero angle would see that much load. Enough to snap it with such force as to dent the steel trunk
To any other aerodynamics people out there... don't hate, I'm trying to simplify simply to convey a point through text.
Moreover, I think many people who add the factory gurney flap, or any after market gurney flaps misunderstand how it actually effects the aerodynamics of the car.
The factory gurney flap was an option only because Mitsubishi realized that the rear end got too light at certain speeds. Rather than redesign the whole wing again, they added a small gurney flap.
When someone decides to add something more though, it's imperative that it is done with an exacting precision, especially if the wing should be used at speed. More to the point, drag, and lift function largely on an exponential curve (see below image), so adding a very small amount will yield SIGNIFICANT benefits at higher speeds. I would argue that, and that alone is the issue at hand here. The fact that your vehicle was likely seeing a relative wind of roughly 200mph, WITH an additional device added. It's highly likely that you simply exceeded the structural limitation of the wing. This is also why many factory wings on a car that can go 155mph look mundane, and the wings on a car that can go 175mph look much more serious.
Sorry to drone. Aerodynamics... heh.
Point C on this chart is where a manufacturer would ideally like their wing to exist. Maximum lift (downforce) and minimum drag. But that happens at a critical speed... obviously.
Apr 15, 2013, 08:03 PM
#57
Apr 15, 2013, 08:15 PM
#58
Thanks again for the aero details
Judging by your screen name, avatar & reference to VOR, you must be a pilot?
Do you fly professionally or recreationally?
EDIT: As you read, I was pushing 140+ in high winds. If Vic (Pirana) chimes-in he was pushing north of 175 mph
Judging by your screen name, avatar & reference to VOR, you must be a pilot?
Do you fly professionally or recreationally?
EDIT: As you read, I was pushing 140+ in high winds. If Vic (Pirana) chimes-in he was pushing north of 175 mph
Last edited by MinusPrevious; Apr 15, 2013 at 08:18 PM.
Apr 15, 2013, 10:14 PM
#60
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Thanks again for the aero details
Judging by your screen name, avatar & reference to VOR, you must be a pilot?
Do you fly professionally or recreationally?
EDIT: As you read, I was pushing 140+ in high winds. If Vic (Pirana) chimes-in he was pushing north of 175 mph
Judging by your screen name, avatar & reference to VOR, you must be a pilot?
Do you fly professionally or recreationally?
EDIT: As you read, I was pushing 140+ in high winds. If Vic (Pirana) chimes-in he was pushing north of 175 mph
Plus, all the good Evo screen names were taken (WHO TOOK MY EIVLEVO!)
Do you have a factory vortex generator? I think it'd be interesting to figure out a vspeed (reference speed) for this wing. Might have to tape some yarn up, and stick the gopro on the trunk on my next track excursion.
If I had to make a recommendation, I'd wager anyone that is REGULARLY driving at speeds of over 125mph with an Evo 9 wing should consider looking for a real wing.
Bear in mind... the stock Evo 9 got thrown around the nurburgring, and I'm sure they were over 130mph. So as long as it isn't prolonged use, you should be fine.