Learn me some about rear spoilers

[j-c-c]

I believe Richie' s car at Sebring was a Roadster, ie no real roof line? And your thinking it was a transfer of technology from his aircraft experience probably has a lot of merit. I believe the correct year is 1961 not 1962 I first mentioned. Its been awhile.

The earlier comment on the Gurney flap is tougher IMO to categorize, as it is applicable to wings, spoilers, and "lips".

Nothing I have read here has made a strong enough case for me to rethink my position on "lips" vs spoilers.

This is an "econo" site, so the mindset of dwelling on drag reduction vs DF, I get that, and by the same token the Sebring Ferrarri spoiler was all about DF and I suspect not drag. Hard to teach old dogs new tricks.

[aerohead]

Originally Posted by j-c-c

I believe Richie' s car at Sebring was a Roadster, ie no real roof line? And your thinking it was a transfer of technology from his aircraft experience probably has a lot of merit. I believe the correct year is 1961 not 1962 I first mentioned. Its been awhile.

The earlier comment on the Gurney flap is tougher IMO to categorize, as it is applicable to wings, spoilers, and "lips".

Nothing I have read here has made a strong enough case for me to rethink my position on "lips" vs spoilers.

This is an "econo" site, so the mindset of dwelling on drag reduction vs DF, I get that, and by the same token the Sebring Ferrarri spoiler was all about DF and I suspect not drag. Hard to teach old dogs new tricks.

I Googled Ritchie Ginther Ferrari and the car I had in mind ran at Le Mans in 1961 and '62 as a 'Targa' body type.The rear upswept spoiler could be imagined as a fixed,speed brake or trim tab.
The 1963 250 GTO Coupe has a roofline that is too fast,would have separated flow,and lift,and the tip of the spoiler would bring the body up to the template and clean air for stability and drag reduction.The teams would attempt a balance between high speed on the Mulsanne Straight,and cornering force on the low speed chicanes.

[California98Civic]

So, I tested a flat rear decklid spoiler last year and the test seemed to reveal a benefit. I am reasonably confident in the results, though conditions are not the most rigorous. Here is the link to the thread here on EM:
https://ecomodder.com/forum/showthre...tml#post602571

[j-c-c]

Very interesting and useful, and i suspect the results are more accurate then you give it credit for.. Since it has no apparent "spoilng" contribution as I see it, and the side plates just keep the upper air from rolling under from the sides, its still in my book at the least, just a "lip".

From a OEM marketing standpoint I suspect, that description does cut it in the sales department as being sexy enough.

[aerohead]

Originally Posted by j-c-c

Very interesting and useful, and i suspect the results are more accurate then you give it credit for.. Since it has no apparent "spoilng" contribution as I see it, and the side plates just keep the upper air from rolling under from the sides, its still in my book at the least, just a "lip".

From a OEM marketing standpoint I suspect, that description does cut it in the sales department as being sexy enough.

Probably,anything which sequesters a low pressure regime (turbulence and attached,counterrotating longitudinal vortices) away from the upper body,or provide for flow reattachment would technically qualify as a 'spoiler,' if it reduces unwanted lift,and lift-related drag.

[JulianEdgar]

Originally Posted by 67-ls1

I'm now driving my 66 Chevelle eco project and am getting over 30 mpg.
Im working on a front air dam now and will probably add a small splitter to the bottom of it.
is there any kind or a rear spoiler I could add to the rear of the trunk lid to help airflow off the back?
Either a small wickerbill or a flat extension. Which would be better for economy? I don't need downforce.
And how do I calculate the overall height or length and the fore-aft placement along the trunk lid?
Thanks,

Why not just do some testing?

Is there attached flow on the rear window and trunk? Tuft testing will show you that.

If not, a flat extension spoiler will do nothing. And if not, to gain flow reattachment, you will need to lift the trailing end of the trunk (eg by a raised spoiler or 'wing' (that isn't).

Throttle stop testing (other thread) will also show you if you're managing to get a decent drop in drag (ie above a few percent).