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Old 12-06-2012, 06:55 PM   #19 (permalink)
aerohead
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blister

Quote:
Originally Posted by Frank Lee View Post
Aerohead, does that hood blister work? Been able to quantify any effect?
Frank,the short answer is that I don't know.
I was very interested in the GTP-style windshield from the Maurader Lola Mk-4.IF they would sell one to me,and they said 'maybe',it would be $3,000.
It's probably as 'ideal' as I would be able to find in DOT laminated safety glass.
So anyway,the idea,short of morphing on the expensive glass was to create a blister fairing to soften the pressure spike created by the greenhouse erupting up out of the body by altering the angle of attack to the windshield,header,and A-pillars.
Without the blister,the last foot of the hood will tin-can at highway speed.You can just see it displacing up and down.
And the burble at the cowl kills any water dynamics 1/3rd way up the windshield in a rain.So I pretty much new it was 'dead' there.Which is good for ventilation!
And with the blister,the ventilation IS compromised.
In a rain,water is pushed all the way up the blister,so the boundary layer is very active upon it.And rain which makes it to the glass is actively fanned-out by the airstream.
One definite liability is that the lower portion of the glass remains dry in a rain which is tough on the wipers.It's not a hardship,and it can be 'fixed',but I'm busy frying bigger fish.
Without on board instant- results computing capability it might be hard to 'see' a difference in A-B-A on road 'tank' testing.
My 'guess' is that in a wind tunnel,the Prandtl' line of discontinuity would show a modified pathway.If I make it to the A2 Wind Tunnel next year I'll be able to find out with their smoke wand.I hope to put the whole test session on You-Tube so everyone can scrutinize it.
PS I covered the entire 'cowl' area above the blister with cardboard and duct tape to bridge the existing gap at Bonneville.The time slips registered no effect at 105 mph.
In 1990 I had done the same with the CRX and it also showed no change to performance.
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Last edited by aerohead; 12-07-2012 at 05:09 PM.. Reason: add a PS
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COcyclist (12-19-2012), Frank Lee (12-06-2012), radioranger (12-07-2012)