Automotive Aerodynamics Ep. 4: Jaguar E-Type XKE

In this newest episode I talk about the aerodynamics of one of my favorite cars, the E-type Jaguar. Experiments were performed using a 1/18 scale vehicle model to determine the behavior of the flow around the open-top and hard-top models.
For more, see my channel or visit GraysGarage.ca

[@RotaryRebuilder]

Hope you guys like the video, stay tuned for more to come soon!

[@sl270703]

Some one posted this on CarThrottle. Now im hooked, awesome informative videos! BTW, It would be very interesting if you could talk about active aerodynamics or show a water tunnel video of a Huayra or an F1 DRS

[@overcastfriday81]

All these videos are great -- good job! Finally an alternative to the wind tunnel tests with idiots holding a smoke wand so high, any car would look good.

[@bevlad100]

+GraysGarage Hi, great video, really informative. I guess you get loads of requests for particular cars to study but if you could look at the Datsun 240z I think it would be quite interesting to see the difference between the standard car and the BRE version with the large chin spoiler, covered headlights and duck tail spoiler at the back.

[@alecmillea4539]

It would be amazing if you did this test with a classic mini 1.533m^3 frontal area and a coefficient of drag at an astonishing 0.51. it would be fantastically interesting to see the unbelievably bad areo dynamics at work and I think quite interesting if you could use a 3d printer to make little scale pieces of placlstic to try and see what will improve the airflow. I'm sure if you did a whole series like this with model cars that little "wind tunnel" and attempting body mods to improve the aerodynamic problems and possibly even try downforce creating mods to show us what that looks like. I know it's a huge amount to ask and I don't expect a response but I think it could really launch this channel. Oh and if you wanted it to be really succesful I'd advise a decent slow motion camera to provide excellent footage!!! Just trying to help!

[@weareallbeingwatched4602]

The design of this vehicle was informed by WW2 and WW1 aircraft, as well as race + land speed vehicle design. The open top separated flow air pocket roof is quite deliberate.

[@AlexLutzC]

Great, informative videos. Thanks a lot for your hard work. Can’t wait to see more!

[@johntechwriter]

For E-Type fans and ex-owners like me, this was a fascinating and educational journey into the real-world aero of a car that, in its time, looked more streamlined than any other. The host concludes the E-Type, even the more slippery coupe, in fact had poor aerodynamics, with a drag coefficient exceeding 4.0, which is very poor indeed. I have trouble reconciling this with the knowledge that this car was designed by Malcolm Sayer, an aerodynamicist whose background was in aircraft design. He used mathematics to calculate the E-Type's curves, the goal being optimal aero for optimal top speed. His next project, the D-Type, won LeMans against more powerful opposition by way of reduced drag, which enabled the D-Type to achieve 192 mph on the Mulsanne Straight. But I think there is not necessarily a contradiction here. Modern aero science shows us the E-Type coupe is a combination of good and bad aerodynamics, and its final appearance went beyond pure science and took into account the aesthetic standards of the day. Skip forward to the present, when truly excellent aero is exemplified by Toyota's Prius. This evolution in car design is consistent with the transition of the automobile from being an object of art, to its eventual status (once self-driving and electric power are factored in) as an impersonal transportation module. Future generations may never understand our love of cars: their beauty, their power, their handling, their personalities. Perhaps the most effective way to get across to them what they missed during the golden age of personal transportation would be to present them with a few photos of the E-Type. If this car's design doesn’t raise their pulse, I fear that our descendants will also be unaware of many other things that make life worth living.

[@asdreww]

Been waiting for the next video... fantastic. keep them coming!

[@RotaryRebuilder]

glad you liked it! next up will be nissan skyline

[@areitu]

Keep up the good work! You've got yourself another subscriber here! Thanks for taking the time to make these videos and explain what's going on in each one. After watching a few of these videos, I can see why some modern cars are shaped the way they are, and how unintuitive aerodynamics can be at first glance. If nobody's asked yet, or you're still trying to think of another car to visualize, I'd love to see one for a square-shaped car, like a Subaru Forester, or a pickup truck.

[@overcastfriday81]

With the improvised hardtop, it resembles a datsun 260. The coupes were not sleek. When you have a baby turtle humping a banana, you'll probably capture the essence of the coupes

[@BuzzLOLOL]

Yeah, only liked the roadsters... would never own a coupe...

[@jerrymouton]

After watching your first episode testing the 4 Japanese cars, you are kind of struck by Kamm's discovery: that it is better aerodynamically to chop off the rear end than to stretch it out. Even though they all have significantly more turbulent wake than the E-Type in the videos, and in some cases instability of airflow at points, they show a much lower Cd than the E-Type. They all have sloped rear areas leading to a chopped-off tail. The improved flow at the rear must more than offset the drag of the turbulent wake. Must also apply to the huge turbulent wake of the E-Type OTS in your visualization since it's not much slower than the coupe in real life.

[@qwkutiub]

Jerry Mouton Interesting point, I didn't think of the japanese cars' shape as of some kind of Kamm back. What do you think has the most influence on the Jag's drag, the windshield or the tail? GraysGarage Can you make a video explaining Kamm's principle? I'd really like to see a 60's chopped-off tail in the water channel.

[@MikeMilton]

This was a most interesting video, thanks. I own both an S1 OTS and an S2 FHC. Your approximation of the FHC is a bit off (the top is flatter to the driver's head position and then curves down more sharply). That likely does not make much difference. The lack of operating hood louvers on the model might make more of a difference (I'd be interested in your thoughts, along with your thoughts about the impact of air moving under the vehicle. I don't recall my hair being blown forward (when I had hair ;-) but I do know one could drive through quite significant rain and stay dry at even modest speed.

