Aerodynamic wind noise suppression - 1951 Mercury custom

[Vman455]

Another thing you might do is experiment with small vortex generators, as are becoming common in the A-pillar area of cars nowadays for noise reduction:


2016 Toyota Prius

[freebeard]

The problem is the shape of the A and B pillars is very old technology. What I am looking for is some kind of temporary deflector either mounted on the front of the car or on the A pillar that will smooth or direct airflow to prevent wind noise. Does anyone have experience with a front deflector that helped make your own car quieter? Thanks.

I'm going to give you the benefit of the doubt, and repost this: Reducing Windnoise / Raingutter Fillers – Gerrelt's Garage

Have you shaved the driprails yet? One of the most beloved cars 'round these parts is Bombshell Betty, here it is at Bonneville:




Perhaps there are some things worth noting there that you might care to discuss?

[mercguy1951]

Thanks for the Gerrelt's Garage link! That is a good one. I'll try tape to cover the front drip rail and see if it helps.

[teoman]

Originally Posted by kach22i

The rear view mirror appears to be at "ear height", so the wind noise will be at ear height.

Yea, between the hinged vent window and the side view mirror location there is going to more noise than a modern vehicle.

This YouTube video below claims cleaning you rubber door seals helps. Does your car even have rubber doors seals? If it does, what shape are they in?

One of the comments in that video said this:


On my S-10 I tore one of my rubber door seals forcing it open after some freezing sleet, I'm used to the extra noise now but in the winter I get a jet of cool air passing through it if the wind is just right.

Thanks for the video.

I will do that soon.

[aerohead]

It's possible that the entire side of the greenhouse is embedded within the turbulence of the side-view mirror.
This illustration gives a sense of the magnitude of a mirrors turbulent wake as a function of fineness ratio (the length divided by the width ) and associated drag coefficient

The drip rail is no doubt triggering separation,and the vortex outside the glass may resonate parts of the car at some natural frequency,plus octaves of that frequency.

High end modern cars spend a lot of time in anechoic chambers to fine tune the greenhouse area for low noise.They're even using double-pane glass for a more quiet ride.

Maybe some painters tape and cardboard can isolate the noise source,then you can think of an aesthetic fix.
Beautiful car!!!!!!!!!!!!!!!!

[Frank Lee]

I'd remove the mirror(s) and go for a spin.

And double check the door seals.

And window seals.

I'd think it'd be one or both of those.

No, I would not re-engineer the pillars or anything else except for maybe the mirrors if they are the culprits.

I doubt deflectors are where it's at. Same with anything at the front of the car.

[kach22i]

I just found this image.

March 2017
An Introduction to Automobile Aerodynamics
More than Meets the Eye
By Joseph Katz, PhD
https://mechanixillustrated.technica...-aerodynamics/

A closer look at the flow near a road car may reveal more areas with vortex flow, and as an example, the A pillar area is shown in Fig. 7e. The main A pillar vortex is responsible for water deposition while driving in the rain, and in addition, the rear view mirror creates an oscillating wake. This vortex flow near the rear view mirror is also responsible for vortex noise during high speed driving.

Looks like a good article.

[freebeard]

Consider a stethoscope. Or, for new school, a smartphone tachometer app.

If you solve the immediate problem, are you done? Would you be willing to go further down the rabbit hole? What's underneath, an Art Morrison chassis? A mid-80s GM 'skateboard'?

One thing you could do without affecting the old school look is add a KERS.

[mercguy1951]

I use a small diameter rubber hose as my stethoscope. I'm out of town right now, but when I get back to the Merc I want to try to add some small blocks and tape on the A pillar to see if I can smooth the air flow around it. Also I may try to tape the back of the front door glass to prevent air leaking into the door and see if that helps. I'll try removing the mirror too.

The problem with these old cars is that all the glass is inset deeply into the body. The windshield has bulging rubber and stainless trim around it too. I wish we had access to a wind tunnel we could use to work on these problems

[elhigh]

Back in the day my dad had a 1970 SAAB 96, and one thing I remember noticing on it were these corner wind deflectors in the windows:


SAAB, being an airplane company, I expect had a pretty good handle on turbulence and wind noise. Something similar may make a big difference on your Merc. If nothing else it could move the point of the worst noise generation further away from your ear.