Thursday Twister: NACA Duct Tales
Welcome back to the Thursday Twister, a feature that is as much about breaking the rules as it is about ruing the breaks. Last week, we had a considerable turn out with readers identifying cars that feature the Hofmeister kink with a rather sizable list at the end, great job to all. This week, we are looking for factory cars that sport the aerodynamic inlet known as the NACA duct.
Getting airflow from a surface parallel to flow lines without creating a bunch of drag-inducing turbulence was an issue faced by the U.S. National Advisory Committee for Aeronautics (NACA), which was the predecessor to NASA. A bunch of suit/glasses wearing engineers with slicked back hair determined the optimum shapes for these inlets and published them in 1945. These shapes became obsolete for nearsonic and supersonic aircraft, but they were perfect for reducing drag on cooling inlets for racecars.
Today, lets put together a list of all the NACA duct equipped factory cars.
My entry is the 1969 Shelby Mustang, which features a hood festooned with NACA ducts because they rule.
Standard contest rules are as follows:
1. Only one car per comment (be sure to hit the refresh button on your
browser before you post in case someone else has posted since you loaded
the page). Do not nest the replies, just reply to the main post — if
you reply to someone elses comment it should be in reference to his
comment and not a new submission.
2. You can post again, but only after someone else posts another car.
3. The contest will end at Sunday, March 22nd, 4pm PST.
4. One submission per generation of car.
5. Each car must be a running/driving car (no clay model prototypes) and
at least two must have been built of that particular car (no one-offs).
6. No anonymous submissions — pick a name with the Name/URL dropdown.
7. This is not for just any old hood scoop or for aftermarket aberrations. They must have the telltale NACA converging/diverging profile. They can be 1/2 NACA (NA?) like the fender scoop on a Renault5 Turbo.
Ready….Set…Post!
Lamborghini Espada
[img] autos.ca/wp-content/uploads/2015/03/Lamborghini-Espada-JP-01-645×420.jpg[/img]
Do the ducts have to be functional?
Nope. They just have to look like they are functional! 🙂
Does it have to be on the hood?
Can it be a truck?
Can it be reversed?
Can the car be mid-engined?
Are we counting louvers, portholes, blower scoops and other whatnot as NACA ducts?
Is this okay?
[img] images.spaceref.com/news/2008/rubberDuck.nasa.jpg[/img]
No, yes, yes, yes, no, yes.
Thanks! Just to clarify, I'm sure for nobody but me…they don't have to be on the hood, it can be a truck, it can be reversed, it can be a mid-engined car, we're not counting anything that doesn't resemble the NACA duct directly (tricky one there because the B-pillar ducts on the Stratos are not very NACA-like and yet I've seen them referred to as such several times) and a NASA duck is rather Daffy.
Callaway TT
[img] carpictures.com/pics/full/06KRM212310830A/Chevrolet-Corvette-Callaway-Twin-Turbo-1987-06KRM212310830A.jpeg[/img]
Alfa Montreal.
Nissan GT-R
Countach
[img] farm9.static.flickr.com/8281/7759634030_7615b8e5c9.jpg[/img]
so damn pretty
Man, I forgot how clean those early ones were.
Hyundai Genesis Coupe
924 with a snail attached to the exhaust
[img] 356-911.com/post1974/modernspottersguide/spotterspics/924turbos1.jpg[/img]
TVR Vixen
[img] tvr.at/grafiken/vixenv8_n.jpg[/img]
Viper
oh come on, no picture?
[img] image.superstreetonline.com/f/9067736/0612_turp_12z+2002_dodge_viper_gts+left_front_view.jpg[/img]
Nope. No pictures unless requested to speed page loading. I will happily post an image upon request.
F40
[IMG] c1.staticflickr.com/5/4154/4992269441_7422c57707_z.jpg[IMG]
Holden Monaro
[img] c1.staticflickr.com/1/182/409657968_c05c681ee3.jpg[/img]
Datsun/Nissan Z Turbo (280 and 300 for example)
[img] carphotos.cardomain.com/ride_images/3/757/961/26890480008_large.jpg[/img]
You like the pictures, admit it! I remember back in the dark days when DT didn't have that function available to users. Some fool talked El Jefe into it…and yet, no street cred for HIM!
Illiterate 🙁
You've figured me out; whenever I go to a restaurant, I order my food from the pictures on the menu!