[@thomaskirkham3772]

Great video. Jaguar built an XKE known as the Low Drag Coupe and also as the Linder Knocker car. www.topspeed.com/cars/jaguar/1964-jaguar-lindner-nocker-low-drag-e-type-ar109244.html Another XKE that was raced were the lightweight (aluminum bodywork) with hard tops. The hard tops had vents in the top. www.netcarshow.com/jaguar/2014-lightweight_e-type/1024x768/wallpaper_0c.htm The vents in the trunk lid were used to help cool the inboard rear disk brakes.

[@RotaryRebuilder]

Thomas, thank you for the info. I'll take a look into these.

[@dewercompany]

Great job gray , i couldnt figure out how lower stagnation point at the front of vheicle can improve aero of a car and reduce drag and lift.

[@mantasisganaitis2281]

Interesting that the design of Malcolm Sayer has this high Cd. Though I suppose overall drag wouldn't be that bad, because of frontal area. By the way, I have done a 3D model of Jaguar XJ13. I also have modeled shapes of Lowdrag E-type (racing version of E-type), and also I have modeled the shape of a Dtype. I think they are not too far from true shapes. Thats in 3D, to get only the profile right is not very difficult, because thats basically 2D.

[@ltao328]

Hi Gray, I appreciate your efforts into explaining vehicle aerodynamics to us novices in this fascinating way. I believe your profile of the E Type coupe is wrong. If you look at your reference photos, the roof line is reasonable horizontal until the B pillar. The high quarter window then creates a delayed convex slope to the rear bumper. Your coupe has too much of a gentle slop to the rear bumper and it starts from the top of the windscreen. I can't wait until you get to Kamm tails. There is a fascinating story behind the Shelby's Daytona rear spoiler. Also, may I request a video of the Ferrari 250 GT Breadvan and Citroen DS 21 in the future?

[@RotaryRebuilder]

As I stated, I tried my best to profile the hardtop as best I could, it was difficult. I can definitely put Kamm tails on the list of "to-do", good suggestion. I don't have either the 250gt or DS 21 models, if you happen to have them or are willing to send them to me, I can get them tested.

[@ruigoncalves2]

I notice that in my NA MX-5 the forward wind buffeting stops when I pop up the aftermarket windblocker, will this also reduce drag overall or just place the vortex further back?

[@kninsiriphakdi572]

could it be possible with vw beetle.great work what you're doing.

[@ColocasiaCorm]

Watch at 2x for normal speed.

[@C4BO05E]

you should do rally cars vs stock like ken block

[@jerrymouton]

Interesting to see the complete turbulent separation behind the OTS (Open Two Seater) windshield compared with the relatively smooth flow at the rear of the FHC (Fixed Head Coupe to use Jag-speak). Yet, while the FHC was a little faster at the top end, it was not THAT much faster than the OTS: I'd expect a bigger differential. Maybe the effect behind the windshield is similar to what Dr. Kamm found about cut-off tails rather than long smooth ones -- less flow at the surface meant less drag? What do you think? Boy, what you really want to do with your setup is fiddle with things and see what the results would likely be. If you take the REAL HP of the E-Type engine (~ 200 at the rear wheels), the frontal area, and the CD of 0.44, would 150 MPH be realistic? Seems unlikely to me. It would be interesting to see the results of that calculation (please). How about parasitic drag? Some of us have felt that the effect of the large drip channels and the poorly faired-in glass (by today's standards) were also contributors. Thanks for a superb video! I have a 1964 S1 E-Type FHC and it was very educational to me. Jerry Mouton

[@RotaryRebuilder]

Jerry, I'll be running through the calculation of top speed shortly in a video. I'm curious also, since several "reviewers" who drove the car stated that they were able to get up to 150mph. Stay tuned!

[@jerrymouton]

GraysGarage I actually managed to work out the Cd required for the E-Type to hit 150 MPH; plenty of issues with the units that I had to get. Given the factory torque curves for the XK engine and E-Type gears and 17.5 ft² frontal area, you could hit 150 (theoretically) with a Cd of 0.73 or lower. So, a 0.44 Cd is not disproven by this means. It's well known in E-Type circles that reviewers (at least up to 1964's Road & Track test) were given cars that had been "breathed upon" by the factory to insure they could reach 150MPH! The '64 and later tests used higher numerical axle ratios that could not even theoretically reach 150 but were quicker (and what was provided in the US).

[@hugolara8838]

You mentioned that under low speed flow conditions, the flow does not actually make contact with the front of the bumper (at the stagnation point). Is this because of the boundary layer formed on the surface? Does this change with different flow conditions? I'm an aero student halfway through my first aero class and we have yet to cover these topics.

[@dee106ful]

Does the series 2 windshield being more upright cause even greater drag.

[@mmmboobs]

Don't know if you'd be interested, but i have a 1/64 Lamborghini Miura by Kyosho that I'd be willing to ship to you if you'd like to do a video on it. Let me know, i have no use for it and would love to see data on the Miura.

[@RotaryRebuilder]

1/64 is too small to properly simulate and visualize the dynamics unfortunately. I need something 1/24 or bigger, but thanks for the offer!

[@beyondthelol]

am i the only one that thinks it looks fucking awful haha

[@beyondthelol]

Nope, i like cars over all generations, but this car is just not a good looking car to my eye

[@beyondthelol]

***** I think that it is one of the most ''badass'' cars i have ever seen, using that adjective literally

[@beyondthelol]

***** Yeah, its fantastic looking. I really would love to own one if i had a ginormous garage and a massive bank balance haha. Ive never seen one here in nz though