Dumb spoiler question (probably)
11-30-2012, 11:41 AM
#16
Rennlist Member
When I was building time towards my Commercial and Instructor's licences, we had a C-152 at the club that nobody wanted to fly because 100LL wasn't available and as a result the plugs would foul (so they said). The C-150 had the Continental O-200 and the newer C-152, the Lycoming O-235. I had no issues with the C-152. I leaned it everywhere and put lots of time on it at the discounted rate of $19 per hour at the wet rate. It had a cruise prop and was fast. Those were the days!
I guess you had one of those flat-panel electronic CHT/EGT gauges. The C-172RG I rented had traditional analog gauges.
I guess you had one of those flat-panel electronic CHT/EGT gauges. The C-172RG I rented had traditional analog gauges.
11-30-2012, 11:46 AM
#17
Rennlist Member
Interesting comments regarding the rear spoiler and your "tests". Odd that Porsche would go through the engineering exercise and expense for this spoiler feature for little more than cosmetic reasons.
Unless you place thermocouples under the sparkplugs and measure the CHT's under identical driving conditions, with and without the spoiler deployed, your oil temp test is meaningless.
Unless you place thermocouples under the sparkplugs and measure the CHT's under identical driving conditions, with and without the spoiler deployed, your oil temp test is meaningless.
I didn't intend to represent what I did as a scientific experiment and was careful to indicate that the only measure I used was the oil temp gauge. My conclusions were drawn for my situation only and I made no recommendations that anyone else do what I've done...Is there a problem with that?
Oh, the source of the information on the effect(s) of the rear spolier was a book and a couple of articles written by Paul Frere...You may have heard of him.
Regards,
Terry
11-30-2012, 12:08 PM
#18
Rennlist Member
Mike,
I didn't intend to represent what I did as a scientific experiment and was careful to indicate that the only measure I used was the oil temp gauge. My conclusions were drawn for my situation only and I made no recommendations that anyone else do what I've done...Is there a problem with that?
Oh, the source of the information on the effect(s) of the rear spolier was a book and a couple of articles written by Paul Frere...You may have heard of him.
Regards,
Terry
I didn't intend to represent what I did as a scientific experiment and was careful to indicate that the only measure I used was the oil temp gauge. My conclusions were drawn for my situation only and I made no recommendations that anyone else do what I've done...Is there a problem with that?
Oh, the source of the information on the effect(s) of the rear spolier was a book and a couple of articles written by Paul Frere...You may have heard of him.
Regards,
Terry
11-30-2012, 12:32 PM
#19
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Interesting comments regarding the rear spoiler and your "tests". Odd that Porsche would go through the engineering exercise and expense for this spoiler feature for little more than cosmetic reasons.
Unless you place thermocouples under the sparkplugs and measure the CHT's under identical driving conditions, with and without the spoiler deployed, your oil temp test is meaningless.
Unless you place thermocouples under the sparkplugs and measure the CHT's under identical driving conditions, with and without the spoiler deployed, your oil temp test is meaningless.
It's a bit harsh to call this test meaningless. Would it mean something if it had risen significantly? There is an unanswered question about the spoilers usefullness at reducing heat, but given that Porsche's engineers didn't make the spoiler go up based on temps and/or speed would put me on the side of it not making any significant cooling difference until proven otherwise.
And why are you referring to engineering expenses for an aerodynamic device that everyone agrees is necessary at high speeds to a debate on heat transfer? The spoiler has to go up and down - form for looks and function for down force. And it can't go up and down at the same speed for obvious reasons. You make an assumption that the engineers were the only ones in the room when this was happening. I think marketing (and possibly legal) might have had as much or more input on when the spoiler rises and falls than the engineers, but that is just my opinion.
QuakerJacket
11-30-2012, 12:50 PM
#20
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Agreed +1 to cooling.
Back in the day Bruce Anderson of 911 fame remarked that the "raised spoiler" is there to maintain air flow quantites over the engine. Seems at speeds above 85kph (52+mph) the air passing over the engine grill needs assistance being directed into the engine area. Minor functionality for sure.
When driving once the spoiler is up, or down for that matter, one hit of the button keeps the spoiler in place until the ignition is cut. Around town the up and down action of the spoiler is a little much..... I'm just saying.
11-30-2012, 12:59 PM
#21
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12-01-2012, 08:43 AM
#22
button queen
Let's think about the effects of removing the engine under tray on the aero and cooling.