Fancy shmancy! I just take whatever slop they wardens are dishing out. I particularly like…
[img] cdnpix.com/show/imgs/f70d2296a5bf73a2932ce0244323cab7.jpg[/img]
Lancia Stratos
[img] media.cms.windingroad.com/autos_db/uploads/image/lancia-stratos.jpg[/img]
Alfa Montreal
[img] details-of-cars.com/wp-content/uploads/parser/Alfa-romeo-montreal-1.jpg[/img]
Duplicate of Chris Keen.
@##@#@$ no picture posting people and their hard to see entries………
GM F-body (Camaro, Firebird, etc.)
All of them!? They're so radically different!
Do you include the 2nd gen Firebird's fender extractors?
And the 3rd gen IROC hood ducting too?
That's how this game works. That's why we don't have the C1, C2, C3….C1512 Corvette as acceptable answers. If we listed every edition of a model that included whatever the Twister was for, it would be a bloody mess. The differences between the F-body cars was never much more than a swip-swap of bits and pieces, minor body styles and badges. But you already knew that.
Okie dokie 🙂
And yes, as a previous owner of a '79 Trans Am WS-4, the fender extractors were the first thing I thought of when I saw this week's Twister!
It's good to hash these things out, if in doubt. Makes it easier to come up with the correct answers. I invariably toss away some great cars at the beginning of every Twister because I'm not quite clear what is being specified. If El Jefe continues to offer them up, I have the feeling these things will become clearer and clearer. Look how far we've come in just the past few!
Plus, you're helping and educating other people in the process. Asking questions is something that our culture has a sickening tendency to frown upon. Which is horrific. We gotta break that habit, each and every one of us. There isn't a single one of us that knows everything, despite our twenty gallon hats.
[img] ecx.images-amazon.com/images/I/41X-PGa%2B5yL._SX342_.jpg[/img]
Bugatti Veyron
[img] autozine.org/Archive/Bugatti/new/Veyron_SS_2.jpg[/img]
Ruf Yellowbird
[img] files.conceptcarz.com/img/porsche/yellow_bird_06.jpg[/img]
Holden Monaro
[img] my-car-picture.com/image-files/70-holden-monaro.jpg[/img]
those are just a hood scoop, not naca ducts, no?
yeah. probably. rescinded.
Tesla Roadster
[img] autotrader.co.uk/EDITORIAL/editorial_images/non_imported/tesla_roadster_front.jpg[/img]
McClaren F1
I think we are confusing NACA ducts with basic scoops/intakes. Here is the distinct shape of a NACA duct….it tapers from narrow to wide at the point of the intake. Maybe the F1 had NACA ducts, but the ones I recall (roof and hood) were just basic air intakes.
[img] formula1-dictionary.net/Images/naca_duct.jpg[/img]
El Jefe? What say you to Fleetwood's excellent query? Shall we just keep on truckin' playin' fast and loose with the challenge? Or do we get nit-picky? Seems like fun either way, to me!
Nit-picky. We aren't just counting any-old scoop here because the list would go on forever, they have to have that tell tale NACA converging/diverging shape and be designed for airflow needs. And YES, ones on the bottom of cars count, but you'd better find a picture.
Hallelujah
[img] hogansheroes.weebly.com/uploads/1/5/9/0/1590348/8766018.jpg?315×235[/img]
Amen. Above questions continue unanswered, though…
Bite tongue; answers have been answerfied.
Also, F1 accepted according to El Jefe's specs. A couple of times, in fact.
Renault 5 turbo
[img] images.pistonheads.com/nimg/24344/Car-2-L.jpg[/img]
Subaru Impreza (WRX, STi, etc.)
If we're just gonna bastardize this into "any old hood scoop will do", here's my shark jumper.
[img] imganuncios.mitula.net/2008_toyota_tacoma_double_cab_trd_sport_96635313707516559.jpg[/img]
Gracias…feel free to delete this "attempt to make a point" post. 😉
FTB, I asked whether trucks were fair game at 11:16AM PST. Your point about the validity of a NACA duct is also valid. But since neither has been defined, your Tacoma seems like fair game to me!
Hoodscoops will be another day — lets stay focused on ducts designed to maximize air flow without creating too much turbulence in the surrounding flow region. They should look like this.
[img] recumbents.com/wisil/nacaduct/naca-ramp-plan.gif[/img]
Oops, there's your clarification Fleetwood.
So the GT40 doesn't count?
Citroen 2CV under-hood air extractor. In fact, it is kind of an inverse application of the principle. The classic two-dimensional taper creates a low pressure zone, like a normal NACA duct, but they use it to draw hot air from under the hood over the top edge of the duct. And it works!
