I'm sure this has been discussed before. Since the pop-up rear spoiler blocks a great deal of the view rearward, is there a known way to keep it down until it's wanted, even at speeds over 70 mph.?

As best I can tell, the console switch has no effect in trying to put a deployed spoiler down.

It requires at least two things to activate it: a signal (speed) and power to the motor. Seems like either of those circuits could be interrupted by a driver-operated switch.

Thanx, guys.

 

Attached may help.

 

See this thread: https://www.jaguarforums.com/forum/f...-ftype-121672/
and particularly the last post: https://www.jaguarforums.com/forum/f...7/#post1614196
Works perfectly on the coupe, dunno about the vert.

 

Out of interest, has anyone noticed any handling differences since defeating the spoiler?


I'm talking about speeds higher than say, 70mph?

 

+1. Like around 196?

 

It must be producing what - 25 pounds of downforce on a 3500 pound car at 80 MPH - but I swear that the car feels better with the wing up. I often speed up to 72 to get the wing up and then slow down enough to avoid tickets....

 

... however it is FUGLY.

 

This is a spoiler, so it doesn't produce downforce; rather it reduces lift. Similar property of aerodynamics, but it's not as linear of an increase compared to a wing which provides downforce.

 

+1

 

I beg to differ; A flat plate (in essence what we have on the F-Type Coupe) angled up in the airflow will produce a downward force.


Air is being deflected upwards, so the resulting force will be downwards...correct?



Try holding a flat plate of equal size out of the window at 80 MPH at a similar angle; I thin you will be surprised by the amount of force it will put on your arms!

 

Nope... the spoiler pops up to defeat the low pressure zone created by the air moving over top of the car. That low pressure zone is pulling the car upwards and creating lift towards the rear of the vehicle. When the spoiler deploys, the low pressure zone is reduced and the lifting force disappears to some extent, however there isn't any additional force pushing downwards on the vehicle outside of gravity. This is exactly how an airplane wing works.


A wing on the other hand creates a low pressure zone on purpose which actually pulls the wing downwards towards the ground. And since the wing is attached to the car, the whole vehicle is forced downwards in relation to the wing. This downforce increases the weight of the vehicle pushing down on the track. This is why forumula 1 cars actually handle worse at slow speeds compared to high speeds; because they need the downforce.

 

Keep in mind the flat plate of the spoiler isn't out in the open air. So it reacts completely differently. Some air hits it, yes but it's more used to hold a pocket of high pressure than it is to create any sort of drag that might push downwards.

 

Apologies to abstruse1 for wandering off the topic, but I'm sure others find this interesting as well...



OK, I follow that, I wasn't respecting that the cars' section is actually an aerofoil shape in itself.


So, we are effectively deploying an air-brake as one would on a conventional aircraft, to 'spoil' the laminar'ish airflow over it and thus dumping lift (in turn lowering the low pressure area behind, and above/rear of the car)...correct now?!

 

It's probably more like 60 lbs at 80mph (264lbs @ 186mph).


Edit: 48.83802 lbs @ 80mph

 

Yup, that's basically the idea. Design is pretty important to minimize drag while its up, which is why the coupe and the convertible have completely different designs.

 

Well, I succeeded in selectively disabling the spoiler. After spending a lot of time at the fuse box in the driver's footwell, I realized that I couldn't much hope to find the correct wire, especially since access is so bad. So I interrupted the opening power wire at the spoiler motor with a rocker switch mounted in the trunk lid. Pretty easy to do once one's figured out how to remove the various panels.

 

Just don't go over 83.4MPH....

 

Oh, never. Especially in a school zone.

I was running at the Texas Mile a few years back (my best run was 195.5 mph in a Mustang, ~1,300 hp.) and a Nissan GT wadded up at the end. Talk was that they had removed the rear spoiler for a few more mph and the car traded ends. Not fun at near 200 mph.

So nothing over...well...