I posted on another thread my "conjecture" (fed by some aero courses at school....yes a little knowledge is a dangerous thing) that the tray and spoiler, operating as an integrated whole, would require the spoiler due to the aero and probably the cooling. With the undertray removed, as most of us have done, we permit undercar turbulence and air to enter the engine bay from below in ways not originally designed.
As well, the high speed aero and lift effects are dampened by more turbulance introduced below the car thereby reducing or eliminating the need for the spoiler up top. Think of an aircraft wing with speed brakes or spoilers deployed below the wing....that lift is destroyed or "spoiled".
Personally I've done the mod and had the car (spoiler down) in very "sporty" driving, in hot humid weather, as well as speeds up to 120, and have seen no evidnece of instabilities or cooling issues. But then there are no thermocouples up my butt either.
Just "conjecture"....maybe some of the aero majors from college can comment?
I posted on another thread my "conjecture" (fed by some aero courses at school....yes a little knowledge is a dangerous thing) that the tray and spoiler, operating as an integrated whole, would require the spoiler due to the aero and probably the cooling. With the undertray removed, as most of us have done, we permit undercar turbulence and air to enter the engine bay from below in ways not originally designed.
As well, the high speed aero and lift effects are dampened by more turbulance introduced below the car thereby reducing or eliminating the need for the spoiler up top. Think of an aircraft wing with speed brakes or spoilers deployed below the wing....that lift is destroyed or "spoiled".
Personally I've done the mod and had the car (spoiler down) in very "sporty" driving, in hot humid weather, as well as speeds up to 120, and have seen no evidnece of instabilities or cooling issues. But then there are no thermocouples up my butt either.
Just "conjecture"....maybe some of the aero majors from college can comment?
Last edited by DanL993; 12-01-2012 at 09:04 AM.
12-01-2012, 10:05 AM
#23
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Word around the campfire (conjecture of the minor kind!) is the underside chassis engine tray is for noise control via engine encapsulation. i.e., Switzerland regulations, where cow' s are pampered.
Not so much for underside chassis air flow contours.... True story, over heard with me own two ears at a Werk 1 campfire.
Not so much for underside chassis air flow contours.... True story, over heard with me own two ears at a Werk 1 campfire.
12-01-2012, 10:26 AM
#24
Three Wheelin'
I'm not positive...but I thnk the European 993s have a spoiler module that operate just like the Ruf module...ie...raises at 80 mph and lowers at 40 mph. If that is the case...the idea that the spoiler being unraised in the 10 - 39 mph range will cause excess heating is not correct...
I put the Ruf module in my car about a year after I bought the car...best mod I have done. That up/down all the time in traffic drove me nuts!
BTW...this is the first I've heard of the "make the spoiler operation manual" mod...I think I would like that...as the RUf module was like $70 11 years ago!
I put the Ruf module in my car about a year after I bought the car...best mod I have done. That up/down all the time in traffic drove me nuts!
BTW...this is the first I've heard of the "make the spoiler operation manual" mod...I think I would like that...as the RUf module was like $70 11 years ago!
12-01-2012, 10:37 AM
#25
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You don't need one. The "butt" of your Porsche already has one that you can connect to.
I'm glad the "aero majors from college" don't have the final word and that someone actually takes the plane up for countless tests before loading us people into them. I prefer the stop guessing and start taking measurements approach. The guessing approach other than putting you into the ballpark some of the time, is a waste of time.
I'm glad the "aero majors from college" don't have the final word and that someone actually takes the plane up for countless tests before loading us people into them. I prefer the stop guessing and start taking measurements approach. The guessing approach other than putting you into the ballpark some of the time, is a waste of time.
12-01-2012, 10:45 AM
#26
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You mean "above" the wing. That is why those things that pivot up on top of the wing are called spoilers. They use them in the air and during the landing roll. Then there are also spoilerons that have their own set of advantages.
12-01-2012, 12:52 PM
#28
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What is annoying is the unnecessary retraction when coming to a stop at an intersection or a traffic light.
What Porsche should have been done is design it with some "smarts".
12-01-2012, 01:01 PM
#29
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Operates the same way as my old Corrado's, which I think was the first production car to have a speed activated rear wing. However it actuated at freeway speeds ~55mph. tbh though I didn't think it help much with downforce but looked cool.
12-01-2012, 02:27 PM
#30
Race Director
why is annoying that it retracts at a stop? If its not noisy, then why does it matter?