[img] ami-2cv.com/media/blog/chassis.05.jpg[/img]
Nissan GTR
[img] nissanusa.com/st/nissan/images/assets/2012/gtr/features/12TDI_GTRshop021.jpg[/img]
Plymouth Barracuda
TVR Vixen
[img] tvrblog.com/wp-content/uploads/2011/09/tvr-vixen_tvr-blog-32333.jpg[/img]
arrrrrrgh……..duplicate. sorry Sean
Hey guys, this is going fast and furious so double check that your excellent submissions aren't already posted!
Consulier GTP
Lamborghini Jarama
[img] 3.bp.blogspot.com/-kaWb_801QoE/UZTfnUowG7I/AAAAAAAAARY/kTpuBQyMXHY/s320/lamborghini-jarama-02.jpg[/img]
AM DP216 – look at that face!
[img] upload.wikimedia.org/wikipedia/commons/b/b1/A_Aston_Martin_DP215_head.JPG[/img]
Audi TT RS, Mk2 A5 Chassis.
[img] lz7w.com/gallery3/var/albums/ttrsmods/oilchange/IMG_9027.jpg[/img]
Does the B5 A4 1.8T Quattro undertray count? Similar "vintage" same manufacturer.
It would, but you need to post it in a separate comment and if you wouldn't mind posting a pic for my old, tired eyes I would be much obliged!
I guess we all need to post pics of underbody aero with NACA ducts.
Linked image.
Guess the part is the same between the B5 A4 and the B5 Passat. I saw some B6 and B7 A4 stuffs there too but I'll let someone else figure out the picture thing.
Ferrari 512 BB
[img] almuro.net/sitios/Mecanica/imagenes/coches/ferrari_512_bb_1976.jpg[/img]
Mitsubishi Evo
Ferrari 288 GTO Evoluzione
[img] a406.idata.over-blog.com/420×280/4/15/62/69/Competition-1976-a-1985-Vol-2/1985-1986-Ferrari-288-GTO-Evoluzione-7.jpg[/img]
5 made, 4 in private hands…
Ferrari 208/308
I was on the fence on that one. Is that really a NACA duck?
There are so many scoops and wings and such, I can't either. But I'd vote yes on at least the lower ones. Eh, but whatever. It is, it isn't…it's a kerfuffle!
[img] avto-russia.ru/autos/ferrari/photo/ferrari_208_4.jpg[/img]
This comment has been removed by the author.
I only included the 308 because of its relationship to the 208. If you think that one's out, that's fine by me. But give me my tiny red 208 dancer, I beg of you!
[img] spacetimestudios.com/attachment.php?attachmentid=16922&d=1348224151[/img]
And of course, the argument could be made that if the ducts behind the doors of the Stratos are a-okay, then the Dino 308 GT4's ducts in a similar location would most likely have to be accepted.
[img] allcarcentral.com/Ferrari/Ferrari_Dino_308_GT4_1972_concorso-it_2007_BBB_0155.jpg[/img]
So the 208 Turbo pictured above has NACA ducts down in front of the rear wheels. I seem to remember that they duct air to oil coolers that the naturally aspirated 308 didn't need. The 'torpedo tube' ducts atop the rear wheel arches are not NACA ducts.
Then you're voting that the 246 Dino not being included? Don't forget that El Jefe specified that they needn't be functional.
Ferrari 250 GTO
If not functional – 56 Continental Mark II ??
[img] 21k06y2lopid12br011g3o3msqh.wpengine.netdna-cdn.com/wp-content/uploads/2013/05/1956-Lincoln-Continental-MKII-800×373.jpg[/img]
That is a functional duct inlet for the rear mounted AC system.
Aston Martin V8 Zagato
Nissan GTR
[img] gtrblog.com/wp-content/uploads/2008/09/tecnocraft-002.jpg[/img]
Ferrari 550
Lamborghini Diablo SV
Bond Bug
Lamborghini Espada
[img] static.cargurus.com/images/site/2009/07/17/13/23/1968-lamborghini-espada-pic-46144.jpeg[/img]
Isuzu Impulse Turbo RS
TVR 2500M
Isdera Imperator
1976 Corvette
Pontiac GTO (1973)
Isdera Commendatore 112i
Renault Clio
Mercedes-Benz 300 SL "Gullwing"
Picture requested, please. Thanks!
[img] static0.bornrichimages.com/wp-content/uploads/s3/1/2012/09/19/a_1955_mercedes_benz_300sl_alloy_gullwing_to_fetch_up_to_32_millions_qyez3.jpg[/img]
Thank you!
Lotus Elite
Lotus Elise
Alpina B12
Just in case you were wondering…
[img] alpina-archive.com/images/cars/1542-01.jpg[/img]
Always loved the 8-series. Best Bimmer ever!!! (of the semi-modern ones, at least)
Alpina B6
Picture of NACA duct please. Thank you!
Technically a reverse-NACA duct.
[img] livetradingnews.com/wp-content/uploads/2014/06/BMW_ALPINA_B6_xDrive_Gran_Coupe.jpg[/img]
Bugatti EB110
Fiat 500 Abarth. Before you ask for a pic, here's one 🙂
[img] pictures.topspeed.com/IMG/crop/201309/fiat-500-abarth-and–7_600x0w.jpg[/img]
Can't say I'm seeing the NACA duct? You're not talking about the rear corner bumper vent are you?
Yes
TRDsmith, my buddy…you KNOW you're AWESOME, right!?! You are, no doubt about it. But I think you might be possibly spinning your wheels (hey, a car joke, whodathunkit?) just a tad bit. You might consider scrolling up and reading all of the discussion about what is and what isn't an acceptable NACA duct for this Twister, according to El Jefe. If it were up to me, I'd include stuff like the bitchin' Abarth 500 — ooh, how I wish it were so because I have a mess of super cool cars with ducts and scoops and shtuff like that I want to include. But my wishful cogitating won't make it so. Just don't want to waste your excellent detective work here…!
Great. Now you're gonna hate me. Scheisse.
Ligier JS2…might be stretching a bit here. You decide.
[img] c1.staticflickr.com/7/6021/5923271504_9289c605c5_z.jpg[/img]
Volvo XC90 Skid plate / undertray.
Picture please! I looked but didn't find an image with a NACA duct. But I probably just missed it!
A quick googling for 8622717 Volvo brings it up. It's called a protective plate. Couldn't find a good image that wasn't over the size limit but here is a link to a page with an image.
It appears to be an accessory made by Volvo. Apparently, it's a very bad thing to put it on some editions as it blocks cooling. But it exists as far as I can tell and I'm adding it to the results list, unless anybody has an objection. Thanks for the link, RyanM and good job!
AND unless I'm going blind (likely), you found the ONLY crossover on the list so far! Though it appears everybody has jumped ship and are busy discussing the color orange. Shoot. I had more.
Jankel Tempest
I'm curious when the very first NACA duct appeared on a production car. I found this, but I'm not so sure it's true.
The extra drag caused by raised or extended scoops can be significant, so back in 1945 the National Advisory Committee for Aeronautics (the predecessor of NASA) developed a type of submerged scoop for fast-jet aircraft, now known as a NACA duct. Rather than protruding above the body, a NACA duct sits below the surface with a gently sloped ramp and curved walls. (The curvature of the duct’s sides creates vortices that deflect the boundary layer away from the faster-moving air entering the scoop.) A NACA duct creates less drag than a protruding intake, although it doesn’t allow a high volume of airflow. The first use of functional NACA ducts in a production car was probably the 1969 Shelby Mustang…
Where are all my Twister pals? Wait. That sounded weird.
Bueller?
I'll take the bait that you set elsewhere on Daily Turismo; Porsche 986 Turbo S.
Let's boogie, bruddah; Pontiac Grand Am from the year 1973.
Bring it; Ford Falcon XA.
1987 – 1995 porsche 928. You say "whaa???" Yes, it be true…. It has not just 1, but 2 true fully functional NACA ducts…
They're underneath, aren't they?
Yes. Under engine aero panel. Direct cool air to the exhaust manifolds. Way to be on the ball. 🙂
Sounds good to me – thanks!
928motorsports.com/parts/images/Bellypan/NewBottomTray2.jpg
Dodge Durango Shelby SP360…SUV!
[img] autopartz4u.co.uk/image/cache/data/AUDI%20A6%20BODY%20UNDER-500×500.JPG[/img]
Audi A6
Hamann Mercedes-Benz G65 AMG Spyridon…another SUV!
[img] db.carbuzz.com/images2/300000/1000/100/301137.jpg[/img]
[img] img.auctiva.com/imgdata/1/5/7/7/8/2/7/webimg/672731061_tp.jpg[/img]
VW Golf
Pagini Zonda
I believe this image of the Audi R8 is too large, so I will hyperlink it.
Kodiak F1
[img] crunchpost.com/wp-content/uploads/2010/08/7-Kodiak-F1.jpg[/img]
Leader Board
1. K2 Mystery Car (28)
2. Gianni (4)
3. Sean T (4)
4. Bolo (4)
5. TRDsmith (3)
6. FTB (3)
7. Vince (2)
8. Sean Scott (2)
9. Bobinott (1)
10. Johnny16v (1)
11. Chris Keen (1)
12. RyanM (1)
13. pcar928gt (1)
Leader Board with Rule Benders
1. K2 Mystery Car (30)
2. TRDsmith (7)
3. Sean T (5)
4. Gianni (4)
5. Bolo (4)
6. FTB (3)
7. Sean Scott (3)
8. Bobinott (1)
9. Johnny16v (1)
10. Chris Keen (1)
11. RyanM (1)
12. pcar928gt (1)
Results
1. Alfa Romeo Montreal (Chris Keen)
2. Aston Martin V8 Zagato (K2 Mystery Car)
3. Audi A6 (Bolo)
4. Audi R8 (Bolo)
5. Audi TT RS (Vince)
6. Bond Bug (K2 Mystery Car)
7. Bugatti EB110 (K2 Mystery Car)
8. Bugatti Veyron (Gianni)
9. Chevrolet Corvette Callaway TT (Sean Scott)
10. Citroen 2CV (Bobinott)
11. Consulier GTP (K2 Mystery Car)
12. Datsun/Nissan Z Turbo (K2 Mystery Car)
13. Dodge Durango Shelby SP360 (K2 Mystery Car)
14. Dodge Viper (K2 Mystery Car)
15. Ferrari 208/308 (K2 Mystery Car)
16. Ferrari 250 GTO (K2 Mystery Car)
17. Ferrari 288 GTO Evoluzione (Gianni)
18. Ferrari 512 BB (Gianni)
19. Ferrari 550 (K2 Mystery Car)
20. Ferrari F40 (Johnny16v)
21. Ford Falcon XA (Bolo)
22. Ford GT40 (K2 Mystery Car)
23. Ford Mustang (Vince)
24. GM F-Body (K2 Mystery Car)
25. Isdera Imperator (K2 Mystery Car)
26. Isuzu Impulse Turbo RS (K2 Mystery Car)
27. Jankel Tempest (K2 Mystery Car)
28. Kodiak F1 (K2 Mystery Car)
29. Lamborghini Countach (Sean T)
30. Lamborghini Diablo (TRDsmith)
31. Lamborghini Espada (K2 Mystery Car)
32. Lamborghini Jarama (Gianni)
33. Lancia Stratos (Sean T)
34. Lincoln Continental Mark II (Sean T)
35. Ligier JS2 (K2 Mystery Car)
36. Lotus Elite (K2 Mystery Car)
37. Lotus Elise (TRDsmith)
38. McClaren F1 (K2 Mystery Car)
39. Mercedes-Benz G65 AMG Hamann Spyridon (K2 Mystery Car)
40. Mitsubishi Evo (K2 Mystery Car)
41. Nissan GT-R (K2 Mystery Car)
42. Pagini Zonda (K2 Mystery Car)
43. Plymouth Barracuda (K2 Mystery Car)
44. Pontiac Grand Am 1973 (K2 Mystery Car)
45. Pontiac GTO 1973 (K2 Mystery Car)
46. Porsche 924 Turbo (Sean Scott)
47. Porsche 928 (pcar928gt)
48. Porsche 968 Turbo S (Bolo)
49. Renault Clio (K2 Mystery Car)
50. Renault 5 Turbo (FTB)
51. Ruf CTR “Yellowbird” (FTB)
52. Tesla Roadster (FTB)
53. TVR 2500M (TRDsmith)
54. TVR Vixen (Sean T)
55. Volvo XC90 (RyanM)
Rule Benders
1. Alpina B6 (TRDsmith)
2. Aston Martin DP216 Prototype (Sean Scott)
3. Fiat 500 Abarth (TRDsmith)
4. Holden Monaro (Sean T)
5. Hyundai Genesis Coupe (K2 Mystery Car)
6. Isdera Commendatore 112i Prototype (TRDsmith)
7. Mercedes-Benz 300 SL Gullwing (TRDsmith)
8. Subaru Impreza (K2 Mystery Car)
9. Toyota Tacoma (FTB)
The NASA duck says, "Thanks for playing – this one was a fun one!"
[img] cdn100.iofferphoto.com/img/item/624/389/71/pin520.jpg[/img]
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